['CMV Parts and Maintenance']
['Vehicle maintenance']
01/08/2025
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[Editor’s Note: This section is added effective February 18, 2025.][Change Notice]
S1. Scope. This standard specifies requirements for protection from harmful electric shock, fire, explosion, and gas venting during normal vehicle operation and during and after a crash.
S2. Purpose. The purpose of this standard is to reduce deaths and injuries during normal vehicle operations and during and after a crash that occur because of electrolyte leakage, intrusion of electric energy storage/conversion devices into the occupant compartment, electric shock, fire, explosion, and gas venting, including deaths and injuries due to driver error.
S3. Application. (a) This standard applies to passenger cars, multipurpose passenger vehicles, trucks, and buses that use electrical propulsion components with working voltages greater than 60 volts direct current (VDC) or 30 volts alternating current (VAC), and whose speed attainable over a distance of 1.6 km on a paved level surface is more than 40 km/h.
(b) Mandatory applicability begins September 1, 2027, for vehicles with a gross vehicle weight rating of 4,536 kilograms (kg) or less and September 1, 2028, for vehicles with a gross vehicle weight rating over 4,536 kg. Small-volume manufacturers, final-stage manufacturers, and alterers are provided an additional year to comply with the requirements beyond the dates identified in this paragraph (b).
S4. Definitions.
Active driving possible mode
means the vehicle mode when application of pressure to the accelerator pedal (or activation of an equivalent control) or release of the brake system causes the electric power train to move the vehicle.
Automatic disconnect
means a device that when triggered, conductively separates a high voltage source from the electric power train or the rest of the electric power train.
Breakout harness
means connector wires that are connected for testing purposes to the REESS on the traction side of the automatic disconnect.
Capacitor
means a device used to store electrical energy, consisting of one or more pairs of conductors separated by an insulator: x-capacitors are connected between electrical mains or neutral and y-capacitors are connected between a main to ground.
Charge connector
is a conductive device that, by insertion into a vehicle charge inlet, establishes an electrical connection of the vehicle to an external electric power supply for the purpose of transferring energy.
Chassis dynamometer
means a mechanical device that uses one or more fixed roller assemblies to simulate different road conditions within a controlled environment and is used for a wide variety of vehicle testing.
Connector
means a device providing mechanical connection and disconnection of high voltage electrical conductors to a suitable mating component, including its housing.
n C Rate
means the constant current of the REESS, which takes 1/n hours to charge or discharge the REESS between 0 and 100 percent state of charge.
Direct contact
is the contact of any person or persons with high voltage live parts.
Electric energy storage device
means a high voltage source that stores energy for vehicle propulsion. This includes, but is not limited to, a high voltage battery or battery pack, rechargeable energy storage device, and capacitor module.
Electric energy storage/conversion device
means a high voltage source that stores or converts energy for vehicle propulsion. This includes, but is not limited to, a high voltage battery or battery pack, fuel cell stack, rechargeable energy storage device, and capacitor module.
Electric energy storage/conversion system
means an assembly of electrical components that stores or converts electrical energy for vehicle propulsion. This includes, but is not limited to, high voltage batteries or battery packs, fuel cell stacks, rechargeable energy storage systems, capacitor modules, inverters, interconnects, and venting systems.
Electric power train
means an assembly of electrically connected components which includes, but is not limited to, electric energy storage/conversion systems and propulsion systems.
Electrical chassis
means conductive parts of the vehicle whose electrical potential is taken as reference and which are:
(1) Conductively linked together, and
(2) Not high voltage sources during normal vehicle operation.
Electrical isolation
of a high voltage source in the vehicle means the electrical resistance between the high voltage source and any of the vehicle's electrical chassis divided by the working voltage of the high voltage source.
Electrical protection barrier
is the part providing protection against direct contact with high voltage live parts from any direction of access.
Electrolyte leakage
means the escape of liquid electrolyte from the REESS.
Exposed conductive part
is a conductive part that can be touched under the provisions of the IPXXB protection degree and that is not normally energized, but that can become electrically energized under isolation fault conditions. This includes parts under a cover if the cover can be removed without using tools.
External charging mode
means the vehicle mode when the REESS is charging with external electric power supply connected through the charge connector to the vehicle charge inlet.
External electric power supply
is a power supply external to the vehicle that provides electric power to charge the electric energy storage device in the vehicle through the charge connector.
Fuel cell system
is a system containing the fuel cell stack(s), air processing system, fuel flow control system, exhaust system, thermal management system, and water management system.
High voltage live part
means a live part of a high voltage source.
High voltage source
means any electric component which is contained in the electric power train or conductively connected to the electric power train and has a working voltage greater than 30 VAC or 60 VDC.
Indirect contact
is the contact of any person or persons with exposed conductive parts.
Live part
is a conductive part of the vehicle that is electrically energized under normal vehicle operation.
Luggage compartment
is the space in the vehicle for luggage accommodation, separated from the passenger compartment by the front or rear bulkhead and bounded by a roof, hood or trunk lid, floor, and side walls, as well as by electrical protection barriers provided for protecting the occupants from direct contact with high voltage live parts.
Normal vehicle operation
includes operating modes and conditions that can reasonably be encountered during typical operation of the vehicle, such as driving, parking, and standing in traffic, as well as charging using chargers that are compatible with the specific charging ports installed on the vehicle. It does not include conditions where the vehicle is damaged, either by a crash or road debris, subjected to fire or water submersion, or in a state where service and/or maintenance is needed or being performed.
Parking mode
is the vehicle mode in which the vehicle power is turned off, the vehicle propulsion system and ancillary equipment such as the radio are not operational, and the vehicle is stationary.
Passenger compartment
is the space for occupant accommodation that is bounded by the roof, floor, side walls, doors, outside glazing, front bulkhead and rear bulkhead or rear gate, as well as electrical protection barriers provided for protecting the occupants from direct contact with high voltage live parts.
Propulsion system
means an assembly of electric or electro-mechanical components or circuits that propel the vehicle using the energy that is supplied by a high voltage source. This includes, but is not limited to, electric motors, inverters/converters, and electronic controllers.
Protection degree IPXXB
is protection from contact with high voltage live parts. It is tested by probing electrical protection barriers with the jointed test finger probe, IPXXB, in figure 7b to this standard.
Protection degree IPXXD
is protection from contact with high voltage live parts. It is tested by probing electrical protection barriers with the test wire probe, IPXXD, in figure 7a to this standard.
Rechargeable Electrical Energy Storage System (REESS)
means the rechargeable electric energy storage system that provides electric energy for electrical propulsion.
Rupture
means an opening through the casing of the REESS that would permit the IPXXB test probe to penetrate and contact live parts.
Service disconnect
is the device for deactivation of an electrical circuit when conducting checks and services of the vehicle electrical propulsion system.
State of charge (SOC)
means the available electrical charge in a REESS expressed as a percentage of the normal operating capacity specified by the vehicle manufacturer.
Thermal event
means the condition when the temperature within the REESS is significantly higher than the maximum operating temperature.
Thermal runaway
means an uncontrolled increase of cell temperature caused by exothermic reactions inside the cell.
Thermal propagation
means the sequential occurrence of thermal runaway within a REESS triggered by thermal runaway of a cell in the REESS.
VAC
means volts of alternating current (AC) expressed using the root mean square value.
VDC
means volts of direct current (DC).
Vehicle charge inlet
is the device on the electric vehicle into which the charge connector is inserted for the purpose of transferring energy and exchanging information from an external electric power supply.
Venting
means the release of excessive internal pressure from cell or battery in a manner intended by design to preclude rupture or explosion.
Working voltage
means the highest root mean square voltage of the voltage source, which may occur across its terminals or between its terminals and any conductive parts in open circuit conditions or under normal operating conditions.
S5. General requirements.
S5.1 Vehicles of GVWR of 4,536 kilograms (kg) or less (light vehicles). Each vehicle with a GVWR of 4,536 kg or less shall meet the requirements set forth in S6 (normal vehicle operation safety), S8 (post-crash safety), S11 (vehicle controls managing REESS safe operations), S13 (warning in the case of thermal event in REESS), and S14 (water exposure safety) of this standard.
S5.2 Vehicles with a GVWR greater than 4,536 kg other than school buses (heavy vehicles other than school buses). Each heavy vehicle with a GVWR greater than 4,536 kg, other than school buses, shall meet the requirements set forth in S6 (normal vehicle operation safety), S11 (vehicle controls managing REESS safe operations), S13 (warning in the case of thermal event in REESS), and S14 (water exposure safety) of this standard.
S5.3 School buses with a GVWR greater than 4,536 kg. Each school bus with a GVWR greater than 4,536 kg shall meet the requirements set forth in S6 (normal vehicle operation safety), S8 (post-crash safety), S11 (vehicle controls managing REESS safe operations), S13 (warning in the case of thermal event in REESS), and S14 (water exposure safety) of this standard.
S6. Normal vehicle operation safety. Each vehicle to which this standard applies must meet the requirements in S6.1 to S6.6 of this standard, when tested according to the relevant provisions in S7 of this standard.
S6.1 Protection against direct contact.
S6.1.1 Marking. The symbol shown in figure 6 to this standard shall be present on or near electric energy storage devices. The symbol in figure 6 shall also be visible on electrical protection barriers which, when removed, expose live parts of high voltage sources. The symbol shall be yellow and the bordering and the arrow shall be black.
S6.1.1.1 The marking is not required for electrical protection barriers that cannot be physically accessed, opened, or removed without the use of tools. Markings are not required for electrical connectors or the vehicle charge inlet.
S6.1.2 High voltage cables. Cables for high voltage sources which are not located within electrical protection barriers shall be identified by having an outer covering with the color orange.
S6.1.3 Service disconnect. For a service disconnect which can be opened, disassembled, or removed without tools, protection degree IPXXB shall be provided when tested under procedures specified in S7.3.1 of this standard using the IPXXB test probe shown in figures 7a and 7b to this standard.
S6.1.4 Protection degree of high voltage live parts. (a) Protection degree IPXXD shall be provided for high voltage live parts inside the passenger or luggage compartment when tested according to the procedures specified in S7.3.1 of this standard using the IPXXD test probe shown in figure 7a to this standard.
(b) Protection degree IPXXB shall be provided for high voltage live parts in areas other than the passenger or luggage compartment when tested according to the procedures specified in S7.3.1 of this standard using the IPXXB test probe shown in figures 7a and 7b to this standard. High voltage live parts that are not energized except during charging of the REESS are excluded from protection degree IPXXB if they are located on the vehicle roof such that the wrap around distance from the instep of the vehicle, or the lowest step (if multiple steps are present) of the vehicle, to the high voltage source is at least 3 meters.
S6.1.5 Connectors. All connectors shall provide direct contact protection by:
(a) Meeting the requirements specified in S6.1.4 when the connector is connected to its corresponding mating component; and,
(b) If a connector can be separated from its mating component without the use of a tool, meeting at least one of the following conditions from S6.1.5(b)(1), (2), or (3):
(1) The connector meets the requirements of S6.1.4 when separated from its mating component;
(2) The voltage of the live parts becomes less than or equal to 60 VDC or 30 VAC within one second after the connector is separated from its mating component; or
(3) The connector requires at least two distinct actions to separate from its mating component and there are other components that must be removed in order to separate the connector from its mating component and these other components cannot be removed without the use of tools.
S6.1.6 Vehicle charge inlet. Direct contact protection for a vehicle charge inlet shall be provided by meeting the requirements specified in S6.1.4 when the charge connector is connected to the vehicle inlet and by meeting at least one of the requirements of S6.1.6(a) or (b).
(a) The vehicle charge inlet meets the requirements of S6.1.4 when the charge connector is not connected to it; or
(b) The voltage of the high voltage live parts becomes equal to or less than 60 VDC or equal to or less than 30 VAC within 1 second after the charge connector is separated from the vehicle charge inlet.
S6.2 Protection against indirect contact.
S6.2.1 The resistance between all exposed conductive parts of electrical protection barriers and the electrical chassis shall be less than 0.1 ohms when tested according to the procedures specified in S7.3.2 of this standard.
S6.2.2 The resistance between any two simultaneously reachable exposed conductive parts of the electrical protection barriers that are less than 2.5 meters from each other shall be less than 0.2 ohms when tested according to the procedures specified in S7.3.2 of this standard.
S6.3 Electrical isolation.
S6.3.1 Electrical isolation of AC and DC high voltage sources. The electrical isolation of a high voltage source, determined in accordance with the procedure specified in S7.2 of this standard, must be greater than or equal to one of the following:
(a) 500 ohms/volt for an AC high voltage source;
(b) 100 ohms/volt for an AC high voltage source if it is conductively connected to a DC high voltage source, but only if the AC high voltage source meets the requirements for protection against direct contact in S6.1.4 and the protection from indirect contact in S6.2; or
(c) 100 ohms/volt for a DC high voltage source.
S6.3.2 Exclusion of high voltage sources from electrical isolation requirements. A high voltage source that is conductively connected to an electric component which is conductively connected to the electrical chassis and has a working voltage less than or equal to 60 VDC, including a pulsating DC voltage source without a change in polarity, is not required to meet the electrical isolation requirements in S6.3.1 if the voltage between the high voltage source and the electrical chassis is less than or equal to 30 VAC or 60 VDC.
S6.3.3 Electrical isolation of high voltage sources for charging the electric energy storage device. For the vehicle charge inlet intended to be conductively connected to the AC external electric power supply, the electric isolation between the electrical chassis and the high voltage sources that are conductively connected to the vehicle charge inlet during charging of the electric energy storage device shall be greater than or equal to 500 ohms/volt when the charge connector is disconnected. The electrical isolation is measured at the high voltage live parts of the vehicle charge inlet and determined in accordance with the procedure specified in S7.2 of this standard. During the measurement, the electric energy storage device may be disconnected.
S6.4 Electrical isolation monitoring. DC high voltage sources of vehicles with a fuel cell system shall be monitored by an electrical isolation monitoring system that displays a warning for loss of isolation when tested according to S7.4 of this standard. The system must monitor its own readiness and the visual warning display must be provided to the driver. For a vehicle with automated driving systems and without manually operated driving controls, the visual warning must be provided to all the front row occupants.
S6.5 Electric shock protection during charging. For motor vehicles with an electric energy storage device that can be charged through a conductive connection with a grounded external electric power supply, a device to enable conductive connection of the electrical chassis to the earth ground shall be provided. This device shall enable connection to the earth ground before exterior voltage is applied to the vehicle and retain the connection until after the exterior voltage is removed from the vehicle.
S6.6 Mitigating driver error.
S6.6.1 Indicator of active driving possible mode. At least a momentary indication shall be given to the driver each time the vehicle is first placed in active driving possible mode after manual activation of the propulsion system. This requirement does not apply under conditions where an internal combustion engine directly or indirectly provides the vehicle's propulsion power when the vehicle is first placed in the active driving possible mode after manual activation of the propulsion system.
S6.6.2 Indicator of active driving possible mode when leaving the vehicle. When leaving the vehicle, the driver shall be informed by an auditory or visual signal if the vehicle is still in the active driving possible mode.
S6.6.3 Prevent drive-away. If the on-board electric energy storage device can be externally charged, vehicle movement of more than 150 mm by its own propulsion system shall not be possible as long as the charge connector of the external electric power supply is physically connected to the vehicle charge inlet in a manner that would permit charging of the electric energy storage device.
S7. Electrical safety test procedures for normal vehicle operation safety. The following provisions specify the test procedures associated with the requirements of S6 of this standard.
S7.1 Voltage measurements. For the purpose of determining the voltage level of the high voltage source, voltage is measured as shown in figure 1 to this standard using a voltmeter that has an internal resistance of at least 10 MΩ. All post-crash voltage measurements for determining electrical isolation of high voltage sources specified in S8.2(a) of this standard are made at least 10 seconds after impact. All post-crash voltage measurements for determining the voltage levels specified in S8.2(b) of this standard and the energy in capacitors specified in S8.2(d) of this standard are made between 10 to 60 seconds after impact.
S7.1.1 For a high voltage source that has an automatic disconnect that is physically contained within itself, the voltage measurement after the test is made from the side of the automatic disconnect connected to the electric power train or to the rest of the electric power train if the high voltage source is a component contained in the power train. For a high voltage source that has an automatic disconnect that is not physically contained within itself, the voltage measurement after the test is made from both the high voltage source side of the automatic disconnect and from the side of the automatic disconnect connected to the electric power train or to the rest of the electric power train if the high voltage source is a component contained in the power train.
S7.1.2 Voltage Vb is measured across the two terminals of the voltage source. Before a vehicle crash test, Vb is equal to or greater than the working voltage as specified by the vehicle manufacturer.
S7.1.3 Voltage V1 is measured between the negative side of the high voltage source and the electrical chassis as shown in figure 2 to this standard. Voltage V2 is measured between the positive side of the high voltage source and the electrical chassis as shown in figure 3 to this standard.
S7.2 Test method for determining electrical isolation. Measure the voltages V1, V2, and Vb as shown in figure 1 to this standard in accordance with S7.1.
S7.2.1 If V1 is greater than or equal to V2, insert a known resistance (Ro) between the negative side of the high voltage source and the electrical chassis. With the Ro installed, measure the voltage (V1') as shown in figure 4 to this standard between the negative side of the high voltage source and the electrical chassis. Calculate the electrical isolation resistance (Ri) according to the formula shown. Divide Ri (in ohms) by the working voltage of the high voltage source (in volts) to obtain the electrical isolation (in ohms/volt).
S7.2.2 If V2 is greater than V1, insert a known resistance (Ro) between the positive side of the high voltage source and the electrical chassis. With the Ro installed, measure the voltage (V2') as shown in figure 5 to this standard between the positive side of the high voltage source and the electrical chassis. Calculate the electrical isolation resistance (Ri) according to the formula shown. Divide Ri (in ohms) by the working voltage of the high voltage source (in volts) to obtain the electrical isolation (in ohms/volt).
S7.3 Test methods for evaluating physical barrier protection.
S7.3.1 Test method to evaluate protection from direct contact with high voltage sources. (a) Any parts surrounding the high voltage components are opened, disassembled, or removed without the use of tools.
(b) The selected access probe is inserted into any gaps or openings of the electrical protection barrier with a test force between 9 Newton to 11 Newton with the IPXXB probe or 1 Newton to 2 Newton with the IPXXD probe. If the probe partly or fully penetrates into the electrical protection barrier, it is placed in every possible position to evaluate contact with high voltage live parts. If partial or full penetration into the electrical protection barrier occurs with the IPXXB probe, the IPXXB probe shall be placed as follows: starting from the straight position, both joints of the test finger are rotated progressively through an angle of up to 90 degrees with respect to the axis of the adjoining section of the test finger and are placed in every possible position.
(c) A low voltage supply (of not less than 40 V and not more than 50 V) in series with a suitable lamp may be connected between the access probe and any high voltage live parts inside the electrical protection barrier to indicate whether high voltage live parts were contacted.
(d) A mirror or fiberscope may be used to inspect whether the access probe touches high voltage live parts inside the electrical protection barrier.
(e) Protection degree IPXXD or IPXXB is verified when the following conditions are met:
(1) The access probe does not touch high voltage live parts. The IPXXB access probe may be manipulated as specified in S7.3.1(b) for evaluating contact with high voltage live parts. The methods specified in S7.3.1(c) or S7.3.1(d) may be used to aid the evaluation. If method S7.3.1(c) is used for verifying protection degree IPXXB or IPXXD, the lamp shall not light up.
(2) The stop face of the access probe does not fully penetrate into the electrical protection barrier.
S7.3.2 Test method to evaluate protection against indirect contact with high voltage sources. Any parts surrounding the high voltage components are opened, disassembled, or removed without the use of tools. At the option of the manufacturer, protection against indirect contact with high voltage sources shall be determined using the test method in S7.3.2(a) or (b).
(a) Test method using a resistance tester. The resistance tester is connected to the measuring points (the electrical chassis and any exposed conductive part of electrical protection barriers or any two simultaneously reachable exposed conductive parts of electrical protection barriers that are less than 2.5 meters from each other), and the resistance is measured using a resistance tester that can supply current levels of at least 0.2 Amperes with a resolution of 0.01 ohms or less. The resistance between two exposed conductive parts of electrical protection barriers that are less than 2.5 meters from each other may be calculated using the separately measured resistances of the relevant parts of the electric path.
(b) Test method using a DC power supply, voltmeter, and ammeter. (1) Connect the DC power supply, voltmeter, and ammeter to the measuring points (the electrical chassis and any exposed conductive part or any two simultaneously reachable exposed conductive parts that are less than 2.5 meters from each other) as shown in figure 8 to this standard.
(2) Adjust the voltage of the DC power supply so that the current flow becomes more than 0.2 Amperes.
(3) Measure the current I and the voltage V shown in figure 8 to this standard.
(4) Calculate the resistance R according to the formula, R = V/I.
(5) The resistance between two simultaneously reachable exposed conductive parts of electrical protection barriers that are less than 2.5 meters from each other may be calculated using the separately measured resistances of the relevant parts of the electric path.
S7.3.3 Test method to determine voltage between exposed conductive parts of electrical protection barriers and the electrical chassis and between exposed conductive parts of electrical protection barriers. (a) Any parts surrounding the high voltage components are opened, disassembled, or removed without the use of tools.
(b) Connect the voltmeter to the measuring points (exposed conductive part of an electrical protection barrier and the electrical chassis or any two simultaneously reachable exposed conductive parts of electrical protection barriers that are less than 2.5 meters from each other).
(c) Measure the voltage.
(d) The voltage between two simultaneously reachable exposed conductive parts of electrical protection barriers that are less than 2.5 meters from each other may be calculated using the separately measured voltages between the relevant electrical protection barriers and the electrical chassis.
S7.4 Test method for evaluating on-board electrical isolation monitoring system. Prior to any impact test, the requirements of S6.4 of this standard for the on-board electrical isolation monitoring system shall be tested using the following procedure.
(a) The electric energy storage device is at the state of charge specified in S7.1.
(b) The switch or device that provides power from the electric energy storage/conversion system to the propulsion system is in the activated position or the ready-to-drive position.
(c) Determine the isolation resistance, Ri, of the high voltage source with the electrical isolation monitoring system using the procedure outlined in S7.2.
(d) Insert a resistor with resistance Ro equal to or greater than 1/(1/(95 times the working voltage of the high voltage source)−1/Ri) and less than 1/(1/(100 times the working voltage of the high voltage source)−1/Ri) between the positive terminal of the high voltage source and the electrical chassis.
(e) The electrical isolation monitoring system indicator shall provide a visual warning to the driver. For a vehicle with automated driving systems and without manually operated driving controls, the visual warning must be provided to all the front row occupants.
S7.5 Test method for determining post-crash energy in capacitors. (a) Prior to the crash tests, the vehicle manufacturer must identify the capacitors, type of capacitors (x-capacitors and y-capacitors) and their respective capacitance (Cx and Cy 1 and Cy 2 ) in the electric power train for which the low energy compliance option for post-crash electrical safety in S8.2(d) of this standard is applied.
(b) Voltages Vb, V1, and V2 are measured across the capacitors in accordance with S7.1.
(c) The total energy in a x-capacitor is equal to 0.5 × Cx × Vb 2 .
(d) The total energy in the y-capacitor Cy 1 is equal to 0.5 × Cy 1 × V1 2 and the total energy in the y-capacitor Cy 2 is equal to 0.5 × Cy 2 × V2 2 .
S8. Post-crash safety. Each vehicle with a GVWR of 4,536 kg or less to which this standard applies must meet the requirements in S8.1, S8.2, S8.3, and S8.4 when tested according to S9 of this standard under the conditions of S10 of this standard. Each school bus with a GVWR greater than 4,536 kg to which this standard applies must meet the requirements in S8.1, S8.2, S8.3, and S8.4 when tested according to S9.5 of this standard under the conditions of S10.
S8.1 Fire safety. Starting from the time of impact and continuing until one hour after the completion of the sequence of tests specified in S9 of this standard, there shall be no evidence of fire or explosion in any part of the vehicle. The assessment of fire or explosion is verified by visual inspection without disassembly of the REESS or vehicle.
S8.2 Electrical safety. After each test specified in S9 of this standard, each high voltage source in a vehicle must meet one of the following electrical safety requirements: electrical isolation requirements of S8.2(a), the voltage level requirements of S8.2 (b), or the physical barrier protection requirements of S8.2(c); or the high voltage capacitors in the electric power train must meet the low-energy requirements of S8.2(d).
(a) The electrical isolation of the high voltage source, determined in accordance with the procedure specified in S7.2 of this standard, must be greater than or equal to one of the following:
(1) 500 ohms/volt for an AC high voltage source;
(2) 100 ohms/volt for an AC high voltage source if it is conductively connected to a DC high voltage source, but only if the AC high voltage source meets the physical barrier protection requirements specified in S8.2(c)(1) and (2); or
(3) 100 ohms/volt for a DC high voltage source.
(b) The voltages V1, V2, and Vb of the high voltage source, measured according to the procedure specified in S7.1 of this standard, must be less than or equal to 30 VAC for AC components or 60 VDC for DC components.
(c) Protection against electric shock by direct and indirect contact (physical barrier protection) shall be demonstrated by meeting the following three conditions:
(1) The high voltage source (AC or DC) meets the protection degree IPXXB when tested according to the procedure specified in S7.3.1 of this standard using the IPXXB test probe shown in figures 7a and 7b to this standard;
(2) The resistance between exposed conductive parts of the electrical protection barrier of the high voltage source and the electrical chassis is less than 0.1 ohms when tested according to the procedures specified in S7.3.2 of this standard. In addition, the resistance between an exposed conductive part of the electrical protection barrier of the high voltage source and any other simultaneously reachable exposed conductive parts of electrical protection barriers within 2.5 meters of it must be less than 0.2 ohms when tested using the test procedures specified in S7.3.2 of this standard; and
(3) The voltage between exposed conductive parts of the electrical protection barrier of the high voltage source and the electrical chassis is less than or equal to 30 VAC or 60 VDC as measured in accordance with S7.3.3 of this standard. In addition, the voltage between an exposed conductive part of the electrical protection barrier of the high voltage source and any other simultaneously reachable exposed conductive parts of electrical protection barriers within 2.5 meters of it must be less than or equal to 30 VAC or 60 VDC as measured in accordance with S7.3.3 of this standard.
(d) The total energy of unidirectional single impulse currents from capacitors shall be less than 0.2 Joules when determined in accordance with the procedure specified in S7.5 of this standard.
S8.3 Electric energy storage/conversion device retention. During and after each test specified in S9 of this standard:
(a) Electric energy storage/conversion devices shall remain attached to the vehicle by at least one component anchorage, bracket, or any structure that transfers loads from the device to the vehicle structure, and
(b) Electric energy storage/conversion devices located outside the occupant compartment shall not enter the occupant compartment.
S8.4 Electrolyte leakage from electric energy storage devices. Not more than 5.0 liters of electrolyte shall leak from electric energy storage devices, and no visible trace of electrolyte shall leak into the passenger compartment. Leakage is measured from the time of the impact until 30 minutes thereafter, and throughout any static rollover after a barrier impact test, specified in S9 of this standard.
S9. Crash test specifications. A test vehicle with a GVWR less than or equal to 4,536 kg, under the conditions of S10 of this standard, is subject to any one single barrier crash test of S9.1, S9.2, or S9.3, followed by the static rollover test of S9.4. A school bus with a GVWR greater than 4,536 kg, under the conditions of S10, is subject to the contoured barrier crash test of S9.5. A particular vehicle need not meet further test requirements after having been subjected to a single barrier crash/static rollover test sequence.
S9.1 Frontal barrier crash. The test vehicle, with test dummies in accordance with S6.1 of §571.301, traveling longitudinally forward at any speed up to and including 48 km/h, impacts a fixed collision barrier that is perpendicular to the line of travel of the vehicle, or at an angle up to 30 degrees in either direction from the perpendicular to the line of travel of the vehicle.
S9.2 Rear moving barrier impact. The test vehicle, with test dummies in accordance with S6.1 of §571.301, is impacted from the rear by a barrier that conforms to S7.3(b) of §571.301 and that is moving at any speed between 79 and 81 km/h.
S9.3 Side moving deformable barrier impact. The test vehicle, with the appropriate 49 CFR part 572 test dummies specified in §571.214 at positions required for testing by S7.1.1, S7.2.1, or S7.2.2 of Standard 214 (§571.214), is impacted laterally on either side by a moving deformable barrier moving at any speed between 52.0 km/h and 54.0 km/h.
S9.4 Post-impact test static rollover. After each crash test specified in S9.1, S9.2, and S9.3, without any alteration of the vehicle, the vehicle is rotated on its longitudinal axis to each successive increment of 90 degrees under the test conditions of S10.3 of this standard.
S9.5 Moving contoured barrier crash. The test vehicle, under the conditions of S10.1 and S10.2 of this standard, is impacted at any point and at any angle by the moving contoured barrier assembly, specified in S7.5 and S7.6 in §571.301, traveling longitudinally forward at any speed up to and including 48 km/h.
S10. Crash test conditions.
S10.1 State of charge. The electric energy storage device(s) shall be at the state of charge specified in either S10.1(a), (b), or (c):
(a) At the maximum state of charge in accordance with the vehicle manufacturer's recommended charging procedures, as stated in the vehicle owner's manual or on a label that is permanently affixed to the vehicle; or
(b) If the manufacturer has made no recommendation for charging procedures in the owner's manual or on a label permanently affixed to the vehicle, at a state of charge of not less than 95 percent of the maximum capacity of the electric energy storage device(s); or
(c) If the electric energy storage device(s) is/are rechargeable only by an energy source on the vehicle, at any state of charge within the normal operating voltage defined by the vehicle manufacturer.
S10.2 Vehicle conditions. The switch or device that provides power from the electric energy storage/conversion system to the propulsion system is in the activated position or the ready-to-drive position. Bypass any devices or systems that do not allow the propulsion system to be energized at the time of impact when the vehicle ignition is on and the vehicle is in neutral.
S10.2.1 The parking brake is disengaged and the vehicle drive system is in the neutral position. In a test conducted under S9.3 of this standard, the parking brake is set.
S10.2.2 Tires are inflated to the manufacturer's specifications.
S10.2.3 The vehicle, including test devices and instrumentation, is loaded as follows:
(a) A passenger car is loaded to its unloaded vehicle weight plus its rated cargo and luggage capacity weight, secured in the luggage compartment, plus the necessary test dummies as specified in S9 of this standard, restrained only by means that are installed in the vehicle for protection at its seating position.
(b) A multipurpose passenger vehicle, truck, or bus, with a GVWR of 4,536 kg (10,000 lb) or less, is loaded to its unloaded vehicle weight plus the necessary dummies, as specified in S9 of this standard, plus 136 kg or its rated GVWR, whichever is less, secured in the load carrying area and distributed as nearly as possible in proportion to its GVWR. For the purpose of this standard, unloaded vehicle weight does not include the weight of work-performing accessories. Each dummy is restrained only by means that are installed in the vehicle for protection at its seating position.
(c) A school bus with a GVWR greater than 4,536 kg is loaded to its unloaded vehicle weight, plus 54 kg of unsecured mass at each designated seating position.
S10.3 Static rollover test conditions. The vehicle is rotated about its longitudinal axis, with the axis kept horizontal, to each successive increment of 90°, 180°, and 270° at a uniform rate, with 90° of rotation taking place in any time interval from 1 to 3 minutes. After reaching each 90° increment the vehicle is held in that position for 5 minutes.
S10.4 Rear moving barrier impact test conditions. The conditions of S7.3(b) and S7.6 of §571.301 apply to the conducting of the rear moving deformable barrier impact test specified in S9.2 of this standard.
S10.5 Side moving deformable barrier impact test conditions. The conditions of S8.9, S8.10, and S8.11 of §571.214 apply to the conduct of the side moving deformable barrier impact test specified in S9.3 of this standard.
S11. Vehicle controls managing REESS safe operations. Each vehicle to which the standard applies shall meet the requirements in S11.1, when tested according to S12 of this standard and the requirements in S11.2.
S11.1 When tested in accordance with the overcharge test in S12.1, the over-discharge test in S12.2, the overcurrent test in S12.3, the high-temperature test in S12.4, and the short circuit test in accordance with S12.5 of this standard, each vehicle shall meet the following:
(a) During the test, there shall be no evidence of electrolyte leakage, rupture, venting, fire, or explosion of the REESS as verified by visual inspection without disassembly of the vehicle.
(b) The isolation resistance of the high voltage sources measured after the test shall not be less than 100 ohms/volt when determined in accordance with S7.2 of this standard.
S11.2 In the event of operational failure of the vehicle controls that manage safe operation of the REESS, the vehicle must provide a visual warning while in active driving possible mode. The warning system shall monitor its own readiness and the visual warning must be provided to the driver. For a vehicle with automated driving systems and without manually operated driving controls, the visual warning must be provided to all the front row occupants.
S12. Test methods for evaluating vehicle controls managing REESS safe operations.
S12.1 Overcharge test. The overcharge test is conducted at ambient temperatures between 10 °C and 30 °C, with the vehicle REESS initially set between 90 to 95 percent SOC. The following steps are conducted to evaluate the vehicle's overcharge protection controls:
(a) A breakout harness is connected to the traction side of the REESS. The manufacturer must specify an appropriate location(s) and attachment point(s) to connect the breakout harness.
(b) Temperature probes are connected to the REESS outer casing to monitor changes in REESS temperature. Temperature measurements may also be obtained through communication with the REESS control module.
(c) The external charge/discharge equipment, with maximum voltage and current set at least 10 percent higher than the REESS voltage and current limits, is connected to the breakout harness.
(d) The vehicle switch or device that provides power to the vehicle controls that manage REESS operations is set to the activated position.
(e) The REESS is charged with the external charge/discharge equipment with the maximum charge current specified by the manufacturer. If the manufacturer does not specify an appropriate charge current, then a charge rate of 1/3 C is used.
(f) Charging is continued until one of the following occurs:
(1) The overcharge protection control terminates the charge current;
(2) The REESS temperature is 10 °C above the manufacturer-specified maximum operating temperature of the REESS; or
(3) 12 hours have passed since the start of charging the vehicle.
(g) After the charge current is terminated, if charge and discharge are permitted by the vehicle controls, a standard cycle is performed in accordance with S12.6.
(h) After the completion of the standard cycle, or if the standard cycle was not performed, after charging is terminated, the vehicle is observed for 1 hour for evidence of electrolyte leakage, rupture, venting, fire, or explosion of the REESS.
(i) At the conclusion of the test, electrical isolation of the REESS is determined in accordance with S7.2 of this standard.
S12.2 Over-discharge test. The over-discharge test is conducted at ambient temperatures between 10 °C and 30 °C, with the vehicle REESS initially set between 10 and 15 percent SOC. For a vehicle with on-board energy conversion systems such as an internal combustion engine or a fuel cell, the fuel supply is set to the minimum level where active driving possible mode is permitted. The following steps are conducted to evaluate the vehicle's over-discharge protection controls:
(a) A breakout harness is connected to the traction side of the REESS. The manufacturer must specify an appropriate location(s) and attachment point(s) to connect the breakout harness.
(b) Temperature probes are connected to the REESS outer casing to monitor changes in REESS temperature. Temperature measurements may also be obtained through communication with the REESS control module.
(c) The external charge/discharge equipment, with maximum voltage and current set at least 10 percent higher than the REESS voltage and current limits, is connected to the breakout harness.
(d) The vehicle switch or device that provides power from the REESS to the electric power train is set to the activated position or the active driving possible mode.
(e) The REESS is discharged with the external charge/discharge equipment with the maximum discharge rate under normal operating conditions specified by the manufacturer. If the manufacturer does not specify an appropriate discharge rate, a power load of 1kW is used.
(f) Discharging is continued until one of the following occurs:
(1) The over-discharge protection control terminates the discharge current;
(2) The temperature gradient of the REESS is less than 4°C through 2 hours from the start of discharge; or
(3) The vehicle is discharged to 25 percent of its working voltage level.
(g) After the discharge current is terminated, a standard cycle is performed in accordance with S12.6, if charge and discharge are permitted by the vehicle controls.
(h) After the completion of the standard cycle, or if the standard cycle was not performed, after discharging is terminated, the vehicle is observed for 1 hour for evidence of electrolyte leakage, rupture, venting, fire, or explosion of the REESS.
(i) At the conclusion of the test, electrical isolation of the REESS is determined in accordance with S7.2 of this standard.
S12.3 Overcurrent test. The overcurrent test is only conducted on vehicles that have the capability of charging by DC external electricity supply. The test is conducted at ambient temperatures between 10 °C and 30 °C, with the vehicle REESS initially set between 40 to 50 percent SOC. The following steps are conducted to evaluate the vehicle's over-current protection controls:
(a) A breakout harness is connected to the traction side of the REESS. The manufacturer must specify an appropriate location(s) and attachment point(s) to connect the breakout harness.
(b) Temperature probes are connected to the REESS outer casing to monitor changes in REESS temperature. Temperature measurements may also be obtained through communication with the REESS control module.
(c) The external charge/discharge equipment, with maximum voltage and current set at least 10 percent higher than the REESS voltage and current limits, is connected to the breakout harness.
(d) The vehicle switch or device that provides power to the vehicle controls that manage REESS operations is set to the activated position.
(e) The REESS is charged with the external charge/discharge equipment with the maximum charge current specified by the manufacturer. If the manufacturer does not specify an appropriate charge current, then a charge rate of 1/3 C is used.
(f) After charging is initiated, the overcurrent specified by the manufacturer is supplied over the course of 5 seconds from the maximum charge current level to the over-current level. If the vehicle manufacturer does not supply an overcurrent level, a 10 Ampere over-current is supplied over 5 seconds. If charging is not terminated, the over-current supply is increased in steps of 10 Amperes.
(g) Charging at the over-current level is continued until one of the following occurs:
(1) The over-current protection control terminates the charge current; or
(2) The temperature gradient of the REESS is less than 4 °C through 2 hours from the first overcurrent input.
(h) After the charge current is terminated, if charge and discharge are permitted by the vehicle controls, a standard cycle is performed in accordance with S12.6.
(i) After the completion of the standard cycle or if the standard cycle was not performed, after charging is terminated, the vehicle is observed for 1 hour for evidence of electrolyte leakage, rupture, venting, fire, or explosion of the REESS.
(j) At the conclusion of the test, electrical isolation of the REESS is determined in accordance with S7.2 of this standard.
S12.4 Over-temperature test. The overtemperature test is conducted at ambient temperatures between 10 °C and 30 °C on a chassis-dynamometer with the vehicle REESS initially set between 90 to 95 percent SOC. For a vehicle with on-board energy conversion systems such as an internal combustion engine or a fuel cell, the fuel supply is set to allow operation for about one hour of driving. The following steps are conducted to evaluate the vehicle's high temperature protection controls:
(a) The cooling system of the REESS is disabled using manufacturer supplied information. For an REESS that will not operate if the cooling system is disabled, the cooling operation is significantly reduced. If manufacturer does not supply information to disable or significantly reduce the cooling system, methods such as crimping the liquid cooling hose, removing refrigerant fluid, or blocking cabin air intakes for air cooled REESS are applied.
(b) Temperature probes are connected to the REESS outer casing to monitor changes in REESS temperature. Temperature measurements may also be obtained through communication with the REESS control module.
(c) The vehicle is installed on a chassis dynamometer and the vehicle switch or device that provides power from the REESS to the electric power train is set to the activated position or the active driving possible mode.
(d) The vehicle is driven on the dynamometer using an appropriate vehicle manufacturer supplied drive profile and charging information for discharge and charge of the REESS to raise the REESS temperature to its upper boundary safe operating temperature within one hour. If an appropriate manufacturer-supplied drive profile is not available, the vehicle is repeatedly accelerated to 80 mph and then decelerated to 15 mph within 40 seconds. If the manufacturer does not supply a charge profile, then a charge rate greater than 1/3 C current is used.
(e) The discharge/charge procedure on the chassis-dynamometer is continued until one of the following occurs:
(1) The vehicle terminates the discharge/charge cycle;
(2) The temperature gradient of the REESS is less than 4 °C through 2 hours from the start of the discharge/charge cycle; or
(3) Three (3) hours have passed since the start of discharge/charge cycles.
(f) After the discharge and charge procedure is terminated, if charge and discharge are permitted by the vehicle controls, a standard cycle is performed in accordance with S12.6.
(g) After the completion of the standard cycle, or if the standard cycle is not performed, after the discharge and charge procedure is terminated, the vehicle is observed for 1 hour for evidence of electrolyte leakage, rupture, venting, fire, or explosion of the REESS.
(h) At the conclusion of the test, electrical isolation of the REESS is determined in accordance with S7.2 of this standard.
S12.5 External short circuit test. The short circuit test is conducted at ambient conditions with the vehicle REESS initially set between 90 to 95 percent SOC. The following steps are conducted to evaluate the vehicle's external short circuit protection controls:
(a) A breakout harness is connected to the REESS. The manufacturer must specify an appropriate location(s) and attachment point(s) to connect the breakout harness.
(b) Temperature probes are connected to the REESS outer casing to monitor changes in REESS temperature. Temperature measurements may also be obtained through communication with the REESS control module.
(c) The vehicle switch or device that provides power to the vehicle controls that manage REESS operations is set to the activated position.
(d) The short circuit contactor (with the contactors in open position) is connected to the breakout harnesses. The total resistance of the equipment to create the external short circuit (short circuit contactor and breakout harnesses) is verified to be between 2 to 5 milliohms.
(e) The short circuit contactor is closed to initiate the short circuit.
(f) The short circuit condition is continued until one of the following occurs:
(1) Short circuit current is terminated; or
(2) The temperature gradient of the REESS is less than 4 °C through 2 hours from the start of initiating the short circuit condition.
(g) After the short circuit current is terminated, if charge and discharge are permitted by the vehicle controls, a standard cycle is performed in accordance with S12.6.
(h) After the completion of the standard cycle, or if the standard cycle was not performed, after short circuit current is terminated, the vehicle is observed for 1 hour for evidence of electrolyte leakage, rupture, venting, fire, or explosion of the REESS.
(i) At the conclusion of the test, electrical isolation of the REESS is determined in accordance with S7.2 of this standard.
S12.6 Standard cycle. The standard cycle is conducted at ambient temperatures between 10 °C and 30 °C and starts with a standard discharge followed by a standard charge. The discharge and charge procedures would follow manufacturer supplied information. The charge procedure is initiated 15 minutes after discharge is terminated.
(a) If the manufacturer does not provide a discharge procedure, the vehicle is discharged with 1C current until discharge is terminated by vehicle controls.
(b) If the manufacturer does not provide a charge procedure, the vehicle is charged with 1/3 C current until terminated by vehicle controls.
S13. Warning in the case of thermal event in REESS. The vehicle shall provide a warning to the driver in the case of a thermal event in the REESS when the vehicle is in active driving possible mode. The thermal event warning system must monitor its own readiness. The warning shall activate within three minutes of the onset of the thermal event. The warning shall consist of auditory and visual signals that remain active for at least 5 minutes. For a vehicle with automated driving systems and without manually operated driving controls, the visual warning must be provided to all the front row occupants.
S14. Water exposure safety. Each vehicle to which the standard applies shall maintain electrical isolation as specified in S6.3.1 and S6.3.2 of this standard at these times:
(a) Just after exposure to water in each of the two tests specified below and with the vehicle still wet; and
(b) After a minimum of 24 hours after completing each of the tests specified in S14.1 and S14.2.
S14.1 Vehicle washing test. The vehicle is sprayed from any direction with a stream of freshwater from a standard test nozzle shown in figure 9 to this standard that has a nozzle internal diameter of 6.3 millimeters, delivery rate of 11.9 to 13.2 liters/minute, and water pressure at the nozzle between 30 kPa to 35 kPa.
(a) During the washing, the distance from the nozzle to the vehicle surface is 3.0 to 3.2 meters. The distance of the nozzle from the vehicle surface may be reduced, if necessary, to ensure the surface is wet when spraying upwards. The washing test duration per square meter of the vehicle surface area is 60 to 75 seconds, with a minimum total test duration of 3 minutes.
(b) The vehicle external surface, including the vehicle sides, front, rear, top, and bottom is exposed to the water stream. Border lines on the vehicle such glass seals, outline of opening parts (doors, windows, vehicle inlet cover), outline of front grille, and seals of vehicle lamps are exposed to the water stream from any direction.
(c) At the conclusion of the normal washing test, with the vehicle still wet, electrical isolation is determined in accordance with S7.2 of this standard.
S14.2 Driving through standing water test. The vehicle is driven through a wade pool of at least 10 centimeters but not more than 15 centimeters depth of freshwater for a distance of 500 meters at a minimum speed of 12 mph (20 km/h) but not more than 15 mph (24 km/h).
(a) If the wade pool is less than 500 m in length, then the vehicle shall be driven through it several times for a total distance of 500 m. The total time, including the period outside of the wade pool, shall be less than 10 minutes.
(b) At the conclusion of the standing water test, with the vehicle still wet, electrical isolation is determined in accordance with S7.2 of this standard.
Figures to FMVSS No. 305a
Figure 1. Voltage Measurements of the High Voltage Source
Figure 2. Measurement for V1 Voltage Between the Negative Side of the High Voltage Source and the Electrical Chassis
Figure 3. Measurement for V2 Voltage Between the Positive Side of the High Voltage Source and the Electrical Chassis
Figure 4. Measurement for V1' Voltage Across Resistor Between Negative Side of the High Voltage Source and Electrical Chassis
Figure 5. Measurement for V2' Voltage Across Resistor Between Positive Side of the High Voltage Source and Electrical Chassis
Figure 6. Marking of High Voltage Sources
Figure 7a. Access Probes for the Tests of Direct Contact Protection. Access Probe IPXXB (Top) and Access Probe IPXXD (Bottom)
Figure 7b. Jointed Test Finger IPXXB
Figure 8. Connection To Determine Resistance Between Exposed Conductive Parts of Electrical Protection Barrier and Electrical Chassis
Figure 9. Standard Nozzle for IPX5 Water Exposure Test
[89 FR 104352, Dec. 20, 2024]
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