What does "battery size" mean for lithium batteries?
Regulations governing lithium batteries are heavily influenced by their size. In fact, any exceptions to these regulations are also determined based on the battery’s capacity. So, in the world of lithium batteries, size truly does matter!
When it comes to shipping or transporting lithium batteries, the term "battery size" might pop up frequently. Interestingly, this term doesn’t refer to the physical dimensions of the battery. Instead, for lithium batteries, “"battery size" is all about the battery’s capacity or rating, which indicates how much electrical charge or energy the battery can store. Now, let's take a closer look at how size is determined.
Lithium battery size
Since lithium metal batteries use actual lithium metal or alloy to help generate energy and lithium-ion uses a chemical reaction to generate energy, they are rated differently:
- Lithium metal batteries are rated by the amount of lithium metal or alloy they contain by weight in grams.
- Lithium-ion batteries are rated by watt-hours.
Need additional information on lithium batteries? Check out this information on transporting lithium batteries.
Lithium metal content
Knowing the lithium metal content of the battery that you are shipping will help to determine how the battery must be packaged, marked, and labeled.
Often the lithium content for lithium metal batteries is not listed on the battery itself. If the lithium content is not listed on the battery, how do you find out the lithium content of your battery?
One way would be to check any product paperwork you may have, such as the Safety Data Sheet (SDS), specification information, or the test summary report that may be provided with the product.
Another way would be to calculate the lithium content yourself using the equation: Ah x 0.3 x number of cells = lithium content (Ampere-hour x 0.3 (It requires about 0.3 grams of lithium metal to produce 1 Ampere hour of power) x the number of cells the battery has = lithium content in grams).
Example: A battery that has 2.5 Ah and 6 cells would have a lithium metal content of 4.5 grams (2.5 x 0.3 x 6 = 4.5).
Watt-hour
Watt-hours are used to express how much energy (measured in watts) a lithium-ion battery can use in one hour. Knowing the watt-hour of the battery that you are shipping will help to determine how the battery must be packaged, marked, and labeled.
Newer lithium-ion batteries are required to have the watt-hour marked on the battery, so finding the watt-hour should be as simple as looking at the battery itself. However, how do you find the watt-hour on an older battery or on a newer battery where the watt-hour is rubbed off or missing?
One way to determine the watt-hour would be to check any product paperwork you may have, such as the Safety Data Sheet (SDS), specification information, or the test summary report that may be provided with the product.
Another way would be to calculate the watt-hour yourself using the equation: Ah x V = Wh (Ampere-hour x Volt = Watt-hour). Since most batteries already have the ampere-hours and volts marked on the battery, this formula should be easy to calculate.
Example: A battery that has 50 Ah and 12 V would have 600 Wh (50 x 12 = 600).
Key to remember: Grasping these fundamental aspects of lithium batteries size is crucial for anyone involved with shipping or transporting lithium batteries. Whether you are a manufacturer or carrier, understanding how to determine battery size will help ensure you comply with the regulations.