Lithium-ion battery cells must be thoroughly tested to eliminate leaks that might allow water or humidity to enter the cell, or cause electrolyte to leak out.
Why is battery leak testing important?
Reliable leak testing of battery cells is crucial because the highly flammable electrolytes they contain can spark fires. Even small amounts of humidity in a battery module can cause the system to short circuit, reduce service life and degrade performance, including a vehicle's driving range.
How difficult is a leak test for electric vehicle battery packs?
Leak testing electric vehicle battery packs is often more challenging than any tests performed at the component or subassembly level, due to the myriad of factors at play. In this blog post, Chuck Hagyard discusses these challenges and how to overcome them for an effective leak test.
Is a leaking battery a safety issue?
A leaking battery is more than just an inconvenience. In addition to causing a potential warranty claim or repair cost for the vehicle owner, it is a safety issue. The most common form of rechargeable battery for e-vehicles, lithium ion, can burst into flame or even explode if there is a leak.
How does a battery leak test work?
For instance, the cooling circuit is leak tested with air, while the battery cells are tested with either tracer gas or ionized air methods. “An in-process leak test is to check every battery subassembly, such as cells, cooling plates, cooling circuits, venting valves, trays and covers,” Dewailly points out.
What are the challenges of battery pack leak testing?
Below are two of the key challenges you are likely to encounter with battery pack leak testing and strategies to overcome them. Any kind of test that builds pressure (with air) inside the pack can cause the volume to expand like a balloon, which will increase the measured leak rate.
Why is leak testing important?
Leak testing plays a critical role in the assembly of battery cells, modules and packs. Batteries need to be leak-free and protected from humidity, water and other liquids for 10 years or more. Reliable leak testing of battery cells is crucial because the highly flammable electrolytes they contain can spark fires.