Lithium-ion batteries play a key role in these vehicles, having the greatest charge capacity over competing battery technologies. Just like with fuel rails and other automotive components that require leak testing these batteries are tested with a helium hard-vacuum system.
VIC designs and builds custom tracer gas leak detection systems to test these power cells, several at a time. Each chamber is provided with its own product evacuation, charging, venting and valve scheme. A common dry vacuum pump with vacuum ballast provides the vacuum source. During the initial chamber evacuation, the system will perform a fitting-in-place check using a pressure transducer. This check is a pretest of seal integrity prior to evacuating the product and charging it with helium. After a successful vacuum decay test, the part is back-filled with helium to a specified pressure. After completion of all tests, the test part is vented to atmospheric pressure and re-evacuated to remove all residual helium before the part is unloaded.