Hot and cold shock test of lithium electric bicycle
As China enters the era of energy saving and emission reduction, e-bikes have become a better choice for short-distance transportation, and as the lithium battery of e-bike power unit, its performance response has always been the focus of research by manufacturers, once the lithium battery failure reaction will cause combustion, and if it is difficult to extinguish it will produce an instantaneous huge impact, or worse, it will explode and lead to safety accidents. The safety accident will be caused by the explosion.
Therefore, manufacturers in the process of manufacturing lithium batteries need to assess the safety of its different environments and reliability testing, and lithium battery environmental reliability is inseparable from the environmental testing equipment is the hot and cold shock chamber, the principle is to put the core into the high temperature test area, according to the standard rate of warming, and maintain high temperature so that its internal diaphragm melting, the formation of a large area of internal disconnection.
First, lithium battery thermal shock test method
1, test equipment: thermal shock test chamber
2, preparation: safety test before all battery packs need to be fully charged according to the standard (at a temperature of 23 ℃ +2 ℃ in the environment to 0.41 (A) charging, when the battery pack's terminal voltage reaches the charging limit voltage, changed to a constant voltage charging until the charging current is less than or equal to 0.041 (A), the longest time is not greater than 8h, stop charging) need to be placed in a fully charged 0.5 h ~ 1h and in the 24 h The test will be conducted within 24 h.
3, test steps: the first equipment to warm up to a temperature of 72 ℃ ± 2 ℃ after the sample placed in the test area after maintaining 4h, and then within 30 min cooling to 20 ℃ ± 2 ℃ and constant temperature of 2h, and then within 30 min cooling to -20 ℃ ± 2 ℃ and constant temperature of 4h, and finally within 30 min warmed up to 20 ℃ + 2 ℃ and constant temperature of 2 h, repeat the above steps for 4 times. After 5 high and low temperature shock cycles, the sample will be placed in a temperature of 20 ℃ ± 5 ℃ environment for 7 days.
4, the end of the test: visual inspection of the sample for deformation, cracking, liquid leakage, explosion or burning and other failure phenomena.