A method of battery safety assessment

Abstract

The invention relates to a battery safety evaluation method, comprising the following steps: (1) charging a micro-short-circuit battery A and a normal battery B with y times the rated current I; (2) monitoring the temperature of each position of the two batteries during the charging process , select the highest temperature TAx of A and the temperature TBx of B at the corresponding position, and judge the gap between TAx and TBx; or monitor the calorific value QA and QB of two batteries; judge the gap between QA and QB; (3) increase the current I, repeat (2 ), (3) steps, until the gap reaches the requirements, stop the test; record the reference current Imax at this time, and the reference temperature or reference calorific value of B at the corresponding position; (4) use the reference current Imax test for the battery to be tested, and record the corresponding position The temperature T or the calorific value Q; if the temperature of the measured battery is compared with the reference temperature, or the gap between the calorific value and the reference calorific value meets the requirements; it is determined that the battery is a problem battery. It can quickly screen out problem batteries and effectively avoid safety problems caused by problem batteries.

Description

technical field [0001] The invention relates to a battery safety evaluation method. Background technique [0002] Due to its high specific energy and long cycle life, lithium-ion batteries are currently being used more and more in electric vehicles. However, frequent electric vehicle safety accidents have made everyone doubt the safety of electric vehicles, especially lithium-ion batteries for energy storage. Analyze the lithium-ion battery from the reaction principle and internal structure. The positive and negative electrodes of the lithium-ion battery are separated by a diaphragm in the middle. The diaphragm allows lithium ions to pass through and blocks electrons to pass through, thus ensuring the safety and continuity of the entire reaction process. conduct. However, once there is any problem with the diaphragm, it may cause direct contact between the positive and negative electrodes inside, which will cause an internal short circuit and a violent exothermic reaction,...

AI Technical Summary

Problems solved by technology

This kind of short circuit will not directly burn out the battery, but will reduce the performance of the battery cell or even cause safety problems in a short period of time (weeks or months), which will lead to the deterioration of the performance of the entire power system and even safety accidents.

[0003] Since the micro-short circuit of lithium-ion batteries is difficult to predict and analyze, there is no way to protect it through an external control circuit, which will cause high temperature and high resistance, and it is easy to cause a chain reaction of the battery pack. It is difficult to be found during initial testing or use. Therefore, it will leave a great potential safety hazard for later use. However, there is currently no effective monitoring method to judge the safety of the battery in advance.

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