Why do electric vehicle batteries swell?

Everyone knows that the electric vehicle battery is a consumable product. What should I do if the electric vehicle battery swells during the charging process? Do you know the reason for the swelling of the electric vehicle battery? If you don’t know yet, then Let's take a look with the author. 1. The cause of overheating caused by battery swelling comes from the unreasonable battery selection and thermal design, or the temperature rise of the battery caused by the external short circuit, the loosening of the cable connector, etc., should be from the battery design and battery management. Aspect to solve. From the perspective of battery material design, materials that can prevent thermal runaway can be developed to block the reaction of thermal runaway; from the perspective of battery management, different temperature ranges can be predicted to define different safety levels to perform hierarchical alarms.　　2. Overcharging leads to swelling. 　　 'Overcharging leads to swelling' refers to the lack of circuit safety functions for overcharging in the electric vehicle battery management system itself, causing the battery's BMS to be out of control but still charging. For this type of overcharge, the solution is to find the fault of the rechargeable electric car battery first, which can be solved by the complete redundancy of the rechargeable battery; secondly, the battery management is unreasonable, for example, the voltage of each battery is not monitored. .　　　　3, internal short-circuit causes swelling　　 battery manufacturing impurities, metal particles, charge and discharge expansion and contraction, lithium evolution, etc. may cause internal short-circuit. This kind of internal short circuit occurs slowly and takes a very long time, and it is not known when it will cause the electric vehicle battery to swell.　　To solve the internal short circuit problem, we must first find a battery manufacturer with good product quality, select the battery and battery cell capacity; secondly, make a safety prediction of the internal short circuit, and find the monomer with internal short circuit before thermal runaway occurs. This means that the characteristic parameters of the monomer must be found, and the consistency can be started first. The battery is inconsistent, and the internal resistance is also inconsistent. As long as you find the monomer with variation in the middle, you can distinguish it. Previous: What should be paid attention to for the heat dissipation of electric vehicle batteries?