AGV lithium batteryThe types of core explosion can be summarized as external short circuit, internal short circuit, and overcharge. The external here refers to the outside of the battery cell, including short circuits caused by poor insulation design inside the battery pack.
When a short circuit occurs outside the AGV lithium battery and the electronic components fail to cut off the circuit, high heat will be generated inside the AGV lithium battery, causing part of the electrolyte to vaporize and expand the battery shell. When the internal temperature of the AGV lithium battery reaches 135 degrees Celsius, a good quality diaphragm paper will close the pores, the electrochemical reaction will terminate or almost terminate, the current will drop sharply, and the temperature will slowly drop, thereby avoiding the explosion. However, if the pore closing rate is too poor, or the pores of the diaphragm paper do not close at all, the battery temperature will continue to rise, more electrolyte will vaporize, the battery shell will be broken, and even the battery temperature will be raised to the point where the material will burn and explode. The internal short circuit is mainly caused by the burrs of the copper foil and aluminum foil piercing the diaphragm, or the dendrites of lithium atoms piercing the diaphragm. These tiny needle-like metals will cause micro short circuits. Since the needles are very thin and have a certain resistance value, the current may not be very large.
The burrs of copper and aluminum foil are caused during the production process. The observable phenomenon is that the battery leaks too quickly, and most of them can be screened out by the battery cell factory or assembly factory. Moreover, because the burrs are small, they are sometimes burned out, causing the battery to return to normal. Therefore, the probability of explosion caused by burr micro short circuit is not high. This statement can be supported by statistics, as each battery factory often has bad batteries with low voltage shortly after charging, but there are few explosions. Therefore, the explosion caused by internal short circuit is mainly caused by overcharging. Because after overcharging, the pole piece is full of needle-shaped lithium metal crystals, piercing points are everywhere, and micro short circuits occur everywhere. Therefore, the battery temperature will gradually rise, and the high temperature will gasify the electrolyte. In this case, whether the temperature is too high to cause the material to burn and explode, or the shell is broken first, allowing air to enter and violently oxidize the lithium metal, it will end in explosion.
However, the explosion caused by the internal short circuit caused by overcharging of the AGV lithium battery does not necessarily occur at the time of charging. It is possible that the battery temperature is not high enough to cause the material to burn, and the gas generated is not enough to break the battery shell, so the consumer stops charging and takes the phone out. At this time, the heat generated by the numerous micro-short circuits slowly raises the battery temperature, and after a period of time, the explosion occurs. The common description of consumers is that they find that the phone is very hot when they pick it up, and it explodes after throwing it away.
Combining the above types of explosions, we can focus on explosion prevention in three aspects: prevention of overcharging, prevention of external short circuits, and improvement of battery cell stability. Among them, overcharging prevention and external short circuit prevention belong to electronic protection, which is closely related to the AGV lithium battery system design and battery assembly. Improving battery cell stability is chemical and mechanical protection, which is closely related to the battery cell manufacturer.
If you want to choose a good AGV lithium battery, you might as well come to Shenzhen Jinchi Technology Co., Ltd. to have a look. Here we can produce lithium batteries for manufacturers who need customized lithium batteries and AGV lithium batteries.
