1, sulphate: Friends who have seen the battery inside should understand that on the surface of the negative plate inside the lead-acid battery, there is a layer of white hard crystals attached, which can not be peeled off the surface of the negative plate into active substances after charging lead sulphate, which is sulphate, referred to as vulcanization. The appearance of vulcanization has a certain harm to the battery, which will lead to a series of problems such as short circuit, relaxation of active substances, deformation and fracture of grid plate. Lead-acid battery vulcanization destroys the ability of negative plate oxygen circulation, resulting in accelerated water loss. In this case, the proportion of sulfuric acid in lead-acid batteries will be higher, which leads to the vicious cycle of lead-acid batteries to continue to vulcanize. The degree of vulcanization of lead-acid batteries may be different, but the impact on the life of lead-acid batteries is universal.

2, water loss: in the charging and discharging process of lead-acid batteries, due to the existence of overpotential, gas appears in the charging and discharging process, which is the formation of gas caused by electrolytic use characterized by electrolyte movement; Taking 2V single battery as an example, after the battery is charged to 2.35v (25 ° C), it will enter the positive plate mass oxygen evolution state, and the negative plate has the oxygen recombination ability for the sealed battery. If the charging current is relatively large, the oxygen recombination reaction of the negative plate can not keep up with the speed of oxygen evolution, and the gas will open the exhaust valve and cause water loss. If the charging voltage reaches 2.42v (25 ° C), the negative plate of the battery will evolution hydrogen, and hydrogen can not be absorbed by the positive plate like the oxygen cycle, only to increase the air pressure of the battery chamber, and finally will be expelled from the air chamber to form water loss. Battery water loss is generally particularly serious in the case of overcharging.

3, thermal runaway battery thermal runaway is important in two cases, one is the lead-acid battery at constant voltage charging battery heat. Under the condition of constant voltage charging, the oxygen cycle current also participates in the charging current, so the rate of decline of the charging current slows down. The lead-acid battery heats up, causing the charging current to decline more slowly, and even the current to rise. The charging current in the use of battery heating, once the current rises, and added heat. In this way, the charging current will rise all the way to the current limit. The battery heats up and accumulates heat until the battery shell heats up and softens. When the battery is hot deformed, the internal pressure is high, so the battery is swollen. This is the battery thermal runaway and damage the battery. Another reason is vulcanization, which directly leads to the increase in the internal resistance of the battery, which further causes the lead-acid battery to charge and heat, and the heat makes the oxygen cycle current rise, so the battery with serious vulcanization has a great chance of thermal runaway. The higher the internal temperature of the battery, the larger the self-discharge, the higher the heat. Therefore, under the condition of high ambient temperature in summer, the temperature rise is also high due to the decrease of the gas extraction level. In this way, the probability of the colloidal lead-acid battery entering the thermal runaway is much greater.