The corrosion speed depends on the composition of the plates¡ alloy, the higher store temperature the faster corrosion speed, the deeper discharge the more severity of corrosion. The salifiable of negative plates¡¯ sulfuricacid. During the normal operation, the PbSO4 grains on negative plates are small, so it is easy to resume as a velvet shape Pb, but in some time, there are PbSO4 produced in inner of battery which are difficulty to be deoxidized, so we name it as the salifiable of sulfuricacid. There are many reasons to cause the cathode salifiable, such as: It can't be charged in time after discharge, the battery has been stored in a long term to cause a serious self-discharge, the density of electrolyte is too high, the charging is not enough for long term and discharge under a high temperature for long term.