The following methods can be used for inspection. If there are no following problems, it is normal. First, check whether there is any abnormality such as bulge, liquid leakage, burning loss, etc. through the appearance. When the battery failure cannot be judged by an intuitive way, open circuit voltage test and battery capacity test shall be carried out on the computer. The batteries that require computer operation, open circuit voltage test and battery capacity test can be divided into abnormal voltage batteries, over discharge batteries, abnormal discharge time batteries, charging and heating batteries, etc. Classification and detection methods of abnormal voltage batteries Generally, abnormal voltage batteries can be divided into two categories: voltage without current and voltage without current. For the battery with voltage and no current, it is generally judged as the manufacturing reason. This type of battery generally shows that there is voltage when using a multimeter to measure. When the computer is used for capacity detection, the battery discharge current drops rapidly, or the discharge capacity is short, generally less than 60 minutes, and the discharge is terminated. The battery without voltage and current is also called open circuit battery. The open circuit voltage of a single battery measured with a multimeter for this type of battery detection is 0V, which can be directly determined as open circuit. Or use a multimeter to measure the voltage of a single battery, use a car charger to charge a single battery to be tested for more than 10 minutes, and then use a resistance value of 1~1.5 ohms to discharge a single battery to be tested with a constant resistance, or discharge at a constant current of 10A~15A. If the battery terminal voltage is 0 V within 10 seconds of discharge, it is determined as open circuit. Classification and detection methods of overdischarge batteries Overdischarge batteries are generally divided into single overdischarge and group overdischarge. Generally, the above two types of overdischarged batteries can be judged by measuring the open circuit voltage. 

When the open circuit voltage of only one battery in the whole group is lower than 10.5V, and other voltages are higher than 10.5V, it can be judged as single overdischarge; When the open circuit voltage of the whole group of batteries is lower than 10.5V, or the total open circuit voltage of the whole group of batteries is lower than the total voltage of 10.5 * N (for example, the total voltage of the four batteries is lower than 10.5 * 4=42V), it can be judged as over discharge of the whole group. Classification and detection methods of batteries with abnormal discharge time The batteries with abnormal discharge capacity can be divided into two types: insufficient capacity of the whole group and large difference in capacity of the whole group. The battery capacity shall be tested, and the battery shall be charged and discharged for at least two times, and judgment shall be made according to the test results. After obtaining the discharge time, if the battery fails to meet the synchronization standard, or in terms of consistency (the difference in discharge time between the whole group of batteries), the renewal period is>10 minutes, and the replacement period is>15 minutes. As long as one point (or all of them) is met, it can be judged as backward. (The discharge time shall refer to the ambient test temperature.) Test method for rechargeable heating battery Test for rechargeable heating battery. It is only necessary to let the battery stand at room temperature after it is released alone, and then charge it. If the battery has serious heating phenomenon (temperature is higher than 50 ℃) at the initial stage of charging (within 4 hours of charging under the corresponding charging current).