1. Zero-voltage battery or combination battery has zero-voltage battery. The zero voltage of the battery is either unqualified product and does not reach the corresponding nominal capacity and voltage value when leaving the factory, or it is doomed to die and becomes zero due to long-term use, capacity exhaustion and voltage drop. Considering that the lithium battery has been used for a long time, such as more than a year, it may be discharged in the form of self-discharge to make the voltage zero, the current lithium battery protection scheme in the design requires that the battery can also be charged when the voltage is zero. Therefore, for the battery zero voltage has two kinds of difference: one is able to charge continue to use, the other is with no use value; In other words, the former capacity loss is reversible while the latter is irreversible. If a zero-voltage battery that cannot be charged is unfortunately designed into a lithium battery, it is possible to transmit the zero-voltage signal to the battery through the protection chip, thereby turning off the MOSFET and making the battery unable to be charged.
2. Battery connection error. This situation is less likely to occur, because rechargeable batteries or battery packs are generally required to be fully inspected when they leave the factory. Unless a batch of batteries are not fully inspected when they leave the factory, battery packs with wrong connections are among those not inspected. Of course, for informal manufacturers or individual assembly is another matter, the occurrence of connection errors can not be completely eliminated. Relatively speaking, the ni-MH battery pack full test rate is lower, the probability of this error may be a little larger.
3. Abnormalities occur to internal electronic components and protection circuits. This situation is generally after the battery has been used for a long time, the aging of electronic components, fall off will lead to abnormal battery charging, especially the electronic components integrated into the protection circuit after the occurrence of the above situation will directly affect the protection function of the circuit, so can not correctly guide the charging process.
