| Principle of over protection of lithium battery |
| Date：2021-01-13 Hits：515 |
| The protection circuit of Li ion battery consists of a protection IC and two power MOSFETs. The protection IC monitors the battery voltage and switches to the external power MOSFET in case of overcharge and discharge. Its functions include overcharge protection, over discharge protection and over-current / short circuit protection. Overcharge protection device. The principle of overcharge protection IC is as follows: when the external charger charges the lithium battery, in order to prevent the internal pressure rising caused by the temperature rise, it is necessary to stop charging. At this time, the protection IC needs to detect the voltage of the battery. When it arrives (assuming that the overcharge point of the battery is), that is, * overcharge protection, turn the power MOSFET from off to off, and then cut off charging. In addition, we must pay attention to the overcharge detection malfunction caused by noise, so as not to be judged as overcharge protection. Therefore, it is necessary to set the delay time, which should not be less than the noise duration. Over discharge protection device. When the discharge is too much, the performance of lithium battery will become worse due to the decomposition of electrolyte, and the charging times will be reduced. Using lithium battery to protect IC can avoid excessive discharge and protect battery. Overdischarge protection IC principle: in order to prevent the overdischarge state of lithium battery, assuming that the lithium battery is connected to the load, when the voltage of the lithium battery is lower than its overdischarge voltage detector (assumed to be), the overdischarge protection will be implemented, and the power MOSFET will be changed from open to open, and the discharge will be disconnected, so as to avoid the overdischarge phenomenon and make the battery in standby state, that is, only μ a overdischarge current. The protection circuit of the lithium-ion battery consists of a protection IC and two power MOSFETs. The protection IC monitors the battery voltage and switches to the external power MOSFET in case of overcharge and discharge. Its functions include overcharge protection, over discharge protection and over-current / short circuit protection. |
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