What is the principle of lithium-ion battery protection board and how the wiring is?

The principle of lithium-ion battery protection board The reason why lithium-ion batteries (rechargeable) need to be protected is determined by their own characteristics. Because the material of the lithium-ion battery itself determines that it cannot be overcharged, over-discharged, over-current, short-circuited, and ultra-high temperature charging and discharging, the lithium-ion battery components will always appear with a delicate protection board and a current fuse. The lithium-ion battery protection board is the charge and discharge protection of the series-connected lithium-ion battery pack; when fully charged, it can ensure that the voltage difference between the individual cells is less than the set value (generally ±20mV), so as to realize the protection of the individual cells of the battery pack. Equalizing charge effectively improves the charging effect in the series charging mode; at the same time, it detects the overvoltage, undervoltage, overcurrent, short circuit, and overtemperature status of each single cell in the battery pack to protect and extend the battery life; undervoltage protection Make each single battery prevent the battery from being damaged due to over-discharge when it is used for discharging. The protection function of lithium-ion battery is usually completed by the protection circuit board and current devices such as PTC. The protection board is composed of electronic circuits, which can accurately monitor the voltage and charge and discharge circuit of the cell at all times under the environment of -40℃ to +85℃ It can control the on and off of the current loop in time; PTC prevents severe damage to the battery under high temperature environment. Ordinary lithium-ion battery protection boards usually include control ICs, MOS switches, resistors, capacitors and auxiliary devices FUSE, PTC, NTC, ID, memory, etc. Among them, the control IC controls the MOS switch to turn on under all normal conditions to make the cell and the external circuit conduct, and when the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the cell’s Safety. When the lithium-ion battery protection board is normal, Vdd is high, Vss and VM are low, DO and CO are high. When any parameter of Vdd, Vss, VM is changed, the value of DO or CO is The level will change. 1. Overcharge detection voltage: Under normal conditions, Vdd gradually increases to the voltage between VDD and VSS when the CO terminal changes from high level to low level. 2. Overcharge release voltage: In the charging state, Vdd gradually decreases to the voltage between VDD and VSS when the CO terminal changes from low level to high level. 3. Overdischarge detection voltage: Under normal conditions, Vdd gradually decreases to the voltage between VDD and VSS when the DO terminal changes from high level to low level. 4. Overdischarge release voltage: In the overdischarge state, Vdd gradually rises to the voltage between VDD and VSS when the DO terminal changes from low level to high level. 5. Overcurrent 1 detection voltage: In the normal state, VM gradually rises to the voltage between VM and VSS when DO changes from high level to low level. 6. Overcurrent 2 detection voltage: In the normal state, VM rises from OV to the voltage between VM and VSS when the DO terminal changes from a high level to a low level at a speed of 1ms or more and 4ms or less. Lithium-ion battery protection board connection method Lithium-ion battery protection board connection methods generally used protection boards are nothing more than the negative pole plate, the negative pole splitter plate, and the positive pole plate. The other methods will not be repeated. In the process, there are many connection methods when testing the lithium-ion battery protection board on non-standard battery equipment. It is also worth familiarizing with the test connection. The simple process is as follows: 1. Place the device on a relatively horizontal desktop and adjust the stability of the device , Make it stable; 2. Ensure that the humidity of the equipment is in the range of 30~50%. If the humidity is too high, it is easy to cause leakage of the cabinet and electric shock; 3. Connect to a suitable power source (AC220V/0.1A) and turn on the main equipment power supply Button, turn on the respective power module button 4. Check whether the device can display normally and test normally. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete.