CR1225 battery.36v lithium battery protection board wiring

　　The lithium battery protection board is to protect the charge and discharge of the series-connected lithium battery pack; when fully charged, it can ensure that the voltage difference between each single cell is less than the set value (generally ±20mV), achieving even charging of each single cell in the battery pack. , effectively improves the charging effect in series charging mode; simultaneously detects the overvoltage, undervoltage, overcurrent, short circuit, and overtemperature status of each single cell in the battery pack to protect and extend the service life of the battery; undervoltage protection enables each When a single battery is discharged, it can prevent the battery from being damaged due to over-discharge.

　　The finished lithium battery mainly consists of two parts, the lithium battery core and the protective plate. The lithium battery core is mainly composed of positive plate, separator, negative plate, and electrolyte; the positive plate, separator, and negative plate are wound or laminated, packaged, and filled with electrolyte , it is made into batteries after being packaged. Many people don’t know the function of the lithium battery protection plate. As the name suggests, it is used to protect the lithium battery. The function of the lithium battery protection plate is to protect the battery from being discharged, overcharged and overcharged. current, and there is output short circuit protection.

　　Working principle of lithium battery protection board

　　The reason why lithium battery (rechargeable type) needs protection is determined by its own characteristics. Since the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short-circuited, or charged and discharged at ultra-high temperatures, the lithium battery components will always appear with a delicate protective board and a current fuse.

　　The protection function of lithium batteries is usually completed by a protection circuit board and current devices such as pTC. The protection board is composed of electronic circuits and can accurately monitor the voltage and charge return circuit of the battery core at all times in an environment of -40°C to +85°C. Current, timely control the on and off of the current loop; pTC prevents severe damage to the battery in high temperature environments.

　　Ordinary lithium battery protection boards usually include control IC, 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 when everything is normal, so that the battery core is connected to the external circuit. When the battery core voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the battery core. Safety.

　　When the protection board is normal, Vdd is high level, Vss and VM are low level, DO and CO are high level. When any parameter of Vdd, Vss and VM changes, the level of DO or CO terminal will changes occur.

　　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. Over-discharge detection voltage: Under normal conditions, Vdd gradually decreases to the voltage between VDD-VSS when the DO terminal changes from high level to low level.

　　4. Over-discharge release voltage: In the over-discharge state, Vdd gradually rises to the voltage between VDD-VSS when the DO terminal changes from low level to high level.

　　5. Overcurrent 1 detection voltage: Under normal conditions, VM gradually rises to the voltage between VM and VSS when DO changes from high level to low level.

　　6. Overcurrent 2 detection voltage: Under normal conditions, VM rises from OV at a speed of more than 1ms and less than 4ms to the voltage between VM and VSS when the DO terminal changes from high level to low level.

　　7. Load short circuit detection voltage: Under normal conditions, VM starts from OV and rises to the voltage between VM and VSS when the DO terminal changes from high level to low level at a speed of more than 1μS and less than 50μS.

　　8. Charger detection voltage: In the over-discharge state, VM gradually drops from OV to the voltage between VM and VSS when DO changes from low level to high level.

　　9. Current consumption during normal operation: Under normal conditions, the current flowing to the VDD terminal (IDD) is the current consumption during normal operation.

　　10. Over-discharge current consumption: In the discharge state, the current (IDD) flowing through the VDD terminal is the over-discharge current consumption.

　　Lithium battery protection board wiring method

　　The third wire of some lithium-ion batteries is a temperature protection wire, and some are battery information verification wires (for example, if a non-original battery is replaced, an alarm will be prompted). Lithium-ion batteries are both batteries + protection boards. The 3 wires will only appear on the protection board, and the battery will always only have 2 wires. There are two types of lithium-ion batteries. Obviously the 3.7V one is non-aluminum iron phosphate and can be replaced directly.

　　Replacement is very simple (pay attention to the positive and negative poles):

　　1: Remove the packaging of the original battery, and then use a soldering iron to separate the protective plate and battery.

　　2: Similarly, remove the protective plate of your new battery and connect the battery to the old protective plate.

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