The ability of lithium battery protection board BMS for Lifepo4
Lithium battery protection board is mainly composed of maintenance IC (overvoltage maintenance) and MOS tube (overcurrent maintenance), which is used to protect the safety of lithium battery cells. Lithium batteries are widely used by people with large discharge current, low internal resistance, long life, no memory effect, etc. Lithium-ion batteries are prohibited from overcharging, overdischarging, and short-circuiting, otherwise it will cause the battery to catch fire, blast and other death defects Therefore, when using rechargeable lithium batteries, there will be a maintenance board to maintain the safety of the batteries.
1. Voltage protection capability
Overcharge protection board: The protection board must have the ability to prevent the cell voltage from exceeding the preset value. Over-discharge maintenance: The protection board must have the ability to prevent the cell voltage from falling below the preset value.
2. Current capability (over-current protection current, short-circuit protection)
As a safety protection device for lithium batteries, the protection board must not only work reliably within the normal operating current scale of the equipment, but also be able to act quickly when the battery is accidentally short-circuited or over-current, so that the batteries are protected.
definition: when the charging current is 500mA, the on-resistance of the MOS tube.
Due to the high operating frequency of communication equipment, the low bit error rate required for data transmission, and the steep rising and falling edges of the pulse train, the current output capability and voltage stability of the battery are required to be high, so the MOS switch of the protection board is turned on The time resistance should be small, and the single-cell battery protection board is usually "70mΩ. If it is too large, it will cause abnormal operation of the communication equipment, such as sudden disconnection of the mobile phone during a call, phone connection failure, noise, etc.
4. self-consumption current
definition: IC operating voltage is 3.6V, under no-load conditions, the operating current flowing through the protection IC is generally very small.
The self-consumption current of the protection board directly affects the standby time of the battery. Generally, the self-consumption current of the protection board is less than 10 microamps.
5. Mechanical function, temperature adaptability, antistatic ability
The protection board must be able to pass the sensation and impact test of the national standard rules; the protection board can work safely at 40 to 85 degrees, and can withstand the non-touch ESD static test of ±15KV.