Li Ion Battery Protection IC-Definition And Working

Aug 13, 2020   Pageview:57

Lithium ion battery has been widely used in various power consumption industries for its superior performance and practicability. However, lithium-ion battery has some obvious defects. It has a long ability to withstand overcharge, over discharge and over-current, which may damage the battery and even cause safety accidents. In order to solve these problems, lithium-ion battery protection board was invented. In fact, lithium ion battery protection board can effectively prevent the overcharge, over discharge and over current of the battery.

What is li ion battery protection ic

Lithium ion battery protection ic is a chip installed on the protection board, and the battery protection board is an independent circuit. It can monitor the voltage and current of lithium-ion battery in real-time when charging and discharging. In case of abnormality, it will control the state of lithium-ion battery through control protection circuit. The working voltage of protection ic is generally the same as that of lithium-ion battery, which is about 3.6V. However, in order not to affect the normal operation of lithium-ion batteries, the current flowing through the protection ic must be very small (less than 10μa). Therefore, the protection ic chip and its protection circuit, as the safety protection devices of lithium battery, should not only work reliably within the normal working current range of the equipment, but also act quickly when the battery is accidentally short circuited or over-current, so that the battery cell can be protected.

The main function of lithium-ion protection circuit is to prevent battery overcharge, over discharge and over-current. These problems are destructive for lithium-ion batteries. The first is overcharge. Lithium ion battery belongs to rechargeable secondary battery. It can safely restore the voltage to about 4.2V when charging, but the voltage cannot be higher. Secondly, overcharging will lead to high battery voltage, which will damage the battery and even cause fire and other potential safety hazards. When the voltage of lithium-ion battery is reduced to about 3V, the discharge should be stopped. Excessive discharge will increase the pressure of the battery, which will shorten the cycle life of the battery. The last is over-current. Lithium ion batteries have a rated maximum current value. If the load current exceeds this current value during discharge, the battery may be damaged. Therefore, lithium ion battery protection circuit is very necessary for lithium-ion battery, and the core protection ic chip of the circuit can not be ignored.

24V Emergency Starting Power Supply,Low Temperature Large Current
Low Temperature Large Current 24V Emergency Starting Power Supply Battery specification: 25.2V28Ah (lithium battery) , 27V300F (supercapacitor pack) Charging temperature:-40℃~+50℃ Discharging temperature: -40℃~+50℃ Starting current: 3000A

How does li ion battery protection ic work

First of all, the protection ic will monitor the state of lithium-ion battery charging and discharging, which can accurately measure the working and charging voltage of lithium-ion battery. The protection ic will cut off and connect the battery circuit by controlling the MOSFETs switch on the lithium-ion battery protection circuit. Therefore, engineers need to consider the choice of MOSFET switch when designing protection IC. MOSFET with low RDS can effectively improve the efficiency of protection circuit, while MOSFET with low VT can effectively reduce the battery power consumption of protection circuit. In addition, setting the overvoltage protection threshold and over discharge protection threshold of protection IC is also an indispensable link in the design of protection IC.


Protection ic can monitor the status of lithium-ion battery in real-time when it is working and charging, and can react quickly in case of abnormal conditions. When the battery is charging, once the voltage at the battery end is too high (more than 4.2V), the protection ic will cut off the switch of the charging circuit in the MOS transistor. At this time, the battery can not continue charging, but can discharge normally. When the battery is discharging, once the battery terminal ground voltage is too low (lower than the set value of the minimum voltage), the protection ic will cut off the switch of the discharge circuit in the MOS transistor, so as to terminate the discharge, and the charging circuit will not be cut off. The protection circuit of lithium-ion battery is a good complement to the short board of this battery. This key technology has made great contribution to the promotion of lithium-ion battery.

Low Temperature High Energy Density Rugged Laptop Polymer Battery 11.1V 7800mAh
Low Temperature High Energy Density Rugged Laptop Polymer Battery Battery specification: 11.1V 7800mAh -40℃ 0.2C discharge capacity ≥80% Dustproof, resistance to dropping, anti - corrosion, anti - electromagnetic interference

Does every battery have li ion battery protection ic

According to the above analysis of protection ic and its protection circuit, it can be concluded that the safety and durability of lithium-ion battery with protection circuit is better than that without protection circuit. Therefore, when purchasing lithium-ion battery, consumers should also consider whether the battery has protection circuit and protection ic.

However, not all lithium-ion batteries on the market are equipped with protective circuits and protective ics. Because the installation of protection circuit means to spend more material cost and technical cost, many small-scale enterprises will omit the protection circuit of lithium-ion battery for the sake of battery sales and profits, so as to reduce the cost and price of battery as much as possible, and gain sufficient advantages in the market. However, the battery without protection circuit is easy to be damaged. The possibility of overcharge, over discharge, over current and overheating will be increased, which will lead to the increase of the probability of battery failure, which is also easy to cause safety hazards. Therefore, consumers should consider whether the battery has protection circuit when purchasing lithium-ion battery, instead of blindly choosing low-cost battery. In order to reduce the possibility of purchasing inferior batteries, consumers can choose batteries of famous brands, such as Samsung, Sony, etc. these manufacturers usually have the most advanced battery production process and the most complete battery production process. The batteries they produce will not be installed with protective circuit, and they are generally certified in terms of quality.

It is also worth noticing that not every lithium-ion battery should be equipped with protection circuit and protection IC. A battery pack can share one protection circuit, which will not burden the protection circuit or affect its function. Hope you can find this article useful.

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