Lithium ion batteries are widely used because of their light weight, high specific energy and long life. Low temperature lithium battery is made of special materials and technology, which is suitable for use in the cold environment below zero, and has excellent discharge capacity and working performance. It is generally required to work normally in the environment of - 40 ℃, with discharge capacity above 80%, and the minimum working temperature up to - 50 ℃.
1. Design of ultra-low temperature lithium battery
Low temperature battery refers to the lithium-ion battery whose working temperature is below - 40 ℃. It is mainly used in military aerospace, vehicle equipment, scientific research and emergency rescue, power communication, public safety, medical electronics, railway, ship, robot and other fields. According to the discharge performance, low temperature lithium batteries can be divided into energy storage low temperature lithium batteries and multiple rate low temperature lithium batteries. Low temperature lithium batteries are divided into military low temperature lithium batteries and industrial low temperature lithium batteries according to their application fields. According to its use environment, it can be divided into three series: civil low temperature battery, special low temperature battery and extreme environment low temperature battery. The specific parameters are as follows:
Nominal voltage: 11.1V
Nominal capacity: 5Ah
Charging voltage: 12.6V
Discharge current: 2A
Instantaneous discharge current: 6A
Discharge cut-off voltage: 9V
Product size: 40 * 70 * 60MM
Charging temperature: 0 ~ 45 ℃
Discharge temperature: - 40 ~ 60 ℃
Battery shell: ABS + PC / PVC simple package
2. Ultra-low temperature lithium battery design scheme:
1) BMS: it is mainly a protection circuit designed for rechargeable lithium battery pack. Due to the chemical characteristics of lithium battery, it is necessary to provide intelligent power calculation, overcharge, over discharge, short circuit, overcurrent and other protection functions to avoid burning, explosion and other hazards.
2) Protection IC (Protection IC): the main protection function chip of the design scheme, which can monitor the overcharge, over discharge, over current, short circuit and other functions of the cell online and constantly, so that the cell can work in a safe, stable and efficient range.
3) Temperature switch: mainly designed for temperature protection function. When the temperature of the battery itself reaches 70 ± 5 ℃ due to other abnormal problems, the temperature switch will act for temperature protection
4) Lithium ion cell: lithium ternary / lithium cobalt oxide.
5) Field effect transistor (MOSFET): MOSFET, in the protection circuit to play a switching role, always make the voltage at both ends of the load will not rise or fall, to ensure voltage stability.
6) Battery package: ABS + PC / PVC package.