1. Design requirements of lithium battery for unmanned TT & C Ship:
The continuous working current of the unmanned TT & C ship is large, but the continuous working time of the battery is required to be at least one hour, and the charging time of the battery should be controlled within five hours; the battery requires instant high current discharge, and the battery should be waterproof; and the ship cannot return automatically due to over discharge of the battery should be avoided. For this reason, our company adopts the imported battery cell, which has the advantages of high energy ratio, light weight, small volume, high cycle life, high safety, high voltage and good consistency. The lithium battery pack adopts the special structure waterproof process design, and the customized BMS management system can prevent the battery from being unable to return without power. The specific parameters are as follows:
Nominal voltage: 25.9v
Nominal capacity: 20Ah
Charging voltage: 29.4V
Discharge current: 60A
Instantaneous discharge current: 100A
Discharge cut-off voltage: 21
Product size: φ 150 * 180mm
Charging temperature: 0 ~ 45 ℃
Discharge temperature: - 20 ~ 60 ℃
Battery shell: CNC aluminum profile
Waterproof grade: IP4X
2. Design scheme of lithium battery for unmanned TT & C Ship:
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 iron phosphate.
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: CNC aluminum shell.