How to Judge the lithium battery pack performance? In general, we appraise a battery’sperformance by following ways.
1. Capacity: Battery capacity means theavailable charge from battery in certain discharging condition, that is theintegral of current times the time. It can affect the maximum working currentand working time of battery directly, and we usually use Ah or mAh to representit.
2. Discharge characteristic and internal resistance: Discharge characteristic means in certain systems, somecharacteristic like the stability of batter voltage, the levels of voltageplatform, the performance of high current discharging and so on. Those characteristicreflect the load capacity of battery.
Internal resistance includes ohmic resistance and electrochemicalpolarization resistance. When battery in high current discharging, it has anobvious influence on discharge characteristic.
3. Operating temperature range: Accordingto the operating environment of electric appliance and working conditions,battery work excellent in certain temperature range.
4. Storage performance: After storing forsome time, battery’s performance will be affected by some factors, leading toself discharge, electrolyte leakage, and short circuit, etc.
5. Cycle life (secondary battery): Cyclelife is the cycle times of secondary battery when its performance decreases tosome point (for example, 60% of initial capacity) in some charging and dischargingsystem.
6. Internal pressure and overcharge resistance performance (secondary battery): For some sealed secondary battery like Li-ionbattery, Ni-Cd battery, MH-Ni battery, there are some important indicators,that whether battery internal pressure reach equilibrium when charging in highcurrent, the level of equilibrium pressure, battery’s high current overchargingresistance performance, to measure battery’s performance good or bad.
If the battery’s internal pressure can’t reach equilibriumor excessive pressure, it will open the battery pressure-limiting device (suchas anti-explosion ball), causing air or electrolyte leakage, and leading tobattery failure. If the pressure-limiting device doesn’t work, it will causebattery shell cracking, even explosion.