DEFINITION OF VRLA BATTERY CAPACITY
Figure 6–1
117
Dynamic driving battery discharge test profile.
Battery Voltage (V)
13.5 13 12.5 12 11.5 0
1000
2000
3000
Discharge Time (secs)
tunately, it is difficult to keep the battery pack temperature, housing hundreds of cells at a constant temperature. This is owing to the fact that the batteries that are on the outermost edges have a greater surface for heat exchange while the batteries in the middle of the pack have the least available surface for exchange of heat. The stacking arrangement of the batteries in the pack leads to nonuniform temperatures, which in turn lead to nonuniform discharge and charge characteristics of the battery pack.
DEFINITION OF VRLA BATTERY CAPACITY As part of a battery pack configuration, a major problem experienced with the EVs is the premature decline of battery capacity, which ultimately leads to battery failure. The primary cause of the battery pack failure is owing to repeated nonuniform discharging and charging of the cells. Both the battery charging and discharging are highly dependent upon temperature. Owing to the large temperature difference between the coolest battery or batteries on the outer edge of the battery pack, and the hottest battery or batteries on the inner side of the battery pack, there is a corresponding variation in the available battery discharge capacity.
