Typically, for an off-grid or weak-grid consuming entity the main power source may include a hybrid engine-generator/battery system that can be used in backup situations. For example, if power from the commercial utility is lost, the engine-generator set can be activated to supply power to the facility. Start-up of the engine-generator set, however, takes time; therefore, the battery can provide power during this transitional time period. If the engine-generator set fails to start (e.g., runs out of fuel, suffers a mechanical failure, etc.), then the battery is able to provide power for an additional period of time. In this way, electrical energy production does not have to be drastically scaled up and down to meet momentary consumption. Rather, production can be maintained at a more constant level. Thus, electrical power systems can be more efficiently and easily operated at constant production levels.
Other battery applications may include a grid-connected energy storage system and/or motive-based storage. For example, such grid-connected battery systems can be utilized for peak shaving for commercial/industrial plants, buffering peak loads in distribution grids, energy trading, buffering solar power for night time, upgrade of solar/wind power generation, and/or any other suitable application.
In the battery applications described above, as well as any other suitable battery applications, it is important to maintain a uniform temperature between the cells of the battery pack or module. For modern designs, the cooling hardware flows air underneath the battery pack and then over the top. However, since the airflow is typically not sealed, some of the air flows over the front cells as the air enters the battery, thereby causing the front cells to cool more than the remaining cells. When the cells get colder, their internal electrical resistances increase, which can drive a higher voltage across the cells during recharge at a fixed current flow. This higher voltage can damage the cold cells, which can degrade the performance and/or reliability of the battery.
Before the energy storage device is either discharged or charged, a temperature difference exists between the cells due to the heater position and/or thermal resistance paths between the cells and ambient environment. Most batteries spend a large portion of their service life with this steady-state temperature difference, which is generally referred to as the float temperature gradient. The magnitude of this temperature difference typically stays the same during discharging and charging, and only grows when cooling air is forced into the battery interior, typically during recharge. Hence, the energy storage device spends most of its service life in the float temperature gradient state, which is seen during float and discharge. Minimizing the float temperature gradient can thus significantly increase the service life of an energy storage device,
Thus, it would be advantageous to provide a heat flux assembly for an energy storage device that minimizes the float temperature gradient and addresses the aforementioned issues.