BACKGROUND

The present invention generally relates to an energy storage system, and more particularly, to an energy storage module to be incorporated into a hybrid electric motor vehicle to store high voltage energy.

Vehicles incorporating electric motors require high voltage energy storage systems in order to properly power the motor. High voltage energy storage often encompasses multiple battery cells which are electrically connected together in series. Storage cells, when charging or discharging generate heat due to chemical reactions within the cells, as heat generation is a byproduct of electricity generation. When multiple battery cells are contained in close proximity, as in an array, the heat generated in each cell can become multiplicative throughout the system and can cause problems such as cell thermal runaway which can destroy the storage system. Additionally, for optimal energy efficiency, uniform temperature of the battery cells is preferred. Thus it is advantageous for such storage systems to include a cooling system to cool the battery cells.

Commonly, hybrid and electric energy storage cooling systems use an open system design which allows external air to reach the battery cells. Often these systems use convective heat transfer to reduce the temperatures of the batteries by passing air over the batteries which circulates from an external intake to an external exhaust. These systems are susceptible to problems caused by salt, dust, and other debris that can reach the battery cells by entering the air intake. Open cooling systems do not prevent salt fog or other corrosive materials from reaching the battery cells, even when a filter is used. Salt fog and foreign particles can cause corrosion and unwanted electrical leakage current paths or short circuits to exist in the storage system. Correspondingly, the system can cause a reduced battery cell life compared to a closed system. Open cooling systems can necessitate installation and use of drain plugs to remove foreign substances from the battery enclosure. Additionally, open cooling system designs add volume to the battery array system which causes problems with space-efficient original designs or hybrid retrofit applications.

The above problems as well as other problems with open cooling systems demonstrate a need in the field for alternative cooling systems for battery cell arrays such as various types of closed cooling systems.

SUMMARY

The energy storage systems described herein address several of the issues mentioned above as well as others. The energy storage systems include a housing containing an array of battery cells. The energy storage systems are closed systems such that the internal environments are hermetically sealed. The energy storage systems are designed to provide rapid and efficient heat transfer from the battery cells to the exterior of the housings.

In one example, an evaporator and air circulator are positioned within the housing. The evaporator can include of a series of evaporator coils integrated with a plurality of cooling fins. The air circulator can include a scroll-type fan. The air circulator and evaporator work cooperatively to enable rapid and efficient thermal energy transfer by providing a thermal energy flow path from the battery cells to a refrigerant located in the evaporator.

In other examples, a thermal transfer plate is positioned at the base of the battery cells. An evaporator or evaporator coils are positioned adjacent to the thermal transfer plate. The evaporator works cooperatively with the thermal transfer plate to enable rapid and efficient thermal energy transfer by providing a thermal energy flow path from the battery cells to a refrigerant located in the evaporator.

In another example, a thermal transfer plate is positioned at the base of the battery cells. A series of thermoelectric elements are positioned adjacent to the thermal transfer plate. The thermoelectric elements work cooperatively with the thermal transfer plate to enable rapid and efficient thermal energy transfer by providing a thermal energy flow path from the battery cells to a refrigerant located in the evaporator.

Further forms, objects, features, aspects, benefits, advantages, and examples of the present disclosure will become apparent from a detailed description and drawings provided herewith.

