Battery Pack

Abstract

A battery pack includes a housing and electrochemical cells disposed in the housing. The housing includes a container and a lid that closes an open end of the container. The container has a base, an outer wall the surrounds the base, and a first and a second inner wall disposed inside the outer wall. The first inner wall extends between, and is fixed to, a first portion and a third portion of the outer wall, and is spaced apart from a second portion and a fourth portion of the outer wall. The second inner wall extends between the first portion and the third portion, and is disposed between the first inner wall and the fourth portion. The second inner wall is movable relative to the outer wall such that spacing of the second inner wall from the first inner wall can be changed.

Description

BACKGROUND[0001]1. Field of the Invention[0002]The present invention relates to a battery pack for storage of electrochemical cells, including a battery pack housing having passive cooling features as well as features that minimize outer wall stress due to electrochemical cell growth.[0003]2. Description of the Related Art[0004]Battery packs provide power for various technologies ranging from portable electronics to renewable power systems and environmentally friendly vehicles. For example, hybrid electric vehicles (HEV) use a battery pack and an electric motor in conjunction with a combustion engine to increase fuel efficiency. Battery packs are formed of a plurality of battery modules, where each battery module includes several electrochemical cells. The cells are arranged in stacks and are electrically connected in series or in parallel. Likewise, the battery modules within a battery pack are electrically connected in series or in parallel.[0005]Some battery packs used with conve...

AI Technical Summary

Benefits of technology

[0010]In some aspects, a battery pack that produces a voltage of less than 60 V can be used as part of the power system of a hybrid electric vehicle, whereby it is possible to reduce power system costs and complexity. Because the voltage produced by the battery pack is less than 60 V, the components used to form the battery pack are less expensive.

[0011]The battery pack housing is configured to receive a plurality of prismatic cells. In some embodiments, the prismatic cells have a metal housing and thus may have an electric charge due to contact between the electrolyte disposed in the cell and the cell housing. The battery pack housing is formed of a material that is electrically nonconductive and thermally conductive. This can be compared to some conventional battery pack housings which are formed of an electrically conductive material such as metal, and in which insulating structures must be interposed between the prismatic cell housing and the battery pack housing, as well as between adjacent cells. By forming the battery pack housing of a non-electrically conductive material, it is possible for the cells to rest in direct contact with the housing without risk of forming an electrical short circuit. Since the insulating structures can be simplified, the battery pack housing can be reduced in size and the cost of materials and assembly can be reduced.

[0012]By forming the battery pack housing of a thermally conductive material, passive cooling of the battery pack housing and the cells disposed therein is enhanced. Advantageously, an outer surface of the battery pack housing includes cooling fins that further facilitate heat exchange with the ambient air.

[0013]The battery pack housing includes a container and a lid that closes an open end of the container. The container is formed having a dual-wall sidewall structure in which inner wall portions are spaced apart from the outer wall. In the illustrated embodiments, the container includes two inner

Problems solved by technology

Moreover, to accommodate the high voltage, the components in the electrical syst

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