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.

What is claimed is: 
     
         1 . A battery pack housing configured to receive a plurality of electrochemical cells, the battery pack housing comprising a container that includes
 a base that includes an inner surface, an outer surface opposed to the inner surface, and a peripheral edge that joins the inner surface to the outer surface,   an outer wall that surrounds the peripheral edge and protrudes from the base in a direction that is normal to the inner surface of the base, the outer wall including a first portion, a second portion adjoining the first portion, a third portion adjoining the second portion and opposed to the first portion, and a fourth portion opposed to the second portion,   a first inner wall that extends between the first portion and the third portion, the first inner wall being fixed to each of the first portion and the third portion, and   a second inner wall that extends between the first portion and the third portion, is disposed between the first inner wall and the fourth portion, the second inner wall being movable relative to the outer wall such that a spacing of the second inner wall from the first inner wall can be changed.   
     
     
         2 . The battery pack housing of  claim 1 , wherein the first inner wall is spaced apart from the second portion and the fourth portion, whereby a gap exists between the first inner wall and the second portion. 
     
     
         3 . The battery pack housing of  claim 1 , wherein each of the first inner wall and the second inner wall is hollow and includes opposed inner and outer surfaces and ribs that extend between the opposed inner and outer surfaces, the ribs defining vacancies within each of the first inner wall and the second inner wall. 
     
     
         4 . The battery pack housing of  claim 1 , wherein a spacer is disposed between the second inner wall and the fourth portion. 
     
     
         5 . The battery pack housing of  claim 1 , wherein the second inner wall has an inner surface that is parallel to and faces the second portion, and an outer surface that faces the fourth portion, and at least a portion of the outer surface of the second inner wall is not parallel to the fourth portion. 
     
     
         6 . The battery pack housing of  claim 1 , wherein a portion of an outer surface of the outer wall is formed having outwardly protruding cooling ribs. 
     
     
         7 . The battery pack housing of  claim 1 , wherein the battery pack housing is formed of a non-electrically conductive material. 
     
     
         8 . The battery pack housing of  claim 1 , wherein
 the outer wall is formed of a first element, a second element formed separately from, and detachably connected to, the first element, and a latching member,   
       wherein
 the first element includes the first portion, the second portion and the third portion arranged in a U-shape, an inner surface of the first element including first surface features configured to receive the latching member, 
 the second element includes the fourth portion, and 
 an inner surface of the second element includes second surface features configured to receive the latching member and cooperate with first surface features to detachably connect the first element to the second element. 
 
     
     
         9 . The battery pack housing of  claim 8 , wherein the second element includes the second inner wall, and the second inner wall is parallel to and spaced apart from the fourth portion via a spacer. 
     
     
         10 . The battery pack housing of  claim 8 , wherein the latching member is a pin, wherein the first surface features include a first through opening and the second surface features include a second through opening, and the pin extends through both the first through opening and the second through opening. 
     
     
         11 . The battery pack housing of  claim 10 , wherein the second through opening is aligned with the first through opening along an axis normal to the inner surface of the base. 
     
     
         12 . A battery pack comprising a battery pack housing and electrochemical cells disposed in the housing, the housing comprising a container that includes
 a base that includes an inner surface, an outer surface opposed to the inner surface, and a peripheral edge that joins the inner surface to the outer surface,   an outer wall that surrounds the peripheral edge and protrudes from the base in a direction that is normal to the inner surface of the base, the outer wall including a first portion, a second portion adjoining the first portion, a third portion adjoining the second portion and opposed to the first portion, and a fourth portion opposed to the second portion,   a first inner wall that extends between the first portion and the third portion, the first inner wall being fixed to each of the first portion and the third portion, and   a second inner wall that extends between the first portion and the third portion, is disposed between the first inner wall and the fourth portion, the second inner wall being movable relative to the outer wall such that a spacing of the second inner wall from the first inner wall can be changed.   
     
     
         13 . The battery pack of  claim 12 , wherein the first inner wall is spaced apart from the second portion and the fourth portion, whereby a gap exists between the first inner wall and the second portion. 
     
     
         14 . The battery pack of  claim 12 , wherein each of the first inner wall and the second inner wall is hollow and includes opposed inner and outer surfaces and ribs that extend between the opposed inner and outer surfaces, the ribs defining vacancies within each of the first inner wall and the second inner wall. 
     
     
         15 . The battery pack of  claim 12 , wherein the second inner wall has an inner surface that is parallel to and faces the second portion, and an outer surface that faces the fourth portion, and at least a portion of the outer surface of the second inner wall is not parallel to the fourth portion. 
     
     
         16 . The battery pack of  claim 12 , wherein a spacer is disposed between the second inner wall and the fourth portion. 
     
     
         17 . The battery pack of  claim 12 , comprising a battery management device including electronics configured to monitor and control function of the electrochemical cells, the battery management device disposed in the container between the second inner wall and the fourth portion. 
     
     
         18 . The battery pack of  claim 12 , wherein the outer wall is formed of a first element, a second element formed separately from, and detachably connected to, the first element, and a latching member,
 wherein
 the first element includes the first portion, the second portion and the third portion arranged in a U-shape, an inner surface of the first element including first surface features configured to receive the latching member, 
 the second element includes the fourth portion, an inner surface of the second element includes second surface features configured to receive the latching member and cooperate with first surface features to detachably connect the first element to the second element. 
   
     
     
         19 . The battery pack of  claim 12 , wherein the electrochemical cells are arranged side-by-side within the housing, and an insulating sheet is disposed between each electrochemical cell. 
     
     
         20 . The battery pack of  claim 12 , wherein the electrochemical cells are supported on the base such that an outer surface of the cell housing directly contacts the base inner surface.