Intumescent battery housing

Abstract

A battery housing has a body and a lid mateable with the body. The body and the lid, when mated, provide a chamber dimensioned to hold at least one battery; and a venting passageway from the chamber. At least a portion of at least one of the body and the lid comprises an intumescent flame retardant material with an expansion ratio sufficient to drive gas from the chamber through the venting passageway and to seal the chamber when the material intumesces in the event of thermal runaway of a battery housed in the chamber.

1 .- 25 . (canceled) 
     
     
         26 . A battery pack, comprising:
 a housing with an internal cavity;   a plurality of cylindrical cells in a spatial arrangement within said internal cavity;   a vent hole for conveying gases away from said cylindrical cells in the event of thermal runaway;   intumescent material occupying spaces between said cells and said housing and blocking said vent hole, said intumescent material expanding to form a barrier between adjacent cells upon exposure to heat.   
     
     
         27 . The battery pack of  claim 26 , wherein intumescent material is configured such that pressure buildup resulting from thermal runaway overcomes said blocking. 
     
     
         28 . The battery pack of  claim 26 , wherein said housing comprises a cover, said cover comprising structurally weakened areas configured to break in response to elevated pressure within said internal cavity, thereby defining vent holes. 
     
     
         29 . The battery pack of  claim 27 , wherein said housing body defines a plurality of chambers in a grid, each chamber for receiving a cell. 
     
     
         30 . The battery pack of  claim 26 , comprising a fluid passage for transporting heat away from said cells. 
     
     
         31 . The battery pack of  claim 28 , wherein said fluid passage is positioned to receive heat from multiple ones of said plurality of cells. 
     
     
         32 . The battery pack of  claim 26 , wherein said intumescent material is configured to entomb a cell of said plurality of cells upon thermal runaway. 
     
     
         33 . The battery pack of  claim 26 , wherein said intumescent lining abuts said housing and at least some of said cells. 
     
     
         34 . A battery pack, comprising:
 a housing with an internal cavity;   a plurality of cylindrical cells in a spatial arrangement within said internal cavity;   intumescent material occupying spaces between said cells and said housing;   a blockage configured to be displaced by pressure in the event of thermal runaway, to open a venting outlet in said housing for conveying gases away from said cylindrical cells.   
     
     
         35 . The battery pack of  claim 34 , wherein said blockage comprises a weakened area of a cover of said housing, said weakened area configured to break in response to elevated pressure within said internal cavity. 
     
     
         36 . The battery pack of  claim 34 , wherein said blockage comprises an intumescent material blocking a vent hole. 
     
     
         37 . The battery pack of  claim 34 , wherein said housing body defines a plurality of chambers in a grid, each chamber for receiving a cell. 
     
     
         38 . The battery pack of  claim 34 , comprising a fluid passage for transporting heat away from said cells. 
     
     
         39 . The battery pack of  claim 38 , wherein said fluid passage is positioned to receive heat from multiple ones of said plurality of cells. 
     
     
         40 . The battery pack of  claim 39 , wherein said intumescent material is configured to entomb a cell of said plurality of cells upon thermal runaway. 
     
     
         41 . The battery pack of  claim 34 , wherein said intumescent lining abuts said housing and at least some of said cells. 
     
     
         42 . A battery pack, comprising:
 a housing body with an internal cavity;   a grid arrangement of cylindrical cells within said internal cavity;   intumescent material enwrapping cylindrical outer surfaces of said cells in abutting contact; and   at least one coolant conduit extending through said intumescent material in thermal contact with said grid arrangement of cylindrical cells, for removing heat.   
     
     
         43 . The battery pack of  claim 42 , wherein said housing body defines a plurality of chambers in a grid, each chamber for receiving a cell. 
     
     
         44 . The battery pack of  claim 42 , wherein said fluid passage is positioned to receive heat from multiple ones of said plurality of cells. 
     
     
         45 . The battery pack of  claim 42 , comprising a lid having a plurality of thin-walled regions configured to break in response to increased pressure, thereby venting said housing. 
     
     
         46 . The battery pack of  claim 45 , wherein said thin walled regions are located above respective ones of said cells. 
     
     
         47 . The battery pack of  claim 42 , wherein said intumescent material is configured to entomb a cell of said plurality of cells upon thermal runaway. 
     
     
         48 . The battery pack of  claim 42 , wherein said intumescent lining abuts said housing body and at least some of said cells.