Design for reducing thermal spreads within a battery module

A battery pack assembly for providing electrical power comprising;

• a plurality of battery packs each including an upper stack and a lower stack extending parallel to one another and defining an air path therethrough for cooling,
• each of said stacks extending along an axis and including a plurality of cylindrical cells disposed end to end and each having walls and defining a cylinder and having a cathode and an anode at opposite ends of said cylinder and being stacked end to end in cathode-to-anode relationship with one another along said axis,
• each of said stacks being of equal length and containing equal numbers of said cells,
• said anodes of said cells in said upper stack facing in one direction and said anodes of said cells in said lower stack facing in the opposite direction,
• each of said battery packs including a casing having a front and a back for nesting said stacks one above the other and two end covers generally rectangular in shape with rounded corners with one of said end covers being disposed on said front and the other of said end caps being disposed on said back,
• each of said cells including a spacer being made of an insulating material and being cylindrical in shape and wrapping around said cylindrical wall of said cell adjacent to said anode end of said cell for creating a space between said cell and said casing longitudinally adjacent said spacer,
• said casing including an upper cylindrical section circling around a semi-cylindrical portion of said upper stack and extending along the length of said upper stack for creating an enclosed space around said semi-cylindrical portion of said upper stack,
• said casing including a reverse-L-shaped piece having a long leg extending tangentially from said cylindrical section to a short leg extending transversely and spaced from a remainder portion of said upper stack for creating an enclosed space around said remainder portion of said upper stack to define an air inlet chamber for supplying air to said enclosed space around said semi-cylindrical portion between said spacers to cool said cells,
• said upper cylindrical section and said reverse-L-shaped piece combining to completely enclose said upper stack with said upper cylindrical section enclosing said semi-cylindrical portion and said reverse-L-shaped piece enclosing said remainder portion,
• said air inlet chamber being defined by said long leg and said short leg and said cylindrical walls of said remainder portion of said upper stack,
• said air inlet chamber being generally right-triangular in cross section with said right-triangular cross section having two legs and a hypotenuse with said legs of said right-triangular cross section defined by said long leg and said short leg and said hypotenuse of said right-triangular cross section having a slight curvature and being defined by said cylindrical walls of said remainder portion of said upper stack,
• said air inlet chamber of said upper cylindrical section extending along the length of said upper stack,
• said remainder portion of said upper stack creating an exposed portion on each of said cells of said upper stack with said exposed portion of each of said cells being the portion of each cell adjacent and directly exposed to said air inlet chamber and enclosed by and spaced from said reverse-L-shaped piece,
• said upper cylindrical section defining a plurality of upper exits axially aligned in said cylindrical section of said casing diametrically opposite to said reverse-L-shaped for discharging air away from said space around said cells,
• said casing having a lower cylindrical section having an identical configuration to said upper cylindrical section and rotated one hundred eighty degrees from said upper cylindrical section,
• said remainder portion of said lower stack creating an exposed portion on each of said cells of said lower stack with said exposed portion of each of said cells being the portion of each cell adjacent and directly exposed to said air inlet chamber and enclosed by and spaced from said reverse-L-shaped piece,
• said short leg of said upper reverse-L-shaped piece being tangent to said lower cylindrical section and said short leg of said lower reverse-L-shaped piece being tangent to said upper cylindrical section with said air inlet chambers being open to one another,
• said lower cylindrical section defining a plurality of lower exits axially aligned in said cylindrical section of said casing diametrically opposite to said reverse-L-shaped piece thereof and opposite to said exits in said upper cylindrical section for discharging air away from said space around said cells in said lower cylindrical section,
• said air inlet chambers of said lower cylindrical section being engaged with a portion of each of said cells in said lower stack,
• each of said end covers including a positive terminal aligning with said anode of the outermost said cell of one stack and protruding through said end cover for contacting said anode and a negative terminal aligning with said cathode of the outermost said cell of the other stack and protruding through said end cover for contacting said cathode to transmit power from said respective stack of said cells,
• each said end covers disposed on said front end defining an entry for conveying air through said end cover and into said casing,
• a housing enclosing a plurality of said casings of said battery packs in a side by side relationship creating a channel being V-shaped between adjacent cylindrical sections of said casings and extending the length of said battery packs for conveying the air exiting said exits,
• an inlet manifold attached to said housing for supplying air to said air inlet chambers and over said battery packs,
• an outlet manifold attached to said housing for receiving air from said channels to discharge air from said exits,
• said inlet manifold extending along said front end covers of said battery packs and in spaced relationship to said front end covers of said battery packs,
• alternate battery packs having said positive terminal extending from said upper stack with the interleaved battery packs having said positive terminal extending from said lower stack,
• an inlet bus bar being sandwiched between said inlet manifold and said housing and including a plurality of connection wires for electrically connecting said positive terminal at one end of said battery pack to said negative terminal of the next adjacent battery pack for connecting said battery packs in series,
• an outlet bus bar being sandwiched between said outlet manifold and said housing and including a plurality of connection wires for electrically connecting said positive terminal to said negative terminal of each respective battery pack at the other end of said battery pack to complete the series connection of all said battery packs,
• said inlet bus bar defining a plurality of openings with each opening to two of said battery packs for conveying air through said inlet bus bar from said inlet manifold to said air inlet chambers of two adjacent battery packs,
• said openings each defined by a pair of semi-circular peripheries protruding downwardly and a pair of semi-circular peripheries protruding upwardly to cover said cylindrical sections,
• a first plurality of blocking pieces disposed in said air inlet chamber with each of said blocking pieces associated with one of said cells for reducing the size of said exposed portion of said respective cell to meter the flow of air into said respective cylindrical section around said respective cell,
• each of said blocking pieces extending longitudinally along the length of one of said cells and longitudinally from one spacer to the next successive spacer and being generally right-triangular in cross section with said right-triangular cross section having a hypotenuse and with said hypotenuse of said right-triangular cross section having a slight curvature,
• said curvature of said hypotenuse of said right-triangular cross section of said blocking piece defining a curved surface extending the length of said blocking piece,
• said curvature of said hypotenuse of said right-triangular cross section of said blocking piece being congruent to said curvature of said hypotenuse of said right-triangular cross section of said air inlet chamber,
• said hypotenuse of said right-triangular cross section of said blocking piece being shorter in length than said hypotenuse of said right-triangular cross section of said air inlet chamber,
• each of said curved surfaces of said blocking pieces being aligned with and spaced from said cylindrical walls of said exposed portion of said respective cell,
• each of said blocking pieces extending along the length of said respective cell and longitudinally from one spacer to the next successive spacer, and
• each of said curved surfaces of said blocking pieces decreasing in area from blocking piece to blocking piece and from front to back of said battery pack assembly and said respective exposed portions of said cells increasing in area from cell to cell and from front to back of said battery pack assembly.