Thermal management of rechargeable batteries

• US 5,501,918 A
• Filed: 08/11/1994
• Issued: 03/26/1996
• Est. Priority Date: 02/08/1993
• Status: Expired due to Fees

• Current Assignee: C&D Technologies Incorporated (Angel Holdings LLC)
• Original Assignee: Globe-Union Inc.
• Inventors: Miller, Lawrence F., Gruenstern, Robert G., Bast, Ronald J., Aldecoa, Julin A.
• Primary Examiner(s): Willis, Jr., Prince
• Assistant Examiner(s): NUZZOLILLO, MARIA
• Application Number:
  US08/289,004
• Time in Patent Office: 593 Days
• Field of Search: 429/120, 429/148, 429/176, 429/72, 429/123, 429/151, 429/162
• US Class Current: 429/120
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/647 Prismatic or flat cells, e.g. pouch cells
• CPC Class Codes: H01M 10/6561 Gases
• CPC Class Codes: H01M 10/6566 Means within the gas flow to guide the flow around one or more cells, e.g. manifolds, baffles or other barriers H01M10/6565 takes precedence
• CPC Class Codes: H01M 10/6567 Liquids
• CPC Class Codes: H01M 50/103 prismatic or rectangular H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Thermal management of flat pack rechargeable batteries is accomplished by providing extensions on individual cell housing components, which extensions are connected to provide open air channels between individual cells. In an alternate embodiment of the invention, cells within the stack are filled with a thermally conductive liquid, such as a silica gel, to assist in heat dissipation from adjacent cells.

Claims

1. A battery stack, comprising:

a plurality of stacked, sealed cells, each cell containing a pair of positive and negative electrodes, a separator interposed between the electrodes, an electrolyte permeating the separator, a plastic casing enclosing each cell, and electrical connections for connecting the electrodes of each cell to associated terminals;

wherein at least one casing is spaced from the casing of an adjacent cell in the stack by plastic projections integrally molded on the at least one casing that leave an air space for heat dissipation between adjacent cells, the air space being open along an edge of the stacked cells, and the plastic projections are bonded to the adjacent cell casing such that the stack of cells forms an integral unit.

2. The battery stack of claim 1, wherein each cell contains positive and negative electrode plates having a separator interposed therebetween.

3. The battery stack of claim 2, wherein the battery is a lead-acid battery, such that the positive and negative plates are pasted with positive and negative lead active materials, respectively, and each cell contains a separate supply of an aqueous sulfuric acid electrolyte.

4. The battery stack of claim 2, wherein the positive electrode comprises a sheet of lead foil pasted on both sides with a positive lead active material, and the negative electrode comprises a pair of lead sheets disposed on opposite sides of the positive electrode, each negative electrode lead sheet having a layer of negative lead active material pasted thereon, and a pair of separators disposed on opposite sides of the positive electrode between the positive electrode and the negative electrode sheets.

5. The battery stack of claim 1, wherein the cell stack has a flat, rectangular shape, and the projections form at least one elongated slot along each side of the cell stack.

6. The battery stack of claim 1, wherein each cell is spaced from each adjacent cell by the plastic projections so that an air space is interposed between each pair of adjacent cells.

11. The battery stack of claim 6, wherein the plastic projections are bonded to oppositely-directed and aligned projections on an adjacent casing.

12. The battery stack of claim 11, wherein the plastic projections consist essentially of a thermoplastic material, and the projections are bonded together by vibration welding.

13. The battery stack of claim 1, wherein the plastic projections are disposed at the outer periphery of each cell and conform to the outer peripheral shape of each cell casing so that sides and ends of the resulting stack have a flat surface defined by end and side walls of each casing and outer surfaces of each projection, and elongated slots are formed by spaces between the projections.

14. The battery stack of claim 13, wherein the cell casings are rectangular, and the plastic projections comprise four L-shaped projections disposed at four corners of each casing.

15. The battery stack of claim 13, wherein all of the projections adjoin an outer peripheral wall of each cell casing and conform to the outer peripheral shape of each cell casing.

16. The battery stack of claim 13, wherein the electrical connections extend laterally through an end wall of each plastic casing.

17. The battery stack of claim 13, wherein all of the projections adjoin an outer peripheral wall of each cell casing and conform to the outer peripheral shape of each cell casing, and the electrical connections extend laterally through an end wall of each plastic casing, so that an interior space bounded by inner peripheral surfaces of the projections remains open.

18. The battery stack of claim 13, wherein each cell contains a lead foil substrate pasted on both sides with layers of a positive active material, a pair of separators disposed on either side of the lead foil substrate in contact with the positive material layers, and a pair of lead foil substrates each pasted on one side with a layer of a negative active material and disposed with the negative active material layers in contact with the separators on opposite sides of the lead foil substrate pasted on both sides with layers of a positive active material.

7. A method for assembling a flat pack battery comprising a plurality of stacked, sealed cells, each cell containing a pair of positive and negative electrodes, a separator interposed between the electrodes, an electrolyte permeating the separator, a plastic casing enclosing each cell, and electrical connections for connecting the electrodes of each cell to associated terminals, wherein at least one casing is spaced from the casing of an adjacent cell in the stack by plastic projections that leave an air space for heat dissipation between adjacent cells, the air space being open along an edge of the stacked cells, comprising the steps of:

forming casings having plastic projections thereon in alignable positions on the casing;

placing the projections of each casing into contact with corresponding, oppositely-directed projections of each adjacent casing to form aligned pairs of projections; and

bonding the pairs of projections together to form the air space between adjacent cells.

8. The method of claim 7, wherein the plastic projections consist essentially of a thermoplastic material, and the pairs of projections are bonded by vibration welding.

9. The method of claim 7, wherein the placing step further comprises placing flat end surfaces of each pair of aligned projections into face-to-face contact with each other.

10. The method of claim 8, wherein cells are lead-acid cells.