Cell cap assembly with recessed terminal and enlarged insulating gasket

• US 20100136421A1
• Filed: 07/07/2009
• Published: 06/03/2010
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Kohn, Scott Ira, Hermann, Weston Arthur
• Granted Patent: US 8,088,511 B2
• Time in Patent Office: Days
• US Class Current: 429/178
• CPC Class Codes: H01M 50/103 prismatic or rectangular H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/107 having curved cross-section, e.g. round or elliptic H01M50/103, H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/186 characterised by the disposition of the sealing members
• CPC Class Codes: H01M 50/193 Organic material
• CPC Class Codes: H01M 50/528 Fixed electrical connections, i.e. not intended for disconnection
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A simplified cell design is provided for a battery utilizing the 18650 form-factor in which the CID and PTC elements are eliminated, thereby reducing manufacturing cost and battery weight. To reduce the risk of shorting between the battery case and the battery terminal, the battery terminal is recessed relative to the top of the cell case and the insulating gasket positioned between the cell case and the cap assembly is designed to cover a large portion of the outer surface of the terminal element.

Claims

1. A battery having an 18650 form-factor, wherein said battery does not include a positive temperature coefficient (PTC) current limiting element, and wherein said battery does not include a current interrupt device (CID), the battery comprising:

a cell case having a cylindrical outer surface, a first end and a second end, wherein said first end is closed by a cell case bottom, and wherein said second end is comprised of a central open portion;

an electrode assembly contained within said cell case, wherein a first electrode of said electrode assembly is electrically connected to said cell case;

a terminal element mounted within said cell case, said terminal element closing said central open portion of said second end of said cell case, wherein an inner surface of said terminal element is electrically connected to a second electrode of said electrode assembly, wherein a portion of an outer surface of said terminal element serves as a battery terminal for said battery, and wherein said outer surface of said terminal element is recessed relative to an outermost edge portion of said second end of said cell case; and

an insulating gasket interposed between an inner surface of said cell case and said terminal element, wherein said insulating gasket includes an aperture, and wherein said aperture defines said battery terminal.

2. The battery of claim 1, wherein said insulating gasket is comprised of a first insulating member and a second insulating member, wherein said first insulating member covers at least a portion of said outer surface of said terminal element and includes said aperture, and wherein said second insulating member is interposed between said inner surface of said cell case and a peripheral edge of said terminal element.

3. The battery of claim 1, wherein said terminal element is comprised of an aluminum material.

4. The battery of claim 1, wherein said insulating gasket covers at least 50 percent of said outer surface of said terminal element.

5. The battery of claim 1, wherein said insulating gasket covers at least 75 percent of said outer surface of said terminal element.

6. The battery of claim 1, wherein said insulating gasket covers at least 90 percent of said outer surface of said terminal element.

7. The battery of claim 1, wherein said insulating gasket covers at least 95 percent of said outer surface of said terminal element.

8. The battery of claim 1, wherein said outer surface of said terminal element is substantially planar.

9. The battery of claim 1, wherein said insulating gasket is comprised of a material selected from the group of materials consisting of synthetic polymers, synthetic fluoropolymers, and polyimides.

10. The battery of claim 1, wherein said battery is a lithium ion battery.

11. The battery of claim 1, wherein said outer surface of said terminal element is scored.

12. The battery of claim 11, wherein said scoring on said outer surface of said terminal element forms a full circle.

13. The battery of claim 11, wherein said scoring on said outer surface of said terminal element forms an arc.

14. The battery of claim 1, wherein said inner surface of said terminal element is scored.

15. The battery of claim 14, wherein said scoring on said inner surface of said terminal element forms a full circle.

16. The battery of claim 14, wherein said scoring on said inner surface of said terminal element forms an arc.