Battery cap assembly with high efficiency vent

Patent metadata

Field	Value
Publication number	US-9692025-B2
Application number	US-201514973644-A
Country	US
Kind code	B2
Filing date	Dec 17, 2015
Priority date	Sep 7, 2011
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A battery cell design is disclosed that provides a predictable pathway through a portion of the cell (e.g., the cell cap assembly) for the efficient release of the thermal energy that occurs during thermal runaway, thereby reducing the chances of a rupture in an undesirable location. Furthermore the disclosed design maintains the functionality of the cell cap as the positive terminal of the cell, thereby having minimal impact on the manufacturability of the cell as well as its use in a variety of applications.

First claim

What is claimed as new and desired to be protected by Letters Patent of the United States is:

1. A method, comprising:
a) enclosing an electrode assembly for a battery cell within a closed case having a cylindrical shape and formed by a base, a cell cap assembly, and a side wall extending from the base to the cell cap assembly with the closed case defining a cavity therein containing the electrode assembly, the electrode assembly having a cathode and an anode with the electrode assembly constructed of materials that combust under a plurality of combustion conditions to generate a combustion material having a plurality of combustion material properties including a combustion material temperature and a combustion material pressure; and
b) defining an ejectment structure within the cell cap assembly, the ejectment structure concentrically oriented with a top plate of the cell cap assembly and
responsive to one or more particular combustion material properties of the plurality of combustion material properties directs the combustion material out of an ejectment aperture in a predetermined direction.

2. The method of claim 1 wherein the closed case includes a width dimension, a height dimension, and a length dimension, a largest of the dimensions generally parallel to the side wall of the closed case, wherein an electrical contact is provided at the top plate of the cell cap assembly and the electrical contact defines a first form factor for operation of the battery cell; the method further comprising:
c) disposing removably an adapter over both the cell cap assembly and the ejectment structure with the adapter reconfiguring the cell cap assembly to provide a second form factor different from the first form factor with the second form factor used for manufacturing and testing.

3. The method of claim 2 further comprising:
d) removing the adapter prior to use of the battery cell in a battery pack.

4. The method of claim 3 further comprising:
e) reusing the adapter to reconfigure another cell cap assembly of a subsequent battery cell and provide the second form factor for the subsequent battery cell.

5. The method of claim 4 wherein the subsequent battery cell includes the battery cell.

6. The method of claim 1 , wherein defining the ejectment structure comprises configuring the ejectment structure to mechanically respond to the particular combustion material properties to open the ejectment aperture of the ejectment structure at a first pressure and wherein the side wall is configured to mechanically be perforated by the combustion material at a second pressure that is greater than the first pressure.

7. The method of claim 1 wherein the ejectment structure includes a first material that melts at a first temperature and wherein the side wall includes a second material that melts at a second temperature higher than the first temperature.

8. The method of claim 7 wherein the first material includes aluminum and wherein the second material includes stainless steel.

9. The method of claim 7 wherein the cell cap assembly includes an exterior wall of the first material having a thickness configured to improve a mechanical failure response to the first temperature and wherein the exterior wall includes a mechanical reinforcement to improve structural integrity of the cell cap assembly.

10. The method of claim 7 wherein the cell cap assembly is attached to the side wall using an attachment structure and wherein the attachment structure includes the first material and the cell cap assembly includes the second material.

11. The method of claim 7 wherein the cell cap assembly is attached to the side wall using an attachment structure and wherein the attachment structure includes the second material and the cell cap assembly includes the first material.

12. The method of claim 1 further comprising providing a score in the cell cap assembly, the score configured to fail at a first pressure and wherein the side wall is configured to fail at a second pressure that is greater than the first pressure.

13. The method of claim 12 wherein the cell cap assembly includes an end wall having a generally circular perimeter, and wherein the score is provided as a mechanical scribe of a generally circular controlled depth on the end wall.

14. The method of claim 12 wherein the cell cap assembly includes an end wall retained to the top plate using one or more legs and wherein the score is provided as a mechanical scribe of a controlled depth on the one or more legs.

15. The method of claim 1 wherein an electrical contact of the closed case includes a three-sided contact plate and wherein the cell cap assembly defines the ejectment structure by a generally circular ejectment region with the three-sided contact plate overlying the generally circular ejectment region.

16. The method of claim 15 wherein the three-sided contact plate includes three generally linear edges or three generally arcuate edges.

17. The method of claim 15 wherein the three-sided contact plate includes a circular aperture generally centered over the generally circular ejectment region.

Assignees

• Tesla Motors Inc
• Tesla Inc

Inventors

• Leport Francisco
• Kohn Scott I
• King Orion A
• Prilutsky Alex

Classifications

• H01M50/152

  for cells having curved cross-section, e.g. round or elliptic (H01M50/15, H01M50/153 take precedence) · CPC title

• H01M50/167

  by crimping · CPC title

• H01M2200/20

  Pressure-sensitive devices · CPC title

• H01M2/022

  Electricity · mapped topic

• H01M2/1282

  Electricity · mapped topic