SAFETY DEVICE FOR A SEALED ACCUMULATOR

• US 20130004809A1
• Filed: 06/29/2012
• Published: 01/03/2013
• Est. Priority Date: 07/01/2011
• Status: Active Grant

• Current Assignee: SAFT SA (Totalenergies Se)
• Original Assignee: SAFT SA (Totalenergies Se)
• Inventors: RIGOBERT, Gerard, MERMILLOD-BLONDIN, Luc, GAULET, Florian
• Granted Patent: US 9,099,715 B2
• Time in Patent Office: Days
• US Class Current: 429/56
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 50/30 Arrangements for facilitating escape of gases
• CPC Class Codes: H01M 50/317 Re-sealable arrangements
• CPC Class Codes: H01M 50/3425 in the form of rupturable membranes or weakened parts, e.g. pierced with the aid of a sharp member
• 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
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A sealed accumulator container (2) intended to contain an electrochemical bundle (9), the container comprising a wall forming a bottom (3) in an electrically conducting material comprising:

• • a peripheral portion (3a),
  • a cap (3c),
  • an embrittled portion (3b) delimiting the cap, joining the peripheral portion to the cap, adapted so as to break upon overpressure inside the container,

in which container is positioned an electrically conducting deformable membrane (10) electrically connecting electrodes of same polarity of an electrochemical bundle to the cap,

and in which container, overpressure causes deformation of the membrane, this deformation causing failure of the embrittled portion.

Claims

1. A sealed accumulator container intended to contain an electrochemical bundle, the container comprising a wall forming a bottom in an electrically conducting material, comprising:

a peripheral portion,

a cap,

an embrittled portion, delimiting the cap, joining the peripheral portion to the cap, adapted so as to break upon overpressure inside the container,

in which container is positioned an electrically conducting deformable membrane electrically connecting electrodes of a same polarity of an electrochemical bundle to the cap,

and in which container, an overpressure causes deformation of the membrane, this deformation causing failure of the embrittled portion.

2. The container according to claim 1, wherein a connecting part is positioned electrically connecting the electrodes of same polarity of the electrochemical bundle to the deformable membrane.

3. The container according to claim 1, wherein the deformable membrane has the shape of a disc and has a central portion and a peripheral portion, the limit between the central portion and the peripheral portion substantially coinciding with the embrittled portion, the peripheral portion of the deformable membrane substantially coinciding with the peripheral portion of the bottom of the container.

4. The container according to claim 2, wherein the deformable membrane comprises a central portion positioned in contact with the cap and a peripheral portion, electrically insulated from the connecting part and from the cap.

5. The container according to claim 2, wherein the deformable membrane and/or the connecting part are in aluminium.

6. The container according to claim 1, wherein the deformable membrane has a thickness comprised between 100 and 400 microns.

7. The container according to claim 1, wherein the deformable membrane is not openworked.

8. The container according to claim 1, wherein the deformable membrane maintains the container hermetically sealed after failure of the embrittled portion.

9. The container according to claim 1, wherein the deformable membrane comprises at least one embrittled portion capable of tearing in the case of overpressure inside the container, for example for an overpressure of about 15 bars.

10. The container according to claim 3, wherein the peripheral portion of the deformable membrane is covered with a sheath of an electrically insulating material.

11. The container according to claim 2, wherein the connecting part comprises a connecting portion in contact with the electrochemical bundle and a central portion in contact with the deformable membrane.

12. The container according to claim 11, wherein the connecting part comprises a bundle of identical flexible spiral-shaped lamellas, regularly distributed and connecting the central portion to the connecting portion.

13. The container according to claim 1, wherein the embrittled portion (3b) has a smaller thickness than those of the cap (3c) and of the peripheral portion (3a).

14. A sealed accumulator comprising:

the container according to claim 1,

an electrochemical bundle,

wherein failure of the embrittled portion of the wall of the bottom of the container is adapted for interrupting electric conduction via the cap between the deformable membrane and a current output terminal.

15. The accumulator according to claim 14, of the lithium-ion type.

16. A method for making an electric connection comprising the following steps:

a) making an electrochemical bundle available comprising at least one positive electrode and at least one negative electrode separated by a separator;

b) electrically connecting an electrically conducting deformable membrane with the electrodes of same polarity of the electrochemical bundle;

c) making available a container comprising a wall forming a bottom in an electrically conducting material comprising;

a peripheral portion,

a cap,

an embrittled portion delimiting the cap, joining the peripheral portion to the cap, adapted so as to break upon overpressure inside the container;

d) introducing into the container the electrochemical bundle and the deformable membrane so that the membrane is in contact with the cap.

17. The method for making an electric connection according to claim 16, wherein step b) comprises the two following sub steps:

i) electrically connecting a connecting part, other than an electrically conducting deformable membrane, onto the electrodes of same polarity of the electrochemical bundle; and

then

ii) electrically connecting the electrically conducting deformable membrane onto the connecting part.

18. The method according to claim 17, wherein between steps i) and ii), an electric insulating plastic film is wound around the electrochemical bundle while leaving free at least one portion of the connecting part.

19. The method according to claim 18, wherein the plastic film is a polyimide film.

20. The method according to claim 16, comprising after step d), a step for laser welding of the cap with the deformable membrane.

21. The method according to claim 17, comprising after step d), a step for laser welding the cap with the deformable membrane and the connecting part.