Current collectors for improved safety

Patent metadata

Field	Value
Publication number	US-9847531-B2
Application number	US-201514955366-A
Country	US
Kind code	B2
Filing date	Dec 1, 2015
Priority date	Dec 1, 2015
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A battery electrode assembly includes a current collector with conduction barrier regions having a conductive state in which electrical conductivity through the conduction barrier region is permitted, and a safety state in which electrical conductivity through the conduction barrier regions is reduced. The conduction barrier regions change from the conductive state to the safety state when the current collector receives a short-threatening event. An electrode material can be connected to the current collector. The conduction barrier regions can define electrical isolation subregions. A battery is also disclosed, and methods for making the electrode assembly, methods for making a battery, and methods for operating a battery.

First claim

We claim:

1. A battery electrode assembly, comprising a current collector comprising conduction barrier regions having a conductive state in which electrical conductivity through the conduction barrier region is permitted, and a safety state in which electrical conductivity through the conduction barrier regions is reduced, the conduction barrier regions changing from the conductive state to the safety state when the current collector receives a short-threatening event; and, an electrode material connected to the current collector;
wherein the current collector comprises a plurality of electrical isolation subregions defined at least in part by the conduction barrier regions formed in the current collector, the isolation subregions having a conductive state in which the isolation subregions are not electrically isolated from other isolation subregions, and a safety state in which at least one isolation subregion is electrically isolated from at least one adjacent isolation subregion such that electrical conductivity through the adjacent isolation subregions in the safety state is reduced, the electrical isolation subregions changing from the conductive state to the safety state when respective conduction barrier regions defining the isolation subregions are changed from the conductive state to the safety state.

2. The battery electrode assembly of claim 1 , wherein the area of the isolation subregion is selected to limit the battery capacity that can be discharged through the isolation subregions to less than the capacity which causes sufficient Joule heating to initiate thermal runaway of a fully charged battery.

3. The battery electrode assembly of claim 2 wherein the dimension of the subregions is less than 1 cm 2 for Li-ion battery electrodes.

4. The battery electrode assembly of claim 3 , wherein the area of the isolation subregions is selected to limit discharge capacity to <10 mAh while in the safety state.

5. The battery electrode assembly of claim 1 , wherein in the safety state the resistance of the conduction barrier regions is at least 1000 times larger than the resistance in the conductive state.

6. The battery electrode assembly of claim 1 , wherein the conductive barrier regions are changed from the conductive state to the safety state by physical deformation of at least a portion of the current collector, the physical deformation of the current collector acting to cause physical deformation of at least one conduction barrier region of at least one isolation subregion to change the at least one isolation subregion from the conductive state to the safety state.

7. The battery electrode assembly of claim 6 , wherein the conduction barrier regions comprise voids in the current collector and the physical deformation is an expansion of the voids.

8. The battery electrode assembly of claim 6 , wherein the conduction barrier regions comprise transverse, non-connecting elongated regions, physical deformation of the current collector causing at least one of the transverse conduction barrier regions to be physically deformed and extended so as to intersect with an adjacent transverse conduction barrier region to cause at least one associated isolation subregion to change from the conductive state to the safety state.

9. The battery electrode of claim 8 , wherein the isolation subregions are rectangular.

10. The battery electrode of claim 8 , wherein the isolation subregions are triangular.

11. The battery electrode assembly of claim 1 , wherein the conduction barrier regions comprise voids extending through the current collector.

12. The battery electrode of claim 11 , wherein the conduction barrier regions comprise slits.

13. The battery electrode of claim 12 wherein the barrier regions comprise interconnecting slits.

14. The battery electrode of claim 13 , wherein the interconnecting slits are Y-shaped and the isolation subregions are triangular.

15. The battery electrode assembly of claim 1 , wherein at least two isolation subregions have different dimensions.

16. The battery electrode of claim 1 , wherein differently dimensioned isolation subregions are provided on the current collector as a gradient of at least one selected from the group consisting of the pattern and the size of the pattern of the isolation subregions.

17. The battery electrode assembly of claim 1 , wherein in the safety state an isolation subregion is electrically isolated from every adjacent isolation subregion.

18. The battery electrode assembly of claim 1 , wherein the current collector is metal.

19. The battery electrode of claim 1 , wherein the current collector comprises a metalized polymer.

20. The electrode assembly of claim 1 , wherein the electrode assembly comprises multilayer coatings of at least one selected from the group consisting of metal, carbon, ceramic and glass films on a polymer support.

21. The electrode assembly of claim 1 , wherein the current collector comprises multilayer coatings of at least one selected from the group consisting of metal, carbon, ceramic and glass films on a metal support.

22. The electrode assembly of claim 1 , wherein the current collector is comprised of bonding sections bonded together by at least one selected from the group consisting of adhesive and spot welds.

23. The battery electrode assembly of claim 1 , wherein the current collector comprises a polymer and the conduction barrier regions of the polymer have been rendered brittle.

24. The battery electrode assembly of claim 23 wherein the polymer is treated to be brittle and the polymer is selected such that its tensile strength is reduced by at least 10-fold after treatment.

25. The battery electrode assembly of claim 23 wherein the polymer is treated to be brittle and the elastic limit of the polymer after treatment is reduced at least 10-fold from the elastic limit before treatment.

26. The battery electrode assembly of claim 1 , wherein the conduction barrier region comprises perforations.

27. The battery of claim 1 , wherein in the electrical conductivity between adjacent isolation subregions in the safety state is eliminated.

28. A battery, comprising:
an anode electrode comprising an anode current collector and an anode electrode material;
a cathode electrode comprising a cathode current collector and a cathode electrode material;
at least one of the anode current collector and the cathode current collector comprising a current collector comprising conduction barrier regions having a conductive state in which electrical conductivity through the conduction barrier regions is permitted, and a safety state in which electrical conductivity through the conduction barrier regions is reduced, the conduction barrier regions changing from the conductive state to the safety state when the current collector receives a short-threatening event; and an electrolyte;
wherein the anode current collector and the cathode current collector comprise a plurality of electrical isolation subregions defined at least in part by conduction barrier regions formed in the current collector, the isolation subregions having a conductive state in which the isolation subregions are not electrically isolated from other isolation subregions, and a safety state in which at least one isolation subregion is electrically isolated from at least one adjacent isolation subregion such that electrical conductivity throu

Assignees

• Ut Battelle Llc

Inventors

• Abdelmalak Michael Naguib
• Allu Srikanth
• Dudney Nancy J
• Li Jianlin
• Simunovic Srdjan
• Wang Hsin

Classifications

• H01M4/661

  Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence) · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/70 Primary

  characterised by shape or form · CPC title