Implantable battery having thermal shutdown separator

• US 20060166078A1
• Filed: 01/26/2005
• Published: 07/27/2006
• Est. Priority Date: 01/26/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Schmidt, Craig L., Skarstad, Paul M., Chen, Kaimin
• Granted Patent: US 8,945,753 B2
• Time in Patent Office: Days
• US Class Current: 429/62
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/457 comprising three or more layers
• CPC Class Codes: H01M 50/463 Separators, membranes or diaphragms characterised by their shape
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: H01M 6/16 with organic electrolyte H01M6/18 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 428/24998 Composite has more than two layers

Abstract

The present teachings include an electrochemical cell including an anode, a cathode, an electrolyte, a separator disposed between the cathode and anode, and a housing containing the anode, cathode, electrolyte, and separator. The separator can include a first sheet consisting essentially of a single layer material and a second sheet distinct from the first sheet. The second sheet can include an inner microporous layer laminated between two more outer layers. In some cells, the inner layer can have a transition temperature between a porous configuration and a substantially non-porous configuration that is between about 80 degrees C. and 150 degrees C., and in which the two more outer layers maintain their structural integrity to at least about 10 degrees C. greater than the first layer transition temperature.

Claims

1. An electrode assembly for a battery, comprising:

a first electrode;

a second electrode; and

a separator located between the first and second electrodes to prevent contact therebetween;

the separator comprising;

a first separator sheet disposed between the first electrode and the second electrode, the first sheet comprising two permeable outer layers each adhered to a microporous inner layer; and

a second separator sheet disposed between the first and second electrodes, the second sheet consisting essentially of a single permeable layer;

wherein the first sheet inner layer includes a first configuration porous to ion flow and a second configuration less porous to ion flow than the first configuration, and a first transition temperature between about 80 and 150 degrees C. at which the inner layer transforms from the first configuration to the second configuration, and in which the outer layers maintain structural integrity to a temperature of about 10 degrees C. higher than the first transition temperature.

2. An electrode assembly according to claim 1, in which the first electrode comprises an active cathode material, the second electrode comprises an active anode material, and in which the first sheet inner and outer layers and the second sheet single layer comprises a polymeric material.

3. An electrode assembly according to claim 2, in which the first sheet is interposed between the first electrode and the second sheet.

4. An electrode assembly according to claim 2, in which the first sheet is interposed between the second electrode and the second sheet.

5. An electrode assembly according to claim 2, in which the first and second electrodes are rolled together such that the first and second sheets form a spiral shape.

6. An electrode assembly according to claim 2, in which the first electrode includes a plurality of electrode plates and the second electrode includes a plurality of electrode plates, in which the first and second sheets include a plurality of discrete sheet pairs interposed between the first and second electrode plates.

7. A battery, comprising:

an anode including an active anode material in contact with an anode current collector;

a cathode including an active cathode material in contact with a cathode current collector; and

a separator disposed between the anode and the cathode;

an electrolyte; and

a housing containing the anode, cathode, separator, and electrolyte, the separator comprising a first sheet consisting essentially of a single layer material and a second sheet distinct from the first sheet;

wherein the second sheet comprises an inner microporous layer laminated between at least two additional outer layers.

8. A battery according to claim 7, in which the inner layer includes a transition temperature between a porous configuration and a substantially non-porous configuration that is between about 80 degrees C. and 150 degrees C., and in which the two more outer layers maintain their structural integrity to at least about 10 degrees C. greater than the first layer transition temperature.

9. A battery according to claim 8, in which the first sheet and the second sheet are substantially similar.

10. A battery according to claim 8, in which the first sheet and the second sheet are substantially different from each other.

11. A battery according to claim 8, in which the first sheet and the second sheet are all formed of polymeric materials.

12. A battery according to claim 8, in which the first sheet and the second sheet comprise polypropylene.

13. A battery according to claim 8, in which the second sheet inner layer comprises polyethylene.

14. A battery, comprising:

a plurality of anode layers;

a separator layer;

a plurality of cathode layers;

wherein the cathode and anode layers are configured as a stack having the separator disposed therebetween,

wherein the separator includes a first sheet and a second sheet, the first sheet consisting essentially of a unitary polymeric material having an electrical resistivity of less than about 500 ohms per square centimeter, and a second sheet;

wherein the second sheet comprises a microporous inner layer laminated between two more outer layers, wherein the microporous inner layer transforms to an essentially non-porous structure at a transformation temperature of at between about 80 and 150 degrees C., wherein the two more outer polymeric layers maintain structural integrity to a temperature of at least 10 degrees C. above the microporous polymeric inner layer transformation temperature.

15. A battery according to claim 14, in which the second sheet inner layer comprises a polymeric material.

16. A battery according to claim 15, in which the second sheet inner layer polymeric material comprises polyethylene.

17. A battery according to claim 14, in which the second sheet more outer layers comprise polypropylene.

18. A battery according to claim 14, in which the first sheet comprises a polymeric material.

19. A battery according to claim 14, in which the first sheet comprises polypropylene.