Efficient cell stack for cells with double screen sandwich cathodes

• US 20010049032A1
• Filed: 04/30/2001
• Published: 12/06/2001
• Est. Priority Date: 05/16/2000
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Wilson Greatbatch Technologies, Inc.
• Inventors: Gan, Hong
• Granted Patent: US 6,645,670 B2
• Time in Patent Office: Days
• US Class Current: 429/9
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: H01M 10/0431 Cells with wound or folded electrodes H01M10/045 takes precedence
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0563 Liquid materials, e.g. for Li-SOCl2 cells
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 10/286 Cells or batteries with wound or folded electrodes
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/0435 Rolling or calendering
• CPC Class Codes: H01M 4/24 Electrodes for alkaline accumulators
• CPC Class Codes: H01M 4/30 Pressing
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/5835 Comprising fluorine or fluoride salts
• CPC Class Codes: H01M 4/667 in the form of layers, e.g. coatings
• CPC Class Codes: H01M 6/10 with wound or folded electrodes
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

The present invention improves the performance of lithium electrochemical cells by providing a new electrode assembly based on a sandwich cathode design, but termed a double screen sandwich cathode electrode design. In particular, the present invention uses sandwich cathode electrodes which are, in turn, sandwiched between two half double screen sandwich cathode electrodes, either in a prismatic plate or serpentine-like electrode assembly. In a jellyroll electrode assembly, the cell is provided in a case-positive design and the outside round of the electrode assembly is a half double screen sandwich cathode electrode.

Claims

1. An electrochemical cell, which comprises:

a) a first cathode structure of a first cathode active material having a relatively high energy density but a relatively low rate capability sandwiched between first and second cathode current collectors, and a second cathode active material having a relatively low energy density but a relatively high rate capability contacted to the first and second cathode current collectors opposite the first cathode active material;

b) a first anode structure of an alkali metal contacted to opposite sides of a first anode current collector, wherein the first anode structure is in electrical association with the second cathode active material contacting the first cathode current collector;

c) a second cathode structure having a third cathode active material of a relatively high energy density but a relatively low rate capability contacted to one side of a third cathode current collector, and a fourth cathode active material of a relatively low energy density but a relatively high rate capability contacted to the other side of the third cathode current collector, wherein the fourth cathode active material is in electrical association with the first anode structure opposite the second cathode active material contacting the first cathode current collector; and

d) a nonaqueous electrolyte activating the anode and the cathode.

2. The electrochemical cell of

claim 1

wherein the first and third cathode active materials are selected from the group consisting of CF_x, Ag₂O, Ag₂O₂, CuF, Ag₂CrO₄, MnO₂, SVO, and mixtures thereof.

3. The electrochemical cell of

claim 1

wherein the second and fourth cathode active materials are selected from the group consisting of SVO, CSVO, V₂O₅, MnO₂, LiCoO₂, LiNiO₂, LiMnO₂, CuO₂, TiS, Cu₂S, FeS, FeS₂, copper oxide, copper vanadium oxide, and mixtures thereof.

4. The electrochemical cell of

claim 1

wherein the first and third cathode active materials are CF_x and the second and fourth cathode active materials are SVO.

5. The electrochemical cell of

claim 1

wherein the first cathode structure has the configuration:

SVO/current collector/CF_x/current collector/SVO.

6. The electrochemical cell of

claim 1

wherein the second cathode structure has the configuration:

CF_x/current collector/SVO.

7. The electrochemical cell of

claim 1

further including a second anode structure of the alkali metal contacted to opposite sides of a second anode current collector, wherein the second anode structure is in electrical association with the second cathode active material contacting the second cathode current collector.

8. The electrochemical cell of

claim 7

further includes a third cathode structure having a fifth cathode active material of a relatively high energy density but a relatively low rate capability contacted to one side of a fourth cathode current collector, and a sixth cathode active material of a relatively low energy density but a relatively high rate capability contacted to the other side of the fourth cathode current collector, wherein the sixth cathode active material is in electrical association with the second anode structure opposite the second cathode active material contacting the second cathode current collector.

9. The electrochemical cell of

claim 8

wherein the first, third and fifth cathode active materials are selected from the group consisting of CF_x, Ag₂O, Ag₂O₂, CuF, Ag₂CrO₄, MnO₂, SVO, and mixtures thereof.

10. The electrochemical cell of

claim 8

wherein the second, fourth and sixth cathode active materials are selected from the group consisting of SVO, CSVQ, V₂O₅, MnO₂, LiCoO₂, LiNiO₂, LiMnO₂, CuO₂, TiS, Cu₂S, FeS, FeS₂, copper oxide, copper vanadium oxide, and mixtures thereof.

11. The electrochemical cell of

claim 8

wherein the first, third and fifth cathode active materials are CF_x and the second, fourth and sixth cathode active materials are SVO.

12. The electrochemical cell of

claim 8

wherein the second and third cathode structures have the configuration:

CF_x/current collector/SVO.

13. The electrochemical cell of

claim 1

wherein the cathode structure has the configuration:

SVO/current collector/SVO/CF_x/SVO/current collector/SVO.

14. The electrochemical cell of

claim 1

wherein the first, second and third current collectors are selected from the group consisting of stainless steel, titanium, tantalum, platinum, gold, aluminum, cobalt nickel alloys, nickel-containing alloys, highly alloyed ferritic stainless steel containing molybdenum and chromium, and nickel-, chromium-, and molybdenum-containing alloys.

15. The electrochemical cell of

claim 1

wherein the first, second and third current collectors are titanium having a coating selected from the group consisting of graphite/carbon material, iridium, iridium oxide and platinum provided thereon.

16. The electrochemical cell of

claim 1

wherein the anode is lithium, the first and third cathode active materials are CF_x, the second and fourth cathode active materials are SVO and the first, second and third current collectors are titanium.

17. The electrochemical cell of

claim 1

wherein the electrolyte has a first solvent selected from an ester, a linear ether, a cyclic ether, a dialkyl carbonate, and mixtures thereof, and a second solvent selected from a cyclic carbonate, a cyclic ester, a cyclic amide, and mixtures thereof.

18. The electrochemical cell of

claim 17

wherein the first solvent is selected from the group consisting of tetrahydrofuran (THF), methyl acetate (MA), diglyme, trigylme, tetragylme, dimethyl carbonate (DMC), 1,2dimethoxyethane (DME), 1,2-diethoxyethane (DEE), 1-ethoxy,2-methoxyethane (EME), ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, diethyl carbonate, dipropyl carbonate, and mixtures thereof, and the second solvent is selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate, acetonitrile, dimethyl sulfoxide, dimethyl, formamide, dimethyl acetamide, γ

-valerolactone, γ

-butyrolactone (GBL), N-methyl-pyrrolidinone (NMP), and mixtures thereof.

19. The electrochemical cell of

claim 1

including a lithium salt selected from the group consisting of LiPF₆, LiBF₄, LiAsF₆, LiSbF₆, LiClO₄, LiO₂, LiAlCl₄, LiGaCl₄, LiC(SO₂CF₃)₃, LiN(SO₂CF₃)₂, LiSCN, LiO₃SCF₃, LiC₆F₅SO₃, LiO₂CCF₃, LiSO₆F, LiB(C₆H₅)₄, LiCF₃SO₃, and mixtures thereof.

20. The electrochemical cell of

claim 1

wherein the electrolyte is 0.8M to 1.5M LiAsF₆ or LiPF₆ dissolved in a 50:

50 mixture, by volume, of propylene carbonate as the first solvent and 1,2-dimethoxyethane as the second solvent.

21. The electrochemical cell of

claim 1

wherein the anode is lithium and the cathode has the configuration:

SVO/current collector/Ag₂O, with the SVO facing the lithium anode.

22. An electrochemical cell, which comprises:

a) a first cathode structure of a first cathode active material having a relatively high energy density but a relatively low rate capability sandwiched between first and second cathode current collectors, and a second cathode active material having a relatively low energy density but a relatively high rate capability contacted to the first and second cathode current collectors opposite the first cathode active material;

b) a first anode structure of an alkali metal contacted to opposite sides of a first anode current collector, wherein the first anode structure is in electrical association with the second cathode active material contacting the first cathode current collector;

c) a second cathode structure having a third cathode active material of a relatively high energy density but a relatively low rate capability contacted to one side of a third cathode current collector, and a fourth cathode active material of a relatively low energy density but a relatively high rate capability contacted to the other side of the third cathode current collector, wherein the fourth cathode active material is in electrical association with the first anode structure opposite the second cathode active material contacting the first cathode current collector;

d) a second anode structure of the alkali metal contacted to opposite sides of a second anode current collector, wherein the second anode structure is in electrical association with the second cathode active material contacting the second cathode current collector;

e) a third cathode structure having a fifth cathode active material of a relatively high energy density but a relatively low rate capability contacted to one side of a fourth cathode current collector, and a sixth cathode active material of a relatively low energy density but a relatively high rate capability contacted to the other side of the fourth cathode current collector, wherein the sixth cathode active material is in electrical association with the second anode structure opposite the second cathode active material contacting the second cathode current collector; and

f) a nonaqueous electrolyte activating the anode and the cathode.

23. The electrochemical cell of

claim 22

wherein the first, third and fifth cathode active materials are selected from the group consisting of CF_x, Ag₂O, Ag₂O₂, CuF, Ag₂CrO₄, MnO₂, SVO, and mixtures thereof.

24. The electrochemical cell of

claim 22

wherein the second, fourth and sixth cathode active materials are selected from the group consisting of SVO, CSVO, V₂O₅, MnO₂, LiCoO₂, LiNiO₂, LiMnO₂, CuO₂, TiS, Cu₂S, FeS, FeS₂, copper oxide, copper vanadium oxide, and mixtures thereof.

25. A method for powering an implantable medical device, comprising the steps of:

a) providing the medical device;

b) providing an electrochemical cell comprising the steps of;

i) providing an anode of an alkali metal;

ii) providing a first cathode structure of a first cathode active material having a relatively high energy density but a relatively low rate capability sandwiched between first and second cathode current collectors, and a second cathode active material having a relatively low energy density but a relatively high rate capability contacted to the first and second cathode current collectors opposite the first cathode active material;

iii) providing a first anode structure of an alkali metal contacted to opposite sides of a first anode current collector, wherein the first anode structure is in electrical association with the second cathode active material contacting the first cathode current collector;

iv) providing a second cathode structure having a third cathode active material of a relatively high energy density but a relatively low rate capability contacted to one side of a third cathode current collector, and providing a fourth cathode active material of a relatively low energy density but a relatively high rate capability contacted to the other side of the third cathode current collector, wherein the fourth cathode active material is in electrical association with the first anode structure opposite the second cathode active material contacting the first cathode current collector; and

v) activating the anode and cathode with a nonaqueous electrolyte; and

c) electrically connecting the electrochemical cell to the medical device.

26. The method of

claim 25

including selecting the first and third cathode active materials from the group consisting of CF_x, Ag₂O, Ag₂O₂, CuF, Ag₂CrO₄, MnO₂, SVO, and mixtures thereof.

27. The method of

claim 25

including selecting the second and fourth cathode active materials from the group consisting of SVO, CSVO, V₂O₅, MnO₂, LiCoO₂, LiNiO₂, LiMnO₂, CuO₂, TiS, Cu₂S, FeS, FeS₂, copper oxide, copper vanadium oxide, and mixtures thereof.

28. The method of

claim 25

wherein the anode is lithium, the first and third cathode active materials are CF_x, and the second and fourth cathode active materials are SVO.

29. The method of

claim 25

including providing the first cathode structure having the configuration:

SVO/current collector/CF_x/current collector/SVO.

30. The method of

claim 25

including providing the second cathode structure having the configuration:

CF_x/current collector/SVO.