Hermetically sealed lithium-ion secondary electrochemical cell

• US 6,245,464 B1
• Filed: 12/15/1998
• Issued: 06/12/2001
• Est. Priority Date: 09/21/1998
• Status: Expired due to Term

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Wilson Greatbatch Technologies, Inc.
• Inventors: Takeuchi, Esther S., Gan, Hong, Spillman, David M.
• Primary Examiner(s): Maples, John S.
• Application Number:
  US09/211,419
• Time in Patent Office: 910 Days
• Field of Search: 429/332, 429/176, 429/331, 429/326, 429/231.8, 429/218.1
• US Class Current: 429/332
• 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 10/0569 characterised by the solvents
• CPC Class Codes: H01M 2006/106 Elliptic wound cells
• CPC Class Codes: H01M 2300/0042 Four or more solvents
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 50/103 prismatic or rectangular H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/107 having curved cross-section, e.g. round or elliptic H01M50/103, H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/119 Metals
• CPC Class Codes: H01M 50/545 formed by the casing of the cells cup shaped terminals adapted for cells having curved cross-section H01M50/56
• CPC Class Codes: H01M 6/10 with wound or folded electrodes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A rechargeable alkali metal electrochemical cell, and preferably a lithium-ion secondary cell, constructed of low magnetic susceptibility materials, is described. The non-magnetic characteristics enable the secondary cell to be used within the confines of a Magnetic Resonance Imaging system. The cell includes an electrolyte solution comprising ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate.

Claims

1. A secondary electrochemical cell, which comprises:

a) a casing;

b) a negative electrode comprising a negative electrode active material which intercalates with an alkali metal;

c) a positive electrode comprising a positive electrode active material which intercalates with the alkali metal, wherein the negative electrode and the positive electrode are electrochemically associated with each other housed in the casing, and wherein a periphery of the positive electrode is completely bounded by a periphery of the negative electrode to prevent alkali metal from plating as the cell is repeatedly cycled between a charged and a discharged condition; and

d) an electrolyte solution activating the negative and positive electrodes, wherein the electrolyte comprises about 45% ethylene carbonate, about 22% dimethyl carbonate, about 24.8% ethylmethyl carbonate and about 8.2% diethyl carbonate, by volume.

2. The electrochemical cell of claim 1 wherein the casing is of a conductive material selected from the group consisting of Type 304 austenitic stainless steel, Type 304L austenitic stainless steel, Type 316 austenitic stainless steel, Type 316L austenitic stainless steel, titanium and alloys of titanium.

3. The electrochemical cell of claim 1 wherein the casing is of annealed stainless steel provided by heating the casing in an atmosphere selected from the group consisting of a vacuum, hydrogen, nitrogen, argon, helium, and mixtures thereof, to a temperature of about 1,040°

C. to about 1,090°

C., followed by cooling in the vacuum or an atmosphere selected from the group consisting of hydrogen, nitrogen, argon, helium, and mixtures thereof through a temperature range of about 780°

C. to about 450°

C. in about fifteen minutes, or less.

4. The electrochemical cell of claim 1 wherein the positive electrode is provided in a sheet form having spaced apart first and second ends meeting with first and second edges extending to opposed sides to provide the positive electrode having a width between the edges, a length between the ends and a thickness between the sides, and the negative electrode is provided in a sheet form having spaced apart first and second ends meeting with first and second edges extending to opposed sides to provide the negative electrode having a width between the edges, a length between the ends and a thickness between the sides, and wherein the negative electrode is provided side-by-side with the positive electrode having an intermediate separator such that the length and width of the negative electrode extend beyond the length and width of the positive electrode to provide the positive electrode bounded by the negative electrode.

5. The electrochemical cell of claim 1 wherein the alkali metal is lithium.

6. The electrochemical cell of claim 1 wherein the negative electrode active material is selected from the group consisting of coke, carbon black, graphite, acetylene black, carbon fibers, pitch carbon, synthetic carbon, mesocarbon microbeads, glassy carbon, and mixtures thereof.

7. The electrochemical cell of claim 1 wherein the negative electrode active material is contacted to a negative current collector selected from the group consisting of copper, nickel, nickel plated steel, stainless steel and titanium.

8. The electrochemical cell of claim 7 wherein the negative electrode current collection is in a form selected from the group consisting of foil, perforated screen, chemically etched screen and expanded screen.

9. The electrochemical cell of claim 1 wherein the negative electrode active material is mixed with a fluoro-resin binder.

10. The electrochemical cell of claim 1 wherein the positive electrode active material is selected from the group consisting of lithiated oxides, lithiated sulfides, lithiated selenides and lithiated tellurides of the group selected from vanadium, titanium, chromium, copper, molybdenum, niobium, iron, nickel, cobalt, manganese, and mixtures thereof.

11. The electrochemical cell of claim 1 wherein the positive electrode active material is contacted to an aluminum current collector.

12. The electrochemical cell of claim 11 wherein the aluminum positive electrode current collector is in a form selected from the group consisting of foil, perforated screen, chemically etched screen and expanded screen.

13. The electrochemical cell of claim 1 wherein the positive electrode active material is mixed with a fluoro-resin binder.

14. The electrochemical cell of claim 1 wherein the positive electrode active material is mixed with a conductive additive selected from the group consisting of acetylene black, carbon black, graphite, nickel powder, aluminum powder, titanium powder, stainless steel powder, and mixtures thereof.

15. An electrochemical cell, which comprises:

a) a casing of a material having a magnetic susceptibility of at least about 182×

10⁶, or greater;

b) a negative electrode which intercalates with lithium;

c) a positive electrode comprising a lithiated electrode active material, wherein the negative electrode and the positive electrode are electrochemically associated with each other housed in the casing; and

d) an electrolyte solution activating the negative and the positive electrodes, the electrolyte including a lithium metal salt dissolved in a quaternary, nonaqueous carbonate solvent mixture consisting of about 45% ethylene carbonate, 22% dimethyl carbonate, about 24.8% ethylmethyl carbonate and about 8.2% diethyl carbonate, by volume.

16. The electrochemical cell of claim 15 wherein the lithium metal salt is selected from the-group consisting of LiPF₆, LiBF₄, LiAsF₆, LiSbF₆, LiClO₄, LiAlCl₄, LiGaCl₄, LiNO₃, LiC(SO₂CF₃)₃, LiN(SO₂CF₃)₂, LiSCN, LiO₃SCF₂CF₃, LiC₆F₅SO₃, LiO₂CCF₃, LiSO₃F, LiB(C₆H₅)₄ and LiCF₃SO₃, and mixtures thereof.

17. A method for providing a secondary electrochemical cell, comprising the steps of:

e) providing a casing of a material having a magnetic susceptibility of at least about 182×

106, or greater;

f) providing a negative electrode which intercalates with an alkali metal;

g) providing a positive electrode comprising a positive electrode active material which intercalates with the alkali metal;

h) housing the negative and the positive electrodes inside the casing electrochemically associated with each other and wherein a periphery of the positive electrode is completely bounded by a periphery of the negative electrode to prevent alkali metal from plating as the cell is repeatedly cycled between a charged and a discharged condition; and

i) activating the negative and positive electrodes with an electrolyte comprising about 45% ethylene carbonate, about 22% dimethyl carbonate, about 24.8% ethylmethyl carbonate and about 8.2% diethyl carbonate, by volume.

18. The method of claim 17 including providing the casing of a conductive material selected from the group consisting of Type 304 austenitic stainless steel, Type 304L austenitic stainless steel, Type 316 austenitic stainless steel, Type 316L austenitic stainless steel, titanium and alloys of titanium.

19. The method of claim 17 including providing the casing of annealed stainless steel by heating the casing in an atmosphere selected from the group consisting of a vacuum, hydrogen, nitrogen, argon, helium, and mixtures thereof, to a temperature of about 1,040°

C. to about 1,090°

C., followed by cooling in the vacuum or an atmosphere selected from the group consisting of hydrogen, nitrogen, argon, helium, and mixtures thereof, through a temperature range of about 780°

C. to about 450°

C. in about fifteen minutes or less.

20. The method of claim 17 wherein the electrolyte includes an alkali metal salt selected from the group consisting of LiPF₆, LiBF₄, LiAsF₆, LiSbF₆, LiClO₄, LiAlCl₄, LiGaCl₄, LiNO₂, LiC(SO₂CF₃)₃, LiN(SO₂CF₃)₂, LiSCN, LiO₃SCF₂CF₃, LiC₆F₅SO₃, LiO₂CCF₃, LiSO₃F, LiB(C₆H₅)₄, LiCF₃SO₃, and mixtures thereof.

21. The method of claim 17 including providing the alkali metal as lithium.

22. The method of claim 17 including providing the negative electrode comprising a negative electrode active material selected from the group consisting of coke, carbon black, graphite, acetylene black, carbon fibers, pitch carbon, synthetic carbon, mesocarbon microbeads, glassy carbon, and mixtures thereof.

23. The method of claim 17 including contacting the negative active material to a negative electrode current collector selected from the group consisting of copper, nickel, nickel plated steel, stainless steel and titanium.

24. The method of claim 23 including providing the negative current collection in a form selected from the group consisting of foil, perforated screen, chemically etched screen and expanded screen.

25. The method of claim 17 including selecting the positive electrode active material from the group consisting of lithiated oxides, lithiated sulfides, lithiated selenides and lithiated tellurides of the group selected from vanadium, titanium, chromium, copper, molybdenum, niobium, iron, nickel, cobalt, manganese, and mixtures thereof.

26. The method of claim 17 including contacting the positive electrode active material to an aluminum current collector.

27. The method of claim 26 including providing the positive current collector in a form selected from the group consisting of foil, perforated screen, chemically etched screen and expanded screen.