Method of preparing electrochemical cells

• US 5,759,215 A
• Filed: 11/17/1995
• Issued: 06/02/1998
• Est. Priority Date: 11/17/1995
• Status: Expired due to Fees

• Current Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Original Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Inventors: Masuda, William
• Primary Examiner(s): NUZZOLILLO, MARIA
• Application Number:
  US08/559,120
• Time in Patent Office: 928 Days
• Field of Search: 429/192, 429/194, 429/218, 429/223, 429/224, 29/623.1, 29/623.2, 29/623.5
• US Class Current: 29/623.2
• CPC Class Codes: H01M 50/673 Containers for storing liquids; Delivery conduits therefor
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/4911 including sealing
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

A method for activating the anode, cathode, and polymeric matrix components of an electrochemical cell is provided. Subsequent to forming the electrochemical cell precursor a quantity of activation fluid comprising electrolyte solvent and an inorganic salt is added into the electrochemical cell precursor at a rate such that substantially all of the activation fluid is incorporated into the electrochemical cell precursor. The method produces electrochemical cells having consistent amounts of solvent and salts therein.

Claims

1. A method of activating an electrochemical cell precursor package which comprises the steps of:

(a) forming an electrochemical cell precursor package, said electrochemical cell precursor package including a moisture-impervious material having a sealable aperture therethrough, said material containing a porous structure comprising;

(i) an anode

(ii) a cathode; and

(iii) a polymeric matrix interposed between said anode and said cathode; and

(b) adding a quantity of activation fluid through said sealable aperture of the electrochemical cell precursor package at a rate such that substantially all of the activation fluid is incorporated into the porous structure.

2. The method of claim 1 wherein the activation fluid is added in a step-wise fashion such that measured quantities of said activation fluid is added until the electrochemical cell precursor is filled.

3. The method of claim 1 wherein the activation fluid is added in continuously diminishing volume into the electrochemical cell precursor package.

4. The method of claim 1 wherein adding the activation fluid comprises the steps of:

(i) introducing a part of the activation fluid into the electrochemical cell precursor package;

(ii) allowing the activation fluid to permeate into the porous structure of the electrochemical cell package;

(iii) adding an additional quantity of activation fluid into the electrochemical cell precursor package; and

(iv) repeating steps (ii) and (iii) until the porous structure is saturated.

5. The method of claim 1 wherein the activation fluid comprises an electrolyte solvent and inorganic salt.

13. The method of claim 1 further comprising the step of:

(c) sealing said aperture of said package to enclose the porous structure and the substantially absorbed activation fluid within the package.

6. A method of preparing an electrochemical cell, said method comprising the steps of:

forming an anode composition comprising a carbon material, a first polymer, and a first plasticizer;

forming a cathode composition comprising a cathode active material, a second polymer, and a second plasticizer;

forming a polymeric matrix comprising a third polymer and a third plasticizer;

removing said first, second, and third plasticizers to form a porous structure having an anode, a cathode, and a polymeric matrix interposed therebetween;

placing the porous structure into a package having a sealable aperture therethrough; and

adding a quantity of activation fluid through the aperture at a rate such that substantially all of the activation fluid is incorporated into the porous structure prior to sealing of the aperture.

7. The method of claim 6 wherein the activation fluid is added in a step-wise fashion such that measured quantities of said activation fluid is added until the electrochemical cell precursor is filled.

8. The method of claim 6 wherein the activation fluid is added continuously into the electrochemical cell precursor.

9. The method of claim 6 wherein adding the activation fluid comprises the steps of:

(i) introducing activation fluid into the package;

(ii) allowing the activation fluid to permeate into the porous structure;

(iii) adding an additional quantity of activation fluid into the package; and

(iv) continuing steps (ii) and (iii) until the porous structure is saturated.

10. The method of claim 6 wherein the first, second, and third plasticizers comprise dibutyl phthalate.

11. The method of claim 6 wherein the cathode active material is selected from the group consisting of lithiated manganese oxides, lithiated cobalt oxide, lithiated nickel oxides, vanadium oxides and mixture thereof.

12. The method of claim 6 wherein said first, second, and third polymers comprise polyvinylidene difluoride.

14. The method of claim 6 wherein the activation fluid comprises an electrolyte solvent and an inorganic salt.

15. The method of claim 6 further comprising the step of:

sealing said aperture of said package to enclose the porous structure and the activation fluid within the package.

16. A method of preparing an electrochemical cell, said method comprising the steps of:

(a) placing into a moisture-impermeable package a porous structure including;

(i) an anode;

(ii) a cathode;

(iii) a polymeric matrix interposed between said anode and said cathode;

(b) introducing activation fluid into the package at a rate such that substantially all of the activation fluid is incorporated into the porous structure prior to sealing of the package; and

(c) sealing the package.

17. The method of claim 16 wherein the activation fluid is added in a step-wise fashion such that measured quantities of said activation fluid is added until the porous structure is saturated.

18. The method of claim 16 wherein the activation fluid is added in continuously diminishing volume until the porous structure is saturated.

19. The method of claim 16 wherein the step of introducing activation fluid further comprises the steps of:

(i) introducing a part of the activation fluid into the package;

(ii) allowing the activation fluid to permeate into the porous structure within the package;

(iii) adding an additional quantity of activation fluid to the package; and

(iv) repeating steps (ii) and (iii) until the porous structure is saturated.

20. The method of claim 16 wherein the activation fluid comprises an electrolyte solvent and an inorganic salt.