Lightweight battery electrode and method of making it

• US 5,197,993 A
• Filed: 07/11/1991
• Issued: 03/30/1993
• Est. Priority Date: 07/11/1991
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Ferrando, William A., Divecha, Amarnath P.
• Primary Examiner(s): Skapars, Anthony
• Application Number:
  US07/728,915
• Time in Patent Office: 628 Days
• Field of Search: 29/2, 29/623.5, 427/212, 427/229, 427/237, 427/250, 427/331, 264/56, 264/105, 264/126, 264/258, 429/235, 429/245
• US Class Current: 29/2
• CPC Class Codes: C22C 49/14 characterised by the fibres or filaments
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/16 from metal carbonyl compounds
• CPC Class Codes: H01M 4/80 Porous plates, e.g. sintered carriers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/10 Battery-grid making
• CPC Class Codes: Y10T 29/49115 including coating or impregnating
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]

Abstract

A process for producing a lightweight electrode grid by exposing a heated t of dense graphite fibers to Ni(CO)₄ gas wherein the Ni(CO)₄ decomposes upon contact with the graphite fibers depositing nickel metal coating on the graphic fibers. The nickel coated graphite fibers are then sintered to form the grid. Nickel or cadmium electrodes are made by attaching a current collector to the grid and impregnating the grid with the appropriate nickel or cadmium active material.

Claims

1. A process for producing a lightweight electrode grid comprising:

A. heating a mat of dense graphite fibers to a temperature at which Ni(CO)₄ decomposes;

B. exposing the heated mat of graphite fibers to Ni(CO)₄ gas which is at a temperature above the vaporization temperature of Ni(CO)₄ but below the decomposition temperature of Ni(CO)₄,

wherein the Ni(CO)₄ decomposes when it contacts the heated graphite fibers and deposits nickel metal on the graphite fiber surfaces;

C. removing the heated graphite fiber mat from the Ni(CO)₄ gas when the desired thickness of nickel metal coating has been produced on the graphite fiber mat; and

D. sintering the nickel coated graphite fiber mat in a reducing atmosphere under heat and pressure to compress the mat to a desired thickness and to fuse the nickel metal coated graphite fibers together.

2. The process of claim 1 wherein in the sinter process of step D the nickel coated graphite fiber mat is attached to a current collector.

3. The process of claim 1 wherein the mat of dense graphite fibers is heated in step A to a temperature of from 125°

C. to 600°

C.

4. The process of claim 3 wherein the mat of dense graphite fibers is heated in step A to a temperature of from 160°

C. to 500°

C.

5. The process of claim 4 wherein the mat of dense graphite fibers is heated in step A to a temperature of from 180°

C. to 350°

C.

6. The process of claim 1 wherein heating means are used in step B to maintain the temperature of the mat of graphite fibers.

7. The process of claim 1 wherein the carbon monoxide generated by the decomposition of Ni(CO)₄ in step B is taken and reacted with fine nickel metal powder to produce more Ni(CO)₄ gas for use in step B.

8. The process of claim 1 wherein the reducing atmosphere used in step D is pure hydrogen gas.

9. The process of claim 1 wherein the sintering temperature in step D is from about 775°

C. to about 975°

C.

10. The process of claim 9 wherein the sintering temperature in step D is from 800°

C. to 950°

C.

11. The process of claim 10 wherein the sintering temperature in step D is from 810°

C. to 900°

C.