# US 4,743,520 A · Self-limiting electrochemical cell

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- Number: US 4,743,520 A
- Document ID: US4743520A
- Status: Granted
- Kind: A
- Application number: 06/932,044
- Filed: 1986-11-18
- Granted: 1988-05-10
- Earliest claimed: 1986-11-18
- Assignees: Power Conversion, Inc.
- Inventors: Martin G. Rosansky
- Web page: https://patentgrep.com/patent/US4743520A

## CPC

- H01M 6/14: Cells with non-aqueous electrolyte
- H01M 6/50: Methods or arrangements for servicing or maintenance, e.g. for maintaining operating temperature (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569)
- H01M 8/0289: Means for holding the electrolyte (solid polymer electrolytes H01M8/1018)
- H01M 6/10: with wound or folded electrodes
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A self-limiting electrochemical cell such as a lithium-sulfur dioxide cell having a non-porous, non-ion-permeable separator between the anode and cathode so as to control the passage of electrolyte and ion-transfer between the working electrodes thereby controlling the current drain based on the controlled amount of electrolyte. The invention provides a convenient method of controlling the drain rates of an electrochemical cell and permits utilization of conventional cells such as the lithium-sulfur dioxide, lithium-thionyl chloride, or lithium-sulfuryl chloride cells in applications not previously possible.

## Claims

### Claim 1

An electrochemical cell comprising a housing, an anode, a cathode, an electrolyte between and in contact with each of said anode and cathode, a microporous separator containing electrolyte adjacent to each of said anode and cathode, and a stationary barrier positioned between said microporous separators, said barrier being non-electrolyte and non-ion-permeable and having preselected openings substantially uniformly distributed in from about 60% to 1% of the total surface area to permit electrolyte passage and ion-transfer throught said openings in said barrier in controlled amounts, thereby providing said cell with self-limiting current characteristics.

### Claim 2 (depends on 1)

The elctrochemical cell of claim 1 wherein said microporous separators are composed of polypropylene.

### Claim 3 (depends on 2)

The electrochemical cell of claim 2 wherein said barrier is composed of polyethylene.

### Claim 4

A lithium-sulfur dioxide cell comprising a housing and within said housing a lithium anode, a cathode, an electrolyte between and in contact with each of said anode and cathode, each of said anode and cathode is adjacent and in contact with a microporous separator containing electrolyte, and a stationary barrier material positioned between said microporous separators, said barrier being non-electrolyte and non-ion-permeable and having preselected openings substantially uniformly distributed in form about 60% to 1% of the total surface area to permit electrolyte passage and ipn-transfer through said openings in said barrier in controlled amounts, thereby providing said cell with self-limiting current characteristics.

### Claim 5 (depends on 4)

The lithium-sulfur dioxide cell of claim 4 wherein the cathode is a carbon cathode.

### Claim 6 (depends on 5)

The lithium-sulfur dioxide cell of claim 5 wherein said microporous separators are composed of polypropylene.

### Claim 7 (depends on 6)

The lithium-sulfur dioxide cell of claim 6 wherein said barrier is composed of polyethylene.

### Claim 8 (depends on 5)

The lithium-sulfur dioxide cell of claim 5 wherein said anode, cathode, separator, and barrier are in rolled configuration within said housing.

### Claim 9

A lithium-oxyhalide cell which may optionally contain a second depolarizer comprising a housing and within said housing a lithium anode, a cathode, and electrolyte between and in contact with each of said anode and cathode, each of said anode and cathode is adjacent and in contact with a microporous separator containing electrolyte, and a stationary barrier material positioned between said microporous separators, said barrier being non-electrolyte and non-ion-permeable and having preselected openings substantially uniformly distributed in from about 60% to 1% of the total surface area to permit electrolyte passage and ion-transfer through said openings in said barrier in controlled amounts, thereby providing said cell with self-limiting current characteristics.

### Claim 10 (depends on 9)

The lithium-oxyhalide cell of claim 9 wherein the cathode is a carbon cathode.

### Claim 11 (depends on 9)

The lithium-oxyhalide cell of claim 9 wherein said microporous separators are composed of halocarbon polymers.

### Claim 12 (depends on 9)

The lithium-sulfur dioxide cell of claim 9 wherein said barrier is composed of a halocarbon polymer.

### Claim 13 (depends on 5)

The lithium-sulfur dioxide cell of claim 5 wherein said anode, cathode, separator, and barrier are in rolled configuration within said housing.