# US 2014/0197797 A1 · Electrochemical device

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- Number: US 2014/0197797 A1
- Document ID: US20140197797A1
- Status: Published application
- Kind: A1
- Application number: 14/153,510
- Filed: 2014-01-13
- Published: 2014-07-17
- Earliest claimed: 2013-01-14
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Shunpei YAMAZAKI
- Web page: https://patentgrep.com/patent/US20140197797A1

## CPC

- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00)
- H02J 7/04: Regulation of charging current or voltage
- H02J 7/92: with prioritisation of loads or sources
- H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)}
- H02J 7/927: {with introduction of pulses during the charging process}
- Y02E 60/10: Energy storage using batteries
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

To prevent deterioration of a battery or reduce the degree of deterioration of a battery and to maximize charge and discharge performance of the battery and maintain charge and discharge performance of the battery for a long time. A reaction product formed on an electrode surface causes various malfunctions and deterioration of a battery typified by a lithium-ion secondary battery. The present inventors have found a breakthrough technological idea that a reaction product is prevented from being deposited on an electrode in charging or discharging or a formed reaction product is dissolved by application of an electrical stimulus to an electrochemical device that operates utilizing an electrochemical reaction, typified by a lithium-ion secondary battery. Specifically, the reaction product is dissolved by supplying a signal (inversion pulse current) with which a current flows in the reverse direction of a current with which a reaction product is formed.

## Claims

### Claim 1

An electrochemical device comprising:
a first electrode that includes a first layer including a first active material;
a second electrode that includes a second layer including a second active material; and
an electrolytic solution between the first electrode and the second electrode,
wherein a reaction product is not substantially deposited on a surface of the first electrode or the second electrode.

### Claim 2 (depends on 1)

The electrochemical device according to claim 1,
wherein the first active material includes a metal element, and
wherein the metal element is not substantially deposited on the surface of the second electrode.

### Claim 3 (depends on 1)

The electrochemical device according to claim 1,
wherein the first active material includes a metal element that is released as a positive ion in charging, and
wherein the metal element is not substantially deposited on the surface of the second electrode.

### Claim 4

A method for charging and discharging an electrochemical device, the electrochemical device comprising:
a first electrode that includes a first layer including a first active material;
a second electrode that includes a second layer including a second active material; and
an electrolytic solution between the first electrode and the second electrode,
the method comprising the steps of:
supplying a first current between the first electrode and the second electrode in a first direction; and
supplying a second current between the first electrode and the second electrode in a reverse direction of the first direction,
wherein the first current and the second current flow alternately and repeatedly, and
wherein one period in which the second current flows is shorter than one period in which the first current flows.

### Claim 5 (depends on 4)

The method for charging and discharging an electrochemical device, according to claim 4,
wherein the one period in which the second current flows is longer than or equal to one hundredth of the one period in which the first current flows and shorter than or equal to one third of the one period in which the first current flows.

### Claim 6 (depends on 4)

The method for charging and discharging an electrochemical device, according to claim 4,
wherein the one period in which the second current flows is longer than or equal to 0.1 seconds and shorter than or equal to 3 minutes.

### Claim 7 (depends on 4)

The method for charging and discharging an electrochemical device, according to claim 4,
wherein the one period in which the second current flows is longer than or equal to 3 seconds and shorter than or equal to 30 seconds.