# US 2014/0191727 A1 · Metal-Air Accumulator with Air Electrode Protection Device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191727 A1 - Document ID: US20140191727A1 - Status: Published application - Kind: A1 - Application number: 14/117,527 - Filed: 2012-05-15 - Published: 2014-07-10 - Earliest claimed: 2011-05-19 - Assignees: Electricite de France - Inventors: Gwenaelle Toussaint; Philippe Stevens; Bernard Toussaint - Web page: https://patentgrep.com/patent/US20140191727A1 ## CPC - H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00) - H01M 10/425: {Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00)} - H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) - H01M 12/08: composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type - H01M 50/574: Devices or arrangements for the interruption of current - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - Y02E 60/10: Energy storage using batteries - 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 ## Abstract The present invention relates to a rechargeable accumulator comprising one or more metal-air cells, each cell comprising a first terminal (1) and a second terminal (2), a metallic negative electrode (3) for metal-air cell, connected to the first terminal (1), a first positive electrode (4) for releasing oxygen, a second positive electrode (5) which is a porous air electrode containing at least one oxygen reducing catalyst, an electrolyte, control means (6) suitable for continuously comparing the voltage measured between the terminal (2) and the terminal (1) with a setpoint value and for dispatching a switching signal to the switching means (7) when the measured voltage becomes smaller than the setpoint value, switching means (7) suitable for receiving a switching signal originating from the control means (6) and for connecting and disconnecting the air electrode (5) of the second terminal (2). The present invention also relates to a method using such an accumulator. ## Claims ### Claim 1 A rechargeable accumulator comprising one or more metal-air cells, each cell comprising a first terminal and a second terminal, a metal negative electrode for a metal-air cell, connected to the first terminal, a first positive oxygen-releasing electrode, a second positive electrode, which is a porous air electrode containing at least one oxygen reducing catalyst, and an electrolyte, a control adapted to continuously compare the measured voltage between the second terminal and the first terminal to a setpoint value and to send a switch signal to switching means when the measured voltage falls below the setpoint value, a commutator adapted to receive a switch signal originating from the control and to connect and disconnect the air electrode from the second terminal. ### Claim 2 (depends on 1) The accumulator of claim 1, wherein the negative electrode is a lithium electrode (Li/LiOH) or a zinc electrode (Zn/Zn(OH)42−). ### Claim 3 (depends on 1, 2) The accumulator of claim 1 or claim 2, wherein the first positive oxygen-releasing electrode is a silver electrode (Ag/AgO) or a nickel electrode (Ni/NiO or NiOH/NiOOH). ### Claim 4 (depends on 1) The accumulator of claim 1, wherein the air electrode comprises carbon particles and on at least one oxygen reducing catalyst. ### Claim 5 (depends on 1) The accumulator of claim 1, wherein the oxygen reducing catalyst in the air electrode is chosen from the group formed by manganese oxide and cobalt oxide. ### Claim 6 (depends on 1) The accumulator of claim 1, wherein the setpoint value is set to a value lower than the open circuit voltage of the cell in the charged state when only the air electrode is connected. ### Claim 7 (depends on 1) The accumulator of claim 1, wherein the control is an electromechanical relay driven by an operational amplifier. ### Claim 8 (depends on 1) The accumulator of claim 1, wherein the first positive electrode takes the form of a grid or of a perforated plate and lies between the negative electrode and the air electrode. ### Claim 9 A method for storing and releasing electrical energy using an accumulator as claimed in any one of the preceding claims, said method comprising the following successive steps: (a) a charging phase during which the negative electrode is connected to the first terminal, the first positive electrode is connected to the second terminal and the air electrode is disconnected, (b) a first discharging phase during which the negative electrode is connected to the first terminal, the first positive electrode is connected to the second terminal, the air electrode is disconnected, and the control continuously compares the measured voltage between the terminal and the first terminal to a setpoint value, (c) a first switching step during which the second positive electrode, which is the air electrode, is connected to the second terminal when the value of the voltage between the second terminal and the first terminal falls below the setpoint value, (d) a second discharging phase during which the negative electrode is connected to the first terminal, and the air electrode is connected to the second terminal, and (e) a second switching step during which the air electrode is disconnected from the second terminal. ### Claim 10 (depends on 9) The method of claim 9, wherein the first switching step, the commutator disconnects the first positive electrode from the second terminal. ### Claim 11 (depends on 9) The method of claim 9, wherein the first switching step, the commutator does not disconnect the first positive electrode from the second terminal.