# US 8,541,122 B2 · Lithium rechargeable cell with reference electrode for state of health monitoring > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,122 B2 - Document ID: US8541122B2 - Status: Granted - Kind: B2 - Application number: 13/448,999 - Filed: 2012-04-17 - Published: 2012-10-18 - Granted: 2013-09-24 - Earliest claimed: 2007-09-14 - Assignees: A123 Systems, Inc. - Applicants: Ricardo Fulop; Yet-Ming Chiang; Karen E. Thomas-Alyea; William H. Gardner - Inventors: Ricardo Fulop; Yet-Ming Chiang; Karen E. Thomas-Alyea; William H. Gardner - Web page: https://patentgrep.com/patent/US8541122B2 ## CPC - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - G01R 31/54: Testing for continuity - H01M 10/425: {Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00)} - H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00) - 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 50/55: on the same side of the cell - H01M 50/553: Terminals adapted for prismatic, pouch or rectangular cells - H01M 50/559: Terminals adapted for cells having curved cross-section, e.g. round, elliptic or button cells (H01M50/553 takes precedence) - H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries - H02J 7/52: for charge balancing, e.g. equalisation of charge between batteries - H02J 7/751: {concerning the insertion or the connection of the batteries} - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - H01M 50/562: characterised by the material - H01M 50/566: by welding, soldering or brazing - Y02E 60/10: Energy storage using batteries - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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 - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A battery management system includes one or more lithium ion cells in electrical connection, each said cell comprising: first and second working electrodes and one or more reference electrodes, each reference electrode electronically isolated from the working electrodes and having a separate tab or current collector exiting the cell and providing an additional terminal for electrical measurement; and a battery management system comprising a battery state-of-charge monitor, said monitor being operable for receiving information relating to the potential difference of the working electrodes and the potential of one or more of the working electrodes versus the reference electrode. ## Claims ### Claim 1 A battery, comprising: first and second working electrodes separated by at least one separator, the first working electrode in electrical connection with a first terminal, and the second working electrode in electrical connection with a second terminal; one or more reference electrodes; and a can housing the working electrodes and the one or more reference electrodes, wherein the can is electrically isolated from the first and second terminals and the one or more reference electrodes are integral to the can so that the can is electrically connected to the one or more reference electrodes to provide terminals for the one or more reference electrodes with the exterior of the can, and exposed metal surfaces of the can are coated with a nonporous electrically insulating coating. ### Claim 2 (depends on 1) The battery of claim 1, wherein the battery is a lithium ion battery and the working electrodes comprise electroactive materials capable lithium uptake and release. ### Claim 3 (depends on 1) The battery of claim 1, wherein the battery comprises a cylindrical cell of wound construction. ### Claim 4 (depends on 1) The battery of claim 1, wherein the battery comprises a prismatic cell of wound or stacked construction. ### Claim 5 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are comprised of an electroactive material capable of multiphase existence to provide a substantially constant voltage between about 1 V and about 4 V with respect to Li/Li+. ### Claim 6 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are capable of interface with a battery management system for the charging of the battery and for monitoring state of charge. ### Claim 7 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes have as little as about 0.001% and up to as much as about 20% of the coulombic capacity of the working electrodes. ### Claim 8 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are selected from the group consisting of lithium titanium oxide, lithium transition-metal phosphate, lithium manganese spinel, with or without substituent elements, and alloys of lithium with metals such as tin, aluminum, and antimony. ### Claim 9 (depends on 2) The battery of claim 2, wherein the battery is one of a plurality of batteries comprising a battery pack. ### Claim 10 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are positioned at a location in the battery most susceptible to lithium plating during charge. ### Claim 11 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are located between the working electrodes. ### Claim 12 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are substantially adjacent to the edge of the negative electrode, and prevented from contacting the negative electrode by a porous, electronically insulating layer. ### Claim 13 (depends on 2) The battery of claim 2, wherein the active material for the one or more reference electrodes is coated onto at least part of a wall of the can. ### Claim 14 (depends on 13) The lithium-ion battery of claim 13, wherein the can consists of a metal from the group comprising aluminum, copper, stainless steel, and titanium and the can provides both the reference electrode and the reference electrode terminal. ### Claim 15 (depends on 2) The battery of claim 2, wherein the first and second terminals are located in upper and lower cover plates, respectively. ### Claim 16 (depends on 15) The lithium-ion battery of claim 15, wherein the first and second terminals are electrically isolated from the can via gaskets. ### Claim 17 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are wrapped in a porous electronically isolating material that is electrochemically inert. ### Claim 18 (depends on 17) The lithium-ion battery of claim 17, where the porous electronically insulating material is wetted by the battery electrolyte. ### Claim 19 (depends on 2) The battery of claim 2, wherein the one or more reference electrodes are applied to the interior wall of the can.