# US 12,184,114 B2 · Battery system

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- Number: US 12,184,114 B2
- Document ID: US12184114B2
- Status: Granted
- Kind: B2
- Application number: 17/560,843
- Filed: 2021-12-23
- Published: 2022-07-07
- Granted: 2024-12-31
- Earliest claimed: 2021-01-07
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Takayuki Miyajima
- Web page: https://patentgrep.com/patent/US12184114B2

## CPC

- H02J 7/96: in response to battery voltage
- G01R 31/3835: involving only voltage measurements
- H01M 10/052: Li-accumulators
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/0562: Solid materials
- H01M 10/0585: of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
- 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 2010/4271: {Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing}
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- H01M 2300/0065: Solid electrolytes
- H01M 2300/0068: inorganic
- H02J 7/80: including monitoring or indicating arrangements
- Y02E 60/10: Energy storage using batteries
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- 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 battery system comprising a controller and a solid-state lithium secondary battery, wherein, the controller estimates an end part cathode potential Ve2 from a voltage relaxation amount ΔV2; the end part cathode potential Ve2 is a local potential of an end part of the cathode; and the voltage relaxation amount ΔV2 is generated by diffusion of, into the non-facing part of the anode, lithium transferred to the facing part of the anode from the cathode of the solid-state lithium secondary battery is a charged state, and wherein the controller controls execution and inexecution of charging of the solid-state lithium secondary battery so that the end part cathode potential Ve2 is equal to or less than a potential Vlimit at which a change in crystal structure of the cathode active material occurs.

## Claims

### Claim 1

A battery system comprising a controller and a solid-state lithium secondary battery comprising a cathode, an anode and a solid electrolyte layer disposed between the cathode and the anode,
wherein the cathode comprises a cathode layer;
wherein the cathode layer comprises a cathode active material;
wherein the anode comprises a facing part and a non-facing part; the facing part is a region facing the cathode; and the non-facing part is a region non-facing the cathode;
wherein the controller estimates an end part cathode potential Ve2 from a voltage relaxation amount ΔV2; the end part cathode potential Ve2 is a local potential of an end part of the cathode; and the voltage relaxation amount ΔV2 is generated by diffusion of, into the non-facing part of the anode, lithium transferred to the facing part of the anode from the cathode of the solid-state lithium secondary battery in a charged state; and
wherein the controller controls execution and inexecution of charging of the solid-state lithium secondary battery so that the end part cathode potential Ve2 is equal to or less than a potential Vlimit at which a change in crystal structure of the cathode active material occurs.

### Claim 2 (depends on 1)

The battery system according to claim 1,
wherein the controller detects a voltage V1 of the solid-state lithium secondary battery and calculates an end part cathode potential Ve1 from the voltage V1, which is a local potential of the end part of the cathode;
wherein the controller determines whether or not the voltage V1 is a voltage at which the end part cathode potential Ve1 is equal to or less than the potential Vlimit;
wherein, when the voltage V1 is determined to be the voltage at which the end part cathode potential Ve1 is equal to or less than the potential Vlimit, the controller sets the voltage at which the end part cathode potential Ve1 is equal to the potential Vlimit, to a first charging inhibition voltage, and the controller executes first charging by which the solid-state lithium secondary battery is charged until the first charging inhibition voltage is reached;
wherein, after the first charging, the controller suspends charging and discharging of the solid-state lithium secondary battery for a certain period of time;
wherein the controller measures the voltage relaxation amount ΔV2, estimates the end part cathode potential Ve2 from the voltage relaxation amount ΔV2, and corrects the end part cathode potential Ve1 to the end part cathode potential Ve2;
wherein the controller detects a voltage V2 of the solid-state lithium secondary battery and determines whether or not the voltage V2 is a voltage at which the end part cathode potential Ve2 is equal to or less than the potential Vlimit; and
wherein, when the voltage V2 is determined to be the voltage at which the end part cathode potential Ve2 is equal to or less than the potential Vlimit, the controller sets the voltage at which the end part cathode potential Ve2 is equal to the potential Vlimit, to a second charging inhibition voltage, and the controller executes second charging by which the solid-state lithium secondary battery is charged until the second charging inhibition voltage is reached.

### Claim 3 (depends on 2)

The battery system according to claim 2,
wherein the controller discharges the solid-state lithium secondary battery after the second charging;
wherein the controller detects a voltage V3 of the solid-state lithium secondary battery;
wherein the controller determines whether or not the voltage V3 is a voltage at which the end part cathode potential Ve2 is less than the potential Vlimit; and
wherein, when the voltage V3 is determined to be the voltage at which the end part cathode potential Ve2 is less than the potential Vlimit, the controller resets settings of the first and second charging inhibition voltages.