# US 2025/0147115 A1 · Method for estimating the state of health of an electric or hybrid vehicle battery

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- Number: US 2025/0147115 A1
- Document ID: US20250147115A1
- Status: Published application
- Kind: A1
- Application number: 18/837,466
- Filed: 2023-02-03
- Published: 2025-05-08
- Earliest claimed: 2022-02-17
- Assignees: Ampere S.A.S.
- Applicants: Ampere S.A.S.
- Inventors: Mohamed ATI; Samuel CREGUT; Isabel JIMENEZ-GORDON; Jana KALAWOUN; Julien MALRIEU; Masato ORIGUCHI
- Web page: https://patentgrep.com/patent/US20250147115A1

## CPC

- G01R 31/392: Determining battery ageing or deterioration, e.g. state of health
- B60L 58/13: Maintaining the SoC within a determined range
- B60L 58/16: responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
- G01R 31/3835: involving only voltage measurements
- G01R 31/006: {on road vehicles, e.g. automobiles or trucks (testing of ignition installations peculiar to internal combustion engines F02P17/00)}
- G01R 31/374: with means for correcting the measurement for temperature or ageing
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES

## Abstract

A method for estimating the state of health of an electric or hybrid vehicle battery that can be carried out while the vehicle is running includes: (a) a full charge step; (b) a first relaxation step; (c) a step of discharging to a state of charge SOC≤SOCtarget carried out in k vehicle driving cycles, for each of which the capacity Qn discharged by the battery is determined; (d) a second relaxation step at the end of the cycle k; (e) a step of determining a state of charge SOCOCV as a function of the open circuit voltage; (f) a step of determining an initial discharge capacity Qi of the new battery from SOCOCV; and (g) a step of estimating the state of health SOH of the battery from the total capacity discharged by the battery during step (c) and from Qi.

## Claims

### Claim at position 1

1-10. (canceled)

### Claim 11

A method for estimating the state of health of a battery of an electric or hybrid vehicle, comprising:
(a) a step of charging the battery until the battery reaches a maximum state of charge SOCmax;
(b) a first relaxation step, during which the battery is not used for a first duration;
(c) a step of discharging the battery until the battery reaches a state of charge that is less than or equal to a non-zero target state of charge SOCtarget, with the discharging step being carried out in a number k of running cycles of the vehicle, with k being a non-zero integer, and, for each running cycle n where 1≤n≤k, the capacity Qn discharged by the battery is determined;
(d) a second relaxation step, at the end of the running cycle k, during which step the battery is not used for a second duration;
(e) a step of determining a state of charge SOCOCV of the battery as a function of the open-circuit voltage, with the battery not being used;
(f) a step of determining an initial discharge capacity Qi of the battery in a new state based on the state of charge determined in step (e) and on a previously established correlation for the battery in a new state and correlating the initial discharge capacity with the state of charge of the battery; and
(g) a step of estimating the state of health SOH of the battery based on the total capacity discharged by the battery during the discharging step (c) and on the initial discharge capacity determined in step (f).

### Claim 12 (depends on 11)

The estimation method as claimed in claim 11, wherein, during the estimating step (g), the state of health SOH of the battery is estimated using the following equation:
[
Math
⁢
1
]
S
⁢
O
⁢
H
=
∑
n
=
1
k
⁢
Q
n
Q
i
×
1
⁢
0
⁢
0
where Qn represents the capacity discharged by the battery during a running cycle n, with n being a non-zero integer ranging from 1 to k, and Qi represents the initial discharge capacity.

### Claim 13 (depends on 11)

The estimation method as claimed in claim 11, further comprising, between the first relaxation step (b) and the discharging step (c), a checking step involving checking that the state of charge of the battery in the relaxed state has reached the maximum state of charge.

### Claim 14 (depends on 11)

The estimation method as claimed in claim 11, wherein, during the discharging step (c), for each running cycle, the capacity discharged by the battery takes into account a charging capacity received by the battery.

### Claim 15 (depends on 11)

The estimation method as claimed in claim 11, wherein, during the discharging step (c), the capacity discharged by the battery (i) is determined by Coulomb counting the ampere-hours drawn from the battery, or (ii) by Coulomb counting the ampere-hours drawn from and supplied to the battery and by subtracting the ampere-hours supplied to the battery from the ampere-hours drawn from the battery.

### Claim 16 (depends on 11)

The estimation method as claimed in claim 11, wherein, for each running cycle n of the discharging step (c), a value of the state of charge SOCn of the battery (i) is estimated by measuring the voltage of the battery when running or (ii) by Coulomb counting, then the value of the state of charge SOCn is compared with the target state of charge value SOCtarget and step (c) is considered to be complete when SOCn is less than or equal to SOCtarget.

### Claim 17 (depends on 11)

The estimation method as claimed in claim 11, wherein the correlation used during step (f) has been set for a defined temperature range, and, during each running cycle of the discharging step (c), (i) the battery is maintained at a temperature within the defined temperature range, or (ii) a corrective factor is applied to the capacity Qn discharged by the battery as a function of the temperature of the battery.

### Claim 18 (depends on 11)

A non-transitory computer readable medium storing a program that, when executed by a computer, causes the computer to execute the estimation method as claimed in claim 11.

### Claim 19 (depends on 11)

A battery management system configured to estimate the state of charge of a battery by implementing the steps of the estimation method as claimed in claim 11.

### Claim 20 (depends on 19)

A motor vehicle equipped with a traction battery comprising the battery management system as claimed in claim 19.