# US 2025/0085352 A1 · Apparatus and method for estimation of battery state-of-charge

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- Number: US 2025/0085352 A1
- Document ID: US20250085352A1
- Status: Published application
- Kind: A1
- Application number: 18/400,057
- Filed: 2023-12-29
- Published: 2025-03-13
- Earliest claimed: 2023-09-13
- Assignees: Samsung SDI Co., Ltd.
- Applicants: Samsung SDI Co., Ltd.
- Inventors: Sang Min HA
- Web page: https://patentgrep.com/patent/US20250085352A1

## CPC

- G01R 31/3842: combining voltage and current measurements
- 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)
- B60L 58/12: responding to state of charge [SoC]
- G01R 31/3648: {comprising digital calculation means, e.g. for performing an algorithm}
- G01R 31/367: Software therefor, e.g. for battery testing using modelling or look-up tables
- G01R 31/3835: involving only voltage measurements
- G01R 31/396: Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
- H01M 10/482: {for several batteries or cells simultaneously or sequentially}
- H02J 7/82: Control of state of charge [SOC]
- Y02E 60/10: Energy storage using batteries
- 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
- 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
- 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

A battery state-of-charge estimation apparatus include: a memory, and a processor connected to the memory. Upon charging/discharging of a battery rack including multiple battery cells, the processor calculates a maximum SOC of a maximum-voltage cell and a minimum SOC of a minimum-voltage cell and calculates a representative SOC of the battery rack based on the maximum SOC and the minimum SOC. A corresponding battery state-of-charge estimation method is also disclosed.

## Claims

### Claim 1

A battery state-of-charge estimation apparatus, comprising:
a memory; and
a processor connected to the memory,
wherein, upon charging/discharging a battery rack comprising multiple battery cells, the processor calculates a maximum state of charge (SOC) of a maximum-voltage cell and a minimum SOC of a minimum-voltage cell and calculates a representative SOC of the battery rack based on the maximum SOC and the minimum SOC.

### Claim 2 (depends on 1)

The battery state-of-charge estimation apparatus as claimed in claim 1, wherein, upon charging/discharging the battery rack, the processor calculates the maximum SOC based on a voltage and current of the maximum-voltage cell having a highest voltage among voltages of the multiple battery cells, and calculates the minimum SOC based on a voltage and current of the minimum-voltage cell having a lowest voltage among the voltages of the multiple battery cells.

### Claim 3 (depends on 1)

The battery state-of-charge estimation apparatus as claimed in claim 1, wherein the processor calculates a first weight of the maximum SOC and a second weight of the minimum SOC based on a battery operation range, an average SOC and a deviation SOC of the maximum SOC and the minimum SOC, and applies the first weight and the second weight to the maximum SOC and the minimum SOC, respectively, to calculate the representative SOC.

### Claim 4 (depends on 3)

The battery state-of-charge estimation apparatus as claimed in claim 3, wherein the processor applies the deviation SOC to a first SOC upper limit and a first SOC lower limit corresponding to the battery operation range to calculate a second SOC upper limit and a second SOC lower limit, and calculates the first weight of the maximum SOC and the second weight of the minimum SOC based on the second SOC upper limit, the second SOC lower limit, and the average SOC.

### Claim 5 (depends on 4)

The battery state-of-charge estimation apparatus as claimed in claim 4, wherein the processor subtracts a preset ratio of the deviation SOC from the first SOC upper limit to calculate the second SOC upper limit and adds the preset ratio of the deviation SOC to the first SOC lower limit to calculate the second SOC lower limit.

### Claim 6 (depends on 4)

The battery state-of-charge estimation apparatus as claimed in claim 4, wherein the processor calculates the second weight by dividing a value obtained through subtraction of the average SOC from the second SOC upper limit by a value obtained through subtraction of the second SOC lower limit from the second SOC upper limit, and calculates the first weight by subtracting the second weight from 1.

### Claim 7

A battery state-of-charge estimation method comprising, upon charging/discharging a battery rack comprising multiple battery cells:
receiving, by a processor, measurement data of each of the battery cells from a sensor;
calculating, by the processor, a maximum SOC of a maximum-voltage cell and a minimum SOC of a minimum-voltage cell based on the measurement data of each of the battery cells; and
calculating, by the processor, a representative SOC of the battery rack based on the maximum SOC and the minimum SOC.

### Claim 8 (depends on 7)

The battery state-of-charge estimation method as claimed in claim 7, wherein, in calculating the maximum SOC of the maximum-voltage cell and the minimum SOC of the minimum-voltage cell, the processor calculates the maximum SOC based on a voltage and current of the maximum-voltage cell having a highest voltage among voltages of the multiple battery cells, and the minimum SOC based on a voltage and current of the minimum-voltage cell having a lowest voltage among the voltages of the multiple battery cells.

### Claim 9 (depends on 7)

The battery state-of-charge estimation method as claimed in claim 7, wherein calculating a representative SOC of the battery rack includes:
calculating, by the processor, an average SOC and a deviation SOC of the maximum SOC and the minimum SOC;
applying, by the processor, the deviation SOC to a first SOC upper limit and a first SOC lower limit corresponding to a battery operating range to calculate a second SOC upper limit and a second SOC lower limit;
calculating, by the processor, a first weight of the maximum SOC and a second weight of the minimum SOC based on the second SOC upper limit, the second SOC lower limit, and the average SOC; and
applying, by the processor, the first weight and the second weight to the maximum SOC and the minimum SOC, respectively, to calculate the representative SOC of the battery rack.

### Claim 10 (depends on 9)

The battery state-of-charge estimation method as claimed in claim 9, wherein, in calculating the second SOC lower limit, the processor subtracts a preset ratio of the deviation SOC from the first SOC upper limit to calculate the second SOC upper limit and adds the preset ratio of the deviation SOC to the first SOC lower limit to calculate the second SOC lower limit.

### Claim 11 (depends on 9)

The battery state-of-charge estimation method as claimed in claim 9, wherein, in calculating the second weight, the processor divides a value obtained through subtraction of the average SOC from the second SOC upper limit by a value obtained through subtraction of the second SOC lower limit from the second SOC upper limit and calculates the first weight by subtracting the second weight from 1.