# US 12,002,934 B2 · Method and device for determining state of rechargeable battery

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- Number: US 12,002,934 B2
- Document ID: US12002934B2
- Status: Granted
- Kind: B2
- Application number: 17/239,353
- Filed: 2021-04-23
- Published: 2021-10-28
- Granted: 2024-06-04
- Earliest claimed: 2020-04-28
- Assignees: Primearth Ev Energy Co., Ltd.
- Applicants: Primearth Ev Energy Co., Ltd.
- Inventors: Tamotsu Fukuma; Hitoshi Suzuki; Daisuke Koba
- Web page: https://patentgrep.com/patent/US12002934B2

## CPC

- G01R 31/382: Arrangements for monitoring battery or accumulator variables, e.g. SoC
- H01M 10/484: {for measuring electrolyte level, electrolyte density or electrolyte conductivity}
- B60L 58/12: responding to state of charge [SoC]
- G01R 31/3842: combining voltage and current measurements
- G01R 31/389: Measuring internal impedance, internal conductance or related variables
- G01R 31/52: Testing for short-circuits, leakage current or ground faults
- H01M 50/569: Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals (battery terminal connectors with integrated measuring arrangements G01R31/364)
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- Y02E 60/10: Energy storage using batteries
- Y02T 10/70: Energy storage systems for electromobility, e.g. 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
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A rechargeable battery state determination method determines whether a rechargeable battery is in a micro-short-circuit-prone state, which is a state that is highly likely to form a micro-short circuit. The rechargeable battery state determination method includes measuring an electron transfer resistance of the rechargeable battery by applying a voltage or current having a predetermined or higher frequency to an electrode system of the rechargeable battery, determining whether an inter-electrode distance is satisfactory based on a comparison of the measured electron transfer resistance of the rechargeable battery with a predetermined lower limit threshold value, in which the determining whether an inter-electrode distance is satisfactory including determining that the inter-electrode distance is satisfactory when the measured electron transfer resistance of the rechargeable battery is greater than or equal to the lower limit threshold value, and determining that the rechargeable battery is a conforming piece when the inter-electrode distance is satisfactory.

## Claims

### Claim 1

A rechargeable battery state determination method that determines whether a rechargeable battery is in a micro-short-circuit-prone state, which is a state that is highly likely to form a micro-short circuit, the rechargeable battery state determination method, comprising:
measuring an electron transfer resistance of the rechargeable battery by applying a voltage or current having a predetermined or higher frequency to an electrode system of the rechargeable battery, wherein:
the electron transfer resistance of the rechargeable battery is correlated with an inter-electrode distance of the rechargeable battery and an amount of an electrolytic solution contained in a separator of the rechargeable battery; and
the measuring an electron transfer resistance of the rechargeable battery includes:
outputting a Nyquist plot by applying a voltage or current to the electrode system of the rechargeable battery as a frequency with very small amplitude is changed in a stepped manner to measure impedance spectrum of the rechargeable battery using an alternating current impedance method; and
obtaining a real value of a zero cross expressing the electron transfer resistance of the rechargeable battery from the outputted Nyquist plot;
determining whether the inter-electrode distance is satisfactory based on a comparison of the measured electron transfer resistance of the rechargeable battery with a predetermined lower limit threshold value, the determining whether an inter-electrode distance is satisfactory including determining that the inter-electrode distance is satisfactory when the measured electron transfer resistance of the rechargeable battery is greater than or equal to the lower limit threshold value;
determining whether the amount of the electrolytic solution contained in the separator is satisfactory based on a comparison of the measured electron transfer resistance of the rechargeable battery with a predetermined upper limit threshold value, the determining whether the amount of the electrolytic solution contained in the separator is satisfactory includes determining that the amount of the electrolytic solution contained in the separator is satisfactory when the measured electron transfer resistance of the rechargeable battery is less than the predetermined upper limit threshold value; and
determining that the rechargeable battery is a conforming piece when the inter-electrode distance and the amount of the electrolytic solution contained in the separator are satisfactory.

### Claim 2 (depends on 1)

The rechargeable battery state determination method according to claim 1, wherein the voltage or current applied to measure the electron transfer resistance of the rechargeable battery has a sine wave or a non-sinusoidal wave including a square wave, a triangle wave, and a sawtooth wave.

### Claim 3 (depends on 1)

The rechargeable battery state determination method according to claim 1, further comprising:
measuring a circuit voltage of the rechargeable battery; and
determining whether the micro-short circuit is formed base on a comparison of the measured circuit voltage of the rechargeable battery with a predetermined lower limit voltage threshold value, wherein
the determining whether the micro-short circuit is formed includes determining that the micro-short circuit is not formed when the measured circuit voltage of the rechargeable battery is greater than or equal to the predetermined lower limit voltage threshold value, and
the determining that the rechargeable battery is a conforming piece further includes determining that the rechargeable battery is a conforming piece when the micro-short circuit is not formed.

### Claim 4 (depends on 1)

The rechargeable battery state determination method according to claim 1, further comprising:
measuring a circuit voltage of the rechargeable battery; and
determining whether the micro-short circuit is formed base on a comparison of the measured circuit voltage of the rechargeable battery with a predetermined lower limit voltage threshold value, wherein
the determining whether the micro-short circuit is formed includes determining that the micro-short circuit is not formed when the measured circuit voltage of the rechargeable battery is greater than or equal to the predetermined lower limit voltage threshold value, and
the determining that the rechargeable battery is a conforming piece further includes determining that the rechargeable battery is a conforming piece when the micro-short circuit is not formed.