CN-122029442-A - Method and device for diagnosing a battery

Abstract

The method for diagnosing a battery according to one aspect of the present disclosure includes a voltage determining step of determining an OCV (open circuit voltage) of the battery, a capacity selecting step of selecting a positive electrode capacity corresponding to the OCV from a positive electrode curve representing a correspondence between the positive electrode capacity and the positive electrode voltage of the battery and selecting a negative electrode capacity corresponding to the OCV from a negative electrode curve representing a correspondence between the negative electrode capacity and the negative electrode voltage of the battery, a depth calculating step of calculating a positive electrode depth, which is a ratio of the selected positive electrode capacity to the positive electrode total capacity of the battery, and a negative electrode depth, which is a ratio of the selected negative electrode capacity to the negative electrode total capacity of the battery, and a diagnosing step of diagnosing a state of the battery based on at least one of the positive electrode depth and the negative electrode depth.

Inventors

• Pu Xuanzhu
• Cui Chunzhu

Assignees

• 株式会社LG新能源

Dates

Publication Date

20260512

Application Date

20250225

Priority Date

20240325

Claims (15)

1. 1. A method for diagnosing a battery, comprising: a voltage determining step of determining an open circuit voltage OCV of the battery; A capacity selection step of selecting a positive electrode capacity corresponding to the OCV from a positive electrode curve representing a correspondence between a positive electrode capacity and a positive electrode voltage of the battery, and selecting a negative electrode capacity corresponding to the OCV from a negative electrode curve representing a correspondence between a negative electrode capacity and a negative electrode voltage of the battery; A depth calculation step of calculating a positive electrode depth, which is a ratio of the selected positive electrode capacity to the total positive electrode capacity of the battery, and a negative electrode depth, which is a ratio of the selected negative electrode capacity to the total negative electrode capacity of the battery, and And a diagnosis step of diagnosing a state of the battery based on at least one of the positive electrode depth and the negative electrode depth.
2. 2. The method for diagnosing a battery according to claim 1, Wherein the voltage determining step includes a step of determining a first OCV that is an OCV of the battery at the end of charge and a second OCV that is an OCV of the battery at the end of discharge, Wherein the capacity selecting step includes a step of selecting a positive electrode charge capacity, which is a positive electrode capacity corresponding to the first OCV, and a positive electrode discharge capacity, which is a positive electrode capacity corresponding to the second OCV, in the positive electrode curve, and Wherein the depth calculating step includes a step of calculating, as the positive electrode depth, at least one of a positive electrode charge depth, which is a ratio of the positive electrode charge capacity to the positive electrode total capacity, and a positive electrode discharge depth, which is a ratio of the positive electrode discharge capacity to the positive electrode total capacity.
3. 3. The method for diagnosing a battery according to claim 2, Wherein the diagnosing step includes a step of diagnosing whether the positive electrode of the battery is degraded based on at least one of the positive electrode charge depth and the positive electrode discharge depth.
4. 4. The method for diagnosing a battery according to claim 1, Wherein the voltage determining step includes a step of determining a first OCV that is an OCV of the battery at the end of charge and a second OCV that is an OCV of the battery at the end of discharge, Wherein the capacity selecting step includes a step of selecting a negative electrode charge capacity, which is a negative electrode capacity corresponding to the first OCV, and a negative electrode discharge capacity, which is a negative electrode capacity corresponding to the second OCV, in the negative electrode curve, and Wherein the depth calculating step includes a step of calculating, as the negative electrode depth, at least one of a negative electrode charge depth, which is a ratio of the negative electrode charge capacity to the negative electrode total capacity, and a negative electrode discharge depth, which is a ratio of the negative electrode discharge capacity to the negative electrode total capacity.
5. 5. The method for diagnosing a battery according to claim 4, Wherein the diagnosing step includes a step of diagnosing whether the negative electrode of the battery is degraded based on at least one of the negative electrode charge depth and the negative electrode discharge depth.
6. 6. The method for diagnosing a battery according to claim 1, Wherein the capacity selection step includes: Obtaining a battery curve representing a correspondence between a voltage and a capacity of the battery; adjusting a predetermined reference positive electrode curve and a reference negative electrode curve to correspond to the battery curve to determine the positive electrode curve and the negative electrode curve, and A positive electrode capacity corresponding to the OCV is selected in the positive electrode curve, and a negative electrode capacity corresponding to the OCV is selected in the negative electrode curve.
7. 7. The method for diagnosing a battery according to claim 1, Wherein the diagnosing step comprises: diagnosing whether the positive electrode of the battery is deteriorated based on the positive electrode depth, and Diagnosing whether a negative electrode of the battery is deteriorated based on the negative electrode depth.
8. 8. The method for diagnosing a battery according to claim 1, Wherein the diagnosing step includes the step of diagnosing the state of the battery as a degraded state when the positive electrode depth is less than or equal to a predetermined first reference value, when the negative electrode depth is less than or equal to a predetermined second reference value, or when the positive electrode depth is less than or equal to the first reference value and the negative electrode depth is less than or equal to the second reference value.
9. 9. The method for diagnosing a battery according to claim 1, further comprising: The use condition of the battery is controlled when the state of the battery is diagnosed as a deteriorated state.
10. 10. An apparatus for diagnosing a battery, comprising: a voltage determination unit configured to determine an OCV of the battery; A selection unit configured to select a positive electrode capacity corresponding to the OCV from a positive electrode curve representing a correspondence between a positive electrode capacity and a positive electrode voltage of the battery, and to select a negative electrode capacity corresponding to the OCV from a negative electrode curve representing a correspondence between a negative electrode capacity and a negative electrode voltage of the battery; a calculation unit configured to calculate a positive electrode depth, which is a ratio of the selected positive electrode capacity to a positive electrode total capacity of the battery, and a negative electrode depth, which is a ratio of the selected negative electrode capacity to the negative electrode total capacity of the battery, and And a diagnosis unit configured to diagnose a state of the battery based on at least one of the positive electrode depth and the negative electrode depth.
11. 11. The apparatus for diagnosing a battery according to claim 10, Wherein the voltage determination unit is configured to determine a first OCV that is an OCV of the battery at the end of charging and a second OCV that is an OCV of the battery at the end of discharging, Wherein the selection unit is configured to select a positive charge capacity and a positive discharge capacity in the positive curve, the positive charge capacity being a positive capacity corresponding to the first OCV, the positive discharge capacity being a positive capacity corresponding to the second OCV, and Wherein the calculation unit is configured to calculate, as the positive electrode depth, at least one of a positive electrode charge depth, which is a ratio of the positive electrode charge capacity to the positive electrode total capacity, and a positive electrode discharge depth, which is a ratio of the positive electrode discharge capacity to the positive electrode total capacity.
12. 12. The apparatus for diagnosing a battery according to claim 10, Wherein the voltage determination unit is configured to determine a first OCV that is an OCV of the battery at the end of charging and a second OCV that is an OCV of the battery at the end of discharging, Wherein the selection unit is configured to select a negative charge capacity and a negative discharge capacity in the negative curve, the negative charge capacity being a negative capacity corresponding to the first OCV, the negative discharge capacity being a negative capacity corresponding to the second OCV, and Wherein the calculation unit is configured to calculate, as the anode depth, at least one of an anode charge depth, which is a ratio of the anode charge capacity to the anode total capacity, and an anode discharge depth, which is a ratio of the anode discharge capacity to the anode total capacity.
13. 13. The apparatus for diagnosing a battery according to claim 10, Wherein the diagnosis unit is configured to diagnose whether a positive electrode of the battery is deteriorated based on the positive electrode depth, and to diagnose whether a negative electrode of the battery is deteriorated based on the negative electrode depth.
14. 14. A battery pack comprising the apparatus for diagnosing a battery according to any one of claims 10 to 13.
15. 15. A vehicle comprising the apparatus for diagnosing a battery according to any one of claims 10 to 13.

Description

Method and device for diagnosing a battery Technical Field The present application is based on and claims priority of korean patent application No. 10-2024-0040392 filed on 3/25 of 2024 to korean intellectual property office, the disclosure of which is incorporated herein by reference in its entirety. The present disclosure relates to a technique for diagnosing a state of a battery, and more particularly, to a method and apparatus for diagnosing a battery for effectively diagnosing a deteriorated state of a battery subjected to repeated charge and discharge. Background As the demand for portable electronic products such as notebook computers, video cameras, and mobile phones using electric power as an electric power source rapidly increases, and as mobile robots, electric bicycles, electric carts, electric vehicles, and ESS (energy storage systems) become more widely commercialized, research into high-performance batteries capable of repeated charge and discharge is actively being conducted. Currently available batteries include lithium batteries using lithium ions, such as lithium ion batteries or lithium ion polymer batteries, as well as nickel cadmium batteries, nickel hydrogen batteries, and nickel zinc batteries. Among them, lithium batteries have advantages of relatively long life, very low self-discharge rate, and high energy density because they have little memory effect compared to batteries using nickel, and thus their application range is gradually expanding. As charge and discharge cycles are repeated, the positive and negative electrodes of these batteries gradually deteriorate or age, and the batteries no longer maintain performance at BOL (beginning of life). Therefore, in order to accurately predict the available time, remaining life, and replacement time of the battery, an accurate diagnosis of the state of the battery is required. However, since the related art simply diagnoses the battery through SOH (state of health) of the entire battery, there is a problem in that the state of the battery cannot be diagnosed for each electrode. Disclosure of Invention Technical problem The present disclosure is designed to solve the problems of the related art, and therefore, it is an object of the present disclosure to provide a method and apparatus for diagnosing a battery, which can simply and accurately diagnose the state of the battery by distinguishing the state from electrode to electrode by quantifying the depth of each electrode and the area of use of each electrode by using curves representing the OCV and electrical characteristics of the battery. The technical problems the present disclosure seeks to solve are not limited to the above problems, and other problems not mentioned above will be clearly understood by those skilled in the art from the following description of the present invention. Technical proposal The method for diagnosing a battery according to one aspect of the present disclosure includes a voltage determining step of determining an OCV (open circuit voltage) of the battery, a capacity selecting step of selecting a positive electrode capacity corresponding to the OCV from a positive electrode curve representing a correspondence between the positive electrode capacity and the positive electrode voltage of the battery and selecting a negative electrode capacity corresponding to the OCV from a negative electrode curve representing a correspondence between the negative electrode capacity and the negative electrode voltage of the battery, a depth calculating step of calculating a positive electrode depth, which is a ratio of the selected positive electrode capacity to the positive electrode total capacity of the battery, and a negative electrode depth, which is a ratio of the selected negative electrode capacity to the negative electrode total capacity of the battery, and a diagnosing step of diagnosing a state of the battery based on at least one of the positive electrode depth and the negative electrode depth. In an embodiment, the voltage determining step may include a step of determining a first OCV that is an OCV of the battery at the end of charging and a second OCV that is an OCV of the battery at the end of discharging, the capacity selecting step may include a step of selecting a positive charge capacity and a positive discharge capacity in a positive curve, the positive charge capacity being a positive capacity corresponding to the first OCV, the positive discharge capacity being a positive capacity corresponding to the second OCV, and the depth calculating step may include a step of calculating at least one of a positive charge depth and a positive discharge depth as a positive depth, the positive charge depth being a ratio of the positive charge capacity to the positive total capacity, and the positive discharge depth being a ratio of the positive discharge capacity to the positive total capacity. In this case, the diagnosing step may include a step of diagnosing wheth