EP-4741849-A1 - BATTERY DIAGNOSIS APPARATUS AND BATTERY DIAGNOSIS METHOD

EP4741849A1EP 4741849 A1EP4741849 A1EP 4741849A1EP-4741849-A1

Abstract

There are provided a battery diagnosis apparatus and a battery diagnosis method. The battery diagnosis apparatus includes a sensing unit configured to measure a voltage of a battery cell, and a control circuit configured to determine an amount of voltage drop of the battery cell for each rest period based on a voltage measurement signal collected from the sensing unit at least twice every rest period. The control circuit is configured to generate self-discharge history data indicating a change in the amount of voltage drop over the plurality of rest periods. The control circuit is configured to diagnose a self-discharge state of the battery cell based on the self-discharge history data.

Inventors

YOO, IN-SUN
BAE, YOON-JUNG

Assignees

LG Energy Solution, Ltd.

Dates

Publication Date: 20260513
Application Date: 20250102

Claims (14)

A battery diagnosis apparatus comprising: a sensing unit configured to measure a voltage of a battery cell; and a control circuit configured to determine an amount of voltage drop of the battery cell for each rest period based on a voltage measurement signal collected from the sensing unit at least twice every rest period, wherein the control circuit is configured to: generate self-discharge history data indicating a change in the amount of voltage drop over the plurality of rest periods, and diagnose a self-discharge state of the battery cell based on the self-discharge history data.
The battery diagnosis apparatus according to claim 1, wherein the control circuit is configured to: determine a first risk level arising from an increasing trend of the amount of voltage drop when the increasing trend is identified from the self-discharge history data.
The battery diagnosis apparatus according to claim 2, wherein the control circuit is configured to: determine the first risk level according to an intensity of the increasing trend, and generate alarm information for warning the first risk level.
The battery diagnosis apparatus according to claim 1, wherein the control circuit is configured to: determine a second risk level arising from a decreasing trend of the amount of voltage drop when the decreasing trend is identified from the self-discharge history data.
The battery diagnosis apparatus according to claim 4, wherein the control circuit is configured to: determine the second risk level according to an intensity of the decreasing trend, and generate alarm information for warning the second risk level.
The battery diagnosis apparatus according to claim 1, wherein the control circuit is configured to: perform a protection operation for the battery cell according to a result of diagnosing the self-discharge state.
The battery diagnosis apparatus according to claim 6, wherein the protection operation includes at least one of: a first operation of limiting an allowable charging/discharging condition including at least one of a temperature range, a state of charge (SOC) range, a voltage range, a maximum charge current or a maximum discharge current for the battery cell; a second operation of determining a recommended timing of a next rest period to be allocated to the battery cell; or a third operation of outputting a diagnostic message indicating the result of the diagnosis.
A battery pack comprising the battery diagnosis apparatus according to any one of claims 1 to 7.
A battery system comprising the battery diagnosis apparatus according to any one of claims 1 to 7.
A battery diagnosis method comprising: determining an amount of voltage drop of a battery cell for each rest period based on a voltage measurement signal collected at least twice every rest period; generating self-discharge history data indicating a change in the amount of voltage drop over the plurality of rest periods; and diagnosing a self-discharge state of the battery cell based on the self-discharge history data.
The battery diagnosis method according to claim 10, wherein the diagnosing of the self-discharge state of the battery cell comprises: determining a first risk level arising from an increasing trend of the amount of voltage drop when the increasing trend is identified from the self-discharge history data.
The battery diagnosis method according to claim 10, wherein the diagnosing of the self-discharge state of the battery cell comprises: determining a second risk level arising from a decreasing trend of the amount of voltage drop when the decreasing trend is identified from the self-discharge history data.
The battery diagnosis method according to claim 10, further comprising: performing a protection operation for the battery cell according to a result of diagnosing the self-discharge state.
The battery diagnosis method according to claim 13, wherein the protection operation includes at least one of: a first operation of limiting an allowable charging/discharging condition including at least one of a temperature range, a state of charge (SOC) range, a voltage range, a maximum charge current or a maximum discharge current for the battery cell; a second operation of determining a recommended timing of a next rest period to be allocated to the battery cell; or a third operation of outputting a diagnostic message indicating the result of the diagnosis.

Description

TECHNICAL FIELD The present disclosure relates to self-discharge diagnosis in batteries. This application is based on and claims priority to Korean Patent Application No. 10-2024-0011568 filed on January 25, 2024 in the Republic of Korea, the disclosure of which is incorporated herein by reference. BACKGROUND Recently, there has been a rapid increase in the demand for portable electronic products such as laptop computers, video cameras and mobile phones, and with the extensive development of electric vehicles, accumulators for energy storage, robots and satellites, many studies are being made on high performance batteries that can be repeatedly charged and discharged. Currently, commercially available batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium batteries and the like, and among them, lithium batteries have little or no memory effect, and thus they are gaining more attention than nickel-based batteries for their advantages that recharging can be done whenever it is convenient, the self-discharge rate is very low and the energy density is high. A battery system that requires high voltage and/or large capacity such as an electric vehicle generally includes a plurality of batteries connected either in series or in parallel or both. In the battery system, a failure in any battery may adversely affect the performance and safety of the entire battery system. Accordingly, in the management of the battery system, it is important to properly detect a failure in the individual batteries. Among many different types of battery failures, a self-discharge failure relies on a self-discharge factor of the battery. Here, the self-discharge factor may include the amount and speed of voltage drop or a combination thereof. The self-discharge failure in the battery is generally determined based on voltage values of the battery measured two or more times during rest. However, failure determination based on the amount of voltage drop in a single rest period results in low accuracy. For example, when there is a temporary error or external noise in the process of measuring the voltage, inaccurate voltage values may be acquired, and the diagnosis result of self-discharge failure based on the voltage values has low reliability. DISCLOSURE Technical Problem The present disclosure is designed to solve the above-described problems, and therefore the present disclosure is directed to providing an apparatus and method for diagnosing a self-discharge state of a battery cell by analyzing a change in an amount of voltage drop of the battery cell based on voltage of the battery cell measured over a plurality of rest periods sequentially allocated by periodically or aperiodically stopping the charge/discharge of the battery cell. These and other objectives and advantages of the present disclosure may be understood from the following description and will become apparent from the embodiments of the present disclosure. Also, it will be easily understood that the objectives and advantages of the present disclosure may be realized by the means set forth in the appended claims and a combination thereof. Technical Solution A battery diagnosis apparatus according to an aspect of the present disclosure includes a sensing unit configured to measure a voltage of a battery cell, and a control circuit configured to determine an amount of voltage drop of the battery cell for each rest period based on a voltage measurement signal collected from the sensing unit at least twice every rest period. The control circuit is configured to generate self-discharge history data indicating a change in the amount of voltage drop over the plurality of rest periods. The control circuit is configured to diagnose a self-discharge state of the battery cell based on the self-discharge history data. The control circuit may be configured to determine a first risk level arising from an increasing trend of the amount of voltage drop when the increasing trend is identified from the self-discharge history data. The control circuit may be configured to determine the first risk level according to an intensity of the increasing trend. The control circuit may be configured to generate alarm information for warning the first risk level. The control circuit may be configured to determine a second risk level arising from a decreasing trend of the amount of voltage drop when the decreasing trend is identified from the self-discharge history data. The control circuit may be configured to determine the second risk level according to an intensity of the decreasing trend. The control circuit may be configured to generate alarm information for warning the second risk level. The control circuit may be configured to perform a protection operation for the battery cell according to a result of diagnosing the self-discharge state. The protection operation may include at least one of a first operation of limiting an allowable charging/dischargin