EP-4737929-A2 - BATTERY DIAGNOSIS APPARATUS, BATTERY DIAGNOSIS METHOD, BATTERY PACK, AND VEHICLE

EP4737929A2EP 4737929 A2EP4737929 A2EP 4737929A2EP-4737929-A2

Abstract

Disclosed is a battery diagnosis apparatus, which includes a voltage sensing circuit configured to generate a voltage signal indicating a cell voltage of a battery cell; a storage medium configured to store time series data for the cell voltage; and a control circuit operably coupled with the voltage sensing circuit and the storage medium. The control circuit is configured to (i) receive the voltage signal and record the time series data for the cell voltage in the storage medium, (ii) select k th , k+1 th , and k+2 th measured cell voltage set from the time series data as diagnostic data (k is an index indicating a measurement order of the cell voltage and is a natural number of 1 or more to which a plurality of values is assigned), (iii) determine a first voltage difference between the k th cell voltage and the k+1 th cell voltage and a second voltage difference between the k+1 th cell voltage and the k+2 th cell voltage, and (iv) diagnose the battery cell as exhibiting a voltage abnormality, when, for a plurality of cell voltage sets, a count number of cell voltage sets for which a normal diagnosis condition where the p square of the first voltage difference (p is a natural number of 1 or more) is greater than the p square of the second voltage difference is not established is greater than or equal to a criterion value.

Inventors

YEOM, In-Cheol

Assignees

LG Energy Solution, Ltd.

Dates

Publication Date: 20260506
Application Date: 20230915

Claims (15)

A battery diagnosis apparatus (200), comprising: a voltage sensing circuit (210) configured to measure a cell voltage of a battery cell (BC 1 , BC N ); a storage medium (221) configured to store time series data for the cell voltage; and a control circuit (220) operably coupled with the voltage sensing circuit and the storage medium, wherein the control circuit is configured to: record the time series data for the cell voltage in the storage medium, characterised in that the control circuit is further configured to: determine, based on the time series data, a first voltage difference between a cell voltage measured at a first time and a cell voltage measured at a second time and a second voltage difference between the cell voltage measured at the second time and a cell voltage measured at a third time, and diagnose the battery cell based on the first voltage difference and the second voltage difference.
The battery diagnosis apparatus according to claim 1, wherein the control circuit is configured to diagnose the battery cell based on the p square of the first voltage difference (p is a natural number of 1 or more) and the p square of the second voltage difference.
The battery diagnosis apparatus according to claim 2, wherein the control circuit is configured to diagnose the battery cell based on whether a normal diagnosis condition where the p square of the first voltage difference is greater than the p square of the second voltage difference is established.
The battery diagnosis apparatus according to claim 2, wherein the control circuit is configured to diagnose the battery cell based on a count number for which a normal diagnosis condition where the p square of the first voltage difference is greater than the p square of the second voltage difference is not established.
The battery diagnosis apparatus according to claim 2, wherein p is 1 or greater.
The battery diagnosis apparatus according to claim 2, wherein the criterion value is 1 or greater.
The battery diagnosis apparatus according to claim 1, further comprising: an interface unit (330) operably coupled with the control circuit to support communication with an external device, wherein the control circuit is configured to transmit a diagnosis result to an external device through the interface unit in response to the battery cell is diagnosed as exhibiting an abnormality.
The battery diagnosis apparatus according to claim 1, further comprising: an interface unit (330) operably coupled with the control circuit; and an output device (331) operably coupled with the interface unit, wherein the control circuit is configured to output a diagnosis result visually or audibly through the output device in response to the battery cell is diagnosed as exhibiting an abnormality.
A battery pack (B), comprising the battery diagnosis apparatus according to any one of claims 1 to 8.
A vehicle (1), comprising the battery pack according to claim 9.
A battery diagnosis method, comprising: recording time series data for a cell voltage of a battery cell in a storage medium; characterised by : determining, based on the time series data, a first voltage difference between a cell voltage measured at a first time and a cell voltage measured at a second and a second voltage difference between the cell voltage measured at the second time and a cell voltage measured at a third time; and diagnosing the battery cell based on the first voltage difference and the second voltage difference.
The battery diagnosis method according to claim 11, wherein the step of diagnosing the battery cell comprises diagnosing the battery cell based on the p square of the first voltage difference (p is a natural number of 1 or more) and the p square of the second voltage difference.
The battery diagnosis method according to claim 12, wherein the step of diagnosing the battery cell is performed based on whether a normal diagnosis condition where the p square of the first voltage difference is greater than the p square of the second voltage difference is established.
The battery diagnosis method according to claim 12, wherein the step of diagnosing the battery cell is performed based on a count number for which a normal diagnosis condition where the p square of the first voltage difference is greater than the p square of the second voltage difference is not established.
A computer-readable recording medium storing a program for causing a computer to perform the battery diagnosis method according to any one of claims 11 to 18.

Description

TECHNICAL FIELD The present disclosure relates to a technology for diagnosing a voltage abnormality of a battery. The present application claims priority to Korean Patent Application No. 10-2022-0117336 filed on September 16, 2022 in the Republic of Korea, the disclosure of which is incorporated herein by reference in its entirety. BACKGROUND ART 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, energy storage systems, robots and satellites, many studies are being made on high performance batteries that can be recharged repeatedly. Currently, commercially available batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium ion batteries and the like. 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. Recently, as applications requiring high voltage (e.g., energy storage systems, electric vehicles) become widespread, the need for diagnostic technology that accurately detects voltage abnormalities in each of the plurality of battery cells connected in series within a battery pack is increasing. The voltage abnormality of a battery cell refers to a fault condition in which the cell voltage drops and/or rises abnormally due to internal short-circuit, external short-circuit, failure of the voltage sensing line, or poor connection with the charging/discharging line. Conventionally, a simple method was used to diagnose a voltage abnormality of a battery cell by determining whether the difference between cell voltages measured at two different time points exceeds a threshold value. This method has the advantage of not requiring a high-performance processor because the amount of data calculation is not large. However, since the voltage of a battery cell also depends on temperature, current, and/or SOH (State Of Health) of the battery cell, it is not easy to accurately diagnose the voltage abnormality of the battery cell just through the process of comparing the difference of the voltages of the battery cell measured at different time points with the threshold value. In addition, if the voltage difference between the battery cells is lower than or equal to the threshold value but the voltage slope of the battery cell shows abnormal behavior, for example, when lithium plating (Li-plating) occurs on the negative electrode of a lithium battery, there is a limit in that an abnormality in cell voltage cannot be detected. DISCLOSURE Technical Problem The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a battery diagnosis apparatus, a battery diagnosis method, a battery pack, and a vehicle, which may efficiently and accurately diagnose a voltage abnormality of a battery cell using the tendency of a voltage change slope of the battery cell. These and other objects and advantages of the present disclosure may be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. Also, it will be easily understood that the objects and advantages of the present disclosure may be realized by the means shown in the appended claims and combinations thereof. Technical Solution In one aspect of the present disclosure, there is provided a battery diagnosis apparatus, comprising: a voltage sensing circuit configured to generate a voltage signal indicating a cell voltage of a battery cell; a storage medium configured to store time series data for the cell voltage; and a control circuit operably coupled with the voltage sensing circuit and the storage medium. The control circuit may be configured to (i) receive the voltage signal and record the time series data for the cell voltage in the storage medium, (ii) select kth, k+1th, and k+2th measured cell voltage set from the time series data as diagnostic data (k is an index indicating a measurement order of the cell voltage and is a natural number of 1 or more to which a plurality of values is assigned), (iii) determine a first voltage difference between the kth cell voltage and the k+1th cell voltage and a second voltage difference between the k+1th cell voltage and the k+2th cell voltage, and (iv) diagnose the battery cell as exhibiting a voltage abnormality, when, for a plurality of cell voltage sets, a count number of cell voltage sets for which a normal diagnosis condition where the p square of the first voltage difference (p is a natural number of 1 or more) is greater than the p square of the second voltage difference is not established is greater than or equal to a criterion value. The p may be 1 or a nat