KR-102964534-B1 - APPARATUS AND METHOD FOR DIAGNOSING BATTERY

KR102964534B1KR 102964534 B1KR102964534 B1KR 102964534B1KR-102964534-B1

Abstract

A battery diagnostic device according to one embodiment of the present invention includes: a measuring unit configured to measure the voltage and current of a battery; and a control unit configured to calculate a target discharge capacity until the voltage of the battery reaches a target voltage, calculate a full discharge capacity of the battery, calculate a capacity difference between the full discharge capacity and the target discharge capacity, calculate a rate of change in capacity difference based on the calculated capacity difference and a preset capacity difference profile, and diagnose the state of the battery based on the calculated rate of change in capacity difference and a preset reference rate of change.

Inventors

남기민
황태현
김형석

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260512
Application Date: 20230803

Claims (10)

A measuring unit configured to measure the voltage and current of the battery; and A battery diagnostic device characterized by including a control unit configured to calculate a target discharge capacity until the voltage of the battery reaches a target voltage, calculate a full discharge capacity of the battery, calculate a capacity difference between the full discharge capacity and the target discharge capacity, calculate a rate of change in capacity difference based on the calculated capacity difference and a preset capacity difference profile, and diagnose the state of the battery based on the calculated rate of change in capacity difference and a preset reference rate of change.
In paragraph 1, The above control unit is, If the above-calculated rate of change in capacity difference is less than the above-mentioned standard rate of change, the battery is configured to be diagnosed as being in a normal state, and A battery diagnostic device characterized by being configured to diagnose the state of the battery as abnormal if the calculated capacity difference change rate is greater than or equal to the reference change rate.
In paragraph 2, The above control unit is, The battery diagnosed as being in the above abnormal state is configured to be diagnosed as a battery at risk of sudden death, and A battery diagnostic device characterized by the fact that the above sudden death is a phenomenon in which poor contact or electrical disconnection occurs between the internal electrodes of the battery due to swelling.
In paragraph 1, The above control unit is, A battery diagnostic device characterized by being configured to determine the capacity difference at a previous point in time from the capacity difference profile above, and to calculate the capacity difference change rate by calculating the rate of change between the calculated capacity difference and the capacity difference at the previous point in time.
In paragraph 4, The above control unit is, A battery diagnostic device characterized by being configured to calculate the rate of change in capacity difference at the previous point in time based on the above capacity difference profile, and to set the value obtained by multiplying the rate of change in capacity difference at the previous point in time by a preset reference ratio as the reference rate of change.
In paragraph 5, The above standard ratio is, It is set as the ratio between the rate of change in capacity difference at the time when sudden death occurs in a preset reference battery and the rate of change in capacity difference at the time immediately before the sudden death occurs, and A battery diagnostic device characterized by the fact that the above sudden death is a phenomenon in which poor contact or electrical disconnection occurs between the internal electrodes of the above reference battery due to swelling.
In paragraph 1, The above target voltage is, A battery diagnostic device characterized in that, in the negative reference profile of a reference battery, the rate of change of negative potential with respect to capacity is preset to the voltage of the reference battery corresponding to the negative potential that is the same as the preset reference rate of change.
A battery pack comprising a battery diagnostic device according to any one of paragraphs 1 to 7.
An automobile comprising a battery diagnostic device according to any one of paragraphs 1 through 7.
A discharge capacity calculation step in which, by means of a control unit, a target discharge capacity is calculated until the voltage of the battery reaches a target voltage, and a full discharge capacity of the battery is calculated; A capacity difference calculation step for calculating the capacity difference between the maximum discharge capacity and the target discharge capacity by the above control unit; A step for calculating a capacity difference change rate based on a capacity difference calculated by the above control unit and a preset capacity difference profile; and A battery diagnosis method characterized by including a state diagnosis step for diagnosing the state of the battery based on a capacity difference change rate calculated by the control unit and a preset reference change rate.

Description

Apparatus and Method for Diagnosing Battery The present invention relates to a battery diagnostic device and method, and more specifically, to a battery diagnostic device and method capable of diagnosing the condition of a battery based on the capacity of the battery. Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, research on high-performance batteries capable of repeated charging and discharging is actively underway. Currently commercialized batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium batteries. Among these, lithium batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density. While much research is being conducted on these batteries in terms of increasing capacity and density, improving lifespan and safety is also important. To enhance battery safety, technology capable of accurately diagnosing the battery's current state is required. In particular, it is necessary to prevent the phenomenon of lithium deposition on the cathode surface (lithium plating, Li-plating). If lithium is deposited on the cathode surface, it causes adverse reactions with the electrolyte and alterations in the battery's kinetic balance, which leads to battery degradation. In addition, lithium plating can cause swelling of the battery. When swelling occurs, the center of the battery swells more than the edges, which can lead to an uneven pressure distribution. This results in a problem where the battery's performance deteriorates and a sudden death phenomenon occurs, where the electrical connection is instantly cut off. (References) (Reference 1) Published Patent Application No. 10-2022-0048371 (April 19, 2022) The following drawings attached to this specification serve to further enhance understanding of the technical concept of the invention in conjunction with the detailed description of the invention set forth below; therefore, the invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a schematic diagram illustrating a battery diagnostic device according to one embodiment of the present invention. FIG. 2 is a diagram illustrating a battery profile showing the corresponding relationship between the voltage and capacity of a battery according to one embodiment of the present invention. Figure 3 is a schematic diagram illustrating the capacity difference per cycle of an abnormal battery. Figure 4 is a schematic diagram illustrating the difference in capacity per cycle of a normal battery. FIG. 5 is a schematic diagram illustrating the difference in capacity at different time points of a battery according to one embodiment of the present invention. FIG. 6 is a schematic diagram illustrating the capacity difference and the rate of change in capacity difference at different time points of a battery according to one embodiment of the present invention. FIG. 7 is a schematic diagram illustrating the reference profile of a reference battery according to one embodiment of the present invention. FIG. 8 is a schematic diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention. FIG. 9 is a schematic diagram illustrating an exemplary configuration of a vehicle according to another embodiment of the present invention. FIG. 10 is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present invention. Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application. In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted. Terms including ordinal numbers, such as first, second, etc., are used for the purpose of distinguishing one of the various components from the rest, and are not used to limit the components by such terms. Throughout the specification, when