Battery testing device and operation method thereof

Abstract

A battery testing device according to one embodiment includes: a connector connected to an electrode of a battery cell; a charging / discharging unit configured to charge or discharge the battery cells through the connector; an ultrasonic sensing unit configured to output an ultrasonic signal toward the battery cell and sense an ultrasonic signal passing through the battery cell; and a controller configured to determine a state of the battery cell based on a characteristic of the ultrasonic signal passing through the battery cell during charging or discharging of the battery cell.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0082736 filed in the Korean Intellectual Property Office on July 5, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0004] Embodiments disclosed herein relate to a battery testing device and a method of operating the battery testing device. Background Art

[0005] Recently, research and development of secondary batteries have been actively carried out. Secondary batteries as rechargeable / dischargeable batteries can include all conventional nickel (Ni) / cadmium (Cd) batteries, Ni / metal hydride (MH) batteries, etc., and recent lithium-ion batteries. Among them, the energy density of lithium-ion batteries is much higher than that of conventional Ni / Cd batteries, Ni / MH batteries, etc. In addition, lithium-ion batteries can be made small and lightweight, so that lithium-ion batteries have been used as power sources for mobile devices, and recently, the use range of lithium-ion batteries has been expanded to power sources for electric vehicles, and has attracted much attention as the next generation of energy storage media.

[0006] The charge / discharge test refers to a method of testing the state of a battery by using state parameters of the battery obtained during charging or discharging of the battery (e.g., voltage, current, temperature, resistance change, etc.), and is widely used because it can monitor the remaining life or defects of a battery cell in a non-destructive manner. The clamp is used to electrically connect the electrode leads of the battery cell to the charger / discharger in the charge / discharge test, and the existing clamp, which is a member for simply transferring current to the battery cell, does not have an additional function for diagnosing the internal state of the battery cell. Summary of the invention

[0007] [Technical issues]

[0008] Embodiments disclosed herein are directed to providing a battery testing device that monitors changes in characteristics of ultrasonic signals passing through battery cells while performing a charge / discharge test of the battery cells, and determines a state of the battery cells based on the changes in the monitored characteristics of the ultrasonic signals.

[0009] Technical problems of the embodiments disclosed herein are not limited to the above-mentioned technical problems, and other unmentioned technical problems will be clearly understood by those of ordinary skill in the art from the following description.

[0010] [Technical solution]

[0011] A battery testing device according to one embodiment includes: a connector connected to an electrode of a battery cell; a charge / discharge unit configured to charge or discharge the battery cell through the connector; an ultrasonic sensing unit configured to output an ultrasonic signal toward the battery cell and sense the ultrasonic signal passing through the battery cell; and a controller configured to determine a state of the battery cell based on characteristics of the ultrasonic signal passing through the battery cell during charging or discharging of the battery cell.

[0012] In a battery testing device according to one embodiment, an ultrasonic sensing unit may include: an ultrasonic transmitter located inside a connector that contacts an electrode lead at one side of a battery cell and is configured to transmit an ultrasonic signal to the battery cell; and an ultrasonic receiver located inside a connector that contacts an electrode lead at an opposite side of the battery cell and is configured to receive an ultrasonic signal passing through the battery cell.

[0013] In the battery testing device according to one embodiment, the controller may be further configured to determine the state of the battery cell based on at least one of a velocity change and an amplitude change of the ultrasonic signal.

[0014] In the battery testing device according to one embodiment, the controller may be further configured to determine whether lithium is deposited inside the battery cell based on characteristics of the ultrasonic signal.

[0015] In the battery testing device according to one embodiment, the controller may be further configured to determine whether the electrode lead of the battery cell is defective based on characteristics of the ultrasonic signal.

[0016] In the battery testing device according to one embodiment, the controller may be further configured to calculate at least one of a charge state and a health state of the battery cell based on the characteristics of the ultrasonic signal and charge / discharge data of the battery cell.

[0017] The battery testing device according to one embodiment may further include a liquid injector configured to form an ultrasonic medium layer between the electrode leads of the battery cell and the connector.

[0018] An operating method of a battery testing device according to one embodiment includes: charging or discharging a battery cell through a connector connected to an electrode of the battery cell; outputting an ultrasonic signal toward the battery cell; sensing the ultrasonic signal passing through the battery cell; and determining a state of the battery cell based on characteristics of the ultrasonic signal passing through the battery cell during charging or discharging of the battery cell.

[0019] In an operating method of a battery testing device according to one embodiment, output of an ultrasonic signal toward a battery cell may be performed by an ultrasonic transmitter located inside a connector that contacts an electrode lead at one side of the battery cell, and output of an ultrasonic signal passing through the battery cell may be performed by an ultrasonic receiver located inside a connector that contacts an electrode lead at an opposite side of the battery cell.

[0020] In the operating method of the battery testing device according to one embodiment, determining the state of the battery cell may include determining the state of the battery cell based on at least one of a velocity change and an amplitude change of the ultrasonic signal.

[0021] In the operating method of the battery testing device according to one embodiment, determining the state of the battery cell may include determining whether lithium is precipitated inside the battery cell based on characteristics of the ultrasonic signal.

[0022] In the operating method of the battery testing device according to one embodiment, determining the state of the battery cell may include determining whether an electrode lead of the battery cell is defective based on characteristics of the ultrasonic signal.

[0023] In the operating method of the battery testing device according to one embodiment, determining the state of the battery cell may include calculating at least one of a charge state and a health state of the battery cell based on characteristics of the ultrasonic signal and charge / discharge data of the battery cell.

[0024] The operating method according to one embodiment may further include forming an ultrasonic medium layer between the electrode leads of the battery cell and the connector.

[0025] [Beneficial Effects]

[0026] With the battery testing device according to the embodiments disclosed herein, the state of the battery cell may be determined by using an ultrasonic transducer and an ultrasonic sensor included in a connector while charging / discharging the battery through a connector (eg, a clamp) connected to electrodes of the battery cell.

[0027] Conventional charge / discharge testers only use the electrical parameters of the battery cells to estimate the battery state, but according to one embodiment, the state of the cell can be more accurately estimated by using the characteristics of the ultrasonic signal passing through the battery cell as well as the electrical parameters, such as the charge state, health state, whether lithium is precipitated, whether the electrode lead is defective, etc.

[0028] Furthermore, various effects directly or indirectly recognized from the present disclosure can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly describe the embodiments disclosed herein or the technical solutions of the prior art, the following briefly introduces the drawings required in the description of the embodiments. It should be understood that the following drawings are for the purpose of explaining the embodiments of this specification rather than for limiting purposes. In addition, for the clarity of explanation, the representation of some components in the drawings may be exaggerated or omitted.

[0030] Figure 1 is a block diagram showing a configuration of a battery testing device according to one embodiment.

[0031] Figure 2 is a schematic diagram showing testing the state of a battery cell using a battery testing device according to an embodiment.

[0032] Figure 3 is a plan view showing a connector of a battery testing device according to one embodiment.

[0033] Figure 4a is a graph showing the change in the flight time required for an ultrasonic signal to pass through a battery cell with respect to the number of charge / discharge cycles.

[0034] Figure 4b is a graph showing the change in the amplitude of the ultrasonic signal passing through the battery cell with respect to the number of charge / discharge cycles.

[0035] Figure 5 is a flow chart illustrating an operating method of a battery testing device according to one embodiment.

[0036] Figure 6 A computing system for executing a battery testing method according to an embodiment disclosed herein is shown. DETAILED DESCRIPTION

[0037] Hereinafter, the embodiments disclosed in this document will be described in detail with reference to the exemplary drawings. When adding reference numerals to the components of each drawing, it should be noted that even if the same components are indicated in different drawings, they are given the same reference numerals. In addition, when describing the embodiments disclosed in this document, when it is determined that the detailed description of the related known configuration or function interferes with the understanding of the embodiments disclosed in this document, its detailed description will be omitted.

[0038] Although the terms used herein are selected using currently common general terms in consideration of the functions in the present disclosure, the terms may vary according to the intentions of those of ordinary skill in the art, customizations, or the introduction of new technologies. In addition, in certain cases, the applicant may voluntarily select words, and in this case, the meaning of the words may be disclosed in the corresponding description section of this specification. Therefore, the terms used herein should not be defined by the simple names of the terms, but by the essential meanings of the terms and content throughout the present disclosure. In addition, the terms defined in the present disclosure are only used to describe specific exemplary embodiments, and may not have the intention of limiting the scope of other exemplary embodiments. It should be understood that unless the context clearly provides otherwise, the singular form includes plural references.

[0039] Hereinafter, preferred embodiments of a battery testing device and an operating method thereof will be described with reference to the accompanying drawings.

[0040] The components shown in the block diagram are classified according to their functions and roles, and each box does not have to be implemented as independent hardware or software. For example, a separated component can actually be implemented as a device or program, or a component can be implemented as a combination of several devices and programs. In this article, expressions such as "first" and "second" are used to distinguish components from each other, and do not mean ranking or order among components.

[0041] Figure 1 is a block diagram showing a configuration of a battery testing device according to one embodiment, and Figure 2 1 is a schematic diagram showing a state in which a battery cell is tested using a battery testing device.

[0042] refer to Figure 1 , the battery testing device 100 may include: a connector 110 connected to an electrode of a battery cell 20; a charge / discharge unit 120 that charges or discharges the battery cell 20 through the connector 110; an ultrasonic sensing unit 130 that outputs an ultrasonic signal toward the battery cell 20 and senses the ultrasonic signal passing through the cell; and a controller 140 that determines the state of the battery cell 20 based on the characteristics of the ultrasonic signal. Although not shown, the battery testing device 10 may also include basic components for performing a charge / discharge test on a battery (e.g., power for charging, a load for discharging, wires for electrical connection between the battery cell and components, a control circuit for controlling the device, etc.).

[0043] The battery cell 20 may have various forms, and the battery to which the technology disclosed herein is applied is not limited to a specific form or configuration. For example, the battery cell 20 may have a structure in which a plurality of single cells (battery basic units including a positive electrode, a negative electrode, and a separator) are stacked and enclosed by a bag or a case, and may include electrode leads for electrically connecting the positive and negative electrodes of the battery cell to an external device. Figure 2 , a battery cell 20 and electrode leads 201 and 202 protruding outward from the battery cell 20 are shown.

[0044] The connector 110 may be a member for electrically connecting the battery testing device 10 to the battery cell 20 that contacts the electrode leads 201 and 202 of the battery cell 20. Figure 2 As shown, the connector may include a first contact portion 111 and a second contact portion 112 that contact the electrode leads 201 and 202 , respectively, and a portion that contacts the electrode leads may be formed of a metal material through which current flows.

[0045] For example, the connector 110 may be a holder for electrically contacting the battery cell electrodes in the charger / discharger. The contact portions 111 and 112 of the connector may have the form of a clip or a clamp including a spring to securely fix the electrode leads 201 and 202, respectively. The form of the connector shown is merely an example to help understanding, and may be changed to another appropriate form according to the shape of the battery cell or the position of the electrode.

[0046] According to one embodiment, the battery testing device 10 may further include a liquid injector (not shown) for forming an ultrasonic medium layer between the electrode leads 201 and 202 of the battery cell 20 and the contact portions 111 and 112 of the connector. The ultrasonic signal has a transmission speed and amplitude that vary with the medium, and when the electrode leads and the connector (e.g., the clamp) are not in close contact with each other, the characteristics of the signal are likely to be distorted due to the air gap. Therefore, the liquid injector may inject a water-soluble coupling agent between the electrode leads and the connector to compress them and allow the ultrasonic signal to pass through the battery cell without distorting the ultrasonic signal.

[0047] Return to reference Figure 1 , the charge / discharge unit 120 may charge or discharge the battery cell 20 by contacting the connector 110 of the battery cell 20. According to one embodiment, the charge / discharge unit 120 may be configured to measure the electrical parameters (current, voltage, impedance, etc.) of the battery cell 20 while charging or discharging the battery cell 20 at a preset C rate. The measured parameters may be transmitted to the controller 140 and may be used to estimate the state of the battery cell 20 together with or independently of the result of analyzing the ultrasonic signal.

[0048] The ultrasonic sensing unit 130 may include an ultrasonic transmitter that transmits an ultrasonic signal toward the battery cell 20 and an ultrasonic receiver that receives the ultrasonic signal passing through the battery cell 20. According to one embodiment, the ultrasonic transmitter may be an ultrasonic transducer including a piezoelectric element for converting an electrical signal provided from a power source into an ultrasonic signal, and the ultrasonic receiver may be an ultrasonic sensor for sensing the ultrasonic signal and converting the ultrasonic signal into an electrical signal. Although not shown, the ultrasonic sensing unit 130 may include additional components such as a power supply for driving the transducer and the sensor, a pulse generator, an oscilloscope, a switch, a control circuit for controlling them, and the like.

[0049] refer to Figure 2 , the ultrasonic transmitter 131 may be located inside the first contact portion 111 of the connector that contacts the electrode lead 201 at one side of the battery cell 20, and the ultrasonic receiver 132 may be located inside the second contact portion 112 of the connector that contacts the electrode lead 202 at the opposite side of the battery cell 20. Alternatively, both the ultrasonic transmitter and the ultrasonic receiver may be included in each of the first contact portion 111 and the second contact portion 112 of the connector to output ultrasonic waves or sense ultrasonic waves toward the corresponding transmitter / receiver. For example, as Figure 3 As shown, the first contact portion 111 of the connector may include both an ultrasonic transmitter 131 and an ultrasonic receiver 132 ′ for sensing an ultrasonic signal output from the ultrasonic transmitter positioned in the second contact portion 112 of the connector.

[0050] Return to reference Figure 2 When the ultrasonic transmitter 131 located in the connector 111 contacting the electrode lead 201 at one side outputs an ultrasonic signal toward the battery cell 20, the ultrasonic receiver 132 located in the connector 112 contacting the electrode lead 202 at the opposite side may detect the ultrasonic signal. The ultrasonic sensing unit 130 may obtain characteristic information of the ultrasonic signal, such as amplitude changes of the output ultrasonic signal and the sensed ultrasonic signal, flight time required for the ultrasonic signal to pass through the battery cell, etc., and transmit the characteristic information to the controller 140.

[0051] The controller 140 can determine the state of the battery cell 20 based on the characteristics of the ultrasonic signal sensed by the ultrasonic sensing unit 130 (e.g., speed change, amplitude change, etc. of the ultrasonic signal) or based on the characteristics of the ultrasonic signal and the charging / discharging data obtained from the charging / discharging unit 120 (e.g., current, voltage, impedance data, etc. of the battery cell).

[0052] According to one embodiment, the controller 140 may determine whether lithium is deposited inside the battery cell or whether the electrode lead of the battery cell is defective based on the characteristics of the ultrasonic signal. According to another embodiment, the controller 140 may calculate the state parameters of the battery cell, such as the state of charge, the state of health, etc., based on the characteristics of the ultrasonic signal and the charge / discharge data of the battery cell.

[0053] Figure 4a is a graph showing the change in the flight time required for an ultrasonic signal to pass through a battery cell relative to the number of charge / discharge cycles. ToF may be calculated based on the difference between the output time of the ultrasonic wave and the sensing time of the ultrasonic wave by the ultrasonic sensing unit 130. Figure 4a It can be seen that as the number of charge / discharge cycles increases (i.e., the remaining life decreases due to battery use), the ToF decreases overall. This is because as the battery is used continuously, the speed at which the ultrasonic signal passes through the battery cell increases due to lithium precipitation inside the cell, increased impedance, increased temperature, etc.

[0054] Figure 4b is a graph showing the change in the amplitude of the ultrasonic signal passing through the battery cell with respect to the number of charge / discharge cycles. Figure 4b It can be seen that as the number of charge / discharge cycles increases (i.e., the remaining life decreases due to battery use), the amplitude of the ultrasonic signal increases overall. This is because as the battery is continuously used, the intensity of the ultrasonic signal passing through the battery cell increases due to lithium precipitation inside the cell, increased impedance, increased temperature, etc.

[0055] According to one embodiment, when charging or discharging of the battery cell 20 is performed by the charging / discharging unit 120 , the state of the battery cell may be estimated more accurately based on the characteristics of the ultrasonic signal measured by the ultrasonic sensing unit 130 .

[0056] More specifically, defects such as initial lithium precipitation of a battery cell may be observed in a specific charging section, but the precipitated metal may dissolve and disappear after the corresponding section. In this case, the abnormality may not be diagnosed by a general ultrasonic test performed separately from the charge / discharge test of the battery cell, but according to one embodiment, the charge / discharge test and the ultrasonic test may be performed simultaneously by an ultrasonic sensor for charge / discharge test provided in a connector, thereby making the diagnosis easy.

[0057] Furthermore, ultrasonic testing is typically performed by contacting an ultrasonic transducer with a main body portion of a battery cell, wherein in particular, a pouch-type battery may have internal defects due to deformation during compression of the transducer and the battery, and applying a coupling agent directly to the surface of the cell may not be desirable in terms of marketability.

[0058] According to one embodiment, the clamp can be coupled to the electrode lead portion instead of the surface of the cell to apply the ultrasonic signal, thereby solving the above-mentioned problem and providing a technical advantage, so that not only the internal defects of the cell but also the defects of the electrode or defects related to other components can be tested.

[0059] According to the above-mentioned battery testing device, by simultaneously performing a charge / discharge test and an ultrasonic test on a battery using a connector including an ultrasonic sensor, the state of the battery cell (lithium precipitation, electrode lead defect, remaining life, etc.) can be determined based on the charge / discharge data and the characteristics of the ultrasonic signal.

[0060] Figure 5 FIG. 1 is a flow chart showing an operation method of a battery testing device according to an embodiment. Figures 1 to 3 Components of a battery testing apparatus 10 and a battery 20 are described.

[0061] refer to Figure 5 , in operation S100, an ultrasonic medium layer may be formed between the electrode of the battery cell and the connector. Operation S100 may be selectively performed by a liquid injector before or after the connector is brought into contact with the electrode of the battery cell. Since the ultrasonic signal has a transmission speed and amplitude that vary with the medium, when the electrode lead and the connector are not in close contact with each other, the characteristics of the signal are likely to be distorted due to the air gap. Therefore, a water-soluble coupling agent may be injected between the electrode and the connector to compress them, and the ultrasonic signal may be allowed to pass through the battery cell without distorting the ultrasonic signal.

[0062] In operation S200, the battery cell may be charged or discharged through a connector connected to an electrode of the battery cell. According to one embodiment, the connector may be a clamp for fixing the battery electrode in a battery charger / discharger and the charger / discharger in a connected state, and a portion contacting the electrode may be formed of a metal material through which current flows.

[0063] According to one embodiment, the charge / discharge unit may measure electrical parameters (current, voltage, impedance, etc.) of the battery cell while charging or discharging the battery cell at a preset C-rate. The measured parameters may be transmitted and may be used to determine the state of the battery cell together with or independently of the results of analyzing the ultrasonic signal.

[0064] In operation S300, an ultrasonic signal may be output toward the battery cell. According to one embodiment, operation S300 may be performed by an ultrasonic transmitter located inside a first contact portion of the connector contacting an electrode lead at one side of the battery cell (see Figure 2 and Figure 3The ultrasonic transmitter may be an ultrasonic transducer including a piezoelectric element for converting an electrical signal supplied from a power source into an ultrasonic signal.

[0065] In operation S400, an ultrasonic signal passing through the battery cell may be sensed. According to one embodiment, operation S400 may be performed by an ultrasonic receiver located inside a second contact portion of the connector that contacts the electrode lead at the opposite side of the battery cell (see Figure 2 and Figure 3 ) is performed, and the ultrasonic receiver may be an ultrasonic sensor for sensing an ultrasonic signal and converting the ultrasonic signal into an electrical signal.

[0066] In operation S500 , during charging or discharging of the battery cell, a state of the battery cell may be determined based on characteristics of an ultrasonic signal sensed after passing through the battery cell.

[0067] According to one embodiment, the operation S500 of determining the state of the battery cell may include an operation of determining the state of the battery cell based on characteristics of the ultrasonic signal, such as speed change, amplitude change, etc. of the ultrasonic signal. For example, the ultrasonic sensing unit may obtain characteristic information of the ultrasonic signal, such as amplitude change of the output ultrasonic signal and the sensed ultrasonic signal, flight time required for the ultrasonic signal to pass through the battery cell, etc., and the controller may estimate the state of the battery cell based on the characteristic information.

[0068] According to one embodiment, the operation S500 of determining the state of the battery cell may include an operation of determining whether lithium is deposited inside the battery cell or whether an electrode lead of the battery cell is defective based on the characteristics of the ultrasonic signal (e.g., speed change, amplitude change, etc. of the ultrasonic signal). According to another embodiment, the state parameters of the battery cell, such as the state of charge, the state of health, etc., may be calculated based on the characteristics of the ultrasonic signal and the charge / discharge data of the battery cell (e.g., the current, voltage, impedance data, etc. of the battery cell).

[0069] As referenced above Figure 4a and Figure 4b As described, since the characteristics of the ultrasonic signal may change as the number of charge / discharge cycles of the battery cell increases (i.e., the remaining life decreases due to battery usage), the state of the battery cell can be more accurately estimated by using characteristic information such as the time it takes the ultrasonic signal to pass through the battery cell (ToF), changes in amplitude, etc., as well as charge / discharge data.

[0070] More specifically, by analyzing the change in the ultrasonic signal during the charge or discharge of the battery cell, an abnormality that may be observed only in some charging sections, such as initial lithium precipitation, can be detected. In this case, the abnormality may not be diagnosed by a general ultrasonic test performed separately from the charge / discharge test of the battery cell, but using the test method according to one embodiment, the charge / discharge test and the ultrasonic test can be performed simultaneously by an ultrasonic sensor for the charge / discharge test provided in the connector, thereby making the diagnosis easy.

[0071] Figure 6 is a plan view showing a hardware configuration of a battery testing device according to one embodiment.

[0072] refer to Figure 6 The battery testing device 10 may include a microcontroller (MCU) 1010 that performs various processes and controls each component, a memory 1020 in which an operating system program and various programs are recorded, an input / output interface 1030 that provides an input interface and an output interface between a battery cell module and / or a semiconductor switching element, and a communication interface 1040 that can communicate with an external device through a wired / wireless communication network. Therefore, a computer program for executing the battery testing device may be recorded in the memory 1020 and processed by the microcontroller 1010, thereby being implemented to execute Figure 1 and 2 The modules are shown in the functional boxes.

[0073] The operating method of the battery testing device according to this embodiment can be implemented in the form of an application or program instruction that can be executed by various computer components and recorded in a computer-readable recording medium. The computer-readable recording medium can include program instructions, data files, data structures, etc. alone or in combination.

[0074] So far, all the components constituting this embodiment have been described as being combined or operating in combination, but are not necessarily limited to this embodiment, and within the scope of this purpose, all the components may be selectively combined with one or more components to operate. In addition, the above-mentioned terms such as "including", "consisting of", "having", etc. may mean that the corresponding components may be inherent, unless otherwise specified, and therefore should be interpreted as also including other components rather than excluding other components.

[0075] The above description merely illustrates the technical concept of the present disclosure, and a person skilled in the art to which the embodiments disclosed herein pertain will be able to make various modifications and changes without departing from the basic characteristics of the embodiments of the present disclosure.

[0076] Therefore, the embodiments disclosed herein are intended to describe rather than limit the technical spirit of the embodiments disclosed herein, and the scope of the technical spirit of the present disclosure is not limited by these embodiments disclosed herein. The protection scope of the technical spirit disclosed herein should be interpreted by the attached claims, and all technical spirits within the same scope should be understood to be included in the scope of the present disclosure.

Claims

1. A battery testing device, comprising: A connector connected to an electrode of a battery cell; a charging / discharging unit configured to charge or discharge the battery cell through the connector; an ultrasonic sensing unit configured to output an ultrasonic signal toward the battery cell and sense the ultrasonic signal passing through the battery cell; as well as A controller is configured to determine a state of the battery cell based on characteristics of the ultrasonic signal passing through the battery cell during charging or discharging of the battery cell.

2. The battery testing device according to claim 1, wherein the ultrasonic sensing unit comprises: an ultrasonic transmitter located inside the connector contacting the electrode lead at one side of the battery cell and configured to transmit the ultrasonic signal to the battery cell; as well as An ultrasonic receiver is located inside the connector contacting the electrode leads at opposite sides of the battery cell and is configured to receive the ultrasonic signal passing through the battery cell. 3 . The battery testing device of claim 1 , wherein the controller is further configured to determine the state of the battery cell based on at least one of a velocity change and an amplitude change of the ultrasonic signal. 4 . The battery testing device of claim 3 , wherein the controller is further configured to determine whether lithium is deposited inside the battery cell based on the characteristic of the ultrasonic signal. 5 . The battery testing device of claim 3 , wherein the controller is further configured to determine whether the electrode lead of the battery cell is defective based on the characteristics of the ultrasonic signal. 6 . The battery testing device of claim 3 , wherein the controller is further configured to calculate at least one of a state of charge and a state of health of the battery cell based on the characteristics of the ultrasonic signal and charge / discharge data of the battery cell. 7 . The battery testing device according to claim 1 , further comprising a liquid injector configured to form an ultrasonic medium layer between the electrode leads of the battery cell and the connector.

8. A method for operating a battery testing device, the method comprising: charging or discharging the battery cells via connectors connected to electrodes of the battery cells; outputting an ultrasonic signal toward the battery cell; sensing an ultrasonic signal passing through the battery cell; as well as During charging or discharging of the battery cell, a state of the battery cell is determined based on characteristics of the ultrasonic signal passing through the battery cell.

9. The operating method according to claim 8, wherein the output of the ultrasonic signal toward the battery cell is performed by an ultrasonic transmitter located inside the connector contacting an electrode lead at one side of the battery cell, and The output of the ultrasonic signal passing through the battery cell is performed by an ultrasonic receiver located inside the connector contacting electrode leads at opposite sides of the battery cell. 10 . The operating method of claim 8 , wherein determining the state of the battery cell comprises determining the state of the battery cell based on at least one of a velocity change and an amplitude change of the ultrasonic signal. 11 . The operating method according to claim 10 , wherein determining the state of the battery cell comprises determining whether lithium is deposited inside the battery cell based on the characteristic of the ultrasonic signal.

12. The operating method according to claim 10, wherein: Determining the state of the battery cell includes determining whether the electrode lead of the battery cell is defective based on the characteristics of the ultrasonic signal.

13. The operating method according to claim 10, wherein: Determining the state of the battery cell includes calculating at least one of a state of charge and a state of health of the battery cell based on the characteristics of the ultrasonic signal and charge / discharge data of the battery cell. 14 . The operating method according to claim 8 , further comprising forming an ultrasonic medium layer between the electrode lead of the battery cell and the connector.

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