Method and apparatus for analyzing deformation of secondary battery

Abstract

Disclosed are a method and an apparatus for analyzing deformation of a secondary battery having an electrode assembly housed in a case. The method includes obtaining a first image by performing computed tomography (CT) imaging on the secondary battery, calculating a first sum value of a long diameter and a short diameter of the case from the first image, obtaining a number of charging and discharging cycles of the secondary battery after charging and discharging the secondary battery a plurality of times to deteriorate the secondary battery, and calculating a second sum value of the long diameter and the short diameter of the case from the second image. A second image is obtained by performing CT imaging on the degraded secondary battery, a second summation value of the long diameter and the short diameter of the case is calculated from the second image, and deformation of the electrode assembly is determined if a value obtained by subtracting the first summation value from the second summation value is greater than a reference value.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2023-0136716 filed in the Korean Intellectual Property Office on October 13, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a method and apparatus for analyzing deformation of a secondary battery. Background Art

[0004] Secondary batteries are subjected to continuous charging and discharging, which causes various electrochemical reactions within the battery, leading to battery degradation and performance degradation. In particular, the internal deformation of the battery during charging and discharging is the main factor affecting battery degradation and performance degradation. In order to analyze the degradation phenomenon, destructive analysis methods are mainly used, which usually involve disassembling the battery and analyzing it. However, this analysis method inevitably causes damage to the interior of the battery during the disassembly process, making it difficult to determine the actual cause of performance degradation, and is limited in identifying the degradation trend as charging and discharging proceed.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure. Summary of the invention

[0006] Embodiments include a method for analyzing deformation of a secondary battery having an electrode assembly housed in a housing. The method includes obtaining a first image by performing computed tomography (CT) imaging on the secondary battery, calculating a first summation value of a long diameter and a short diameter of the housing from the first image, obtaining the number of charge and discharge cycles of the secondary battery after charging and discharging the secondary battery multiple times to degrade the secondary battery, obtaining a second image by performing CT imaging on the degraded secondary battery, calculating a second summation value of a long diameter and a short diameter of the housing from the second image, and determining that the electrode assembly is deformed if a value obtained by subtracting the first summation value from the second summation value is greater than a reference value.

[0007] Obtaining the first image may include obtaining a first area image corresponding to the first area and a second area image corresponding to the second area by performing CT imaging on each of the first area and the second area of ​​the secondary battery, and wherein the method further includes: calculating the long diameter of the first area of ​​the shell from the first area image, calculating the long diameter of the second area of ​​the shell from the second area image, and if the absolute value obtained by subtracting the long diameter of the first area from the long diameter of the second area is greater than a reference value, determining that the electrode assembly is deformed.

[0008] Obtaining the second image may include obtaining a first region image corresponding to the first region and a second region image corresponding to the second region by performing CT imaging on each of the first region and the second region of the degraded secondary battery, and wherein the method further includes: calculating the long diameter of the first region of the shell from the first region image, calculating the long diameter of the second region of the shell from the second region image, and if the absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, determining that the electrode assembly is deformed.

[0009] The housing may have a cylindrical shape.

[0010] The electrode assembly may be wound into a cylindrical shape in which a positive electrode plate, a separator, and a negative electrode plate are stacked.

[0011] The first region and the second region may be spaced apart from each other in a direction along a winding axis of the electrode assembly.

[0012] An embodiment includes a method for analyzing deformation of a secondary battery having an electrode assembly housed in a housing. The method includes obtaining a first region image corresponding to the first region and a second region image corresponding to the second region by performing computed tomography (CT) imaging on a first region and a second region of the secondary battery, respectively, calculating a long diameter of the first region of the housing from the first region image, calculating a long diameter of the second region of the housing from the second region image, and determining that the electrode assembly is deformed if an absolute value obtained by subtracting a long diameter of the first region from a long diameter of the second region is greater than a reference value.

[0013] The method may further include calculating a first summed value of a long diameter and a short diameter of the shell from the first area image, obtaining the number of charge and discharge cycles of the secondary battery after charging and discharging the secondary battery multiple times to degrade the secondary battery, obtaining a second image of the first area by performing CT imaging on the degraded secondary battery, calculating a second summed value of a long diameter and a short diameter of the shell from the second image of the first area, and determining that the electrode assembly is deformed if a value obtained by subtracting the first summed value from the second summed value is greater than a reference value.

[0014] The method may further include calculating a first summed value of a long diameter and a short diameter of the shell from the second area image, obtaining the number of charge and discharge cycles of the secondary battery after charging and discharging the secondary battery multiple times to degrade the secondary battery, obtaining a second image of the second area by performing CT imaging on the degraded secondary battery, calculating a second summed value of a long diameter and a short diameter of the shell from the second image of the second area, and determining that the electrode assembly is deformed if a value obtained by subtracting the first summed value from the second summed value is greater than a reference value.

[0015] Embodiments include a device for analyzing the deformation of a secondary battery having an electrode assembly housed in a housing. The device includes a control circuit, a processor installed in the control circuit, and a memory installed in the control circuit and operably connected to the processor. The processor executes a program code stored in the memory and is configured to obtain a first image by performing computed tomography (CT) imaging on the secondary battery, calculate a first sum of the long diameter and the short diameter of the housing from the first image, obtain the number of charge and discharge cycles of the secondary battery after charging and discharging the secondary battery multiple times to degrade the secondary battery, obtain a second image by performing CT imaging on the degraded secondary battery, calculate a second sum of the long diameter and the short diameter of the housing from the second image, and if the value obtained by subtracting the first sum from the second sum is greater than a reference value, determine that the electrode assembly is deformed.

[0016] Obtaining the first image includes: obtaining a first area image corresponding to the first area and a second area image corresponding to the second area by performing CT imaging on each of the first area and the second area of ​​the secondary battery, and wherein the processor executes a program code stored in the memory and is further configured to: calculate the long diameter of the first area of ​​the shell from the first area image, calculate the long diameter of the second area of ​​the shell from the second area image, and if the absolute value obtained by subtracting the long diameter of the first area from the long diameter of the second area is greater than a reference value, determine that the electrode assembly is deformed.

[0017] Obtaining the second image includes: obtaining a first area image corresponding to the first area and a second area image corresponding to the second area by performing CT imaging on each of the first area and the second area of ​​the secondary battery, and wherein the processor executes a program code stored in the memory and is further configured to: calculate the long diameter of the first area of ​​the shell from the first area image, calculate the long diameter of the second area of ​​the shell from the second area image, and if the absolute value obtained by subtracting the long diameter of the first area from the long diameter of the second area is greater than a reference value, determine that the electrode assembly is deformed.

[0018] The housing may have a cylindrical shape.

[0019] The electrode assembly may be wound into a cylindrical shape in which a positive electrode plate, a separator, and a negative electrode plate are stacked.

[0020] The first region and the second region may be spaced apart from each other in a direction along a winding axis of the electrode assembly.

[0021] An embodiment includes an apparatus for analyzing deformation of a secondary battery having an electrode assembly housed in a housing. The apparatus includes a control circuit, a processor installed in the control circuit, and a memory installed in the control circuit and operably connected to the processor, wherein the processor can execute a program code stored in the memory and can be configured to obtain a first region image corresponding to the first region and a second region image corresponding to the second region by performing computed tomography (CT) imaging on the first region and the second region of the secondary battery, respectively, calculate the long diameter of the first region of the housing from the first region image, calculate the long diameter of the second region of the housing from the second region image, and if the absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, determine that the electrode assembly is deformed.

[0022] The processor can execute program code stored in the memory and can be further configured to calculate a first summed value of the long diameter and the short diameter of the shell from the first area image, obtain the number of charge and discharge cycles of the secondary battery after charging and discharging the secondary battery multiple times to degrade the secondary battery, obtain a second image of the first area by performing CT imaging on the degraded secondary battery, calculate a second summed value of the long diameter and the short diameter of the shell from the second image of the first area, and determine that the electrode assembly is deformed if a value obtained by subtracting the first summed value from the second summed value is greater than a reference value.

[0023] The processor can execute program code stored in the memory and can be further configured to calculate a first summed value of the long diameter and the short diameter of the shell from the second area image, obtain the number of charge and discharge cycles of the secondary battery after charging and discharging the secondary battery multiple times to degrade the secondary battery, obtain a second image of the second area by performing CT imaging on the degraded secondary battery, calculate a second summed value of the long diameter and the short diameter of the shell from the second image of the second area, and determine that the electrode assembly is deformed if a value obtained by subtracting the first summed value from the second summed value is greater than a reference value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Features will become apparent to those having ordinary skill in the art by describing exemplary embodiments in detail with reference to the accompanying drawings.

[0025] Figure 1 is a block diagram illustrating a configuration of an apparatus for analyzing deformation of an exemplary secondary battery according to one or more embodiments of the present disclosure.

[0026] Figure 2A and Figure 2B is a flow chart illustrating a method for analyzing deformation of an exemplary secondary battery according to one or more embodiments of the present disclosure.

[0027] Figure 3A and Figure 3B are longitudinal and cross-sectional views of an exemplary secondary battery according to one or more embodiments of the present disclosure.

[0028] Figure 4A is a graph showing the degree of swelling (unit: mm) of a secondary battery with respect to the number of charge and discharge cycles of an exemplary secondary battery.

[0029] Figure 4B is a graph showing a difference (unit: mm) in long diameters of upper and lower ends of a secondary battery with respect to the number of charge and discharge cycles of an exemplary secondary battery according to one or more embodiments of the present disclosure.

[0030] Figure 5A and Figure 5B is a graph showing a swelling degree (unit: %) of a secondary battery with respect to the number of charge and discharge cycles of an exemplary secondary battery according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0031] In the accompanying drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It is also understood that when a layer or element is referred to as being "on" another layer or substrate, it may be directly on the other layer or substrate, or there may be intervening layers. Further, it is understood that when a layer is referred to as being "below" another layer, it may be directly below the other layer, or there may be one or more intervening layers. In addition, it is also understood that when a layer is referred to as being "between" two layers, it may be the only layer between the two layers, or there may be one or more intervening layers. The same reference numerals refer to the same elements throughout.

[0032] In addition, the control unit (controller) and / or other related devices or components according to the present disclosure can be implemented by using any appropriate hardware, firmware (e.g., dedicated semiconductors), software, or an appropriate combination of software, firmware, and hardware. For example, the control unit (controller) and / or other related devices or components according to the present disclosure can be formed on a single integrated circuit chip, or formed in a separate integrated circuit chip. In addition, the various components of the control unit (controller) can be implemented on a flexible printed circuit film, and can be formed on a substrate that is the same as a tape carrier package, a printed circuit board, or a control unit (controller). In addition, the various components of the control unit (controller) can be processes or threads that run on one or more processors in one or more computing devices, execute computer program instructions, and interact with other system components for performing various functions described below. Computer program instructions can be stored in a memory, which can be implemented in a computing device using a standard memory device such as, for example, a random access memory (RAM). Computer program instructions can also be stored in other non-transient computer-readable media such as, for example, a CD-ROM, a flash drive, etc. In addition, those of ordinary skill in the art should recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the spirit and scope of the exemplary embodiments of the present disclosure.

[0033] Figure 1 1 is a block diagram showing the configuration of an apparatus for analyzing deformation of an exemplary secondary battery (also referred to as a deformation analysis apparatus) 100 according to one or more embodiments of the present disclosure. Figure 1 As shown in FIG. 1 , a deformation analysis device 100 for a secondary battery according to one or more embodiments of the present disclosure may include an input device 101, an output device 102, a control circuit 103, a central processing unit (CPU) 104, a memory 105, and a program code 106. In some embodiments, the deformation analysis device 100 may further include a CT imaging device 107 and / or a charging / discharging device 108.

[0034] The control circuit 103 may execute the program code 106 stored in the memory 105 through the CPU 104, and may control the overall operation of the deformation analysis device 100. In some embodiments, the program code 106 may include an image analysis tool (e.g., "ImageJ"), which is open source software for image analysis available for download online.

[0035] The deformation analysis device 100 may receive data or information input by a user through an input device 101 (e.g., a keyboard or a mouse), and output an image or sound through an output device 102 (e.g., a display or a speaker). In some embodiments, the deformation analysis device 100 may directly or indirectly receive a CT image from a CT imaging device 107. In one or more embodiments, the deformation analysis device 100 may directly or indirectly receive the number of charge and discharge cycles from a charge / discharge device 108. In some embodiments, the deformation analysis device 100 may receive data in pairs of a CT image and the number of charge and discharge cycles.

[0036] In the memory 105 , various settings (eg, reference values ​​or reference ratios) for implementing the embodiments of the present disclosure, received CT images, the number of received charge and discharge cycles, and a program code 106 for controlling the operation of the deformation analysis device 100 may be stored.

[0037] The CT imaging device 107 can obtain a CT image by performing CT imaging on the secondary battery, and transmit the CT image directly or indirectly to the deformation analysis device 100. In some embodiments, the CT imaging device 107 can be controlled by direct control of the control circuit 103, so that the control circuit 103 can directly obtain or receive an image from the CT imaging device 107. In an embodiment, the image obtained from the CT imaging device 107 can be indirectly provided to the control circuit 103 through the input device 101.

[0038] The charging / discharging device 108 can charge the secondary battery by providing current and voltage to the secondary battery to be subjected to CT imaging, or can discharge the secondary battery by connecting a load to the secondary battery. In some embodiments, the charging / discharging device 108 can be controlled by direct control of the control circuit 103, so that the control circuit 103 can directly obtain or receive the number of charging and discharging cycles from the charging / discharging device 108. In one or more embodiments, the number of charging and discharging cycles obtained from the charging / discharging device 108 can be indirectly provided to the control circuit 103 through the input device 101.

[0039] In some embodiments, a CT image for each charge and discharge cycle of the secondary battery may be provided in the form of mutually matching data to the control circuit 103. In other words, whenever a charge and discharge cycle of the secondary battery passes, CT imaging may be performed on the secondary battery, and thus data including the number of charge and discharge cycles and the CT image may be provided directly or indirectly to the control circuit 103.

[0040] Figure 2A and Figure 2Bis a flow chart illustrating a method for analyzing deformation of an exemplary secondary battery according to one or more embodiments of the present disclosure.

[0041] As in Figure 2A As shown in , the method for analyzing the deformation of an exemplary secondary battery according to an embodiment of the present disclosure may include obtaining a first image by performing CT imaging on the secondary battery (step S11) (which may be the first step), calculating a first sum of the long diameter and the short diameter of the shell (step S12) (which may be the second step), obtaining the number of charge and discharge cycles of the secondary battery (step S13) (which may be the third step), obtaining a second image by performing CT imaging on a degraded secondary battery (step S14) (which may be the fourth step), calculating a second sum of the long diameter and the short diameter of the shell (step S15) (which may be the fifth step), and if the difference between the first sum and the second sum is greater than a reference value, determining that the secondary battery is deformed (step S16) (which may be the sixth step).

[0042] In some embodiments, the long diameter may be referred to as the major axis, and the short diameter may be referred to as the minor axis. In geometry, the major axis and the minor axis of a deformed or distorted circle may represent two perpendicular diameters of an ellipse. An ellipse is a closed curve in which the sum of the distances from a point on the curve to two fixed points (called foci) remains constant. The longer diameter of an ellipse may be referred to as the major axis, and the shorter diameter may be referred to as the minor axis. That is, the major axis is the longest diameter of the ellipse, which passes through the center and the two foci, and its length may be the major diameter. In addition, the minor axis may be a minor diameter perpendicular to the major axis, which passes through the center like the major axis, and its length may be the minor axis diameter.

[0043] Generally speaking, in a perfectly symmetrical circle, the major axis and the minor axis can be the same because the distance through the center always remains the same no matter from which direction it is measured. However, in the modified cylindrical shell described in the present disclosure (assuming an elliptical shell), the lengths of the major axis and the minor axis can be different because their shapes are stretched or compressed. Therefore, in the present disclosure, the term "major diameter" can refer to the longer diameter of the ellipse corresponding to the major axis, and the term "minor diameter" can refer to the shorter diameter corresponding to the minor axis.

[0044] In step S11, the control circuit 103 may obtain or receive the first image from the CT imaging device 107. In some embodiments, the secondary battery may be CT imaged by the CT imaging device 107, and the captured first image may be transmitted from the CT imaging device 107 to the control circuit 103. As described above, the CT imaging device 107 may operate in response to a control signal from the control circuit 103 or may operate independently to directly or indirectly transmit the first image to the control circuit 103.

[0045] In step S12, the control circuit 103 can measure the long diameter and the short diameter of the shell from the first image, and calculate the first sum of the long diameter and the short diameter. In some embodiments, the long diameter refers to the longest diameter among the diameters of the shell, the short diameter refers to the shortest diameter among the diameters of the shell, and the long diameter and the short diameter can intersect each other. In addition, the long diameter and the short diameter obtained from the first image can be defined as or referred to as the initial long diameter of the shell and the initial short diameter of the shell.

[0046] In step S13, the control circuit 103 may obtain or receive the number of charge and discharge cycles of the secondary battery from the charge / discharge device 108. In one or more embodiments, the secondary battery may be charged and discharged multiple times by the charge / discharge device 108, and the number of cycles after charging and discharging may be transmitted from the charge / discharge device 108 to the control circuit 103. As described above, the charge / discharge device 108 may be operated by a control signal from the control circuit 103 or may be independently operated to charge and discharge the secondary battery multiple times, and may directly or indirectly transmit the number of charge and discharge cycles to the control circuit 103. In some embodiments, the secondary battery may deteriorate or age due to the charging and discharging of the secondary battery, and the housing and / or electrode assembly of the secondary battery may be deformed.

[0047] In step S14, the control circuit 103 may obtain or receive the second image from the CT imaging device 107. In one or more embodiments, the degraded secondary battery may be CT imaged by the CT imaging device 107, and the captured second image may be transmitted from the CT imaging device 107 to the control circuit 103. As described above, the CT imaging device 107 may be operated by a control signal from the control circuit 103 or may be independently operated to transmit the second image directly or indirectly to the control circuit 103.

[0048] In step S15, the control circuit 103 can measure the long diameter and short diameter of the shell from the second image, and can calculate a second summation value of the long diameter and the short diameter. In an embodiment, the long diameter and the short diameter obtained from the second image can be defined as or referred to as the long diameter of the shell by life and the short diameter of the shell by life. In other words, the long diameter and the short diameter obtained from the second image can be interpreted as the long diameter of the shell by cycle and the short diameter of the shell by cycle, respectively.

[0049] In step S16, if the difference between the first summation value and the second summation value (e.g., a value obtained by subtracting the first summation value from the second summation value) is greater than a preset reference value, the control circuit 103 may determine that the interior (e.g., the housing and / or the electrode assembly) has been deformed. In some embodiments, the control circuit 103 may output the first image, the second image, the first summation value, the second summation value, the difference between the first summation value and the second summation value, the reference value, and the occurrence of deformation through the output device 102.

[0050] Figure 2B , a flow chart showing a method for analyzing deformation of an exemplary secondary battery (also referred to as a deformation analysis method) according to one or more embodiments of the present disclosure. The deformation analysis method may include obtaining an image by performing CT imaging on the secondary battery (step S21) (which may be a first step), calculating the long diameter of the first area of ​​the shell (step S22) (which may be a second step), calculating the long diameter of the second area of ​​the shell (step S23) (which may be a third step), and if the absolute value of the difference between the long diameters of the shell is greater than a reference value, determining that the secondary battery is deformed (step S24) (which may be a fourth step).

[0051] In step S21, the control circuit 103 may obtain or receive a first region image corresponding to the first region of the secondary battery and a second region image corresponding to the second region of the secondary battery from the CT imaging device 107. In some embodiments, the first region of the secondary battery may be an upper region of the secondary battery, and the second region of the secondary battery may be a lower region of the secondary battery.

[0052] In step S22 , the control circuit 103 may measure and calculate the long diameter of the first region of the shell from the first region image.

[0053] In step S23 , the control circuit 103 may measure and calculate the long diameter of the second region of the shell from the second region image.

[0054] In step S24, if the absolute value of the difference between the long diameters of the shell is greater than the reference value, the control circuit 103 may determine that the shell and / or the electrode assembly of the secondary battery are deformed. In one or more embodiments, the control circuit 103 may output the first region image, the second region image, the long diameter of the first region, the long diameter of the second region, the difference (e.g., absolute value) between the long diameter of the first region and the long diameter of the second region, the reference value, and the occurrence of deformation through the output device 102.

[0055] Various embodiments of the deformation analysis method of a secondary battery according to the present disclosure are explained below.

[0056] [Preparation of Secondary Battery]

[0057] A cylindrical secondary battery having a jelly-roll-type electrode assembly housed in a cylindrical case (or a cylindrical can) may be first prepared.

[0058] Figure 3A and Figure 3B are a longitudinal view and a cross-sectional view of an exemplary secondary battery. Figure 3B The electrode assembly is greatly exaggerated to illustrate the winding state of the electrode assembly. In reality, the center of the electrode assembly has an approximately circular empty space (or core), and there is almost no empty space between the outside of the electrode assembly and the inner surface of the shell (or can). In practice, the electrode assembly is wound into an approximately perfect circle, and Figure 3B The winding structure is shown exaggerated to illustrate the winding structure as described above. In addition, a person skilled in the art will understand that the corresponding Figure 3B CT images and Figure 3B The shadows in are opposite.

[0059] In one or more embodiments, the jellyroll-shaped electrode assembly 30 of the secondary battery 1 may be housed in a cylindrical case 10 and may be manufactured by coupling the cap assembly 20 to the open top end of the cylindrical case 10 after injecting an electrolyte to immerse the electrode assembly 30 in the cylindrical case 10 (optional). In an embodiment, the electrode assembly 30 may be in the form of a jellyroll manufactured by stacking a positive electrode plate 31 and a negative electrode plate 32 with a separator 33 interposed therebetween and then winding in one direction. Figure 3B In the embodiment of the present invention, 30S refers to the winding front end portion where the winding of the electrode assembly 30 starts, and 30E refers to the winding tail end portion where the winding of the electrode assembly 30 ends. In some embodiments, the phrases "winding front end portion" and "winding tail end portion" may refer to specific areas during the manufacturing process of the electrode assembly. The process may involve the generation of a wound or rolled electrode structure commonly used in batteries (e.g., lithium-ion battery cells). Specifically, in a circular electrode assembly of a secondary battery, the winding front end portion may refer to the initial portion or point where the winding of the electrode plate starts. This may be where the first layer of the electrode plate is attached to the central core or diaphragm or is wound around the central core or diaphragm. In a circular electrode assembly of a secondary battery, the winding tail end portion may refer to the last portion or point where the winding process ends. This may be where the last layer of the electrode plate is attached and secured. In order to ensure that the electrode plate is securely fixed and has no loose ends or edges, it is important to properly terminate the winding process at the winding tail end portion. Because the contents of the positive plate, negative plate, diaphragm and electrolyte are known to those skilled in the art, their detailed description will be omitted.

[0060] In an embodiment, the cylindrical housing 10 may be made of a metal such as steel (e.g., stainless steel or nickel-plated steel). In one or more embodiments, the cylindrical housing may include a receiving component in which the electrode assembly may be accommodated, and its upper portion may be opened. In some embodiments, a curved curling portion may be provided to be sealed after the cap assembly 20 is coupled to the opened upper portion of the cylindrical housing 10, and in order to make the cap assembly 20 safe, the upper end may be bent to provide a curling portion. In one or more embodiments, the curling portion may be provided at a portion where the cap assembly and the cylindrical housing contact each other, and may be recessed toward the inner side of the cylindrical housing. In some embodiments, the cylindrical housing may be used as a negative electrode terminal for connection to an external circuit. In an embodiment, the cap assembly 20 may be constructed so that the cap and the safety vent are in close contact with an airtight gasket, which is mounted in a space formed on the inner surface of the curling portion and the curling portion of the cylindrical housing 10. The central portion of the cap may protrude upward, and therefore may be used as a positive electrode terminal for connection to an external circuit. In one or more embodiments, a core 34 in the form of an empty space may be provided at the center of the electrode assembly 30 wound in a jelly roll configuration. In some embodiments, a center pin (not shown) made of a cylindrical metal material may be inserted into the core 34 to provide additional strength to the electrode assembly, and in some cases, the center pin may be removed after the electrode assembly is welded to the cylindrical case or cap assembly. In an embodiment, a negative electrode tab may protrude from the lower end of the electrode assembly and be welded to the bottom surface of the cylindrical case, and a positive electrode tab may protrude from the upper end of the electrode assembly and be welded to the cap assembly.

[0061] In one or more embodiments, the CT imaged area of ​​the secondary battery 1 may include a first area adjacent to the cap assembly and / or a second area adjacent to the bottom surface of the can. In other words, the first area may be approximately the upper portion of the can and the electrode assembly, and the second area may be approximately the lower portion of the can and the electrode assembly. In some embodiments, the CT imaged area may further include a third area, which may be approximately the middle portion of the can and the electrode assembly.

[0062] In an embodiment, the present disclosure may also be applied to 18650 (18 mm diameter, 65 mm height) cylindrical batteries, 21700 (21 mm diameter, 70 mm height) cylindrical batteries, or 46800 (46 mm diameter, 80 mm height) cylindrical batteries, and may also be applied to cylindrical batteries to be manufactured in the future.

[0063] [First CT imaging]

[0064] When a cylindrical secondary battery is prepared in the above manner, a first image of a cross section perpendicular to the winding axis of the electrode assembly can be obtained by a CT imaging device. In some embodiments, the first image may be a first area image obtained by photographing a first area of ​​the secondary battery (e.g., the upper portion of the housing and the electrode assembly). In one or more embodiments, the first image may be a second area image obtained by photographing a second area of ​​the secondary battery (e.g., the lower portion of the housing and the electrode assembly). In an embodiment, the first image may be a third area image obtained by photographing a third area of ​​the secondary battery (e.g., the middle portion of the housing and the electrode assembly).

[0065] In some embodiments, the CT imaging device 107 may include a fixture on which the secondary battery is mounted, an X-ray irradiator for irradiating X-rays to the secondary battery, and an X-ray detector for detecting X-rays transmitted through the secondary battery. The first region image, the second region image, and the third region image obtained from the CT imaging device may be directly or indirectly transmitted to the control circuit 103 of the secondary battery deformation analysis device 100, and the computer or processor may obtain the first region image, the second region image, and the third region image corresponding to the first region, the second region, and the third region of the secondary battery, respectively, from the transmitted X-rays, and then store them.

[0066] In one or more embodiments, the CT imaging device 107 may obtain only the first region image corresponding to the first region of the secondary battery, obtain only the second region image corresponding to the second region, or obtain only the third region image corresponding to the third region. In some embodiments, the CT imaging device 107 may obtain only the first region image and the second region image of the secondary battery, obtain only the first region image and the third region image, or obtain only the second region image and the third region image.

[0067] [Calculation of the first sum value]

[0068] In an embodiment, the control circuit 103 may measure the long diameter and short diameter of the shell from the first region image and calculate a first sum of the long diameter and the short diameter. In some embodiments, the control circuit 103 may measure the long diameter and short diameter of the shell from the second region image and calculate a first sum of the long diameter and the short diameter. In one or more embodiments, the control circuit 103 may measure the long diameter and short diameter of the shell from the third region image and calculate a first sum of the long diameter and the short diameter.

[0069] [Performance of charge and discharge cycle of secondary battery]

[0070] The secondary battery can be charged and discharged by the charging / discharging device 108. When the secondary battery is charged and discharged once, it can be defined as one cycle or one life of the secondary battery has passed. In some embodiments, an image can be obtained from the CT imaging device every time the secondary battery is cycled by the charging / discharging device for about 50 to about 100 times.

[0071] The charging / discharging device 108 may include a fixture on which the secondary battery is mounted, a charging circuit connected to the secondary battery to provide charging power, a discharging circuit connected to the secondary battery and operating as a load, a positive electrode pin and a negative electrode pin connecting the charging circuit and the discharging circuit to the positive electrode terminal and the negative electrode terminal of the secondary battery, respectively, and a computer or processor capable of storing the charging / discharging time, the charging / discharging voltage, the charging / discharging current, and the number of cycles. The number of cycles obtained from the charging / discharging device can be directly or indirectly transmitted to the control circuit 103 of the deformation analysis device 100 of the secondary battery. In some embodiments, without the intervention of the charging / discharging device 108, if the image obtained from the CT imaging device 107 is transmitted to the control circuit 103, the number of cycles can also be manually input through the input device.

[0072] [Second CT imaging]

[0073] As described above, after the secondary battery deteriorates as the charge and discharge cycle of the secondary battery proceeds, a second image of a cross section perpendicular to the winding axis of the electrode assembly can be obtained by a CT imaging device. In one or more embodiments, the second image may be a first area image obtained by photographing a first area of ​​the secondary battery (e.g., the upper portion of the housing and the electrode assembly). In some embodiments, the second image may be a second area image obtained by photographing a second area of ​​the secondary battery (e.g., the lower portion of the housing and the electrode assembly). In an embodiment, the second image may be a third image obtained by photographing a third area of ​​the secondary battery (e.g., the middle portion of the housing and the electrode assembly). The image obtained from the CT imaging device may be transmitted directly or indirectly to the control circuit 103 of the deformation analysis device 100 of the secondary battery.

[0074] [Calculation of the second sum value]

[0075] In some embodiments, the control circuit 103 may measure the long diameter and short diameter of the shell from the first regional image and calculate the second sum of the long diameter and the short diameter. In one or more embodiments, the control circuit 103 may measure the long diameter and short diameter of the shell from the second regional image and calculate the second sum of the long diameter and the short diameter. In an embodiment, the control circuit 103 may measure the long diameter and short diameter of the shell from the third regional image and calculate the second sum of the long diameter and the short diameter.

[0076] [Determination of deformation of secondary battery]

[0077] In the present disclosure, the determination of the deformation of the secondary battery may be performed in various ways.

[0078] [1. Use expansion degree (unit: mm) to determine deformation]

[0079] (1) In some embodiments, if the difference between the first summation value and the second summation value (e.g., a value obtained by subtracting the first summation value from the second summation value) is greater than a preset reference value, it can be determined that the interior of the secondary battery (e.g., the housing or the electrode assembly) is deformed. In one or more embodiments, if the first image and the second image are obtained, the number of charge and discharge cycles can also be obtained. Accordingly, it can be determined whether the secondary battery is deformed as the number of cycles of the secondary battery elapses. In some embodiments, the first image and the second image can be obtained from the same area of ​​the secondary battery (e.g., one of the first area, the second area, and the third area), and the first summation value and the second summation value can also be calculated in the same area of ​​the secondary battery.

[0080] (2) In one or more embodiments, instead of including the steps of calculating the first summation value and the second summation value, the initial long diameter of the shell can be calculated from the first image, and the long diameter by life or by cycle of the shell can be calculated from the second image. Thereafter, if the value obtained by subtracting the initial long diameter of the first image from the long diameter by life of the second image is greater than a reference value, the internal deformation of the secondary battery can be determined. In some embodiments, the first image and the second image can be obtained from the same area of ​​the secondary battery (e.g., one of the first area, the second area, and the third area), and the initial long diameter and the long diameter by life can also be measured in the same area of ​​the secondary battery.

[0081] (3) In an embodiment, instead of including the step of calculating the first summation value and the second summation value, the initial short diameter of the shell can be calculated from the first image, and the short diameter of the shell by life or by cycle can be calculated from the second image. Thereafter, if the value obtained by subtracting the initial short diameter of the second image from the short diameter by life of the second image is greater than a reference value, the internal deformation of the secondary battery can be determined. In some embodiments, the first image and the second image can be obtained from the same area of ​​the secondary battery (e.g., one of the first area, the second area, and the third area), and the initial short diameter and the short diameter by life can also be measured in the same area of ​​the secondary battery.

[0082] [2. Use expansion degree (unit: %) to determine deformation]

[0083] (1) In one or more embodiments, instead of including the steps of calculating the first summation value and the second summation value, the initial long diameter of the shell can be calculated from the first image, and the long diameter of the shell by life or by cycle can be calculated from the second image. Thereafter, if the ratio of the initial long diameter of the first image to the long diameter by life of the second image (e.g., (long diameter by life of the second image / initial long diameter of the first image)×100%) is greater than a reference value, the internal deformation of the secondary battery can be determined. In some embodiments, the first image and the second image can be obtained from the same area of ​​the secondary battery (e.g., one of the first area, the second area, and the third area), and the initial long diameter and the long diameter by life can also be measured in the same area of ​​the secondary battery.

[0084] (2) In an embodiment, instead of including the step of calculating a first summation value and a second summation value, an initial short diameter of the shell may be calculated from the first image, and a short diameter by life or by cycle of the shell may be calculated from the second image. Thereafter, if a ratio of the initial short diameter of the first image to the short diameter by life of the second image (e.g., (short diameter by life of the second image / initial short diameter of the first image)×100%) is greater than a reference value, the internal deformation of the secondary battery may be determined. In some embodiments, the first image and the second image may be obtained from the same region of the secondary battery (e.g., one of the first region, the second region, and the third region), and the initial short diameter and the short diameter by life may also be measured in the same region of the secondary battery.

[0085] (3) In one or more embodiments, instead of including a step of subtracting the first summation value from the second summation value, if the ratio of the first summation value to the second summation value (e.g., (second summation value based on life / initial first summation value)×100%) is greater than a preset reference ratio, the internal deformation of the secondary battery can be determined.

[0086] (4) In some embodiments, instead of including the steps of calculating a first summation value and a second summation value, if the ratio of a short diameter by life of the second image to a long diameter by life of the second image (e.g., (short diameter by life of the second image / long diameter by life of the second image)×100%) is greater than a preset reference ratio, the internal deformation of the secondary battery can be determined.

[0087] (5) In an embodiment, instead of including the steps of calculating a first summation value and a second summation value, if a ratio of an initial short diameter of the first image to an initial long diameter of the first image (e.g., (initial short diameter of the first image / initial long diameter of the first image)×100%) is greater than a preset reference ratio, the internal deformation of the secondary battery can be determined.

[0088] [3. Use the expansion degree (unit: %) according to the height of the battery cell (upper part / middle part / lower part) to determine the deformation]

[0089] (1) In some embodiments, if the ratio of the expansion degree of the first region to the expansion degree of the third region (e.g., the expansion degree of the upper portion / the expansion degree of the middle portion) is greater than a preset reference ratio, the internal deformation of the secondary battery can be determined. In some embodiments, the expansion degree can be obtained from the above-mentioned item "2. Determining deformation using the expansion degree (unit: %)".

[0090] (2) In one or more embodiments, if the ratio of the expansion degree of the third region to the expansion degree of the second region (e.g., the expansion degree of the middle portion / the expansion degree of the lower portion) is greater than a preset reference ratio, the internal deformation of the secondary battery can be determined. In some embodiments, the expansion degree can be obtained from the above-mentioned item "2. Determining deformation using the expansion degree (unit: %)".

[0091] (3) In an embodiment, if the ratio of the expansion degree of the first region to the expansion degree of the second region (e.g., the expansion degree of the upper portion / the expansion degree of the lower portion) is greater than a preset reference ratio, the internal deformation of the secondary battery can be determined. In some embodiments, the expansion degree can be obtained from the above-mentioned item "2. Determining deformation using the expansion degree (unit: %)".

[0092] [4. Deformation determination method using the difference in long diameter (unit: mm) according to the height of the battery cell (upper part / middle part / lower part)]

[0093] (1) In some embodiments, if the difference between the long diameter of the first region and the long diameter of the second region (e.g., the long diameter of the upper portion minus the long diameter of the lower portion) is greater than a preset reference value, the internal deformation of the secondary battery may be determined. This determination method may be combined with a reference value. Figure 2B The methods described are similar or identical to their corresponding descriptions.

[0094] (2) In one or more embodiments, if the difference between the long diameter of the first region and the long diameter of the third region (e.g., the long diameter of the upper portion minus the long diameter of the middle portion) is greater than a preset reference value, the internal deformation of the secondary battery may be determined. This determination method may be combined with a reference value. Figure 2B The methods described are similar or identical to their corresponding descriptions.

[0095] (3) In some embodiments, if the difference between the long diameter of the third region and the long diameter of the second region (e.g., the long diameter of the middle portion minus the long diameter of the lower portion) is greater than a preset reference value, the internal deformation of the secondary battery may be determined. This determination method may be combined with a reference value. Figure 2B The methods described are similar or identical to their corresponding descriptions.

[0096] [5. Deformation determination method using the difference in short diameter (unit: mm) according to the height of the battery cell (upper part / middle part / lower part)]

[0097] (1) In one or more embodiments, if the difference between the short diameter of the first region and the short diameter of the second region (e.g., the short diameter of the upper portion minus the short diameter of the lower portion) is greater than a preset reference value, the internal deformation of the secondary battery may be determined. This determination method may be combined with a reference value. Figure 2B The methods described are similar or identical to their corresponding descriptions.

[0098] (2) In some embodiments, if the difference between the short diameter of the first region and the short diameter of the third region (e.g., the short diameter of the upper portion minus the short diameter of the middle portion) is greater than a preset reference value, the internal deformation of the secondary battery may be determined. This determination method may be combined with a reference value. Figure 2B The methods described are similar or identical to their corresponding descriptions.

[0099] (3) In an embodiment, if the difference between the short diameter of the third region and the short diameter of the second region (e.g., the short diameter of the middle portion minus the short diameter of the lower portion) is greater than a preset reference value, the internal deformation of the secondary battery may be determined. This determination method may be combined with the reference value. Figure 2B The methods described are similar or identical to their corresponding descriptions.

[0100] The reference value or reference ratio may vary depending on the electrochemical characteristics, size, use environment, etc. of the secondary battery.

[0101] In general, if there is no deformation in the electrode assembly, the long diameter and / or short diameter of the shell will not change despite the increase in the number of charge and discharge cycles of the secondary battery. However, as the number of charge and discharge cycles of the secondary battery increases, the electrode assembly repeatedly expands and contracts, and thus the electrode assembly may be deformed. In view of this, in the present disclosure, as the number of charge and discharge cycles of the secondary battery increases, the change value or change rate of the long diameter and / or short diameter of the shell can be measured, and if the change value or change rate is greater than a predetermined reference value or reference rate, it can be determined that the shell and / or electrode assembly is deformed.

[0102] In addition, even without considering the number of charge and discharge cycles of the secondary battery, if there is no deformation in the electrode assembly, the long diameter and / or short diameter between the upper part, the lower part and / or the middle part of the shell will be the same or similar. However, if there is internal deformation in the secondary battery, there will be a difference in the long diameter and / or short diameter between the upper part, the lower part and / or the middle part of the shell. Taking this into account, in the present disclosure, without considering the number of charge and discharge cycles of the secondary battery, if the difference (e.g., absolute value) of the long diameter and / or short diameter between the upper part, the lower part and / or the middle part of the shell is greater than a reference value, it can be determined that the shell and / or the electrode assembly are deformed.

[0103] Figure 4A is a graph showing the degree of swelling (unit: mm) of a secondary battery with respect to the number of charge and discharge cycles of an exemplary secondary battery according to one or more embodiments. Figure 4A , the horizontal axis indicates the number of charge and discharge cycles, the vertical axis indicates the expansion degree (mm), A1 represents the first secondary battery, and A2 represents the second secondary battery. In addition, the expansion degree (mm) may mean a major diameter difference.

[0104] As in Figure 4A As shown in , it can be seen that the expansion degree (long diameter difference) of the first secondary battery and the second secondary battery generally increases with the increase in the number of charge and discharge cycles. In some embodiments, if the expansion degree is greater than about 0.1 mm, it can be determined that the secondary battery is deformed.

[0105] Figure 4B is a graph showing the difference (unit: mm) in the long diameters of the upper and lower ends of a secondary battery with respect to the number of charge and discharge cycles of an exemplary secondary battery according to one or more embodiments. Figure 4B , the horizontal axis indicates the number of charge and discharge cycles, the vertical axis indicates the major diameter difference (mm) between the upper end and the lower end, A1 represents the first secondary battery, and A2 represents the second secondary battery.

[0106] As in Figure 4B As shown in , it can be seen that the difference in long diameter between the upper end and the lower end generally increases with the increase in the number of charge and discharge cycles. In some embodiments, if the difference in long diameter is greater than about -0.01 mm, it can be determined that the secondary battery is deformed.

[0107] Figure 5A and Figure 5B is a graph showing the degree of swelling (unit: %) of a secondary battery relative to the number of charge and discharge cycles of an exemplary secondary battery. Figure 5A and Figure 5B , the horizontal axis indicates the number of charge and discharge cycles, and the vertical axis indicates the degree of swelling (%).

[0108] As in Figure 5A and Figure 5B As shown in FIG. 1 , with reference to the ratio of the long diameter of the shell according to life to the initial long diameter of the shell and the ratio of the short diameter of the shell according to life to the initial short diameter of the shell, it can be seen that the expansion degree gradually increases with the increase in the number of charge and discharge cycles. In some embodiments, if the expansion degree is greater than about 100.5%, it can be determined that the secondary battery is deformed.

[0109] As described above, in the method and apparatus for analyzing the deformation of a secondary battery, according to an embodiment of the present disclosure, an image of the long diameter and / or short diameter of the shell in a direction perpendicular to the winding axis of the electrode assembly can be obtained, and it can be determined from the image whether the shell and / or the electrode assembly are deformed according to the difference in the long diameter and / or short diameter. Therefore, according to an embodiment of the present disclosure, it is possible to accurately determine whether the shell and / or the electrode assembly provided in the secondary battery are deformed in a non-destructive manner without disassembling the secondary battery.

[0110] As described above, the present disclosure provides a method (a non-destructive analysis method) and an apparatus for analyzing the deformation of a secondary battery, by which the internal deformation of the secondary battery can be accurately diagnosed by using a CT (computed tomography) image.

[0111] Exemplary embodiments have been disclosed herein, and although specific terms are used, they are used and interpreted in a general and descriptive sense only and not for purposes of limitation. In some cases, as will be apparent to one of ordinary skill in the art when this application is filed, unless otherwise specifically indicated, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments. Accordingly, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the claims.

Claims

1. A method for analyzing deformation of a secondary battery having an electrode assembly accommodated in a case, the method comprising: obtaining a first image by performing computed tomography imaging on the secondary battery; calculating a first sum of a major diameter and a minor diameter of the shell from the first image; after charging and discharging the secondary battery a plurality of times to deteriorate the secondary battery, obtaining the number of charge and discharge cycles of the secondary battery; obtaining a second image by performing computed tomography imaging of the degraded secondary battery; calculating a second sum of the major diameter and the minor diameter of the shell from the second image; as well as If a value obtained by subtracting the first summed value from the second summed value is greater than a reference value, it is determined that the electrode assembly is deformed.

2. The method according to claim 1, wherein: The obtaining of the first image comprises: By performing computed tomography imaging on each of a first region and a second region of the secondary battery, a first region image corresponding to the first region and a second region image corresponding to the second region are obtained; and Wherein, the method further comprises: calculating a major diameter of the first region of the shell from the first region image; calculating a major diameter of the second region of the shell from the second region image; and If an absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, it is determined that the electrode assembly is deformed.

3. The method according to claim 1, wherein: The obtaining of the second image comprises: By performing computed tomography imaging on each of a first region and a second region of the degraded secondary battery, a first region image corresponding to the first region and a second region image corresponding to the second region are obtained; and Wherein, the method further comprises: calculating a major diameter of the first region of the shell from the first region image; calculating a major diameter of the second region of the shell from the second region image; and If an absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, it is determined that the electrode assembly is deformed.

4. The method according to claim 1, wherein: The housing has a cylindrical shape.

5. The method according to claim 1, wherein: The electrode assembly is wound into a cylindrical shape in which a positive electrode plate, a separator, and a negative electrode plate are stacked.

6. The method according to claim 2, wherein: The first region and the second region are spaced apart from each other in a direction along a winding axis of the electrode assembly.

7. The method according to claim 3, wherein: The first region and the second region are spaced apart from each other in a direction along a winding axis of the electrode assembly.

8. A method for analyzing deformation of a secondary battery having an electrode assembly accommodated in a case, the method comprising: obtaining a first region image corresponding to the first region and a second region image corresponding to the second region by performing computed tomography imaging on the first region and the second region of the secondary battery, respectively; calculating a major diameter of the first region of the shell from the first region image; calculating a major diameter of the second region of the shell from the second region image; as well as If an absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, it is determined that the electrode assembly is deformed.

9. The method according to claim 8, further comprising: Calculating a first sum of a major diameter and a minor diameter of the shell from the first region image; after charging and discharging the secondary battery a plurality of times to deteriorate the secondary battery, obtaining the number of charge and discharge cycles of the secondary battery; obtaining a second image of the first region by performing computed tomography imaging of the degraded secondary battery; calculating a second sum of the major diameter and the minor diameter of the shell from the second image of the first area; as well as If a value obtained by subtracting the first summed value from the second summed value is greater than a reference value, it is determined that the electrode assembly is deformed.

10. The method according to claim 8, further comprising: Calculating a first sum of a major diameter and a minor diameter of the shell from the second region image; after charging and discharging the secondary battery a plurality of times to deteriorate the secondary battery, obtaining the number of charge and discharge cycles of the secondary battery; obtaining a second image of the second region by performing computed tomography imaging of the degraded secondary battery; calculating a second sum of the major diameter and the minor diameter of the shell from the second image of the second area; as well as If a value obtained by subtracting the first summed value from the second summed value is greater than a reference value, it is determined that the electrode assembly is deformed.

11. An apparatus for analyzing deformation of a secondary battery having an electrode assembly accommodated in a housing, the apparatus comprising: Control circuit; a processor installed in the control circuit; as well as a memory installed in the control circuit and operably coupled to the processor, wherein the processor executes program code stored in the memory and is configured to: obtaining a first image by performing computed tomography imaging on the secondary battery; calculating a first sum of a major diameter and a minor diameter of the shell from the first image; after charging and discharging the secondary battery a plurality of times to deteriorate the secondary battery, obtaining the number of charge and discharge cycles of the secondary battery; obtaining a second image by performing computed tomography imaging of the degraded secondary battery; calculating a second sum of the major diameter and the minor diameter of the shell from the second image; and If a value obtained by subtracting the first summed value from the second summed value is greater than a reference value, it is determined that the electrode assembly is deformed.

12. The device according to claim 11, wherein The obtaining of the first image comprises: By performing computed tomography imaging on each of a first region and a second region of the secondary battery, a first region image corresponding to the first region and a second region image corresponding to the second region are obtained; and The processor executes the program code stored in the memory and is further configured to: calculating a major diameter of the first region of the shell from the first region image; calculating a major diameter of the second region of the shell from the second region image; and If an absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, it is determined that the electrode assembly is deformed.

13. The device according to claim 11, wherein: The obtaining of the second image comprises: By performing computed tomography imaging on each of a first region and a second region of the degraded secondary battery, a first region image corresponding to the first region and a second region image corresponding to the second region are obtained; and The processor executes the program code stored in the memory and is further configured to: calculating a major diameter of the first region of the shell from the first region image; calculating a major diameter of the second region of the shell from the second region image; and If an absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, it is determined that the electrode assembly is deformed.

14. The device according to claim 11, wherein: The housing has a cylindrical shape.

15. The device according to claim 11, wherein The electrode assembly is wound into a cylindrical shape in which a positive electrode plate, a separator, and a negative electrode plate are stacked.

16. The device according to claim 12, wherein: The first region and the second region are spaced apart from each other in a direction along a winding axis of the electrode assembly.

17. The device according to claim 13, wherein: The first region and the second region are spaced apart from each other in a direction along a winding axis of the electrode assembly.

18. An apparatus for analyzing deformation of a secondary battery having an electrode assembly accommodated in a case, the apparatus comprising: Control circuit; a processor installed in the control circuit; as well as a memory installed in the control circuit and operably coupled to the processor, The processor executes program code stored in the memory and is configured to: Obtaining a first region image corresponding to the first region and a second region image corresponding to the second region by performing computed tomography imaging on a first region and a second region of the secondary battery respectively; calculating a major diameter of the first region of the shell from the first region image; calculating a major diameter of the second region of the shell from the second region image; and If an absolute value obtained by subtracting the long diameter of the first region from the long diameter of the second region is greater than a reference value, it is determined that the electrode assembly is deformed.

19. The device according to claim 18, wherein: The processor executes the program code stored in the memory and is further configured to: Calculating a first sum of a major diameter and a minor diameter of the shell from the first region image; after charging and discharging the secondary battery a plurality of times to deteriorate the secondary battery, obtaining the number of charge and discharge cycles of the secondary battery; obtaining a second image of the first region by performing computed tomography imaging of the degraded secondary battery; calculating a second sum of the major diameter and the minor diameter of the shell from the second image of the first area; as well as If a value obtained by subtracting the first summed value from the second summed value is greater than a reference value, it is determined that the electrode assembly is deformed.

20. The device according to claim 18, wherein The processor executes the program code stored in the memory and is further configured to: Calculating a first sum of a major diameter and a minor diameter of the shell from the second region image; after charging and discharging the secondary battery a plurality of times to deteriorate the secondary battery, obtaining the number of charge and discharge cycles of the secondary battery; obtaining a second image of the second region by performing computed tomography imaging of the degraded secondary battery; calculating a second sum of the major diameter and the minor diameter of the shell from the second image of the second area; as well as If a value obtained by subtracting the first summed value from the second summed value is greater than a reference value, it is determined that the electrode assembly is deformed.

Images