Battery cell evaluation method and battery cell evaluation device

Abstract

A battery evaluation method according to one embodiment of the present invention comprises: a step of forming a pouch film to form a storage portion on which an electrode assembly is mounted; a step of applying an impact to at least one of the corners of the storage portion; a step of storing the pouch film inside a second container together with a first container containing an electrolyte; and a step of detecting whether the outer layer of the pouch film has peeled off.

Description

Technology Field

[0001] The present invention relates to a battery cell evaluation method and a battery cell evaluation device, and more specifically, to a battery cell evaluation method and a battery cell evaluation device with improved accuracy regarding whether the outer layer of a pouch film has peeled off. Background Technology

[0002] With the increasing technological development and demand for mobile devices, the demand for secondary batteries as an energy source is rapidly rising. Among these secondary batteries, lithium secondary batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rate, have been commercialized and are widely used.

[0003] A pouch for secondary batteries is primarily used as an outer material for packaging such secondary batteries, and the pouch is generally a pouch film composed of an outer layer, an adhesive layer, an aluminum layer, an adhesive layer, and an inner layer. However, pouch-type secondary batteries can be damaged during various processes. For example, during the process of mounting an electrode assembly inside the pouch, damage such as cracks may occur in the inner layer of the pouch, and consequently, the aluminum layer within the pouch film may be exposed. In this case, the aluminum layer may be exposed to the electrolyte inside the pouch and corrode, which leads to the problem of corrosive gas generation.

[0004] Figure 1 is a diagram showing the electrolyte injection process during the battery cell manufacturing process. Figure 2 is a diagram showing the degas and resealing processes after the electrolyte injection process of Figure 1.

[0005] Referring to FIG. 1, in the battery cell manufacturing process, an electrolyte injection process is performed in which an electrolyte is injected while an electrode assembly is mounted in the storage portion of a pouch (100), and then a temporary sealing portion (A) is formed at one end of the pouch (100). Afterward, referring to FIG. 2, after the electrolyte process, a hole (B) is formed on one side of the pouch to remove gas generated inside the pouch, and then a degas process is performed to remove the gas, and then a resealing process is performed to form a sealing portion (C) on the pouch film.

[0006] Here, during the degas process as shown in Fig. 2, the inside of the pouch is made into a vacuum and a hole (B) is formed, so that an impact can be applied to the corner of the storage portion formed in the pouch. Accordingly, during the degas process and resealing process, there was a problem in which the outer layer of the pouch adjacent to the corner of the storage portion came into direct contact with the electrolyte or was exposed to an electrolyte atmosphere.

[0007] However, in the case of conventional battery cell evaluation methods, the resistance to electrolyte is evaluated by impregnating a pouch film into a container containing electrolyte, and while it is possible to evaluate cases where the electrolyte directly contacts the pouch film, it was difficult to accurately evaluate whether the outer layer of the pouch delaminates during the process described above. Accordingly, there is a need to develop a battery cell evaluation method with improved accuracy that takes into account situations occurring during the battery cell manufacturing process. The problem to be solved

[0008] The problem to be solved by the present invention is to provide a battery cell evaluation method and a battery cell evaluation device with improved accuracy regarding whether the outer layer of a pouch film has peeled off.

[0009] The problems that the present invention aims to solve are not limited to those described above, and problems not mentioned will be clearly understood by those skilled in the art from this specification and the attached drawings. means of solving the problem

[0010] A battery cell evaluation method according to one embodiment of the present invention comprises: a step of forming a pouch film to form a storage portion on which an electrode assembly is mounted; a step of applying an impact to at least one of the corners of the storage portion; a step of storing the pouch film inside a second container together with a first container containing an electrolyte; and a step of detecting whether the outer layer of the pouch film has peeled off.

[0011] The first container is open toward the second container, and the second container may be sealed from the outside air.

[0012] At least some of the above electrolyte may be evaporated inside the second container.

[0013] The method may further include the step of storing the second container in a chamber maintained under high temperature and high humidity conditions.

[0014] The interior of the chamber can be maintained at a temperature of 40 to 80 degrees Celsius.

[0015] The interior of the chamber can be maintained at a humidity of 70%RH to 99%RH.

[0016] The second container can be stored in the chamber for 1 to 28 days.

[0017] The first container above may contain a solution in which water is mixed with the electrolyte.

[0018] The second container can be stored in the chamber for 5 to 12 hours.

[0019] The step of applying impact to the storage portion further includes the step of mounting a jig portion that is recessed identical to the shape of the storage portion onto the storage portion, and can apply impact to the storage portion through the jig portion.

[0020] The above jig part can apply impact to the above storage part for a time of 0.1 minutes to 1 minute with a speed of 40 mm / min to 60 mm / min and a force of 0.5 N to 1.5 N.

[0021] A battery cell evaluation device according to another embodiment of the present invention comprises: a jig portion for applying impact to at least one corner of a storage portion formed in a pouch film on which an electrode assembly is mounted; a storage portion for storing the pouch film, which has been impacted from the jig portion, inside a second container together with a first container containing an electrolyte; and a detection portion for determining whether the outer layer of the pouch film has peeled off.

[0022] The above jig portion includes a main body portion and a recessed portion capable of accommodating the storage portion, and the recessed portion may be recessed toward the bottom surface relative to the outer surface of the main body portion.

[0023] The above-mentioned recess may have a size equal to or larger than the above-mentioned storage portion.

[0024] Notches may be formed at each corner of the above-mentioned depression.

[0025] The above notch may be formed in a circular shape.

[0026] The above jig part can apply impact to the above storage part for a time of 0.1 minutes to 1 minute with a speed of 40 mm / min to 60 mm / min and a force of 0.5 N to 1.5 N.

[0027] The above storage unit further includes a chamber maintained under high temperature and high humidity conditions, and the second container can be stored within the chamber.

[0028] The interior of the chamber can be maintained at a temperature of 40 to 80 degrees Celsius.

[0029] The interior of the chamber can be maintained at a humidity of 70%RH to 99%RH. Effects of the invention

[0030] The battery cell evaluation method and battery cell evaluation device according to an embodiment of the present invention store the pouch film in an electrolyte atmosphere, thereby improving the accuracy regarding whether the outer layer of the pouch film has peeled off.

[0031] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the accompanying drawings. Brief explanation of the drawing

[0032] Figure 1 is a diagram showing the electrolyte injection process during the battery cell manufacturing process. Figure 2 is a diagram showing the degas and resealing processes after the electrolyte injection process of Figure 1. FIG. 3 is a flowchart illustrating a battery cell evaluation method according to one embodiment of the present invention. FIG. 4 is a schematic diagram showing the components of a battery cell evaluation device according to another embodiment of the present invention. Figure 5 is a drawing showing a jig part included in the battery cell evaluation device of Figure 4. Figure 6 (a) is a drawing showing the results of Example 1 according to Experimental Example 1, and (b) is a drawing showing the results of Example 2 according to Experimental Example 1. Figure 7 (a) is a result of Example 1 according to Experimental Example 2, and (b) is a figure showing the result of Example 2 according to Experimental Example 2. Figure 8 (a) is a drawing showing the results for Example 4 according to Experimental Example 3, and (b) is a drawing showing the results for Example 5 according to Experimental Example 3. Specific details for implementing the invention

[0033] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0034] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0035] Furthermore, throughout the specification, when a part is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0037] FIG. 3 is a flowchart illustrating a battery cell evaluation method according to one embodiment of the present invention.

[0038] Referring to FIG. 3, the battery cell evaluation method according to the present embodiment includes a pouch film forming step (S10), a damage providing step (S20), a pouch film storage step (S30), and a peeling detection step (S40).

[0039] The pouch film forming step (S10) may be a step in which a pouch film is formed to form a storage portion in which an electrode assembly is mounted. The pouch film forming step (S10) may form the pouch film to a depth corresponding to the limit forming depth of the pouch film. Here, the pouch film may be formed by direct contact with a mold, such as a punch. However, if multiple types of pouch films need to be compared and evaluated, it is preferable to form all of them to the same depth based on the pouch with the lowest limit forming depth.

[0040] The damage application step (S20) may be a step of applying impact to at least one of the corners of the storage portion formed in the pouch film forming step (S10). More specifically, the damage application step (S20) may be a step of applying impact to the storage portion through the jig portion after mounting a jig portion that is recessed in the same shape as the storage portion. For example, the jig portion may be controlled to apply impact to the storage portion for a time of 0.1 minutes to 1 minute at a speed of 40 mm / min to 60 mm / min and a force of 0.5 N to 1.5 N.

[0041] Accordingly, the battery cell evaluation method according to the present embodiment can simulate a situation in which an impact is applied to the corner of the pouch during the degas process by applying an impact to the storage portion in advance, and the accuracy of the evaluation regarding whether the pouch film peels off during the battery cell manufacturing process can be improved.

[0042] The pouch film storage step (S30) may be a step of storing the pouch film of the damage providing step (S20) inside a second container together with a first container containing an electrolyte.

[0043] Here, the first container is open toward the second container, and the second container may be sealed from the outside air. Additionally, at least a portion of the electrolyte contained in the first container may have evaporated into the second container. Accordingly, the interior of the second container may be diffused with electrolyte vapor generated by the evaporation of the electrolyte contained in the first container. That is, the pouch film contained in the second container may be exposed to the electrolyte vapor.

[0044] Additionally, the pouch film storage step (S30) may further include the step of storing the second container in a chamber maintained under high temperature and high humidity conditions.

[0045] The interior of the chamber may be maintained at a temperature of 40 to 80 degrees Celsius. Specifically, the interior of the chamber may be maintained at a temperature of 50 to 50 degrees Celsius. For example, the interior of the chamber may be maintained at a temperature of 55 to 65 degrees Celsius.

[0046] Accordingly, the interior of the chamber can be maintained at a temperature within the aforementioned range, allowing chemical reactions to occur in the pouch film exposed to the electrolyte vapor, thereby improving the accuracy of the evaluation of whether the pouch film has peeled off. Conversely, if the interior of the chamber is maintained at a temperature below 40 degrees Celsius, it is difficult for chemical reactions to occur between the pouch film and the electrolyte vapor, which makes it difficult to accurately evaluate whether the pouch film has peeled off. Additionally, if the interior of the chamber is maintained at a temperature above 80 degrees Celsius, the temperature is excessively high, causing the electrolyte to evaporate rapidly, which makes it difficult to accurately evaluate whether the pouch film has peeled off.

[0047] The interior of the chamber may be maintained at a humidity of 70%RH to 99%RH. More specifically, the interior of the chamber may be maintained at a humidity of 75%RH to 95%RH. For example, the interior of the chamber may be maintained at a humidity of 80%RH to 90%RH.

[0048] Accordingly, the interior of the chamber can be maintained at a humidity within the aforementioned range, allowing chemical reactions to occur in the pouch film exposed to the electrolyte vapor, thereby improving the accuracy of the evaluation of whether the pouch film has peeled off. Conversely, if the interior of the chamber is maintained at a humidity of less than 70% RHG, it is difficult for chemical reactions to occur between the pouch film and the electrolyte vapor, which makes it difficult to accurately evaluate whether the pouch film has peeled off. Additionally, if the interior of the chamber is maintained at a humidity of more than 99% RH, the amount of water consumed inside the chamber increases, which makes it difficult to proceed with the experiment.

[0049] The second container may be stored in the chamber for 1 to 28 days. More specifically, the second container may be stored in the chamber for 3 to 21 days. For example, the second container may be stored in the chamber for 5 to 16 days.

[0050] Accordingly, the second container can be stored in the chamber for the period described above, allowing sufficient chemical reactions to occur in the pouch film exposed to electrolyte vapor, thereby improving the accuracy of the evaluation of whether the pouch film has peeled off. In contrast, if the second container is stored in the chamber for less than one day, it is difficult for sufficient chemical reactions to occur between the pouch film and the electrolyte vapor, which makes it difficult to accurately evaluate whether the pouch film has peeled off.

[0051] The peeling detection step (S40) may be a step for detecting whether the outer layer of the pouch film stored in the pouch film storage step (S30) has peeled off. Here, the peeling of the outer layer of the pouch film may be detected visually. Here, the peeling of the outer layer may be evaluated based on the corners and edges of the storage portion of the pouch film. For example, the peeling of the outer layer may occur when the outer layer of the pouch film separates or cracks develop, and a space is observed between the aluminum within the pouch film.

[0053] In a battery cell evaluation method according to another embodiment of the present invention, during the pouch film storage step (S30), the first container may contain a solution in which water is mixed with the electrolyte. For example, the first container contains 100 ml of electrolyte and 1000 ppm of H2O -- It may contain a solution in which [it] is mixed.

[0054] Examples of electrolytes used in the present invention include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc., which can be used in the manufacture of lithium secondary batteries, but are not limited to these.

[0055] Specifically, the electrolyte may include an organic solvent and a lithium salt. The organic solvent may be used without special restrictions as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. The lithium salt may be used without special restrictions as long as it is a compound capable of providing lithium ions used in a lithium secondary battery.

[0056] For example, the above electrolyte is LiPF 6-As such, when fluorine is included, it may react with water and oxygen to produce hydrofluoric acid (HF), a corrosive gas. That is, hydrofluoric acid (HF) may be diffused inside the first container along with electrolyte vapor. Accordingly, the battery cell evaluation method according to the present embodiment can determine whether the pouch film has peeled off in a hydrofluoric acid (HF) atmosphere along with an electrolyte atmosphere.

[0057] The second container may be stored in the chamber for 5 to 12 hours. More specifically, the second container may be stored in the chamber for 6 to 11 hours. For example, the second container may be stored in the chamber for 7 to 10 hours.

[0058] Accordingly, the second container can be stored in the chamber for the period described above, allowing sufficient chemical reactions to occur in the pouch film exposed to electrolyte vapor and hydrofluoric acid (HF), thereby improving the accuracy of the evaluation of whether the pouch film has peeled off. Conversely, if the second container is stored in the chamber for less than 5 hours, it is difficult for sufficient chemical reactions to occur between the pouch film and the electrolyte vapor and hydrofluoric acid (HF), which presents a problem in that it is difficult to accurately evaluate whether the pouch film has peeled off.

[0060] FIG. 4 is a schematic diagram showing the components of a battery cell evaluation device according to another embodiment of the present invention.

[0061] Referring to FIG. 4, the battery cell evaluation device (1000) according to the present embodiment may include a pouch molding part (1100), a jig part (1200), a storage part (1300), and a detection part (1400). However, it is not limited thereto, and some of the components may be omitted or other components may be added.

[0062] More specifically, the pouch molding section (1100) can form a storage section in the pouch film. The pouch molding section (1100) can form the storage section to be the same size as or larger than the size of the electrode assembly of the battery cell. In particular, the pouch molding section (1100) can form the storage section such that the maximum molding depth of the pouch film is the same. However, it is not limited thereto, and the pouch molding section (1100) can form a storage section having a maximum molding depth or size suitable for detecting whether the outer layer of the battery cell has peeled off.

[0063] Additionally, the jig portion (1200) can apply impact to at least one of the corners of the storage portion formed in the pouch film in which the electrode assembly is mounted. Further details regarding the jig portion (1200) will be described later together with FIG. 5.

[0064] Additionally, the storage unit (1300) may store the pouch film, which has been impacted from the jig unit (1200), inside a second container along with a first container containing an electrolyte. More specifically, the storage unit (1300) further includes a chamber maintained under high temperature and high humidity conditions, and the second container may be stored inside the chamber. For example, the inside of the chamber may be maintained at a temperature of 40 to 80 degrees Celsius. For another example, the inside of the chamber may be maintained at a humidity of 70%RH to 99%RH.

[0065] Additionally, the detection unit (1400) can determine whether the outer layer of the pouch film has peeled off. More specifically, the detection unit (1400) can determine whether the outer layer of the pouch film has peeled off by visual inspection or by using a detection means such as a microscope. However, the detection unit (1400) is not limited thereto, and any means capable of determining whether the outer layer of the pouch film has peeled off may be included in this embodiment.

[0066] Figure 5 is a drawing showing a jig part included in the battery cell evaluation device of Figure 4.

[0067] Referring to FIGS. 4 and 5, in the battery cell evaluation device (1000) according to the present embodiment, the jig portion (1200) may include a recessed portion (1250) capable of receiving the storage portion formed by the main body portion (1210) and the pouch molding portion (1100). Here, the recessed portion (1250) may be recessed toward the bottom surface with respect to the outer surface of the main body portion (1210).

[0068] The recessed portion (1250) may have a size equal to or larger than the storage portion. More specifically, the recessed portion (1250) may have a size that is 2 mm or more to 6 mm or less larger than the storage portion. For example, the recessed portion (1250) may have a size that is 3 mm or more to 5 mm or less larger than the storage portion. However, it is not limited thereto, and if the recessed portion (1250) of the jig portion (1200) is large enough to apply impact to the storage portion, it may be included in the present embodiment.

[0069] Accordingly, in the battery cell evaluation device (1000) of the present embodiment, the indentation (1250) can apply uniform damage to each corner of the storage portion.

[0070] Additionally, referring to FIG. 5, in the battery cell evaluation device (1000) according to the present embodiment, the jig portion (1200) may further include a notch portion (1250H) formed in the recessed portion (1250). More specifically, in the jig portion (1200), the notch portion (1250H) may be formed at each corner of the recessed portion (1250). For example, the notch portion (1250H) may be formed in a circular shape. However, the shape of the notch portion (1250H) is not limited thereto, and may be included in the present embodiment as long as the shape of each corner of the recessed portion (1250) does not cause damage to the storage portion.

[0071] Accordingly, in the battery cell evaluation device (1000) of the present embodiment, during the process of mounting the storage unit to the recessed portion (1250) of the jig portion (1200), damage to each corner of the storage unit caused by the user's handling of the recessed portion (1250) can be prevented.

[0072] Additionally, the jig part (1200) can apply impact to the storage part for a time of 0.1 minutes to 1 minute with a speed of 40 mm / min to 60 mm / min and a force of 0.5 N to 1.5 N.

[0073] Accordingly, in the battery cell evaluation device (1000) according to the present embodiment, the jig part (1200) can simulate a situation in which an impact is applied to the corner of the storage part during the degas process by applying an impact to the storage part in advance, and the accuracy of the evaluation of whether the pouch film is peeled off, performed by the detection part (1400), can be improved.

[0074] The content of the present invention is explained below through more specific embodiments, but the following embodiments are intended to illustrate the invention and the scope of the invention is not limited thereto.

[0076] <Example 1>

[0077] Regarding the pouch film of manufacturer DNP, a pouch film with a storage portion formed using an N93 forming tool was manufactured. After mounting a jig portion that is recessed identical to the shape of the storage portion of the manufactured pouch film onto the storage portion, an impact was applied to the corner of the storage portion through the jig portion. At this time, the jig portion applied an impact to the corner of the storage portion for 0.5 minutes at a speed of 50 mm / min and a force of 0.5 N to 1.5 N.

[0079] <Example 2>

[0080] In Example 1 above, the pouch film is a pouch film from the manufacturer SHOWA. Except for this, a pouch film with a storage portion formed in the same way as in Example 1 was manufactured, and an impact was applied to the corner of the storage portion.

[0082] <Example 3>

[0083] In Example 1 above, the pouch film was formed with a forming depth of 4.5 mm for the storage portion. Except for this, a pouch film with a storage portion formed in the same way as in Example 1 was manufactured, and an impact was applied to the corner of the storage portion.

[0085] <Example 4>

[0086] In Example 1 above, the pouch film was formed with a forming depth of 5.0 mm for the storage portion. Except for this, a pouch film with a storage portion formed in the same way as in Example 1 was manufactured, and an impact was applied to the corner of the storage portion.

[0088] <Example 5>

[0089] In the above Example 1, the pouch film was a pouch film manufactured by SHOWA, and the pouch film was formed with a forming depth of 5.0 mm. Except for this, a pouch film with a formed storage portion was manufactured in the same manner as in Example 1, and an impact was applied to the corner of the storage portion.

[0091] <Example 6>

[0092] In the above Example 1, the pouch film was a pouch film manufactured by SHOWA, and the pouch film was formed with a forming depth of 5.5 mm. Except for this, a pouch film with a formed storage portion was manufactured in the same manner as in Example 1, and an impact was applied to the corner of the storage portion.

[0094] <Experimental Example 1_High Temperature and High Humidity Conditions>

[0095] Five pouch films prepared in Example 1 and five pouch films prepared in Example 2 were stored in a chamber maintained at 60 degrees and 90% RH, respectively, and then the outer layer of each pouch film was determined, and the results are shown in Table 1.

[0096] Sample Example 1 Example 2 1 day 3 days 7 days 1 day 3 days 7 days 1 O O O O O O 2 O O O O O O 3 O O O O O O 4 O O O O O O 5 O O O O O O

[0097] Referring to Figure 6 and Table 1, it can be seen that when a pouch film is stored under high temperature and high humidity conditions, no separate outer layer delamination phenomenon is detected even after some time has passed. Accordingly, it can be seen that when a pouch film is stored under simple high temperature and high humidity conditions as in Experimental Example 1, it is difficult to detect in advance a pouch film in which outer layer delamination may occur during the battery cell manufacturing process.

[0099] <Experimental Example 2_Electrolyte Atmosphere>

[0100] Standard electrolyte (EC : EMC : DMC = 3:3:4, LiPF6 1M, density 1.227 g / ml) Along with the first container containing this, five pouch films prepared in Example 1 and five pouch films prepared in Example 2 were placed in the second container, and the second container was stored in a sealed state in a chamber maintained at 60 degrees and 90% RH, respectively. Subsequently, the outer layer of each pouch film was determined, and the results are shown in Table 2.

[0101] Sample Example 1 Example 2 1 day 7 days 14 days 1 day 7 days 14 days 1 O NG NG O O NG 2 O NG NG O O O 3 O O NG O O O

[0102] Referring to Figure 7 and Table 2, it can be seen that when a pouch film is stored in an electrolyte atmosphere along with high temperature and high humidity conditions, delamination of the outer layer is detected at the corners of some pouch films after 7 and / or 14 days. Accordingly, unlike Experimental Example 1, when a pouch film is stored in an electrolyte atmosphere along with simple high temperature and high humidity conditions, it can be confirmed that delamination of the outer layer that may occur during the battery cell manufacturing process can be detected in advance, even when the pouch film is from a different manufacturer as in Examples 1 and 2.

[0103] In addition, in the case of Example 1, it can be seen that outer layer delamination is detected in some samples from day 7, whereas in the case of Example 2, it can be seen that outer layer delamination is detected in some samples from day 14. Accordingly, in the case of Example 1, it can be seen that outer layer delamination is detected rapidly in an electrolyte atmosphere. Accordingly, regarding pouch films from different manufacturers as in Example 1 and Example 2, it is possible to determine which manufacturer's pouch film is relatively prone to outer layer delamination during the battery cell manufacturing process.

[0105] <Experimental Example 3_Electrolyte and Hydrofluoric Acid (HF) Atmosphere>

[0106] Five pouch films prepared in Examples 3 to 6 were placed in a second container along with a first container containing 100 ml of standard electrolyte (EC : EMC : DMC = 3:3:4, LiPF6 1M, density 1.227 g / ml) and 1000 ppm of H2O. The second container was then sealed and stored in a chamber maintained at 60°C and 90% RH, respectively. Subsequently, the outer layer of each pouch film was determined, and the results are shown in Table 3.

[0107] Pouch film Forming Depth (mm) 2 hours 4 hours 8 hours Example 3 Manufacturer DNP 4.5 O / 5 0 / 5 5 / 5 Example 4 Manufacturer DNP 5.0 O / 5 0 / 5 5 / 5 Example 5 Manufacturer: SHOWA 5.0 O / 5 0 / 5 5 / 5 Example 6 Manufacturer: SHOWA 5.5 O / 5 O / 5 5 / 5

[0108] Referring to Figure 8 and Table 3, when the pouch film is stored in an atmosphere of electrolyte and hydrofluoric acid (HF) along with high temperature and high humidity conditions, it can be confirmed that outer layer delamination is detected in some corner portions of the pouch films of Examples 4 and 5, which have the same depth of formation of the storage portion, after 8 hours have elapsed. Accordingly, unlike Experimental Example 1, when the pouch film is stored in an atmosphere of electrolyte and hydrofluoric acid (HF) along with simple high temperature and high humidity conditions, it can be confirmed that the presence of outer layer delamination, which may occur during the battery cell manufacturing process, can be quickly detected even when the pouch films are from different manufacturers, such as Examples 4 and 5.

[0109] In addition, unlike Experimental Example 2, where outer layer delamination was detected after 7 days or more, it can be confirmed that when the pouch film is stored in a hydrofluoric acid (HF) atmosphere along with an electrolyte atmosphere, the pouch film in which outer layer delamination may occur during the battery cell manufacturing process can be detected more quickly.

[0110] In addition, when comparing Example 3 and Example 6, outer layer delamination was detected in the pouch film of Example 3 after 8 hours at a relatively small formation depth (4.5 mm), and outer layer delamination was detected in the pouch film of Example 6 after the same amount of time at a relatively large formation depth (5.5 mm). Accordingly, it can be confirmed that outer layer delamination is well detected even for pouch films with different manufacturers and formation depths, such as Example 3 and Example 6, under high temperature and high humidity conditions along with an electrolyte and hydrofluoric acid (HF) atmosphere.

[0111] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

Claim 1 A battery cell evaluation method comprising: a step of forming a pouch film to form a storage portion in which an electrode assembly is mounted; a step of applying an impact to at least one of the corners of the storage portion; a step of storing the pouch film inside a second container together with a first container containing an electrolyte; and a step of detecting whether the outer layer of the pouch film has peeled off. Claim 2 A battery cell evaluation method according to claim 1, wherein the first container is open toward the second container and the second container is sealed from external air. Claim 3 A battery cell evaluation method according to paragraph 2, wherein at least a portion of the electrolyte is evaporated inside the second container. Claim 4 A battery cell evaluation method according to claim 2, further comprising the step of storing the second container in a chamber maintained under high temperature and high humidity conditions. Claim 5 A battery cell evaluation method according to claim 4, wherein the inside of the chamber is maintained at a temperature of 40 to 80 degrees Celsius. Claim 6 A battery cell evaluation method according to claim 4, wherein the interior of the chamber is maintained at a humidity of 70%RH to 99%RH. Claim 7 In paragraph 4, the battery cell evaluation method wherein the second container is stored in the chamber for 1 to 28 days. Claim 8 In claim 1, the first container is a battery cell evaluation method containing a solution in which water is mixed with the electrolyte. Claim 9 In claim 8, the battery cell evaluation method wherein the second container is stored for 5 to 12 hours in a chamber maintained under high temperature and high humidity conditions. Claim 10 A battery cell evaluation method according to claim 1, wherein the step of applying impact to the storage portion further includes the step of mounting a jig portion that is recessed identical to the shape of the storage portion onto the storage portion, and applying impact to the storage portion through the jig portion. Claim 11 A battery cell evaluation method according to claim 10, wherein the jig part applies impact to the storage part for a time of 0.1 minutes to 1 minute at a speed of 40 mm / min to 60 mm / min and a force of 0.5 N to 1.5 N. Claim 12 A battery cell evaluation device comprising: a jig portion for applying impact to at least one of the corners of a pouch film in which an electrode assembly is mounted and a storage portion is formed; a storage portion for storing the pouch film, which has been impacted from the jig portion, inside a second container together with a first container containing an electrolyte; and a detection portion for determining whether the outer layer of the pouch film has peeled off. Claim 13 In claim 12, the above jig portion includes a main body portion and a recessed portion capable of accommodating the above storage portion, and the recessed portion is recessed toward the bottom surface relative to the outer surface of the main body portion, in a battery cell evaluation device. Claim 14 In Clause 13, the above-mentioned recess has a size equal to or larger than the above-mentioned storage portion in a battery cell evaluation device. Claim 15 In Clause 13, a battery cell evaluation device having notches formed at each corner of the above-mentioned recess. Claim 16 In paragraph 15, the battery cell evaluation device in which the notch portion is formed in a circular shape. Claim 17 In claim 12, the battery cell evaluation device wherein the jig part applies impact to the storage part for a time of 0.1 minutes to 1 minute at a speed of 40 mm / min to 60 mm / min and a force of 0.5 N to 1.5 N. Claim 18 In paragraph 12, the storage unit further comprises a chamber maintained under high temperature and high humidity conditions, and the second container is a battery cell evaluation device stored within the chamber. Claim 19 In claim 18, a battery cell evaluation device in which the interior of the chamber is maintained at a temperature of 40 to 80 degrees Celsius. Claim 20 In claim 18, a battery cell evaluation device in which the interior of the chamber is maintained at a humidity of 70%RH to 99%RH.

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