Secondary battery for internal short-circuit experiments, method for manufacturing the same, and experimental method.

Abstract

The present invention relates to a secondary battery for internal short circuit experiments, comprising: an electrode assembly; and a pouch accommodating the electrode assembly. The electrode assembly comprises: a first main electrode comprising a first main current collector and a first main coating layer coated on the remaining surface of the first main current collector except for a first plain surface defined by the first main current collector; a second electrode comprising a second coating layer coated on the surface of the second current collector; a main separator disposed between the first main electrode and the second electrode and having through holes formed at positions corresponding to the first plain surface; an auxiliary separator detachably attached to the main separator and closing or opening the through holes; and a first auxiliary electrode detachably attached to the first plain surface and connecting the first plain surface of the first main current collector to the second electrode via the through holes that are opened when removed so as to cause an internal short circuit.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0033530 filed on March 14, 2023, and all the contents disclosed in the documents of the Korean Patent Application are incorporated herein by reference.

[0002] The present invention relates to a secondary battery for internal short-circuit experiments capable of experimenting with an internal short circuit between a positive electrode, a lithium deposit, and a negative electrode, or an internal short circuit between a current collector provided on the positive electrode and the negative electrode, a method for manufacturing the same, and an experimental method.

Background Art

[0003] Generally, a secondary battery refers to a battery that can be charged and discharged, unlike a primary battery that cannot be charged. Such secondary batteries are widely used in mobile phones, notebook computers, video cameras, electric vehicles, and the like.

[0004] The secondary battery is classified into a can-type secondary battery in which an electrode assembly is built in a metal can and a pouch-type secondary battery in which an electrode assembly is built in a pouch. The can-type secondary battery has a structure including an electrode assembly, an electrolyte, a can for accommodating the electrode assembly and the electrolyte, and a cap assembly mounted on an opening of the can. The pouch-type secondary battery has a structure including an electrode assembly, an electrolyte, and a pouch for accommodating the electrode assembly and the electrolyte.

[0005] Here, an internal short-circuit experiment is performed on the secondary battery to enhance safety. That is, the internal short circuit of the secondary battery can be roughly divided into two types. First, it is an internal short circuit between the positive electrode and the negative electrode, and second, it is an internal short circuit between the positive electrode, a lithium deposit, and the negative electrode.

[0006] The first internal short circuit is more dangerous than the second internal short circuit because the potential difference between the contact materials is larger. Furthermore, in the second internal short circuit, if the positive electrode current collector is short-circuited with the charged negative electrode, and the positive electrode coating layer is not present in the position facing the negative electrode, the negative electrode will not be fully charged, making it difficult to conduct the experiment smoothly. Also, in the second internal short circuit, if the positive electrode current collector is short-circuited with lithium deposits generated on the charged negative electrode, and the positive electrode coating layer is not present in the position facing the negative electrode, the lithium deposits will not be generated over the desired area but only partially, making it difficult to conduct the experiment in the desired direction. Therefore, in order to experiment with internal short circuits in a secondary battery in a desired direction, a secondary battery specifically designed for internal short-circuit experiments is required. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a secondary battery for internal short-circuit experiments, a method for manufacturing the same, and a method for conducting experiments that can smoothly and accurately test for internal short circuits between the positive electrode, lithium precipitate, and negative electrode, or between the current collector contained in the positive electrode and the negative electrode. [Means for solving the problem]

[0008] The secondary battery for internal short-circuit experiments of the present invention includes an electrode assembly and a pouch for housing the electrode assembly, the electrode assembly comprising: a main first current collector and a main first electrode composed of a main first coating layer coated on the remaining surface excluding a first blank surface partitioned by the main first current collector; a second current collector and a second electrode composed of a second coating layer coated on the surface of the second current collector; a main separator disposed between the main first electrode and the second electrode and having a through hole formed at a position corresponding to the first blank surface; an auxiliary separator detachably attached to the main separator and closing or opening the through hole; and an auxiliary first electrode detachably attached to the first blank surface and connecting the first blank surface of the main first current collector and the second electrode via the through hole, which is opened when removed, to cause an internal short circuit. This allows experimentation of an internal short circuit between the main first electrode and the second electrode in a desired direction.

[0009] The auxiliary first electrode may include an auxiliary first current collector having an attachment surface formed thereon that is detachably attached to the first blank surface, and an auxiliary first coating layer coated on the attachment surface. This allows the auxiliary first electrode to be stably and detachably attached to the first blank surface.

[0010] The first blank surface can be formed on the edge of the main first current collector. This allows the auxiliary first electrode to be easily attached to or removed from the first blank surface without damaging the main first coating layer.

[0011] The auxiliary first current collector is located outside the main first electrode when its attachment surface adheres to the first blank surface, and may further include a second blank surface for separating the auxiliary first current collector from the first blank surface. This allows for easy removal of the auxiliary first electrode adhering to the first blank surface.

[0012] The auxiliary separator may include a separating surface that is detachably attached to the main separator while covering the through hole, and a gripping surface that is located outside the main separator when the separating surface is attached to the main separator, for separating the auxiliary separator from the main separator. This allows for easy removal of the auxiliary separator attached to the main separator.

[0013] The auxiliary first electrode may have the same thickness as the main first coating layer. This prevents a step from occurring between the auxiliary first electrode and the main first coating layer.

[0014] The second coating layer includes a first coating surface coated on the surface of the second current collector corresponding to the through hole, and a second coating surface coated on the surface of the second current collector that is not coated by the first coating surface, wherein the first coating surface may have a smaller thickness than the second coating surface. This allows lithium deposits to be smoothly generated on the first coating surface during charging and discharging, and as a result, internal short circuits between the main first electrode, lithium deposits, and the second electrode can be experimented with.

[0015] The main first electrode and the auxiliary first electrode can have the same polarity. The main first electrode and the auxiliary first electrode may be positive electrodes. The second electrode may also be a negative electrode.

[0016] The auxiliary first electrode can be detachably attached to the first blank surface via adhesive tape. This allows the auxiliary first electrode to be stably and detachably attached to the first blank surface.

[0017] The auxiliary separator and the main separator can be detachably attached by heat fusion. This allows the main separator and the auxiliary separator to be stably attached, and the adhesive force between the main separator and the auxiliary separator weakens due to impregnation with the electrolyte, allowing the main separator and the auxiliary separator to be easily separated.

[0018] The present invention provides a method for manufacturing a secondary battery for internal short-circuit experiments, which may include: (a) preparing a main first current collector with a partitioned first blank surface, coating the surface of the main first current collector with a main first coating layer, and then removing the main first coating layer coated on the first blank surface to manufacture a main first electrode; (b) coating the surface of a second current collector with a second coating layer to manufacture a second electrode; (c) cutting a portion of the surface corresponding to the first blank surface to form a through-hole when placed between the main first electrode and the second electrode to manufacture a main separator; (d) manufacturing an auxiliary separator that closes or opens the through-hole, and then detachably attaching the auxiliary separator to the main separator while covering the through-hole; and (e) manufacturing an auxiliary first electrode that connects or disconnects the main first current collector and the second electrode via the through-hole to cause an internal short circuit, and then detachably attaching the auxiliary first electrode to the first blank surface. This method allows for the easy manufacture of secondary batteries for internal short-circuit testing of finished products.

[0019] In step (e) above, the auxiliary first electrode may consist of an auxiliary first current collector having an attachment surface that is detachably attached to the first bare surface, and an auxiliary first coating layer that is coated on the outer surface of the attachment surface.

[0020] In step (a), the first blank surface is defined at the edge of the main first current collector, and in step (e), the auxiliary first current collector is located outside the main first electrode when the attachment surface is attached to the first blank surface and may include a second blank surface for separating the auxiliary first current collector from the first blank surface.

[0021] Step (b) further includes cutting the surface of the second coating layer corresponding to the through hole when the main separator is positioned between the main first electrode and the second electrode after the second coating layer has been coated, wherein the second coating layer includes a cut first coating surface and an uncut second coating surface, and the first coating surface may have a smaller thickness than the second coating surface.

[0022] The process may further include the steps of: (f) after step (e) above, (g) placing the main separator, to which the auxiliary separator is attached, between the main first electrode, to which the auxiliary first electrode is attached, and the second electrode to manufacture an electrode assembly; and (g) housing the electrode assembly in a pouch and then sealing the pouch to manufacture the secondary battery for internal short-circuit experiments. The main first electrode and the auxiliary first electrode can have the same polarity.

[0023] The experimental method of the secondary battery for internal short-circuit experiment of the present invention includes: (A) a step of applying a voltage to the secondary battery for internal short-circuit experiment according to any one of claims 1 to 12 and performing charge and discharge; (B) a step of cutting open the pouch of the secondary battery for internal short-circuit experiment; (C) a step of removing the auxiliary first electrode attached to the main first electrode of the electrode assembly through the cut portion of the pouch; (D) a step of removing the auxiliary separator attached to the main separator of the electrode assembly through the cut portion of the pouch and opening the through-hole of the main separator; (E) a step of pressing the secondary battery for internal short-circuit experiment and causing an internal short circuit by bringing the first unground surface of the main first current collector into contact with the second electrode through the through-hole. Thereby, the internal short circuit between the main first electrode and the second electrode can be experimentally performed in a desired direction.

[0024] In the step (A), the second coating layer of the second electrode is composed of a first coating surface and a second coating surface having a thickness larger than that of the first coating surface, and lithium deposits can be generated on the first coating surface corresponding to the auxiliary first electrode during charge and discharge. Thereby, the internal short circuit among the main first electrode, the lithium deposits, and the second electrode can be experimentally performed in a desired direction.

Effects of the Invention

[0025] The secondary battery for internal short-circuit experiment of the present invention can experimentally perform a short circuit between the main first electrode and the second electrode or a short circuit between the current collector included in the main first electrode and the second electrode in a desired direction.

Brief Description of the Drawings

[0026] [Figure 1] It is a perspective view showing an assembled state of the secondary battery for internal short-circuit experiment according to the first embodiment of the present invention. [Figure 2] It is a separated perspective view showing the electrode assembly of FIG. 1. [Figure 3] It is a sectional view taken along line A-A shown in FIG. 2. [Figure 4] This is a cross-sectional view along line BB shown in Figure 2. [Figure 5] Figure 2 shows a cross-sectional view along the CC line. [Figure 6] Figure 1 is a cross-sectional view showing the electrode assembly. [Figure 7] Figure 6 is a cross-sectional view showing the electrode assembly with the auxiliary first electrode and auxiliary separator removed. [Figure 8] Figure 7 is a cross-sectional view showing the electrode assembly in a crimped state. [Figure 9] This is a flowchart illustrating a method for manufacturing a secondary battery for internal short-circuit testing according to the first embodiment of the present invention. [Figure 10] (a) A perspective view showing the steps for manufacturing the main first electrode. [Figure 11] (b) A perspective view showing the steps for manufacturing the second electrode. [Figure 12] (c) A perspective view showing the steps for manufacturing the main separator. [Figure 13] (d) A perspective view showing the step of attaching the auxiliary separator to the main separator. [Figure 14] (e) This is a perspective view showing the step of attaching the auxiliary first electrode to the main first electrode. [Figure 15] This is a flowchart illustrating the experimental method for a secondary battery for internal short-circuit testing according to the first embodiment of the present invention. [Figure 16] This is a plan view showing the charging and discharging steps. [Figure 17] This is a plan view showing the steps for cutting the pouch. [Figure 18] This is a cross-sectional view showing the step of removing the auxiliary separator and the auxiliary first electrode. [Figure 19] This is a cross-sectional view showing the crimping step of a secondary battery used for internal short-circuit testing. [Figure 20] This is a separated perspective view showing an electrode assembly according to a second embodiment of the present invention. [Figure 21] Figure 20 is a cross-sectional view showing the electrode assembly. [Figure 22] This is a cross-sectional view of the electrode assembly from Figure 21, showing the electrode assembly with the auxiliary first electrode and auxiliary separator removed. [Figure 23] Figure 22 is a cross-sectional view showing the electrode assembly in a crimped state. [Modes for carrying out the invention]

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those with ordinary skill in the art to which the present invention pertains can easily implement it. However, the present invention may be realized in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly illustrate the present invention, parts unrelated to the description have been omitted from the drawings, and similar parts throughout the specification have been denoted by similar reference numerals.

[0028] [Secondary battery for internal short-circuit experiment according to the first embodiment of the present invention] Figure 1 is a perspective view showing the assembled state of a secondary battery for internal short-circuit experiments according to the first embodiment of the present invention; Figure 2 is a separated perspective view showing the electrode assembly of Figure 1; Figure 3 is a cross-sectional view along line AA shown in Figure 2; Figure 4 is a cross-sectional view along line BB shown in Figure 2; Figure 5 is a cross-sectional view along line CC shown in Figure 2; Figure 6 is a cross-sectional view showing the electrode assembly of Figure 1; Figure 7 is a cross-sectional view showing the electrode assembly with the auxiliary first electrode and auxiliary separator removed from Figure 6; and Figure 8 is a cross-sectional view showing the electrode assembly in a crimped state from Figure 7.

[0029] The secondary battery for internal short-circuit experiments according to the first embodiment of the present invention is for experimenting with internal short circuits between the positive electrode, lithium precipitate (Li), and negative electrode. In other words, the secondary battery 1 for internal short-circuit experiments according to the first embodiment of the present invention includes, as shown in Figure 1, an electrode assembly 10, a pouch 20 that houses the electrode assembly 10, and an electrode lead 30 that is connected to the electrode assembly 10 and whose tip is drawn out of the pouch 20.

[0030] electrode assembly As shown in Figure 2, the electrode assembly 10 includes a main first electrode 11, a second electrode 12, a main separator 13, an auxiliary separator 14, and an auxiliary first electrode 15. Here, the auxiliary separator 14 is attached to the main separator 13, and the auxiliary first electrode 15 is attached to the main first electrode 11.

[0031] On the other hand, the main first electrode 11 is the positive electrode, and the second electrode 12 is the negative electrode. The auxiliary first electrode 15 has the same polarity as the main first electrode 11. That is, the auxiliary first electrode 15 is the positive electrode.

[0032] As shown in Figure 3, the main first electrode 11 includes a main first current collector 111 and a main first coating layer 112 that is coated on the remaining surface of the main first current collector 111, excluding the first blank surface 1111 that is partitioned off. That is, the main first electrode 11 consists of a main first coating layer 112 coated with the first electrode active material and a first blank surface 1111 where the first electrode active material is absent. The main first current collector 111 has electrode tabs formed thereon that are connected to the electrode leads 30.

[0033] On the other hand, the manufacturing method for the main first electrode 11 involves coating both surfaces of the main first current collector 111 with a main first coating layer 112. Next, the main first coating layer 112 coated on the first blank surface 1111 partitioned on one side of the main first current collector 111 is removed. This allows the main first electrode 11, consisting of the first blank surface 1111 and the main first coating layer 112, to be manufactured.

[0034] On the other hand, the main first electrode 11 may be the positive electrode. In this case, the main first coating layer 112 may be a positive electrode coating layer made of a positive electrode active material.

[0035] On the other hand, the main first current collector 111 can be provided as a metal plate. Preferably, the main first current collector 111 can be made of aluminum (Al) material.

[0036] On the other hand, the first blank surface 1111 can be formed on any portion of the edge of the main first current collector 111, as shown in Figure 2. Preferably, the first blank surface 1111 can be formed on the edge surface of the main first current collector 111 where there are no electrode tabs. This allows the auxiliary first electrode 15 to be attached to or removed from the first blank surface 1111 without damaging the main first coating layer 112.

[0037] As shown in Figure 5, the second electrode 12 includes a second current collector 121 and a second coating layer 122 coated on the surface of the second current collector 121. That is, the second electrode 12 is manufactured by coating the surface of the second current collector 121 with the second coating layer 122. The second current collector 121 has an electrode tab formed thereon for connecting to the electrode lead 30.

[0038] On the other hand, the second electrode 12 may be the negative electrode. The second current collector 121 is provided as a metal plate, and preferably the second current collector 121 is made of copper.

[0039] On the other hand, the second electrode 12 has a structure that allows lithium precipitates (Li) to be generated in the portion of the surface of the second coating layer 122 during charging and discharging. In other words, the second coating layer 122 includes a first coating surface 1221 that is coated on the surface of the second current collector 121 corresponding to the through hole 131 of the main separator 13, and a second coating surface 1222 that is coated on the surface of the second current collector 121 that is not coated on the first coating surface 1221. Here, the first coating surface 1221 has a smaller thickness than the second coating surface 1222. As a result, lithium precipitates (Li) are generated on the surface of the second coating layer 122 during the charging and discharging process, and in this case, lithium precipitates are generated in large quantities on the first coating surface 1221 where the interaction between the main first coating layer 112 and the first coating surface 1221 of the second coating layer 122 does not occur smoothly, and dendrites grow.

[0040] On the other hand, the thickness of the first coating surface 1221 can be formed such that the NP ratio (ratio) of the thickness of the second coating surface 1222 is 100 or less. That is, the thickness of the first coating surface 1221 can be formed to 5-80% of the thickness of the second coating surface 1222, preferably to 40-75% of the thickness of the second coating surface 1222. In particular, the first coating surface 1221 can be formed by cutting a portion of the surface of the second coating surface 1222.

[0041] As shown in Figure 2, the main separator 13 is intended to prevent the main first electrode 11 and the second electrode 12 from coming into contact. In other words, the main separator 13 is placed between the main first electrode 11 and the second electrode 12.

[0042] In particular, the main separator 13 has a through hole 131 formed at a position corresponding to the first blank surface 1111, and the first blank surface 1111 and the second electrode 12 come into contact through the through hole 131, causing an internal short circuit. On the other hand, the through hole 131 is formed at a set distance inward from the edge of the main separator 13 in order to reinforce the strength of the main separator 13.

[0043] Referring to Figure 4, the auxiliary separator 14 is for closing the through hole 131 formed in the main separator 13. That is, the auxiliary separator 14 is large enough to cover the through hole 131 and is detachably attached to the main separator 13 while covering the through hole 131. As a result, the auxiliary separator 14 can close or open the through hole 131.

[0044] Here, the adhesive force between the main separator 13 and the auxiliary separator 14 is weaker than the adhesive force between the main separator 13 and the first electrode. This prevents the main separator 13 from separating from the first electrode when the auxiliary separator 14 is removed from the main separator 13.

[0045] On the other hand, the auxiliary separator 14 can be made of the same material as the main separator 13. However, the auxiliary separator 14 has a thinner thickness than the main separator 13. This is because, as shown in Figure 2, the auxiliary separator 14 is placed on the upper surface of the main separator 13, which can create a step between the main separator 13 and the main first electrode 11. By minimizing the thickness of the auxiliary separator 14, the step between the main separator 13 and the main first electrode 11 can be minimized.

[0046] On the other hand, the auxiliary separator 14 has a structure that allows it to be easily removed from the main separator 13. That is, the auxiliary separator 14 includes a separation surface 141 that is detachably attached to the main separator 13 while covering the through hole 131, and a gripping surface 142 that is located outside the main separator 13 when the separation surface 141 is attached to the main separator 13, for separating the auxiliary separator 14 from the main separator 13. As a result, by pulling the gripping surface 142 that is exposed outside the main separator 13, the separation surface 141 attached to the main separator 13 can be easily removed.

[0047] On the other hand, the length of the gripping surface exposed to the outside of the main separator 13 can be formed to be 5 mm to 50 mm, preferably 10 to 20 mm. The auxiliary separator 14 and the main separator 13 can be bonded together by thermal fusion. That is, the auxiliary separator 14 and the main separator 13 can be bonded together using heat and pressure. When impregnated with electrolyte, the bonding force between the auxiliary separator 14 and the main separator 13 weakens, allowing them to be easily separated.

[0048] On the other hand, in another embodiment, the auxiliary separator 14 can be detachably attached to the main separator 13 via an adhesive. This allows for the maintenance of a stable adhesive force between the auxiliary separator 14 and the main separator 13.

[0049] The auxiliary first electrode 15 is intended to fill the surface of the second electrode 12 facing the first blank surface 1111 in order to experiment with an internal short circuit between the first blank surface 1111 and the second electrode 12.

[0050] In other words, the auxiliary first electrode 15 is detachably attached to the first blank surface 1111 and has a structure that connects the first blank surface 1111 of the main first current collector 111 and the second electrode 12 via a through hole 131 that is opened when removed, causing an internal short circuit.

[0051] As an example, the auxiliary first electrode 15 includes an auxiliary first current collector 151 having an attachment surface 1511 that is detachably attached to the first plain surface 1111, and an auxiliary first coating layer 152 that is coated on the attachment surface 1511.

[0052] Here, the adhesion surface 1511 has the same area as the first plain surface 1111. This prevents the formation of gaps between the adhesion surface 1511 and the first coating layer. On the other hand, the adhesion surface 1511 may be formed to be 1 to 2 mm larger per unit area than the first plain surface 1111, which significantly prevents the formation of gaps between the adhesion surface 1511 and the first coating layer.

[0053] On the other hand, the auxiliary first electrode 15 can have the same polarity as the main first electrode 11. That is, the auxiliary first electrode 15 can be formed as a positive electrode, and as a result, the auxiliary first coating layer 152 may be a positive electrode coating layer made of a positive electrode active material.

[0054] On the other hand, the adhesive force between the auxiliary first electrode 15 and the first blank surface 1111 is smaller than the adhesive force between the main first electrode 11 and the main separator 13. This prevents the main first electrode 11 and the main separator 13 from separating when the auxiliary first electrode 15 is removed from the first blank surface 1111.

[0055] On the other hand, the auxiliary first electrode 15 can be detachably attached to the first blank surface 1111 via adhesive tape. This allows for stable adhesion between the auxiliary first electrode 15 and the first blank surface 1111, and when impregnated with electrolyte, the adhesive strength of the adhesive tape weakens, allowing for easy separation between the auxiliary first electrode 15 and the first blank surface 1111.

[0056] On the other hand, in another embodiment, the auxiliary first electrode 15 can be detachably attached to the first plain surface 1111 via an adhesive, thereby maintaining a stable adhesive force between the auxiliary first electrode 15 and the first plain surface 1111. Furthermore, the auxiliary first electrode and the first blank surface may adhere to each other by heat and pressure.

[0057] On the other hand, the auxiliary first current collector 151 may further include a second blank surface 1512 that is located outside the main first electrode 11 when the adhesion surface 1511 adheres to the first blank surface 1111, and separates the auxiliary first current collector 151 from the first blank surface 1111. That is, the second blank surface 1512 is formed as a surface that is not coated with the auxiliary first coating layer 152. This allows the auxiliary first electrode 15 to be easily removed from the first blank surface 1111 using the second blank surface 1512.

[0058] On the other hand, the auxiliary first electrode 15 can have the same thickness as the first coating layer. This prevents a step from occurring between the auxiliary first electrode 15 and the main first electrode 11.

[0059] An electrode assembly 10 having such a structure has a main first electrode 11 and a second electrode 12, each with an auxiliary first electrode 15 attached, arranged alternately with a main separator 13 to which an auxiliary separator 14 is attached interposed. Here, when the electrode assembly 10 removes the auxiliary separator 14 attached to the main separator 13 and the auxiliary first electrode 15 attached to the main first electrode 11, the first blank surface 1111 of the main first electrode 11 and the lithium deposits formed on the second electrode 12 during charging and discharging can be brought into contact with the second electrode 12, thereby causing an internal short circuit between the main first electrode 11, the lithium deposits, and the second electrode 12.

[0060] Pouch The pouch 20 is for containing the electrode assembly 10 and the electrolyte. Specifically, the pouch 20 includes an upper pouch and a lower pouch for containing the electrode assembly 10 and the electrolyte.

[0061] Electrode lead The electrode lead 30 is connected to the electrode tabs formed on the main first electrode 11 and the second electrode 12 of the electrode assembly 10, respectively, and has a structure in which its tip is pulled out of the pouch 20. Specifically, the electrode lead 30 includes a first electrode lead 31 connected to the electrode tab of the main first electrode 11, and a second electrode lead 32 connected to the electrode tab of the second electrode 12.

[0062] Therefore, the secondary battery 1 for internal short-circuit experiments according to the first embodiment of the present invention can be used to experiment on internal short circuits between the main first electrode 11, lithium precipitate, and the second electrode 12. The following describes a method for manufacturing a secondary battery for internal short-circuit experiments according to the first embodiment of the present invention.

[0063] [Manufacturing method for a secondary battery for internal short-circuit testing according to the first embodiment of the present invention] Figure 9 is a flowchart showing a method for manufacturing a secondary battery for internal short-circuit experiments according to the first embodiment of the present invention; Figure 10 is a perspective view showing the step of manufacturing the main first electrode (a); Figure 11 is a perspective view showing the step of manufacturing the second electrode 12 (b); Figure 12 is a perspective view showing the step of manufacturing the main separator (c); Figure 13 is a perspective view showing the step of attaching the auxiliary separator to the main separator (d); and Figure 14 is a perspective view showing the step of attaching the auxiliary first electrode to the main first electrode (e).

[0064] A method for manufacturing a secondary battery for internal short-circuit experiments according to the first embodiment of the present invention, as shown in Figure 9, includes: (a) the step of manufacturing a main first electrode 11; (b) the step of manufacturing a second electrode; (c) the step of manufacturing a main separator; (d) the step of manufacturing an auxiliary separator and attaching it to the main separator; (e) the step of manufacturing an auxiliary first electrode and attaching it to the main first electrode 11; (f) the step of manufacturing an electrode assembly; and (g) the step of manufacturing a secondary battery for internal short-circuit experiments. On the other hand, the steps of (c) manufacturing the main separator and (d) manufacturing the auxiliary separator and attaching it to the main separator may be performed simultaneously, and the step of (d) manufacturing the auxiliary separator and attaching it to the main separator may be performed before the step of (c) manufacturing the main separator.

[0065] (a) Step of manufacturing the main first electrode (a) The step of manufacturing the main first electrode is to prepare a main first current collector 111 with a first blank surface 1111 partitioned off, as shown in Figure 10. Next, a main first coating layer 112 is coated onto the surface of the main first current collector 111. Then, the main first coating layer 112 coated on the first blank surface 1111 is removed. This allows the main first electrode 11 to be manufactured.

[0066] On the other hand, the main first coating layer 112 coated on the first blank surface 1111 can be removed by cutting with a cutting device (not shown) or by wiping it off with NMP (N-Methyl-2-pyrrolidone: first electrode material binder solvent) and then drying it (to vaporize the NMP).

[0067] Here, the first blank surface 1111 is partitioned off the edge of the main first current collector 111, which is intended to facilitate the attachment or removal of the auxiliary first electrode 15 that adheres to the first blank surface 1111. In particular, the first blank surface 1111 can be provided in a rectangular shape.

[0068] The first coating layer is applied to the entire surface of the main first current collector 111, including the first blank surface 1111, to the same thickness. The cutting device cuts and removes the first coating layer applied to the first blank surface 1111 so that the first blank surface 1111 is exposed to the outside. On the other hand, the main first electrode 11 is the positive electrode, and the first coating layer is the positive electrode coating layer.

[0069] (b) Step of manufacturing the second electrode (b) The step of manufacturing the second electrode is to prepare the second current collector 121 as shown in Figure 11. Next, the second coating layer 122 is coated onto the surface of the second current collector 121. Then the second electrode 12 can be manufactured.

[0070] Here, after coating the surface of the second current collector 121 with a second coating layer 122, a removal step is further included in which a portion of the surface of the second coating layer 122 corresponding to the first blank surface 1111 is removed. That is, the removal step removes the surface of the second coating layer 122 corresponding to the through hole 131 of the main separator 13 when the main first electrode 11 and the second electrode 12 are positioned between them. In particular, the removal step cuts off only a portion of the total thickness of the second coating layer 122 so that the second current collector 121 is not exposed to the outside.

[0071] On the other hand, the surface of the second coating layer 122 corresponding to the through hole 131 may be removed by cutting, or by repeatedly applying and peeling off adhesive tape.

[0072] As a result, the second coating layer 122 includes a first coating surface 1221 and a second coating surface 1222, and the first coating surface 1221 has a smaller thickness than the second coating surface 1222. Consequently, lithium precipitates can be induced to form on the first coating surface 1221 during charging and discharging.

[0073] (c) Steps to manufacture the main separator (c) The step of manufacturing the main separator is to prepare the main separator 13 as shown in Figure 12. Then, when the main separator 13 is placed between the main first electrode 11 and the second electrode 12, a part of the surface of the main separator 13 corresponding to the first blank surface 1111 is cut to form a through hole 131. Thus, a main separator 13 with a through hole 131 can be manufactured.

[0074] (d) Steps for manufacturing the auxiliary separator and attaching it to the main separator. (d) The step of manufacturing the auxiliary separator and attaching it to the main separator involves manufacturing an auxiliary separator 14 to close or open the through hole 131 formed in the main separator 13, as shown in Figure 13. Here, the auxiliary separator 14 has an area larger than the area of ​​the through hole. Next, the auxiliary separator 14 is attached to the main separator 13 while covering the through hole 131. At this time, the auxiliary separator 14 is attached to the main separator 13 in a detachable manner. That is, when the auxiliary separator 14 is attached to the main separator 13, the through hole 131 can be closed, and when the auxiliary separator 14 is removed from the main separator 13, the through hole 131 can be opened.

[0075] Here, the auxiliary separator 14 includes a separation surface 141 that is detachably attached to the main separator 13 while covering the through hole 131, and a gripping surface 142 that is located outside the main separator 13 when the separation surface 141 is attached to the main separator 13, for separating the auxiliary separator 14 from the main separator 13. Here, the auxiliary separator 14 and the main separator 13 can be bonded together using thermal fusion (heat and pressure).

[0076] On the other hand, the adhesive force between the auxiliary separator 14 and the main separator 13 is smaller than the adhesive force between the main first electrode 11 and the main separator 13.

[0077] On the other hand, the auxiliary separator 14 can be made of the same material as the main separator 13. However, in order to minimize the occurrence of steps, the thickness of the auxiliary separator 14 is smaller than the thickness of the main separator 13. On the other hand, in another embodiment, the auxiliary separator and the main separator may be made of different materials.

[0078] (e) Steps of manufacturing the auxiliary first electrode and attaching it to the main first electrode (e) The step of manufacturing the auxiliary first electrode and attaching it to the main first electrode involves manufacturing the auxiliary first electrode 15, as shown in Figure 14, which connects the main first current collector 111 and the second electrode 12 via the through hole 131 of the main separator 13 so as to cause an internal short circuit, or disconnects the connection.

[0079] In other words, the auxiliary first electrode 15 includes an auxiliary first current collector 151 having an attachment surface 1511 that is detachably attached to the first blank surface 1111, and an auxiliary first coating layer 152 that is coated on the outer surface of the attachment surface 1511. The attachment surface 1511 may have the same area as the first blank surface 1111.

[0080] In particular, the auxiliary first electrode 15 has the same polarity as the main first electrode 11. That is, the auxiliary first electrode 15 and the main first electrode 11 may be positive electrodes. Consequently, the second electrode 12 may be a negative electrode.

[0081] The auxiliary first current collector 151 includes a second blank surface 1512 located outside the main first electrode 11 when the attachment surface 1511 is attached to the first blank surface 1111, the second blank surface 1512 acting as a handle to separate the attachment surface 1511 of the auxiliary first current collector 151 from the first blank surface 1111.

[0082] On the other hand, the auxiliary first electrode 15 can have the same thickness as the main first coating layer 112. This increases the adhesion between the main first electrode 11 and the main separator, preventing the formation of steps.

[0083] On the other hand, the adhesive force between the auxiliary first electrode 15 and the first blank surface 1111 is smaller than the adhesive force between the main first electrode 11 and the main separator 13.

[0084] On the other hand, the auxiliary first electrode 15 can be attached to the first plain surface 1111 using adhesive tape. On the other hand, steps (d) and (e) may be performed simultaneously, or step (e) may be performed before step (d).

[0085] (f) Steps to manufacture an electrode assembly (f) The step of manufacturing the electrode assembly is as shown in Figure 2, in which the main separator 13 to which the auxiliary separator 14 is attached is placed between the main first electrode 11 to which the auxiliary first electrode 15 is attached and the second electrode 12 to manufacture the electrode assembly 10.

[0086] In this state, the electrode assembly 10 has the gripping surface 142 of the auxiliary separator 14 and the second blank surface 1512 of the auxiliary first electrode 15 exposed to the outside, and the auxiliary separator 14 and the auxiliary first electrode 15 can be removed from the electrode assembly 10 using the gripping surface 142 and the second blank surface 1512.

[0087] (g) Steps for manufacturing a secondary battery for internal short-circuit experiments (g) The step of manufacturing the secondary battery for internal short-circuit experiments is as shown in Figure 1: first, the electrode leads 30 are attached to the electrode tabs of the electrode assembly 10, and then the electrode assembly 10 and electrolyte (not shown) are placed in a pouch 20. At this time, the tips of the electrode leads 30 are pulled out of the pouch 20. Next, the pouch 20 is sealed to make it airtight. Then, the finished secondary battery 1 for internal short-circuit experiments can be manufactured. The following describes an experimental method using a secondary battery for internal short-circuit experiments according to the first embodiment of the present invention.

[0088] [Experimental method for a secondary battery for internal short-circuit testing according to the first embodiment of the present invention] Figure 15 is a flowchart showing the experimental method for the secondary battery 1 for internal short-circuit experiments according to the first embodiment of the present invention; Figure 16 is a plan view showing the charge-discharge steps; Figure 17 is a plan view showing the pouch 20 cutting step; Figure 18 is a cross-sectional view showing the auxiliary separator and auxiliary first electrode 15 removal steps; and Figure 19 is a cross-sectional view showing the crimping step of the secondary battery for internal short-circuit experiments.

[0089] As shown in Figure 15, the experimental method for a secondary battery for internal short-circuit testing according to the first embodiment of the present invention includes (A) a charging and discharging step, (B) a pouch cutting step, (C) a step of removing the auxiliary first electrode, (D) a step of removing the auxiliary separator, (E) a step of crimping the secondary battery for internal short-circuit testing, and (F) an internal short-circuit testing step.

[0090] (A) Charge and discharge step (A) In the charge-discharge step, as shown in Figure 16, the charge-discharge device 2 is connected to the electrode leads 30 of the secondary battery 1 for the internal short-circuit experiment, and then power is applied to the secondary battery 1 for the internal short-circuit experiment to repeatedly charge or discharge it. In this process, lithium deposits are generated on the first coating surface 1221 provided on the second coating layer 122 of the second electrode 12.

[0091] (B) Pouch incision step (B) As shown in Figure 17, once the charging and discharging of the secondary battery 1 for the internal short circuit experiment is complete, the pouch 20 of the secondary battery 1 for the internal short circuit experiment is cut open using the cutting device 3. At this time, the surface of the pouch 20 that is close to the second plain surface 1512 and the gripping surface 142 of the auxiliary separator 14 is cut open.

[0092] (C) Step of removing the auxiliary first electrode (C) The step of removing the auxiliary first electrode involves removing the auxiliary first electrode 15 attached to the main first electrode 11 of the electrode assembly 10 through the incision 21 of the pouch 20, as shown in Figure 18. Here, the auxiliary first electrode and the main first electrode are attached by adhesive tape, and the adhesive strength of the adhesive tape is weakened by the electrolyte, thereby allowing the auxiliary first electrode to be easily removed from the main first electrode.

[0093] In other words, by pulling the second blank surface 1512 of the auxiliary first electrode 15 that is exposed to the outside of the electrode assembly 10, the attachment surface 1511 of the auxiliary first electrode 15 that is attached to the first blank surface 1111 of the main first electrode 11 can be separated and removed.

[0094] (D) Step to remove the auxiliary separator (D) The auxiliary separator removal step involves removing the auxiliary separator 14 attached to the main separator 13 of the electrode assembly 10 through the incision 21 of the pouch 20, as shown in Figure 18. Here, the adhesive force between the auxiliary separator and the main separator is weakened by the impregnation with the electrolyte, thereby allowing the auxiliary separator to be easily removed from the main separator.

[0095] In other words, by pulling the gripping surface 142 of the auxiliary separator 14 exposed to the outside of the electrode assembly 10, the separating surface 141 of the auxiliary separator 14 attached to the main separator 13 separates and can be easily removed. This opens the through hole 131 of the main separator 13.

[0096] (E) Crimping step for secondary battery for internal short circuit experiment (E) The crimping step for the secondary battery for internal short-circuit experiment is as shown in Figure 19, in which the secondary battery 1 for internal short-circuit experiment is crimped using the crimping device 4 for 3 minutes to 1 hour, preferably 15 minutes to 30 minutes. As a result, the first blank surface 1111 of the main first current collector 111, the lithium precipitate, and the first coating surface 1221 of the second electrode 12 come into contact through the through hole 131 of the main separator 13, and an internal short circuit occurs. In other words, an internal short circuit can be generated between the main first electrode 11, the lithium precipitate, and the second electrode 12.

[0097] (F) Internal short circuit experiment step (F) The internal short-circuit experiment step involves measuring the voltage, resistance, and temperature of the internal short-circuit experiment secondary battery 1 when an internal short circuit occurs, using an internal short-circuit experiment apparatus (not shown). That is, by measuring and recording the voltage flowing through the electrode leads 30 of the internal short-circuit experiment secondary battery 1 when an internal short circuit occurs, it is possible to experiment with whether or not an internal short circuit occurs due to pressure, time, and voltage difference.

[0098] To explain in more detail, depending on the magnitude of the resistance during an internal short circuit, the following modes of voltage and temperature behavior appear. Mode 1: The voltage gradually decreases, the temperature rises slightly, then slowly decreases, and the experiment ends without ignition. Second: A mode in which a rapid drop in voltage and a rapid rise in temperature occur, leading to ignition. Third mode: A rapid decrease in voltage and a rapid increase in temperature occur, but the critical point for ignition is not reached, so the temperature gradually decreases thereafter, and ignition does not occur.

[0099] Therefore, (E) the crimping step of the secondary battery for internal short circuit experiment allows the internal short circuit experiment to be conducted using the secondary battery 1 for internal short circuit experiment. In describing other embodiments of the present invention below, the same reference numerals will be used for components having the same function as those described in the previously mentioned embodiments, and redundant explanations will be omitted.

[0100] [Secondary battery for internal short-circuit experiment according to the second embodiment of the present invention] Figure 20 is a separated perspective view showing an electrode assembly according to a second embodiment of the present invention; Figure 21 is a cross-sectional view showing the electrode assembly of Figure 20; Figure 22 is a cross-sectional view showing the electrode assembly from Figure 21 with the auxiliary first electrode 15 and auxiliary separator 14 removed; and Figure 23 is a cross-sectional view showing the electrode assembly from Figure 22 in a pressurized state. In describing the secondary battery for internal short-circuit experiments according to the second embodiment of the present invention, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0101] A secondary battery for internal short-circuit experiments according to a second embodiment of the present invention includes, as shown in Figure 20, an electrode assembly 10', a pouch (not shown) for housing the electrode assembly 10', and electrode leads 30 connected to the electrode assembly 10 with their tips extended outside the pouch.

[0102] Here, the secondary battery for internal short-circuit experiments according to the second embodiment of the present invention has the same configuration as the secondary battery for internal short-circuit experiments according to the first embodiment of the present invention described above, except for the second electrode 12, so redundant explanations will be omitted.

[0103] The second electrode 12, as shown in Figure 21, includes a second current collector 121 and a second coating layer 122 coated on the surface of the second current collector 121. That is, the second coating layer 122 is coated on both surfaces of the second current collector 121, as shown in Figure 21. The second current collector 121 includes an electrode tab for connecting to the electrode lead 30.

[0104] Here, unlike the second electrode 12 included in the secondary battery for internal short-circuit experiments according to the first embodiment, the second electrode 12 does not have a first coating surface 1221 formed on it, and as a result, lithium deposits do not form on the surface of the second coating layer 122 of the second electrode 12 during charging and discharging.

[0105] In the secondary battery for internal short-circuit experiments according to the second embodiment of the present invention having such a structure, as shown in Figure 22, when the auxiliary first electrode 15 and the auxiliary separator 14 are removed from the electrode assembly 10', the first blank surface 1111 of the main first electrode 11 and the second coating layer 122 of the second electrode 12 can be connected facing each other through the through hole 131 of the main separator 13.

[0106] Furthermore, as shown in Figure 23, when the secondary battery for internal short-circuit experiments according to the second embodiment of the present invention is crimped, the first blank surface 1111 of the main first electrode 11 and the second coating layer 122 of the second electrode 12 come into contact through the through hole 131 of the main separator 13, thereby generating an internal short circuit. Therefore, the secondary battery for internal short-circuit experiments according to the second embodiment of the present invention can be used to experiment on internal short circuits between the main first electrode 11 and the second electrode 12.

[0107] [Example of experiment] Experiment preparation The purpose of this experiment is to determine the effect of lithium precipitates and the critical point at which ignition occurs when an internal short circuit (in hazardous and non-hazardous areas) occurs due to lithium precipitates.

[0108] The experimental method involves preparing a secondary battery for internal short-circuit experiments according to the first embodiment of the present invention (positive electrode current collector - lithium precipitate - charging negative electrode) (hereinafter referred to as Experiment 1) and a secondary battery for internal short-circuit experiments according to the second embodiment (positive electrode current collector - charging negative electrode) (hereinafter referred to as Experiment 2). Then, the unit area (mm²) of Experiment 1 and Experiment 2 is measured. 2 Add a unit pressure (MPa) of 0.3, 0.5, and 1.0 to the values ​​of 1.76 (1.5Φ), 7.06 (3.0Φ), and 79.62 (5.0Φ).

[0109] Experimental results for Experiment 1 As shown in Experimental Table 1 below, in Experimental Object 1, an internal short circuit occurred due to lithium precipitates, and the critical point for ignition could not be identified due to the high resistance of the lithium precipitates. In other words, it can be confirmed that no ignition occurred in Experimental Object 1.

[0110] [Table 1]

[0111] <Experimental Table 1> As shown in Experimental Table 2 below, in Experimental Object 2, as the pressure per unit area increases, the critical point for ignition due to internal short circuit can be confirmed. In other words, in Experimental Object 2, as the pressure increases, it can be confirmed that ignition occurs when the short-circuit area increases.

[0112] [Table 2]

[0113] <Experimental Table 2>Therefore, by referring to Experimental Tables 1 and 2, an experimental table 3 like the one below can be created, and in this way, an internal short circuit can be experimented on using the secondary batteries for internal short circuit experiments according to the first and second embodiments of the present invention.

[0114] [Table 3]

[0115] <Experimental Table 3> The scope of the present invention is indicated by the claims described below rather than by the detailed description above, and various embodiments are possible derived from the meaning and scope of the claims and their equivalent concepts. [Explanation of symbols]

[0116] 1: Secondary battery for internal short-circuit experiment 10: Electrode assembly 11: Main 1st electrode 111: Main No. 1 Current Collector 1111: 1st plain ground 112: Main first coating layer 12:Second electrode 121: Second current collector 122: Second coating layer 1221: First coated surface 1222: Second coating surface 13: Main separator 131: Through hole 14: Auxiliary separator 141: Separation surface 142: Gripping surface 15: Auxiliary 1st electrode 151: Auxiliary No. 1 Current Collector 1511: Adhesion surface 1512: 2nd plain ground 152: Auxiliary first coating layer 20: Pouch 21: Incision site 30: Electrode Leads 31: First electrode lead 32: Second electrode lead 2: Charge / discharge device 3: Incision device 4: Crimping device

Claims

1. Electrode assembly and A pouch for housing the electrode assembly, Includes, The electrode assembly is A main first electrode comprising a main first current collector and a main first coating layer coated on the remaining surface excluding the first plain surface partitioned by the main first current collector, A second electrode comprising a second current collector and a second coating layer coated on the surface of the second current collector, A main separator is disposed between the main first electrode and the second electrode, and has a through hole formed at a position corresponding to the first blank surface, An auxiliary separator is detachably attached to the main separator and closes or opens the through hole, An auxiliary first electrode is detachably attached to the first blank surface and connects the first blank surface of the main first current collector and the second electrode via the through hole that is opened when removed, causing an internal short circuit. A secondary battery for internal short-circuit experiments, including one for this purpose.

2. The auxiliary first electrode is, An auxiliary first current collector having an attachment surface formed thereon that is detachably attached to the first blank surface, A secondary battery for internal short-circuit testing according to claim 1, comprising an auxiliary first coating layer coated on the aforementioned adhesion surface.

3. The first blank surface is formed on the edge of the main first current collector, as described in claim 2, for internal short-circuit testing of a secondary battery.

4. The aforementioned auxiliary first current collector is The secondary battery for internal short-circuit experiments according to claim 3, further comprising a second blank surface located outside the main first electrode when the adhesion surface adheres to the first blank surface, for separating the auxiliary first current collector from the first blank surface.

5. The aforementioned auxiliary separator is, A separating surface that is detachably attached to the main separator while covering the through hole, A secondary battery for internal short-circuit experiments according to claim 1, comprising: a gripping surface located outside the main separator when the separating surface is in contact with the main separator, for separating the auxiliary separator from the main separator.

6. The secondary battery for internal short-circuit experiments according to claim 1, wherein the auxiliary first electrode has the same thickness as the main first coating layer.

7. The aforementioned second coating layer is It includes a first coating surface coated on the surface of the second current collector corresponding to the through hole, and a second coating surface coated on the surface of the second current collector that is not coated with the first coating surface, The secondary battery for internal short-circuit experiments according to claim 1, wherein the first coating surface has a thickness smaller than the second coating surface.

8. The secondary battery for internal short-circuit experiments according to claim 2, wherein the main first electrode and the auxiliary first electrode have the same polarity.

9. The secondary battery for internal short-circuit experiments according to claim 8, wherein the main first electrode and the auxiliary first electrode are positive electrodes.

10. The secondary battery for internal short-circuit experiments according to claim 1, wherein the second electrode is the negative electrode.

11. The auxiliary first electrode is detachably attached to the first blank surface via adhesive tape, as described in claim 1, for internal short-circuit experiments.

12. The secondary battery for internal short-circuit testing according to claim 1, wherein the auxiliary separator and the main separator are detachably attached by thermal fusion.

13. (a) After preparing a main first current collector in which a first blank surface is partitioned, a main first coating layer is coated onto the surface of the main first current collector, and then the main first coating layer coated on the first blank surface is removed to manufacture a main first electrode; (b) A step of manufacturing a second electrode by coating the surface of the second current collector with a second coating layer, (c) A step of manufacturing a main separator in which a through hole is formed by cutting a portion of the surface corresponding to the first blank surface when it is placed between the main first electrode and the second electrode, (d) After manufacturing an auxiliary separator for closing or opening the through hole, the step of attaching the auxiliary separator to the main separator in a manner that covers the through hole, (e) Manufacturing an auxiliary first electrode that connects the main first current collector and the second electrode via the through hole in such a way that an internal short circuit occurs, or disconnects the connection, and then attaching the auxiliary first electrode to the first blank surface in a detachable manner, A method for manufacturing a secondary battery for internal short-circuit experiments, including the invention of the secondary battery.

14. In step (e) above, the auxiliary first electrode is A method for manufacturing a secondary battery for internal short-circuit testing according to claim 13, comprising an auxiliary first current collector having an attachment surface formed thereon that is detachably attached to the first blank surface, and an auxiliary first coating layer coated on the outer surface of the attachment surface.

15. In step (a) above, the first blank surface is defined by the edge of the main first current collector, The method for manufacturing a secondary battery for internal short-circuit testing according to claim 14, wherein in step (e), the auxiliary first current collector is located outside the main first electrode when the adhesion surface is in contact with the first blank surface, and includes a second blank surface for separating the auxiliary first current collector from the first blank surface.

16. Step (b) further includes, after coating the second coating layer, cutting the surface of the second coating layer corresponding to the through hole when the main separator is positioned between the main first electrode and the second electrode, The method for manufacturing a secondary battery for internal short-circuit testing according to claim 13, wherein the second coating layer includes a cut first coating surface and an uncut second coating surface, and the first coating surface has a thickness smaller than the second coating surface.

17. After step (e), (f) a step of manufacturing an electrode assembly by placing the main separator, to which the auxiliary separator is attached, between the main first electrode, to which the auxiliary first electrode is attached, and the second electrode, (g) The method for manufacturing a secondary battery for internal short-circuit testing according to claim 13, further comprising the step of housing the electrode assembly in a pouch and then sealing the pouch to manufacture the secondary battery for internal short-circuit testing.

18. A method for manufacturing a secondary battery for internal short-circuit testing according to any one of claims 13 to 17, wherein the main first electrode and the auxiliary first electrode have the same polarity.

19. (A) The step of applying a voltage to the secondary battery for internal short-circuit testing described in any one of claims 1 to 12 to charge and discharge it, (B) The step of cutting open the pouch of the secondary battery for the internal short circuit experiment, (C) The step of removing the auxiliary first electrode attached to the main first electrode of the electrode assembly through the incision of the pouch, (D) The step of removing the auxiliary separator that has adhered to the main separator of the electrode assembly through the cut portion of the pouch, and opening the through hole of the main separator, (E) The step of crimping the secondary battery for internal short-circuit experiment and bringing the first blank surface of the main first current collector and the second electrode into contact through the through hole to cause an internal short circuit, An experimental method for a secondary battery used in internal short-circuit experiments, including the method described above.

20. The method for experimentally testing a secondary battery for internal short-circuit testing according to claim 19, wherein in step (A), the second coating layer of the second electrode is composed of a first coating surface and a second coating surface having a greater thickness than the first coating surface, and lithium precipitates are generated on the first coating surface corresponding to the auxiliary first electrode during charging and discharging.

Images