Battery case, battery case molding device, and method for manufacturing secondary battery

Abstract

The present invention relates to a battery case, a battery case molding apparatus, and a method for manufacturing a secondary battery, and provides a battery case, a battery case molding apparatus, and a method for manufacturing a secondary battery that prevent insulation failure by allowing sealing material melted from a sealing portion to be contained in an insulation failure prevention portion, thereby improving productivity and quality. A battery case according to one embodiment of the present invention is a battery case for a pouch-type secondary battery having an electrode assembly accommodated therein. The battery case includes a first case, a second case covering the first case from above, a cup portion provided in at least one of the first case or the second case and forming a space for accommodating the electrode assembly, and a side portion formed along outer peripheries of the first case and the second case, the side portion including a seal portion where the first case and the second case abut and seal, and an insulation failure prevention portion formed between the seal portion and the cup portion and for receiving a sealing material melted from the seal portion.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0016539 dated February 8, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery case, a battery case molding device, and a method for manufacturing a secondary battery. [Background technology]

[0003] A secondary battery is a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and the types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium-ion polymer batteries. These secondary batteries are used not only in small products such as digital cameras, notebook computers, mobile phones, PDAs (registered trademarks), and E-bikes, but also in large products that require high output, such as electric vehicles and hybrid vehicles, power storage devices that store surplus generated power and renewable energy, and backup power storage devices.

[0004] Such secondary batteries are classified into pouch type and can type depending on the material of the battery case that houses the electrode assembly. The pouch type houses the electrode assembly in a pouch made of a flexible polymer material that has no uniform shape, while the can type houses the electrode assembly in a case made of a material such as metal or plastic that has a uniform shape.

[0005] FIG. 1 is a side cross-sectional view showing a battery case of a conventional pouch-type secondary battery. A battery case 1 of a pouch-type secondary battery is manufactured by pressing a flexible pouch film to form a cup portion. The pouch film has a multi-layer structure in which a plurality of layers are laminated, and in particular, the innermost layer is a sealant layer formed on the innermost layer of the pouch film, which is in direct contact with the electrode assembly, has chemical resistance and thermal adhesiveness against the electrolyte, and also serves as a sealant. The innermost layer is mainly formed of a polyolefin-based resin, and is preferably formed of polypropylene (PP).

[0006] When the cup of the battery case is formed, the electrode assembly is placed in the receiving space of the cup, and the sides are pressurized and heated by a sealing tool to manufacture a secondary battery by a heat sealing method. Although it is preferable to perform the heat sealing method for a long time at a low temperature as possible, it is necessary to perform the sealing for a short time at a high temperature and with a high pressure in order to increase the production speed.

[0007] However, when the side is pressurized at high temperature and pressure, a part of the sealant layer, which is the innermost layer, is melted and extruded toward the receiving space of the cup part, and the extruded sealant layer may be irregularly positioned in the receiving space of the cup part or may protrude toward the receiving space to form poly-balls. In this case, the extruded sealant layer may come into contact with the electrode assembly to contaminate the electrode assembly, and the seal thickness of the seal part may become thin, which may cause direct insulation failure or insulation failure due to external physical impact.

[0008] Therefore, there is a need to develop a manufacturing method for a battery case and a secondary battery that can ensure product quality while improving the productivity of the sealing process. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been devised to solve the above problems, and an object of the present invention is to provide a battery case, a battery case molding apparatus, and a method for manufacturing a secondary battery, which prevent insulation failure by allowing sealing material melted from a sealing portion to be contained in an insulation failure prevention portion, thereby improving productivity and quality. [Means for solving the problem]

[0010] A battery case according to one embodiment of the present invention is a battery case for a pouch-type secondary battery having an electrode assembly accommodated therein. The battery case includes a first case, a second case covering the first case from above, a cup portion provided in at least one of the first case or the second case and forming a space for accommodating the electrode assembly, and a side portion formed along outer peripheries of the first case and the second case, the side portion including a seal portion where the first case and the second case abut and seal, and an insulation failure prevention portion formed between the seal portion and the cup portion and for receiving a sealing material melted from the seal portion.

[0011] The insulation failure prevention portion may be recessed from the inside to the outside of the side portion in a depth direction of the cup portion.

[0012] The insulation failure prevention portion may have an inner surface formed as a curved surface.

[0013] The insulation failure prevention portion may be formed to have a depth shallower than a depth of the cup portion.

[0014] The insulation failure prevention portion may be formed at a position corresponding to each other on a side portion formed on the first case and a side portion formed on the second case.

[0015] The insulation failure prevention portion may be formed in an unsealed state such that the side portion formed on the first case and the side portion formed on the second case do not come into contact with each other.

[0016] The insulation failure prevention portion may be formed continuously or intermittently along the periphery of the cup portion between the sealing portion and the cup portion.

[0017] The side portion may further include a movement prevention portion that connects the insulation failure prevention portion and the cup portion and prevents a sealing material accommodated in the insulation failure prevention portion from moving to the cup portion.

[0018] The movement prevention portion may be formed in an unsealed state on a side portion formed on the first case and a side portion formed on the second case so as not to come into contact with each other.

[0019] The movement prevention portion may be formed to have a thickness greater than that of the sealing portion and less than that of the insulation failure prevention portion.

[0020] The sealing material melted from the sealing portion can protrude into the insulation failure prevention portion.

[0021] A battery case molding apparatus according to another embodiment of the present invention is an apparatus for molding a battery case for a pouch-type secondary battery in which an electrode assembly is housed, the apparatus including: a die plate on which a pouch film is placed and on which a molding portion is formed that is recessed or penetrated downward from the upper surface and on which a groove is formed around the molding portion; a stripper that pressurizes and fixes the pouch film at an upper portion of the die plate and on which a punch hole is formed that penetrates from top to bottom at a position corresponding to the molding portion and on which a rib is formed around the punch hole facing the groove; and a punch that is drawn into the molding portion of the die plate through the punch hole of the stripper and forms a cup portion in the pouch film.

[0022] According to yet another embodiment of the present invention, a method for manufacturing a pouch-type secondary battery having an electrode assembly accommodated therein includes forming a battery case including a cup portion and an insulation failure prevention portion, and accommodating the electrode assembly in the cup portion and sealing a seal portion of the battery case. The forming of the battery case includes placing a pouch film on a die plate having a molding portion and a groove formed around the molding portion, a stripper having a punch hole and a rib formed around the punch hole pressingly fastens the pouch film on an upper portion of the die plate, and the rib is drawn into the groove to form the insulation failure prevention portion in the pouch film, and a punch is drawn into the molding portion of the die plate through the punch hole of the stripper to form the cup portion in the pouch film. Effect of the Invention

[0023] In the battery case according to the present invention, the sealing material melted from the sealing portion is contained in the insulation failure prevention portion, thereby minimizing irregular positioning or protrusion of the leaked sealing material in the cup portion, thereby preventing insulation failure. The space formed in the insulation failure prevention portion can also act as a buffer against external physical impacts, thereby preventing further insulation failure and improving the safety of the secondary battery.

[0024] In addition, even if sealing is performed at high temperatures and pressures, the sealing material is contained in the insulation failure prevention part, so the speed of the sealing process can be increased, thereby ensuring both productivity and the quality of the battery case. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a side cross-sectional view showing a battery case of a conventional pouch-type secondary battery. [Diagram 2] 1 is a perspective view showing a battery case according to an embodiment of the present invention and an electrode assembly housed in the battery case; [Diagram 3] FIG. 2 is a side cross-sectional view showing a battery case according to one embodiment of the present invention. [Figure 4] FIG. 11 is a perspective view showing a battery case molding device according to another embodiment of the present invention. [Diagram 5] FIG. 4 is a side cross-sectional view showing a battery case molding device according to another embodiment of the present invention. [Figure 6] 10 is a flowchart showing a method for manufacturing a secondary battery according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] In the following, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention can be realized in several different forms, and is not limited to or by the following embodiments.

[0027] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the description or related prior art that may unnecessarily obscure the gist of the present invention will be omitted, and when adding reference symbols to components in each drawing in this specification, the same or similar reference symbols will be used for the same or similar components throughout the specification.

[0028] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concept of a term in order to best describe his or her invention.

[0029] One embodiment Fig. 2 is a perspective view showing a battery case according to one embodiment of the present invention and an electrode assembly housed in the battery case, and Fig. 3 is a side cross-sectional view showing a battery case according to one embodiment of the present invention.

[0030] 2 and 3, a battery case 100 according to one embodiment of the present invention is a pouch-type secondary battery battery case 100 in which an electrode assembly 10 is housed, and includes a first case 110, a second case 120, a cup portion 130, and a side portion 140.

[0031] First, the first case 110 and the second case 120 are formed by molding a pouch film, and the first case 110 is located at the bottom, and the second case 120 covers the first case 110 from above. At this time, the first case 110 and the second case 120 may be separated and the second case 120 may cover the first case 110, but the present invention is not limited thereto. The first case 110 and the second case 120 may be formed in one pouch film, and the second case 120 may be folded and covered on the top of the first case 110 by a folding device.

[0032] The pouch film may be formed in a multi-layer structure in which a plurality of layers are laminated, and may be formed by laminating a metal layer on an inner layer and an outer layer on the metal layer. The inner layer is a layer located at the innermost part of the pouch film, and serves as a sealant having chemical resistance and thermal adhesiveness to the electrolyte, and is mainly formed of a polyolefin resin, and preferably polypropylene (PP). The metal layer is a layer interposed between the inner layer and the outer layer, and corresponds to a layer that maintains the mechanical strength of the pouch film and serves as a barrier against moisture and oxygen. The metal layer may be formed of an alloy of iron (Fe), carbon (C), chromium (Cr) and manganese (Mn), an alloy of iron (Fe), carbon (C), chromium (Cr) and nickel (Ni), and the like, and preferably aluminum (Al). The outer layer is a layer formed at the outermost part of the pouch film, and serves to protect the battery from external impact, and is required to have insulating properties and heat resistance since it comes into direct contact with hardware. The material of the outer layer may include one single layer selected from polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), nylon, low density polyethylene (LDPE), and high density polyethylene (HDPE), or a composite layer of two or more types.

[0033] The cup portion 130 is provided in at least one of the first case 110 or the second case 120, and a space is formed to accommodate the electrode assembly 10. The cup portion 130 may be formed only in the first case 110, only in the second case 120, or both in the first case 110 and the second case 120.

[0034] The side portion 140 refers to a region formed along the outer periphery of the first case 110 and the second case 120. For example, in the case of a battery case 100 in which the first case 110 and the second case 120 are formed in one pouch film and the second case 120 is folded over the top of the first case 110 to cover it, the side portion 140 may refer to an edge formed along the outer periphery of the first case 110 and the second case 120, excluding the region folded between the first case 110 and the second case 120. However, in the case in which the second case 120 covers the first case 110 in a state in which the first case 110 or the second case 120 is separated, the side portion 140 may refer to an edge of each of the separated first case 110 and second case 120.

[0035] Meanwhile, the side portion 140 of the battery case 100 according to one embodiment of the present invention includes a seal portion 141 where the first case 110 and the second case 120 come into contact and are sealed, and an insulation failure prevention portion 142 formed between the seal portion 141 and the cup portion 130 and receiving the sealing material melted from the seal portion 141. Therefore, in the battery case 100 according to one embodiment of the present invention, the sealing material melted from the seal portion 141 can protrude into the insulation failure prevention portion 142.

[0036] In this way, even if the sealing material P melted by heating and pressurization flows out of the sealing portion 141, the sealing material P is contained in the insulation failure prevention portion 142, thereby preventing the sealing material P from being located locally in irregular positions and causing insulation failure. Furthermore, even if the sealing material P melts, it is not directly exposed to the cup portion 130 but is contained in the insulation failure prevention portion 142, so that sealing can be performed at a higher temperature and pressure, and the process speed can be increased. This ensures both productivity and the quality of the battery case 100.

[0037] The insulation failure prevention unit 142 will be described in detail below with continued reference to FIGS.

[0038] The insulation failure prevention part 142 may be recessed from the inside to the outside of the side part 140 in the depth direction of the cup part 130. Here, the inside of the side part 140 may refer to one side where the first case 110 and the second case 120 face each other when the second case 120 covers the upper part of the first case 110, and the outside may refer to the opposite side of the inside of the first case 110 and the second case 120. At the same time, when the second case 120 covers the upper part of the first case 110 to distinguish the inside and the outside of the battery case 100, the side located inside the battery case 100 may be referred to as the inside.

[0039] In this manner, since the insulation failure prevention portion 142 of the battery case 100 according to the present invention is formed by being recessed from the inside to the outside of the side portion 140, a space is provided in the side portion 140, and the sealing material P that melts and comes out from the sealing portion 141 can be accommodated in the space, and the space can also act as a buffer against external physical impacts, thereby preventing further insulation failure from occurring and improving the safety of the secondary battery after sealing.

[0040] Meanwhile, the insulation failure prevention part 142 may have a curved inner surface. Here, the inner surface may refer to one surface of the insulation failure prevention part 142 formed on the inner side of the side part 140. The insulation failure prevention part 142 is a space formed by being recessed as described above, and the molten sealing material P may flow out and be accommodated in the insulation failure prevention part 142, but if the sealing material P does not flow out, it may remain in an empty space state. In this case, if an external impact is applied, there is a risk that the battery case 100 may break. However, in the present invention, since the inner surface of the insulation failure prevention part 142 is formed as a curved surface, even if the molten sealing material P is not accommodated, the risk of the battery case 100 breaking due to the external impact can be minimized.

[0041] Next, the depth D1 of the insulation failure prevention part 142 may be formed shallower than the depth D2 of the cup part 130. When the second case 120 covers the upper part of the first case 110, the insulation failure prevention part 142 has a shape that protrudes outward from the battery case 100. At this time, if the depth D1 of the insulation failure prevention part 142 is formed deeper than the depth D2 of the cup part 130, the ease of storing the secondary battery cell is significantly reduced and the risk of damage to the insulation failure prevention part 142 is significantly increased. In addition, since the insulation failure prevention part 142 is formed with a relatively narrow width, if the depth is formed deeper than the depth of the cup part 130, there is a problem that the moldability is significantly reduced and it is difficult to maintain the shape even after molding.

[0042] Therefore, the depth D1 of the insulation failure prevention portion 142 is formed shallower than the depth D2 of the cup portion 130, so that the sealing material P molten from the seal portion 141 can be properly contained while ensuring the moldability and structural stability of the insulation failure prevention portion 142.

[0043] Also, the insulation failure prevention part 142 may be formed at a position corresponding to each other on the side part 140 formed on the first case 110 and the side part 140 formed on the second case 120. This minimizes the area occupied by the insulation failure prevention part 142 and ensures a larger area for the sealing part 141, thereby strengthening the sealing force and ensuring ease of sealing, and at the same time, maximizing the space in which the molten sealing material P can be accommodated.

[0044] The insulation failure prevention part 142 may be formed in an unsealed state in the side part 140 formed in the first case 110 and the side part 140 formed in the second case 120 so as not to abut against each other. In the past, a step or groove was provided in a battery case sealing device, not a battery case molding device, and a protrusion or bulge was formed in the sealed part of the battery case during the process of sealing the pouch-type battery case. However, according to the conventional sealing device or sealing method, the battery case remains in a sealed state even at the protrusion or bulge, and there is a problem that the molten sealing material still flows into the cup part from the sealed part adjacent to the cup part, resulting in insulation failure. In addition, there is a problem that it is difficult to expect a buffering role when a physical impact is applied from the outside of the battery case.

[0045] However, in the battery case 100 according to the present invention, the insulation failure prevention part 142 is provided with a space formed in an unsealed state, and therefore, the insulation failure prevention part 142 can sufficiently contain the molten sealing material P that flows out from the sealing part 141, thereby preventing the sealing material P from being exposed to the cup part 130, and the area where the sealing material P is not contained remains as an empty space, thereby serving as a buffer space that absorbs external impacts.

[0046] Meanwhile, the insulation failure prevention part 142 may be formed continuously or intermittently along the circumference of the cup part 130 between the sealing part 141 and the cup part 130 .

[0047] The insulation failure prevention part 142 being continuously formed may mean that it is formed as one linearly connected along the periphery of each cup part 130 in the first case 110 or the second case 120. In this case, there is an advantage that the exposure of the melted sealing material P from the sealing part 141 to the cup part 130 can be minimized, and the prevention and buffering effect of insulation failure can be maximized.

[0048] Meanwhile, the insulation failure prevention parts 142 being formed discontinuously may mean that the insulation failure prevention parts 142 are formed along the periphery of each cup part 130 in the first case 110 or the second case 120, and a plurality of insulation failure prevention parts 142 are formed at regular intervals. In this case, by performing additional sealing in the areas between the plurality of insulation failure prevention parts 142, it is possible to simultaneously prevent insulation failure and strengthen the sealing force.

[0049] The side portion 140 of the battery case 100 according to an embodiment of the present invention may further include a movement prevention portion 143 that connects the insulation failure prevention portion 142 and the cup portion 130 and prevents the sealing material P accommodated in the insulation failure prevention portion 142 from moving to the cup portion 130. That is, the movement prevention portion 143 is formed between the recessed insulation failure prevention portion 142 and the cup portion 130, protruding from the outside to the inside relative to the insulation failure prevention portion 142 and the cup portion 130, thereby preventing the sealing material P accommodated in the insulation failure prevention portion 142 from moving to the cup portion 130.

[0050] In addition, the thickness T1 of the movement prevention part 143 may be formed to be thicker than the thickness T2 of the seal part 141 and thinner than the thickness T3 of the insulation failure prevention part 142. In particular, since the thickness T1 of the movement prevention part 143 is formed to be thinner than the thickness T3 of the insulation failure prevention part 142, it is possible to prevent the seal material P accommodated in the insulation failure prevention part 142 from moving to the cup part 130.

[0051] Meanwhile, the movement prevention part 143 may be formed in an unsealed state in the side part 140 formed in the first case 110 and the side part 140 formed in the second case 120 so as not to abut against each other. As a result, the movement prevention part 143 can be provided together with the above-mentioned insulation failure prevention part 142 while forming a space in an unsealed state, and it is possible to prevent the sealing material P accommodated in the insulation failure prevention part 142 from moving to the cup part 130. In addition, the movement prevention part 143 can accommodate a part of the molten sealing material P flowing out from the seal part 141, and when the sealing material P is not filled, it remains as an empty space, and can also play the role of a buffer space that absorbs external impacts.

[0052] Other embodiments Fig. 4 is a perspective view showing a battery case molding apparatus according to another embodiment of the present invention, and Fig. 5 is a side cross-sectional view showing a battery case molding apparatus according to another embodiment of the present invention.

[0053] Another embodiment of the present invention differs from the embodiment of the present invention in that the present invention is an apparatus for molding the battery case 100 according to the embodiment. Therefore, the configuration of the battery case 100 can be understood in the same manner as that described in the above embodiment and shown in Figures 2 and 3, and the same effects can be expected therefrom.

[0054] 4 and 5, a battery case molding apparatus 200 according to another embodiment of the present invention is an apparatus for molding a battery case of a pouch-type secondary battery in which an electrode assembly is housed, and may include a die plate 210, a stripper 220, and a punch 230.

[0055] 2 to 5. First, a pouch film is placed on the upper surface of the die plate 210, and a molding portion 211 is formed by being recessed or penetrated downward from the upper surface, and a groove 212 is formed around the molding portion 211. A punch 230 (described later) is inserted into the molding portion 211 to form the cup portion 130 of the battery case 100, and a rib 222 (described later) is inserted into the groove 212 to form the insulation failure prevention portion 142 of the battery case 100.

[0056] The stripper 220 presses and fixes the pouch film on the upper part of the die plate 210, and a punch hole 221 is formed in a shape penetrating the upper and lower surfaces at a position corresponding to the forming part 211, and a rib 222 facing the groove 212 is formed around the punch hole 221. A conventional general stripper is configured to only play a role in fixing the pouch film, but in the battery case forming apparatus 200 according to the present invention, a rib 222 is further formed around the punch hole 221 of the stripper 220, so that the stripper 220 can form the insulation failure prevention part 142 while fixing the pouch film. Here, the shape of the rib 222 may be formed to correspond to the shape of the groove 212 and the insulation failure prevention part 142 of the battery case 100.

[0057] Punch 230 is drawn into forming section 211 of die plate 210 through punch hole 221 of stripper 220, and forms cup section 130 in the pouch film. That is, with the pouch film fixed by stripper 220, punch 230 pressurizes the pouch film, and the pouch film is stretched, thereby forming cup section 130 into a shape corresponding to punch 230 and forming section 211.

[0058] As described above, in the battery case molding apparatus 200 according to another embodiment of the present invention, the grooves 212 are formed in the die plate 210, and the ribs 222 are further formed in the stripper 220, so that the insulation failure prevention part 142 can be formed together with the cup part 130 of the battery case 100. The detailed configuration of the insulation failure prevention part 142 formed in the battery case 100 and the effects thereof can be understood in the same manner as described in the above embodiment.

[0059] Further embodiments FIG. 6 is a flowchart showing a method for manufacturing a secondary battery according to still another embodiment of the present invention.

[0060] Yet another embodiment of the present invention differs in that it is a method for molding the battery case 100 according to the one embodiment using the battery case molding apparatus 200 according to the other embodiment described above. Therefore, the configurations of the battery case 100 and the battery case molding apparatus 200 can be understood in the same way as those described above and shown in Figures 2 to 5, and the same effects can be expected therefrom.

[0061] 2 to 5 as well as FIG. 6, a method for manufacturing a secondary battery according to still another embodiment of the present invention is a method for manufacturing a pouch-type secondary battery having an electrode assembly housed therein, and includes a step S10 of forming a battery case 100 including a cup portion 130 and an insulation failure prevention portion 142, and a step S20 of housing the electrode assembly 10 in the cup portion 130 and sealing a seal portion 141 of the battery case 100. As such, the method for manufacturing a secondary battery according to the present invention does not form the insulation failure prevention portion 142 in the step S20 of sealing the seal portion 141, but forms the insulation failure prevention portion 142 in the step S10 of forming the battery case 100 prior to the sealing step.

[0062] To explain this in more detail, step S10 of forming the battery case 100 includes step S11 of placing a pouch film on a die plate 210 having a molding portion 211 and a groove 212 around the molding portion 211, step S12 of a stripper 220 having a punch hole 221 and a rib 222 around the punch hole 221 pressingly fixing the pouch film on the upper part of the die plate 210 and the rib 222 being drawn into the groove 212 to form an insulation failure prevention portion 142 in the pouch film, and step S13 of a punch 230 being drawn into the molding portion 211 of the die plate 210 through the punch hole 221 of the stripper 220 to form a cup portion 130 in the pouch film.

[0063] In this manner, the method for manufacturing a secondary battery according to the present invention forms the insulation failure prevention part 142 before step S20 of sealing the sealing part 141, so that even if the molten sealing material P of the battery case 100 leaks out during the sealing step S20, it is contained in the insulation failure prevention part 142, thereby minimizing insulation failure.

[0064] Meanwhile, the step S20 of sealing the sealing portion 141 is a step of heating and pressurizing the sealing portion 141 of the side portion 140 using a bar-type or roller-type sealing tool to seal it. If necessary, in order to prevent mismatch between the first case 110 and the second case 120, a pre-sealing process may be performed to seal a portion of the sealing portion 141, and then a main sealing process may be performed to seal the entire sealing portion 141.

[0065] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the technical spirit of the present invention and the equivalent scope of the claims described below by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0066] 10: Electrode assembly 100: Battery case 110: First case 120: Case 2 130: Cup section 140: Side section 141: Seal part 142: Insulation failure prevention part 143: Movement prevention part P: Sealing material D1: Depth of insulation failure prevention part D2: Depth of the cup T1: Thickness of the anti-movement part T2: Thickness of the seal T3: Thickness of insulation failure prevention part 200: Battery case molding device 210: Die plate 211: Molding section 212: Groove 220: Stripper 221: Punch hole 222: Rib 230: Punch

Claims

1. A battery case for a pouch-type secondary battery in which an electrode assembly is housed, The first case, a second case covering the first case from above; a cup portion provided in at least one of the first case or the second case, the cup portion defining a space for receiving the electrode assembly; a side portion formed along an outer periphery of the first case and the second case, The side portion is a seal portion where the first case and the second case come into contact with each other to be sealed; an insulation failure prevention portion formed between the sealing portion and the cup portion, for receiving sealing material melted from the sealing portion.

2. The insulation failure prevention unit includes: The battery case according to claim 1 , wherein the side portion is recessed from the inside to the outside in a depth direction of the cup portion.

3. The insulation failure prevention unit includes: The battery case according to claim 1 , wherein the inner surface is formed as a curved surface.

4. The depth of the insulation failure prevention portion is The battery case according to claim 1 , wherein the depth of the recess is shallower than the depth of the cup portion.

5. The insulation failure prevention unit includes: The battery case according to claim 1 , wherein the first case and the second case are formed at side portions at positions corresponding to each other on the side portions of the first case and the second case.

6. The insulation failure prevention unit includes: The battery case according to claim 5 , wherein the side portions formed on the first case and the side portions formed on the second case are formed in an unsealed state so as not to abut against each other.

7. The insulation failure prevention unit includes: The battery case according to claim 1 , wherein the sealing portion and the cup portion are formed continuously or intermittently along a circumference of the cup portion.

8. The side portion is The battery case according to claim 1 , further comprising a movement prevention part connecting the insulation failure prevention part and the cup part and preventing a sealing material contained in the insulation failure prevention part from moving to the cup part.

9. The movement prevention portion is The battery case according to claim 8 , wherein the side portions formed on the first case and the side portions formed on the second case are formed in an unsealed state so as not to abut against each other.

10. The thickness of the movement prevention portion is The battery case according to claim 9 , which is formed to be thicker than the sealing portion and thinner than the insulation failure prevention portion.

11. The melted sealing material from the seal portion is The battery case according to claim 1 , wherein the insulation failure prevention portion protrudes.

12. An apparatus for forming a battery case of a pouch-type secondary battery in which an electrode assembly is housed, comprising: A die plate on which a pouch film is placed, a molding part is formed that is recessed or penetrated downward from the upper surface, and a groove is formed around the molding part; a stripper that presses and fixes the pouch film on an upper portion of the die plate, and has a punch hole penetrating the upper and lower surfaces at a position corresponding to the molding part, and has a rib formed around the punch hole facing the groove; a punch that is drawn into a molding portion of the die plate through the punch hole of the stripper to form a cup portion in the pouch film.

13. A method for manufacturing a pouch-type secondary battery having an electrode assembly therein, comprising: forming a battery case including a cup portion and an insulation failure prevention portion; and housing the electrode assembly in the cup portion and sealing the sealing portion of the battery case. The step of forming the battery case includes: Placing a pouch film on a die plate having a molding portion and a groove around the molding portion; a stripper having a punch hole and a rib formed around the punch hole presses and fixes the pouch film on the upper part of the die plate, and the rib is drawn into the groove to form the insulation failure prevention part in the pouch film; a punch is drawn into a molding portion of the die plate through the punch hole of the stripper to form the cup portion in the pouch film.

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