Secondary battery and method for manufacturing same

Abstract

According to exemplary embodiments of the present invention, a secondary battery is provided. The secondary battery may comprise: an electrode assembly in which a positive electrode and a negative electrode are stacked in a first direction; a case comprising an accommodation part for accommodating the electrode assembly; an electrode terminal protruding from a first edge part of the case; and a coating layer on the first edge part, wherein the first edge part comprises a first surface and a second surface opposite to each other in the first direction, the coating layer is disposed on the first surface, the coating layer comprises a thermal resin, and the coating layer overlaps the electrode assembly and does not overlap the electrode terminal.

Description

Secondary battery and method of manufacturing the same

[0001] The present invention relates to a secondary battery and a method for manufacturing the same. Specifically, the present invention relates to a pouch-type secondary battery and a method for manufacturing the same.

[0002] This application claims the benefit of Korean application No. 10-2024-0127574, filed on September 20, 2024, which is incorporated herein by reference in its entirety.

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for various wireless devices such as handsets, laptops, and cordless vacuum cleaners. Recently, as the manufacturing cost per unit capacity of secondary batteries has decreased dramatically due to improved energy density and economies of scale, and as the driving range of BEVs (battery electric vehicles) has increased to a level equivalent to that of fuel vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0004] The trend in the technological development of rechargeable batteries for mobility is the improvement of energy density and safety. The safety of rechargeable batteries is critical as it is directly linked to the lives of passengers. The safety of rechargeable batteries can be achieved through mechanical robustness, the reliability of electrical insulation, and the delay of heat transfer in the event of a thermal runaway event.

[0005] The problem that the technical concept of the present invention aims to solve is to provide a secondary battery with improved performance and reliability.

[0006] The problem that the technical concept of the present invention aims to solve is to provide a secondary battery with improved safety.

[0007] The problem that the technical concept of the present invention aims to solve is to provide a method for manufacturing a secondary battery with improved safety.

[0008] The problem that the technical concept of the present invention aims to solve is to provide a method for manufacturing a secondary battery with improved performance and reliability.

[0009] According to exemplary embodiments of the present invention for solving the above-described problem, a secondary battery is provided. The secondary battery comprises: an electrode assembly in which a positive electrode and a negative electrode are stacked in a first direction; a case including a receiving portion for receiving the electrode assembly; an electrode terminal protruding from a first edge portion of the case; and a coating layer on the first edge portion, wherein the first edge portion includes a first surface and a second surface opposite to the first direction, and the coating layer is disposed on the first surface, and the coating layer includes a thermal resin, and the coating layer may overlap with the electrode assembly and not overlap with the electrode terminal.

[0010] The electrode terminal may protrude in a second direction intersecting the first direction, and the coating layer may not overlap with the electrode terminal in the second direction.

[0011] The above case includes a first corner portion that is part of the first edge portion and overlaps the electrode assembly in the second direction, and the coating layer may be disposed on the first corner portion.

[0012] The highest vertical level of the coating layer in the first direction may be less than or equal to the highest vertical level of the receiving portion in the first direction.

[0013] The coating layer may be in contact with the first surface of the first edge portion, spaced apart from the second surface with the first surface in between, and may not be in contact with the second surface.

[0014] The above case further includes the first edge portion, the second edge portion, and the third edge portion adjacent to the first side portion, the second side portion, and the third side portion, respectively, the first side portion and the second side portion extend in a second direction intersecting the first direction, the third side portion and the fourth side portion of the receiving portion extend in a third direction intersecting the first direction and the second direction, the first edge portion includes a first corner portion adjacent to the fourth side portion, and the coating layer may be disposed on the first corner portion.

[0015] The second edge portion includes a second corner portion adjacent to the fourth side portion, and the coating layer may be further disposed on the second corner portion.

[0016] The first edge portion extends in a second direction intersecting the first direction, and the case further includes a sealing portion that seals the first edge portion, and the coating layer may be disposed between the sealing portion and the third direction intersecting the first direction and the second direction of the receiving portion.

[0017] According to exemplary embodiments of the present invention for solving the above-described problem, a method for manufacturing a secondary battery is provided. The method for manufacturing a secondary battery comprises the steps of assembling an electrode assembly; receiving the electrode assembly in a case; sealing the case; forming a coating layer on a first surface of an edge portion; and injecting an electrolyte, wherein the coating layer comprises a thermal resin, the edge portion comprises a corner portion that overlaps with the electrode assembly of the case, and the coating layer may be formed on the corner portion.

[0018] The coating layer is formed on the first surface of the edge portion, and the coating layer may not be formed on the second surface opposite to the first surface in the first direction.

[0019] The electrode assembly is stacked in a first direction, and the corner portion can overlap the electrode assembly in a second direction that intersects the first direction.

[0020] After the step of injecting the above electrolyte, the method may further include a pre-aging step; an activation step; and an aging step.

[0021] According to exemplary embodiments of the present invention, a secondary battery may include a coating layer on the edge portion of a case. The coating layer provides rigidity to the case, thereby preventing the case from being damaged by impact during the process of providing the secondary battery. By doing so, defects that may occur during the manufacturing process of the secondary battery can be reduced.

[0022] According to exemplary embodiments of the present invention, a secondary battery with improved safety can be provided.

[0023] According to exemplary embodiments of the present invention, a secondary battery with improved performance and reliability can be provided.

[0024] According to exemplary embodiments of the present invention, a method for manufacturing a secondary battery with improved safety can be provided.

[0025] According to exemplary embodiments of the present invention, a method for manufacturing a secondary battery with improved performance and reliability can be provided.

[0026] The effects obtainable from the exemplary embodiments of the present invention are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects resulting from the implementation of the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0027] FIG. 1 is a drawing of a secondary battery according to embodiments of the technical concept of the present invention.

[0028] FIG. 2 is a drawing of a secondary battery according to embodiments of the technical concept of the present invention.

[0029] FIG. 3 is an enlarged view of a secondary battery according to embodiments of the technical concept of the present invention.

[0030] FIG. 4 is an enlarged view of a secondary battery according to embodiments of the technical concept of the present invention.

[0031] FIG. 5 is a flowchart illustrating a method for manufacturing a secondary battery according to embodiments based on the technical concept of the present invention.

[0032] FIG. 6 is a flowchart illustrating a method for manufacturing a secondary battery according to embodiments based on the technical concept of the present invention.

[0033] FIG. 7 is a drawing for explaining a method for manufacturing a secondary battery according to embodiments based on the technical concept of the present invention.

[0034] FIG. 8 is a drawing for explaining a method for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0035] FIG. 9 is a drawing for explaining a method for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0036] FIG. 10 is a drawing for explaining a method for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0038] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0039] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0040] Since embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically depicted for clearer explanation. Accordingly, the size or proportion of each component does not entirely reflect the actual size or proportion.

[0041]

[0042] (1st embodiment)

[0043] FIG. 1 is a drawing of a secondary battery (100) according to embodiments of the technical concept of the present invention.

[0044] FIG. 2 is a drawing of a secondary battery (100) according to embodiments of the technical concept of the present invention.

[0045] FIG. 3 is an enlarged view of a secondary battery (100) according to embodiments of the technical concept of the present invention. Specifically, FIG. 3 is an enlarged view of the EX1 region of FIG. 1.

[0046] FIG. 4 is an enlarged view of a secondary battery (100) according to embodiments of the technical concept of the present invention. Specifically, FIG. 4 is an enlarged view of the EX2 region of FIG. 2.

[0047]

[0048] Referring to FIGS. 1 and 2, the secondary battery (100) may include an electrode assembly (100EA), a case (100C), a positive terminal (100P), and a negative terminal (100N). The secondary battery (100) may further include an electrolyte.

[0049] In the embodiments, the secondary battery (100) may include a pouch-type secondary battery. The electrode assembly of the pouch-type secondary battery may be embedded in a pouch case comprising an aluminum laminate sheet. Hereinafter, the technical concept of the present invention will be explained based on an example in which the secondary battery (100) is a pouch-type secondary battery.

[0050] The electrode assembly (100EA) may include an anode, a cathode, and a separator interposed between the anode and the cathode. The electrode assembly (100EA) may be either a jelly-roll type or a stack type. A jelly-roll type electrode assembly (100EA) may include a wound structure of an anode, a cathode, and a separator interposed between them. A stack type electrode assembly (100EA) may include a plurality of anodes, a plurality of cathodes, and a plurality of separators interposed between them that are sequentially stacked.

[0051] In a stack-type electrode assembly (100EA), a plurality of positive electrodes and a plurality of negative electrodes can be arranged in a first direction (D1). In a stack-type electrode assembly (100EA), a plurality of positive electrodes and a plurality of negative electrodes can be stacked in a first direction (D1).

[0052] Each of the plurality of positives of the electrode assembly (100EA) may include a positive tab (not shown). The positive tab of each of the plurality of positives of the electrode assembly (100EA) may be short-circuited with a positive terminal (100P). The positive tab of each of the plurality of positives of the electrode assembly (100EA) may be welded with a positive terminal (100P).

[0053] Each of the plurality of cathodes of the electrode assembly (100EA) may include a cathode tab (not shown). Each of the cathode tabs of the plurality of cathodes of the electrode assembly (100EA) may be short-circuited with a cathode terminal (100N). Each of the cathode tabs of the plurality of cathodes of the electrode assembly (100EA) may be welded with a cathode terminal (100N).

[0054] The case (100C) may include an inner resin layer, a metal layer, and an outer resin layer. An adhesive and an anti-corrosion layer may be further provided between the inner resin layer and the metal layer and between the outer resin layer and the metal layer.

[0055] The inner resin layer may have heat-sealability and may be referred to as a sealant layer. The inner resin layer enables sealing of the case (100C). The inner resin layer may include a polyolefin-based resin, such as polypropylene (PP) and polyethylene (PE), for example. The metal layer may include any one of an alloy of iron, carbon, chromium, and manganese, an alloy of iron, chromium, and nickel, and aluminum. The metal layer may be a gas barrier. The metal layer may block the entry and exit of gas through the case (100C). The outer resin layer may be a surface protection layer. The outer resin layer may include a material having wear resistance and heat resistance, such as nylon resin.

[0056] The positive terminal (100P) and the negative terminal (100N) may protrude outside the case (100C). The positive terminal (100P) and the negative terminal (100N) may protrude from the case (100C) in a second direction (D2). Accordingly, the resulting voltage and current of the secondary battery (100) can be output through the positive terminal (100P) and the negative terminal (100N). The positive terminal (100P) may be a positive lead. The negative terminal (100N) may be a negative lead.

[0057] Hereinafter, the technical concept of the present invention will be explained with reference to an example in which each of the plurality of secondary batteries (100) is a bidirectional cell in which the positive terminal (100P) and the negative terminal (100N) of the secondary battery (100) are formed on opposite sides of the case (100C). A person skilled in the art will be able to easily reach a unidirectional cell for each of the plurality of secondary batteries (100) based on what is described herein. The positive terminal (100P) and the negative terminal (100N) may be spaced apart in a second direction (D2). The second direction (D2) may be substantially parallel to each of the plurality of positives of the electrode assembly (100EA) and each of the plurality of negatives of the electrode assembly (100EA).

[0058] In the embodiments, the case (100C) may include a receiving portion (100R) that accommodates an electrode assembly (100EA) and an edge portion that surrounds the receiving portion (100R). The edge portion may surround the receiving portion (100R) in a U-shape. The edge portion may be U-shaped.

[0059] Specifically, the positive terminal (100P) and the negative terminal (100N) may protrude from the edge portion. For example, the positive terminal (100P) and the negative terminal (100N) may protrude from the edge portion in a second direction (D2). For example, the positive terminal (100P) may protrude from the first edge portion (121) in a second direction (D2). For example, the negative terminal (100N) may protrude from the second edge portion (122) in a second direction (D2).

[0060]

[0061] In the embodiments, a coating layer (130) may be disposed on the first edge portion (121). Specifically, as illustrated in FIG. 2, the first edge portion (121) may include a first surface (121_1) and a second surface (121_2) opposite in the first direction (D1). The coating layer (130) may be disposed on the first surface (121_1) of the first edge portion (121). The coating layer (130) may be in contact with the first surface (121_1). For example, the coating layer (130) may be spaced apart from the second surface (121_2) with the first surface (121_1) of the first edge portion (121) in between. The coating layer (130) may not be in contact with the second surface (121_2).

[0062] The coating layer (130) may be placed on a local area of ​​the first edge portion (121). For example, the coating layer (130) may be placed locally on a portion of the area that overlaps with the electrode assembly (100EA) of the first edge portion (121).

[0063] The coating layer (130) may include a thermal resin. For example, the coating layer (130) may be formed by applying a thermal resin to a local area of ​​the first surface (121_1) of the first edge portion (121) and then curing it.

[0064] The coating layer (130) may overlap with the electrode assembly (100EA) in a second direction (D2). The coating layer (130) may not overlap with the electrode terminal in a second direction (D2). For example, the coating layer (130) may not overlap with the positive terminal (100P) in a second direction (D2).

[0065] The case (100C) may include a corner portion. Specifically, the case (100C) may include a first corner portion (121C) which is part of the first edge portion (121). Among the four corner portions of the case (100C) as exemplified in FIG. 1, the corner portion that is part of the first edge portion (121) and overlaps with the electrode assembly (100EA) in the second direction (D2) may be referred to as the first corner portion (121C).

[0066] Specifically, the first side (111), the second side (112), and the third side (113) of the receiving portion (100R) can each be surrounded by the first edge portion (121), the second edge portion (122), and the third edge portion (123).

[0067] For example, the first side (111) and the first edge (121) extend in the third direction (D3), and the first edge (121) may refer to a portion adjacent to the first side (111). The third direction (D3) may intersect the first direction (D1) and the second direction (D3). For example, the second side (112) and the second edge (122) extend in the third direction (D3), and the second edge (122) may refer to a portion adjacent to the second side (112). The first edge (121) and the second edge (122) may be spaced apart with the receiving portion (100R) in between. For example, the third side (113) and the third edge (123) extend in the second direction (D2), and the third edge (123) may refer to a portion adjacent to the third side (113). The fourth side (114) of the receiving portion may not be surrounded by the edge portions. The first edge (121), the second edge (122), and the third edge (123) may form a U-shape.

[0068] Referring to FIG. 3, the first corner portion (121C) may be adjacent to the fourth side portion (114). The first edge portion (121) may extend in a direction intersecting the fourth side portion (114), and a portion of the first edge portion (121) adjacent to the fourth side portion (114) may be referred to as the first corner portion (121C). Specifically, a portion of the first edge portion (121) adjacent to the fourth side portion (114) and not overlapping with the positive terminal (100P) may be referred to as the first corner portion (121C). For example, a corner portion that is part of the first edge portion (121) of the case (100C) and adjacent to the fourth side portion (114) may be referred to as the first corner portion (121C).

[0069] A coating layer (130) may be disposed on the first corner portion (121C). For example, a coating layer (130) may be disposed on one side of the first corner portion (121C).

[0070] Referring again to FIG. 1, the second corner portion (122C) may be adjacent to the fourth side portion (114). The second edge portion (122) may extend in a direction intersecting the fourth side portion (114), and a portion of the second edge portion (122) adjacent to the fourth side portion (114) may be referred to as the first corner portion (121C). Specifically, a portion of the second edge portion (122) adjacent to the fourth side portion (114) and not overlapping with the negative terminal (100N) may be referred to as the second corner portion (122C). For example, a corner portion that is part of the second edge portion (122) of the case (100C) and adjacent to the fourth side portion (114) may be referred to as the second corner portion (122C).

[0071] A coating layer (130) may be further disposed on the second corner portion (122C). For example, a coating layer (130) may be further disposed on one side of the second corner portion (122C).

[0072]

[0073] Referring together with FIG. 4, the highest vertical level of the coating layer (130) may be equal to or lower than the highest vertical level of the receiving portion (100R). In this specification, a vertical level may mean a level in the + D1 direction. In this specification, a higher vertical level may mean being located at a higher level in the + D1 direction. In this specification, the highest vertical level of a component may mean the vertical level at the point where the vertical level of the component is highest.

[0074] Specifically, the highest vertical level of the coating layer (130) may be the first level (LV1). For example, among the vertical levels of the coating layer (130), the highest vertical level may be the first level (LV1). For example, the vertical level of the top of the coating layer (130) may be the first level (LV1).

[0075] Specifically, the highest vertical level of the receiving section (100R) may be the second level (LV2). For example, among the vertical levels of the receiving section (100R), the highest vertical level may be the second level (LV2). For example, the vertical level of the upper surface of the receiving section (100R) may be the second level (LV2). The second level (LV2) may be higher than the first level (LV1).

[0076]

[0077] Referring again to FIGS. 1 and FIGS. 2, the case (100C) may further include a sealing portion that seals the edge portion.

[0078] Specifically, the first sealing portion (121S) can seal the first edge portion (121). The first sealing portion (121S) can extend in a third direction (D3). The first sealing portion (121S) can seal a portion of the first edge portion (121) to seal the case (100C). The first sealing portion (121S) can be spaced apart from the receiving portion (100R) with the remaining portion of the first edge portion (121) in between.

[0079] Likewise, the second sealing portion (122S) can seal the second edge portion (122). The second sealing portion (122S) can extend in a third direction (D3). The second sealing portion (122S) can seal a portion of the second edge portion (122) to seal the case (100C). The second sealing portion (122S) can be spaced apart from the receiving portion (100R) with the remaining portion of the second edge portion (122) in between.

[0080] The third edge portion (123) can be sealed by the third sealing portion (123S). The third sealing portion (123S) can extend in the second direction (D2). The third sealing portion (123S) can seal a portion of the third edge portion (123) to seal the case (100C). The third sealing portion (123S) can be spaced apart from the receiving portion (100R) with the remaining portion of the third edge portion (123) in between.

[0081] In the embodiments, the coating layer (130) may be disposed on the first edge portion (121) on an area where the first sealing portion (121S) is not formed. The coating layer (130) may be disposed between the receiving portion (100R) and the first sealing portion (121S). The coating layer (130) may be disposed between the first side portion (111) of the receiving portion (100R) and the first sealing portion (121S). The coating layer (130) may be disposed between the receiving portion (100R) and the first sealing portion (121S) in the second direction (D2). The coating layer (130) may not overlap the first sealing portion (121S) in the first direction (D1).

[0082] Likewise, the coating layer (130) may be disposed on the second edge portion (122) in an area where the second sealing portion (122S) is not formed. The coating layer (130) may be disposed between the receiving portion (100R) and the second sealing portion (122S). The coating layer (130) may be disposed between the second side portion (112) of the receiving portion (100R) and the second sealing portion (122S). The coating layer (130) may be disposed between the receiving portion (100R) and the second sealing portion (122S) in the second direction (D2). The coating layer (130) may not overlap the second sealing portion (122S) in the first direction (D1).

[0083]

[0084] The secondary battery (100) described with reference to FIGS. 1 to 4 may include a coating layer (130) on the edge portion of a case (100C). The coating layer (130) may provide rigidity to the case (100C). By doing so, it is possible to prevent the case (100C) from being damaged by impact during the process of manufacturing the secondary battery (100). That is, defects that may occur during the manufacturing process of the secondary battery (100) can be reduced. By doing so, the performance and reliability of the secondary battery (100) are improved, and safety can be enhanced.

[0085] According to embodiments of the technical concept of the present invention, a secondary battery (100) with improved performance and reliability can be provided.

[0086] According to embodiments of the technical concept of the present invention, a secondary battery (100) with improved safety can be provided.

[0087]

[0088] (2nd Example)

[0089] FIG. 5 is a flowchart showing a method (S100) for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0090] FIG. 6 is a flowchart showing a method (S110) for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0091] FIG. 7 is a drawing for explaining a method (S110) for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0092] FIG. 8 is a drawing for explaining a method (S110) for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0093] FIG. 9 is a drawing for explaining a method (S110) for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0094] FIG. 10 is a drawing for explaining a method (S110) for manufacturing a secondary battery according to embodiments of the technical concept of the present invention.

[0095]

[0096] Referring to FIG. 5, a method (S100) for manufacturing a secondary battery may be provided.

[0097] First, a step (S110) of assembling battery cells can be performed.

[0098] Specifically, the battery cell may include an electrode assembly and electrode terminals. The electrode terminals may include, for example, a positive terminal and / or a negative terminal.

[0099] In the step of assembling battery cells, an electrode process including a mixing process, a coating process, a roll pressing process, an optional slitting process, and a notching process may be performed. Subsequently, a process of embedding the electrode assembly in a case may be performed.

[0100] Next, a step (S120) of injecting the electrolyte may be performed. The electrolyte may be injected into the case.

[0101] Next, a pre-aging step (S130) may be performed while waiting for the electrolyte to be impregnated into the battery cell. Pre-aging may be performed prior to charging or discharging the battery cell in the process of activating the battery cell.

[0102] The key to the pre-aging step (S130) is to evenly disperse the electrolyte within the pouch cell so that the electrolyte permeates both the positive and negative electrodes evenly. The mobility of lithium ions can be improved by the pre-aging step (S130). The pre-aging step (S130) is a step that completes the electrical connection between the positive and negative electrodes before proceeding to the subsequent activation step (S140).

[0103] Next, an activation step (S140) for charging or discharging the battery cell may be performed.

[0104] While the battery cell is being charged or discharged, the battery cell can be pressurized by a pressurizing jig. Pressurizing the battery cell can prevent gas trapping and lithium plating, and can improve the uniformity of the Solid Electrolyte Interphase (SEI) film. A battery cell containing a uniform SEI film can have a relatively short charge or discharge time.

[0105] A SEI film can form on the surface of the negative electrode due to the initial charging. SEI is a thin film that forms on the surface of the negative electrode material when a battery cell is charged for the first time after manufacturing. When a battery cell is charged, lithium ions within the cell move to the negative electrode; during this process, a chemical reaction occurs when materials in the electrolyte undergo electrolysis for the first time, which can lead to the formation of an SEI film on the surface of the negative electrode. SEI can act as a type of separator. SEI can prevent additional decomposition reactions of the electrolyte during the process of lithium ions moving from the positive electrode to the negative electrode for battery charging.

[0106] Next, a step (S150) of aging the battery cell may be performed. In the aging step (S150), the battery cell may be stored at room temperature for a predetermined period of time so that the charged or discharged battery cell is stabilized.

[0107] Next, a degassing step (S160) may be performed. For example, the gas pocket portion (100G, see FIG. 10) may be removed to remove the gas generated as a by-reaction of the electrolyte during the preceding activation step (S140).

[0108]

[0109] Referring to FIG. 6, a method (S110) for manufacturing a secondary battery may be provided. The method (S100) for manufacturing a secondary battery described with reference to FIG. 5 may include the method (S110) for manufacturing a secondary battery of FIG. 6. For example, the step (S110) of assembling a battery cell of FIG. 5 may include the method (S110) for manufacturing a secondary battery of FIG. 6.

[0110] First, a step (S111) of assembling an electrode assembly may be performed. Specifically, an electrode assembly (100EA) as described with reference to FIGS. 1 and FIGS. 2 may be assembled. For example, a stack-type electrode assembly (100EA) may be assembled by stacking a plurality of positive electrodes and a plurality of negative electrodes in a first direction (D1).

[0111] Next, a step (S112) of accommodating an electrode assembly in a case may be performed. Specifically, an electrode assembly (100EA) may be accommodated in a case (100C) as described with reference to FIGS. 1 and 2.

[0112] Referring together with FIG. 7, a case (100C) can be manufactured. The case (100C) can be provided by joining a first case (100C1) and a second case (100C2). The first case (100C1) may include a first receiving portion (100R1). The first receiving portion (100R1) is a part of the first case (100C1) formed into a bowl shape for receiving an electrode assembly (100EA). The second case (100C2) may include a second receiving portion (100R2). The second receiving portion (100R2) is a part of the second case (100C2) formed into a bowl shape for receiving an electrode assembly (100EA). The first receiving portion (100R1) and the second receiving portion (100R2) may be formed by a pouch forming process. The first receiving section (100R1) and the second receiving section (100R2) can constitute the receiving section (100R).

[0113] The first case (100C1) and the second case (100C2) can be formed integrally. An electrode assembly (100EA) can be accommodated in the receiving portion (100R) of the case (100C). For example, the boundary lines of the first case (100C1) and the second case (100C2) can be folded so that the first receiving portion (100R1) and the second receiving portion (100R2) overlap in the first direction (D1), and the first case (100C1) and the second case (100C2) can be joined.

[0114] Referring together with FIG. 8, an electrode assembly (100EA) may be accommodated in a case (100C) comprising a receiving portion (100R) and a gas pocket portion (100G). The case (100C) may include a first edge portion (121) and a second edge portion (122). The first edge portion (121) and the second edge portion (122) may be located on the side of the receiving portion (100R). The first edge portion (121) and the second edge portion (122) may include a portion that overlaps with the receiving portion (100R) in a second direction (D2). The first edge portion (121) and the second edge portion (122) may extend in a third direction (D3). A positive terminal (100P) and a negative terminal (100N) may protrude from the case (100C).

[0115] Next, a step of sealing the case (S113) can be performed.

[0116] Specifically, with reference to FIG. 9, a first sealing portion (121S) and a second sealing portion (122S) can be formed. For example, the first sealing portion (121S) can be formed by sealing the first edge portion (121). For example, the second sealing portion (122S) can be formed by sealing the second edge portion (122).

[0117] Next, a step (S114) of forming a coating layer on the first surface of the edge portion may be performed.

[0118] Specifically, referring to FIG. 10, a coating layer (130) can be formed on the corner portion of the case (100C). For example, as described with reference to FIG. 1, a coating layer (130) can be formed on a corner portion that overlaps with the electrode assembly (100EA) in the second direction (D2) and does not overlap with the electrode terminal in the second direction (D2). For example, as described with reference to FIG. 2, a coating layer (130) can be formed on the first surface (121_1) of the first edge portion (121). For example, a coating layer (130) can be formed on the first surface of the second edge portion (122).

[0119]

[0120] The method for manufacturing a secondary battery (S100, S110) described with reference to FIGS. 5 to 10 may include the step (S114) of forming a coating layer on a first surface of an edge portion. As described above, the coating layer (130) can provide rigidity to the case (100C). By doing so, damage and defects to the case (100C) that may occur in subsequent processes can be prevented. That is, the performance and reliability of the secondary battery (100) are improved, and safety can be enhanced.

[0121] According to embodiments of the technical concept of the present invention, a method (S100, S110) for manufacturing a secondary battery with improved performance and reliability may be provided.

[0122] According to embodiments of the technical concept of the present invention, a method (S100, S110) for manufacturing a secondary battery with improved safety can be provided.

[0123]

[0124] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

Claims

1. An electrode assembly in which an anode and a cathode are stacked in a first direction; A case including a receiving portion for accommodating the above electrode assembly; An electrode terminal protruding from the first edge portion of the above case; and It includes a coating layer on the first edge portion, and The first edge portion includes a first surface and a second surface opposite to the first direction, and The above coating layer is disposed on the first surface, and The above coating layer comprises a thermal resin, and A secondary battery in which the coating layer overlaps with the electrode assembly and does not overlap with the electrode terminal.

2. In Paragraph 1, The electrode terminal protrudes in a second direction intersecting the first direction, and A secondary battery in which the coating layer does not overlap with the electrode terminal in the second direction.

3. In Paragraph 2, The above case includes a first corner portion that is part of the first edge portion and overlaps with the electrode assembly in the second direction, and The above coating layer is disposed on the first corner portion of the secondary battery.

4. In Paragraph 1, A secondary battery in which the highest vertical level in the first direction of the coating layer is less than or equal to the highest vertical level in the first direction of the receiving portion.

5. In Paragraph 1, A secondary battery in which the coating layer contacts the first surface of the first edge portion, is spaced apart from the second surface with the first surface in between, and does not contact the second surface.

6. In Paragraph 1, The above case further includes the first edge portion, the second edge portion, and the third edge portion adjacent to the first side portion, the second side portion, and the third side portion of the receiving portion, respectively, and The first side and the second side extend in a second direction that intersects the first direction, and The third side and the fourth side of the receiving portion extend in a third direction that intersects the first direction and the second direction, and The first edge portion includes a first corner portion adjacent to the fourth side portion, and The above coating layer is disposed on the first corner portion of the secondary battery.

7. In Paragraph 6, The second edge portion includes a second corner portion adjacent to the fourth side portion, and The above coating layer is further disposed on the second corner portion of the secondary battery.

8. In Paragraph 1, The first edge portion extends in a second direction intersecting the first direction, and The above case further includes a sealing portion that seals the first edge portion, and A secondary battery, wherein the coating layer is disposed between the sealing portion and the receiving portion in a third direction intersecting the first direction and the second direction.

9. Step of assembling the electrode assembly; A step of accommodating the electrode assembly in a case; A step of sealing the above case; A step of forming a coating layer on a first surface of an edge portion; and It includes the step of injecting an electrolyte, The above coating layer comprises a thermal resin, and The above edge portion includes a corner portion that overlaps with the electrode assembly of the above case, and A method for manufacturing a secondary battery, wherein the coating layer is formed on the corner portion.

10. In Paragraph 9, The coating layer is formed on the first surface of the edge portion, and A method for manufacturing a secondary battery, wherein the coating layer is not formed on a second surface opposite to the first surface and the first direction.

11. In Paragraph 9, The above electrode assembly is stacked in a first direction, and A method for manufacturing a secondary battery, wherein the above corner portion overlaps the above electrode assembly and the second direction intersecting the first direction.

12. In Paragraph 9, After the step of injecting the above electrolyte, Pre-aging stage; Activation step; and A method for manufacturing a secondary battery, further comprising an aging step.

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