Battery cell and manufacturing method thereof

Abstract

To provide a battery cell and a manufacturing method thereof, capable of preventing turned-up of a separator during electrolyte injection and a short circuit due to the turned-up, while reducing assembling man-hours.SOLUTION: A battery cell includes: an electrode body including a positive electrode plate and a negative electrode plate; an outer can having an opening and housing the electrode body therein; a sealing plate having a terminal part insertion hole and an electrolyte injection hole and sealing the opening of the outer can; a terminal part penetrating through the terminal part insertion hole; a current collector electrically connected to the positive electrode plate or the negative electrode plate; and a resin insulator having a first portion insulating the terminal part and the sealing plate at the outside of the outer can, a second portion insulating the current collector and the sealing plate at the inside of the outer can, and a cylindrical third portion communicating with the electrolyte injection hole. The third portion of the resin insulator includes a blocking part blocking between at least a part of the electrolyte injection hole and the electrode body. The first, second and third portions of the resin insulator are molded integrally.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present technology relates to a battery cell and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 (JP 2019-129129 A) describes a battery having a cylinder that communicates with a liquid injection hole for injecting electrolyte into the battery cell housing. Here, a shielding portion is provided between the liquid injection hole and the electrode body to prevent the separator from curling up due to electrolyte injection and the associated electrical short circuit.

[0003] Patent document 2 (JP 2021-86813 A) describes a battery case member and a collector terminal that have an improved anchor effect by roughening at least a portion of the portion that comes into contact with an insulating material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-129129 A [Patent Document 2] Patent Publication No. 2021-86813 Summary of the Invention [Problem to be solved by the invention]

[0005] The provision of an insulating member having a cylindrical body increases the number of parts that constitute the battery. Also, there is a demand for reducing the number of assembly steps during battery manufacturing.

[0006] An object of the present technology is to provide a battery cell that can prevent separator curling and the associated short circuit when electrolyte is injected, while reducing assembly man-hours, and a manufacturing method thereof. [Means for solving the problem]

[0007] The present technology provides the following battery cell and method for manufacturing the same.

[0008] [1] A battery cell comprising: an electrode assembly including a positive electrode plate and a negative electrode plate; an outer can having an opening and housing the electrode assembly; a sealing plate having a terminal portion insertion hole and an electrolyte injection hole and sealing the opening of the outer can; a terminal portion that penetrates the terminal portion insertion hole; a current collector electrically connected to the positive electrode plate or the negative electrode plate; and a resin insulator having a first portion that insulates the terminal portion and the sealing plate outside the outer can, a second portion that insulates the current collector and the sealing plate inside the outer can, and a cylindrical third portion that communicates with the electrolyte injection hole, wherein the third portion of the resin insulator includes a blocking portion that blocks communication between at least a part of the electrolyte injection hole and the electrode assembly, and the first portion, second portion, and third portion of the resin insulator are integrally molded.

[0009] [2] The battery cell according to [1], in which the terminal portion and the resin insulator are integrated by insert molding.

[0010] [3] The battery cell according to [1] or [2], wherein at least a portion of the contact surface between the terminal portion or the sealing plate and the resin insulator is roughened.

[0011] [4] The battery cell according to any one of [1] to [3], wherein the interrupter portion includes a strip-shaped portion formed so as to cross the cylindrical third portion. [5] The battery cell according to [4], wherein a through hole is formed in the strip-shaped portion of the interrupter.

[0012] [6] The strip portion includes a first strip portion extending in a first direction and a second strip portion extending in a direction intersecting the first direction. Extended and a second band-shaped portion extending from the first band-shaped portion.

[0013] [7] The battery cell according to any one of [1] to [3], wherein the interrupter portion includes a portion formed in a substantially polygonal shape.

[0014] [8] A battery cell described in any one of [1] to [3], wherein the interrupting portion is formed on only one side of the center of the cylindrical third portion.

[0015] [9] A method for manufacturing a battery cell, comprising the steps of: forming an electrode body including a positive electrode plate and a negative electrode plate; electrically connecting the positive electrode plate or the negative electrode plate to a current collector; attaching a terminal portion and a resin insulator to a sealing plate having an electrolyte injection hole; connecting the current collector to the terminal portion; housing the electrode body in an outer can having an opening; sealing the opening of the outer can with the sealing plate; and injecting electrolyte into the outer can through the electrolyte injection hole, wherein the resin insulator has a first portion that insulates the terminal portion and the sealing plate on the outside of the outer can, a second portion that insulates the current collector and the sealing plate inside the outer can, and a cylindrical third portion that communicates with the electrolyte injection hole, the third portion of the resin insulator includes a blocking portion that blocks communication between at least a part of the electrolyte injection hole and the electrode body, and the first portion, second portion, and third portion of the resin insulator are integrally molded.

[0016]

[10] The method for manufacturing a battery cell according to [9], in which the terminal portion and the resin insulator are integrated by insert molding.

[0017]

[11] The method for manufacturing a battery cell according to [9] or

[10] , further comprising a step of roughening at least a portion of the contact surface between the terminal portion or the sealing plate and the resin insulator. Effect of the Invention

[0018] The number of parts and assembly steps can be reduced by integrally molding a resin insulator having a first portion that insulates the terminal portion and the sealing plate outside the exterior can, a second portion that insulates the current collector and the sealing plate inside the exterior can, and a cylindrical third portion (cylinder) that communicates with the electrolyte injection hole. The third portion includes a blocking portion that blocks the gap between at least a part of the electrolyte injection hole and the electrode body, thereby preventing the separator from curling up when the electrolyte is injected and the resulting electrical short circuit. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a perspective view showing a battery cell. [Diagram 2] FIG. 2 is a plan view of a positive electrode plate that constitutes an electrode body. [Diagram 3] FIG. 2 is a plan view of a negative electrode plate that constitutes an electrode body. [Figure 4] FIG. 2 is a plan view showing an electrode assembly consisting of a positive electrode plate and a negative electrode plate. [Diagram 5] 4A and 4B are diagrams showing a connection structure between an electrode body, a positive electrode current collecting member, and a negative electrode current collecting member. [Figure 6] FIG. 4 is a perspective view showing a state in which an electrode terminal is attached to a sealing plate. [Figure 7] FIG. 4 is a cross-sectional view showing a state in which a positive electrode terminal is attached to the sealing plate. [Figure 8] FIG. 1 is a diagram (part 1) showing an example of the shape of a blocking part located between a liquid inlet and an electrode body. [Figure 9] FIG. 2 is a diagram (part 2) showing an example of the shape of the blocking portion located between the liquid inlet and the electrode body. [Figure 10] FIG. 11 is a diagram (part 3) showing an example of the shape of the blocking part located between the liquid inlet and the electrode body. [Figure 11] FIG. 11 is a diagram (part 4) showing examples of the shape of the blocking part located between the liquid inlet and the electrode body. [Figure 12] FIG. 5 is a diagram showing an example of the shape of the blocking portion located between the liquid inlet and the electrode body (part 5). [Figure 13] FIG. 6 is a diagram showing an example of the shape of the blocking portion located between the liquid inlet and the electrode body. [Figure 14] FIG. 11 is a diagram (part 7) showing examples of the shape of the blocking portion located between the liquid inlet and the electrode body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof will not be repeated.

[0021] In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiment.

[0022] In this specification, the words "comprise", "include" and "have" are open-ended, i.e., when a certain configuration is included, other configurations may or may not be included.

[0023] Furthermore, when geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0024] In this specification, a "battery cell" can be mounted in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), etc. However, the use of the "battery cell" is not limited to being mounted in a vehicle.

[0025] Fig. 1 is a perspective view showing a battery cell 100. As shown in Fig. 1, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110 (terminal portion), a housing 120 (external can), a gas release valve 130, and a rivet 140.

[0026] The electrode terminal 110 is formed on the housing 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112 aligned along an X-axis direction (second direction) perpendicular to a Y-axis direction (first direction). The positive electrode terminal 111 and the negative electrode terminal 112 are provided apart from each other in the X-axis direction.

[0027] The housing 120 has a rectangular parallelepiped shape and forms the external appearance of the battery cell 100. The housing 120 includes a case body 120A that contains an electrode body and an electrolyte (not shown), and a sealing plate 120B that seals an opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

[0028] The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and two third side surfaces 125.

[0029] The upper surface 121 is a plane perpendicular to the Z-axis direction (third direction) perpendicular to the Y-axis direction and the X-axis direction. The electrode terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

[0030] Each of the first side surface 123 and the second side surface 124 is formed of a plane perpendicular to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the housing 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape with the X-axis direction being the long side direction and the Z-axis direction being the short side direction when viewed in the Y-axis direction.

[0031] The multiple battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the battery cells 100 adjacent to each other in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

[0032] Gas exhaust valve 130 is provided on top surface 121. When the temperature of battery cell 100 rises (thermal runaway) and the internal pressure of housing 120 exceeds a predetermined value due to gas generated inside housing 120, gas exhaust valve 130 exhausts the gas to the outside of housing 120.

[0033] The rivet 140 is attached to the sealing plate 120B of the housing 120. The rivet 140 seals an electrolyte injection hole (see FIG. 7) which will be described later.

[0034] FIG. 2 is a plan view of the positive electrode plate 200A constituting the electrode body 200. The positive electrode plate 200A has a main body 220A in which a positive electrode active material mixture layer containing a positive electrode active material (such as lithium nickel cobalt manganese composite oxide), a binder (polyvinylidene fluoride (PVdF)), and a conductive material (such as carbon material) is formed on both sides of a rectangular positive electrode core made of aluminum foil. The positive electrode core protrudes from the end side of the main body, and this protruding positive electrode core constitutes the positive electrode tab 210A. A positive electrode protective layer 230A containing alumina particles, a binder, and a conductive material is provided in a portion of the positive electrode tab 210A adjacent to the main body 220A. The positive electrode protective layer 230A has a larger electric resistance than the electric resistance of the positive electrode active material mixture layer. The positive electrode active material mixture layer does not need to contain a conductive material. The positive electrode protective layer 230A does not necessarily need to be provided.

[0035] 3 is a plan view of the negative electrode plate 200B constituting the electrode assembly 200. The negative electrode plate 200B has a main body 220B in which a negative electrode active material mixture layer is formed on both sides of a rectangular negative electrode core made of copper foil. The negative electrode core protrudes from an end side of the main body 220B, and this protruding negative electrode core constitutes the negative electrode tab 210B.

[0036] FIG. 4 is a plan view showing an electrode assembly 200 consisting of a positive electrode plate 200A and a negative electrode plate 200B. As shown in FIG. 5, the electrode assembly 200 is fabricated such that the positive electrode tabs 210A of the positive electrode plates 200A are stacked at one end, and the negative electrode tabs 210B of the negative electrode plates 200B are stacked. For example, about 50 positive electrode plates 200A and 50 negative electrode plates 200B are stacked. The positive electrode plates 200A and the negative electrode plates 200B are stacked alternately with rectangular separators made of polyolefin interposed therebetween. Note that a long separator may be used by folding it in a zigzag pattern.

[0037] Fig. 5 is a diagram showing a connection structure between the electrode body 200 and the positive and negative current collecting members 600 and 700. As shown in Fig. 5, the electrode body 200 is composed of a first electrode body element 201 (first laminate group) and a second electrode body element 202 (second laminate group). Separators are also arranged on the outer surfaces of the first electrode body element 201 and the second electrode body element 202, respectively.

[0038] The multiple positive electrode tabs 210A of the first electrode body element 201 constitute a first positive electrode tab group 211A. The multiple negative electrode tabs 210B of the first electrode body element 201 constitute a first negative electrode tab group 211B. The multiple positive electrode tabs 210A of the second electrode body element 202 constitute a second positive electrode tab group 212A. The multiple negative electrode tabs 210B of the second electrode body element 202 constitute a second negative electrode tab group 212B.

[0039] A positive electrode current collecting member 600 and a negative electrode current collecting member 700 are disposed between the first electrode body element 201 and the second electrode body element 202. The first positive electrode tab group 211A and the second positive electrode tab group 212A are welded and connected onto the positive electrode current collecting member 600 to form a welded connection portion 213. The first negative electrode tab group 211B and the second negative electrode tab group 212B are welded and connected onto the negative electrode current collecting member 700 to form the welded connection portion 213. The welded connection portion 213 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, or the like.

[0040] When manufacturing the battery cell 100, the electrode body 200 including the positive electrode plate 200A and the negative electrode plate 200B is formed, and the positive electrode plate 200A and the negative electrode plate 200B are electrically connected to the positive electrode current collector 600 and the negative electrode current collector 700 (current collectors), respectively. Next, the positive electrode terminal 111 and the negative electrode terminal 112 (terminal portion) attached to the sealing plate 120B are connected (for example, by crimping) to the positive electrode current collector 600 and the negative electrode current collector 700, respectively. In this state, the electrode body 200 is housed in the case body 120A, and the opening of the case body 120A is sealed with the sealing plate 120B.

[0041] FIG. 6 is a perspective view showing a state in which the electrode terminal 110 is attached to the sealing plate 120B, and FIG. 7 is a cross-sectional view showing the state of FIG. 6 (positive electrode terminal 111 side).

[0042] As shown in FIGS. 6 and 7, the sealing plate 120B has an electrolyte injection hole 120B1 and a terminal portion insertion hole 120B2.

[0043] An electrode terminal 110 (a positive terminal 111 is shown in FIG. 7) is inserted into the terminal insertion hole 120B2. After the opening of the case body 120A is sealed with the sealing plate 120B, an electrolyte is injected into the housing 120 through the electrolyte injection hole 120B1.

[0044] Resin insulators 800 and 900 are attached to the sealing plate 120B together with the electrode terminals 110 (positive electrode terminal 111 and negative electrode terminal 112). The positive electrode terminal 111 and the negative electrode terminal 112 may be integrated with the resin insulators 800 and 900 by insert molding.

[0045] The resin insulator 800 has a first portion 810 that insulates the positive electrode terminal 111 and the sealing plate 120B outside the housing 120, a second portion 820 that insulates the positive electrode current collecting member 600 and the sealing plate 120B inside the housing 120, and a cylindrical third portion 830 that communicates with the electrolyte injection hole 120B1.

[0046] The third portion 830 of the resin insulator 800 includes a blocking portion 830A that blocks the gap between at least a part of the electrolyte injection hole 120B1 and the electrode body 200. The first portion 810, the second portion 820, and the third portion 830 are integrally molded.

[0047] Since the third portion 830 of the resin insulator 800 includes a blocking portion 830A that blocks the gap between at least a portion of the electrolyte injection hole 120B1 and the electrode terminal 110, curling of the separator and the resulting electrical short circuit when the electrolyte is injected can be suppressed.

[0048] On the other hand, providing a cylindrical portion (corresponding to the third portion 830) that communicates with the electrolyte injection hole 120B1 can increase the number of parts that make up the battery cell 100. There is also a demand for reducing the number of assembly steps for each part during the manufacture of the battery cell 100.

[0049] In the battery cell 100 according to the present embodiment, a first portion 810 that insulates the positive terminal 111 from the sealing plate 120B outside the housing 120 and a positive current collecting member 60 0 and By integrally molding the resin insulator 800 having the second portion 820 that insulates from the sealing plate 120B and the cylindrical third portion 830 that communicates with the electrolyte pouring hole 120B1, it is possible to reduce the number of parts of the battery cell 100 and the number of steps required to assemble each part. As a result, it is possible to manufacture the battery cell 100 at low cost while suppressing the curling of the separator when the electrolyte is poured.

[0050] At least a part of the contact surfaces of the electrode terminal 110 and the sealing plate 120B with the resin insulators 800, 900 may be roughened. When the surfaces are roughened as described above, the adhesion between the electrode terminal 110 and the sealing plate 120B and the resin insulators 800, 900 can be improved due to an anchor effect.

[0051] The structures of the electrode terminal 110, sealing plate 120B and resin insulator 800 are not limited to those shown in Figs. 6 and 7, and for example, the electrode terminal 110 may have a current interrupt device (CID).

[0052] 6 and 7, the resin insulator 800 on the positive terminal 111 side and the resin insulator 900 on the negative terminal 112 side are formed separately, and the resin insulator on the positive terminal 111 side is provided with a cylindrical third portion 830 communicating with the electrolyte injection hole 120B1, but the scope of the present technology is not limited thereto. For example, the resin insulator 900 on the negative terminal 112 side may be provided with a cylindrical portion (corresponding to the third portion 830) communicating with the electrolyte injection hole 120B1, or the resin insulators 800 and 900 may be provided as a single member.

[0053] 8 to 14 are diagrams showing examples of the shape of the blocking portion 830A. Note that the shapes of the blocking portion 830A shown in Figs. 8 to 14 are merely examples, and the scope of the present technology is not limited to these.

[0054] 8 and 9, blocking portion 830A is made of a strip-shaped portion formed so as to cross cylindrical third portion 830. In the example of Fig. 8, the strip-shaped portion extends in the X-axis direction, and in the example of Fig. 9, the strip-shaped portion extends in the Y-axis direction.

[0055] The strip portion may extend in a diagonal direction intersecting the X-axis direction and the Y-axis direction. The width of the strip portion may be changed as appropriate. The strip portion may be formed in a plurality of separate parts.

[0056] In the examples of FIGS. 8 and 9, the band-shaped portion is formed in a region including the center of the cylindrical third portion 830, but the scope of the present technology is not limited to this.

[0057] As shown in the example of FIG. 10, the strip portion includes a first strip portion extending in the Y-axis direction and a second strip portion extending in the X-axis direction. Extended10, the first band-shaped portion and the second band-shaped portion are shown to be substantially perpendicular to each other in a cross shape, but the first band-shaped portion and the second band-shaped portion may cross each other obliquely.

[0058] As in the example of Fig. 11, a through hole 831 may be formed in the band-shaped portion. The position, shape, and size of the through hole 831 may be changed as appropriate. A plurality of through holes 831 may be provided as shown in Fig. 11, or only one through hole 831 may be provided.

[0059] 12, blocking portion 830A may be rectangular (quadrilateral). Furthermore, the cylindrical shape of third portion 830 of resin insulator 800 is not limited to a circular shape, and may be a quadrilateral shape as in FIG.

[0060] As shown in the example of Fig. 13, the blocking portion 830A may be formed in a substantially polygonal shape including shapes other than a rectangle. A substantially polygonal shape does not mean a perfect polygon, but includes shapes in which corners are rounded or chamfered, for example. Also, as shown in the example of Fig. 13 (regular hexagonal shape), the blocking portion 830A is not limited to a regular polygon.

[0061] 14, blocking portion 830A may be formed only on one side with respect to the center of cylindrical third portion 830. In the example of Fig. 14, blocking portion 830A has a substantially crescent shape, but even when blocking portion 830A is formed only on one side with respect to the center of cylindrical third portion 830, the shape of blocking portion 830A can be appropriately changed.

[0062] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0063] 100 battery cell, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 housing, 120A case body, 120B1 electrolyte injection hole, 120B2 terminal insertion hole, 120B sealing plate, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 130 gas exhaust valve, 140 rivet, 200 electrode body, 200A positive electrode plate, 200B negative electrode plate, 201 first electrode body element, 202 second electrode body element, 210A positive electrode tab, 210B negative electrode tab, 211A first positive electrode tab group, 211B first negative electrode tab group, 212A second positive electrode tab group, 212B second negative electrode tab group, 213 Welded connection portion, 220A, 220B main body portion, 230A positive electrode protective layer, 600 positive electrode current collecting member, 700 negative electrode current collecting member, 800 resin insulator, 810 first portion, 820 second portion, 830 third portion, 830A interrupter portion, 831 through hole, 900 resin insulator.

Claims

1. An electrode assembly including a positive electrode plate and a negative electrode plate; an exterior can having an opening and housing the electrode assembly; a sealing plate having a terminal portion insertion hole and an electrolyte injection hole, and sealing the opening of the exterior can; A terminal portion that passes through the terminal portion insertion hole; a current collector electrically connected to the positive electrode plate or the negative electrode plate; a resin insulator having a first portion that insulates the terminal portion and the sealing plate outside the exterior can, a second portion that insulates the current collector and the sealing plate inside the exterior can, and a cylindrical third portion that communicates with the electrolyte injection hole, the terminal portion is inserted into the terminal portion insertion hole from the inside of the exterior can, the third portion of the resin insulator includes a blocking portion that blocks a gap between at least a portion of the electrolyte injection hole and the electrode body, the first portion, the second portion, and the third portion of the resin insulator are integrally molded; The terminal portion and the resin insulator are integrated by insert molding, At least a portion of the contact surface between the terminal portion or the sealing plate and the resin insulator is roughened.

2. The battery cell according to claim 1 , wherein the interrupting portion includes a band-shaped portion formed so as to cross the cylindrical third portion.

3. The battery cell according to claim 2 , wherein a through hole is formed in the strip-shaped portion of the cutoff portion.

4. The battery cell according to claim 2 , wherein the strip portion includes a first strip portion extending in a first direction and a second strip portion extending in a direction intersecting the first direction.

5. The battery cell according to claim 1 , wherein the cutoff portion includes a portion formed in a substantially polygonal shape.

6. The battery cell according to claim 1 , wherein the interrupting portion is formed only on one side of a center of the cylindrical third portion.

7. forming an electrode assembly including a positive electrode plate and a negative electrode plate; a step of electrically connecting the positive electrode plate or the negative electrode plate to a current collector; a step of attaching a terminal portion and a resin insulator to a sealing plate having an electrolyte injection hole; a step of connecting the current collector and the terminal portion; A step of housing the electrode assembly in an exterior can having an opening; sealing the opening of the exterior can with the sealing plate; injecting an electrolyte into the exterior can through the electrolyte injection hole; the resin insulator has a first portion that insulates the terminal portion and the sealing plate outside the exterior can, a second portion that insulates the current collector and the sealing plate inside the exterior can, and a cylindrical third portion that communicates with the electrolyte injection hole, the terminal portion is inserted into a terminal portion insertion hole provided in the sealing plate from the inside of the exterior can, the third portion of the resin insulator includes a blocking portion that blocks a gap between at least a portion of the electrolyte injection hole and the electrode body, the first portion, the second portion, and the third portion of the resin insulator are integrally molded; The terminal portion and the resin insulator are integrated by insert molding, The method for manufacturing a battery cell further comprises a step of roughening at least a portion of a contact surface between the terminal portion or the sealing plate and the resin insulator.

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