Secondary battery and battery pack, and method for manufacturing the same

Abstract

The present application provides a technology capable of more stably joining an external conductive member and a bus bar. The manufacturing method of a secondary battery disclosed herein has: a mounting step of mounting a terminal (30) to a battery case (10); a disposition step of disposing a part of the terminal (30) mounted to the battery case (10) into a through-hole (35h) of an external conductive member (35); a covering step of covering at least a part of an upper surface (35u) of the external conductive member (35) with a cover member (2) after the disposition step; and a joining step of joining the external conductive member (35) and the terminal (30) by irradiation of energy rays after the covering step. The external conductive member (35) has a recessed portion (35a) recessed from the upper surface (35u) around the through-hole (35h). In the joining step, the external conductive member (35) and the terminal (30) are joined in a state where an edge portion of the cover member (2) is disposed between a joining predetermined portion (31w) and an outer periphery of the recessed portion (35a) in a cross section along a through direction of the through-hole (35h).

Description

Technical Field

[0001] This disclosure relates to secondary batteries and battery packs, and methods for manufacturing them. Background Technology

[0002] A battery pack, which consists of multiple individual cells electrically connected to each other, is used, for example, as a high-output power source for driving vehicles. Examples of individual cells constituting such a battery pack include secondary batteries such as lithium-ion batteries. Such secondary batteries typically include, for example, electrodes that serve as power generation elements, a battery casing housing the electrodes, terminals electrically connected to the electrodes, and external conductive members connected to the terminals outside the battery casing. During the manufacturing process of secondary batteries, it is sometimes necessary to join the components together. Patent Document 1 describes joining the components constituting a secondary battery together by irradiating them with energy rays.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-125491 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in battery packs, for example, two individual cells are interconnected by mounting a busbar and attaching it to the external conductive members of two adjacent individual cells. The inventors desire a more stable connection between the external conductive members and the busbar.

[0008] Methods for solving problems

[0009] According to the technology disclosed herein, a method for manufacturing a secondary battery is provided. The secondary battery is equipped with: an electrode body including a positive electrode and a negative electrode; a battery casing housing the electrode body; a terminal electrically connected to the positive or negative electrode and mounted on the battery casing; and an external conductive member having a through hole and being joined to the terminal outside the battery casing. The manufacturing method includes: an mounting step of mounting the terminal to the battery casing; a configuration step of placing a portion of the terminal mounted on the battery casing into the through hole of the external conductive member; a covering step, after the configuration step, covering at least a portion of the upper surface of the external conductive member with a cover member; and a joining step, after the covering step, joining the external conductive member to the terminal by irradiation with energy rays. The external conductive member has a generally annular recess around the through hole, recessed from the upper surface of the external conductive member. In the above-described joining process, in a cross-section along the through-hole direction, with the edge of the cover member positioned between the predetermined joining portion of the external conductive member and the terminal and the outer periphery of the recess, the external conductive member is joined to the terminal.

[0010] In this manufacturing method, since the upper surface of the external conductive member around the through hole is covered by the cover member when the external conductive member is joined to the terminal, it is possible to suppress spatter from adhering to the upper surface of the external conductive member. This allows for a more stable connection between the external conductive member and the busbar.

[0011] In a preferred embodiment of the manufacturing method disclosed herein, the cover member has an opening whose inner diameter is smaller than the outer diameter of the recess. By employing a cover member configured in this way, the technical effects disclosed herein can be better achieved.

[0012] In another preferred embodiment of the manufacturing method disclosed herein, the area where the cover member overlaps with the recess is annular when viewed from above. This structure allows for better achievement of the technical effects disclosed herein.

[0013] In another preferred embodiment of the manufacturing method disclosed herein, the shortest distance W1 from the periphery of the through hole to the outer periphery of the recess, when viewed from above, is 2 mm or more. This structure allows for better achievement of the technical effects disclosed herein.

[0014] In another preferred embodiment of the manufacturing method disclosed herein, the inner wall surface of the recess is a conical surface extending from the bottom of the recess to the upper surface of the external conductive member. According to this structure, in addition to the effects described above, deformation of the external conductive member during the formation of the recess can be suppressed.

[0015] In another preferred embodiment of the manufacturing method disclosed herein, in the aforementioned covering process, a cover member with an opening is used such that the inner edge of the opening overlaps with the aforementioned conical surface to cover the upper surface of the external conductive member. According to this structure, in addition to achieving a stable bonding effect between the external conductive member and the busbar, it is also possible to achieve a deformation suppression effect on the external conductive member during the formation of the recess.

[0016] In another preferred embodiment of the manufacturing method disclosed herein, the ratio (W2 / W1) of the aforementioned shortest distance W1 to the shortest distance W2 from the junction of the aforementioned conical surface and the aforementioned bottom surface to the outer periphery of the aforementioned recess when viewed from above is 0.4 or more. With this structure, both the aforementioned joint stabilization effect and the aforementioned deformation suppression effect can be achieved simultaneously.

[0017] Furthermore, according to the technology disclosed herein, a method for manufacturing a battery pack in which multiple individual cells are interconnected via busbars is provided. The method includes: manufacturing a secondary battery, which serves as one of the individual cells, using the aforementioned method for manufacturing a secondary battery; and disposing the busbars on the upper surface of an external conductive member, connecting the external conductive member to the busbars. In this method for manufacturing a battery pack, the busbars can be more stably connected to the external conductive member.

[0018] Furthermore, according to the technology disclosed herein, a secondary battery is provided, comprising: an electrode body including a positive electrode and a negative electrode; a battery casing housing the electrode body; a terminal electrically connected to the positive electrode or the negative electrode and mounted on the battery casing; and an external conductive member externally connected to the terminal outside the battery casing. In this secondary battery, the external conductive member has a through hole, and a portion of the terminal is disposed within the through hole. Around the through hole, a junction portion between the external conductive member and the terminal is provided, and a generally annular recess is provided recessed from the upper surface of the external conductive member. In plan view, the shortest distance W1 from the periphery of the through hole to the outer periphery of the recess is 2 mm or more.

[0019] In this secondary battery configuration, a terminal disposed within a through-hole is joined to the external conductive member around a recess located inside the upper surface of the external conductive member. The terminal can be joined to the external conductive member at a recessed location on its upper surface. Furthermore, when viewed from above, the distance from the periphery of the through-hole to the outer periphery of the recess is 2 mm or more. This keeps the upper surface away from the joining area between the terminal and the external conductive member, suppressing the adhesion of splashes to the upper surface during joining. Furthermore, this allows for a more stable joining of the external conductive member to the busbar.

[0020] In a preferred embodiment of the secondary battery disclosed herein, the inner wall surface of the aforementioned recess is a conical surface extending from the bottom of the recess to the upper surface of the aforementioned external conductive member. According to this structure, in addition to achieving a stable connection between the external conductive member and the busbar, it also achieves a deformation suppression effect on the external conductive member during the formation of the recess, and a suppression effect on heat generation during energization.

[0021] In another preferred embodiment of the secondary battery disclosed herein, the ratio (W2 / W1) of the aforementioned shortest distance W1 to the shortest distance W2 from the junction of the aforementioned conical surface and the aforementioned bottom surface to the outer periphery of the aforementioned recess when viewed from above is 0.4 or more. With this structure, the aforementioned effect can be better achieved.

[0022] In another preferred embodiment of the secondary battery disclosed herein, a current collector is provided that electrically connects the positive or negative electrode to the terminal. A fusible link is formed in the current collector. When a current of 1000A or more flows through the secondary battery, the fusible link melts. According to this structure, in addition to the aforementioned effects, safety is also improved.

[0023] Furthermore, according to the technology disclosed herein, a battery pack is provided in which multiple individual cells are electrically connected to each other via a busbar. This battery pack includes the aforementioned secondary battery as one of the individual cells. The busbar is disposed on the upper surface of the aforementioned external conductive member, and the individual cells are connected to each other via the busbar. In this battery pack configuration, the busbar is more stably connected to the external conductive member.

[0024] In another preferred embodiment of the secondary battery disclosed herein, the aforementioned busbar covers both the aforementioned through hole and the aforementioned recess. According to this structure, in addition to achieving the aforementioned effects, a heat suppression effect during energization can also be achieved. Attached Figure Description

[0025] Figure 1 The diagram schematically represents a perspective view of a secondary battery according to one embodiment.

[0026] Figure 2yes Figure 1 Sectional view II-II.

[0027] Figure 3 This is a three-dimensional view showing the electrode body installed on the sealing plate.

[0028] Figure 4 This is a three-dimensional view of the electrode body with the second collector installed.

[0029] Figure 5 This is a schematic diagram illustrating the structure of the electrode.

[0030] Figure 6 It is Figure 2 A magnified view of the area near the positive end of the electrode.

[0031] Figure 7 It is Figure 6 A magnified partial view.

[0032] Figure 8 This is a diagram illustrating one step in a manufacturing method according to one embodiment.

[0033] Figure 9 This is a diagram illustrating one step in a manufacturing method according to one embodiment.

[0034] Figure 10 This is a perspective view of a battery pack according to one embodiment.

[0035] Figure 11 This is a magnified view of the vicinity of the positive terminal in another implementation. Detailed Implementation

[0036] Hereinafter, with reference to the accompanying drawings, several preferred embodiments of the technology disclosed herein will be described. Of course, the embodiments described herein are not intended to specifically limit the invention. The various drawings are schematic and do not necessarily reflect actual objects. Furthermore, components and parts that perform the same function are appropriately given the same reference numerals, and repeated descriptions are omitted. In addition, matters other than those specifically mentioned in this specification, matters necessary for implementing the technology disclosed herein (e.g., the general structure and manufacturing process of secondary batteries that do not characterize the technology disclosed herein) can be understood by those skilled in the art based on prior art in this field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in this field. Furthermore, in this specification, the notation "A~B" indicating a numerical range means "above A and below B," and also includes cases exceeding A and below B.

[0037] In this specification, the term "secondary battery" refers to all energy storage devices that can be repeatedly charged and discharged, including so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries or nickel-metal hydride batteries, as well as capacitors such as double-layer capacitors.

[0038] In the accompanying drawings referenced in this specification, the symbol X indicates the "depth direction," Y indicates the "width direction," and Z indicates the "height direction." Furthermore, in the depth direction X, F indicates "front," and Rr indicates "rear." In the width direction Y, L indicates "left," and R indicates "right." And in the height direction Z, U indicates "up," and D indicates "down." However, these directions are merely for illustrative purposes and do not limit the arrangement of the secondary battery or the battery pack.

[0039] First Implementation Method

[0040] <Secondary Battery 1>

[0041] Figure 1 This is a perspective view schematically representing a secondary battery according to one embodiment. Figure 2 yes Figure 1 Sectional view II-II. (See example) Figure 1 , 2 As shown, the secondary battery 1 is equipped with a battery casing 10, an electrode body 20, a positive terminal 30, a negative terminal 40, external conductive members 35 and 45, a positive current collector 50, a negative current collector 60, an insulating member 70, a gasket 90, and an external insulating member 92. The positive current collector 50 has a first current collector 51 and a second current collector 52, which will be described in detail later. Similarly, the negative current collector 60 has a first current collector 61 and a second current collector 62. In this embodiment, the secondary battery 1 is a lithium-ion secondary battery. Although not shown in the figure, the secondary battery 1 is, for example, equipped with an electrolyte. There are no specific limitations on the electrolyte; any electrolyte used in this type of lithium-ion secondary battery can be used. Since the composition of such an electrolyte is not a characteristic element of the technology disclosed herein, a detailed description is omitted here.

[0042] In this embodiment, the battery casing 10 is a frame that houses the electrode body 20 and the electrolyte. The battery casing 10 has a flat, bottomed cuboid shape (prism). The material of the battery casing 10 can be the same as previously used materials, without particular limitation. The battery casing 10 is preferably made of metal, for example, preferably aluminum, aluminum alloy, iron, iron alloy, etc.

[0043] In this embodiment, the battery casing 10 is equipped with an outer packaging body 12 and a sealing plate (cap) 14. The outer packaging body, such as... Figure 1As shown, the package includes: a planar rectangular bottom 12a, a pair of first sidewalls 12b extending in the height direction Z from opposite sides of the bottom 12a and facing each other, and a pair of second sidewalls 12c extending in the height direction Z from opposite sides of the bottom 12a and facing each other. In this embodiment, the first sidewalls 12b are long sidewalls extending from opposite long sides of the bottom 12a. The second sidewalls 12c are short sidewalls extending from opposite short sides of the bottom 12a. In this embodiment, the area of ​​the second sidewalls 12c is smaller than the area of ​​the first sidewalls 12b. The portion opposite the bottom 12a and surrounded by the pair of first sidewalls 12b and the pair of second sidewalls 12c forms the opening 12h. A sealing plate 14 is a component that seals the opening 12h of the outer packaging 12. The sealing plate 14 is opposite the bottom 12a of the outer packaging 12. The sealing plate 14 is generally rectangular in shape when viewed from above. The battery casing 10 is integrally formed by being joined to the periphery of the opening of the outer packaging body 12 via a sealing plate 14. The joining method is, for example, welding such as laser welding. The battery casing 10 is then airtightly sealed.

[0044] The sealing plate 14 is provided with an injection hole 15 and a gas discharge valve 17. The injection hole 15 is used to inject electrolyte after the sealing plate 14 is assembled into the outer packaging body 12. The injection hole 15 is sealed by the sealing member 16. The gas discharge valve 17 is a thin-walled part configured to break when the pressure inside the battery housing 10 reaches a specified value or above, thereby venting the gas inside the battery housing 10 to the outside.

[0045] Figure 3 It is a three-dimensional view showing the electrode body installed on the sealing plate. Figure 4 This is a perspective view showing the electrode body with the second collector installed. (Example) Figure 3 As shown, the secondary battery 1 is equipped with three electrode bodies 20. Figure 3 , 4 As shown, the second current collector 52 of the positive current collector 50 is disposed on one side in the long side direction Y. Figure 3 , 4 On the left side), the second collector portion 62 of the negative electrode collector 60 is disposed on the other side in the long side direction Y. Figure 3 , 4 On the right side), the collectors are connected in parallel. For example... Figure 2 As shown, one or more electrode bodies 20 are disposed inside the outer packaging 12, covered by an electrode body holder 29 made of a sheet of resin such as polypropylene (PP). Furthermore, there is no specific limitation on the number of electrode bodies 20 housed in the secondary battery 1; for example, it can be one, two, or more than four.

[0046] The electrode 20 is a power generation element of the secondary battery 1, and includes a positive electrode and a negative electrode. Figure 5 This is a schematic diagram illustrating the structure of the electrode. For example... Figure 5 As shown, the electrode body 20 includes a positive electrode plate 22, a negative electrode plate 24, and a spacer 26 disposed between the positive electrode plate 22 and the negative electrode plate 24. Figure 5 As shown, the electrode body 20 is a wound electrode body formed by stacking and winding strip-shaped positive electrode plates 22 and strip-shaped negative electrode plates 24 along its length using strip-shaped spacers 26. Figures 2-4 As shown, the electrode body 20 is equipped with an electrode body body portion 20a, a positive electrode connector group 23, and a negative electrode connector group 25. The electrode body body portion 20a is a portion in which the positive electrode plate 22, the negative electrode plate 24, and the spacer 26 are stacked, for example, in a flat shape.

[0047] The width of the electrode body portion 20a is, for example, 20 cm or more. The width of the electrode body portion 20a may also be, for example, 25 cm or more. The width of the electrode body portion 20a may be, for example, 40 cm or less, or 30 cm or less. In this specification, "width of the electrode body portion 20a" refers, for example, to the width in the shorter direction of the negative electrode plate 24 (in...). Figure 5 The length of the electrode body 20a in the width direction (Y) is shown in the middle.

[0048] like Figure 1 , 2 As shown in Figure 5, the electrode body 20 is arranged inside the outer packaging body 12 with its winding axis WL parallel to the width direction Y. In this embodiment, the electrode body 20 is arranged inside the outer packaging body 12 with its winding axis WL parallel to the bottom 12a and orthogonal to the second sidewall 12c. Furthermore, the two end faces of the electrode body 20 along the direction of the winding axis WL are opposite to the second sidewall 12c of the outer packaging body 12. In this specification, for ease of explanation, the side closest to the positive current collector 50 will be referred to as ( Figure 2 , 4 The end face of the electrode body 20 (e.g., electrode body body 20a) opposite the second sidewall 12c (on the left side in the width direction Y) is called the "first end face 201". The side closest to the negative electrode current collector 60 ( Figure 2 , 4 The end face of the electrode body 20 (e.g., electrode body body 20a) opposite the second sidewall 12c (to the right of the width direction Y) is called the "second end face 202".

[0049] The positive electrode plate 22 has a strip-shaped positive electrode current collector foil 22c (e.g., aluminum foil) and a positive electrode active material layer 22a fixed to at least one surface of the positive electrode current collector foil 22c. Although there are no specific limitations, a positive electrode protective layer 22p may also be provided as needed on one side edge in the width direction Y of the positive electrode plate 22. In addition, since the materials constituting the positive electrode active material layer 22a or the positive electrode protective layer 22p can be any materials used in such secondary batteries (in this embodiment, lithium-ion secondary batteries) without specific limitations, and are not a characteristic element of the technology disclosed herein, a detailed description thereof is omitted here.

[0050] At one end of the positive electrode current collector foil 22c in the width direction Y ( Figure 5 At the left end, multiple positive terminals 22t are provided. These multiple positive terminals 22t are respectively positioned on one side of the width direction Y (…). Figure 5 The positive electrode connectors 22t protrude from the left side of the positive electrode plate 22. Multiple positive electrode connectors 22t are spaced apart (intermittently) along the length of the positive electrode plate 22. The positive electrode connectors 22t are part of the positive electrode current collector foil 22c, specifically the portion of the positive electrode current collector foil 22c where the positive electrode active material layer 22a and the positive electrode protective layer 22p are not formed (exposed portion of the current collector foil). In this embodiment, the multiple positive electrode connectors 22t protrude beyond the spacer 26 in the width direction Y. For example, at one end of the multiple positive electrode connectors 22t in the width direction Y (… Figure 5 The left end) are stacked to form the positive electrode connector group 23 (refer to Figures 2-4 ).like Figure 2 As shown, the positive current collector 50 is connected to the positive terminal assembly 23.

[0051] The negative electrode plate 24 has a strip-shaped negative electrode current collector foil 24c (e.g., aluminum foil) and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode current collector foil 24c. Furthermore, since the material constituting the negative electrode active material layer 24a can be any material used in such a secondary battery (in this embodiment, a lithium-ion secondary battery) without specific limitations, and is not a characteristic element of the technology disclosed herein, its detailed description is omitted here.

[0052] At one end in the width direction Y of the negative electrode current collector foil 24c ( Figure 5 On the right end), multiple negative terminals 24t are provided. These multiple negative terminals 24t are positioned towards one side in the width direction Y ( Figure 5The right side of the negative electrode plate 24 protrudes. Multiple negative electrode connectors 24t are spaced apart (intermittently) along the length of the negative electrode plate 24. Here, the negative electrode connector 24t is part of the negative electrode current collector foil 24c, specifically the portion of the negative electrode current collector foil 24c where the negative electrode active material layer 24a is not formed (exposed current collector foil portion). In this embodiment, the negative electrode connector 24t protrudes beyond the spacer 26 in the width direction Y. For example, one end of the multiple negative electrode connectors 24t in the width direction Y ( Figure 5 The right end of the stacked layers form the negative terminal assembly 25 (refer to the right end). Figures 2-4 ).like Figure 2 As shown, the negative current collector 60 is joined to the negative terminal assembly 25.

[0053] The spacer 26 is a component that insulates the positive electrode active material layer 22a of the positive electrode plate 22 from the negative electrode active material layer 24a of the negative electrode plate 24. The spacer 26 forms the outer surface of the electrode body 20. As the spacer 26, for example, a porous sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is used.

[0054] like Figures 1-3 As shown, the positive terminal 30 and the negative terminal 40 are mounted on the sealing plate 14. In this embodiment, the positive terminal 30 is disposed at one end of the sealing plate 14 in the long side direction Y. Figures 1-3 The left end). In this embodiment, the negative end 40 is disposed at the other end of the sealing plate 14 in the long side direction Y (the left end). Figures 1-3 (The right end). Positive terminal 30 and negative terminal 40 are examples of terminals.

[0055] like Figure 2 As shown, the positive terminal 30 is electrically connected to the positive electrode plate 22 of the electrode body 20 via the positive current collector 50 inside the outer packaging 12 (see reference). Figure 5 The positive terminal 30 is inserted through the terminal lead-out hole 18 and led out from the inside of the sealing plate 14 to the outside. The positive terminal 30 is insulated from the sealing plate 14 by means of an insulator 70 and a washer 90. The positive terminal 30 is preferably made of metal, for example, preferably aluminum or an aluminum alloy. An external conductive member 35 is fixed to the positive terminal 30. The positive terminal 30 is engaged with the external conductive member 35.

[0056] Figure 6 It is Figure 2 A magnified view of the vicinity of the positive extremum 30. Figure 7 It is Figure 6 A magnified partial view. For example... Figure 6 As shown, the positive terminal 30 has an insertion through portion 30a, a flange portion 30b, and a protrusion portion 30c.

[0057] The insertion through-hole 30a is, for example, a portion smaller in shape than the terminal lead-out hole 18 of the sealing plate 14. In this embodiment, the insertion through-hole 30a penetrates the sealing plate 14 of the battery casing 10. Figure 6 As shown, the insertion through-hole 30a is sequentially inserted from the sealing plate 14 side into the interior of the cylindrical portion 91 of the through-hole washer 90, the terminal lead-out hole 18 of the sealing plate 14, the hole 70h of the insulating member 70, and the hole 51h of the first current collector 51. The lower end of the insertion through-hole 30a is joined to the first current collector 51, for example, by welding or mechanical joining (riveting, etc.).

[0058] The flange portion 30b is, for example, a portion whose outer diameter is larger than the terminal lead-out hole 18 of the sealing plate 14 (expanded diameter portion). In this embodiment, the flange portion 30b is disposed at the upper end of the insertion through portion 30a. Figure 6 As shown, the flange 30b protrudes from the terminal lead-out hole 18 and is disposed on the outside of the battery housing 10. The flange 30b is disposed on the upper surface of the sealing plate 14 (the side away from the outer packaging 12). The flange 30b is formed, for example, into a polygonal shape such as a generally circular or quadrilateral shape when viewed from above. Above the flange 30b, for example, an external conductive member 35 is disposed. Here, the flange 30b is in direct contact with the external conductive member 35.

[0059] The protrusion 30c is, for example, the portion that protrudes upward from the upper end of the flange 30b (on the side opposite to the insertion through portion 30a). Figure 6 As shown, the protrusion 30c is disposed (inserted) into the through hole 35h of the external conductive member 35. In this embodiment, the protrusion 30c is joined to the external conductive member 35. A joining portion 31w is formed in the protrusion 30c to engage with the external conductive member 35. Here, the protrusion 30c is formed in a generally annular shape (preferably circular) when viewed from above. However, the protrusion 30c may also be formed in a columnar shape (solid shape).

[0060] External conductive member 35 is, for example, a member that is attached to the positive terminal 30 outside the battery casing 10. Figure 1As shown, the external conductive member 35 is a generally rectangular shape that extends along its long side in the Y direction. The external conductive member 35 is preferably plate-shaped. The external conductive member 35 is, for example, made of metal. The external conductive member 35 is preferably made of aluminum or an aluminum alloy. The external conductive member 35 is mounted on the sealing plate 14, for example, on the positive electrode side of the secondary battery 1, insulated from the sealing plate 14 by means of the external insulating member 92. In this embodiment, the lower surface 35d of the external conductive member 35 is disposed on the sealing plate 14 side. Furthermore, for example, when constructing the battery pack, a busbar is joined to the external conductive member 35. In this embodiment, the busbar is joined to the upper surface 35u on the side opposite to the lower surface 35d. The upper surface 35u and the lower surface 35d will be further described later.

[0061] In this embodiment, the external conductive member 35 is engaged with the positive terminal 30 at the junction 31w.

[0062] However, terminals and external conductive components are joined together, for example, by irradiation with energy rays such as laser welding. For example, when energy rays are irradiated onto the predetermined joining area, spatter may scatter and adhere to the external conductive component. The inventors wish to suppress the adhesion of spatter to the external conductive component during the joining of the terminal and the external conductive component, and to more stably join the external conductive component to the busbar. Therefore, the inventors have conducted in-depth research on the shape of the external conductive component and the joining method between the terminal and the external conductive component.

[0063] like Figure 6 As shown, the external conductive member 35 has a through hole 35h. The through hole 35h is, for example, generally circular in shape when viewed from above. In this embodiment, the through hole 35h is positioned at one end in the same direction as the center of the external conductive member 35 in the longitudinal direction (e.g., Figure 1 (The left end of the width direction Y in the figure). In this embodiment, a portion of the positive terminal 30 (e.g., the protrusion 30c) is disposed within the through hole 35h. Additionally, a joint 31w, where the external conductive member 35 engages with the positive terminal 30 (the protrusion 30c in this figure), is provided around the through hole 35h. In this embodiment, the joint 31w is a welded joint formed by welding performed by irradiation with energy rays.

[0064] The joint 31w is configured, for example, to be generally annular (e.g., circular) when viewed from above. In this case, to make the engagement between the external conductive member 35 and the positive terminal 30 more stable, the width of the joint 31w in the radial direction of the through hole 35h (e.g., the ring width) is preferably 0.5 mm to 0.9 mm. The joint 31w is preferably provided continuously. Alternatively, the joint 31w may be provided intermittently or in a dotted line pattern. The joint 31w may also be provided symmetrically with respect to the axis of the positive terminal 30, for example.

[0065] Furthermore, in this embodiment, a generally annular first recess 35a, recessed from the upper surface 35u of the external conductive member 35, is provided around the through hole 35h. In this specification, the term "upper surface 35u of the external conductive member 35" refers to the external conductive member 35 in the through-hole 35h direction (e.g., ...). Figure 6 One end face in the direction Z) is the face opposite to the sealing plate 14. For example... Figure 6 , 7 As shown, the diameter of the first recess 35a is larger than the diameter of the through hole 35h. Furthermore, the first recess 35a is configured to surround the periphery of the joint 31w. Figure 7 As shown, the inner wall surface 35a2 of the first recess 35a extends substantially perpendicularly from the bottom surface 35a1 to the upper surface 35u. The angle between the inner wall surface 35a2 and the bottom surface 35a1 is, for example, 80 degrees to 100 degrees. Furthermore, the first recess 35a is an example of a "recess".

[0066] In this embodiment, from by Figure 7 The shortest distance W1 (hereinafter simply referred to as "distance W1") from the periphery of the through hole 35h to the outer periphery of the first recess 35a, viewed from above in the direction of arrow A, is 2 mm or more (e.g., 2.5 mm or more). Since distance W1 is within the aforementioned range, during the manufacturing process of the secondary battery 1, it is possible to suppress the adhesion of spatter to the upper surface 35u, thus enabling a more stable connection between the external conductive member 35 and the busbar. From this perspective, distance W1 is preferably 2.5 mm or more. Distance W1 is, for example, 4.0 mm or less, and considering the connection with the busbar, preferably 3.5 mm or less, more preferably 3.0 mm or less.

[0067] like Figure 7 As shown, inside the first recess 35a, a protrusion 35b is provided around the through hole 35h. The protrusion 35b is, for example, generally annular (e.g., circular) when viewed from above. In this embodiment, the protrusion 35b protrudes from the bottom surface 35a1 of the first recess 35a to the upper surface 35u. The front end portion 35b1 of the protruding direction of the protrusion 35b is as follows... Figure 7The portion shown is located on the side closer to the bottom surface 35a1 than the upper surface 35u. In this embodiment, a joint portion 31w is provided at the junction of the front end portion 35b1 and the protrusion 30c. By providing the protrusion 35b, for example, the joining process performed by irradiating energy rays at the junction of the external conductive member 35 and the positive terminal 30 can be made more efficient. Therefore, the output of energy rays can be reduced and the generation of spatter can be suppressed, thus achieving a better effect of suppressing spatter adhesion. However, the formation of the protrusion 35b is not necessary and can be omitted in other embodiments.

[0068] The first depth D1 of the first recess 35a is, for example, 0.1 mm to 1.2 mm. In this specification, the term "first depth D1 of the first recess 35a" refers, for example, to the maximum depth from the upper surface 35u of the external conductive member 35 to the bottom surface 35a1 of the first recess 35a. Furthermore, the second depth D2 of the first recess 35a is, for example, 0.05 mm or more, preferably 0.1 mm or more, and more preferably 0.5 mm or more. The second depth D2 is, for example, 1.0 mm or less, or 0.9 mm or less. In this specification, the term "second depth D2 of the first recess 35a" refers, for example, to the maximum depth from the upper surface 35u of the external conductive member 35 to the front end portion 35b1 of the protrusion 35b. In this embodiment, the second depth D2 may also be defined as the maximum depth from the upper surface 35u to the joint portion 31w.

[0069] exist Figure 7 In the illustrated embodiment, a generally annular second recess 35c, recessed from the lower surface 35d of the external conductive member 35, is provided around the through hole 35h. In this specification, the term "lower surface 35d of the external conductive member 35" refers to the external conductive member 35 in the through-hole 35h direction (e.g., ...). Figure 6 One end face in the Z direction is the face of the sealing plate 14. In this embodiment, the second recess 35c is opposite to the flange 30b of the positive terminal 30. The diameter of the second recess 35c is, for example, larger than the diameter of the through hole 35h. By providing the second recess 35c, a space 31s is ensured around the through hole 35h. With the help of the space 31s, interference from the external conductive member 35 to the junction of the flange 30b and the protrusion 30c can be suppressed. Therefore, the external conductive member 35 can be stably disposed on the flange 30b, thereby suppressing the occurrence of spatter during welding.

[0070] Furthermore, a thin-walled portion 35t is formed by providing the second recess 35c. The thickness of the thin-walled portion 35t is smaller than the thickness of other portions of the external conductive member 35 where the first recess 35a and the second recess 35c are not provided. The thin-walled portion 35t can also be configured to melt, for example, when a current of 1000A or more (e.g., a short-circuit current) flows through the secondary battery 1. However, the formation of the second recess 35c is not necessary and can be omitted in other embodiments.

[0071] Negative extreme 40 such Figure 2 As shown, the negative electrode plate 24 of the electrode body 20 is electrically connected to the inner packaging 12 via the negative electrode current collector 60 (see reference). Figure 5 The negative terminal 40 is inserted into the through terminal lead-out hole 19 and led out from the inside of the sealing plate 14. The negative terminal 40 is insulated from the sealing plate 14 by means of the insulating member 70 and the washer 90. The negative terminal 40 is preferably made of metal, more preferably, for example, copper or copper alloy. The negative terminal 40 may also be constructed by joining and integrating two conductive members. For example, the part of the negative terminal 40 connected to the negative current collector 60 may be made of copper or copper alloy, while the part exposed on the outside of the sealing plate 14 may be made of aluminum or aluminum alloy. The negative terminal 40 may also be made of a cladding material of aluminum-based metals and copper-based metals. The specific structure of the negative terminal 40 may be the same as that of the positive terminal 30. The external conductive member 45 is fixed to the negative terminal 40. The negative terminal 40 is engaged with the external conductive member 45.

[0072] The external conductive member 45 is, for example, a member that is joined to the negative terminal 40 outside the battery casing 10. The external conductive member 45 is mounted on the sealing plate 14 on the negative side of the secondary battery 1 in a state of insulation from the sealing plate 14 by means of the external insulating member 92. The shape, structure and constituent materials of the external conductive member 45 can be the same as those of the external conductive member 35 on the positive side.

[0073] The positive current collector 50 is, for example, a component inside the outer casing 12 that electrically connects the positive plate 22 of the electrode body 20 to the positive terminal 30. Figure 2 As shown, the positive electrode current collector 50 is equipped with a first current collector 51 and a second current collector 52. The first current collector 51 is, for example, formed with an L-shaped cross-section. The first current collector 51, for example, has a base 51a and a lead portion 51b. Figure 2 As shown, the base 51a is disposed along the inner surface of the sealing plate 14. Figure 6As shown, a hole 51h is formed at the base 51a at a position corresponding to the terminal lead-out hole 18 of the sealing plate 14. For example, the insertion through-hole 30a of the positive terminal 30 is inserted through this hole 51h. The lead portion 51b extends from one end of the base 51a in the width direction Y toward the base 12a. For example, the second current collector 52 is connected to the lead portion 51b.

[0074] like Figures 2-4 As shown, the second current collector 52 extends towards the bottom 12a of the outer packaging body 12. In this embodiment, the second current collector 52 has a first connecting portion 52a and a second connecting portion 52b. The first connecting portion 52a is, for example, a portion electrically connected to the first current collector 51. In this embodiment, the first connecting portion 52a is connected to the first current collector 51 via a connecting portion 521. The connecting portion 521 is, for example, a thin-walled portion. The first connecting portion 52a extends, for example, along the vertical direction Z. In this embodiment, the first connecting portion 52a is arranged substantially perpendicular to the winding axis WL of each electrode body 20.

[0075] like Figure 3 , 4 As shown, a fuse portion 52f is formed in the first connection portion 52a. The first connection portion 52a is configured such that when a current of 1000A or more (e.g., a short-circuit current) flows through the secondary battery 1, the fuse portion 52f melts. The fuse portion 52f is, for example, a portion in the first connection portion 52a with a cross-sectional area smaller than the cross-sectional area of ​​other portions besides the fuse portion 52f and the connection portion 521. The fuse portion 52f is, for example, an opening, a thin-walled portion, etc. Because the first connection portion 52a is configured with the fuse portion 52f, it will melt when the current flows as described above. Therefore, safety is improved.

[0076] The second connection portion 52b is, for example, the portion that engages with the positive electrode connector group 23. In this embodiment, the second connection portion extends along the vertical direction Z. The second connection portion 52b is arranged substantially perpendicular to the winding axis WL of each electrode body 20. The surface of the second connection portion 52b that connects with the plurality of positive electrode connectors 22t is arranged substantially parallel to the second sidewall 12c of the outer packaging body 12.

[0077] The negative current collector 60 is a component inside the outer casing 12 that electrically connects the negative electrode plate 24 of the electrode body 20 to the negative terminal 40. The negative current collector 60 is as follows: Figures 2-4 The device shown has a first current collector 61 and a second current collector 62. The first current collector 61 has a base 61a and a lead portion 61b. The second current collector 62 has a first connection portion 62a and a second connection portion 62b. Since the structure of the negative current collector 60 is the same as that of the positive current collector 50 described above, its detailed description is omitted here. Furthermore, regarding the negative current collector 60, Figure 4The marking "621" indicates the connection part, "62a" indicates the first connection part, "62b" indicates the second connection part, and "62f" indicates the fuse part.

[0078] The insulating member 70 is an insulating member disposed between the inner surface of the positive current collector 50 and the sealing plate 14. An opening 70h is formed in the insulating member 70. The washer 90 is an insulating member disposed between the outer surface of the positive terminal 30 and the sealing plate 14. The washer 90 has a hollow cylindrical portion 91 that is inserted into the terminal lead-out hole 18 of the sealing plate 14. The cylindrical portion 91 of the washer 90 is disposed along the inner circumference of the opening 70h in the insulating member 70. Furthermore, for the insulating structure employing the insulating member 70 and the washer 90, the same structure is also provided on the negative terminal 40 side; its detailed description is omitted.

[0079] There are no specific limitations on the structural material of the insulating component 70 or the washer 90; it can be a polyolefin resin (e.g., polypropylene (PP), polyethylene (PE)), a fluorinated resin (e.g., perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE)), or other resin materials. Additionally, such resin materials can also be used as structural materials for the external insulating component 92.

[0080] The aforementioned secondary battery 1 is equipped with: an electrode body 20 including a positive electrode plate 22 and a negative electrode plate 24, a battery casing 10 housing the electrode body 20, a positive terminal 30 electrically connected to the positive electrode plate 22 and mounted on the battery casing 10, and an external conductive member 35 externally connected to the positive terminal 30 and joined to the positive terminal 30. The external conductive member 35 has a through hole 35h. A portion of the positive terminal 30 is disposed within the through hole 35h. Around the through hole 35h, a joint portion 31w between the external conductive member 35 and the positive terminal 30 is provided, and a generally annular first recess 35a recessed from the upper surface 35u of the external conductive member 35 is provided. Here, when viewed from above, the distance W1 from the periphery of the through hole 35h to the outer periphery of the first recess 35a is 2 mm or more.

[0081] In other words, in the secondary battery 1, the positive terminal 30 disposed within the through hole 35h, which is located inside the first recess 35a recessed from the upper surface 35u of the external conductive member 35, is joined to the external conductive member 35. The positive terminal 30 can be joined to the external conductive member 35 at the recessed portion from the upper surface 35u. Furthermore, when viewed from above, there is a distance of 2 mm or more from the periphery of the through hole 35h to the outer periphery of the first recess 35a. This allows the upper surface 35u to be kept away from the joining portion of the positive terminal 30 and the external conductive member 35, suppressing the adhesion of spatter to the upper surface 35u during joining. Therefore, the external conductive member 35 can be joined to the busbar more stably.

[0082] The secondary battery 1 can be used for various purposes, such as serving as a power source (drive power supply) for motors in vehicles such as passenger cars and trucks. There are no specific restrictions on the type of vehicle; for example, plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs) can be listed.

[0083] <Manufacturing Method of Secondary Battery 1>

[0084] The battery casing 10, electrode body 20, positive terminal 30, negative terminal 40, external conductive components 35 and 45, positive current collector 50, negative current collector 60, insulating component 70, gasket 90, and external insulating component 92 described above are prepared. For example, the secondary battery 1 can be manufactured using a manufacturing method that includes an installation process, a configuration process, a covering process, and a bonding process. Furthermore, this manufacturing method may also include other processes at any stage. Reference will be made as appropriate in the following description. Figures 1-9 .

[0085] In the installation process, for example, the positive terminal 30 is installed onto the battery casing 10. In this embodiment, firstly, the positive terminal 30, the gasket 90, the first current collector 51, and the insulating member 70 are installed onto the sealing plate 14.

[0086] The positive terminal 30, the first current collector 51, and the insulating component 70 are fixed to the sealing plate 14, for example, by riveting. The riveting process is as follows: Figure 6 The diagram shows the process of clamping the washer 90 between the outer surface of the sealing plate 14 and the positive terminal 30, and then clamping the insulating member 70 between the inner surface of the sealing plate 14 and the first current collector 51. For example, before riveting, the insertion through-hole 30a of the positive terminal 30 is inserted sequentially from above the sealing plate 14 into the cylindrical portion 91 of the washer 90, the terminal lead-out hole 18 of the sealing plate 14, the hole 70h of the insulating member 70, and the hole 51h of the first current collector 51, protruding downwards from the sealing plate 14. Then, the portion of the sealing plate 14 protruding downwards beyond the insertion through-hole 30a is riveted to apply a compressive force in the vertical direction Z. Using the same sequence, the negative terminal 40, washer 90, first current collector 61, and insulating member 70 are fixed to the sealing plate 14.

[0087] In the configuration process, for example, a portion of the positive terminal 30 mounted on the battery housing 10 is configured into the through hole 35h of the external conductive member 35. In this embodiment, after the configuration process, the external insulating member 92 is configured from above the sealing plate 14 such that the flange 30b of the positive terminal 30 and the gasket 90 are accommodated into the hole 92h of the external insulating member 92. Next, the external conductive member 35 is overlapped with the positive terminal 30 from above the sealing plate 14 such that the lower surface 35d is opposite to the flange 30b and the protrusion 30c is inserted into the through hole 35h. For the negative side, for example, a portion of the negative terminal 40 mounted on the battery housing 10 (e.g., the protrusion of the negative terminal 40) is configured into the through hole of the external conductive member 45 (not shown in the figure) in the same order.

[0088] In the covering process, for example after the configuration process, at least a portion of the upper surface of the outer conductive member 35 is covered by the cover member. Figure 8 , 9 This is a diagram illustrating one step in a manufacturing method according to one embodiment. Figure 8 This is a diagram showing the state in which the upper surface 35u of the external conductive component 35 after the configuration process is covered by the cover component 2, viewed from the upper surface 35u side. Figure 9 From Figure 8 A partial cross-sectional view viewed in the direction of arrow IX. There are no specific limitations on the cover member 2; for example, it may be a component provided with an apparatus for manufacturing the secondary battery 1. While there are no specific limitations on the cover member 2, it is preferably made of resin or metal. The material constituting the cover member 2 is preferably a material that is difficult to melt or deform due to the joining process described later.

[0089] In this embodiment, an opening 2h is formed in the cover member 2. For example... Figure 8 As shown, the opening 2h is annular when viewed from above. Preferably, the inner diameter Dc of the opening 2h is smaller than the outer diameter Da of the first recess 35a. By using a cover member 2 with an opening having an inner diameter smaller than the outer diameter Da of the first recess 35a, it is possible to better suppress the adhesion of spatter to the upper surface 35u during the joining process. In this specification, the term "outer diameter Da of the first recess 35a" refers to... Figure 9 The figure shows the diameter of the first recess 35a in the upper surface 35u of the external conductive member 35 (in...). Figure 8 , 9 In this embodiment, the inner diameter Dc of the opening 2h is larger than the inner diameter Db of the through hole 35h.

[0090] In the covering process, such as Figure 8 , 9As shown, along the penetration direction of the through hole 35h ( Figure 9 In the cross-sectional view (Z) of the direction, the upper surface 35u is covered by the cover member 2, such that the inner edge of the opening 2h of the cover member 2 is positioned at the outer periphery of the predetermined joint portion 31w of the external conductive member 35 and the positive terminal 30 and the first recess 35a (in Figure 8 , 9 In the middle, between the marker K). The pre-joined part 31w becomes the joint part 31w after the jointing process described later is performed (see reference). Figure 6 , 7 For example, the pre-engaged portion 31w is located at the junction of the periphery of the through hole 35h and the outer edge of the protrusion 30c.

[0091] exist Figure 8 In the embodiment shown, the upper surface 35u of the external conductive member 35, except for the first recess 35a, is completely covered by the cover member 2.

[0092] In the bonding process, for example after the covering process, the external conductive member 35 is bonded to the positive terminal 30 by irradiation with energy rays. By performing the bonding process, for example, a bonding portion 31w is formed (see reference). Figure 6 , 7 In this embodiment, along the through-hole 35h in the through-direction (in Figure 9 In the cross-sectional view (Z direction), with the edge of the opening 2h of the cover member 2 positioned between the predetermined engagement portion 31w of the external conductive member 35 and the positive terminal 30 and the outer periphery of the first recess 35a, the external conductive member 35 and the positive terminal 30 are joined together. Since the external conductive member 35 and the positive terminal 30 are joined while the upper surface 35u around the through hole 35h is covered by the cover member 2, it is possible to suppress the adhesion of splashes to the upper surface 35u.

[0093] The energy used for irradiation by energy rays includes, for example, light energy, electron energy, and heat energy. In the joining process, for example, a joint is formed by using welding methods such as laser welding, electron beam welding, ultrasonic welding, resistance welding, and TIG (Tungsten Inert Gas) welding. Among these, laser welding can be used effectively.

[0094] After the bonding process, for example, the electrode body 20 is installed in the structure obtained in the bonding process. As a method for manufacturing the electrode body 20, conventionally known methods can be used without particular limitations. In this embodiment, the second current collector 52 of the positive current collector 50 is installed in the positive terminal assembly 23 of the electrode body 20, and then the second current collector 62 of the negative current collector 60 is installed in the negative terminal assembly 25. Next, the second current collectors 52 and 62 installed on the electrode body 20 are installed in the first current collectors 51 and 61 of the same polarity in the structure obtained in the above bonding process. Next, the electrode body 20 is housed in the electrode body holder 29. Next, the electrode body 20, covered by the electrode body holder 29, is inserted into the outer packaging body 12. In this state, the sealing plate 14 is overlapped with the opening 12h of the outer packaging body 12, they are welded together, and the outer packaging body 12 is sealed.

[0095] After the outer packaging 12 is sealed, electrolyte is injected into the battery casing 10 through the injection hole 15 using a method known in the past. Following the injection of electrolyte, the injection hole 15 is sealed using a sealing member 16. For example, a metal sealing plug is used as the sealing member 16, and this sealing plug is embedded in the injection hole 15. Next, with the injection hole 15 blocked by the sealing member 16, laser welding or the like is performed to seal the injection hole 15. After the above sealing, for example, initial charging and aging treatment are performed under specified conditions, thereby obtaining a usable secondary battery 1.

[0096] <Battery Pack 100>

[0097] Secondary batteries 1 are well used, for example, as single cells in the construction of battery packs. Figure 10 This is a perspective view of a battery pack according to one embodiment. For example... Figure 10 As shown, in the battery pack 100, multiple secondary batteries 1 are electrically connected to each other via a busbar 110. In this embodiment, a busbar 110 is disposed between the upper surface 35u of the external conductive member 35 on the positive electrode side of one of the two adjacent secondary batteries 1 and the upper surface 45u of the external conductive member 45 on the negative electrode side of the other secondary battery 1. The secondary batteries 1 are connected to each other via the busbar 110. As described above, the adhesion of splashes to the upper surface 35u of the external conductive member 35 (here, the surface where the busbar 110 is attached) in the secondary battery 1 is suppressed. Therefore, the busbar 110 can be more stably attached to the external conductive member 35.

[0098] Busbar 110 is, for example, a plate-shaped (rod-shaped) component. Busbar 110 is generally rectangular in length along the X direction. External conductive components 35 and 45 are electrically connected to busbar 110, for example, by welding joints such as laser welding. Busbar 110 is, for example, made of conductive metals such as aluminum, aluminum alloy, nickel, or stainless steel.

[0099] exist Figure 10 In the illustrated embodiment, the busbar 110 covers the through hole 35h and the first recess 35a on the positive electrode side, and covers the through hole 45h and the first recess 45a on the negative electrode side. This further shortens the power path in the battery pack 100, suppressing heat generation caused by power supply. In a top view, for example, the area of ​​the first recess is preferably 50% or more (preferably 70% or more, more preferably 80% or more), and is preferably covered by the busbar 110.

[0100] <Manufacturing Method of Battery Pack 100>

[0101] The manufacturing method of the battery pack 100 includes, for example, manufacturing a secondary battery 1 as a single cell; and arranging a busbar 110 on the upper surfaces 35u, 45u of the external conductive members 35, 45, and connecting the external conductive members to the busbar. For example, a plurality of secondary batteries 1 are arranged such that the first sidewalls 12b are opposite to each other. The arrangement direction of the secondary batteries 1 at this time (in...) Figure 10 In the X direction (where X is the center), for two adjacent secondary batteries 1, they are arranged such that the external conductive members 35 and 45 in the same direction are adjacent to each other. Next, a busbar 110 is mounted on and connected to the adjacent external conductive members 35 and 45. Furthermore, for example, the busbar is mounted between a pair of end plates clamping it from both ends in the arrangement direction to apply a predetermined constraint pressure, thereby manufacturing the battery pack 100. As described above, in the secondary battery 1, the adhesion of splashes to the upper surface 35u of the external conductive member 35 (here, the surface where the busbar 110 is joined) is suppressed. Therefore, the busbar 110 can be joined to the external conductive member 35 more stably.

[0102] The above provides detailed examples of the specific technologies disclosed herein; however, these are merely exemplary and do not limit the scope of the claimed protection. The technologies described in the claims include various modifications and variations of the specific examples listed above.

[0103] Second Implementation Method

[0104] In the first embodiment described above, the inner wall surface 35a2 of the first recess 35a is substantially perpendicular to the bottom surface 35a1. However, it is not limited to this. Figure 11 This is a magnified view of the vicinity of the positive terminal in another embodiment. Figure 11 The figure shows a cross-sectional view along the penetration direction (direction Z in this figure) of the through hole 35h. Figure 11 In the illustrated embodiment, the inner wall surface 35a3 of the first recess 35a is a conical surface extending from the bottom surface 35a1 of the first recess 35a to the upper surface 35u of the external conductive member 35. By forming the inner wall surface 35a3 as a conical surface, the amount of metal at the outer periphery of the first recess 35a can be reduced. During the formation of the first recess 35a, due to the metal at the outer periphery of the first recess 35a receding radially in the first recess 35a, a bulge may sometimes occur at the outer periphery. By forming the inner wall surface 35a3 as a conical surface, such bulging can be suppressed, thereby suppressing deformation of the external conductive member. In addition, stress concentration in the thin-walled portion 35t due to external forces can be suppressed. Furthermore, the heat capacity of the external conductive member 35 can be increased, and heat generation during energization can be reduced. In the following description, the inner wall surface 35a3 is also referred to as "conical surface 35a3".

[0105] In this embodiment, the inclination angle θ of the inner wall surface 35a3 is less than 80 degrees, preferably less than 45 degrees. To better achieve the above effect, the inclination angle θ is more preferably 20 to 40 degrees, and even more preferably 25 to 35 degrees. Furthermore, in this specification, the term "inclination angle θ of the inner wall surface 35a3" refers, for example, to... Figure 11 The angle between the inner wall surface 35a3 and the straight line L1 along the bottom surface 35a1 in the sectional view shown.

[0106] Furthermore, in this embodiment, when from Figure 11 When viewed from above in the direction of arrow A, the ratio (W2 / W1) of the aforementioned distance W1 to the shortest distance W2 (hereinafter simply referred to as "distance W2") from the junction B of the conical surface 35a3 and the bottom surface 35a1 to the outer periphery of the first recess 35a is 0.4 or more. Furthermore, to better achieve the above effect, the ratio (W2 / W1) is preferably 0.5 or more.

[0107] In the manufacturing method of the secondary battery according to the second embodiment, an external conductive member 35 with an inner wall surface 35a3 being the aforementioned conical surface is used. For example, in the covering process, it is preferable to cover the upper surface 35u of the external conductive member 35 (see reference 2) by means of the inner edge of the opening 2h of the cover member 2 overlapping with the conical surface 35a3. Figure 9 , 11 In this embodiment, it is possible to suppress the adhesion of spatter to peripheral components during the bonding process, and, as described above, to suppress deformation of the outer periphery of the first recess 35a. Furthermore, the reliability of the joints between the secondary battery 1 or the components constituting the battery pack 100 can be improved.

[0108] Furthermore, there are no specific limitations on the shape of the first recess 35a, as long as it achieves the technical effects disclosed herein. Additionally, in the second embodiment, except as described above, the content described in the first embodiment is omitted here.

[0109] Other Implementation Methods

[0110] In the first embodiment described above, such as Figure 8 As shown, the cover member 2 covers the entire upper surface 35u of the external conductive member 35. However, there is no specific limitation on the area covered by the cover member 2, as long as it is an area that can achieve the technical effects disclosed herein. From this point of view, the area covered by the cover member 2 is preferably 50% or more of the area of ​​the upper surface 35u, more preferably 70% or more, and even more preferably 90% or more.

[0111] In addition, in the first embodiment described above, the electrode body 20 is a wound electrode body. However, it is not limited to this and a stacked electrode body can also be used.

[0112] Explanation of reference numerals in the attached figures

[0113] 1 Secondary battery

[0114] 2 Cover components

[0115] 10 Battery casing

[0116] 12 outer packaging

[0117] 14 Sealing Board

[0118] 20 electrode body

[0119] 22 positive plate

[0120] 22a Positive Electrode Active Material Layer

[0121] 22C positive electrode current collector foil

[0122] 22p positive electrode protective layer

[0123] 22t positive terminal connector

[0124] 23 Positive Terminal Connector Assembly

[0125] 24 negative electrode plate

[0126] 24a negative electrode active material layer

[0127] 24C negative electrode current collector foil

[0128] 24t negative terminal connector

[0129] 25 negative terminal assembly

[0130] 26 spacers

[0131] 30 positive extremes

[0132] 31w Joint (Pre-joint part)

[0133] 35 External conductive components

[0134] 35a first recess

[0135] 35h through hole

[0136] 40 negative extremes

[0137] 45 External conductive components

[0138] 50 Positive Current Collector

[0139] 60 negative electrode current collector

[0140] 70 Insulating parts

[0141] 90 washers

[0142] 92 External insulation components

[0143] 100 battery pack

Claims

1. A method for manufacturing a secondary battery, wherein the secondary battery is equipped with: An electrode body, the electrode body comprising a positive electrode and a negative electrode; A battery casing that houses the electrode body; Terminals, which are electrically connected to the positive or negative terminal and are mounted on the battery casing; as well as An external conductive member, having a through hole, is joined to the terminal outside the battery housing, wherein... The manufacturing method has the following characteristics: The installation process of mounting the terminals onto the battery casing; The configuration process of configuring a portion of the terminal installed in the battery housing into the through hole of the external conductive member; Following the configuration step, a covering step is performed whereby at least a portion of the upper surface of the external conductive member is covered with a cover member; and Following the covering process, a bonding process is performed to connect the external conductive component to the terminal by irradiation with energy rays. The external conductive member has a generally annular recess around the through hole, which is recessed from the upper surface of the external conductive member. In the joining process, in a cross-section along the through-hole direction, with the edge of the cover member positioned between the predetermined joining portion of the external conductive member and the terminal and the outer periphery of the recess, the external conductive member is joined to the terminal.

2. The manufacturing method as described in claim 1, wherein, The cover member has an opening. The inner diameter of the opening is smaller than the outer diameter of the recess.

3. The manufacturing method as described in claim 1 or 2, wherein, in a top view, the area where the cover member overlaps with the recess is annular.

4. The manufacturing method according to any one of claims 1 to 3, wherein, When viewed from above, the shortest distance W1 from the periphery of the through hole to the outer periphery of the recess is greater than 2 mm.

5. The manufacturing method according to any one of claims 1 to 3, wherein, The inner wall surface of the recess is a conical surface that extends from the bottom of the recess to the upper surface of the external conductive member.

6. The manufacturing method as described in claim 4, wherein, The inner wall surface of the recess is a conical surface that extends from the bottom of the recess to the upper surface of the external conductive member.

7. The manufacturing method as described in claim 6, wherein, In the covering process, a cover component with an opening is used. The cover member covers the upper surface of the external conductive member in such a way that the inner edge of the opening overlaps with the conical surface.

8. The manufacturing method as described in claim 6 or 7, wherein, The ratio (W2 / W1) of the shortest distance W1 to the shortest distance W2 from the junction of the conical surface and the bottom surface to the outer periphery of the concave portion when viewed from above is greater than 0.

4.

9. A method for manufacturing a battery pack in which multiple individual cells are interconnected via busbars, wherein, include: A secondary battery, which is the single cell, is manufactured using the manufacturing method according to any one of claims 1 to 8; as well as The busbar is disposed on the upper surface of the external conductive member, and the external conductive member is connected to the busbar.

10. A secondary battery, comprising: An electrode body, the electrode body comprising a positive electrode and a negative electrode; A battery casing that houses the electrode body; Terminals, which are electrically connected to the positive or negative terminal and are mounted on the battery casing; and An external conductive component, wherein the external conductive component is joined to the terminal outside the battery casing, wherein... The external conductive component has a through hole. A portion of the terminal is disposed within the through hole. Around the through hole, The external conductive component is provided with a junction with the terminal. The external conductive member is provided with a generally annular recess that extends from the upper surface of the external conductive member. When viewed from above, the shortest distance W1 from the periphery of the through hole to the outer periphery of the recess is greater than 2 mm.

11. The secondary battery as claimed in claim 10, wherein, The inner wall surface of the recess is a conical surface that extends from the bottom of the recess to the upper surface of the external conductive member.

12. The secondary battery as claimed in claim 11, wherein, The ratio (W2 / W1) of the shortest distance W1 to the shortest distance W2 from the junction of the conical surface and the bottom surface to the outer periphery of the concave portion when viewed from above is greater than 0.

4.

13. The secondary battery according to any one of claims 10 to 12, wherein, It is equipped with a current collector that electrically connects the positive or negative electrode to the terminal. A fusible link is formed in the current collector. When a current of 1000A or more flows through the secondary battery, the fuse melts.

14. A battery pack in which multiple individual cells are electrically connected to each other via busbars, wherein, As the single battery, there is a secondary battery as described in any one of claims 10 to 13. The busbar is disposed on the upper surface of the external conductive member, and the individual cells are connected to each other via the busbar.

15. The battery pack of claim 14, wherein, The manifold covers the through hole and the recess.

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