Energy storage device and method for manufacturing the same

Abstract

To provide a highly reliable energy storage device and a method for manufacturing the same. [Solution] The energy storage device comprises a first conductive member, a second conductive member connected to the first conductive member, a first electrode terminal electrically connected to the second conductive member and provided on a first sealing plate, a base portion disposed between the second conductive member and the first sealing plate, and a first insulating member formed on the outer periphery of the base portion and including an outer peripheral wall rising in a direction intersecting the extending direction of the base portion. A welded portion is formed where the first conductive member and the second conductive member are welded together. The outer periphery of the base portion includes a first portion located near the welded portion and a second portion other than the first portion, wherein the first portion does not have an outer peripheral wall, or the maximum height of the outer peripheral wall in the first portion is lower than the maximum height of the outer peripheral wall in the second portion.

Description

Technical Field

[0001] This technology relates to a power storage device and a method for manufacturing the same.

Background Art

[0002] Japanese Patent No. 4537353 (Patent Document 1) discloses a rectangular secondary battery in which an electrode group (25) is housed in a case (14) having openings (14a, 14b) at both ends, and electrode terminals (21, 23) are attached to cap plates (33, 33') that seal the openings (14a, 14b).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power storage device, an insulating member is provided to ensure electrical insulation at a predetermined position. It is required to enhance the reliability of ensuring insulation by the insulating member. From this perspective, there is still room for improvement in the battery described in Japanese Patent No. 4537353.

[0005] An object of this technology is to provide a highly reliable power storage device and a method for manufacturing the same.

Means for Solving the Problems

[0006] This technology provides the following power storage device and a method for manufacturing the same.

[0007] [1] An electrode body including a first electrode and a second electrode having a different polarity from the first electrode; a case housing the electrode body, including a case body having a first opening and a first sealing plate that seals the first opening; a first conductive member; a second conductive member connected to the first conductive member; a first electrode terminal electrically connected to the second conductive member and provided on the first sealing plate; a base portion disposed between the second conductive member and the first sealing plate; and a first insulating member formed on the outer periphery of the base portion, including an outer periphery wall rising in a direction intersecting the extending direction of the base portion, wherein a welded portion is formed where the first conductive member and the second conductive member are welded together; the outer periphery of the base portion includes a first portion located near the welded portion and a second portion other than the first portion, the first portion does not have the outer periphery wall formed on it, or the maximum height of the outer periphery wall in the first portion is lower than the maximum height of the outer periphery wall in the second portion.

[0008] [2] The energy storage device according to [1], wherein the first conductive member includes a first plate-like portion, the first plate-like portion having a pair of first main surfaces facing each other and a first side end surface connecting the pair of first main surfaces, the second conductive member includes a second plate-like portion, the second plate-like portion having a pair of second main surfaces facing each other and a second side end surface connecting the pair of second main surfaces, the first conductive member and the second conductive member are arranged such that one of the pair of first main surfaces and one of the pair of second main surfaces abut each other, and the welded portion is formed on the first side end surface and the second side end surface.

[0009] [3] The energy storage device according to [1] or [2], wherein the first conductive member includes a first region and a second region, the second conductive member includes a third region and a fourth region, a second insulating member is disposed between the first region and the third region, and the second region and the fourth region are in contact.

[0010] [4] The outer peripheral edge of the base portion includes a pair of first end edges facing each other and a pair of second end edges extending in a direction intersecting the first end edges and facing each other, wherein the outer peripheral wall is provided on each of the pair of first end edges, the outer peripheral wall is provided on one of the pair of second end edges, and the first portion is included on the other of the pair of second end edges, the energy storage device according to any one of [1] to [3].

[0011] [5] The energy storage device according to any one of [1] to [4], wherein, when viewed from a direction perpendicular to the extending direction of the base portion, the outer peripheral edge of the base portion protrudes more than the second conductive member, and the amount of protrusion (W1) of the outer peripheral edge of the base portion in the first portion is greater than the amount of protrusion (W2) of the outer peripheral edge of the base portion in the second portion.

[0012] [6] A method for manufacturing an energy storage device comprising an electrode body including a first electrode, a second electrode having a different polarity from the first electrode, and a first electrode tab electrically connected to the first electrode; a case for housing the electrode body, including a case body having a first opening and a first sealing plate that seals the first opening; a first conductive member electrically connected to the first electrode tab; a second conductive member connected to the first conductive member; a first electrode terminal electrically connected to the second conductive member and provided on the first sealing plate; a base portion disposed between the second conductive member and the first sealing plate; and a first insulating member formed on the outer periphery of the base portion and including an outer periphery wall rising in a direction intersecting the extending direction of the base portion, wherein the electrode body is inserted into the case body. A method for manufacturing an energy storage device, comprising the steps of: inserting the electrode body into the case body, and then joining a first conductive member electrically connected to the first electrode via the first electrode tab and a second conductive member, wherein the step of joining the first conductive member and the second conductive member includes irradiating at least one of the first conductive member and the second conductive member with an energy ray and welding the first conductive member and the second conductive member to form a welded portion, the outer periphery of the base portion includes a first portion located near the welded portion and a second portion other than the first portion, the first portion does not have the outer periphery wall formed on it, or the maximum height of the outer periphery wall in the first portion is lower than the maximum height of the outer periphery wall in the second portion.

[0013] [7] The method for manufacturing an energy storage device according to [6], wherein, before joining the first conductive member and the second conductive member, the second conductive member is electrically connected to the first electrode terminal, and the step of joining the first conductive member and the second conductive member is to irradiate at least one of the first conductive member and the second conductive member with an energy ray from between the case body and the first sealing plate, and weld the first conductive member and the second conductive member. [Effects of the Invention]

[0014] This technology makes it possible to provide a highly reliable energy storage device and a method for manufacturing the same.

Brief Description of the Drawings

[0015] [Figure 1] It is a front view showing the configuration of the secondary battery according to the embodiment. [Figure 2] It is a view showing the state of the secondary battery shown in FIG. 1 as seen from the direction of arrow II. [Figure 3] It is a view showing the state of the secondary battery shown in FIG. 1 as seen from the direction of arrow III. [Figure 4] It is a view showing the state of the secondary battery shown in FIG. 1 as seen from the direction of arrow IV. [Figure 5] It is a view showing the state of the secondary battery shown in FIG. 1 as seen from the direction of arrow V. [Figure 6] It is a front cross-sectional view of the secondary battery shown in FIG. 1. [Figure 7] It is a cross-sectional view of the negative electrode plate. [Figure 8] It is a front view showing the negative electrode plate. [Figure 9] It is a cross-sectional view of the positive electrode plate. [Figure 10] It is a front view showing the positive electrode plate. [Figure 11] It is an XI-XI cross-sectional view of the secondary battery shown in FIG. 1. [Figure 12] It is an XII-XII cross-sectional view of the secondary battery shown in FIG. 1. [Figure 13] It is a flowchart showing a method for manufacturing a secondary battery according to one embodiment. [Figure 14] It is a perspective view showing the state before two electrode bodies included in the secondary battery according to one embodiment overlap. [Figure 15] It is an XV-XV cross-sectional view of the electrode body and the current collector shown in FIG. 14. [Figure 16] It is a perspective view showing the state in which a holder and a spacer are attached to the electrode body. [Figure 17] It is a perspective view showing the state in which a sealing plate is attached to the current collector on the negative electrode side. [Figure 18] It is an XVIII-XVIII cross-sectional view of the electrode body and the current collector shown in FIG. 17. [Figure 19] This is a perspective view showing the positive electrode current collector with a sealing plate attached. [Figure 20] This is a perspective view showing the configuration of a secondary battery. [Figure 21] This is a perspective view showing the current collection structure on the positive electrode side before the conductive members are joined together. [Figure 22] This is a cross-sectional view of section XXII-XXII in Figure 21. [Figure 23] This is a cross-sectional view showing the junction after irradiation with energy rays. [Figure 24] This is a front view of the insulating material. [Figure 25] This is a perspective view (part 1) of the insulating material. [Figure 26] This is a perspective view (part 2) of the insulating material. [Figure 27] This is a perspective view (part 3) of the insulating material. [Figure 28] This is a front view showing the conductive member attached to the insulating member. [Figure 29] This is a perspective view showing the conductive member attached to the insulating member. [Figure 30] This is a side view showing the conductive member attached to the insulating member. [Figure 31] This is an enlarged view showing one end of the insulating material. [Figure 32] This is an enlarged view showing the other end of the insulating material. [Figure 33] This is a diagram (part 1) showing the formation process of the joint of conductive members in a positive electrode current collection structure. [Figure 34] This is a diagram (part 2) showing the formation process of the joint of conductive members in a positive electrode current collection structure. [Figure 35] This is a diagram (part 3) showing the formation process of the joint of conductive members in a positive electrode current collection structure. [Figure 36] This is a diagram (part 4) showing the formation process of the joint of conductive members in a positive electrode current collection structure. [Modes for carrying out the invention]

[0016] Embodiments of this technology are described below. Note that the same or corresponding parts may be denoted by the same reference numerals, and their descriptions may not be repeated.

[0017] In the embodiments described below, when referring to the number, quantity, etc., unless otherwise specified, the scope of this technology is not necessarily limited to that number, quantity, etc. Also, in the embodiments described below, each component is not necessarily essential to this technology unless otherwise specified. Furthermore, this technology is not necessarily limited to achieving all of the effects and advantages mentioned in these embodiments.

[0018] In this specification, the terms "comprise," "include," and "have" are in open-ended form. That is, if a configuration includes one configuration, it may also include other configurations, or it may not.

[0019] Furthermore, where geometric terms and terms describing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° oblique," "coaxial," and "alongside," these terms allow for manufacturing tolerances or slight variations. Where terms describing relative positional relationships, such as "upper" and "lower," are used in this specification, these terms are used to indicate the relative positional relationship in a single state, and the relative positional relationship may be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by inverting the entire mechanism upside down).

[0020] Furthermore, the dimensions of each component illustrated in this specification, such as width, length, and diameter, are not limited to those shown and may be changed as appropriate. In this specification, each component may be assigned an ordinal number such as "1st" or "2nd," but these ordinal numbers do not limit priority, order, etc., unless explicitly specified.

[0021] In this specification, "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "electrode" may refer collectively to the positive electrode and the negative electrode. Also, "electrode plate" may refer collectively to the positive electrode plate and the negative electrode plate.

[0022] In this specification, when the terms “energy storage device,” “energy storage cell,” or “energy storage module” are used, “energy storage device,” “energy storage cell,” or “energy storage module” are not limited to batteries, battery cells, or battery modules, but may include capacitors, capacitor cells, or capacitor modules.

[0023] "Battery cells" can be installed in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of "battery cells" is not limited to automotive applications.

[0024] In this specification, the X direction may be referred to as the "width direction" of the secondary battery, electrode body, and case body, the Z direction may be referred to as the "height direction" of the secondary battery or case body, and the Y direction may be referred to as the "thickness direction" of the secondary battery or case body.

[0025] (Overall configuration of a secondary battery) The overall configuration of the secondary battery 1 will be described with reference to Figures 1 to 6. The secondary battery 1 includes a case 100, an electrode body 200, electrode terminals 300, and a current collector 400. The case 100 includes a case body 110, a sealing plate 120, and a sealing plate 130.

[0026] When a battery pack including a secondary battery 1 is constructed, multiple secondary batteries 1 are stacked in the thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y direction) by a restraining member to form a battery module, or the battery pack may be directly supported on the side of the battery pack case without using a restraining member.

[0027] The case body 110 consists of a cylindrical, preferably rectangular, member. This results in a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, aluminum alloy, iron, or iron alloy.

[0028] As shown in Figures 1 and 2, sealing plates 120 and 130 are provided at both ends of the case body, respectively. The case body 110 can be formed into a rectangular tube shape by, for example, bringing together the ends of bent plate-shaped members (joint portion 115 as illustrated in Figure 2) and joining them together (for example, by energy ray irradiation such as laser welding). The corners of the "rectangular tube" may have a rounded shape. The secondary battery in this technology is not necessarily limited to a rectangular secondary battery.

[0029] In this embodiment, the case body 110 is formed to be longer in the width direction (X direction) of the secondary battery 1 than in the thickness direction (Y direction) and height direction (Z direction) of the secondary battery 1. The dimension (width) of the case body 110 in the X direction is preferably about 30 cm or more. This makes it possible to construct a relatively large (high capacity) secondary battery 1. The dimension (height) of the case body 110 in the Z direction is preferably about 20 cm or less, more preferably about 15 cm or less, and even more preferably about 10 cm or less. This makes it possible to construct a relatively low-height secondary battery 1, which improves, for example, its mountability in a vehicle.

[0030] The case body 110 includes a pair of first side sections 111 and a pair of second side sections 112. The pair of first side sections 111 constitute a part of the side surface of the case 100. The pair of second side sections 112 constitute the bottom and top surfaces of the case 100. Each of the pair of first side sections 111 and the pair of second side sections 112 is provided so as to intersect each other. The pair of first side sections 111 and the pair of second side sections 112 are connected at their respective ends. It is desirable that each of the pair of first side sections 111 has a larger area than each of the pair of second side sections 112.

[0031] As shown in Figure 5, a gas exhaust valve 150 is provided on one of the pair of second side portions 112A. The gas exhaust valve 150 extends in the width direction (X direction) of the secondary battery 1. The gas exhaust valve 150 extends in the X direction to the extent that it does not reach the ends of the case body 110 from the center in the X direction. The shape of the gas exhaust valve 150 can be changed as appropriate.

[0032] The thickness of the plate-shaped member in the gas discharge valve 150 is thinner than the thickness of the other plate-shaped members in the case body 110. As a result, when the pressure inside the case 100 exceeds a predetermined value, the gas discharge valve 150 preferentially ruptures compared to other parts of the case body 110, and discharges the gas inside the case 100 to the outside.

[0033] As shown in Figure 2, a joint portion 115 is formed on the other second side portion 112B of the pair of second side portions 112. The joint portion 115 extends in the width direction (X direction) of the secondary battery 1. At the joint portion 115, the ends of the plate-shaped members constituting the case body 110 are joined together.

[0034] As shown in Figure 3, an opening 113 (second opening) is provided at one end of the case body 110 in the first direction (X direction). The opening 113 is sealed by a sealing plate 120 (second sealing plate). A joint 115 is formed in the opening 113 to seal it. The opening 113 and the sealing plate 120 have a substantially rectangular shape with the Y direction being the short side and the Z direction being the long side. The substantially rectangular shape includes a rectangular shape, or a rectangular shape with rounded corners, etc.

[0035] A negative electrode terminal 301 (second electrode terminal) is provided on the sealing plate 120. The position of the negative electrode terminal 301 can be changed as appropriate.

[0036] As shown in Figure 4, an opening 114 (first opening) is provided at the end of the case body 110 opposite to the first side in the X direction. That is, the opening 114 is located at the end opposite to the opening 113, and the openings 113 and 114 face each other. The opening 114 is sealed by a sealing plate 130 (first sealing plate). A joint 115 is formed in the opening 114 to seal it. The opening 114 and the sealing plate 130 have a substantially rectangular shape with the Y direction being the short side and the Z direction being the long side.

[0037] A positive electrode terminal 302 (first electrode terminal) and an electrolyte injection hole 134 are provided on the sealing plate 130. The electrolyte injection hole 134 only needs to be large enough to inject electrolyte into the case 100, and is preferably smaller than the insertion hole for the positive electrode terminal 302 provided on the sealing plate 130. It is preferable that the electrolyte injection hole 134 is offset from the center of the sealing plate 130 in the Z direction. The positions of the positive electrode terminal 302 and the electrolyte injection hole 134 can be changed as appropriate.

[0038] The form of the positive terminal 302 provided on the sealing plate 130 includes both cases in which the positive terminal 302 is arranged on the sealing plate 130 via an insulating material or the like, and cases in which the positive terminal 302 is arranged directly on the sealing plate 130.

[0039] The sealing plates 120 and 130 are made of metal. Specifically, the sealing plates 120 and 130 are made of aluminum, aluminum alloy, iron, or iron alloy.

[0040] The negative electrode terminal 301 is electrically connected to the negative electrode (second electrode) of the electrode body 200. The negative electrode terminal 301 is attached to the sealing plate 120, i.e., the case 100.

[0041] The positive terminal 302 is electrically connected to the positive electrode (first electrode) of the electrode body 200. The positive terminal 302 is attached to the sealing plate 130, i.e., the case 100.

[0042] The negative electrode terminal 301 is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 301.

[0043] The positive terminal 302 is made of a conductive material (more specifically, a metal), which may be made of aluminum or an aluminum alloy, for example.

[0044] The injection hole 134 is sealed by a sealing member (not shown). For example, a blind rivet or other metal member can be used as the sealing member.

[0045] The electrode body 200 is a flat-shaped electrode body in which negative electrode plates and positive electrode plates, described later, are stacked. Specifically, the electrode body 200 is a laminated electrode body in which a plurality of negative electrode plates and a plurality of positive electrode plates are alternately stacked with a separator in between. The separator may be a strip-shaped insulating sheet member folded in a zigzag pattern, or it may be a plurality of separate insulating sheets provided individually. In this specification, "electrode body" is not limited to a laminated electrode body, and may also be a wound electrode body in which a strip-shaped negative electrode plate and a strip-shaped positive electrode plate are wound together with a strip-shaped separator in between. The separator can be made of, for example, a polyolefin microporous film. When the electrode body is a laminated electrode body including a plurality of negative electrode plates and a plurality of positive electrode plates, negative electrode tabs (second electrode tabs) provided on each negative electrode plate can be stacked to form a negative electrode tab group, and positive electrode tabs (first electrode tabs) provided on each positive electrode plate can be stacked to form a positive electrode tab group.

[0046] As shown in Figure 6, the case 100 houses the electrode body 200. In Figure 6, the first electrode body 201, which will be described later, is shown as an example. The first electrode body 201 is housed in the case 100 so that its longitudinal direction is parallel to the X direction.

[0047] Specifically, one or more laminated electrode bodies are housed inside the insulating sheet 700 (described later) placed within the case 100, together with an electrolyte (not shown). As the electrolyte (non-aqueous electrolyte), for example, a non-aqueous solvent prepared by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio (25°C) of 30:30:40, in which LiPF6 is dissolved at a concentration of 1.2 mol / L can be used. A solid electrolyte may be used instead of an electrolyte.

[0048] The electrode body 200 includes a first electrode body 201. The first electrode body 201 includes a substantially rectangular main body, a negative electrode tab group 220, and a positive electrode tab group 250.

[0049] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240, which will be described later. The negative electrode tab group 220 is located at one end (sealing plate 120 side) of the first electrode body 201 in the X direction relative to the main body. The positive electrode tab group 250 is located at the other end (sealing plate 130 side) of the first electrode body 201 in the X direction relative to the main body.

[0050] The negative electrode tab group 220 and the positive electrode tab group 250 are formed to protrude from the central portion of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0051] The current collector 400 includes a negative electrode current collector 400A and a positive electrode current collector 400B. The negative electrode current collector 400A and the positive electrode current collector 400B are each made of plate-shaped members. The electrode body 200 is electrically connected to the negative electrode terminal 301 and the positive electrode terminal 302 via the current collector 400.

[0052] The negative electrode current collector 400A is positioned on the sealing plate 120 via a resin insulating member. The negative electrode current collector 400A is electrically connected to the negative electrode tab group 220 and the negative electrode terminal 301. The negative electrode current collector 400A is made of a conductive material (more specifically, a metal), which may be made of copper or a copper alloy, for example. Details of the negative electrode current collector 400A will be described later.

[0053] The positive electrode current collector 400B is positioned on the sealing plate 130 via a resin insulating member. The positive electrode current collector 400B is electrically connected to the positive electrode tab group 250 and the positive electrode terminal 302. The positive electrode current collector 400B is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy. The positive electrode tab group 250 may be electrically connected to the sealing plate 130 directly or via the positive electrode current collector 400B. In this case, the sealing plate 130 may also function as the positive electrode terminal 302. Details of the positive electrode current collector 400B will be described later.

[0054] (Configuration of electrode body 200) As shown in Figures 7 and 8, the negative electrode plate 210 has a different polarity from the positive electrode plate 240. A negative electrode tab 230, consisting of a negative electrode core 211, is provided at one end of the negative electrode plate 210 in the width direction. When the negative electrode plates 210 are stacked, multiple negative electrode tabs 230 are stacked to form a negative electrode tab group 220. The length of each negative electrode tab 230 in the protruding direction of the multiple negative electrode plates 210 is appropriately adjusted considering the state in which the negative electrode tab group 220 is connected to the negative electrode current collector 400A. The shape of the negative electrode tab 230 is not limited to that illustrated in Figure 8.

[0055] As shown in Figures 9 and 10, a positive electrode tab 260, consisting of a positive electrode core 241, is provided at one end in the width direction of the molded positive electrode plate 240. When the positive electrode plates 240 are stacked, multiple positive electrode tabs 260 are stacked to form a group of positive electrode tabs 250. The length of each positive electrode tab 260 in the protruding direction on the multiple positive electrode plates 240 is appropriately adjusted considering the state in which the group of positive electrode tabs 250 is connected to the positive electrode current collector 400B. The shape of the positive electrode tab 260 is not limited to that illustrated in Figure 10.

[0056] A positive electrode protective layer 243 is provided at the base of the positive electrode tab 260. However, the positive electrode protective layer 243 is not necessarily provided at the base of the positive electrode tab 260.

[0057] In a typical example, the thickness of one negative electrode tab 230 is less than the thickness of one positive electrode tab 260. In this case, the thickness of the negative electrode tab group 220 is less than the thickness of the positive electrode tab group 250.

[0058] (Connection structure between electrode body 200 and current collector 400) The connection structure between the electrode body 200 and the current collector 400 will be described with reference to Figures 11 and 12.

[0059] As shown in Figures 11 and 12, the electrode body 200 includes a first electrode body 201 and a second electrode body 202. Each of the first electrode body 201 and the second electrode body 202 includes a positive electrode and a negative electrode. The electrode body 200 may be composed of three or more electrode bodies.

[0060] The electrode body 200 is formed by stacking a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 are aligned in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0061] As shown in Figure 11 (connection structure on the negative electrode side), the first electrode body 201 includes a group of negative electrode tabs 220. The group of negative electrode tabs 220 is electrically connected to the current collector 410 (negative electrode current collector) at its first end 205 in the X direction. The second electrode body 202 includes a group of negative electrode tabs 270. The group of negative electrode tabs 270 is electrically connected to the current collector 410 (negative electrode current collector) at its third end 207 in the X direction.

[0062] The negative electrode tab group 220 has a curved portion 221 and a tip portion 222. The curved portion 221 is the part of the negative electrode tab group 220 that is curved. The tip portion 222 is the part located at the end of the negative electrode tab group 220.

[0063] The negative electrode tab group 220 has a first recess 220R that recesses towards the negative electrode tab group 270 when it is curved. The negative electrode tab group 270 has a second recess 270R that recesses towards the negative electrode tab group 220 when it is curved.

[0064] The negative electrode tab group 270 has a curved portion 271 and a tip portion 272. The curved portion 271 is the part of the negative electrode tab group 270 that is curved. The tip portion 272 is the part located at the end of the negative electrode tab group 270.

[0065] Each of the negative electrode tab group 220 and negative electrode tab group 270 is curved in opposite directions such that their tips 222 and 272 are closer together. In this embodiment, the tips 222 and 272 are spaced apart, but the configuration is not limited to this, and the tips 222 and 272 may be in contact with each other.

[0066] The negative electrode current collector 400A electrically connects the negative electrode terminal 301 to the negative electrode tab group 220 and the negative electrode tab group 270. In this embodiment, the negative electrode current collector 400A is connected to the negative electrode terminal 301 between the electrode body 200 and the sealing plate 120. The negative electrode current collector 400A includes current collectors 410 and 430.

[0067] The current collector 410 is a plate-shaped member. The current collector 410 has a longitudinal direction in the Z direction and a short direction in the Y direction. The current collector 410 is made up of a single, integrated part. The current collector 430 is a plate-shaped member. The current collector 430 has a longitudinal direction in the Z direction and a short direction in the Y direction. The current collectors 410 and 430 are arranged in parallel in the X direction. Thus, the current collectors 410 and 430 are made up of separate parts.

[0068] The negative electrode tab groups 220 and 270 are joined to the current collector 410 at a joint 411, which will be described later (see Figure 15). The joint 411 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, crimping, etc. In this embodiment, the negative electrode tab groups 220 and 270 and the current collector 410 are joined by, for example, ultrasonic welding.

[0069] The current collector 430 is joined to the current collector 410 at a joint located at its Z-direction end. The current collector 430 is connected to the negative terminal 301. The connection between the current collector 430 and the negative terminal 301 can be formed, for example, by crimping and / or welding.

[0070] The negative electrode terminal 301 is exposed to the outside of the sealing plate 120. The negative electrode terminal 301 is connected to the plate-shaped member 303. The negative electrode terminal 301 includes a region 301A made of copper or a copper alloy and a region 301B made of aluminum or an aluminum alloy, and it is preferable that the region 301A made of copper or a copper alloy is connected to the current collector 430.

[0071] The plate-shaped member 303 is located on the outside of the sealing plate 120. The plate-shaped member 303 is arranged along the sealing plate 120. The plate-shaped member 303 is electrically conductive. The plate-shaped member 303 is arranged to secure connection area with busbars, etc., that electrically connect the secondary battery 1 to other adjacent secondary batteries. The connection between the negative electrode terminal 301 and the plate-shaped member 303 can be formed, for example, by laser welding.

[0072] An insulating member 510 is placed between the plate-shaped member 303 and the sealing plate 120. An insulating member 520 is placed between the negative terminal 301 and the sealing plate 120. An insulating member 530 is placed between the current collector 430 and the sealing plate 120.

[0073] However, the negative terminal 301 may be electrically connected to the sealing plate 120. The sealing plate 120 may also serve as the negative terminal 301.

[0074] A spacer 600 is positioned between the sealing plate 120 and the main body of the electrode body 200 (excluding the negative electrode tab groups 220 and 270). The spacer 600 is made of an insulating resin material. The spacer 600 suppresses the movement of the electrode body 200 within the case 100 in the X direction, thereby suppressing damage to the negative electrode tab group 220, the negative electrode tab group 270, and the electrode body 200. The protrusions on the spacer 600 are positioned within the first recess 220R and the second recess 270R.

[0075] As shown in Figure 12 (connection structure on the positive electrode side), the connection structure between the electrode body 200 and the current collector 400 on the positive electrode side differs from the configuration on the negative electrode side in that the part corresponding to the current collector 410 on the negative electrode side is composed of two parts.

[0076] The first electrode body 201 includes a group of positive electrode tabs 250. The group of positive electrode tabs 250 is electrically connected to the current collector 420 (positive electrode current collector) at a second end 206 in the X direction. The second electrode body 202 includes a group of positive electrode tabs 280. The group of positive electrode tabs 280 is electrically connected to the current collector 420 at a fourth end 208 in the X direction.

[0077] The positive electrode tab group 250 has a curved portion 251 and a tip portion 252. The curved portion 251 is the part of the positive electrode tab group 250 that is curved. The tip portion 252 is the part located at the end of the positive electrode tab group 250.

[0078] The positive electrode tab group 250 has a first recess 250R that recesses toward the positive electrode tab group 280 when curved. The positive electrode tab group 280 has a second recess 280R that recesses toward the positive electrode tab group 250 when curved. The protrusions provided on the spacer 600 are positioned within the first recess 250R and the second recess 280R.

[0079] The positive electrode tab group 280 has a curved portion 281 and a tip portion 282. The curved portion 281 is the part of the positive electrode tab group 280 that is curved. The tip portion 282 is the part located at the end of the positive electrode tab group 280.

[0080] Each of the positive electrode tab group 250 and the positive electrode tab group 280 is curved in opposite directions such that their tips 252 and 282 are closer together. In this embodiment, the tips 252 and 272 are spaced apart, but the configuration is not limited to this, and the tips 252 and 282 may be in contact with each other.

[0081] The positive electrode current collector 400B electrically connects the positive electrode terminal 302 to the positive electrode tab group 250 and the positive electrode tab group 280. In this embodiment, the positive electrode current collector 400B is connected to the positive electrode terminal 302 between the electrode body 200 and the sealing plate 130.

[0082] The positive electrode current collector 400B includes a current collector 420 and a current collector 440. An insulating member 460 is interposed between the current collector 420 and the current collector 440, but the two are electrically joined at a position different from the cross-section shown in the figure.

[0083] The current collector 420 is a plate-shaped member. The current collector 420 has a longitudinal direction in the Z direction and a short direction in the Y direction. The current collector 420 is composed of one current collector and another current collector. That is, the current collector 420 is composed of two parts.

[0084] The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420, which is composed of two parts, at a joint 421 (see Figure 15), which will be described later. The joint 421 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, crimping, etc. In this embodiment, the positive electrode tab group 250 and the positive electrode tab group 280 and the current collector 420 are joined by, for example, ultrasonic welding.

[0085] The current collector 440 is joined to the current collector 420 at a joint located at its Z-direction end. The current collector 440 is connected to the positive terminal 302. The connection between the current collector 440 and the positive terminal 302 can be formed, for example, by crimping and / or welding.

[0086] The positive terminal 302 is exposed on the outside of the sealing plate 130 and is positioned to reach the current collector 440 of the positive current collector 400B, which is located on the inner surface side of the sealing plate 130. The positive terminal 302 is connected to the plate-shaped member 304.

[0087] The plate-shaped member 304 is located on the outside of the sealing plate 130. The plate-shaped member 304 is arranged along the sealing plate 130. The plate-shaped member 304 is electrically conductive. The plate-shaped member 304 is positioned to secure connection area with busbars, etc., that electrically connect the secondary battery 1 to other adjacent secondary batteries. The connection between the positive electrode terminal 302 and the plate-shaped member 304 can be formed, for example, by laser welding.

[0088] An insulating member 510 is placed between the plate-shaped member 304 and the sealing plate 130. An insulating member 520 is placed between the positive terminal 302 and the sealing plate 130. An insulating member 470 is placed between the current collector 440 and the sealing plate 130.

[0089] However, the positive terminal 302 may be electrically connected to the sealing plate 130. The sealing plate 130 may also serve the role of the positive terminal 302.

[0090] A spacer 600 is positioned between the sealing plate 130 and the main body of the electrode body 200 (excluding the positive electrode tab groups 250 and 280). The spacer 600 is made of an insulating resin material. The spacer 600 suppresses the movement of the electrode body 200 within the case 100 in the X direction, thereby suppressing damage to the positive electrode tab groups 250 and 280 and the electrode body 200.

[0091] The spacer 600 shown in Figures 11 and 12 is made of, for example, resin. The material of the spacer 600 may be, for example, polypropylene (PP), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), or ethylene propylene diene rubber (EPDM).

[0092] As shown in Figures 11 and 12, a resin insulating sheet 700 (electrode holder) is placed between the electrode body 200 and the case body 110. The insulating sheet 700 can be made of, for example, resin. More specifically, the material of the insulating sheet 700 may be, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0093] (Manufacturing process for secondary battery 1) The method for manufacturing a secondary battery according to this embodiment will be described below using the flowchart in Figure 13. In the method for manufacturing a secondary battery according to this embodiment, first, the first electrode body 201 and the second electrode body 202 are manufactured (step S1). It is preferable that a portion of the tip of each of the negative electrode tab group 220, positive electrode tab group 250, negative electrode tab group 270, and positive electrode tab group 280 is cut so that when the tips are bundled together they are the same length.

[0094] As shown in Figures 14 and 15, after the first electrode body 201 and the second electrode body 202 are fabricated, the positive electrode tab groups 250 and 280 are joined to the current collector 420 (step S2). The positive electrode tab groups 250 and 280 are joined to the current collector 420 at the joining point 421.

[0095] Next, the first electrode body 201, the current collector 410, and the second electrode body 202 are arranged in this order in the DR1 direction. The negative electrode tab group 220 is placed on one side of the current collector 410 in the DR1 direction. With the negative electrode tab group 270 placed on the other side of the current collector 410 in the DR1 direction, the negative electrode tab group 220 and the negative electrode tab group 270 are joined to the current collector 410 (step S3). The negative electrode tab group 220 and the negative electrode tab group 270 are joined to the current collector 410 at the joining point 411.

[0096] In the height direction of the first electrode body 201 and the second electrode body 202, the current collectors 410 and 420 are positioned off-center to one side of the center of the first electrode body 201 and the second electrode body 202. This allows the current collectors to be made shorter, thus enabling them to be made smaller. The current collectors 410 and 420 are not limited to this configuration. The current collectors 410 and 420 may be positioned in the center of the first electrode body 201 and the second electrode body 202 in the height direction of the first electrode body 201 and the second electrode body 202.

[0097] The order in which the current collectors 410 and 420 are joined to the first electrode body 201 and the second electrode body 202 is not limited to the above, and the order may be changed. The step of joining the current collectors 420 to the first electrode body 201 and the second electrode body 202 is preferably performed before the step of overlapping the first electrode body 201 and the second electrode body 202, which will be described later, and is preferably performed before the step of joining the current collector 410 to the first electrode body 201 and the second electrode body 202.

[0098] Next, after joining the negative electrode tab group 220 and the negative electrode tab group 270 to the current collector 410, the negative electrode tab group 220 and the negative electrode tab group 270 are bent in the thickness direction of the first electrode body 201 and the second electrode body 202 (in the direction perpendicular to the DR1 direction in Figures 17 and 18) to overlap the first electrode body 201 and the second electrode body 202 (step S4). In other words, the first electrode body 201 and the second electrode body 202 are brought together.

[0099] "Overlapping the first electrode and the second electrode" means that the first electrode and the second electrode may be directly overlapped, or other components may be placed between the first electrode and the second electrode. The first electrode and the second electrode may or may not be fixed with tape or the like. Furthermore, the first electrode, the current collector and the second electrode do not have to be arranged in a straight line in the DR1 direction, and the first electrode or the second electrode may be inclined with respect to the current collector in the DR1 direction.

[0100] The negative electrode tab group 220 and the negative electrode tab group 270 are bent so that their tips face each other. The positive electrode tab group 250 and the positive electrode tab group 280 are also bent so that their tips face each other.

[0101] Next, as shown in Figure 16, the spacers 600 and insulating sheet 700 are assembled to the electrode body 200 (step S5). After assembling the spacers 600 to both the negative and positive electrode sides of the electrode body 200, the electrode body 200 and the spacers 600 on both sides are covered with the insulating sheet 700. In this way, with the spacers 600 positioned on both sides of the electrode body 200, the electrode body 200 and the spacers 600 on both sides are covered with the insulating sheet 700. The insulating sheet 700 is fixed to the spacers 600 on both sides.

[0102] Next, as shown in Figures 17 and 18, the current collector 410 is electrically connected to the negative terminal 301 via the current collector 430 (step S6). Step S6 can also be performed before step S5. Specifically, as shown in Figure 18, the negative tab group 220 and the negative tab group 270 are bent so that their tips 222 and 272 face each other.

[0103] The negative electrode terminal 301 and the current collector 430 are attached to the sealing plate 120 via an insulating member. The current collector 430 is brought into contact with the current collector 410 in the X direction. The connection of the plate-shaped member 303 to the negative electrode terminal 301 can be done at any time. The current collector 430 and the current collector 410 are joined by laser welding from between the sealing plate 120 and the insulating sheet 700.

[0104] Next, the spacer 600 and electrode body 200 are inserted into the case body 110 through the opening 113, with the current collector 420 side leading (step S7). Then, from the state in which the negative electrode tab group 220 and negative electrode tab group 270 are extended, the negative electrode tab group 220 and negative electrode tab group 270 are bent by bringing the sealing plate 120 and the main body of the electrode body 200 (first electrode body 201 and second electrode body 202) closer together (state shown in Figure 11). The negative electrode tab group 220 and negative electrode tab group 270 are bent along the shape of the spacer 600 so that the folded portions of the bent parts 221 and 271 are closer to the case body 110 in the Y direction.

[0105] As shown in Figure 19, after the sealing plate 120 is brought into contact with the case body 110, the sealing plate 120 is temporarily joined to the case body 110. This temporary joining partially joins the sealing plate 120 to the opening 113 of the case body 110. This positions the sealing plate 120 relative to the case body 110.

[0106] When inserting the electrode body 200 into the case body 110, the electrode body 200 may be pulled from the current collector 420 side or pushed from the current collector 410 side. When the electrode body 200 is pushed from the current collector 410 side, the negative electrode tab group 220 and the negative electrode tab group 270 can be bent at the same time.

[0107] After inserting the electrode body 200 into the case body 110, the current collector 420 is electrically connected to the positive terminal 302 (step S8). Specifically, the positive terminal 302 is attached to the sealing plate 130 via an insulating member. After inserting the first electrode body 201 and the second electrode body 202 into the case body 110, the current collector 440 is brought into contact with the current collector 420 protruding from the opening 114 in the X direction. The connection of the plate-shaped member 304 to the positive terminal 302 can be done at any time.

[0108] The positive electrode tab groups 250 and 280 connected to the current collector 420 are bent so that their tips 252 and 282 face each other. As shown in Figure 12, the positive electrode tab groups 250 and 280 are curved to conform to the shape of the spacer 600 so that the folded portions of the curved sections 251 and 281 approach the case body 110 in the Y direction.

[0109] After inserting the spacer 600 and electrode body 200 into the case body 110, the sealing plate 130 and sealing plate 120 are joined to the case body 110 (step S9).

[0110] As shown in Figure 20, after the sealing plate 130 is brought into contact with the case body 110, the sealing plate 130 is tack-welded to the case body 110. Through this tack-welding, the sealing plate 130 is partially joined to the opening 114 of the case body 110. This positions the sealing plate 130 relative to the case body 110.

[0111] Next, the sealing plates 120 and 130 are joined to the case body 110. Sealing plate 120 seals the opening 113 of the case body 110, and sealing plate 130 seals the opening 114 of the case body 110. As a result, the first electrode body 201 and the second electrode body 202 are housed in the case 100.

[0112] After the above process, inspections such as leak testing are performed (S10 process). After the leak testing, the secondary battery 1 is dried to remove moisture from inside the case 100.

[0113] Next, with the sealing plate 130 positioned above the sealing plate 120 in the vertical direction and the spacer 600 positioned below the electrode body 200, the electrolyte is injected into the case 100 through the injection hole 134 provided in the sealing plate 130 (step S11). Because the spacer 600 is provided around where the electrolyte is injected, damage to the electrode body 200 and other components is suppressed even if the electrolyte is injected forcefully into the case 100. As a result, the secondary battery 1 of this embodiment can inject the electrolyte in a shorter time compared to the case without the spacer 600. After that, degassing and charging are performed. During degassing and charging, the injection hole 134 may be temporarily sealed. After that, the injection hole 134 is sealed, and the secondary battery 1 is completed.

[0114] (Positive electrode current collection structure) As shown in Figures 21 and 22, the current collectors 420 and 440 are plate-shaped members having a longitudinal direction in the Z-axis direction and a short direction in the Y-axis direction. It is preferable to use aluminum or an aluminum alloy for the current collectors 420 and 440.

[0115] The current collector 420 (first conductive member) has a first region R1 and a second region R2. The current collector 440 (second conductive member) has a third region R3 and a fourth region R4. An insulating member 460 is placed between the first region R1 of the current collector 420 and the third region R3 of the current collector 440. An insulating member 470 is placed between the sealing plate 130 and the current collector 440.

[0116] In the direction perpendicular to the sealing plate 130 (X direction), the surface of the current collector 420 on the sealing plate 130 side of the second region R2 is positioned closer to the sealing plate 130 than the surface of the first region R1 on the sealing plate 130 side. The current collector 420 can be formed by bending.

[0117] A contact portion TR1 is provided between the second region R2 of the current collector 420 and the fourth region R4 of the current collector 440, where the second region R2 and the fourth region R4 come into contact. The current collector 420 and the current collector 440 are joined to each other at the upper end of the contact portion TR1.

[0118] As shown in Figures 21 and 22, before joining the current collector 420 and the current collector 440, the current collectors 420 and 440 each have a protrusion 420A (first protrusion) and a protrusion 440A (second protrusion) at the upper end of the contact portion TR1. In the example of Figures 21 and 22, the protrusions 420A and 440A are in contact with each other. However, a gap may be provided between the protrusions 420A and 440A. Alternatively, only one of the protrusions 420A or 440A may be provided.

[0119] By irradiating the protrusions 420A and 440A with energy rays, the current collectors 420 and 440 are joined to each other. Preferably, the current collectors 420 and 440 are joined by welding. More preferably, the current collectors 420 and 440 are joined by laser welding.

[0120] In the areas irradiated with energy rays, the height of protrusions 420A and 440A is reduced. In the areas irradiated with energy rays, protrusions 420A and 440A are almost completely eliminated, but in some cases, they may not be completely eliminated.

[0121] After inserting the electrode body 200 into the case body 110, during the joining process between the current collector 420 and the current collector 440, the above-mentioned energy ray (preferably laser light) is irradiated from between the case body 110 and the sealing plate 130 to at least one of the protrusions 420A of the current collector 420 and the protrusions 440A of the current collector 440. This forms the joint between the current collectors 420 and 440. Alternatively, the current collectors 420 and 440 may be joined before inserting the electrode body 200 into the case body 110.

[0122] The current collector 420 has an inclined portion T12 (stepped portion) between the first region R1 and the second region R2, and a gap S1 is provided between the inclined portion T12 and the current collector 440. This gap S1 gradually decreases toward the second region R2. Furthermore, the gap S1 has a region where the insulating member 460 is not placed. By providing the gap S1, it is possible to suppress the escape of heat generated when forming the joint between the current collectors 420 and 440 to the first region R1 and the third region R3, thereby enabling the stable formation of the joint between the current collectors 420 and 440, and reducing the heat transmitted to the positive electrode tab groups 250 and 280, the electrode body 200, and other conductive members.

[0123] The second region R2 (first plate-shaped portion) of the current collector 420 has a pair of opposing main surfaces (first main surfaces), and a protrusion 420A is formed on the upper end surface (first side end surface) connecting this pair of main surfaces. The fourth region R4 (second plate-shaped portion) of the current collector 440 has a pair of opposing main surfaces (second main surfaces), and a protrusion 440A is formed on the upper end surface (second side end surface) connecting this pair of main surfaces.

[0124] As shown in the examples in Figures 21 and 22, by irradiating the protrusions 420A and 440A provided at the upper ends of the current collectors 420 and 440 with energy rays to perform bonding, the heat generated by the irradiation of energy rays is concentrated around the protrusions 420A and 440A, making it possible to perform highly reliable bonding efficiently (with less energy). However, in the secondary battery 1 according to this embodiment, the shape of the bonding portion of the current collectors 420 and 440 is not particularly limited.

[0125] As shown in Figure 23, a joint 800 (welded portion) is formed to join the current collectors 420 and 440. The joint 800 is formed at the +Z side end of the current collectors 420 and 440, but the location of the joint 800 is not limited to this. Preferably, the center (deepest part) of the joint 800 coincides with the boundary (contact portion TR1) of the current collectors 420 and 440, as shown in Figure 23. However, the center of the joint 800 may be slightly shifted towards the current collector 420 side (-X side) or the current collector 440 side (+X side) from the state shown in Figure 23.

[0126] (Insulating member 470) As shown in Figures 24 to 27, the insulating member 470 (first insulating member) includes a base portion 470A and a through hole 470B. The base portion 470A is formed in a plate shape and is arranged along the sealing plate 130. Therefore, the base portion 470A extends along the YZ plane when the insulating member 470 is attached to the sealing plate 130. The base portion 470A is positioned between the current collector 440 and the sealing plate 130. The positive terminal 302 is inserted through the through hole 470B.

[0127] The base portion 470A has a roughly rectangular shape including a pair of long sides (first end sides) and a pair of short sides (second end sides). Here, "roughly rectangular shape" includes shapes with rounded corners and shapes in which notches are formed in part of the rectangle. The outer edge of the base portion 470A includes a first portion 471 (the short side on the +Z side) and a second portion 472 (the short side on the -Z side and a pair of long sides). However, "roughly rectangular shape" is not necessarily limited to having long sides and short sides, and includes "roughly square shape". Also, the shape of the base portion is not limited to "roughly rectangular shape".

[0128] Of the first part 471 and the second part 472, the first part 471 does not have an outer peripheral wall, while at least a portion of the second part 472 has outer peripheral walls 472A and 472B. The outer peripheral walls 472A and 472B are provided so as to rise from the base part 470A toward the electrode body 200 when the insulating member 470 is attached to the sealing plate 130. The first part 471 is positioned on the side where the joint 800 of the current collectors 420 and 440 is formed (in this embodiment, the +Z side).

[0129] A pair of outer peripheral walls 472A (first wall) are provided on a pair of long sides of the base portion 470A, and an outer peripheral wall 472B (second wall) is provided on the short side of the base portion 470A on the -Z side. However, depending on the location of the joint, the pair of outer peripheral walls 472A may be provided on the short side of the base portion 470A, and the outer peripheral wall 472B may be provided on the long side of the base portion 470A.

[0130] The outer perimeter wall 472A extends in the Z direction (height direction of the secondary battery 1) with the insulating member 470 attached to the sealing plate 130. The outer perimeter wall 472B extends in the Y direction (thickness direction of the secondary battery 1) with the insulating member 470 attached to the sealing plate 130.

[0131] As shown in Figures 24 to 27, it is preferable that the outer peripheral walls 472A and 472B are provided continuously so as to extend substantially over the entire length of the three sides of the substantially rectangular shape. However, the outer peripheral wall 472A may be provided only in a shorter and more limited area on the -Z side than as illustrated in Figures 24 to 27. Also, parts of the outer peripheral walls 472A and 472B may be provided intermittently.

[0132] In this embodiment, a joint portion 800 with the current collector 420 is formed on the upper side of the current collector 440, extending substantially over the entire length in the Y direction. Therefore, in the insulating member 470 illustrated here, the first portion 471 (the portion where the outer peripheral walls 472A and 472B are not formed) extends over the entire short side on the +Z side of the substantially rectangular shape when the insulating member 470 is attached to the sealing plate 130.

[0133] However, the first portion 471 only needs to be provided in the joint 800 formation area and its adjacent area (in this specification, these areas together are referred to as the "neighborhood" of the joint 800) when viewed from the +Z side (the side where the joint 800 is formed), and the arrangement of the first portion 471 can be changed according to the joint 800 formation area. For example, outer peripheral walls 472A and 472B may be provided on a part of the short side (top side) on the +Z side of the base portion 470A. In this case, the portion provided with outer peripheral walls 472A and 472B becomes the second portion 472. The above-mentioned "adjacent area" means the area from the edge of the joint 800 to a predetermined distance (at least 1 mm, more preferably at least 3 mm, and even more preferably 5 mm) when viewed from the +Z side (the side where the joint 800 is formed).

[0134] For example, if the base portion 470A of the insulating member 470 has a rectangular shape including four edges, one preferred embodiment is to provide the first portion 471 on the edge closest to the joint portion 800 among the four edges. In this case, the second portion 472 can be provided on the three edges other than the edge on which the first portion 471 is provided.

[0135] Depending on the formation area of ​​the joint 800, it is preferable that the first portion 471 is arranged over two or more sides of a substantially rectangular shape. For example, as shown in Figures 24 to 30, it is preferable that the first portion 471 is also provided at the two corner portions located at both ends of the short side (second end side) on the +Z side of the outer periphery of the base portion 470A where the first portion 471 is provided. It is also preferable that the first portion 471 is provided at the ends of a pair of long sides (first end sides) that connect to the two corner portions where the first portion 471 is provided. On the long side (first end side), it is preferable that the first portion 471 is provided so as to connect to the vicinity of the corner portion where the first portion 471 is provided. On the second end side (long side), the length of the area where the first portion 471 is provided is preferably about 0.5 mm or more, and more preferably about 1 mm or more. Furthermore, the length of the same area is preferably about 10 mm or less, and more preferably about 5 mm or less.

[0136] A projection 472C (fitting projection) is formed on the outer periphery wall 472A. The projection 472C is formed to protrude inward from the outer periphery wall 472A. The projection 472C can contribute to the positioning of the current collector 440 attached to the insulating member 470. However, the projection 472C is not necessarily required.

[0137] A peripheral wall (not shown) lower in height than the peripheral walls 472A and 472B of the second part 472 may be formed on part or all of the first part 471 (the upper edge of the base part 470A). When a peripheral wall lower in height than the peripheral walls 472A and 472B of the second part 472 is provided on the first part 471, the maximum height of the peripheral wall provided on the first part 471 is preferably about 1 / 2 or less (more preferably about 1 / 3 or less, and even more preferably about 1 / 10 or less) of the maximum height of the peripheral walls 472A and 472B. Furthermore, the average height of the peripheral wall that also faces the first part 471 is preferably lower than the average height of the peripheral walls 472A and 472B of the second part 472.

[0138] Thus, by adopting a structure for the insulating member 470 in which the first portion 471 located near the joint 800 does not have an outer peripheral wall (or has a relatively low height), damage to the insulating member 470 due to heat generated during the formation of the joint 800 can be suppressed, thereby increasing the reliability of insulation provided by the insulating member 470.

[0139] As shown in Figures 28 to 30, the current collector 440 includes a through hole 440B, a notch 440C (fitting recess), and a projection 440C. As shown in Figure 28, when viewed from a direction perpendicular to the extending direction (YZ plane direction) of the base portion 470A of the insulating member 470 (X direction), the outer edge of the base portion 470A protrudes more than the current collector 440. Preferably, the outer edge of the base portion 470A of the insulating member 470 protrudes relatively more in the first portion 471 than in the second portion 472.

[0140] The through-hole 440B of the current collector 440 communicates with the through-hole 470B of the insulating member 470. The positive terminal 302 is inserted through the through-hole 440B. The notch 440C of the current collector 440 engages with the projection 472C of the insulating member 470 and can contribute to the alignment of the current collector 440 and the insulating member 470. However, the notch 440C is not necessarily required. The projection 440D of the current collector 440 engages with a recess or hole (not shown) formed in the insulating member 460 (second insulating member) which is positioned between the current collectors 420 and 440 and can contribute to the alignment of the current collector 440 and the insulating member 460.

[0141] As shown in Figures 31 and 32, when comparing the short side of one side (-Z side) of the base portion 470A (Figure 31) with the short side of the other side (+Z side) (Figure 32), it is preferable that the amount of protrusion of the outer peripheral edge of the base portion 470A in the first portion 471 (W1: extension of the base portion 470A) is greater than the amount of protrusion of the outer peripheral edge of the base portion 470A in the second portion 472 where the outer peripheral wall 472B is provided (W2: thickness of the outer peripheral wall 472B). More preferably, W1 / W2 is about 1.2 or more, even more preferably W1 / W2 is about 1.8 or more, and even more preferably W1 / W2 is about 3 or more.

[0142] Furthermore, as shown in Figure 32, the upper end 472A1 (the +Z side end) of the outer peripheral wall 472A is located further from the first portion 471 than the current collector 440 (on the -Z side).

[0143] As described above, by increasing the amount of protrusion of the base portion 470A on the first portion 471 side, even in the first portion 471 where there is no outer peripheral wall (or the height of the outer peripheral wall is relatively low), the creepage distance of the insulating member 470 from the sealing plate 130 to the current collector 440 can be kept large. This suppresses the occurrence of electrical short circuits between the sealing plate 130 and the current collector 440, and further enhances the reliability of insulation provided by the insulating member 470.

[0144] Furthermore, by positioning the upper end 472A1 (the +Z side end) of the outer peripheral wall 472A below the current collector 440 (-Z side), damage to the outer peripheral wall 472A when forming the joint 800 can be suppressed, thereby further enhancing the reliability of insulation provided by the insulating member 470.

[0145] In the secondary battery 1 according to this embodiment, the shape of the current collectors 420 and 440 that constitute the current collection structure on the positive electrode side is not particularly limited. For example, as shown in Figure 33, a joint 800 (welded part) may be formed by irradiating a laser beam 2 (energy ray) onto a protrusion formed on the current collectors 420 and 440, or as shown in Figures 34 and 35, a joint 800 may be formed by irradiating a laser beam 2 onto the boundary portion of the current collectors 420 and 440 that does not have a protrusion. Furthermore, as shown in Figure 36, a joint 800 may be formed by irradiating a laser beam 2 onto the portion where the current collectors 420 and 440, which are formed in a substantially L shape, are overlapped.

[0146] In the secondary battery 1 according to this embodiment, it is preferable that the joint 800 (welded portion) where the current collector 420 (first conductive member) and the current collector 440 (second conductive member) are joined is formed at a position facing the inner surface of the second side portion 112B of the case body 110. By doing so, the joint 800 can be formed by irradiating at least one of the current collectors 420 and 440 with an energy ray from between the case body 110 and the sealing plate 130. As a result, it is possible to provide a more reliable secondary battery 1 with a higher volume density and reduced damage to the insulating members 460 and 470 when forming the joint 800. Furthermore, if the insulating members 460 and 470 are made of resin, it is also possible to effectively suppress carbonization of a part of the insulating members 460 and 470 due to the heat of the laser light 2 (energy ray), which can generate conductive foreign matter.

[0147] While embodiments of the present technology have been described above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present technology is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0148] 1 Secondary battery, 2 Laser beam, 100 Case, 110 Case body, 111 First side section, 112, 112A, 112B Second side section, 113, 114 Opening, 115 Joint, 120, 130 Sealing plate, 134 Liquid injection hole, 150 Gas discharge valve, 200 Electrode body, 201 First electrode body, 202 Second electrode body, 205 First end, 206 Second end, 207 Third end, 208 Fourth end, 210 Negative electrode plate, 211 Negative electrode core, 220 Negative electrode tab group, 220R First recess, 221 Curved section, 222 Tip section, 230 Negative electrode tab, 240 Positive electrode plate, 241 Positive electrode core, 243 Positive electrode protective layer, 250 Positive electrode tab group, 250R 1st recess, 251 curved section, 252 tip section, 260 positive electrode tab, 270 negative electrode tab group, 270R 2nd recess, 271 curved section, 272 tip section, 280 positive electrode tab group, 280R 2nd recess, 281 curved section, 282 tip section, 300 electrode terminal, 301 negative electrode terminal, 301A, 301B area, 302 positive electrode terminal, 303 plate-shaped member, 304 plate-shaped member, 400 current collector, 400A negative electrode current collector, 400B positive electrode current collector, 410 current collector, 411 joint section, 420 current collector, 420A protrusion, 420B notch, 421 joint section, 430, 440 current collector, 440A protrusion, 440B Through hole, 440C, 440D; projection, 460, 470; insulating member, 470A; base part, 470B; through hole, 471; first part, 472; second part, 472A, 472B; outer wall, 472A1; upper end, 472C; projection, 510, 520, 530; insulating member, 600; spacer, 700; insulating sheet, 800; joint.

Claims

1. An electrode body including a first electrode and a second electrode having a different polarity from the first electrode, A case comprising a case body having a first opening, and a first sealing plate that seals the first opening, for housing the electrode body, First conductive member and A second conductive member connected to the first conductive member, A first electrode terminal is electrically connected to the second conductive member and provided on the first sealing plate, The device comprises a base portion disposed between the second conductive member and the first sealing plate, and a first insulating member formed on the outer peripheral edge of the base portion, including an outer peripheral wall that rises in a direction intersecting the extending direction of the base portion. A welded portion is formed where the first conductive member and the second conductive member are welded together. The outer periphery of the base portion includes a first portion located near the welded portion and a second portion other than the first portion. An energy storage device in which the outer peripheral wall is not formed in the first portion, or the maximum height of the outer peripheral wall in the first portion is lower than the maximum height of the outer peripheral wall in the second portion.

2. The first conductive member includes a first plate-like portion, the first plate-like portion having a pair of first main surfaces facing each other and a first side end surface connecting the pair of first main surfaces, The second conductive member includes a second plate-like portion, the second plate-like portion having a pair of second main surfaces facing each other and a second side end surface connecting the pair of second main surfaces, The first conductive member and the second conductive member are arranged such that one of the pair of first main surfaces and one of the pair of second main surfaces are in contact with each other. The energy storage device according to claim 1, wherein the welded portion is formed on the first side end face and the second side end face.

3. The first conductive member includes a first region and a second region, and the second conductive member includes a third region and a fourth region. A second insulating member is placed between the first region and the third region. The energy storage device according to claim 1 or claim 2, wherein the second region and the fourth region are in contact.

4. The outer periphery of the base portion includes a pair of first edges facing each other and a pair of second edges extending in directions intersecting the first edges and facing each other. Each of the pair of first end edges is provided with the outer peripheral wall, The energy storage device according to claim 1 or claim 2, wherein the outer peripheral wall is provided on one of the pair of second end sides, and the first portion is included on the other of the pair of second end sides.

5. When viewed from a direction perpendicular to the extending direction of the base portion, the outer peripheral edge of the base portion protrudes more than the second conductive member. The energy storage device according to claim 1 or claim 2, wherein the amount of protrusion (W1) of the outer peripheral edge of the base portion in the first portion is greater than the amount of protrusion (W2) of the outer peripheral edge of the base portion in the second portion.

6. An electrode body including a first electrode, a second electrode having a different polarity from the first electrode, and a first electrode tab electrically connected to the first electrode, A case comprising a case body having a first opening, and a first sealing plate that seals the first opening, for housing the electrode body, A first conductive member electrically connected to the first electrode tab, A second conductive member connected to the first conductive member, A first electrode terminal is electrically connected to the second conductive member and provided on the first sealing plate, A method for manufacturing an energy storage device comprising a base portion disposed between the second conductive member and the first sealing plate, and a first insulating member formed on the outer peripheral edge of the base portion and including an outer peripheral wall that rises in a direction intersecting the extending direction of the base portion, The step of inserting the electrode body into the case body, The process includes inserting the electrode body into the case body, and then joining a first conductive member electrically connected to the first electrode via a first electrode tab to a second conductive member, The step of joining the first conductive member and the second conductive member includes irradiating at least one of the first conductive member and the second conductive member with an energy ray and welding the first conductive member and the second conductive member to form a welded portion, The outer periphery of the base portion includes a first portion located near the welded portion and a second portion other than the first portion. A method for manufacturing an energy storage device, wherein the first portion does not have the outer peripheral wall formed thereon, or the maximum height of the outer peripheral wall in the first portion is lower than the maximum height of the outer peripheral wall in the second portion.

7. Before joining the first conductive member and the second conductive member, the second conductive member and the first electrode terminal are electrically connected. The method for manufacturing an energy storage device according to claim 6, wherein the step of joining the first conductive member and the second conductive member includes irradiating at least one of the first conductive member and the second conductive member with an energy ray from between the case body and the first sealing plate, thereby welding the first conductive member and the second conductive member.

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