Manufacturing method for energy storage devices

Abstract

To provide a highly reliable method for manufacturing energy storage devices. [Solution] The method for manufacturing an energy storage device comprises the steps of: manufacturing an electrode body, joining a first electrode tab group to a first conductive member and attaching an insulating member to the first conductive member; inserting the electrode body into the case body from the first end side through a second opening after attaching the insulating member to the first conductive member; electrically connecting the first electrode terminals provided on the first sealing plate to the first conductive member after inserting the electrode body into the case body; and sealing the first opening with the first sealing plate after electrically connecting the first electrode terminals to the first conductive member.

Description

Technical Field

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

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, a conductive connection part is formed. It is required to enhance the reliability of the conductive connection part. 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 method for manufacturing a highly reliable power storage device.

Means for Solving the Problems

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

[0007] [1] A method for manufacturing an energy storage device, comprising the steps of: preparing a case body having a first opening and a second opening opposite to the first opening; manufacturing an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode, having a group of first electrode tabs electrically connected to the first electrode at a first end and a group of second electrode tabs electrically connected to the second electrode at a second end opposite to the first end; joining the group of first electrode tabs to a first conductive member and attaching an insulating member to the first conductive member after manufacturing the electrode body; inserting the electrode body into the case body from the first end side through the second opening after attaching the insulating member to the first conductive member; electrically connecting the first electrode terminals provided on a first sealing plate to the first conductive member after inserting the electrode body into the case body; and sealing the first opening with the first sealing plate after electrically connecting the first electrode terminals to the first conductive member.

[0008] [2] The method for manufacturing an energy storage device according to [1], wherein the first electrode tab group includes a first tab group and a second tab group formed separately, the first conductive member includes a first member and a second member provided as separate members, joining the first electrode tab group to the first conductive member includes joining the first member to the first tab group and joining the second member to the second tab group, and attaching the insulating member to the first conductive member includes connecting the first member and the second member to a single insulating member.

[0009] [3] The method for manufacturing an energy storage device according to [2], wherein connecting the first member and the second member to a single insulating member includes connecting the insulating member to one of the first member and the second member, then bending the first tab group and the second tab group, or bending the first tab group and the second tab group, then connecting the insulating member to the other of the first member and the second member.

[0010] [4] The method for manufacturing an energy storage device according to [2], wherein connecting the first member and the second member to a single insulating member is to connect the insulating member to the first member and the second member while bending the first tab group and the second tab group, or after bending the first tab group and the second tab group.

[0011] [5] A method for manufacturing an energy storage device according to any one of [1] to [4], wherein the first conductive member and the first electrode terminal are electrically connected, the first conductive member is joined to the second conductive member attached to the first sealing plate.

[0012] [6] The method for manufacturing an energy storage device according to [5], wherein joining the first conductive member to 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, thereby welding the first conductive member and the second conductive member.

[0013] [7] A method for manufacturing an energy storage device according to any one of [1] to [6], comprising the steps of: electrically connecting a second electrode terminal provided on a second sealing plate to a group of second electrode tabs before inserting the electrode body into the case body; and sealing the second opening with the second sealing plate after inserting the electrode body into the case body.

[0014] [8] A method for manufacturing an energy storage device according to any one of [1] to [7], further comprising the step of covering the electrode body with an insulating electrode body holder before inserting it into the case body.

[0015] [9] The first electrode tab group includes a separately formed first tab group and a second tab group. The first tab group and the second tab group are joined to the first conductive member in a folded state. When viewed from the first direction in which the first opening and the second opening face each other, the joint between the first tab group and the second tab group and the first conductive member is provided within a region extending from the center of the first sealing plate to both ends in the second direction in which the first tab group and the second tab group are arranged, up to a length of 3 / 8 of the total width (B) of the first sealing plate. The manufacturing method of the power storage device according to any one of [1] to [8].

[0016]

[10] The joint between the first electrode tab group and the first conductive member is provided along the extending direction of the first sealing plate. The manufacturing method of the power storage device according to any one of [1] to [9].

Effect of the Invention

[0017] According to this technology, a manufacturing method of a highly reliable power storage device can be provided.

Brief Description of the Drawings

[0018] [Figure 1] It is a front view showing the configuration of a secondary battery according to an embodiment. [Figure 2] It is a view showing the state of the secondary battery shown in FIG. 1 when viewed from the direction of arrow II. [Figure 3] It is a view showing the state of the secondary battery shown in FIG. 1 when viewed from the direction of arrow III. [Figure 4] It is a view showing the state of the secondary battery shown in FIG. 1 when viewed from the direction of arrow IV. [Figure 5] It is a view showing the state of the secondary battery shown in FIG. 1 when viewed 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 a negative electrode plate. [Figure 8] It is a front view showing a negative electrode plate. [Figure 9] It is a cross-sectional view of a positive electrode plate. [Figure 10] It is a front view showing the positive electrode plate. [Figure 11] It is a cross-sectional view taken along the line XI-XI of the secondary battery shown in FIG. 1. [Figure 12] It is a cross-sectional view taken along the line XII-XII 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 a state before two electrode bodies included in a secondary battery according to one embodiment overlap. [Figure 15] It is a cross-sectional view taken along the line XV-XV of the electrode body and the current collector shown in FIG. 14. [Figure 16] It is a perspective view showing a state in which a holder and a spacer are attached to the electrode body. [Figure 17] It is a perspective view showing a state in which a sealing plate is attached to the current collector on the negative electrode side. [Figure 18] It is a cross-sectional view taken along the line XVIII-XVIII of the electrode body and the current collector shown in FIG. 17. [Figure 19] It is a perspective view showing a state in which a sealing plate is attached to the current collector on the positive electrode side. [Figure 20] It is a perspective view showing the configuration of the secondary battery. [Figure 21] It is a front view showing a state in which a first conductive member is connected to an insulating member. [Figure 22] It is a front view showing a state in which one of the two first conductive members is removed from the state shown in FIG. 21. [Figure 23] It is a view showing the state shown in FIG. 22 as seen from the opposite side (back side). [Figure 24] It is a perspective view showing the states of FIGS. 22 and 23. [Figure 25] It is a perspective view showing the first conductive member. [Figure 26] It is a view showing the first conductive member and the insulating member in the XXVI-XXVI cross-section of FIG. 22. [Figure 27] It is a view showing the first conductive member and the insulating member in the XXVII-XXVII cross-section of FIG. 22. [Figure 28] This is a front view showing the insulating material. [Figure 29] This is a front view showing the state in which the second conductive member is attached to the insulating member. [Figure 30] This is a perspective view showing the insulating member with the second conductive member attached. [Figure 31] This diagram shows the current collection structure on the positive electrode side. [Figure 32] This diagram shows the process for forming the joint of a conductive member. [Figure 33] This figure shows the joint formed by the process shown in Figure 32. [Figure 34] This figure shows an example of the location of the joint between the positive electrode tab group and the conductive member. [Figure 35] This is a diagram (part 1) showing an example of the process of bending the positive electrode tab group. [Figure 36] This is a diagram (part 2) showing an example of the process of bending the positive electrode tab group. [Modes for carrying out the invention]

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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).

[0023] 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.

[0024] 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.

[0025] 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.

[0026] "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.

[0027] 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.

[0028] (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.

[0029] 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.

[0030] 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.

[0031] 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-like 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 prismatic secondary battery.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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, etc.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 group of negative electrode tabs (second electrode tab group), and positive electrode tabs (first electrode tabs) provided on each positive electrode plate can be stacked to form a group of positive electrode tabs (first electrode tab group).

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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 (second end) of the first electrode body 201 in the X direction relative to the main body (sealing plate 120 side). The positive electrode tab group 250 is located at the other end (first end) of the first electrode body 201 in the X direction relative to the main body (sealing plate 130 side).

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] (Configuration of electrode body 200) As shown in Figures 7 and 8, 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 negative electrode tab group 220 is electrically connected to the negative electrode. The length of each negative electrode tab 230 in the protruding direction on 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.

[0057] As shown in Figures 9 and 10, a positive electrode tab 260, consisting of a positive electrode core 241, is provided at one end of the positive electrode plate 240 in the width direction. When the positive electrode plates 240 are stacked, multiple positive electrode tabs 260 are stacked to form a positive electrode tab group 250. The positive electrode tab group 250 is electrically connected to the positive electrode. 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 positive electrode tab group 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.

[0058] 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.

[0059] 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.

[0060] (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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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, for example, by laser welding.

[0070] 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.

[0071] 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.

[0072] 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 positioned 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[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, for example, by laser 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 conductive. The plate-shaped member 304 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 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 may be made of resin, for example. More specifically, the material of the insulating sheet 700 may be 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). In this embodiment, the electrode body 200 is inserted into the case body 110 after the insulating members 460 have been attached to the two current collectors 420. In this way, the electrode body 200 can be inserted into the case body 110 with the two current collectors 420 bundled together as one.

[0105] After the electrode body 200 is inserted into the case body 110, 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, starting from an extended state (as 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] The positive electrode tab groups 250 (first tab group) and 280 (second tab group) 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 parts 251 and 281 approach the case body 110 in the Y direction.

[0110] 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).

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] (Connection between insulating member 460 and current collector 420) As shown in Figures 21 to 25, two current collectors 420 (first conductive members) are connected to one insulating member 460. The two current collectors 420 (first member and second member) are joined to positive electrode tab groups 250 and 280 (first tab group and second tab group). However, the scope of this technology is not limited to this, and one current collector 420 may be connected to one insulating member 460.

[0116] It is preferable that the two current collectors 420 have the same shape. It is preferable that the two current collectors 420 are spaced apart from each other. However, the two current collectors 420 may be in contact with each other.

[0117] The current collector 420 is a plate-shaped member having a longitudinal direction in the Z-axis direction and a short direction in the Y-axis direction. The current collector 420 is made of metal, and it is preferable to use, for example, aluminum or an aluminum alloy.

[0118] The current collector 420 includes a through hole 420A (first through hole), a through hole 420B (second through hole), recesses 420C1 and 420C2, a fuse portion 420D, and a plate-shaped portion 420E (first plate-shaped portion).

[0119] The insulating member 460 includes a protrusion 460A (first protrusion), a protrusion 460B (second protrusion), a protrusion 460C (third protrusion), and a plate-like portion 460D (second plate-like portion).

[0120] The plate-shaped portion 420E of the current collector 420 is positioned overlapping with the plate-shaped portion 460D of the insulating member 460. The protrusion 460A of the insulating member 460 is positioned within the through-hole 420A of the current collector 420. This fixes or connects the current collector 420 and the insulating member 460 to each other.

[0121] The through-hole 420A of the current collector 420 is used to connect the current collector 420 to the insulating member 460. Preferably, there is no gap between the shaft portion 460A1 and the inner wall of the through-hole 420A. Alternatively, it is preferable that the gap between the shaft portion 460A1 and the inner wall of the through-hole 420A be as small as possible. If a gap exists between the shaft portion 460A1 and the inner wall of the through-hole 420A, it is preferably about 0.5 mm or less, more preferably about 0.3 mm or less, and even more preferably about 0.2 mm or less.

[0122] When joining current collector 420 and current collector 440, it is preferable to align current collector 420 and current collector 440 relative to each other in the Z direction. This allows for a stable joining of current collector 420 and current collector 440, increasing the reliability of the joint.

[0123] The shape of the through-hole 420A is not limited to a perfect circle; it may be an ellipse, an oblong, or a polygon such as a roughly square or rectangle. Furthermore, the corners of the polygon may be rounded. If the through-hole 420A has a major axis direction or a long side direction, it is preferable that this direction aligns with the direction (Z direction) in which the protrusions 460A and 460B are aligned. It is particularly preferable that the shape of the through-hole 420A is a perfect circle or a shape close to one (for example, a circle with a minor axis / major axis ratio of approximately 0.8 to 1.0).

[0124] The relationship between the protrusion 460B and the through-hole 420B can be set to allow for a larger positional displacement than the relationship between the protrusion 460B and the through-hole 420A, at least in the width direction (Y direction) of the current collector 420. In this case, the play (gap) between the protrusion 460B and the through-hole 420B is larger than the play between the protrusion 460A and the through-hole 420A. The protrusion 460B and the through-hole 420B can function as guides when attaching the current collector 420 to the insulating member 460. Furthermore, the protrusion 460B and the through-hole 420B can suppress large positional displacement of the current collector 420 relative to the insulating member 460. It is preferable that the protrusion height of the protrusion 460B is higher than the protrusion height from the protrusion 460A. This improves the function of the protrusion 460B as a guide.

[0125] The gap between the protrusion 460B and the inner wall of the through-hole 420B (the largest gap) is preferably about 0.3 mm or more, more preferably about 0.5 mm or more, and even more preferably about 1 mm or more. The largest gap between the protrusion 460B and the inner wall of the through-hole 420B is preferably located in the Z direction.

[0126] The shape of the through-hole 420B is not limited to an oval, but may be a perfect circle, an ellipse, or a polygon such as a roughly square or a roughly rectangular shape. Furthermore, the corners of the polygon may be rounded. If the through-hole 420B has a major axis direction or a long side direction, it is preferable that the major axis direction or long side direction aligns with the direction in which the protrusions 460A and 460B are aligned (Z direction).

[0127] However, in the current collector 420, a through hole 420A can be provided instead of the through hole 420B, and in the insulating member 460, a protrusion 460A can be provided instead of the protrusion 460B, with the protrusion 460A being inserted into the through hole 420A. In this case, the current collector 420 and the insulating member 460 can be fixed or connected at two points, upper and lower, thereby achieving more stable mutual retention.

[0128] Recesses 420C1 and 420C2 are notches (constricted portions) provided at the ends of the current collector 420 in the width direction (Y direction). Recesses 420C1 and 420C2 can be provided at approximately the same position in the length direction (Z direction) of the current collector 420. Recesses 420C1 and 420C2 are formed in different shapes from each other. This allows recesses 420C1 and 420C2 to have a function of visual orientation determination (preventing errors in determining the front and back sides).

[0129] The fuse portion 420D is formed to reduce the cross-sectional area of ​​the current collector 420. In addition to the through-hole form exemplified in this embodiment, the fuse portion 420D can also be constructed by a notch, a thin-walled portion, or the like. The fuse portion 420D melts when a current exceeding a predetermined value flows, thereby cutting the conductive path. In the width direction (Y direction) of the current collector 420, it is preferable that the length of the through-hole provided in the fuse portion 420D be greater than the length of the through-hole 420A.

[0130] The insulating member 460 is preferably made of resin. For example, resins such as PP (Polypropylene), PFA (Perfluoroalkoxy alkane), FEP (Fluorinated Ethylene Propylene), PPS (Polyphenylene sulfide), and EPDM (Ethylene Propylene Diene Methylene linkage) can be used.

[0131] As shown in Figure 24, the protrusion 460A of the insulating member 460 has a pair of shaft portions 460A1 (first portion) and a pair of enlarged diameter portions 460A2 (second portion). A slit is provided between the pair of shaft portions 460A1. The pair of shaft portions 460A1 are inserted through the through hole 420A of the current collector 420. The pair of enlarged diameter portions 460A2 are provided at the ends of each of the pair of shaft portions 460A1. The combined outer diameter of the pair of enlarged diameter portions 460A2 (including the slit between the pair of enlarged diameter portions 460A2) is larger than the combined outer diameter of the pair of shaft portions 460A1. When inserting the shaft portions 460A1 into the through hole 420A, the shaft portions 460A1 are deformed so as to tilt radially inward. This allows the enlarged diameter portions 460A2 to pass through the through hole 420A. The tip of the protrusion 460A (enlarged diameter portion 460A2) preferably has a curved shape that can guide insertion into the through hole 420A.

[0132] A through hole 460A3 is formed at the base of the shaft portion 460A1. The through hole 460A3 is formed in a region that encompasses the enlarged diameter portion 460A2 when viewed from the X direction. This makes it possible to easily integrally mold the insulating member 460.

[0133] As shown in Figure 26, in the convex portion 460A, the enlarged diameter portion 460A2, which is the part that protrudes outward (-X side) from the through hole 420A, protrudes outward in the radial direction of the through hole 420A beyond the edge of the through hole 420A. In addition, in the enlarged diameter portion 460A2, the surface on the shaft portion 460A1 side (+X side) faces (preferably in contact with) the outer surface of the current collector 420 in the thickness direction. With this configuration, the current collector 420 and the insulating member 460 are relatively firmly fixed or connected by the convex portion 460A.

[0134] As shown in Figure 27, in the convex portion 460B, the portion that protrudes outward (-X side) from the through hole 420B has an outer diameter smaller than the inner diameter of the through hole 420B. That is, in the convex portion 460B, the portion that protrudes from the through hole 420B does not protrude outward beyond the edge of the through hole 420B in the radial direction of the through hole 420B. Furthermore, a larger gap is formed between the convex portion 460B and the inner wall of the through hole 420B than the gap between the convex portion 460A and the inner wall of the through hole 420A. This effectively suppresses a decrease in the ease of assembling the insulating member 460 to the current collector 420.

[0135] After inserting the shaft portion 460A1 into the through hole 420A and returning the shape of the shaft portion 460A1 to its original state, the enlarged diameter portion 460A2 is positioned outside the through hole 420A and functions as a fixing portion between the current collector 420 and the insulating member 460. At this time, the enlarged diameter portion 460A2 either abuts against the outer surface of the current collector 420 or faces it with a slight gap in the thickness direction of the current collector 420. The width of this gap (in the thickness direction of the current collector 420) is preferably about 0.5 mm or less, more preferably about 0.3 mm or less, and even more preferably about 0.1 mm or less.

[0136] The protrusion 460A is formed on the upper end (one end) side of the current collector 420, and the protrusion 460B is formed on the lower end (the other end) side of the current collector 420. It is preferable that the protrusion 460A is provided closer to the welded joint (the joint 800 described later) between the current collector 420 and the current collector 440 than the protrusion 460B.

[0137] For example, it is preferable that the protrusion 460A is positioned closer to the welded joint (the joint 800 described later) between the current collector 420 and the current collector 440 than to the portion where the positive electrode tab groups 250 and 280 are joined on the current collector 420. Also, for example, the distance in the Z direction from the upper end (the +Z side end) of the joint 800 to the center of the protrusion 460A is preferably about 20 mm or less, more preferably about 15 mm or less, and even more preferably about 10 mm or less.

[0138] By fixing or connecting the current collector 420 and the insulating member 460 near the joint 800, the relative alignment of the current collectors 420 and 440 can be stably performed when joining them, thereby improving the reliability of the joint 800.

[0139] The form of the protrusion 460A is not limited to the examples described above. For example, the protrusion 460A is not limited to being divided into two parts, and the protrusion 460A may consist of a single projection, that is, a single shaft portion and a single enlarged diameter portion. Alternatively, the protrusion 460A may be press-fitted into the through-hole 420A of the current collector 420. Alternatively, the enlarged diameter portion 460A2 may be formed by deforming the protrusion 460A after inserting it into the through-hole 420A, using methods such as heat crimping.

[0140] A portion of the protrusion 460C is positioned within the recess 420C1 of one current collector 420, and another portion is positioned within the recess 420C2 of the other current collector 420. The protrusion height of the protrusion 460C is preferably lower than the protrusion heights of the protrusions 460A and 460B. Furthermore, the protrusion height of the protrusion 460C is preferably smaller than the thickness of the current collector 420.

[0141] In the secondary battery 1 according to this embodiment, by connecting the current collector 420 joined to the positive electrode tab groups 250 and 280 to the insulating member 460, when inserting the electrode body 200 into the case body 110 with the positive electrode tab groups 250 and 280 side first, it is possible to suppress unintended deformation of the positive electrode tab groups 250 and 280. Therefore, damage to the positive electrode tab groups 250 and 280 can be suppressed. Thus, a highly reliable secondary battery 1 is obtained.

[0142] Furthermore, since the positional relationship between the current collector 420 and the current collector 440 can be stabilized via the insulating member 460, the reliability of the connection between the current collector 420 and the current collector 440, which is made after inserting the electrode body 200 into the case body 110, can be improved. As a result, a more reliable secondary battery 1 can be obtained.

[0143] (Placement of the current collector 440 on the insulating member 470) As shown in Figures 28 to 30, the insulating member 470 and the current collector 440 (second conductive member) have a longitudinal direction in the Z-axis direction and a short direction in the Y-axis direction.

[0144] The insulating member 470 includes a base portion 470A and a through hole 470B. The base portion 470A is formed in a plate shape and is positioned 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.

[0145] The current collector 440 is a plate-shaped member having a through hole 440A and a projection 440B. The current collector 440 is made of metal, preferably aluminum or an aluminum alloy. The current collector 440 is placed on the insulating member 470. The through hole 440A 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 440A. The projection 440B of the current collector 440 engages with a recess or hole (not shown) formed in the insulating member 460, and can contribute to the alignment of the current collector 440 and the insulating member 460.

[0146] (Positive electrode current collection structure) As shown in Figure 31, the insulating member 460 connected to the current collector 420 and the current collector 440 attached to the sealing plate 130 together with the insulating member 470 are superimposed. At this time, the current collector 420 and the current collector 440 are in contact with each other at their upper ends. The insulating member 470 is placed between the sealing plate 130 and the current collector 440.

[0147] A stepped portion is formed on at least one of the current collectors 420 and 440 (current collector 420 in the example of Figure 31). This creates a tapered gap S1 between the current collectors 420 and 440. The gap S1 gradually decreases towards the upper side of the current collectors 420 and 440. 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 lower side of the current collectors 420 and 440, 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.

[0148] As shown in Figures 32 and 33, by irradiating the upper end (first end) of the current collector 420 and the upper end (second end) of the current collector 440 with energy rays 2, a joint 800 (welded portion) is formed to join the current collectors 420 and 440. This electrically connects the current collector 420 and the positive terminal 302. Preferably, the current collectors 420 and 440 are joined by welding. More preferably, the current collectors 420 and 440 are joined by, for example, laser welding. It is preferable that the energy rays 2 are irradiated from between the case body 110 and the sealing plate 130.

[0149] In this embodiment, 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 of the current collectors 420 and 440, as shown in Figure 33. 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 33.

[0150] When the sealing plate 130 is assembled to the case body 110, the joint portion 800 is pushed into the case body 110. After the sealing plate 130 is assembled to the case body 110, the joint portion 800 faces the inner surface (second side portion 112B) of the case body 110.

[0151] In the secondary battery 1 according to this embodiment, the current collectors 420 and 440 are irradiated with energy rays 2 outside the case body 110 to form a joint portion 800, and then the joint portion 800 is pushed into the inside of the case body 110. In this way, a secondary battery 1 with high energy density can be obtained while suppressing the generation of foreign matter and damage to insulating materials.

[0152] As shown in Figure 31, in the positive electrode current collection structure, the current collector 420 protrudes below the insulating member 460 (on the opposite side of the joint 800). Also, the insulating member 460 protrudes below the current collector 440 (on the opposite side of the joint 800).

[0153] Since the current collector 420 protrudes below the insulating member 460, during the joining process of the current collectors 420 and 440, a positioning jig is provided at the upper end of the current collectors 420 and 440, and the current collector 420 is pushed up from below, making it easy to align the current collectors 420 and 440 in the height direction (Z direction). This makes it possible to improve the reliability of the joint 800 of the current collectors 420 and 440.

[0154] Furthermore, since the insulating member 460 protrudes below the current collector 440, stable insulation between the current collectors 420 and 440 can be ensured.

[0155] (Location of joint 421) As shown in Figure 34, when the positive electrode tab group 250 (first tab group) and the positive electrode tab group 280 (second tab group) are viewed from the X direction (first direction), the positive electrode tab groups 250 and 280 are aligned in the Y direction (second direction). In the example in Figure 34, the joint 421 between the positive electrode tab groups 250 and 280 and the current collector 420 is arranged symmetrically with respect to an axis extending in the Z direction (third direction) at the center of the sealing plate 130 in the Y direction (B2=B3).

[0156] The connection point 421 between the positive electrode tab groups 250, 280 and the current collector 420 is preferably located within a region extending from the center of the sealing plate 130 in the Y direction toward both ends, up to a length of approximately 3 / 8 of the total width (B) of the sealing plate 130 (B1 ≤ approximately 3 / 4B, B2 ≥ approximately B / 8, B3 ≥ approximately B / 8). Here, "located within a region" means that the entire connection point 421 is located within the above-mentioned "region".

[0157] In the secondary battery 1 according to this embodiment, by bending the positive electrode tab groups 250 and 280 into a roughly S-shape, the connection point 421 between the positive electrode tab groups 250 and 280 and the current collector 420 can be aligned with the extending direction of the sealing plate 130, thereby improving the storage efficiency of the positive electrode tab groups 250 and 280 and improving the energy density of the secondary battery 1.

[0158] Here, as shown in the example in Figure 34, by moving the connection point 421 between the positive electrode tab groups 250 and 280 and the current collector 420 closer to the center in the Y direction, the positive electrode tab groups 250 and 280 can be easily bent into a roughly S-shape. This further improves the storage efficiency of the positive electrode tab groups 250 and 280, and increases the energy density of the secondary battery 1.

[0159] (Bending process for positive electrode tab groups 250 and 280) As shown in Figures 35 and 36, the positive electrode tab groups 250 and 280 are bent into a roughly S-shape. By bending the positive electrode tab groups 250 and 280 before pushing the sealing plate 130 into the case body 110, it is possible to more reliably suppress unintended contact and friction with other components caused by the positive electrode tab groups 250 and 280 deforming into an unintended shape. As a result, damage to the positive electrode tab groups 250 and 280 is suppressed, and the energy density can be improved while increasing the reliability of the secondary battery 1.

[0160] In the example shown in Figure 35, after connecting the insulating member 460 to the current collector 420 on the positive electrode tab group 280 side of the two current collectors 420 (first member and second member) (Figure 35(A)), the insulating member 460 is also connected to the current collector 420 on the positive electrode tab group 250 side while bending the positive electrode tab groups 250 and 280 into a roughly S-shape (shaping process) (Figure 35(B)).

[0161] In the example shown in Figure 35, the positive electrode tab groups 250 and 280 are bent simultaneously using jigs 3 and 4, but the bending of the positive electrode tab groups 250 and 280 may be performed separately. Alternatively, the insulating member 460 may be connected to the current collector 420 after the positive electrode tab groups 250 and 280 have been bent.

[0162] In the example shown in Figure 35, the alignment of the through-hole 420A of the current collector 420 with the protrusion 460A of the insulating member 460 can be performed for each individual current collector 420, thus improving the workability of assembly.

[0163] In the example shown in Figure 36, the positive electrode tab groups 250 and 280 are bent into a roughly S-shape (shaping process), and then the insulating member 460 is connected to the two current collectors 420 (first member and second member).

[0164] In the example shown in Figure 36, the bending of the positive electrode tab groups 250 and 280 may be done simultaneously or separately. Alternatively, the insulating member 460 may be connected to the current collector 420 while the positive electrode tab groups 250 and 280 are being bent.

[0165] In the examples shown in Figures 35 and 36, by providing jig 3 on the outside of the positive electrode tab groups 250 and 280, and jig 4 between the positive electrode tab groups 250 and 280, it becomes easier to perform a roughly S-shaped bend. Therefore, it is preferable to provide both jig 3 and 4. However, it is possible to omit either jig 3 or 4.

[0166] 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]

[0167] 1 Secondary battery, 2 Energy rays, 3,4 Fixture, 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 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, 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, 251 Curved section, 252 Tip section, 260 Positive electrode tab, 270 Negative electrode tab group, 271 Curved section, 272 Tip section, 280 Positive electrode tab group, 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 area, 420 Current collector, 420A, 420B Through hole, 420C1, 420C2 Recess, 420D Fuse section, 420E Plate-shaped section, 421 Joint area, 430, 440 Current collector, 440A Through hole, 440B Projection, 460 insulating member, 460A convex part, 460A1 shaft part, 460A2 enlarged diameter part, 460A3 through hole, 460B, 460C convex part, 460D plate-shaped part, 470 insulating member, 470A base part, 470B through hole, 510, 520, 530 insulating member, 600 spacer, 700 insulating sheet, 800 joint part.

Claims

1. A step of preparing a case body having a first opening and a second opening facing the first opening, A step of manufacturing an electrode body comprising a first electrode and a second electrode having a polarity different from that of the first electrode, having a group of first electrode tabs electrically connected to the first electrode at a first end, and a group of second electrode tabs electrically connected to the second electrode at a second end opposite to the first end, After fabricating the electrode body, the first electrode tab group is joined to the first conductive member, and an insulating member is attached to the first conductive member. After attaching the insulating member to the first conductive member, the electrode body is inserted into the case body from the first end side through the second opening, After inserting the electrode body into the case body, the first electrode terminal provided on the first sealing plate is electrically connected to the first conductive member. A method for manufacturing an energy storage device, comprising the steps of electrically connecting the first electrode terminal and the first conductive member, and then sealing the first opening with the first sealing plate.

2. The first electrode tab group includes a first tab group and a second tab group formed separately. The first conductive member includes a first member and a second member provided as separate members. Joining the first electrode tab group to the first conductive member includes joining the first tab group to the first member and joining the second tab group to the second member. The method for manufacturing an energy storage device according to claim 1, wherein attaching the insulating member to the first conductive member includes connecting the first member and the second member to a single insulating member.

3. Connecting the first member and the second member to a single insulating member is, A method for manufacturing an energy storage device according to claim 2, comprising connecting the insulating member to one of the first member and the second member, and then, while bending the first tab group and the second tab group, or after bending the first tab group and the second tab group, connecting the insulating member to the other of the first member and the second member.

4. Connecting the first member and the second member to a single insulating member is, A method for manufacturing an energy storage device according to claim 2, comprising connecting the insulating member to the first member and the second member while bending the first tab group and the second tab group, or after bending the first tab group and the second tab group.

5. A method for manufacturing an energy storage device according to any one of claims 1 to 4, wherein electrically connecting the first conductive member and the first electrode terminal includes joining the first conductive member to a second conductive member attached to the first sealing plate.

6. The method for manufacturing an energy storage device according to claim 5, wherein joining the first conductive member to 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.

7. Before inserting the electrode body into the case body, the process involves electrically connecting the second electrode terminal provided on the second sealing plate with the second electrode tab group, A method for manufacturing an energy storage device according to any one of claims 1 to 4, comprising the steps of inserting the electrode body into the case body and then sealing the second opening with the second sealing plate.

8. A method for manufacturing an energy storage device according to any one of claims 1 to 4, further comprising the step of covering the electrode body with an insulating electrode body holder before inserting it into the case body.

9. The first electrode tab group includes a first tab group and a second tab group formed separately. The first tab group and the second tab group are joined to the first conductive member in a bent state. A method for manufacturing an energy storage device according to any one of claims 1 to 4, wherein, when viewed from a first direction in which the first opening and the second opening face each other, the joint between the first tab group and the second tab group and the first conductive member is provided within a region extending from the center of the first sealing plate toward both ends in a second direction in which the first tab group and the second tab group are aligned, up to a length of 3 / 8 of the total width (B) of the first sealing plate.

10. The method for manufacturing an energy storage device according to any one of claims 1 to 4, wherein the joint between the first electrode tab group and the first conductive member is provided along the extending direction of the first sealing plate.

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