Energy storage device and method for manufacturing the same
By employing conductive members with protrusions joined using energy rays, the reliability of joints in power storage devices is enhanced, addressing the limitations of existing technologies.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- PRIME PLANET ENERGY & SOLUTIONS INC
- Filing Date
- 2024-11-27
- Publication Date
- 2026-06-08
Smart Images
Figure 2026092880000001_ABST
Abstract
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 respectively attached to cap plates (, 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, joints are formed between conductive members. It is required to improve the reliability of the joints. 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] 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 for sealing the first opening; a first conductive member electrically connected to the first electrode tab; a second conductive member connected to the first conductive member; and a first electrode terminal electrically connected to the second conductive member and provided on the first sealing plate, comprising the steps of inserting the electrode body into the case body and joining the first conductive member electrically connected to the first electrode via the first electrode tab and the second conductive member after inserting the electrode body into the case body, wherein at least one of the first conductive member and the second conductive member has a protrusion before joining the first conductive member and the second conductive member, and the step of joining the first conductive member and the second conductive member includes irradiating the protrusion with an energy ray and joining the first conductive member and the second conductive member.
[0008] [2] The method for manufacturing an energy storage device according to [1], 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 the protrusion with an energy ray from between the case body and the first sealing plate to join the first conductive member and the second conductive member.
[0009] [3] The method for manufacturing an energy storage device according to [1] or [2], 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 protrusion is formed on at least one of the first side end surface and the second side end surface at least before joining the first conductive member and the second conductive member.
[0010] [4] The method for manufacturing an energy storage device according to any one of [1] to [3], wherein the protrusions include a first protrusion formed on the first conductive member and a second protrusion formed on the second conductive member.
[0011] [5] A method for manufacturing an energy storage device according to any one of [1] to [4], 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, an insulating member is disposed between the first region and the third region, and the second region and the fourth region are in contact.
[0012] [6] An electrode body including a first electrode and a second electrode having a different polarity from the first electrode; a case body having a first opening and a first sealing plate that seals the first opening, comprising a case for housing the electrode body; a first conductive member; a second conductive member connected to the first conductive member; and a first electrode terminal electrically connected to the second conductive member and provided on the first sealing plate, 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 connecting the pair of first main surfaces A power storage device having a surface, the second conductive member including 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 being arranged such that one of the pair of first main surfaces and one of the pair of second main surfaces abut each other, a convex portion formed on at least one of the first side end surface and the second side end surface, and a welded portion being formed in the region including the convex portion to join the first conductive member and the second conductive member.
[0013] [7] The energy storage device according to [6], wherein the protrusions include a first protrusion formed on the first conductive member and a second protrusion formed on the second conductive member.
[0014] [8] The energy storage device according to [6] or [7], 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, an insulating member is disposed between the first region and the third region, and the second region and the fourth region are in contact. [Effects of the Invention]
[0015] This technology makes it possible to provide a highly reliable energy storage device and a method for manufacturing the same. [Brief explanation of the drawing]
[0016] [Figure 1] This is a front view showing the configuration of a secondary battery according to an embodiment. [Figure 2] This figure shows the secondary battery shown in Figure 1 as viewed 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 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 the state before two electrode bodies included in the 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 perspective view showing the current collecting structure on the positive electrode side before joining conductive members to each other. [Figure 22]This is a cross-sectional view of section XXII-XXII in Figure 21. [Figure 23] This is a diagram (part 1) showing an example of the formation location of the protrusion. [Figure 24] This is a diagram (part 2) showing an example of the formation location of the protrusion. [Figure 25] This is Figure (3) showing an example of the formation location of the protrusion. [Figure 26] This is a diagram (part 1) showing an example of the cross-sectional shape of the convex part. [Figure 27] This is a diagram (part 2) showing an example of the cross-sectional shape of the convex part. [Figure 28] This is Figure (3) showing an example of the cross-sectional shape of the convex part. [Figure 29] This is Figure (No. 4) showing an example of the cross-sectional shape of the convex part. [Figure 30] This is Figure (No. 5) showing an example of the cross-sectional shape of the convex part. [Figure 31] This is a cross-sectional view showing an example of the irradiation location of an energy ray. [Figure 32] This is a cross-sectional view showing the junction after irradiation with energy rays. [Figure 33] This is a diagram (part 1) showing an example of a joint formation region. [Figure 34] This is a diagram (part 2) showing an example of a joint formation region. [Figure 35] This is Figure (3) showing an example of a joint formation region. [Figure 36] This is Figure (4) showing an example of a joint formation region. [Figure 37] This is a cross-sectional view showing a modified example of the current collection structure on the positive electrode side. [Modes for carrying out the invention]
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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).
[0021] 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.
[0022] 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.
[0023] 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.
[0024] "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.
[0025] 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.
[0026] (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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] 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.
[0046] 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.
[0047] 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.
[0048] 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.
[0049] 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.
[0050] 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.
[0051] 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.
[0052] 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.
[0053] 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.
[0054] 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.
[0055] (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.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] (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.
[0060] 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.
[0061] 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.
[0062] 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.
[0063] 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.
[0064] 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.
[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 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.
[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 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.
[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. The protrusions on the spacer 600 are positioned within the first recess 220R and the second recess 270R.
[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 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.
[0080] 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.
[0081] 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.
[0082] 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.
[0083] 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.
[0084] 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.
[0085] 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.
[0086] 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.
[0087] 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.
[0088] 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.
[0089] 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.
[0090] 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.
[0091] 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.
[0092] 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).
[0093] 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).
[0094] (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.
[0095] 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.
[0096] 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.
[0097] 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.
[0098] 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.
[0099] 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.
[0100] "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.
[0101] 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.
[0102] 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.
[0103] 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.
[0104] 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.
[0105] 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.
[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 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.
[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] (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.
[0116] 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.
[0117] 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.
[0118] 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.
[0119] 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.
[0120] 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.
[0121] 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.
[0122] 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.
[0123] 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.
[0124] 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.
[0125] In the positive electrode current collection structure of the secondary battery 1 according to this embodiment, bonding is performed by irradiating the protrusions 420A and 440A provided at the upper ends of the current collectors 420 and 440 with energy rays. This concentrates the heat generated by the irradiation of energy rays around the protrusions 420A and 440A, making it possible to perform highly reliable bonding efficiently (with less energy).
[0126] Figures 23 to 25 show the protrusions 420A and 440A as viewed from the +Z direction. As in the example in Figure 23, the protrusions 420A and 440A may be formed over the entire width (Y direction) of the current collectors 420 and 440, respectively, or as in the example in Figure 24, the protrusions 420A and 440A may be formed only on a part of the width (Y direction) of the current collectors 420 and 440 (only the part where joining is necessary). As shown in Figure 25, the current collector 420 may be made of a single piece. In the example in Figure 25, the protrusions 420A are formed over the entire width (Y direction) of the current collector 420 made of a single piece. As a further variation from Figure 25, the protrusions 420A may be formed on only a part of the current collector 420 made of a single piece.
[0127] As shown in Figures 26 to 30, the cross-sectional shapes of the protrusions 420A and 440A can also be modified in various ways. For example, as in Figure 26, protrusions 420A and 440A may be provided that are substantially the same shape as each other; as in Figure 27, the protrusion heights (in the Z direction) of the protrusions 420A and 440A may be different (H2 > H1); and as in Figure 28, the thicknesses (in the X direction) of the protrusions 420A and 440A may be different (T1 > T2).
[0128] The protruding height (H) of the protrusions 420A and 440A is preferably about 0.5 mm or more (more preferably about 2 mm or more), and preferably about 5 mm or less (more preferably about 4 mm or less). The protruding height (H) of the protrusions 420A and 440A is preferably about 20% or more (more preferably about 100% or more), and preferably about 150% or less (more preferably about 120% or less), of the thickness of the current collectors 420 and 440, respectively.
[0129] The thickness (T) of the protrusions 420A and 440A is preferably about 0.5 mm or more (more preferably about 1 mm or more), and preferably about 2 mm or less (more preferably about 1.5 mm or less). The thickness (T) of the protrusions 420A and 440A is preferably about 20% or more (more preferably about 30% or more), and preferably about 50% or less (more preferably about 40% or less), of the thickness of the current collectors 420 and 440, respectively.
[0130] The thicknesses of the current collectors 420 and 440 may be approximately the same or different. The thicknesses of the current collectors 420 and 440 are preferably about 2 mm or more (more preferably about 2.5 mm or more), and preferably about 4 mm or less (more preferably about 3 mm or less).
[0131] As shown in the example in Figure 21, when the volume of the current collector 440 is larger than the volume of the current collector 420, it is preferable to make the protruding height (H2) of the protrusion 440A of the current collector 440 greater than the protruding height (H1) of the protrusion 420A of the current collector 420, as shown in Figure 27. Alternatively, as shown in Figure 28, it is preferable to make the width (T2) of the protrusion 440A of the current collector 440 smaller than the width (T1) of the protrusion 420A of the current collector 420. This allows the heat generated during welding to be concentrated on the protrusion 440A even if the current collector 440 has a large heat capacity, and a joint 800 (welded part) can be stably formed between the current collector 440 and the current collector 420. It is preferable that the current collector 440 and the current collector 420 are made of the same type of metal (for example, selected from aluminum and aluminum alloy, or selected from copper and copper alloy, respectively).
[0132] Furthermore, instead of the roughly rectangular protrusions 420A and 440A shown in Figures 26 to 28, notches 420B and 440B may be provided in the protrusions 420A and 440A, respectively, so that the boundary between the protrusions 420A and 440A has a groove shape, as shown in Figure 29. According to the example in Figure 29, when laser light as an energy beam is irradiated, sputter is reflected within the groove, thus suppressing the scattering of sputter.
[0133] Furthermore, as shown in the example in Figure 30, the tapered cross-sectional shape of the protrusions 420A and 440A, where the thickness increases towards the base of the protrusions 420A and 440A, allows for an increased welding allowance when joining the current collectors 420 and 440 by welding, for example.
[0134] As shown in Figure 31, it is preferable that the laser beam 2 (energy beam) is irradiated onto the boundary between the protrusions 420A and 440A. However, the laser beam 2 may also be irradiated at a position slightly shifted from the state shown in Figure 31, either towards the protrusion 420A side or the protrusion 440A side.
[0135] As shown in Figure 32, a joint 800 (welded portion) is formed to join the current collectors 420 and 440. 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 32. However, the center of the joint 800 may be slightly shifted from the state shown in Figure 32 towards either the current collector 420 side or the current collector 440 side.
[0136] In the examples shown in Figures 31 and 32, after irradiation with laser light 2, the protrusions 420A and 440A are almost completely eliminated, and the weld bead constituting the joint 800 protrudes slightly from the upper end surfaces of the current collectors 420 and 440. The protrusion height of the joint 800 (Figure 32) is preferably about 1 / 10 or less (more preferably about 1 / 20 or less) of the protrusion height of the protrusions 420A and 440A (Figure 31).
[0137] As shown in Figures 33 to 36, various modifications are possible to the area where the joint portion 800 is formed. As in the example in Figure 33, one continuous joint portion 800 may be formed on one protrusion 420A, or as in the example in Figure 34, multiple (two in Figure 34) divided joint portions 800 may be formed on one protrusion 420A. As shown in Figure 35, the joint portion 800 may be formed over the entire protrusions 420A and 440A. By doing so as in Figure 35, the entire area of the formed protrusions 420A and 440A can be utilized as the joint portion 800, which is advantageous from the viewpoint of maximizing the joining area. In addition, in the example in Figure 35, since the entire area of the protrusions 420A and 440A is melted, it is easy to determine whether the product is good after the joint portion 800 has been formed. As shown in Figure 33, in the width direction (left-right direction in Figure 33) of the current collector 440, the protrusion 440A is formed over the entire end of the current collector 440, and it is preferable that the joint portion 800 is formed at a position away from the end of the protrusion 440A. This allows for the stable formation of the protrusion 440A on the current collector 440 and the stable formation of the joint portion 800, resulting in a more reliable secondary battery 1 (energy storage device). Furthermore, in the width direction (left-right direction in Figure 33) of the current collector 420, it is more preferable that the protrusion 420A is formed over the entire end of the current collector 420, and that the joint portion 800 is formed at a position away from the end of the protrusion 420A.
[0138] In the example shown in Figure 36, a joint portion 800 is formed on the portion of the convex portion 420A in the width direction (Y direction) of the current collector 420, excluding both ends. As a further modification from Figure 36, the joint portion 800 may be formed over the entire width direction (Y direction) of the convex portions 420A and 440A.
[0139] In this embodiment, the current collection structure on the positive electrode side is not limited to the one described above. For example, as shown in the modified example in Figure 37, a structure in which a bent portion (stepped portion) is provided on the current collector 440 side may be used. In such a configuration, the joint portion 800 between the current collector 420 and the current collector 440 can be positioned away from the insulating member 470, thereby more effectively suppressing damage to the insulating member 470.
[0140] In the secondary battery 1 according to this embodiment, it is particularly preferable to form a joint 800 (welded portion) by irradiating at least one of the current collector 420 (first conductive member) and the current collector 440 (second conductive member) with laser light 2 (energy ray) from between the case body 110 and the sealing plate 130. This allows, for example, the length of the positive electrode tab 260 to be shortened and the space occupied by the positive electrode tab groups 250 and 280 to be reduced, thereby providing a secondary battery 1 (energy storage device) with a higher volume density. Furthermore, by providing protrusions 420A and 440A on at least one of the current collectors 420 and 440, and forming the joint 800 at the protrusions 420A and 440A, a highly reliable joint 800 can be formed while suppressing the energy of the laser light 2. Therefore, the amount of spatter generated during welding can be reduced. As a result, the presence of spatter inside the case 100 can be effectively suppressed, resulting in a more reliable secondary battery 1.
[0141] 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]
[0142] 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 Notch section, 460, 470, 510, 520, 530 Insulating material, 600 Spacer, 700 Insulating sheet, 800 Joint section.
Claims
1. 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 method for manufacturing an energy storage device comprising a first electrode terminal electrically connected to the second conductive member and provided on the first sealing plate, 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, At least before joining the first conductive member and the second conductive member, at least one of the first conductive member and the second conductive member has a protrusion, A method for manufacturing an energy storage device, comprising the step of joining the first conductive member and the second conductive member, which includes irradiating the protrusion with an energy ray to join the first conductive member and the second conductive member.
2. 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 1, wherein the step of joining the first conductive member and the second conductive member includes irradiating the protrusion with an energy ray from between the case body and the first sealing plate to join the first conductive member and the second conductive member.
3. 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. A method for manufacturing an energy storage device according to claim 1 or claim 2, wherein the protrusion is formed on at least one of the first side end face and the second side end face at least before joining the first conductive member and the second conductive member.
4. The method for manufacturing an energy storage device according to claim 1 or claim 2, wherein the protrusion includes a first protrusion formed on the first conductive member and a second protrusion formed on the second conductive member.
5. 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. An insulating member is placed between the first region and the third region. A method for manufacturing an energy storage device according to claim 1 or claim 2, wherein the second region and the fourth region are in contact.
6. 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, The second conductive member is electrically connected to a first electrode terminal provided on the first sealing plate, 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. A power storage device in which a protrusion is formed on at least one of the first side end face and the second side end face, and a welded portion is formed in the region including the protrusion to join the first conductive member and the second conductive member.
7. The energy storage device according to claim 6, wherein the protrusion includes a first protrusion formed on the first conductive member and a second protrusion formed on the second conductive member.
8. 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. An insulating member is placed between the first region and the third region. The energy storage device according to claim 6 or claim 7, wherein the second region and the fourth region are in contact.