Manufacturing method of secondary batteries

Abstract

To improve the energy density of secondary batteries and to manufacture them stably. [Solution] The first electrode body 201 has a first electrode tab 220 and a second electrode tab 250. The second electrode body 202 has a third electrode tab 270 and a fourth electrode tab 280. The first electrode tab 220 is joined to the first current collector 410. The second electrode tab 250 is joined to the second current collector 420. The third electrode tab 270 is joined to the third current collector 430. The fourth electrode tab 280 is joined to the fourth current collector 440. The first current collector 410 and the third current collector 430 are made of separate parts. The second current collector 420 and the fourth current collector 440 are made of separate parts.

Description

Technical Field

[0001] This technology relates to a method for manufacturing a secondary battery.

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, 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 the secondary battery described in Patent Document 1, there is room to improve the energy density and stably manufacture the secondary battery.

[0005] This technology has been made to solve the above problems, and an object thereof is to provide a method for manufacturing a secondary battery that can improve the energy density and be stably manufactured.

Means for Solving the Problems

[0006] A secondary battery based on this technology comprises a first electrode body, a second electrode body, and a case. The first electrode body and the second electrode body each include a first electrode and a second electrode having a different polarity from the first electrode. The case houses the first electrode body and the second electrode body. The case includes a cylindrical case body, a first sealing plate, and a second sealing plate. The case body has a first opening located at the end on the first side and a second opening located at the end on the second side opposite to the end on the first side. The first sealing plate seals the first opening. The second sealing plate seals the second opening. The first sealing plate is provided with a first electrode terminal electrically connected to the first electrode. The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode. The first electrode body has a first electrode tab electrically connected to the first electrode at the end on the first sealing plate side and a second electrode tab electrically connected to the second electrode at the end on the second sealing plate side. The second electrode body has a third electrode tab electrically connected to the first electrode at the end facing the first sealing plate, and a fourth electrode tab electrically connected to the second electrode at the end facing the second sealing plate. The first electrode tab is joined to the first current collector. The second electrode tab is joined to the second current collector. The third electrode tab is joined to the third current collector. The fourth electrode tab is joined to the fourth current collector. The first and third current collectors are made up of separate parts. The second and fourth current collectors are made up of separate parts. Each of the first and third current collectors is connected to a fifth current collector electrically connected to the first electrode terminal. Each of the second and fourth current collectors is connected to a sixth current collector electrically connected to the second electrode terminal.

[0007] The secondary battery in the method for manufacturing a secondary battery based on this technology comprises a first electrode body, a second electrode body, and a case. The first electrode body and the second electrode body each include a first electrode and a second electrode having a different polarity from the first electrode. The case houses the first electrode body and the second electrode body. The case includes a cylindrical case body, a first sealing plate, and a second sealing plate. The case body has a first opening located at the end on the first side and a second opening located at the end on the second side opposite to the first end. The first sealing plate seals the first opening. The second sealing plate seals the second opening. The first sealing plate is provided with a first electrode terminal electrically connected to the first electrode. The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode. The first electrode body has a first electrode tab electrically connected to the first electrode at the end on the first sealing plate side and a second electrode tab electrically connected to the second electrode at the end on the second sealing plate side. The second electrode body has a third electrode tab electrically connected to the first electrode at the end facing the first sealing plate, and a fourth electrode tab electrically connected to the second electrode at the end facing the second sealing plate. The first electrode tab is joined to the first current collector. The second electrode tab is joined to the second current collector. The third electrode tab is joined to the third current collector. The fourth electrode tab is joined to the fourth current collector. The first and third current collectors are made up of separate parts. The second and fourth current collectors are made up of separate parts. Each of the first and third current collectors is connected to a fifth current collector electrically connected to the first electrode terminal. Each of the second and fourth current collectors is connected to a sixth current collector electrically connected to the second electrode terminal.A method for manufacturing a secondary battery includes the steps of manufacturing a first electrode body and a second electrode body, joining a first electrode tab to a first current collector after manufacturing the first electrode body and the second electrode body, joining a second electrode tab to a second current collector after manufacturing the first electrode body and the second electrode body, joining a third electrode tab to a third current collector after manufacturing the first electrode body and the second electrode body, joining a fourth electrode tab to a fourth current collector after manufacturing the first electrode body and the second electrode body, and in the thickness direction of the first electrode body and the second electrode body, The process includes the steps of: overlapping the electrode body and the second electrode body; connecting the first current collector and the third current collector to the fifth current collector after the first electrode body and the second electrode body have been overlapped; inserting the first electrode body and the second electrode body into the case body from the first opening, with the second electrode tab and the fourth electrode tab side leading, after the first current collector and the third current collector have been connected to the fifth current collector; and connecting the second current collector and the fourth current collector, which protrude from the second opening, to the sixth current collector after the first electrode body and the second electrode body have been inserted into the case body. "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. Furthermore, the first electrode and the second electrode may or may not be fixed with tape or the like. [Effects of the Invention]

[0008] This technology improves the energy density of secondary batteries and enables the stable manufacture of secondary batteries. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view showing the configuration of a secondary battery according to Embodiment 1 of this technology. [Figure 2] This figure shows the secondary battery shown in Figure 1 as viewed from the direction of arrow II. [Figure 3] This figure shows the secondary battery shown in Figure 1 as viewed 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 front view showing the negative electrode raw plate before the negative electrode plate is formed. [Figure 8] It is a cross-sectional view taken along line VIII-VIII of the negative electrode raw plate shown in FIG. 7. [Figure 9] It is a front view showing the negative electrode plate formed from the negative electrode raw plate. [Figure 10] It is a front view showing the positive electrode raw plate before the positive electrode plate is formed. [Figure 11] It is a cross-sectional view taken along line XI-XI of the positive electrode raw plate shown in FIG. 10. [Figure 12] It is a front view showing the positive electrode plate formed from the positive electrode raw plate. [Figure 13] It is a cross-sectional view taken along line XIII-XIII of the secondary battery shown in FIG. 1. <00…It is a cross-sectional view taken along line XIV-XIV of the secondary battery shown in FIG… [Figure 15] It is a flowchart showing the manufacturing method of the secondary battery according to Embodiment 1. [Figure 16] It is a perspective view showing the state before the two electrode bodies included in the secondary battery according to Embodiment 1 overlap. [Figure 17] It is a cross-sectional view showing the state of bending the electrode tab. [Figure 18] It is a perspective view showing the state where a holder and a spacer are attached to the electrode body. [Figure 19] It is a perspective view showing the state where the first sealing plate is attached to the first current collector. [Figure 20] It is a cross-sectional view taken along line XX-XX of the electrode body and the current collector shown in FIG. 19. [Figure 21] It is a perspective view showing the state where the electrode body is inserted into the case body. [Figure 22] It is a perspective view showing the state where the second sealing plate is attached to the second current collector. [Figure 23] It is a sectional view taken along line XXIII-XXIII of the electrode body and the current collector shown in FIG. 22. [Figure 24] It is a view showing the state of the current collector shown in FIG. 22 as seen from the direction of arrow XXIV. [Figure 25] It is a sectional view taken along line XXV-XXV of the current collector shown in FIG. 24. [Figure 26] It is a perspective view showing the configuration of the secondary battery according to Embodiment 1. [Figure 27] It is a sectional view showing the configuration of the secondary battery according to Embodiment 2. [Figure 28] It is a perspective view showing the configuration of the current collector included in the secondary battery according to Embodiment 3. [Figure 29] It is a sectional view taken along line XXIX-XXIX of the current collector shown in FIG. 28. [Figure 30] It is a perspective view showing the configuration of the current collector included in the secondary battery according to Embodiment 4. [Figure 31] It is a sectional view taken along line XXXI-XXXI of the current collector shown in FIG. 30. [Figure 32] It is a perspective view showing the configuration of the current collector included in the secondary battery according to Embodiment 5. [Figure 33] It is a sectional view taken along line XXXIII-XXXIII of the current collector shown in FIG. 32. [Figure 34] It is a perspective view showing the configuration of the current collector included in the secondary battery according to Embodiment 6. [Figure 35] It is a sectional view taken along line XXXV-XXXV of the current collector shown in FIG. 34. [Figure 36] It is a sectional view showing the configuration of the current collector included in the secondary battery according to Embodiment 7.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present technology will be described. In some cases, the same or corresponding parts may be denoted by the same reference numerals and the description thereof will not be repeated.

[0011] 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.

[0012] 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.

[0013] 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).

[0014] In this specification, “secondary battery” is not limited to lithium-ion batteries, but may include other secondary 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.

[0015] In the drawings, the direction along the winding axis of the electrode body of the secondary battery is defined as the X direction, the short side of the electrode body as viewed from the X direction is defined as the Y direction, and the long side of the electrode body as viewed from the X direction is defined as the Z direction. Furthermore, in order to facilitate understanding of the invention, the dimensions of each component in the drawings have been altered from the actual dimensions in some cases.

[0016] In this specification, the X direction may be referred to as the "width direction" of the secondary battery or case body, the Y direction as the "thickness direction" of the secondary battery or case body, and the Z direction as the "height direction" of the secondary battery or case body.

[0017] (Embodiment 1) (Overall battery configuration) Figure 1 is a front view of the secondary battery 1 according to this embodiment. Figures 2 to 5 show the secondary battery 1 shown in Figure 1 as viewed from the directions of arrows II, III, IV, and V, respectively. Figure 6 is a front cross-sectional view of the secondary battery 1 shown in Figure 1.

[0018] The secondary battery 1 can be installed in electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs), etc. However, the use of the secondary battery 1 is not limited to automotive applications.

[0019] As shown in 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 first sealing plate 120, and a second sealing plate 130.

[0020] 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.

[0021] 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.

[0022] As shown in Figures 1 and 2, a first sealing plate 120 and a second sealing plate 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 laser welding). The corners of the "rectangular tube" may have a rounded shape.

[0023] 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.

[0024] 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.

[0025] 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 gas exhaust valve 150 can be modified as appropriate.

[0026] 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.

[0027] 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.

[0028] As shown in Figure 3, a first opening 113 is provided at the first side end of the case body 110 in the first direction (X direction). The first opening 113 is sealed by a first sealing plate 120. A joint portion 115 is formed in the first opening 113 to seal it. The first opening 113 and the first sealing plate 120 have a substantially rectangular shape with a longitudinal direction and a transverse direction in the direction intersecting the first direction (X direction) in which the first opening 113 and the second opening 114 are aligned. In this embodiment, the first opening 113 and the first sealing plate 120 have a substantially rectangular shape with the Y direction being the transverse direction and the Z direction being the longitudinal direction. Note that the substantially rectangular shape includes a rectangular shape, or a rectangular shape with rounded corners, etc.

[0029] A negative electrode terminal 301 (first electrode terminal) is provided on the first sealing plate 120. The position of the negative electrode terminal 301 can be changed as appropriate.

[0030] As shown in Figure 4, a second opening 114 is provided at the end of the case body 110 on the second side opposite to the first side in the first direction (X direction). That is, the second opening 114 is located at the end opposite to the first opening 113. The second opening 114 is sealed by a second sealing plate 130. A joint 115 is formed in the second opening 114 to seal it. The second opening 114 and the second sealing plate 130 have a substantially rectangular shape with a longitudinal direction and a transverse direction in the direction that intersects the first direction (X direction) in which the first opening 113 and the second opening 114 are aligned. In this embodiment, the second opening 114 and the second sealing plate 130 have a substantially rectangular shape with the transverse direction being the transverse direction in the Y direction and the transverse direction being the longitudinal direction in the Z direction.

[0031] A positive electrode terminal 302 (second electrode terminal) and an injection hole 134 are provided on the second sealing plate 130. The positions of the positive electrode terminal 302 and the injection hole 134 can be changed as appropriate.

[0032] The first sealing plate 120 and the second sealing plate 130 are made of metal. Specifically, the first sealing plate 120 and the second sealing plate 130 are made of aluminum, aluminum alloy, iron, or iron alloy, etc.

[0033] The negative electrode terminal 301 is electrically connected to the negative electrode (first electrode) of the electrode body 200. The negative electrode terminal 301 is attached to the first sealing plate 120, i.e., the case 100.

[0034] The positive terminal 302 is electrically connected to the positive electrode (second electrode) of the electrode body 200. The positive terminal 302 is attached to the second sealing plate 130, i.e., the case 100.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The electrode body 200 is a flat-shaped electrode body having a positive electrode plate and a negative electrode plate, which will be described later. Specifically, the electrode body 200 is a wound-type electrode body in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound together via a strip-shaped separator (not shown). However, in this specification, "electrode body" is not limited to a wound-type electrode body, and may also be a laminated-type electrode body in which multiple positive electrode plates and multiple negative electrode plates are alternately stacked. The strip-shaped separator can be made of, for example, a polyolefin microporous film. The electrode body may include multiple positive electrode plates and multiple negative electrode plates, and positive electrode tabs provided on each positive electrode plate may be stacked to form a group of positive electrode tabs, or negative electrode tabs provided on each negative electrode plate may be stacked to form a group of negative electrode tabs. The electrode body 200 may include multiple wound-type electrode bodies, or it may include multiple laminated-type electrode bodies.

[0039] 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 winding axis is parallel to the X direction.

[0040] Specifically, one or more wound 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 diethyl carbonate (DEC) 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. Alternatively, a solid electrolyte may be used instead of the electrolyte.

[0041] The first electrode body 201 includes a main body (a portion in which a positive electrode plate and a negative electrode plate are stacked with a separator in between), a first electrode tab 220 (a group of negative electrode tabs), and a second electrode tab 250 (a group of positive electrode tabs).

[0042] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240, which will be described later. The first electrode tab 220 is located at the first side end of the first electrode body 201 in a first direction (X direction) relative to the main body. In this embodiment, the first side is the side of the first sealing plate 120. The second electrode tab 250 is located at the second side end of the first electrode body 201 in a first direction (X direction) relative to the main body. In this embodiment, the second side is the side of the second sealing plate 130.

[0043] The first electrode tab 220 and the second electrode tab 250 are formed to protrude from the central portion of the electrode body 200 toward the first sealing plate 120 or the second sealing plate 130, respectively.

[0044] 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.

[0045] The negative electrode current collector 400A is positioned on the first sealing plate 120 via a resin insulating member. The negative electrode current collector 400A is electrically connected to the first electrode tab 220 and the negative electrode terminal 301. The negative electrode current collector 400A is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. Further details of the negative electrode current collector 400A will be described later.

[0046] The positive electrode current collector 400B is positioned on the second sealing plate 130 via a resin insulating member. The positive electrode current collector 400B is electrically connected to the second electrode tab 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 second electrode tab 250 may be electrically connected to the second sealing plate 130 directly or via the positive electrode current collector 400B. In this case, the second sealing plate 130 may also function as the positive electrode terminal 302. Further details of the positive electrode current collector 400B will be described later.

[0047] (Configuration of electrode body 200) Figure 7 is a front view showing the negative electrode base plate 210S before the negative electrode plate 210 (first electrode) is formed, Figure 8 is a cross-sectional view of the negative electrode base plate 210S shown in Figure 7, and Figure 9 is a front view showing the negative electrode plate 210 formed from the negative electrode base plate 210S.

[0048] The negative electrode plate 210 is manufactured by processing the negative electrode base plate 210S. As shown in Figures 7 and 8, the negative electrode base plate 210S includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is copper foil or copper alloy foil.

[0049] The negative electrode core body 211 has a negative electrode active material layer 212 formed on both sides, except for one end. The negative electrode active material layer 212 is formed by applying a negative electrode active material slurry using a die coater.

[0050] The negative electrode active material layer slurry is prepared by kneading graphite as the negative electrode active material, styrene-butadiene rubber (SBR) and carboxymethylcellulose (CMC) as binders, and water as a dispersion medium, so that the mass ratio of graphite:SBR:CMC is approximately 98:1:1.

[0051] The negative electrode core 211, to which the negative electrode active material layer slurry has been applied, is dried to remove water contained in the negative electrode active material layer slurry, thereby forming the negative electrode active material layer 212. Furthermore, by compressing the negative electrode active material layer 212, a negative electrode base plate 210S containing the negative electrode core 211 and the negative electrode active material layer 212 is formed. The negative electrode plate 210 is formed by cutting the negative electrode base plate 210S into a predetermined shape. The negative electrode base plate 210S can be cut by laser processing using energy beam irradiation, mold processing, or cutter processing.

[0052] As shown in Figure 9, a plurality of negative electrode tabs 230, each made of a negative electrode core 211, are provided at one end in the width direction of the negative electrode plate 210 formed from the negative electrode base plate 210S. When the negative electrode plate 210 is wound, the plurality of negative electrode tabs 230 are stacked to form the first electrode tab 220. As a result, the first electrode tab 220 is connected to the negative electrode plate 210 (first electrode). The position and protruding length of each of the plurality of negative electrode tabs 230 are appropriately adjusted considering the state in which the first electrode tab 220 is connected to the negative electrode current collector 400A. Note that the shape of the negative electrode tab 230 is not limited to that illustrated in Figure 8.

[0053] Figure 10 is a front view showing the positive electrode base plate 240S before the positive electrode plate 240 (second electrode) is formed, Figure 11 is a cross-sectional view of the positive electrode base plate 240S shown in Figure 10 from line XI, and Figure 12 is a front view showing the positive electrode plate 240 formed from the positive electrode base plate 240S.

[0054] The positive electrode plate 240, which is the second electrode, has a different polarity from the negative electrode plate 210, which is the first electrode. The positive electrode plate 240 is manufactured by processing a positive electrode base plate 240S. As shown in Figures 10 and 11, the positive electrode base plate 240S includes a positive electrode core 241, a positive electrode active material layer 242, and a positive electrode protective layer 243. The positive electrode core 241 is aluminum foil or aluminum alloy foil.

[0055] A positive electrode active material layer 242 is formed on the positive electrode core 241, except for one end on both sides. The positive electrode active material layer 242 is formed on the positive electrode core 241 by applying a positive electrode active material slurry using a die coater.

[0056] The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as the positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium, such that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material is approximately 97.5:1:1.5.

[0057] The positive electrode protective layer 243 is in contact with the positive electrode core 241 and is formed on one end of the positive electrode active material layer 242 in the width direction. The positive electrode protective layer 243 is formed on the positive electrode core 241 by applying a positive electrode protective layer slurry with a die coater. The positive electrode protective layer 243 has an electrical resistance greater than that of the positive electrode active material layer 242.

[0058] The positive electrode protective layer slurry is prepared by kneading alumina powder, carbon material as a conductive material, PVdF as a binder, and NMP as a dispersion medium, such that the mass ratio of alumina powder:carbon material:PVdF is approximately 83:3:14.

[0059] The positive electrode core 241, to which the positive electrode active material layer slurry and positive electrode protective layer slurry have been applied, is dried to remove NMP contained in the positive electrode active material layer slurry and positive electrode protective layer slurry, thereby forming the positive electrode active material layer 242 and positive electrode protective layer 243. Furthermore, by compressing the positive electrode active material layer 242, a positive electrode base plate 240S containing the positive electrode core 241, positive electrode active material layer 242, and positive electrode protective layer 243 is formed. The positive electrode plate 240 is formed by cutting the positive electrode base plate 240S into a predetermined shape. The positive electrode base plate 240S can be cut by laser processing using energy beam irradiation, mold processing, or cutter processing.

[0060] As shown in Figure 12, a plurality of positive electrode tabs 260, each made of a positive electrode core 241, are provided at one end in the width direction of the positive electrode plate 240 formed from the positive electrode base plate 240S. When the positive electrode plate 240 is wound, the plurality of positive electrode tabs 260 are stacked to form a second electrode tab 250. As a result, the second electrode tab 250 is connected to the positive electrode plate 240 (second electrode). The position and protruding length of each of the plurality of positive electrode tabs 260 are appropriately adjusted considering the state in which the second electrode tab 250 is connected to the positive electrode current collector 400B. Note that the shape of the positive electrode tab 260 is not limited to that exemplified in Figure 12.

[0061] A positive electrode protective layer 243 is provided at the base of each of the multiple positive electrode tabs 260. However, a positive electrode protective layer 243 is not necessarily provided at the base of each positive electrode tab 260.

[0062] In a typical example, the thickness of the negative electrode tab 230 (one piece) is less than the thickness of the positive electrode tab 260 (one piece). In this case, the thickness of the first electrode tab 220 is less than the thickness of the second electrode tab 250.

[0063] (Connection structure between electrode body 200 and current collector 400) Figure 13 is a cross-sectional view of the secondary battery shown in Figure 1 along line XIII-XIII. As shown in Figure 13, 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 first electrode (negative electrode) and a second electrode (positive electrode). The electrode body 200 may be composed of three or more electrode bodies.

[0064] 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.

[0065] The first electrode body 201 includes a first electrode tab 220. The first electrode tab 220 is electrically connected to the first electrode at a first end 205 on the first sealing plate 120 side in the X direction. The second electrode body 202 includes a third electrode tab 270. The third electrode tab 270 is electrically connected to the first electrode at a third end 207 on the first sealing plate 120 side in the X direction.

[0066] The first electrode tab 220 has a curved portion 221 and a tip portion 222. The curved portion 221 is the part of the first electrode tab 220 that is curved relative to the tip portion 222 on the side to which the first electrode is connected. The tip portion 222 is the end of the first electrode tab 220 that is located on the side opposite to the side to which the first electrode is connected.

[0067] The third electrode tab 270 has a curved portion 271 and a tip portion 272. The curved portion 271 is the part of the third electrode tab 270 that is curved relative to the tip portion 272 on the side to which the first electrode is connected. The tip portion 272 is the end of the third electrode tab 270 that is located on the side opposite to the side to which the first electrode is connected.

[0068] The first electrode tab 220 and the third electrode tab 270 are each curved in opposite directions so 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.

[0069] The negative electrode current collector 400A electrically connects the negative electrode terminal 301 to the first electrode tab 220 and the third electrode tab 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 first sealing plate 120.

[0070] The negative electrode current collector 400A includes a first current collector 410, a third current collector 430, and a fifth current collector 450.

[0071] The first current collector 410 is a plate-shaped member. The first current collector 410 has a longitudinal direction in the Z direction and a short direction in the Y direction. The third current collector 430 is a plate-shaped member. The third current collector 430 has a longitudinal direction in the Z direction and a short direction in the Y direction. The first current collector 410 and the third current collector 430 are arranged in parallel in the Y direction. Thus, the first current collector 410 and the third current collector 430 are composed of separate parts.

[0072] The first electrode tab 220 is joined to the first current collector 410 at a joining point 411, which will be described later. The third electrode tab 270 is joined to the third current collector 430 at a joining point 431, which will be described later. The joining points 411 and 431 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, crimping, etc. In this embodiment, the first electrode tab 220 and the first current collector 410, and the third electrode tab 270 and the third current collector 430 are joined by, for example, ultrasonic welding.

[0073] The fifth current collector 450 is electrically connected to the first current collector 410 and the third current collector 430 at a joint located at its Z-direction end, as described later. The fifth current collector 450 is electrically connected to the negative terminal 301. The connection between the fifth current collector 450 and the negative terminal 301 can be formed, for example, by crimping and / or welding.

[0074] The negative electrode terminal 301 is exposed on the outside of the first sealing plate 120 and is positioned to reach the fifth current collector 450 of the negative electrode current collector 400A, which is located on the inner surface side of the first sealing plate 120. The negative electrode terminal 301 is connected to the first plate portion 303.

[0075] The first plate portion 303 is located on the outside of the first sealing plate 120. The first plate portion 303 is arranged along the first sealing plate 120. The first plate portion 303 is conductive. The first plate portion 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 first plate portion 303 can be formed, for example, by laser welding.

[0076] A first insulating member 510 is placed between the first plate portion 303 and the first sealing plate 120. A second insulating member 520 is placed between the negative terminal 301 and the first sealing plate 120. A third insulating member 530 is placed between the fifth current collector 450 and the first sealing plate 120.

[0077] However, the negative terminal 301 may be electrically connected to the first sealing plate 120. Alternatively, the first sealing plate 120 may also function as the negative terminal 301.

[0078] A spacer 600 is positioned between the first sealing plate 120 and the electrode body 200. The spacer 600 is made of an insulating resin material. The spacer 600 includes a first component 610 and a second component 620. The first component 610 and the second component 620 are engaged with each other at engaging portions (not shown) at both ends in the Z direction.

[0079] The first component 610 and the second component 620 protrude in the Y direction at their ends on the electrode body 200 side in the X direction. As a result, the spacer 600 acts as a guide to facilitate the bending of the curved portions 221 and 271 when they are bent.

[0080] 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).

[0081] Figure 14 is an XIV-XIV cross-sectional view of the secondary battery shown in Figure 1. The first electrode body 201 includes a second electrode tab 250. The second electrode tab 250 is electrically connected to the second electrode at a second end 206 on the second sealing plate 130 side in the X direction. The second electrode body 202 includes a fourth electrode tab 280. The fourth electrode tab 280 is electrically connected to the second electrode at a fourth end 208 on the second sealing plate 130 side in the X direction.

[0082] The second electrode tab 250 has a curved portion 251 and a tip portion 252. The curved portion 251 is the part of the second electrode tab 250 that is curved relative to the tip portion 252 on the side to which the second electrode is connected. The tip portion 252 is the end of the second electrode tab 250 that is located on the side opposite to the side to which the second electrode is connected.

[0083] The fourth electrode tab 280 has a curved portion 281 and a tip portion 282. The curved portion 281 is the part of the fourth electrode tab 280 that is curved relative to the tip portion 282 on the side to which the second electrode is connected. The tip portion 282 is the end of the fourth electrode tab 280 that is located on the side opposite to the side to which the second electrode is connected.

[0084] The second electrode tab 250 and the fourth electrode tab 280 are each curved in opposite directions so that their tips 252 and 282 are closer to each other. In this embodiment, the tips 252 and 282 are spaced apart, but the configuration is not limited to this, and the tips 252 and 282 may be in contact with each other.

[0085] The positive electrode current collector 400B electrically connects the positive electrode terminal 302 to the second electrode tab 250 and the fourth electrode tab 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 second sealing plate 130.

[0086] The positive electrode current collector 400B includes a second current collector 420, a fourth current collector 440, and a sixth current collector 460.

[0087] The second current collector 420 is a plate-shaped member. The second current collector 420 has a longitudinal direction in the Z direction and a short direction in the Y direction. The fourth current collector 440 is a plate-shaped member. The fourth current collector 440 has a longitudinal direction in the Z direction and a short direction in the Y direction. The second current collector 420 and the fourth current collector 440 are arranged in parallel in the Y direction. Thus, the second current collector 420 and the fourth current collector 440 are composed of separate parts.

[0088] The second electrode tab 250 is joined to the second current collector 420 at a joining point 421, which will be described later. The fourth electrode tab 280 is joined to the fourth current collector 440 at a joining point 441, which will be described later. The joining points 421 and 441 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, crimping, etc. In this embodiment, the second electrode tab 250 and the second current collector 420, and the fourth electrode tab 280 and the fourth current collector 440 are joined by, for example, ultrasonic welding.

[0089] The sixth current collector 460 is electrically connected to the second current collector 420 and the fourth current collector 440 at a joint located at its end in the Z direction, as described later. The sixth current collector 460 is electrically connected to the positive terminal 302. The connection between the sixth current collector 460 and the positive terminal 302 can be formed, for example, by crimping and / or welding.

[0090] The positive terminal 302 is exposed on the outside of the second sealing plate 130 and is positioned to reach the sixth current collector 460 of the positive current collector 400B, which is located on the inner surface side of the second sealing plate 130. The positive terminal 302 is connected to the second plate portion 304.

[0091] The second plate portion 304 is located on the outside of the second sealing plate 130. The second plate portion 304 is arranged along the second sealing plate 130. The second plate portion 304 is conductive. The second plate portion 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 second plate portion 304 can be formed, for example, by laser welding.

[0092] A first insulating member 510 is placed between the second plate portion 304 and the second sealing plate 130. A second insulating member 520 is placed between the positive terminal 302 and the second sealing plate 130. A third insulating member 530 is placed between the sixth current collector 460 and the second sealing plate 130.

[0093] However, the positive terminal 302 may be electrically connected to the second sealing plate 130. Alternatively, the second sealing plate 130 may also function as the positive terminal 302.

[0094] A spacer 600 is positioned between the second sealing plate 130 and the electrode body 200. The spacer 600 is made of an insulating resin material. The spacer 600 includes a first component 610 and a second component 620. The first component 610 and the second component 620 are engaged with each other at engaging portions (not shown) at both ends in the Z direction.

[0095] The first component 610 and the second component 620 protrude in the Y direction at their ends on the electrode body 200 side in the X direction. As a result, the spacer 600 acts as a guide to facilitate the bending of the curved portions 251 and 281 when they are bent.

[0096] A resin insulating sheet 700 (electrode holder) is placed between the electrode body 200 and the case body 110.

[0097] (Manufacturing process for secondary battery 1) The method for manufacturing a secondary battery according to this embodiment will be described below. Figure 15 is a flowchart showing the method for manufacturing a secondary battery according to Embodiment 1. Figure 16 is a perspective view showing the state before the two electrode bodies of the secondary battery according to Embodiment 1 overlap.

[0098] As shown in Figure 15, 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). A portion of the tip of each of the first electrode tab 220, the second electrode tab 250, the third electrode tab 270, and the fourth electrode tab 280 is cut so that when the tips are bundled together they are all the same length.

[0099] As shown in Figures 15 and 16, after the first electrode body 201 and the second electrode body 202 are manufactured, the first electrode tab 220 is joined to the first current collector 410 (step S2). The first electrode tab 220 is joined to the first current collector 410 at the joining point 411. Next, the second electrode tab 250 is joined to the second current collector 420 (step S3). The second electrode tab 250 is joined to the second current collector 420 at the joining point 421. Next, the third electrode tab 270 is joined to the third current collector 430 (step S4). The third electrode tab 270 is joined to the third current collector 430 at the joining point 431. Next, the fourth electrode tab 280 is joined to the fourth current collector 440 (step S5). The fourth electrode tab 280 is joined to the fourth current collector 440 at the joining point 441.

[0100] In the height direction of the first electrode body 201 and the second electrode body 202, the first current collector 410, the second current collector 420, the third current collector 430, and the fourth current collector 440 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.

[0101] However, the first current collector 410, the second current collector 420, the third current collector 430, and the fourth current collector 440 are not limited to this configuration. The first current collector 410, the second current collector 420, the third current collector 430, and the fourth current collector 440 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. In this case, in the height direction of the first electrode body 201 and the second electrode body 202, the first electrode tab 220, the second current collector 420, the third current collector 430, and the fourth current collector 440, respectively, the first electrode tab 220, the second electrode tab 250, the third electrode tab 270, and the fourth electrode tab 280 are each positioned in the center of the first electrode body 201 and the second electrode body 202.

[0102] Furthermore, the order in which the first current collector 410, the second current collector 420, the third current collector 430, and the fourth current collector 440 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.

[0103] Figure 17 is a cross-sectional view showing the electrode tabs folded. As shown in Figures 15 to 17, the first electrode body 201 and the second electrode body 202 are then superimposed in the thickness direction of the first electrode body 201 and the second electrode body 202 (step S6). The first electrode body 201 and the second electrode body 202 are superimposed along the direction of the arrow in Figure 16. In other words, the first electrode body 201 and the second electrode body 202 are combined into one.

[0104] "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. Furthermore, the first electrode and the second electrode may or may not be fixed with tape or the like.

[0105] Fold the first electrode tab 220, second electrode tab 250, third electrode tab 270, and fourth electrode tab 280 in the direction of the arrows in Figure 17. This positions the tips of the first electrode tab 220 and the third electrode tab 270 facing each other. Also, the tips of the second electrode tab 250 and the fourth electrode tab 280 are positioned facing each other.

[0106] Furthermore, it is desirable that the step of overlapping the first electrode body 201 and the second electrode body 202 be performed before the step of joining the first current collector 410, the second current collector 420, the third current collector 430, and the fourth current collector 440 to the first electrode body 201 and the second electrode body 202. Alternatively, the step of overlapping the first electrode body 201 and the second electrode body 202 may be performed in the middle of each of the steps of joining the first current collector 410, the second current collector 420, the third current collector 430, and the fourth current collector 440.

[0107] Figure 18 is a perspective view showing the electrode body with the holder and spacer attached. As shown in Figures 15 and 18, the spacer 600 and insulating sheet 700 are then assembled onto the electrode body 200 (step S7).

[0108] The insulating sheet 700 does not necessarily need to cover the entire surface of the electrode body 200. Preferably, the insulating sheet 700 covers an area of ​​50% or more, more preferably 70% or more, of the outer surface of the electrode body. Preferably, the insulating sheet 700 covers the entirety of four of the six surfaces of the substantially rectangular parallelepiped (flat-shaped) electrode body 200, excluding the two surfaces on which the first electrode tab 220 and the second electrode tab 250 are formed.

[0109] Figure 19 is a perspective view showing the first current collector with the first sealing plate attached. Figure 20 is a cross-sectional view of the electrode body and current collector shown in Figure 19, taken along line XX-XX.

[0110] As shown in Figures 15, 19, and 20, after the first electrode body 201 and the second electrode body 202 are superimposed, the first current collector 410 and the third current collector 430 are connected to the fifth current collector 450 (step S8).

[0111] Furthermore, step S8 can be performed before step S7. Performing step S8 before step S7 makes it easier to make a more stable connection when electrically connecting the negative electrode terminal 301 to the first electrode tab 220 and the third electrode tab 270. It also makes it easier to create a configuration with a smaller space between the first sealing plate 120 and the main body of the electrode body 200.

[0112] The first electrode tab 220 and the third electrode tab 270 are bent so that their tips 222 and 272 face each other.

[0113] The negative electrode terminal 301 and the fifth current collector 450 are attached to the first sealing plate 120 via an insulating member. The fifth current collector 450 is brought into contact with the first current collector 410 and the third current collector 430 in the X direction. The fifth current collector 450 and the first current collector 410 and the third current collector 430 are joined by laser welding from between the first sealing plate 120 and the insulating sheet 700. Note that the connection of the first plate portion 303 to the negative electrode terminal 301 can be done at any time.

[0114] The connection of the first current collector 410, the third current collector 430, and the fifth current collector 450 can take the same welded connection configuration as the second current collector 420, the fourth current collector 440, and the sixth current collector 460 described later.

[0115] Specifically, a third overlapping region is defined where the first current collector 410 and the fifth current collector 450 overlap each other at the longitudinal end of the first sealing plate 120 (upper end in the Z direction), viewed from the longitudinal direction (Y direction) of the first sealing plate 120. Furthermore, a fourth overlapping region is defined where the third current collector 430 and the fifth current collector 450 overlap each other at the longitudinal end of the first sealing plate 120 (upper end in the Z direction), viewed from the longitudinal direction (Y direction) of the first sealing plate 120.

[0116] In the third overlapping region, the first current collector 410 and the fifth current collector 450 are welded together. Also, in the fourth overlapping region, the third current collector 430 and the fifth current collector 450 are welded together.

[0117] Figure 21 is a perspective view showing the electrode body inserted into the case body. As shown in Figures 15 and 21, the first current collector 410 and the third current collector 430 are then connected to the fifth current collector 450, and the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 through the first opening 113, with the second electrode tab 250 and the fourth electrode tab 280 sides leading (step S9).

[0118] The first sealing plate 120 is brought into contact with the case body 110. This causes the first electrode tab 220 and the third electrode tab 270 to bend. As shown in Figure 13, the first electrode tab 220 and the third electrode tab 270 are bent along the shape of the spacer 600 so that the folded portions of the curved parts 221 and 271 approach the case body 110 in the Y direction.

[0119] Subsequently, the first sealing plate 120 is temporarily joined to the case body 110. This temporary joining partially joins the first sealing plate 120 to the first opening 113 of the case body 110. This positions the first sealing plate 120 relative to the case body 110.

[0120] When inserting the electrode body 200 into the case body 110, the electrode body 200 may be pulled from the second current collector 420 and the fourth current collector 440 side, or pushed from the first current collector 410 and the third current collector 430 side. When the electrode body 200 is pushed from the first current collector 410 and the third current collector 430 side, the first electrode tab 220 and the third electrode tab 270 can be bent at the same time.

[0121] Figure 22 is a perspective view showing the second current collector with the second sealing plate attached. Figure 23 is a cross-sectional view of the electrode body and current collector shown in Figure 22 along line XXIII-XXIII. Figure 24 is a view of the current collector shown in Figure 22 from the direction of arrow XXIV. Figure 25 is a cross-sectional view of the current collector shown in Figure 24 along line XXV-XXV. Note that the case body 110 is omitted in Figure 23.

[0122] As shown in Figures 15 and 22-25, the first electrode body 201 and the second electrode body 202 are then inserted into the case body 110, and the second current collector 420 and the fourth current collector 440, which protrude from the second opening 114, are connected to the sixth current collector 460 (step S10).

[0123] Specifically, the positive terminal 302 and the sixth current collector 460 are attached to the second sealing plate 130 via an insulating member. The sixth current collector 460 is brought into contact with the second current collector 420 in the X direction. Note that the connection of the second plate portion 304 to the positive terminal 302 can be made at any time.

[0124] As shown in Figures 24 and 25, each of the second current collector 420, the fourth current collector 440, and the sixth current collector 460 in this embodiment has a folded portion F at its end in the Z direction. The folded portion F is aligned with the X direction. Because the folded portion F is aligned with the X direction, the high-energy rays 2 can be irradiated from a direction parallel to the Z direction, thus making it possible to configure the device in a way that the high-energy rays 2 are less likely to interfere with the case body 110 or the second sealing plate 130. The high-energy rays are, for example, laser light.

[0125] When viewed from the longitudinal direction (Y direction) of the second sealing plate 130, the second current collector 420 and the sixth current collector 460 overlap each other at their longitudinal ends, forming a first overlapping region R11. The first overlapping region R11 is formed by the alignment of the folded portions F in the Z direction.

[0126] Furthermore, when viewed from the longitudinal direction (Y direction) of the second sealing plate 130, the fourth current collector 440 and the sixth current collector 460 overlap each other at their longitudinal ends, forming a second overlapping region R12. The second overlapping region R12 is formed because the folded portions F are aligned in the Z direction.

[0127] When connecting the second current collector 420 and the fourth current collector 440 to the sixth current collector 460, high-energy rays 2 are irradiated onto at least one of the second current collector 420 and the sixth current collector 460 from between the second sealing plate 130 and the end of the case body 110 on the second opening 114 side, thereby welding the second current collector 420 and the sixth current collector 460. In addition, high-energy rays 2 are irradiated onto at least one of the fourth current collector 440 and the sixth current collector 460 from between the second sealing plate 130 and the end of the case body 110 on the second opening 114 side, thereby welding the fourth current collector 440 and the sixth current collector 460.

[0128] In the first overlapping region R11, the second current collector 420 and the sixth current collector 460 are welded together. In this embodiment, the second current collector 420 and the sixth current collector 460 are welded together at the welding position P1 in the first overlapping region R11.

[0129] In the second overlapping region R12, the fourth current collector 440 and the sixth current collector 460 are welded together. In this embodiment, the fourth current collector 440 and the sixth current collector 460 are welded together at the welding position P2 in the second overlapping region R12.

[0130] The welding method between the second current collector 420 or the fourth current collector 440 and the sixth current collector 460 is, for example, through welding. The sixth current collector 460 may have a thin-walled portion, and the current collectors may be welded together at the thin-walled portion, or the sixth current collector 460 may have a through hole, and the current collectors may be welded together at a position away from the through hole.

[0131] The second electrode tab 250 and the fourth electrode tab 280 are bent so that their tips 252 and 282 face each other. The second sealing plate 130 is brought into contact with the case body 110. This causes the second electrode tab 250 and the fourth electrode tab 280 to bend. As shown in Figure 14, the second electrode tab 250 and the fourth electrode tab 280 are bent along the shape of the spacer 600 so that the folded portions of the bent parts 251 and 281 approach the case body 110 in the Y direction.

[0132] Subsequently, the second sealing plate 130 is tack-welded to the case body 110. This tack-welding partially joins the second sealing plate 130 to the second opening 114 of the case body 110. This positions the second sealing plate 130 relative to the case body 110.

[0133] Figure 26 is a perspective view showing the configuration of a secondary battery according to Embodiment 1. As shown in Figures 15 and 26, the first sealing plate 120 and the second sealing plate 130 are then joined to the case body 110 (step S11). The first sealing plate 120 seals the first opening 113 of the case body 110, and the second sealing plate 130 seals the second 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.

[0134] After the above steps, inspections such as leak testing are performed (step S12). After the leak testing, the secondary battery 1 is dried to remove moisture from inside the case 100. Then, electrolyte is injected into the inside of the case 100 through the injection hole 134. When injecting the electrolyte, the case 100 is tilted with the second sealing plate 130 facing upwards and the first sealing plate 120 facing downwards, and the electrolyte is injected into the inside of the case 100 through the injection hole 134 of the second sealing plate 130. After that, degassing and charging are performed. During degassing and charging, the injection hole 134 may be temporarily sealed. After that, the injection hole is sealed, and the secondary battery 1 is completed.

[0135] In the secondary battery 1 and its manufacturing method according to Embodiment 1 of this technology, by providing a first electrode tab 220 and a second electrode tab 250 on the first electrode body 201, and a third electrode tab 270 and a fourth electrode tab 280 on the second electrode body 202, a configuration can be made in which the first electrode body 201 and the second electrode body 202 have separate electrode tabs. With this configuration, the electrode tab can be shortened compared to the case in which the first electrode body 201 and the second electrode body 202 form a single electrode tab and this electrode tab is bent. As a result, the volume occupied by the electrode tab can be reduced, and the energy density of the secondary battery 1 can be improved. Furthermore, the configuration in which the first electrode body 201 and the second electrode body 202 have separate electrode tabs makes the electrode tab easier to bend compared to the case in which the first electrode body 201 and the second electrode body 202 form a single electrode tab, making it easier to connect the electrode tab to the current collector and enabling the stable manufacture of the secondary battery. In particular, the ability to stably manufacture secondary batteries 1 makes it possible to improve the reliability of the connection between the electrode tabs and the current collector.

[0136] In the secondary battery 1 and its manufacturing method according to Embodiment 1 of this technology, by providing a first overlapping region R11 where the second current collector 420 and the sixth current collector 460 overlap, and a second overlapping region R12 where the fourth current collector 440 and the sixth current collector 460 overlap, a region in which current collectors can be joined together can be secured, thereby enabling stable connection of the current collectors. When connecting the current collectors by irradiating them with high-energy rays 2 from between the second opening 114 of the case body 110 and the second sealing plate 130, it is possible to easily secure a weldable range between the current collectors when irradiated with high-energy rays 2 from a second direction (Z direction) that intersects the first direction in which the first opening 113 and the second opening 114 are aligned.

[0137] In the secondary battery 1 and its manufacturing method according to Embodiment 1 of this technology, by providing a third overlapping region where the first current collector 410 and the fifth current collector 450 overlap, and a fourth overlapping region where the third current collector 430 and the fifth current collector 450 overlap, a region in which current collectors can be joined together can be secured, thereby enabling stable connection of current collectors. When connecting current collectors by irradiating them with high-energy rays from between the first opening 113 of the case body 110 and the first sealing plate 120, it is possible to easily secure a weldable range between current collectors when irradiated with high-energy rays from a second direction (Z direction) that intersects the first direction in which the first opening 113 and the second opening 114 are aligned.

[0138] In the manufacturing method of the secondary battery 1 according to Embodiment 1 of this technology, a high-energy ray 2 is irradiated onto at least one of the second current collector 420 and the sixth current collector 460 from between the second sealing plate 130 and the end of the case body 110 on the second opening 114 side to weld the second current collector 420 and the sixth current collector, and a high-energy ray 2 is irradiated onto at least one of the fourth current collector 440 and the sixth current collector 460 to weld the fourth current collector 440 and the sixth current collector 460, thereby enabling a stable connection of the current collectors on the second opening 114 side after the electrode body 200 has been inserted into the case body 110.

[0139] The secondary battery according to Embodiment 2 will now be described. Since the connection structure between the electrode body and the current collector of the secondary battery according to Embodiment 2 differs from that of the secondary battery 1 according to Embodiment 1 of this technology, the same configuration as that of the secondary battery 1 according to Embodiment 1 of this technology will not be repeated in the description.

[0140] (Embodiment 2) Figure 27 is a cross-sectional view showing the configuration of a secondary battery according to Embodiment 2. As shown in Figure 27, in the secondary battery according to Embodiment 2, the tips 222A and 272A of the first electrode tab 220A and the third electrode tab 270A are bent in the same direction in the Y direction.

[0141] Subsequently, the first electrode body 201A and the second electrode body 202A are inserted into the case body, and the first sealing plate 120 is brought into contact with the case body. As a result, the first electrode tab 220A and the third electrode tab 270A each curve in the same direction so that the tips 222A and 272A located at the end opposite to the side to which the first electrode is connected face the same direction. To facilitate the curving of the tips 222A and 272A in the same direction, a third component 630A of the spacer 600A is provided between the first electrode tab 220A and the third electrode tab 270A.

[0142] By ensuring that the tips 222A and 272A of the first electrode tab 220A and the third electrode tab 270A are curved in the same direction in the Y-direction, and that the tips of the second electrode tab and the fourth electrode tab are curved in the same direction in the Y-direction, the first electrode body 201A, to which the first current collector 410 and the second current collector 420 are attached, and the second electrode body 202A, to which the third current collector 430 and the fourth current collector 440 are attached, can be prepared with the same configuration. This makes it easier to manufacture the first electrode body 201A, to which the first current collector 410 and the second current collector 420 are attached, and the second electrode body 202A, to which the third current collector 430 and the fourth current collector 440 are attached, as a single type.

[0143] The secondary batteries according to Embodiments 3 to 7 will be described below. Since the connection structure between the current collectors in the secondary batteries according to Embodiment 1 of this technology differs from that of the secondary battery 1 according to Embodiment 1 of this technology, the same configuration as the secondary battery 1 according to Embodiment 1 of this technology, and the same configuration between Embodiments 3 to 7 will not be repeated in the description.

[0144] (Embodiment 3) Figure 28 is a perspective view showing the configuration of the current collector of the secondary battery according to Embodiment 3. Figure 29 is a cross-sectional view of the current collector shown in Figure 28, taken along line XXIX-XXIX.

[0145] As shown in Figures 28 and 29, each of the second current collector 420B, the fourth current collector 440B, and the sixth current collector 460B in this embodiment has a folded portion F at its end in the Z direction. The folded portion F is folded in a convex shape that slopes from the YZ plane toward the case body 110.

[0146] Each of the second current collector 420B, the fourth current collector 440B, and the sixth current collector 460B has a gap G1 in the flat plate portion other than the folded portion F. This makes it easier for the current collectors to come into contact with each other at the folded portion F. In addition, a reaction force is applied toward the current collector due to the bending of the electrode tabs. This allows the current collectors to be brought into close contact with each other.

[0147] In the secondary battery and its manufacturing method according to Embodiment 3 of this technology, by providing a first overlapping region R31 where the second current collector 420B and the sixth current collector 460B overlap, and a second overlapping region R32 where the fourth current collector 440B and the sixth current collector 460B overlap, a region in which current collectors can be joined together can be secured, thereby enabling stable connection of the current collectors. When connecting the current collectors by irradiating them with high-energy rays 2 from between the second opening 114 of the case body 110 and the second sealing plate 130, it is possible to easily secure a weldable range between the current collectors when irradiated with high-energy rays 2 from a direction intersecting the first direction in which the first opening 113 and the second opening 114 are aligned.

[0148] (Embodiment 4) Figure 30 is a perspective view showing the configuration of the current collector of the secondary battery according to Embodiment 4. Figure 31 is a cross-sectional view of the current collector shown in Figure 30, taken along line XXXI-XXXI.

[0149] As shown in Figures 30 and 31, each current collector in this embodiment has a folded portion F at its end in the Z direction. An extension E extending in the Z direction is provided at the tip of the folded portion F.

[0150] The sixth current collector 460C has a gap G2 at its extension E. This allows for a greater distance between each current collector and the insulating material, thus reducing the transfer of heat to the insulating material when the current collectors are joined together with high-energy rays.

[0151] The extensions E of the second current collector 420C and the sixth current collector 460C come into contact with each other, forming a first contact region R41 that extends in directions (Y and Z directions) intersecting the first direction (X direction) in which the first opening 113 and the second opening 114 are aligned, and in which the second current collector 420C and the sixth current collector 460C come into contact in the first direction (X direction). The first contact region R41 includes the contact surfaces of the second current collector 420C and the sixth current collector 460C. The first contact region R41 extends on a plane that intersects the first direction (X direction). The first contact region R41 extends in the Y direction and the Z direction, respectively. It is preferable that the first contact region R41 is positioned along the second sealing plate 130.

[0152] Furthermore, the extensions E of the fourth current collector 440C and the sixth current collector 460C come into contact with each other, forming a second contact region R42 that extends in directions (Y and Z directions) intersecting the first direction (X direction), and in which the fourth current collector 440C and the sixth current collector 460C come into contact in the first direction (X direction).

[0153] At the end of the first contact region R41, the second current collector 420C and the sixth current collector 460C are welded together. At the end of the second contact region R42, the fourth current collector 440C and the sixth current collector 460C are welded together.

[0154] The connection of current collectors on the first sealing plate 120 side of the secondary battery is configured in the same way as the connection of current collectors on the second sealing plate 130 side.

[0155] Specifically, a third contact region is formed extending in a direction intersecting the first direction, where the first current collector and the fifth current collector abut in the first direction (X direction). A fourth contact region is formed extending in a direction intersecting the first direction, where the third current collector and the fifth current collector abut in the first direction. At the end of the third contact region, the first current collector and the fifth current collector are welded together. At the end of the fourth contact region, the third current collector and the fifth current collector are welded together.

[0156] In the secondary battery and its manufacturing method according to Embodiment 4 of this technology, by providing a first contact region R41 and a second contact region R42, a region where current collectors can be joined together can be secured, making it easier to stably connect current collectors to each other. In particular, the joining points between current collectors can be secured without requiring high precision in the relative positioning of the current collectors to be joined.

[0157] In the secondary battery and its manufacturing method according to Embodiment 4 of this technology, by providing a third contact region and a fourth contact region, a region in which the first current collector or the third current collector and the fifth current collector can be joined can be secured, making it easier to stably connect the current collectors to each other.

[0158] (Embodiment 5) Figure 32 is a perspective view showing the configuration of the current collector of the secondary battery according to Embodiment 5. Figure 33 is a cross-sectional view of the current collector shown in Figure 32 along line XXXIII-XXXIII.

[0159] As shown in Figures 32 and 33, each of the second current collector 420D, the fourth current collector 440D, and the sixth current collector 460D in this embodiment has a folded portion F at its end in the Z direction. An extension portion E extending in the Z direction is provided at the tip of the folded portion F. The tip of the extension portion E is bent in a direction away from the current collectors that are joined together. Since the contact portion of the extension portion E is inward from the tip, welding sagging is less likely to occur.

[0160] (Embodiment 6) Figure 34 is a perspective view showing the configuration of the current collector of the secondary battery according to Embodiment 6. Figure 35 is a cross-sectional view of the current collector shown in Figure 34, taken along the line XXXV-XXXV.

[0161] As shown in Figures 34 and 35, the sixth current collector 460E in this embodiment has a greater thickness in the X direction compared to the second current collector 420E and the fourth current collector 440E. This allows the sixth current collector 460E to have a larger heat capacity when joining the current collectors with high-energy rays 2, thus making it more difficult for the heat generated when joining the current collectors with high-energy rays to be transferred to the insulating material.

[0162] The second current collector 420E and the fourth current collector 440E are provided with a fuse section 422E. If the current collector overheats, the fuse section 422E, which is as far away as possible from the insulating material of the positive electrode current collector, will preferentially melt.

[0163] (Embodiment 7) Figure 36 is a cross-sectional view showing the configuration of the current collector in the secondary battery according to Embodiment 7.

[0164] As shown in Figure 36, the sixth current collector 460F in this embodiment has a greater thickness in the X direction compared to the second current collector 420F and the fourth current collector. The sixth current collector 460F has a gap G3 at the extended portion E located on the tip side of the folded portion F. This allows for a greater distance from the insulating member, making it more difficult for heat to be transferred to the insulating member when the current collectors are joined together with high-energy rays 2.

[0165] In the secondary battery and its manufacturing method according to embodiments 5 to 7 of this technology, by providing first contact regions R51, R61, R71 and second contact regions R52, R62, a region where current collectors can be joined together can be secured, making it easier to stably connect current collectors to each other. In particular, the connection point between current collectors can be secured without requiring high precision in the relative positioning of the current collectors to be joined.

[0166] Preferably, the first sealing plate 120 and the second sealing plate 130 each have a pair of long edges arranged parallel to each other and a short edge that is shorter than the pair of long edges arranged parallel to each other. In this case, the direction in which the pair of long edges extend is the longitudinal direction.

[0167] 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]

[0168] 1 Secondary battery, 2 High-energy rays, 100 Case, 110 Case body, 111 First side section, 112, 112A, 112B Second side section, 113 First opening, 114 Second opening, 115 Joint, 120 First sealing plate, 130 Second sealing plate, 134 Injection hole, 150 Gas discharge valve, 200, 200A Electrode body, 201, 201A First electrode body, 202, 202A Second electrode body, 205 First end, 206 Second end, 207 Third end, 208 Fourth end, 210 Negative electrode plate, 210S Negative electrode base plate, 211 Negative electrode core, 212 Negative electrode active material layer, 220, 220A First electrode tab, 221, 251, 271, 281 Curved section, 222, 222A, 252, 272, 272A, 282 Tip section, 230 Negative electrode tab, 240 Positive electrode plate, 240S Positive electrode base plate, 241 Positive electrode core, 242 Positive electrode active material layer, 243 Positive electrode protective layer, 250 Second electrode tab, 260 Positive electrode tab, 270, 270A Third electrode tab, 280 Fourth electrode tab, 300 Electrode terminal, 301 Negative electrode terminal, 302 Positive electrode terminal, 303 First plate section, 304 Second plate section, 400 Current collector, 400A Negative electrode current collector, 400B Positive electrode current collector, 410 First current collector, 411, 421, 431, 441 Joint locations: 420, 420B, 420C, 420D, 420E, 420F Second current collector: 422E Fuse section: 430 Third current collector: 440, 440B, 440C, 440D, 440E Fourth current collector: 450 Fifth current collector: 460, 460B, 460C, 460D, 460E, 460F Sixth current collector: 510 First insulating member: 520 Second insulating member: 530 Third insulating member: 600, 600A Spacer: 610 First component: 620 Second component: 630A Third component: 700 Insulating sheet: E Extension section: F Folded section: G1, G2, G3 Gap: P1, P2 Welding position: R11, R31 First overlapping region: R12, R32 Second overlapping region: R41, R51, R61, R71. First contact region: R42, R52, R62. Second contact region.

Claims

1. An electrode body comprising a first electrode, a second electrode having a different polarity from the first electrode, a first electrode tab electrically connected to the first electrode, and a second electrode tab electrically connected to the second electrode, A case comprising a case body having a first opening at one end and a second opening at the other end, a first sealing plate that seals the first opening, and a second sealing plate that seals the second opening, for housing the electrode body, A first current collector member electrically connected to the first electrode tab, A second current collector connected to the first current collector, The device comprises a first electrode terminal electrically connected to the second current collector and provided on the first sealing plate, The end of the electrode body on the side of the first sealing plate is provided with a first tab group including a plurality of first electrode tabs and a second tab group including a plurality of first electrode tabs. The first current collector member includes a first member and a second member, The second electrode tab is positioned at the end of the electrode body on the second sealing plate side, in a method for manufacturing a secondary battery. 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 current collector member electrically connected to the first electrode via a first electrode tab and a second current collector member electrically connected to the first electrode terminal. The step of joining the first current collector and the second current collector includes irradiating at least one of the first current collector and the second current collector with a high-energy ray from between the case body and the first sealing plate, thereby joining the first current collector and the second current collector. A method for manufacturing a secondary battery, wherein the first tab group and the first member are connected, and the second tab group and the second member are connected, and the first member and the second current collector, and the second member and the second current collector, are joined together.

2. A second electrode terminal is provided on the second sealing plate. A method for manufacturing a secondary battery according to claim 1, further comprising the step of electrically connecting the second electrode tab to the second electrode terminal.

3. A second electrode terminal is provided on the second sealing plate. A method for manufacturing a secondary battery according to claim 1 or 2, wherein the second electrode terminal and the second electrode tab provided on the second sealing plate are electrically connected before inserting the electrode body into the case body.

Images