Manufacturing method of secondary batteries

Abstract

The present invention provides a method for manufacturing secondary batteries that enables the stable and efficient production of secondary batteries with high energy density and high reliability. [Solution] The method comprises the steps of: manufacturing an electrode body including a first electrode and a second electrode, having a group of first electrode tabs electrically connected to the first electrode at a first end, and a group of second electrode tabs connected to the second electrode at a second end opposite to the first end; electrically connecting the first electrode terminal provided on a first sealing plate to the group of first electrode tabs; joining the group of second electrode tabs to a first conductive member; inserting the electrode body into the case body from the second end side through a first opening after joining the group of second electrode tabs to the first conductive member; electrically connecting the second electrode terminal provided on a second sealing plate to the group of second electrode tabs; sealing the first opening with the first sealing plate after connecting the first electrode terminal to the group of first electrode tabs; and sealing the second opening with the second sealing plate after connecting the second electrode terminal to the group of second electrode tabs.

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when manufacturing the secondary battery described in Patent Document 1, when housing the electrode group (25) in the case (14) having openings (14a, 14b) at both ends, the electrode tab group on the leading side in the insertion direction may inhibit insertion. Also, unintended deformation may occur in the electrode tab group. From the viewpoint of stably and efficiently manufacturing a highly reliable secondary battery, there is room for further improvement in the battery described in Patent Document 1.

[0005] From a different perspective, further improvement in the energy density of secondary batteries is required. From the viewpoint of improving the energy density, there is also room for further improvement in the battery described in Patent Document 1.

[0006] An object of this technology is to provide a method for manufacturing a secondary battery capable of stably and efficiently manufacturing a secondary battery with a high energy density and high reliability.

Means for Solving the Problems

[0007] This technology provides the following method for manufacturing secondary batteries.

[0008] The process involves: preparing a case body having a first opening and a second opening opposite the first opening; manufacturing an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode, having a group of first electrode tabs electrically connected to the first electrode at a first end and a group of second electrode tabs electrically connected to the second electrode at a second end opposite to the first end; electrically connecting the first electrode terminal provided on the first sealing plate to the group of first electrode tabs; and joining the group of second electrode tabs to the first conductive member. A method for manufacturing a secondary battery, comprising the steps of: joining the second electrode tab group to the first conductive member, then inserting the electrode body into the case body from the second end side through the first opening; electrically connecting the second electrode terminal provided on the second sealing plate to the second electrode tab group; electrically connecting the first electrode terminal to the first electrode tab group, then sealing the first opening with the first sealing plate; and electrically connecting the second electrode terminal to the second electrode tab group, then sealing the second opening with the second sealing plate. [Effects of the Invention]

[0009] According to the secondary battery manufacturing method of this technology, in the step of inserting the electrode body into the case body, the second electrode tab group is bonded to the first conductive member in advance, thereby suppressing unintended deformation (unintended bending, etc.) of the electrode tab group. As a result, secondary batteries can be manufactured stably and efficiently.

[0010] Thus, this technology provides a method for manufacturing secondary batteries that enables the stable and efficient production of secondary batteries with high energy density and high reliability. [Brief explanation of the drawing]

[0011] [Figure 1] This is a front view of a rechargeable battery. [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 secondary battery shown in FIG. 1 as seen from the direction of arrow III. [Figure 4] It is a view showing the secondary battery shown in FIG. 1 as seen from the direction of arrow IV. [Figure 5] It is a front sectional view of the secondary battery shown in FIG. 1. [Figure 6] It is a front view showing the negative electrode raw plate before the negative electrode plate is formed. [Figure 7] It is a VII-VII sectional view of the negative electrode raw plate shown in FIG. 6. [Figure 8] It is a front view showing the negative electrode plate formed from the negative electrode raw plate. [Figure 9] It is a front view showing the positive electrode raw plate before the positive electrode plate is formed. [Figure 10] It is an X-X sectional view of the positive electrode raw plate shown in FIG. 9. [Figure 11] It is a front view showing the positive electrode plate formed from the positive electrode raw plate. [Figure 12] It is a view showing the electrode body and the current collector taken out from the secondary battery. [Figure 13] It is a view showing the connection structure between the negative electrode tab group and the negative electrode current collector. [Figure 14] It is a front view of the connection structure shown in FIG. 13. [Figure 15] It is a sectional view of the connection structure shown in FIG. 13. [Figure 16] It is a view showing the step of inserting the electrode body into the case body. [Figure 17] It is a view showing the step of disposing a spacer between the sealing plate and the electrode body. [Figure 18] It is a sectional view showing the state where a spacer is disposed between the sealing plate and the electrode body. [Figure 19] It is a view showing the connection structure between the positive electrode tab group and the positive electrode current collector. [Figure 20] It is a sectional view of the connection structure shown in FIG. 19. [Figure 21] It is a flowchart showing each step of the manufacturing method of the secondary battery.

Mode for Carrying Out the Invention

[0012] The embodiments of the present technology will be described below. In the following description, the same or corresponding parts may be denoted by the same reference numerals, and the description thereof may not be repeated.

[0013] In the embodiments described below, when referring to the number, amount, etc., unless otherwise specified, the scope of the present technology is not necessarily limited to such number, amount, etc. Further, in the following embodiments, each component is not necessarily essential for the present technology, unless otherwise specified. Also, the present technology is not necessarily limited to those that exhibit all of the effects described in the present embodiments.

[0014] In this specification, the descriptions of "comprise", "include", and "have" are in an open-ended form. That is, when including a certain configuration, other configurations outside the said configuration may or may not be included.

[0015] Also, in this specification, when geometric terms and terms representing positional and directional relationships, such as "parallel", "orthogonal", "diagonal 45°", "coaxial", "along", etc., are used, those terms allow for manufacturing errors or slight variations. In this specification, when terms representing relative positional relationships such as "upper side" and "lower side" are used, those terms are used to indicate the relative positional relationship in one state, and the relative positional relationship can be reversed or rotated at an arbitrary angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0016] In this specification, "battery" is not limited to a lithium-ion battery and may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "electrode" may be a general term for a positive electrode and a negative electrode. Also, "electrode plate" may be a general term for a positive electrode plate and a negative electrode plate.

[0017] (Overall configuration of the battery) Figure 1 is a front view of the secondary battery 1 according to this embodiment. Figures 2 to 4 show the secondary battery 1 shown in Figure 1 as viewed from the directions of arrows II, III, and IV, respectively. Figure 5 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 5, the secondary battery 1 includes an outer casing 100, an electrode body 200, and a current collector 300. The outer casing 100 includes a case body 110, a sealing plate 121 (first sealing plate), and a sealing plate 122 (second sealing plate).

[0020] In this specification, the X-axis direction (first direction) shown in Figures 1 to 5 may be referred to as the "width direction" of the secondary battery 1 to the case body 110, the Y-axis direction (second direction) may be referred to as the "thickness direction" of the secondary battery 1 to the case body 110, and the Z-axis direction (third direction) may be referred to as the "height direction" of the secondary battery 1 to the case body 110.

[0021] 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-axis 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.

[0022] 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.

[0023] As shown in Figures 1 and 2, sealing plates 121 and 122 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 110A 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.

[0024] In this embodiment, the case body 110 is formed to be longer in the width direction (X-axis direction) of the secondary battery 1 than in the thickness direction (Y-axis direction) and height direction (Z-axis direction) of the secondary battery 1. The dimension (width) of the case body 110 in the X-axis 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-axis 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.

[0025] As shown in Figure 3, an opening 111 (first opening) is provided at one end of the case body 110. The opening 111 is sealed by a sealing plate 121. The sealing plate 121 is provided with a negative electrode terminal 131 (first electrode terminal), an injection hole 141, and a gas discharge valve 151. The positions of the negative electrode terminal 131, the injection hole 141, and the gas discharge valve 151 can be changed as appropriate. The opening 111 and the sealing plate 121 have a substantially rectangular shape with the Y-axis direction being the short side and the Z-axis direction being the long side.

[0026] As shown in Figure 4, an opening 112 (second opening) is provided at one end of the case body 110. The opening 112 is sealed by a sealing plate 122. The sealing plate 122 is provided with a positive electrode terminal 132 (second electrode terminal), an injection hole 142, and a gas discharge valve 152. The positions of the positive electrode terminal 132, the injection hole 142, and the gas discharge valve 152 can be changed as appropriate. The opening 112 and the sealing plate 122 have a substantially rectangular shape with the Y-axis direction being the short side and the Z-axis direction being the long side.

[0027] The sealing plates 121 and 122 are made of metal. Specifically, the sealing plates 121 and 122 are made of aluminum, aluminum alloy, iron, or iron alloy, etc.

[0028] The negative terminal 131 is electrically connected to the negative electrode of the electrode body 200. The positive terminal 132 is electrically connected to the positive electrode of the electrode body 200.

[0029] The negative electrode terminal 131 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 131.

[0030] The positive terminal 132 is made of a conductive material (more specifically, a metal), which may be made of aluminum or an aluminum alloy, for example.

[0031] The injection holes 141 and 142 are sealed by a sealing member (not shown). For example, blind rivets and other metal members can be used as the sealing member.

[0032] The gas discharge valves 151 and 152 rupture when the pressure inside the outer casing 100 exceeds a predetermined value, thereby discharging the gas inside the outer casing 100 to the outside.

[0033] 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 stacked alternately. 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.

[0034] As shown in Figure 5, the outer casing 100 houses the electrode body 200. The electrode body 200 is housed within the outer casing 100 such that its winding axis is parallel to the X-axis direction.

[0035] Specifically, one or more wound electrode bodies are housed inside the insulating sheet 600 (described later) placed within the outer casing 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.

[0036] The electrode body 200 includes a negative electrode tab group 210A (first electrode tab group) provided at the end (first end) on the sealing plate 121 side, and a positive electrode tab group 220A (second electrode tab group) provided at the end (second end) on the sealing plate 122 side. The negative electrode tab group 210A and the positive electrode tab group 220A are connected to the negative electrode and positive electrode of the electrode body 200, respectively. The negative electrode tab group 210A and the positive electrode tab group 220A are formed to protrude toward the sealing plates 121 and 122, respectively, from the main body portion of the electrode body 200 (the portion in which the positive electrode plate and the negative electrode plate are stacked with a separator in between).

[0037] The current collector 300 includes a negative electrode current collector 310 (first current collector) and a positive electrode current collector 320 (second current collector). The negative electrode current collector 310 and the positive electrode current collector 320 are each made of plate-shaped members. The electrode body 200 is electrically connected to the negative electrode terminal 131 and the positive electrode terminal 132 via the current collector 300.

[0038] The negative electrode current collector 310 is positioned on the sealing plate 121 via a resin insulating member 410. The negative electrode current collector 310 is electrically connected to the negative electrode tab group 210A and the negative electrode terminal 131. The negative electrode current collector 310 is made of a conductive material (more specifically, a metal), which may be made of copper or a copper alloy, for example.

[0039] The positive electrode current collector 320 is positioned on the sealing plate 122 via a resin insulating member 420. The positive electrode current collector 320 is electrically connected to the positive electrode tab group 220A and the positive electrode terminal 132. The positive electrode current collector 320 is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy. The positive electrode tab group 220A may be electrically connected to the sealing plate 122 directly or via the positive electrode current collector 320. In this case, the sealing plate 122 may also serve as the positive electrode terminal 132.

[0040] (Configuration of electrode body 200) Figure 6 is a front view showing the negative electrode base plate 210S before the negative electrode plate 210 (first electrode) is formed, Figure 7 is a VII-VII cross-sectional view of the negative electrode base plate 210S shown in Figure 6, and Figure 8 is a front view showing the negative electrode plate 210 formed from the negative electrode base plate 210S.

[0041] The negative electrode plate 210 is manufactured by processing the negative electrode base plate 210S. As shown in Figures 6 and 7, 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] As shown in Figure 8, a plurality of negative electrode tabs 210B, 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 210B are stacked to form a negative electrode tab group 210A. The position and protruding length of each of the plurality of negative electrode tabs 210B are appropriately adjusted considering the state in which the negative electrode tab group 210A is connected to the negative electrode current collector 310. Note that the shape of the negative electrode tabs 210B is not limited to that exemplified in Figure 8.

[0046] Figure 9 is a front view showing the positive electrode base plate 220S before the positive electrode plate 220 (second electrode) is formed, Figure 10 is a cross-sectional view of the positive electrode base plate 220S shown in Figure 9, and Figure 11 is a front view showing the positive electrode plate 220 formed from the positive electrode base plate 220S.

[0047] The positive electrode plate 220 is manufactured by processing the positive electrode base plate 220S. As shown in Figures 9 and 10, the positive electrode base plate 220S includes a positive electrode core 221, a positive electrode active material layer 222, and a positive electrode protective layer 223. The positive electrode core 221 is aluminum foil or aluminum alloy foil.

[0048] A positive electrode active material layer 222 is formed on the positive electrode core 221, except for one end on both sides. The positive electrode active material layer 222 is formed on the positive electrode core 221 by applying a positive electrode active material slurry using a die coater.

[0049] 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.

[0050] The positive electrode protective layer 223 is in contact with the positive electrode core 221 and is formed on one end of the positive electrode active material layer 222 in the width direction. The positive electrode protective layer 223 is formed on the positive electrode core 221 by applying a positive electrode protective layer slurry with a die coater. The positive electrode protective layer 223 has an electrical resistance greater than that of the positive electrode active material layer 222.

[0051] 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.

[0052] The positive electrode core 221, 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 222 and the positive electrode protective layer 223. Furthermore, by compressing the positive electrode active material layer 222, a positive electrode base plate 220S containing the positive electrode core 221, the positive electrode active material layer 222, and the positive electrode protective layer 223 is formed. The positive electrode plate 220 is formed by cutting the positive electrode base plate 220S into a predetermined shape. The positive electrode base plate 220S can be cut by laser processing using energy beam irradiation, mold processing, or cutter processing.

[0053] As shown in Figure 11, a plurality of positive electrode tabs 220B, each consisting of a positive electrode core 221, are provided at one end in the width direction of the positive electrode plate 220 formed from the positive electrode base plate 220S. When the positive electrode plate 220 is wound, the plurality of positive electrode tabs 220B are stacked to form a group of positive electrode tabs 220A. The position and protruding length of each of the plurality of positive electrode tabs 220B are appropriately adjusted considering the state in which the group of positive electrode tabs 220A is connected to the positive electrode current collector 320. Note that the shape of the positive electrode tabs 220B is not limited to that shown in Figure 11.

[0054] A positive electrode protective layer 223 is provided at the base of each of the multiple positive electrode tabs 220B. However, a positive electrode protective layer 223 is not necessarily provided at the base of each positive electrode tab 220B.

[0055] In a typical example, the thickness of one negative electrode tab 210B is smaller than the thickness of one positive electrode tab 220B. In this case, the thickness of the negative electrode tab group 210A is smaller than the thickness of the positive electrode tab group 220A.

[0056] (Connection structure between electrode body 200 and current collector 300) Figure 12 shows the electrode body 200 and current collector 300 taken from the secondary battery 1. As shown in Figure 12, the electrode body 200 is formed by stacking two electrode bodies 201 and 202, each being a wound-type electrode body. In the example shown in Figure 12, a structure in which two wound-type electrode bodies are stacked is shown, but the electrode body 200 may be composed of one wound-type electrode body, or of three or more wound-type electrode bodies, or of a stacked electrode body.

[0057] The negative electrode tab group 210A is joined to the negative electrode current collector 310 at joint 310A, and the positive electrode tab group 220A is joined to the positive electrode current collector 320 at joint 320A. The joints 310A and 320A can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, etc. The joints 310A and 320A constitute a conductive path between the negative electrode tab group 210A and the positive electrode tab group 220A and the negative electrode terminal 131 and the positive electrode terminal 132.

[0058] (Connection structure between electrode body 200 and negative electrode current collector 310) Figure 13 shows the connection structure between the negative electrode tab group 210A and the negative electrode current collector 310. Figures 14 and 15 are a front view and a cross-sectional view, respectively, of the connection structure shown in Figure 13.

[0059] As shown in Figures 13 to 15, the negative electrode current collector 310 is connected to the negative electrode terminal 131 between the electrode body 200 and the sealing plate 121. The negative electrode current collector 310 includes a first conductive member 311 and a second conductive member 312. The first conductive member 311 and the second conductive member 312 are joined at a joint 313.

[0060] The negative electrode tab group 210A is joined to the first conductive member 311 of the negative electrode current collector 310 at the joint 310A. The first conductive member 311 is connected to the second conductive member 312 at the joint 313. The joint 313 can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, etc.

[0061] The first conductive member 311 and the second conductive member 312 are attached to the inner surface of the sealing plate 121 via a resin insulating member 410.

[0062] The negative electrode terminal 131 is attached to the sealing plate 121 via a resin insulating member 410A. The negative electrode terminal 131 is exposed on the outside of the sealing plate 121 and is positioned to reach the second conductive member 312 of the negative electrode current collector 310, which is provided on the inner surface side of the sealing plate 121. The negative electrode terminal 131 and the second conductive member 312 can be connected by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, etc. In this embodiment, a through hole is provided in the second conductive member 312, the negative electrode terminal 131 is inserted into the through hole, the negative electrode terminal 131 is crimped on the second conductive member 312, and then the crimped portion and the second conductive member 312 are welded at the joint 131A to connect the negative electrode terminal 131 and the second conductive member 312.

[0063] The assembly procedure for each component is as follows: First, the negative electrode terminal 131 and the second conductive member 312 are attached to the sealing plate 121 together with the insulating members 410 and 410A. Next, the first conductive member 311, which is connected to the electrode body 200, is attached to the second conductive member 312. At this time, the first conductive member 311 is positioned on the insulating member 410 such that a part of the first conductive member 311 overlaps with the second conductive member 312. Subsequently, the first conductive member 311 and the second conductive member 312 are welded together at the joint 313. Note that the insulating members 410 and 410A may be composed of a single piece.

[0064] However, the negative terminal 131 may be electrically connected to the sealing plate 121. Alternatively, the sealing plate 121 may also function as the negative terminal 131.

[0065] In Figures 13 to 15, a negative electrode current collector 310 consisting of two parts (a first conductive member 311 and a second conductive member 312) is shown as an example, but the negative electrode current collector 310 may also be composed of a single part.

[0066] (Insertion process of electrode body 200) Figure 16 shows the process of inserting the electrode body 200 into the case body 110. As shown in Figure 16, a resin insulating sheet 600 (electrode body holder) is placed between the electrode body 200 and the case body 110.

[0067] The insulating sheet 600 may be made of, for example, a resin. More specifically, the material of the insulating sheet 600 may be, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0068] The insulating sheet 600 does not necessarily need to cover the entire surface of the electrode body 200. Preferably, the insulating sheet 600 covers an area of ​​50% or more, more preferably 70% or more, of the outer surface of the electrode body. Preferably, the insulating sheet 600 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 negative electrode tab group 210A and the positive electrode tab group 220A are formed, respectively.

[0069] Figure 17 shows the process of placing the spacer 510 between the sealing plate 121 and the electrode body 200. Figure 18 is a cross-sectional view showing the state in which the spacer 510 is placed between the sealing plate 121 and the electrode body 200.

[0070] As shown in Figures 17 and 18, the group of negative electrode tabs 210A extending from the electrode body 200 to the sealing plate 121 is curved so that it extends from the center of the sealing plate 121 in the Y-axis direction toward the end, and then folds back toward the center in the opposite direction. The spacer 510 is positioned to accommodate the curved group of negative electrode tabs 210A (curved portion).

[0071] The spacer 510 includes a first spacer 511 and a second spacer 512. The first spacer 511 and the second spacer 512 engage with each other by sliding along the Y-axis from the end side to the center side of the sealing plate 121. This fixes the spacer 510 to the sealing plate 121 via the insulating member 410, increasing the stability of the spacer 510's position.

[0072] As shown in Figure 18, the spacer 510 forms an internal space for housing the negative electrode current collector 310, and the tip portions of the negative electrode tab group 210A are also housed in the internal space of the spacer 510. The spacer 510 has a hole through which the negative electrode tab group 210A can pass.

[0073] The material of the spacer 510 is not particularly limited, but it is preferable to use an insulating material such as resin. More specifically, it is preferable to use a sheet made of polyolefin (PO). Alternatively, an insulating sheet 600 may be interposed between the spacer 510 and the electrode body 200.

[0074] Referring again to Figure 16, in the manufacturing method of the secondary battery 1 according to this embodiment, the positive electrode tab group 220A is joined to the first conductive member 321 of the positive electrode current collector 320, and then the electrode body 200 is inserted into the case body 110 from the end side of the positive electrode tab group 220A.

[0075] When the electrode body 200 is inserted into the case body 110 through the opening 111, unintended deformation may occur in the positive electrode tab group 220A located at the front. In contrast, by joining the positive electrode tab group 220A to the first conductive member 321 of the positive electrode current collector 320 before inserting the electrode body 200 into the case body 110, unintended deformation of the positive electrode tab group 220A can be suppressed. As a result, it becomes possible to manufacture a highly reliable secondary battery 1 stably and efficiently.

[0076] Furthermore, in the example shown in Figure 16, the electrode body 200 is inserted into the case body 110 while covered with an insulating sheet 600. This helps to suppress damage to the electrode body 200 when it is inserted into the case body 110.

[0077] Furthermore, in the example shown in Figure 16, after electrically connecting the negative electrode terminal 131 and the negative electrode tab group 210A, the electrode body 200 is inserted into the case body 110 from the end side of the positive electrode tab group 220A through the opening 111. When electrically connecting the negative electrode terminal 131 attached to the sealing plate 121 and the negative electrode tab group 210A after inserting the electrode body 200 into the case body 110, the negative electrode tab group 210A needs to be long enough so that the negative electrode tab group 210A of the electrode body 200 housed in the case body 110 protrudes sufficiently outside the case body 110. By electrically connecting the negative electrode terminal 131 attached to the sealing plate 121 and the negative electrode tab group 210A before inserting the electrode body 200 into the case body 110, the length of the negative electrode tab group 210A can be reduced compared to when the connection is made after inserting the electrode body 200 into the case body 110. As a result, the volume occupancy ratio of the negative electrode plate 210 and the positive electrode plate 220 within the internal space of the case body 110 can be increased.

[0078] The case body 110 can be held at a predetermined angle during the electrode body 200 insertion process. For example, it is preferable to insert the electrode body 200 while holding the case body 110 so that the X-axis direction (width direction of the case body 110) intersects the horizontal direction at an angle of approximately ±45° or less. For example, the case body 110 can be tilted so that in the vertical direction, the upper end of the opening 111 into which the electrode body 200 is inserted is located above the upper end of the opening 112, and the electrode body 200 can be inserted into the case body 110.

[0079] The electrode insertion step is not limited to pushing the electrode 200 in from the opening 111 side, but may also be performed by pulling the electrode 200 from the opening 112 side, for example.

[0080] (Connection structure between electrode body 200 and positive electrode current collector 320) Figure 19 shows the connection structure between the positive electrode tab group 220A and the positive electrode current collector 320. Figure 20 is a cross-sectional view of the connection structure shown in Figure 19.

[0081] As shown in Figures 19 and 20, the positive electrode current collector 320 is provided on the inner surface side of the sealing plate 122 and is connected to the electrode body 200 and the positive electrode terminal 132. The positive electrode current collector 320 includes a first conductive member 321 (first component) and a second conductive member 322 (second component). The first conductive member 321 and the second conductive member 322 are joined at a joint 323. The first conductive member 321 and the second conductive member 322 are attached to the inner surface side of the sealing plate 122 via a resin insulating member 420.

[0082] The first conductive member 321 has a stepped portion 321A. The stepped portion 321A extends in the direction of the long side (Z-axis direction) of the rectangular sealing plate 122. As shown in Figure 20, in the region on one side of the stepped portion 321A (the left side in Figure 20) (the first region), the first conductive member 321 is provided along the sealing plate 122 and is joined to the positive electrode tab group 220A (joint portion 320A). In the region on the other side of the stepped portion 321A (the right side in Figure 20) (the second region), the first conductive member 321 is provided so as to overlap with the second conductive member 322. These configurations are the same on the negative electrode side (see Figures 13 to 15).

[0083] Figures 19 and 20 show the shape of the positive electrode tab group 220A before it is curved. In the completed secondary battery 1, the positive electrode tab group 220A is housed in the case body 110 in a curved state. It is preferable to curve (shape) the positive electrode tab group 220A to a state close to its final shape before housing the electrode body 200 in the case body 110.

[0084] The positive electrode tab group 220A is joined to the first conductive member 321 of the positive electrode current collector 320 at the joint 320A. The first conductive member 321 is connected to the second conductive member 322 at the joint 323. The joint 323 can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, etc.

[0085] The positive electrode terminal 132 is attached to the sealing plate 122 via a resin insulating member 420A. The positive electrode terminal 132 is exposed on the outside of the sealing plate 122 and is positioned to reach the second conductive member 322 of the positive electrode current collector 320, which is provided on the inner surface side of the sealing plate 122. The positive electrode terminal 132 and the second conductive member 322 can be connected by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, etc. In this embodiment, a through hole is provided in the second conductive member 322, the positive electrode terminal 132 is inserted into the through hole, the positive electrode terminal 132 is crimped on the second conductive member 322, and then the crimped portion and the second conductive member 322 are welded at the joint portion 132A to connect the positive electrode terminal 132 and the second conductive member 322.

[0086] The assembly procedure for each component is as follows: First, the positive terminal 132 and the second conductive member 322 are attached to the sealing plate 122 together with the insulating members 420 and 420A. Next, the first conductive member 321, which is connected to the electrode body 200, is attached to the second conductive member 322. At this time, the first conductive member 321 is positioned on the insulating member 420 such that a part of the first conductive member 321 overlaps with the second conductive member 322. Subsequently, the first conductive member 321 and the second conductive member 322 are welded together at the joint 323. Note that the insulating members 420 and 420A may be composed of a single piece.

[0087] However, the positive terminal 132 may be electrically connected to the sealing plate 122. Alternatively, the sealing plate 122 may also function as the positive terminal 132.

[0088] In Figures 19 and 20, a positive electrode current collector 320 consisting of two components (a first conductive member 321 and a second conductive member 322) is shown as an example, but the positive electrode current collector 320 may also be composed of a single component.

[0089] (Manufacturing process for secondary battery 1) Figure 21 is a flow chart showing each step of the manufacturing method for secondary battery 1. As shown in Figure 21, in S10, the case body 110 is prepared. Next, in S20, the electrode body 200 is manufactured. In S30, the electrode terminals provided on the sealing plates 121 and 122 are electrically connected to the electrode tab group of the electrode body 200. In the example in Figure 21, first the negative electrode terminal 131 and the negative electrode tab group 210A are electrically connected (S31), and then the positive electrode terminal 132 and the positive electrode tab group 220A are electrically connected (S32).

[0090] To electrically connect the positive terminal 132 and the positive tab group 220A, first, the first conductive member 321 of the positive current collector 320 and the positive tab group 220A are joined (S32A), and then the electrode body 200 is inserted into the case body 110 (S40). After the electrode body 200 is inserted into the case body 110, the first conductive member 311 and the second conductive member 312 are joined to electrically connect the positive terminal 132 and the positive tab group 220A (S32B).

[0091] After the connection between the electrode terminals and the electrode tab group (S30) and the insertion of the electrode body 200 (S40) are completed, the openings 111 and 112 are sealed with sealing plates 121 and 122, respectively (S50). The sealing process with sealing plates 121 and 122 is performed, for example, by laser welding.

[0092] In this technology, the order of connecting the negative electrode terminal 131 to the negative electrode tab group 210A (S31), connecting the positive electrode terminal 132 to the positive electrode tab group 220A (S32), and inserting the electrode body 200 (S40) is not limited to the example in Figure 21 and can be changed as appropriate. For example, the connection of the negative electrode terminal 131 to the negative electrode tab group 210A (S31) may be performed after connecting the positive electrode terminal 132 to the positive electrode tab group 220A (S32).

[0093] In the example shown in Figure 21, the process of sealing the opening 111 with the sealing plate 121 on the negative electrode side (S51) is performed first, followed by the process of sealing the opening 112 with the sealing plate 122 on the positive electrode side (S52). However, the process of sealing the opening 111 with the sealing plate 121 (S51) may be performed after the process of sealing the opening 112 with the sealing plate 122 (S52). Furthermore, it is possible to perform at least a portion of the sealing processes using the sealing plates 121 and 122 (S51, S52) simultaneously.

[0094] (summary) The secondary battery 1 according to this embodiment and its manufacturing method can be summarized as follows:

[0095] The manufacturing method of the secondary battery 1 is as shown in Figure 21, and includes the steps of: preparing a case body 110 having an opening 111 and an opening 112 opposite to the opening 111 (S10); and a negative electrode tab group 210 including a negative electrode plate 210 and a positive electrode plate 220, having a negative electrode tab group 210A with a negative electrode tab 210B electrically connected to the negative electrode plate 210 at one end and a positive electrode tab group 220B electrically connected to the positive electrode plate 220 at the other end. The process includes the steps of: manufacturing an electrode body 200 having 0A (S20); electrically connecting electrode terminals provided on sealing plates 121 and 122 with the electrode tab group of the electrode body 200 (S30); inserting the electrode body 200 into the case body 110 from the end side of the positive electrode tab group 220A through the opening 111 (S40); and sealing the openings 111 and 112 with sealing plates 121 and 122, respectively (S50). Here, the positive electrode tab group 220A is joined to the first conductive member 321 of the positive electrode current collector 320 (S32A), and thereafter, the electrode body 200 is inserted into the case body 110 from the end side of the positive electrode tab group 220A through the opening 111 (S40), and the positive electrode terminal 132 provided on the sealing plate 122 is electrically connected to the positive electrode tab group 220A (S32B).

[0096] In one example of a secondary battery 1 manufacturing method, the electrical connection between the positive electrode terminal 132 and the positive electrode tab group 220A is made by joining the first conductive member 321 to the second conductive member 322 provided on the sealing plate 122.

[0097] In one example of a method for manufacturing a secondary battery 1, the electrical connection between the negative electrode terminal 131 and the negative electrode tab group 210A is made by joining the negative electrode tab group 210A to the first conductive member 311 (third conductive member) of the negative electrode current collector 310, and then joining the first conductive member 311 (third conductive member) to the second conductive member 312 (fourth conductive member) provided on the sealing plate 121.

[0098] In one example of a secondary battery 1 manufacturing method, the electrode body 200 may be covered with an insulating sheet 600 before being inserted into the case body 110. However, in this technology, the insulating sheet 600 covering the electrode body 200 is not necessarily required.

[0099] The secondary battery 1 according to this embodiment comprises an electrode body 200 having a negative electrode tab group 210A on the sealing plate 121 side and a positive electrode tab group 220A on the sealing plate 122 side, an outer casing 100 (case) housing the electrode body 200, a negative electrode terminal 131 (first electrode terminal) and a positive electrode terminal 132 (second electrode terminal) provided on the outer casing 100, a negative electrode current collector 310 (first current collector) housed in the outer casing 100 and electrically connecting the negative electrode tab group 210A and the negative electrode terminal 131, and a positive electrode current collector 320 (second current collector) housed in the outer casing 100 and electrically connecting the positive electrode tab group 220A and the positive electrode terminal 132.

[0100] The negative electrode tab group 210A and the positive electrode tab group 220A each have a curved portion. The negative electrode tab group 210A and the positive electrode tab group 220A are joined to the negative electrode current collector 310 and the positive electrode current collector 320, respectively, at joints 310A and 320A located towards the tip of the curved portion. In the region where the joints 310A and 320A are located, the first conductive members 311 and 321 of the negative electrode current collector 310 and the positive electrode current collector 320 are arranged along the sealing plates 121 and 122.

[0101] (Effects and Benefits) According to the secondary battery 1 of this embodiment, by inserting the electrode body 200 into a case body 110 having mutually opposing openings 111 and 112, and providing a negative electrode terminal 131 and a positive electrode terminal 132 on sealing plates 121 and 122 that seal the openings 111 and 112 respectively, the height of the secondary battery 1 can be reduced and the ease of mounting the secondary battery 1 in a vehicle can be improved.

[0102] Furthermore, by arranging the regions where the junctions 310A and 320A of the negative electrode tab group 210A and the positive electrode tab group 220A are located along the sealing plates 121 and 122, respectively, the energy density of the secondary battery 1 can be improved.

[0103] In the manufacturing method of the secondary battery 1 according to this embodiment, the positive electrode tab group 220A is joined to the first conductive member 321 (S32A) before the step of inserting the electrode body 200 into the case body 110 (S40). Therefore, the electrode body 200 can be inserted while suppressing unintended deformation (unintended bending, etc.) of the positive electrode tab group 220A located on the leading side in the insertion direction of the electrode body 200. Thus, the secondary battery 1 can be manufactured stably and efficiently.

[0104] According to the secondary battery 1 of this embodiment, the positive electrode tab group 220A is joined to the first conductive member 321 included in the positive electrode current collector 320, making it easier to implement the above-described manufacturing method of collecting the positive electrode tab group 220A (S32A) before the electrode body 200 insertion step (S40).

[0105] Thus, according to the secondary battery 1 and its manufacturing method in this embodiment, it is possible to stably and efficiently manufacture a secondary battery with high energy density and high reliability.

[0106] 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]

[0107] 1 Secondary battery, 100 Outer casing, 110 Case body, 110A Joint, 111,112 Opening, 121,122 Sealing plate, 131 Negative electrode terminal, 131A Joint, 132 Positive electrode terminal, 132A Joint, 141,142 Injection hole, 151,152 Gas release valve, 200,201,202 Electrode body, 210 Negative electrode plate, 210A Negative electrode tab group, 210B Negative electrode tab, 210S Negative electrode base plate, 211 Negative electrode core, 212 Negative electrode active material layer, 220 Positive electrode plate, 220A Positive electrode tab group, 220B Positive electrode tab, 220S Positive electrode base plate, 221 Positive electrode core, 222 Positive electrode active material layer, 223 Positive electrode protective layer, 300 Current collector, 310 Negative current collector, 310A Joint, 311 First conductive member, 312 Second conductive member, 313 Joint, 320 Positive current collector, 320A Joint, 321 First conductive member, 321A Stepped section, 322 Second conductive member, 323 Joint, 410, 410A, 420, 420A Insulating member, 510 Spacer, 511 First spacer, 512 Second spacer, 600 Insulating sheet.

Claims

1. A step of preparing a case body having a first opening and a second opening facing the first opening, A step of manufacturing an electrode body comprising a first electrode and a second electrode having a polarity different from that of the first electrode, having a group of first electrode tabs electrically connected to the first electrode at a first end, and a group of second electrode tabs electrically connected to the second electrode at a second end opposite to the first end, A step of electrically connecting the first electrode terminal provided on the first sealing plate and the group of first electrode tabs, The steps include joining the second electrode tab group to the first conductive member, The process involves joining the second electrode tab group to the first conductive member, and then inserting the electrode body into the case body from the second end side through the first opening, A step of electrically connecting the second electrode terminal provided on the second sealing plate and the second electrode tab group, The first electrode terminal and the group of first electrode tabs are electrically connected, and the first opening is sealed with the first sealing plate. The process includes the steps of electrically connecting the second electrode terminal and the second electrode tab group, and then sealing the second opening with the second sealing plate, A method for manufacturing a secondary battery, wherein, in the longitudinal direction of the second sealing plate, the length of the first conductive member is greater than the length of the tip of the second electrode tab group.

2. The method for manufacturing a secondary battery according to claim 1, wherein the step of electrically connecting the second electrode terminal and the second electrode tab group includes electrically connecting the first conductive member and the second electrode terminal after inserting the electrode body into the case body.

3. The method for manufacturing a secondary battery according to claim 2, wherein electrically connecting the first conductive member and the second electrode terminal includes joining the first conductive member to the second conductive member attached to the second sealing plate.

4. A method for manufacturing a secondary battery according to any one of claims 1 to 3, wherein the step of electrically connecting the first electrode terminal and the group of first electrode tabs includes joining the group of first electrode tabs to a third conductive member before inserting the electrode body into the case body.

5. The method for manufacturing a secondary battery according to claim 4, wherein the step of electrically connecting the first electrode terminal and the group of first electrode tabs includes electrically connecting the third conductive member and the first electrode terminal before inserting the electrode body into the case body.

6. The method for manufacturing a secondary battery according to claim 5, wherein electrically connecting the third conductive member and the first electrode terminal includes joining the third conductive member to a fourth conductive member attached to the first sealing plate.

7. The first electrode tab group has a curved portion, and the tip end of the first electrode tab group is joined to the third conductive member. The method for manufacturing a secondary battery according to claim 4, wherein the region of the third conductive member joined to the first electrode tab group is arranged along the first sealing plate.

8. The second electrode tab group has a curved portion, and the tip end of the second electrode tab group is joined to the first conductive member. A method for manufacturing a secondary battery according to any one of claims 1 to 3, wherein the region of the first conductive member joined to the second electrode tab group is arranged along the second sealing plate.

9. A method for manufacturing a secondary battery according to any one of claims 1 to 3, further comprising the step of covering the electrode body with an insulating electrode body holder before inserting it into the case body.

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