Secondary battery manufacturing method and secondary battery

Abstract

The invention provides a secondary battery manufacturing method and a secondary battery. This method for manufacturing a secondary battery is provided with: a step in which, after a first electrode body and a second electrode body are made, a second electrode sheet and a fourth electrode sheet are electrically connected to a second current collector in a state in which the first electrode body is disposed on one side of the second current collector and the second electrode body is disposed on the other side of the second current collector; and a step in which, after joining the second electrode sheet and the fourth electrode sheet, the second electrode sheet and the fourth electrode sheet are bent so that the first electrode sheet and the third electrode sheet face each other, thereby overlapping the first electrode body and the second electrode body.

Description

Technical Field

[0001] The present technology relates to a method for manufacturing a secondary battery and the secondary battery. Background Art

[0002] Japanese Patent No. 4537353 discloses a square secondary battery in which an electrode group (25) is housed in a casing (14) having openings (14a, 14b) at both ends and electrode terminals (21, 23) are respectively attached to cover plates (33, 33') for sealing the openings (14a, 14b).

[0003] In the secondary battery described in Japanese Patent No. 4537353, there is still room for improving the energy density and stably manufacturing the secondary battery. Summary of the invention

[0004] The present technology has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a secondary battery and a secondary battery that can improve energy density and can be manufactured stably.

[0005] The present technology provides the following method for manufacturing a secondary battery.

[0006] [1] A method for manufacturing a secondary battery,

[0007] The secondary battery has:

[0008] A first electrode body and a second electrode body, each of which includes a first electrode and a second electrode having a polarity different from that of the first electrode;

[0009] a housing that accommodates the first electrode body and the second electrode body; and

[0010] a first electrode terminal electrically connected to the first electrode,

[0011] The first electrode body includes a first electrode sheet disposed at a first end portion and electrically connected to the first electrode, and a second electrode sheet disposed at a second end portion and electrically connected to the second electrode.

[0012] The second electrode body includes a third electrode sheet disposed at a third end portion and electrically connected to the first electrode, and a fourth electrode sheet disposed at a fourth end portion and electrically connected to the second electrode.

[0013] The first electrode sheet is bonded to the first current collector.

[0014] The second electrode sheet and the fourth electrode sheet are bonded to the second current collector.

[0015] The third electrode sheet is bonded to the third current collector.

[0016] The first current collector and the third current collector are composed of independent components.

[0017] in,

[0018] The manufacturing method of the secondary battery comprises the following steps, namely:

[0019] A step of manufacturing the first electrode body and the second electrode body;

[0020] After the first electrode body and the second electrode body are manufactured, the first electrode sheet is joined to the first current collector;

[0021] After the first electrode body and the second electrode body are manufactured, the third electrode sheet is joined to the third current collector;

[0022] After the first electrode body and the second electrode body are manufactured, a step of electrically connecting the second electrode sheet and the fourth electrode sheet to the second current collector in a state where the first electrode body is disposed on one side of the second current collector and the second electrode body is disposed on the other side of the second current collector;

[0023] After the second electrode sheet and the fourth electrode sheet are bonded to the second current collector, the second electrode sheet and the fourth electrode sheet are bent to overlap the first electrode body and the second electrode body; and

[0024] A step of electrically connecting the first current collector bonded to the first electrode sheet and the third current collector bonded to the third electrode sheet to the first electrode terminal after the first electrode body and the second electrode body are stacked.

[0025] “Overlapping the first electrode body with the second electrode body” means that the first electrode body and the second electrode body may be directly overlapped, or other components may be arranged between the first electrode body and the second electrode body. In addition, the first electrode body and the second electrode body may be fixed by a tape or the like, or may not be fixed. Furthermore, the first electrode body, the second current collector, and the second electrode body may not be arranged on a straight line in one direction, and the first electrode body or the second electrode body may be inclined in one direction relative to the second current collector.

[0026] [2] The method for manufacturing a secondary battery according to [1], wherein:

[0027] The housing includes: a housing body having a first opening; and a first sealing plate for sealing the first opening.

[0028] The first sealing plate is provided with the first electrode terminal.

[0029] The method for manufacturing the secondary battery includes the step of, after overlapping the first electrode body and the second electrode body, inserting the first electrode body and the second electrode body into the case body from the first opening with the second current collector side as the leading end.

[0030] [3] The method for manufacturing a secondary battery according to [2], wherein:

[0031] The housing body has a second opening at an end portion opposite to the first opening.

[0032] The housing includes a second sealing plate for sealing the second opening.

[0033] The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode.

[0034] The method for manufacturing the secondary battery includes the step of electrically connecting the second current collector and the second electrode terminal after inserting the first electrode body and the second electrode body into the case body.

[0035] [4] The method for producing a secondary battery according to any one of [1] to [3], wherein:

[0036] The first electrode sheet and the third electrode sheet are bent in opposite directions such that the front end portions of the ends located on the side opposite to the side connected to the first electrode come close to each other.

[0037] [5] The method for producing a secondary battery according to any one of [1] to [3], wherein:

[0038] The first electrode sheet and the third electrode sheet are bent in the same direction such that the front end portions of the ends located on the side opposite to the side connected to the first electrode face the same direction.

[0039] [6] The method for producing a secondary battery according to any one of [1] to [5], wherein:

[0040] The second current collector is composed of a single component.

[0041] The present technology provides the following secondary batteries.

[0042] [7] A secondary battery, wherein:

[0043] The secondary battery has:

[0044] A first electrode body and a second electrode body, each of which includes a first electrode and a second electrode having a polarity different from that of the first electrode;

[0045] a housing that accommodates the first electrode body and the second electrode body; and

[0046] a first electrode terminal electrically connected to the first electrode,

[0047] The first electrode body includes a first electrode sheet disposed at a first end portion and electrically connected to the first electrode, and a second electrode sheet disposed at a second end portion and electrically connected to the second electrode.

[0048] The second electrode body includes a third electrode sheet disposed at a third end portion and electrically connected to the first electrode, and a fourth electrode sheet disposed at a fourth end portion and electrically connected to the second electrode.

[0049] The first electrode body and the second electrode body are arranged in a thickness direction of the first electrode body and the second electrode body,

[0050] The first electrode sheet is bonded to the first current collector.

[0051] The second electrode sheet and the fourth electrode sheet are bonded to the second current collector.

[0052] The third electrode sheet is bonded to the third current collector.

[0053] The first current collector and the third current collector are formed of separate components.

[0054] [8] The secondary battery according to [7], wherein:

[0055] The housing includes: a housing body having a first opening; and a first sealing plate for sealing the first opening.

[0056] The first sealing plate is provided with the first electrode terminal.

[0057] [9] The secondary battery according to [8], wherein

[0058] The housing body has a second opening at an end portion opposite to the first opening.

[0059] The housing includes a second sealing plate for sealing the second opening.

[0060] The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode.

[0061]

[10] The secondary battery according to any one of [7] to [9], wherein

[0062] The second electrode sheet and the fourth electrode sheet are bent in opposite directions such that the front end portions of the ends located on the side opposite to the side connected to the second electrode come close to each other.

[0063]

[11] The secondary battery according to any one of [7] to

[10] , wherein

[0064] The first electrode sheet and the third electrode sheet are bent in opposite directions such that the front end portions of the ends located on the side opposite to the side connected to the first electrode come close to each other.

[0065]

[12] The secondary battery according to any one of [7] to

[10] , wherein

[0066] The first electrode sheet and the third electrode sheet are bent in the same direction so that the front end portions of the ends located on the side opposite to the side connected to the first electrode face the same direction.

[0067]

[13] The secondary battery according to any one of [7] to

[12] , wherein

[0068] The second current collector is composed of a single component.

[0069] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a front view showing the structure of the secondary battery according to the first embodiment of the present technology.

[0071] Figure 2 It means observing from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0072] Figure 3 It means observing from the direction of arrow III Figure 1 A diagram showing the state of a secondary battery.

[0073] Figure 4 It means observing from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0074] Figure 5 It means when viewed from the direction of arrow V Figure 1 A diagram showing the state of a secondary battery.

[0075] Figure 6 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0076] Figure 7 It is a front view showing a negative electrode original plate before the negative electrode plate is formed.

[0077] Figure 8 yes Figure 7 VIII-VIII cross-sectional view of the negative electrode original plate shown.

[0078] Fig. 9 It is a front view showing a negative electrode plate formed from a negative electrode original plate.

[0079] Fig.10 It is a front view showing a positive electrode original plate before forming the positive electrode plate.

[0080] Fig.11 yes Fig.10 XI-XI cross-sectional view of the positive electrode original plate shown.

[0081] Fig.12 It is a front view showing a positive electrode plate formed from a positive electrode original plate.

[0082] Fig.13 yes Figure 1 XIII-XIII cross-sectional view of the secondary battery shown.

[0083] Fig.14 yes Figure 1 A XIV-XIV cross-sectional view of the secondary battery shown.

[0084] Fig.15 This is a flowchart showing the method for manufacturing the secondary battery according to the first embodiment.

[0085] Fig.16 It is a perspective view showing a state before two electrode bodies included in the secondary battery according to the first embodiment are overlapped.

[0086] Fig.17 yes Fig.16 XVII-XVII cross-sectional view of the electrode body and the current collector shown.

[0087] Fig.18 It is a perspective view showing a state where a holder and a separator are attached to an electrode body.

[0088] Fig.19 It is a perspective view showing a state where the first sealing plate is attached to the first current collector.

[0089] Fig. 20 yes Fig.19 XX-XX cross-sectional view of the electrode body and the current collector shown.

[0090] Fig.21 It is a perspective view showing a state where the electrode body is inserted into the case body.

[0091] Fig. 22 It is a perspective view showing a state where the second sealing plate is attached to the second current collector.

[0092] Fig.23 yes Fig. 22 XXIII-XXIII cross-sectional view of the electrode body and the current collector shown.

[0093] Fig.24 It is a perspective view showing the structure of the secondary battery according to the first embodiment.

[0094] Fig.25 It is a cross-sectional view showing the structure of a secondary battery according to the second embodiment.

[0095] Fig.26 It is a plan view showing a state before two electrode bodies included in the secondary battery according to the second embodiment are overlapped.

[0096] Fig. 27 It is a plan view showing a state before two electrode bodies included in the secondary battery according to the third embodiment are overlapped. DETAILED DESCRIPTION

[0097] Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals are given to the same or corresponding parts, and description thereof may not be repeated.

[0098] In addition, in the embodiments described below, when the number, amount, etc. are mentioned, the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, except for the cases where there are special records, each component is not necessarily essential to the present technology. In addition, the present technology is not necessarily limited to the technology that has all the effects mentioned in the present embodiment.

[0099] In addition, in this specification, the descriptions of "comprise", "include", and "have" are open forms. That is, when a certain structure is included, other structures other than the structure may or may not be included.

[0100] In addition, in this specification, when geometrical terms and terms indicating position and direction relationships are used, such as "parallel", "orthogonal", "oblique 45 degrees", "coaxial", "along", etc., these terms allow for manufacturing errors or some changes. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used to indicate relative positional relationships in one state, and the relative positional relationship can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0101] In this specification, "secondary battery" is not limited to lithium-ion batteries, and may include other secondary batteries such as nickel-hydrogen batteries and sodium-ion batteries. In this specification, "electrode" may be collectively referred to as positive electrode and negative electrode.

[0102] In addition, in the drawings, the direction along the winding axis of the electrode body of the secondary battery is set as the X direction, the short side direction of the electrode body when viewed from the X direction is set as the Y direction, and the long side direction of the electrode body when viewed from the X direction is set as the Z direction. In addition, in order to facilitate the understanding of the invention, there are parts in which the dimensions of each structure in the drawings are changed from the actual dimensions.

[0103] In the present application specification, there is the following situation, namely: the first direction (X direction) is referred to as the "width direction" of the secondary battery or the shell body, and the second direction (Y direction) is referred to as the "thickness direction" of the secondary battery or the shell body, and the third direction (Z direction) is referred to as the "height direction" of the secondary battery or the shell body.

[0104] (Implementation Method 1)

[0105] (Overall structure of the battery)

[0106] Figure 1 It is a front view of the secondary battery 1 according to the present embodiment. Figure 2 to Figure 5 They are respectively viewed from the direction of arrow II, arrow III, arrow IV, and arrow V. Figure 1 The diagram shows the state of the secondary battery 1. Figure 6 yes Figure 1 The secondary battery 1 is shown in front cross-sectional view.

[0107] The secondary battery 1 can be mounted on an electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), etc. However, the use of the secondary battery 1 is not limited to vehicle-mounted use.

[0108] like Figure 1 to Figure 6 As shown, the secondary battery 1 includes a case 100 , an electrode body 200 , an electrode terminal 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 .

[0109] When forming a battery pack including secondary batteries 1, a plurality of secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y direction) by a constraining member to form a battery module, or the battery pack may be directly supported by the side surface of the battery pack housing without using a constraining member.

[0110] The case body 110 is formed of a cylindrical, preferably rectangular, member. This provides 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.

[0111] like Figure 1 , Figure 2 As shown in FIG. 1 , a first sealing plate 120 and a second sealing plate 130 are provided at both ends of the housing body. The housing body 110 is formed by, for example, bringing the ends of the plate-like members subjected to bending into contact with each other (at Figure 2 The square tube shape can be formed by joining the two members (for example, laser welding) to each other as shown in the joining portion 115 illustrated in FIG. 1. The corners of the “square tube shape” may also have an R shape.

[0112] In the present embodiment, the shell body 110 is formed in the width direction (X direction) of the secondary battery 1 to be longer than the thickness direction (Y direction) and the height direction (Z direction) of the secondary battery 1. The dimension (width) of the shell body 110 in the X direction is preferably more than 30 cm. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension (height) of the shell body 110 in the Z direction is preferably less than 20 cm, more preferably less than 15 cm, and further preferably less than 10 cm. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved.

[0113] The housing body 110 includes a pair of first side portions 111 and a pair of second side portions 112. The pair of first side portions 111 constitute a portion of the side surface of the housing 100. The pair of second side portions 112 constitute the bottom surface portion and the upper surface portion of the housing 100. The pair of first side portions 111 and the pair of second side portions 112 are arranged to intersect each other. The pair of first side portions 111 and the pair of second side portions 112 are connected at their respective ends. The area of ​​each of the pair of first side portions 111 is preferably larger than the area of ​​each of the pair of second side portions 112.

[0114] like Figure 5 As shown, a second side surface 112A of one of the pair of second side surfaces 112 is provided with an exhaust valve 150. The exhaust valve 150 extends along the width direction (X direction) of the secondary battery 1. The exhaust valve 150 extends from the center of the housing body 110 in the X direction along the X direction to an extent that it does not reach both ends. The exhaust valve 150 can be appropriately changed.

[0115] The thickness of the plate-shaped member in the exhaust valve 150 is formed thinner than the thickness of the plate-shaped member of the housing body 110 other than the exhaust valve 150. Therefore, when the pressure in the housing 100 becomes equal to or higher than a predetermined value, the exhaust valve 150 breaks preferentially compared to other parts in the housing body 110, thereby exhausting the gas in the housing 100 to the outside.

[0116] like Figure 2 As shown, 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 along the width direction (X direction) of the secondary battery 1. In the joint portion 115, the edge sides of the plate-like members constituting the case body 110 are joined to each other.

[0117] like Figure 3 As shown, a first opening 113 is provided at the end of the first side in the first direction (X direction) of the housing body 110. The first opening 113 is sealed by a first sealing plate 120. A joint 115 is formed in the first opening 113 to seal the first opening 113. The first opening 113 and the first sealing plate 120 have a substantially rectangular shape with the Y direction as the short side direction and the Z direction as the long side direction.

[0118] 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.

[0119] like Figure 4 As shown, a second opening 114 is provided at the end of the second side on the side opposite to the first side in the first direction (X direction) of the housing body 110. That is, the second opening 114 is located at the end on the side opposite to the first opening 113. The second opening 114 is sealed by the second sealing plate 130. A joint 115 is formed in the second opening 114 to seal the second opening 114. The second opening 114 and the second sealing plate 130 have a substantially rectangular shape with the Y direction as the short side direction and the Z direction as the long side direction.

[0120] The second sealing plate 130 is provided with a positive electrode terminal 302 (second electrode terminal) and a liquid injection hole 134. The positions of the positive electrode terminal 302 and the liquid injection hole 134 can be changed as appropriate.

[0121] 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, iron alloy, or the like.

[0122] 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 , that is, to the case 100 .

[0123] The positive electrode terminal 302 is electrically connected to the positive electrode (second electrode) of the electrode body 200 . The positive electrode terminal 302 is attached to the second sealing plate 130 , that is, to the case 100 .

[0124] The negative electrode terminal 301 is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy, etc. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 301 .

[0125] The positive electrode terminal 302 is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy.

[0126] The liquid injection hole 134 is sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal member can be used.

[0127] The electrode body 200 is a flat electrode body having a positive electrode plate and a negative electrode plate described later. Specifically, the electrode body 200 is a wound electrode body formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate together via a strip-shaped separator not shown. However, in this specification, the "electrode body" is not limited to a wound electrode body, and may also be a stacked electrode body formed by alternately stacking a plurality of positive plates and a plurality of negative plates. The strip-shaped separator can be composed of a polyolefin microporous film, for example. The electrode body includes a plurality of positive plates and a plurality of negative plates, and the positive electrode sheets arranged on each positive plate may also be stacked to form a positive electrode sheet group, and the negative electrode sheets arranged on each negative plate may also be stacked to form a negative electrode sheet group. In addition, the electrode body 200 may include a plurality of wound electrode bodies, or may include a plurality of stacked electrode bodies.

[0128] like Figure 6 As shown, the housing 100 accommodates the electrode body 200. Figure 6 In the embodiment, a first electrode body 201 described later is exemplified. The first electrode body 201 is housed in the case 100 so that its winding axis is parallel to the X direction.

[0129] Specifically, a single or a plurality of wound electrode bodies and an electrolyte (electrolyte) not shown are housed inside an insulating sheet 700 (described later) disposed in the housing 100. As the electrolyte (non-aqueous electrolyte), for example, LiPF 20 dissolved in a non-aqueous solvent prepared by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) at a volume ratio (25° C.) of 30:30:40 can be used. 6 In addition, a solid electrolyte can also be used instead of the electrolyte.

[0130] The first electrode body 201 includes a main body (a portion where a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween), a first electrode sheet 220 (negative electrode sheet group), and a second electrode sheet 250 (positive electrode sheet group).

[0131] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240 described later. The first electrode sheet 220 is located at an end portion of the first electrode body 201 on the first side in the first direction (X direction) relative to the main body. The first side in this embodiment is the first sealing plate 120 side. The second electrode sheet 250 is located at an end portion of the second side of the first electrode body 201 in the first direction (X direction) relative to the main body. The second side in this embodiment is the second sealing plate 130 side.

[0132] The first electrode sheet 220 and the second electrode sheet 250 are formed so as to protrude from the central portion of the electrode body 200 toward the first sealing plate 120 or the second sealing plate 130 , respectively.

[0133] 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 formed of a plate-like member. The electrode body 200 is electrically connected to the negative electrode terminal 301 and the positive electrode terminal 302 via the current collector 400 .

[0134] The negative electrode current collector 400A is arranged on the first sealing plate 120 via an insulating member made of resin. The negative electrode current collector 400A is electrically connected to the first electrode sheet 220 and the negative electrode terminal 301. The negative electrode current collector 400A is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy. In addition, the details of the negative electrode current collector 400A will be described later.

[0135] The positive electrode collector 400B is arranged on the second sealing plate 130 via an insulating member made of resin. The positive electrode collector 400B is electrically connected to the second electrode sheet 250 and the positive terminal 302. The positive electrode collector 400B is composed of a conductive material (more specifically, a metal), for example, it can be composed of aluminum or an aluminum alloy. In addition, the second electrode sheet 250 can also be electrically connected to the second sealing plate 130 directly, or electrically connected to the second sealing plate 130 via the positive electrode collector 400B. In this case, the second sealing plate 130 can also play the role of the positive terminal 302. In addition, the details of the positive electrode collector 400B will be described later.

[0136] (Structure of Electrode Body 200)

[0137] Figure 7 2 is a front view showing a negative electrode original plate 210S before the negative electrode plate 210 (first electrode) is formed. Figure 8 yes Figure 7 The VIII-VIII cross-sectional view of the negative electrode original plate 210S shown in FIG. Fig. 9 1 is a front view showing a negative electrode plate 210 formed from a negative electrode original plate 210S.

[0138] The negative electrode plate 210 is manufactured by processing the negative electrode original plate 210S. Figure 7 and Figure 8 As shown, the negative electrode original plate 210S includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is a copper foil or a copper alloy foil.

[0139] The negative electrode core 211 has a negative electrode active material layer 212 formed thereon except for one end portion of both surfaces. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry using a die coater.

[0140] The negative electrode active material layer slurry is prepared by kneading graphite as a negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders, and water as a dispersion medium so that the mass ratio of graphite:SBR:CMC is about 98:1:1.

[0141] The negative electrode core 211 coated with the negative electrode active material layer slurry is dried and the water contained in the negative electrode active material layer slurry is removed to form the negative electrode active material layer 212. Furthermore, the negative electrode original plate 210S including the negative electrode core 211 and the negative electrode active material layer 212 is formed by compressing the negative electrode active material layer 212. The negative electrode original plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode original plate 210S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing.

[0142] like Fig. 9 As shown, at one end in the width direction of the negative electrode plate 210 formed by the negative electrode original plate 210S, a plurality of negative electrode sheets 230 formed by the negative electrode core 211 are provided. When the negative electrode plate 210 is wound, the plurality of negative electrode sheets 230 are stacked to form the first electrode sheet 220. Thus, the first electrode sheet 220 is connected to the negative electrode plate 210 (first electrode). The positions of the respective plurality of negative electrode sheets 230 and the lengths in the protruding direction are appropriately adjusted in consideration of the state in which the first electrode sheet 220 is connected to the negative electrode collector 400A. In addition, the shape of the negative electrode sheet 230 is not limited to Figure 8 The shape illustrated in .

[0143] Fig.10 2 is a front view showing a positive electrode original plate 240S before the positive electrode plate 240 (second electrode) is formed. Fig.11 yes Fig.10 The XI-XI cross-sectional view of the positive electrode original plate 240S shown in FIG. Fig.121 is a front view showing a positive electrode plate 240 formed from a positive electrode original plate 240S.

[0144] The positive electrode plate 240 as the second electrode has a different polarity from the negative electrode plate 210 as the first electrode. The positive electrode plate 240 is manufactured by processing a positive electrode original plate 240S. Fig.10 and Fig.11 As shown, the positive electrode original 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 an aluminum foil or an aluminum alloy foil.

[0145] The positive electrode core body 241 has a positive electrode active material layer 242 formed thereon except for one end portion of both surfaces. The positive electrode active material layer 242 is formed on the positive electrode core body 241 by applying a positive electrode active material layer slurry using a die coater.

[0146] The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binding material, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium in such a manner that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material becomes approximately 97.5:1:1.5.

[0147] The positive electrode protection layer 243 is in contact with the positive electrode core 241 and is formed at one end of the positive electrode active material layer 242 in the width direction. The positive electrode protection layer 243 is formed on the positive electrode core 241 by applying the positive electrode protection layer slurry using a die coater. The positive electrode protection layer 243 has a resistance greater than that of the positive electrode active material layer 242.

[0148] The positive electrode protective layer slurry was prepared by kneading alumina powder, a carbon material as a conductive material, PVdF as a binder, and NMP as a dispersion medium so that the mass ratio of alumina powder:carbon material:PVdF was about 83:3:14.

[0149] The positive electrode core 241 coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry is dried and the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry is removed to form the positive electrode active material layer 242 and the positive electrode protective layer 243. Furthermore, the positive electrode original plate 240S including the positive electrode core 241, the positive electrode active material layer 242 and the positive electrode protective layer 243 is formed by compressing the positive electrode active material layer 242. The positive electrode plate 240 is formed by cutting the positive electrode original plate 240S into a predetermined shape. The positive electrode original plate 240S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing.

[0150] like Fig.12 As shown, at one end portion in the width direction of the positive electrode plate 240 formed by the positive electrode original plate 240S, a plurality of positive electrode sheets 260 formed by the positive electrode core 241 are provided. When the positive electrode plate 240 is wound, the plurality of positive electrode sheets 260 are stacked to form the second electrode sheet 250. Thus, the second electrode sheet 250 is connected to the positive electrode plate 240 (the second electrode). The positions of the respective plurality of positive electrode sheets 260 and the lengths in the protruding direction are appropriately adjusted in consideration of the state in which the second electrode sheet 250 is connected to the positive electrode collector 400B. In addition, the shape of the positive electrode sheet 260 is not limited to Fig.12 The shape illustrated in .

[0151] The positive electrode protection layer 243 is provided at the root of each of the plurality of positive electrode sheets 260. The positive electrode protection layer 243 does not necessarily need to be provided at the root of the positive electrode sheet 260.

[0152] In a typical example, the thickness of the negative electrode sheet 230 (one sheet) is smaller than the thickness of the positive electrode sheet 260 (one sheet). In this case, the thickness of the first electrode sheet 220 is smaller than the thickness of the second electrode sheet 250 .

[0153] (Connection Structure of Electrode Body 200 and Current Collector 400)

[0154] Fig.13 yes Figure 1 The XIII-XIII cross-sectional view of the secondary battery shown. Fig.13 As shown, the electrode body 200 includes a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 include a first electrode (negative electrode) and a second electrode (positive electrode), respectively. Alternatively, the electrode body 200 may be composed of three or more electrode bodies.

[0155] The electrode body 200 is formed by overlapping a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 are arranged in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0156] The first electrode body 201 includes a first electrode sheet 220. A first end 205 of the first electrode sheet 220 in the X direction is electrically connected to the first electrode. The second electrode body 202 includes a third electrode sheet 270. A third end 207 of the third electrode sheet 270 in the X direction is electrically connected to the first electrode.

[0157] The first electrode sheet 220 has a bent portion 221 and a front end portion 222. The bent portion 221 is a portion of the first electrode sheet 220 bent on the side connected to the first electrode relative to the front end portion 222. The front end portion 222 is a portion of the first electrode sheet 220 located on the side opposite to the side connected to the first electrode.

[0158] The third electrode sheet 270 has a bent portion 271 and a front end portion 272. The bent portion 271 is a portion of the third electrode sheet 270 bent on the side connected to the first electrode relative to the front end portion 272. The front end portion 272 is a portion of the third electrode sheet 270 located on the side opposite to the side connected to the first electrode.

[0159] The first electrode sheet 220 and the third electrode sheet 270 are bent in opposite directions so that the front ends 222 and 272 approach each other. In the present embodiment, the front ends 222 and 272 are separated, but the present invention is not limited to this structure, and the front ends 222 and 272 may be in contact with each other.

[0160] The negative electrode current collector 400A electrically connects the negative electrode terminal 301 to the first electrode sheet 220 and the third electrode sheet 270. The negative electrode current collector 400A in this embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the first sealing plate 120.

[0161] The negative electrode current collector 400A includes a first current collector 410 , a third current collector 430 , and a first electrode terminal-side current collector 440 .

[0162] The first current collector 410 is a plate-shaped component. The first current collector 410 has a long side direction in the Z direction and a short side direction in the Y direction. The third current collector 430 is a plate-shaped component. The third current collector 430 has a long side direction in the Z direction and a short side direction in the Y direction. The first current collector 410 and the third current collector 430 are arranged side by side in the Y direction. In this way, the first current collector 410 and the third current collector 430 are composed of independent components.

[0163] The first electrode sheet 220 is joined to the first current collector 410 at a joining portion 411 described later. The third electrode sheet 270 is joined to the third current collector 430 at a joining portion 431 described later. The joining portions 411 and 431 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In the present embodiment, the first electrode sheet 220 and the first current collector 410, and the third electrode sheet 270 and the third current collector 430 are joined, for example, by ultrasonic bonding.

[0164] The first electrode terminal side current collector 440 is joined to the first current collector 410 and the third current collector 430 at a joining portion (not shown) located at an end portion in the Z direction. The first electrode terminal side current collector 440 is connected to the negative electrode terminal 301. The connection between the first electrode terminal side current collector 440 and the negative electrode terminal 301 can be formed by caulking and / or welding, for example.

[0165] The negative electrode terminal 301 is provided so as to be exposed outside the first sealing plate 120 and reach the first electrode terminal-side current collector 440 of the negative electrode current collector 400A provided on the inner surface side of the first sealing plate 120 . The negative electrode terminal 301 is connected to the first plate portion 303 .

[0166] The first plate portion 303 is located outside the first sealing plate 120. The first plate portion 303 is arranged along the first sealing plate 120. The first plate portion 303 has conductivity. The first plate portion 303 is arranged to ensure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to another adjacent secondary battery. The connection between the negative terminal 301 and the first plate portion 303 can be formed by, for example, laser welding or the like.

[0167] A first insulating member 510 is disposed between the first plate portion 303 and the first sealing plate 120 . A second insulating member 520 is disposed between the negative electrode terminal 301 and the first sealing plate 120 . A third insulating member 530 is disposed between the first electrode terminal-side current collector 440 and the first sealing plate 120 .

[0168] However, the negative electrode terminal 301 may be electrically connected to the first sealing plate 120 . In addition, the first sealing plate 120 may also function as the negative electrode terminal 301 .

[0169] The separator 600 is disposed between the first sealing plate 120 and the electrode body 200. The separator 600 is made of an insulating resin member. The separator 600 includes a first member 610 and a second member 620. The first member 610 and the second member 620 are engaged with each other at engaging portions (not shown) at both ends in the Z direction.

[0170] The first member 610 and the second member 620 protrude in the Y direction at the end portion on the electrode body 200 side in the X direction. Thus, the spacer 600 plays a guiding role so that the bent portions 221 and 271 are easily bent when being bent.

[0171] An insulating sheet 700 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110. The insulating sheet 700 can be made of resin, for example. More specifically, the material of the insulating sheet 700 is, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0172] Fig.14 yes Figure 1The XIV-XIV cross-sectional view of the secondary battery shown. Regarding the connection structure between the electrode body 200 and the collector 400 on the second electrode (positive electrode) side of the secondary battery 1 in this embodiment, the part corresponding to the first collector 410 and the third collector 430 on the first electrode (negative electrode) side is composed of a single component, which is different from the structure on the first electrode (negative electrode) side.

[0173] The first electrode body 201 includes a second electrode sheet 250. A second end 206 of the second electrode sheet 250 in the X direction is electrically connected to the second electrode. The second electrode body 202 includes a fourth electrode sheet 280. A fourth end 208 of the fourth electrode sheet 280 in the X direction is electrically connected to the second electrode.

[0174] The second electrode sheet 250 has a bent portion 251 and a front end portion 252. The bent portion 251 is a portion of the second electrode sheet 250 bent on the side connected to the second electrode relative to the front end portion 252. The front end portion 252 is a portion of the second electrode sheet 250 located on the side opposite to the side connected to the second electrode.

[0175] The fourth electrode sheet 280 has a bent portion 281 and a front end portion 282. The bent portion 281 is a portion of the fourth electrode sheet 280 bent on the side connected to the second electrode relative to the front end portion 282. The front end portion 282 is a portion of the fourth electrode sheet 280 located on the side opposite to the side connected to the second electrode.

[0176] The second electrode sheet 250 and the fourth electrode sheet 280 are bent in opposite directions so that the front ends 252 and 282 approach each other. In this embodiment, the front ends 252 and 282 are separated, but the present invention is not limited to this structure, and the front ends 252 and 282 may be in contact with each other.

[0177] The positive electrode current collector 400B electrically connects the positive electrode terminal 302 to the second electrode sheet 250 and the fourth electrode sheet 280. The positive electrode current collector 400B in this embodiment is connected to the positive electrode terminal 302 between the electrode body 200 and the second sealing plate 130.

[0178] The positive electrode current collector 400B includes a second current collector 420 and a second electrode terminal-side current collector 450 .

[0179] The second current collector 420 is a plate-shaped member. The second current collector 420 has a long side direction in the Z direction and a short side direction in the Y direction. The second current collector 420 is formed of a single integral member.

[0180] The second electrode sheet 250 and the fourth electrode sheet 280 are joined to the second current collector 420 composed of one component at a joining portion 421 described later. The joining portion 421 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In the present embodiment, the second electrode sheet 250 and the fourth electrode sheet 280 are joined to the second current collector 420, for example, by ultrasonic bonding.

[0181] The second electrode terminal side current collector 450 is joined to the second current collector 420 at a joining portion (not shown) located at an end portion in the Z direction. The second electrode terminal side current collector 450 is connected to the positive electrode terminal 302. The connection between the second electrode terminal side current collector 450 and the positive electrode terminal 302 can be formed by caulking and / or welding, for example.

[0182] The positive electrode terminal 302 is provided so as to be exposed outside the second sealing plate 130 and reach the second electrode terminal-side current collector 450 of the positive electrode current collector 400B provided on the inner surface side of the second sealing plate 130 . The positive electrode terminal 302 is connected to the second plate portion 304 .

[0183] The second plate portion 304 is located outside the second sealing plate 130. The second plate portion 304 is arranged along the second sealing plate 130. The second plate portion 304 has conductivity. The second plate portion 304 is arranged to ensure a connection area between the secondary battery 1 and an external terminal. The connection between the positive terminal 302 and the second plate portion 304 can be formed by, for example, laser welding.

[0184] A first insulating member 510 is disposed between the second plate portion 304 and the second sealing plate 130 . A second insulating member 520 is disposed between the positive electrode terminal 302 and the second sealing plate 130 . A third insulating member 530 is disposed between the second electrode terminal-side current collector 450 and the second sealing plate 130 .

[0185] However, the positive electrode terminal 302 may be electrically connected to the second sealing plate 130 . In addition, the second sealing plate 130 may also play the role of the positive electrode terminal 302 .

[0186] A separator 600 is disposed between the second sealing plate 130 and the electrode body 200. The separator 600 is made of an insulating resin member. The separator 600 includes a first member 610 and a second member 620. The first member 610 and the second member 620 are engaged with each other at engaging portions (not shown) at both ends in the Z direction.

[0187] The end portions of the first member 610 and the second member 620 on the electrode body 200 side in the X direction protrude in the Y direction. Thus, the spacer 600 plays a guiding role when the bent portions 251 and 281 are bent, so that the bent portions 251 and 281 are easily bent.

[0188] An insulating sheet 700 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110 .

[0189] (Manufacturing process of secondary battery 1)

[0190] Hereinafter, a method for manufacturing the secondary battery according to the present embodiment will be described. Fig.15 This is a flowchart showing the method for manufacturing the secondary battery according to the first embodiment. Fig.16 It is a perspective view showing a state before two electrode bodies included in the secondary battery according to the first embodiment are overlapped. Fig.17 yes Fig.16 XVII-XVII cross-sectional view of the electrode body and the current collector shown.

[0191] like Fig.15 As shown, in the manufacturing method of the secondary battery of the present embodiment, first, the first electrode body 201 and the second electrode body 202 are made (S1 process). For each of the first electrode sheet 220, the second electrode sheet 250, the third electrode sheet 270 and the fourth electrode sheet 280, a part of the front end is cut off so that the length of the front end becomes the same length when they are bundled.

[0192] like Figure 15 to Figure 17 As shown, after the first electrode body 201 and the second electrode body 202 are formed, the first electrode sheet 220 is joined to the first current collector 410 (S2 process). The first electrode sheet 220 is joined to the first current collector 410 at the joining portion 411. Next, the third electrode sheet 270 is joined to the third current collector 430 (S3 process). The third electrode sheet 270 is joined to the third current collector 430 at the joining portion 431.

[0193] Next, the first electrode body 201, the second current collector 420, and the second electrode body 202 are arranged in sequence in one direction (DR1 direction). The second electrode sheet 250 is arranged on one side of the second current collector 420 in one direction (DR1 direction). The second electrode sheet 250 and the fourth electrode sheet 280 are joined to the second current collector 420 in a state where the fourth electrode sheet 280 is arranged on the other side of the second current collector 420 in one direction (DR1 direction) (S4 process). The second electrode sheet 250 and the fourth electrode sheet 280 are joined to the second current collector 420 at the joining portion 421. As a result, the second electrode sheet 250 and the fourth electrode sheet 280 are electrically connected to the second current collector 420 when the first electrode body 201 is arranged on one side of the second current collector 420 and the second electrode body 202 is arranged on the other side of the second current collector 420 in one direction (DR1 direction). In addition, at this time, the second electrode sheet 250 and the fourth electrode sheet 280 may be connected to the second current collector 420 in an overlapping state.

[0194] like Fig.16 As shown, the second electrode sheet 250 and the fourth electrode sheet 280 are electrically connected to the second electrode body 202 in a state where the main body of the first electrode body 201 (the part where the positive electrode plate and the negative electrode plate are stacked with the separator) are separated from the main body of the second electrode body 202. When the second current collector 420 is viewed from above in this state, the main body of the first electrode body 201 does not overlap with the main body of the second electrode body 202. In addition, it is preferred that when the second current collector 420 is viewed from above, the main body of the first electrode body 201 and the main body of the second electrode body 202 are in a positional relationship that they do not overlap with the second current collector 420.

[0195] It is preferred that at least one of the second electrode sheet 250 and the fourth electrode sheet 280 be joined to the second current collector 420 while the first electrode body 201 and the second electrode body 202 are arranged in one direction (DR1 direction). In addition, the second electrode sheet 250 or the fourth electrode sheet 280 may be joined to the second current collector 420 in advance before the first electrode body 201 and the second electrode body 202 are arranged in one direction (DR1 direction). In addition, it is particularly preferred that the second current collector 420 is a metal component as in the present embodiment.

[0196] 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 and the third current collector 430 are arranged to one side from the center of the first electrode body 201 and the second electrode body 202. This allows the current collector to be shorter and smaller.

[0197] In addition, the first current collector 410, the second current collector 420, and the third current collector 430 are not limited to this structure. The first current collector 410, the second current collector 420, and the third current collector 430 may also be arranged at 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 sheet 220, the second electrode sheet 250, the third electrode sheet 270, and the fourth electrode sheet 280 are arranged at the center of the first electrode body 201 and the second electrode body 202, respectively, in accordance with the first current collector 410, the second current collector 420, and the third current collector 430.

[0198] In addition, the order of the process of joining the first current collector 410, the second current collector 420, and the third current collector 430 to the first electrode body 201 and the second electrode body 202, respectively, is not limited to the above case, and the order may be changed. The process of joining the first current collector 410 and the third current collector 430 to the first electrode body 201 and the second electrode body 202, respectively, is preferably performed before the process of overlapping the first electrode body 201 and the second electrode body 202 described later, and is preferably performed before the process of joining the second current collector 420 to the first electrode body 201 and the second electrode body 202.

[0199] Next, after the second electrode sheet 250 and the fourth electrode sheet 280 are bonded to the second current collector 420, the first electrode body 201 and the second electrode body 202 are bonded in the thickness direction (with respect to the thickness of the electrode sheet 250 and the fourth electrode sheet 280). Fig.16 and Fig.17 The second electrode sheet 250 and the fourth electrode sheet 280 are folded so that the first electrode sheet 220 and the third electrode sheet 270 are opposed to each other, and the first electrode body 201 and the second electrode body 202 are overlapped (step S5). That is, the first electrode body 201 and the second electrode body 202 are combined. In addition, at this moment, the first current collector 410 as a metal component and the second current collector 420 as a metal component are in a separated state as separate components.

[0200] By placing the second electrode sheet 250 and the fourth electrode sheet 280 toward Fig.17 The second electrode body 201 and the second electrode body 202 are bent in the direction of the arrow in the figure, and the second end 206 and the fourth end 208 are brought closer together compared to the state in the process of joining the second electrode sheet 250 and the fourth electrode sheet 280 to the second current collector 420. In addition, the first end 205 and the third end 207 are also brought closer together compared to the state in the process of joining the second electrode sheet 250 and the fourth electrode sheet 280 to the second current collector 420. Thus, the first electrode body 201 and the second electrode body 202 are overlapped.

[0201] “Overlapping the first electrode body with the second electrode body” may be performed by directly overlapping the first electrode body with the second electrode body, or other components may be arranged between the first electrode body and the second electrode body. In addition, the first electrode body and the second electrode body may be fixed by a tape or the like, or may not be fixed. Furthermore, the first electrode body, the second current collector, and the second electrode body may not be arranged on a straight line in one direction (DR1 direction), and the first electrode body or the second electrode body may be inclined in one direction (DR1 direction) relative to the second current collector.

[0202] The first electrode sheet 220 and the third electrode sheet 270 are placed Fig.17 Thus, the first electrode sheet 220 and the third electrode sheet 270 are configured so that the front ends thereof face each other.

[0203] Fig.18 1 is a perspective view showing a state where a retainer and a separator are installed on an electrode body. Fig.15 and Fig.18 As shown, the separator 600 and the insulating sheet 700 are then assembled to the electrode body 200 (step S6 ). Alternatively, after the separator 600 and the insulating sheet 700 are assembled to the electrode body 200 , the first electrode sheet 220 and the third electrode sheet 270 may be folded.

[0204] In addition, the insulating sheet 700 does not necessarily need to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers an area of ​​about 50% or more of the outer surface of the electrode body, and more preferably covers an area of ​​about 70% or more. The insulating sheet 700 preferably covers the entirety of four surfaces of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200, except for at least two surfaces on which the first electrode sheet 220 and the second electrode sheet 250 are formed.

[0205] Fig.19 It is a perspective view showing a state where the first sealing plate is attached to the first current collector. Fig. 20 yes Fig.19 XX-XX cross-sectional view of the electrode body and the current collector shown.

[0206] like Fig.15 , Fig.19 as well as Fig. 20 As shown, after the first electrode sheet 220 is bonded, the third electrode sheet 270 is bonded, and the first electrode body 201 and the second electrode body 202 are overlapped, the first current collector 410 and the third current collector 430 are electrically connected to the negative electrode terminal 301 (step S7).

[0207] In addition, the S7 step can be performed before the S6 step. By performing the S7 step before the S6 step, when the negative terminal 301 is electrically connected to the first electrode sheet 220 and the third electrode sheet 270, it is easy to more stably connect. In addition, the space between the first sealing plate 120 and the main body of the electrode body 200 is easy to be a smaller structure.

[0208] The first electrode sheet 220 and the third electrode sheet 270 are bent so that the front end portions 222 and 272 face each other.

[0209] The negative terminal 301 and the first electrode terminal side current collector 440 are mounted on the first sealing plate 120 via an insulating member. Thereafter, the first electrode terminal side current collector 440 is brought into contact with the first current collector 410 and the third current collector 430 from the X direction. The first electrode terminal side current collector 440 is joined to the first current collector 410 and the third current collector 430 by laser welding from between the first sealing plate 120 and the insulating sheet 700. In addition, the first plate portion 303 may be connected to the negative terminal 301 at any time.

[0210] Fig.21 2 is a perspective view showing a state where the electrode body is inserted into the shell body. Fig.15 and Fig.21 As shown, next, the first electrode body 201 and the second electrode body 202 that are stacked are inserted into the case body 110 from the first opening 113 with the second current collector 420 side as the leading end (step S8 ).

[0211] The first sealing plate 120 is brought into contact with the housing body 110. At this time, the first electrode sheet 220 and the third electrode sheet 270 are bent. Fig.13 As shown, the first electrode sheet 220 and the third electrode sheet 270 are bent along the shape of the separator 600 so that the folded-back portions of the bent portions 221 and 271 approach the case body 110 in the Y direction.

[0212] Thereafter, the first sealing plate 120 is preliminarily bonded to the case body 110. By the preliminarily bonding, the first sealing plate 120 is partially bonded to the first opening 113 of the case body 110. Thus, the first sealing plate 120 is positioned relative to the case body 110.

[0213] When the electrode body 200 is inserted into the case body 110, the electrode body 200 may be pulled from the second current collector 420 side, or may be pressed from the first current collector 410 and the third current collector 430 side. When the electrode body 200 is pressed from the first current collector 410 and the third current collector 430 side, the first electrode sheet 220 and the third electrode sheet 270 may be bent at the same time.

[0214] Fig. 22 It is a perspective view showing a state where the second sealing plate is attached to the second current collector. Fig.23 yes Fig. 22 XXIII-XXIII cross-sectional view of the electrode body and the current collector shown. Fig.23 , the housing body 110 is omitted.

[0215] like Fig.15 , Fig. 22 as well as Fig.23 As shown, next, after the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 , the second current collector 420 and the positive electrode terminal 302 are electrically connected (step S9 ).

[0216] Specifically, the positive terminal 302 and the second electrode terminal side current collector 450 are mounted on the second sealing plate 130 via an insulating member. The second electrode terminal side current collector 450 is brought into contact with the second current collector 420 from the X direction. The second electrode terminal side current collector 450 and the second current collector 420 are joined by laser welding from between the second sealing plate 130 and the insulating sheet 700. In addition, the second plate portion 304 may be connected to the positive terminal 302 at any time.

[0217] like Fig.23 As shown, the second electrode sheet 250 and the fourth electrode sheet 280 are bent so that the front end portions 252 and 282 face each other.

[0218] The second sealing plate 130 is brought into contact with the housing body 110. As a result, the second electrode sheet 250 and the fourth electrode sheet 280 are bent. Fig.14 As shown, the second electrode sheet 250 and the fourth electrode sheet 280 are bent along the shape of the separator 600 so that the folded-back portions of the bent portions 251 and 281 approach the case body 110 in the Y direction.

[0219] Thereafter, the second sealing plate 130 is preliminarily welded to the case body 110. By the preliminarily joining, the second sealing plate 130 is partially joined to the second opening 114 of the case body 110. Thus, the second sealing plate 130 is positioned relative to the case body 110.

[0220] Fig.24 1 is a perspective view showing the structure of a secondary battery according to Embodiment 1. Fig.15 and Fig.24As shown, next, the first sealing plate 120 and the second sealing plate 130 are joined to the housing body 110 (step S10). The first sealing plate 120 seals the first opening 113 of the housing body 110, and the second sealing plate 130 seals the second opening 114 of the housing body 110. Thus, the first electrode body 201 and the second electrode body 202 are accommodated in the housing 100.

[0221] After the above-mentioned process, a leakage check and other inspections are performed (S11 process). After the leakage check, the secondary battery 1 is dried to remove moisture in the shell 100. In addition, the electrolyte is injected into the interior of the shell 100 from the injection hole 134. When injecting the electrolyte, the second sealing plate 130 is at the top and the first sealing plate 120 is at the bottom to tilt the shell 100, and the electrolyte is injected into the interior of the shell 100 from the injection hole 134 of the second sealing plate 130. Thereafter, exhaust charging is performed. When performing exhaust charging, the injection hole 134 may also be pre-sealed. Thereafter, the injection hole is sealed to complete the secondary battery 1.

[0222] In the manufacturing method of the secondary battery 1 and the secondary battery 1 according to the first embodiment of the present technology, when the first electrode body 201 is arranged on one side of the second current collector 420 and the second electrode body 202 is arranged on the other side of the second current collector 420, the second electrode sheet 250 and the fourth electrode sheet 280 are electrically connected to the second current collector 420, and then the first electrode body 201 and the second electrode body 202 are overlapped. According to this structure, the electrode sheet can be shortened compared with the case where the first electrode body 201 and the second electrode body 202 form a single electrode sheet and the electrode sheet is bent. In addition, according to this structure, the length of each sheet can be shortened compared with the case where the second electrode sheet 250 and the fourth electrode sheet 280 in the overlapped first electrode body 201 and the second electrode body 202 are connected to the second current collector 420 respectively. As a result, the volume occupied by the electrode sheet can be reduced, so the energy density of the secondary battery 1 can be improved. In addition, the first electrode body 201 and the second electrode body 202 are each formed with an independent electrode sheet, and the electrode sheets are respectively bent to form the first electrode body 201 and the second electrode body 202. Compared with the case where the first electrode body 201 and the second electrode body 202 form an integral electrode sheet, the electrode sheet is easier to bend, so it is easier to join the electrode sheet with the collector, so that the secondary battery can be stably manufactured. In particular, by being able to stably manufacture the secondary battery 1, the reliability of the connection between the electrode sheet and the collector can be improved.

[0223] In the manufacturing method of the secondary battery 1 involved in embodiment 1 of the present technology, after the second electrode sheet 250 and the fourth electrode sheet 280 are joined together through the second current collector 420, the electrode body 200 can be easily inserted into the shell body 110 by inserting the first electrode body 201 and the second electrode body 202 from the side of the second current collector 420 that is joined to form a whole into the shell body 110.

[0224] In the manufacturing method of the secondary battery 1 and the secondary battery 1 according to the first embodiment of the present technology, the electrode body 200 can be applied to the case body 110 having the first opening 113 and the second opening 114 located at the end opposite to the first opening 113, and the electrode body 200 is configured such that: the first electrode body 201 and the second electrode body 202 are formed with independent electrode sheets, and the electrode sheets are bent to form the first electrode body 201 and the second electrode body 202. Thus, when the first opening 113 and the second opening 114 of the case body 110 are arranged in a horizontal direction, the secondary battery 1 can be made low-profile.

[0225] In the manufacturing method of the secondary battery 1 and the secondary battery 1 involved in embodiment 1 of the present technology, the first electrode sheet 220 and the third electrode sheet 270 are bent in opposite directions in such a manner that the front end portions 222 and 272 of the ends located on the side opposite to the side connected to the first electrode approach each other, thereby forming a structure that can easily shape the electrode sheet from the outside in the thickness direction of the electrode body.

[0226] In the manufacturing method of the secondary battery 1 and the secondary battery 1 involved in embodiment 1 of the present technology, compared with the case where separate current collectors are connected to the respective independent electrode sheets of the first electrode body 201 and the second electrode body 202, the electrode sheets can be connected by the second current collector 420 composed of an integrated component, thereby reducing the connection parts of the structural components and improving the reliability of the connection between the electrode sheets and the current collectors.

[0227] The following describes the secondary batteries according to Embodiment 2 and Embodiment 3. The secondary batteries according to these embodiments differ from the secondary battery 1 according to Embodiment 1 of the present technology in that the connection structure between the electrode body and the current collector is different, and therefore the same structure as the secondary battery 1 according to Embodiment 1 of the present technology will not be described repeatedly.

[0228] (Implementation Method 2)

[0229] Fig.25 It is a cross-sectional view showing the structure of a secondary battery according to the second embodiment. Fig.26 It is a plan view showing a state before two electrode bodies included in the secondary battery according to the second embodiment are overlapped.

[0230] like Fig.25 As shown, in the secondary battery according to the second embodiment, the front end portions 222A and 272A of the first electrode sheet 220A and the third electrode sheet 270A are bent in the same direction in the Y direction.

[0231] Thereafter, the first electrode body 201A and the second electrode body 202A are inserted into the housing body, and the first sealing plate 120 is brought into contact with the housing body. Thus, the first electrode sheet 220A and the third electrode sheet 270A are bent in the same direction in such a manner that the front end portions 222A and 272A located at the ends opposite to the side connected to the first electrode face the same direction. In order to facilitate bending of the front end portions 222A and 272A in the same direction, the third component 630A of the separator 600A is disposed between the first electrode sheet 220A and the third electrode sheet 270A.

[0232] When the front end portions 222A and 272A of the first electrode sheet 220A and the third electrode sheet 270A are bent in the same direction in the Y direction, the first electrode body 201A and the second electrode body 202A can be configured as one type of electrode body 200A.

[0233] Specifically, if Fig.26 As shown, before the first electrode body 201A and the second electrode body 202A are overlapped, and in a state where the first electrode body 201A and the second electrode body 202A are joined to the second current collector 420A, the first current collector 410A is arranged on one side (the DR1 direction) of the thickness direction of the electrode body 200A which is orthogonal to one direction (DR2 direction) relative to the first electrode sheet 220A. Fig.26 The third current collector 430A is bonded to the first electrode sheet 220A in a state of being on the back side of the paper in the figure. In addition, the third current collector 430A is arranged on the other side (the DR1 direction) of the thickness direction of the electrode body 200A which is orthogonal to one direction (DR2 direction) relative to the third electrode sheet 270A. Fig.26 It is joined to the third electrode sheet 270A in a state of being near the front side of the paper.

[0234] Before the first electrode body 201A and the second electrode body 202A are joined to the second current collector 420A, the positional relationship of the first current collector 410A relative to the first electrode sheet 220A and the positional relationship of the third current collector 430A relative to the third electrode sheet 270A are the same. Fig.26When the second electrode body 202A is observed in a top view in a manner that the third electrode sheet 270A is located on the left side relative to the center of the second electrode body 202A, the positional relationship of the first current collector 410A relative to the first electrode sheet 220A and the positional relationship of the third current collector 430A relative to the third electrode sheet 270A are arranged in the position of the current collector relative to the electrode sheet. Fig.26 Therefore, before the first electrode body 201A and the second electrode body 202A are joined to the second current collector 420A, the first electrode body 201A and the second electrode body 202A can be configured as one type of electrode body 200A.

[0235] After the first electrode body 201A and the second electrode body 202A are overlapped, Fig.25 As shown, the first current collector 410A and the third current collector 430A are bent so as to be arranged closer to the first sealing plate 120 than the first electrode sheet 220A and the third electrode sheet 270A, thereby bending the front end portions 222A and 272A in the same direction in the Y direction.

[0236] In the manufacturing method and the secondary battery of the secondary battery according to the second embodiment of the present technology, the first electrode sheet 220A and the third electrode sheet 270A are bent in the same direction in such a manner that the front end portions 222A and 272A of the first electrode sheet 220A and the third electrode sheet 270A face the same direction, thereby making it possible to make the positional relationship of the first current collector 410A relative to the first electrode sheet 220A and the positional relationship of the third current collector 430A relative to the third electrode sheet 270A the same positional relationship. Thus, the first electrode body 201A and the second electrode body 202 can be configured as one type of electrode body 200A, so that the electrode body 200A can be easily manufactured.

[0237] (Implementation 3)

[0238] Fig. 27 It is a plan view showing a state before two electrode bodies included in the secondary battery according to the third embodiment are overlapped.

[0239] like Fig. 27 As shown, the second current collector 420B included in the secondary battery according to Embodiment 3 may be composed of three members. Specifically, the second current collector 420B includes a first portion 425B, a second portion 426B, and a third portion 427B.

[0240] The first part 425B is joined to the second electrode sheet 250B, and the second part 426B is joined to the fourth electrode sheet 280B. Thereafter, in a state where the first electrode body 201B and the second electrode body 202B are arranged in one direction (DR1 direction), the first part 425B and the second part 426B are connected by the third part 427B, thereby forming an integrated second current collector 420B. The third part 427B is joined to the first part 425B and the second part 426B. The second current collector 420B is finally formed as one component.

[0241] Here, the first part 425B and the second part 426B are metal parts. The third part 427B can be a resin part, and the first part 425B and the second part 426B are held by the third part 427B. Thus, the second current collector 420B is integrated. In addition, as the above-mentioned holding method, fitting, bonding or welding can be considered. In addition, the third part 427B is not limited to a resin part.

[0242] In the manufacturing method and secondary battery of the secondary battery involved in the third embodiment of the present technology, when the first electrode body 201B is arranged on one side of the second current collector 420B and the second electrode body 202B is arranged on the other side of the second current collector 420B, the second electrode sheet 250B and the fourth electrode sheet 280B are electrically connected to the second current collector 420B, and then the first electrode body 201B and the second electrode body 202B are overlapped. With this structure, the electrode sheet can be shortened compared to the case where the first electrode body 201B and the second electrode body 202B form an integral electrode sheet and the electrode sheet is bent. In addition, with this structure, the length of each sheet can be shortened compared to the case where the second electrode sheet 250B and the fourth electrode sheet 280B in the overlapped first electrode body 201B and the second electrode body 202B are connected to the second current collector 420B respectively. As a result, the volume occupied by the electrode sheet can be reduced, thereby improving the energy density of the secondary battery. In addition, the first electrode body 201B and the second electrode body 202B form independent electrode sheets, and the electrode sheets are bent to form the first electrode body 201B and the second electrode body 202B. Compared with the case where the first electrode body 201B and the second electrode body 202B form an integral electrode sheet, the electrode sheet is easy to bend, so the electrode sheet can be easily joined to the collector, and the secondary battery can be stably manufactured. In particular, by being able to stably manufacture the secondary battery, the reliability of the connection between the electrode sheet and the collector can be improved.

[0243] The embodiments of the present invention have been described, but all points of the embodiments disclosed this time should be considered as illustrative and not limiting. The scope of the present invention is indicated by the claims, and is intended to include the meaning equivalent to the claims and all changes within the scope thereof.

Claims

1. A method for manufacturing a secondary battery, The secondary battery has: A first electrode body and a second electrode body, each of which includes a first electrode and a second electrode having a polarity different from that of the first electrode; a housing that accommodates the first electrode body and the second electrode body; and a first electrode terminal electrically connected to the first electrode, The first electrode body includes a first electrode sheet disposed at a first end portion and electrically connected to the first electrode, and a second electrode sheet disposed at a second end portion and electrically connected to the second electrode. The second electrode body includes a third electrode sheet disposed at a third end portion and electrically connected to the first electrode, and a fourth electrode sheet disposed at a fourth end portion and electrically connected to the second electrode. The first electrode sheet is bonded to the first current collector. The second electrode sheet and the fourth electrode sheet are bonded to the second current collector. The third electrode sheet is bonded to the third current collector. The first current collector and the third current collector are composed of independent components. The method for manufacturing the secondary battery is characterized by comprising the following steps: A step of manufacturing the first electrode body and the second electrode body; After the first electrode body and the second electrode body are manufactured, the first electrode sheet is joined to the first current collector; After the first electrode body and the second electrode body are manufactured, the third electrode sheet is joined to the third current collector; After the first electrode body and the second electrode body are manufactured, the second electrode sheet and the fourth electrode sheet are electrically connected to the second current collector in a state where the first electrode body is arranged on one side of the second current collector and the second electrode body is arranged on the other side of the second current collector; After the second electrode sheet and the fourth electrode sheet are bonded to the second current collector, the second electrode sheet and the fourth electrode sheet are bent to overlap the first electrode body and the second electrode body; as well as A step of electrically connecting the first current collector bonded to the first electrode sheet and the third current collector bonded to the third electrode sheet to the first electrode terminal after the first electrode body and the second electrode body are overlapped.

2. The method for manufacturing a secondary battery according to claim 1, characterized in that: The housing includes: a housing body having a first opening; and a first sealing plate that seals the first opening. The first sealing plate is provided with the first electrode terminal. The secondary battery manufacturing method includes the step of, after overlapping the first electrode body and the second electrode body, inserting the first electrode body and the second electrode body into the case body from the first opening with the second current collector side as the leading end.

3. The method for manufacturing a secondary battery according to claim 2, characterized in that: The housing body has a second opening at an end portion on the opposite side to the first opening. The housing includes a second sealing plate for sealing the second opening. The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode. The method for manufacturing a secondary battery includes the step of electrically connecting the second current collector and the second electrode terminal after inserting the first electrode body and the second electrode body into the case body.

4. The method for manufacturing a secondary battery according to any one of claims 1 to 3, characterized in that: The first electrode sheet and the third electrode sheet are bent in opposite directions such that the front end portions of the ends located on the side opposite to the side connected to the first electrode come close to each other.

5. The method for manufacturing a secondary battery according to any one of claims 1 to 3, characterized in that: The first electrode sheet and the third electrode sheet are bent in the same direction so that the front end portions of the ends located on the side opposite to the side connected to the first electrode face the same direction.

6. The method for manufacturing a secondary battery according to claim 1 or 2, characterized in that: The second current collector is composed of a single member.

7. A secondary battery, characterized in that: have: A first electrode body and a second electrode body, each of which includes a first electrode and a second electrode having a polarity different from that of the first electrode; a housing that accommodates the first electrode body and the second electrode body; and a first electrode terminal electrically connected to the first electrode, The first electrode body includes a first electrode sheet disposed at a first end portion and electrically connected to the first electrode, and a second electrode sheet disposed at a second end portion and electrically connected to the second electrode. The second electrode body includes a third electrode sheet disposed at a third end portion and electrically connected to the first electrode, and a fourth electrode sheet disposed at a fourth end portion and electrically connected to the second electrode. The first electrode body and the second electrode body are arranged in a thickness direction of the first electrode body and the second electrode body, The first electrode sheet is bonded to the first current collector. The second electrode sheet and the fourth electrode sheet are bonded to the second current collector. The third electrode sheet is bonded to the third current collector. The first current collector and the third current collector are formed of separate components.

8. The secondary battery according to claim 7, characterized in that: The housing includes: a housing body having a first opening; and a first sealing plate that seals the first opening. The first sealing plate is provided with the first electrode terminal.

9. The secondary battery according to claim 8, characterized in that: The housing body has a second opening at an end portion on the opposite side to the first opening. The housing includes a second sealing plate for sealing the second opening. The second sealing plate is provided with a second electrode terminal electrically connected to the second electrode.

10. The secondary battery according to any one of claims 7 to 9, characterized in that The second electrode sheet and the fourth electrode sheet are bent in opposite directions so that the front end portions of the ends located on the side opposite to the side connected to the second electrode come close to each other.

11. The secondary battery according to claim 7 or 8, characterized in that: The first electrode sheet and the third electrode sheet are bent in opposite directions so that the front end portions of the ends located on the side opposite to the side connected to the first electrode come close to each other.

12. The secondary battery according to claim 7 or 8, characterized in that: The first electrode sheet and the third electrode sheet are bent in the same direction so that the front end portions of the ends located on the side opposite to the side connected to the first electrode face the same direction.

13. The secondary battery according to claim 7 or 8, characterized in that: The second current collector is composed of a single member.

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