Secondary battery and manufacturing method thereof

Abstract

To provide a secondary battery of which the energy density is high and the reliability is improved as a result by avoiding the risk of damage of an electrode body when inserting the electrode body into a battery case and / or when assembling the case during liquid injection, and a manufacturing method thereof.SOLUTION: In a manufacturing method of a secondary battery, in a main body part of an electrode body, in an end at the side of a cathode tab 260, a cathode protective layer 243 protrudes closer to the cathode tab 260 than an end of an anode active material layer 212. In an end at the side of an anode tab, the anode active material layer protrudes closer to an anode tab 230 than an end of a cathode active material layer. A separator 800 includes a cathode side protrusion region 800x protruding closer to the cathode tab 260 than the end of the cathode protective layer 243 in an end at the side of the cathode tab 260 and includes an anode side protrusion region 800y protruding closer to the anode tab 230 than the end of the anode active material layer 212 in an end at the side of the anode tab 230. A protrusion length of the anode side protrusion region 800y is larger than a protrusion length of the cathode side protrusion region 800x.SELECTED DRAWING: Figure 25

Description

Technical Field

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

Background Art

[0002] U.S. Patent Publication No. 2022 / 0302533 (Patent Document 1) discloses a structure in which electrode tab groups are provided at both ends of an electrode body, and the electrode tab groups are connected to electrode terminals at both longitudinal ends of a battery case. By providing components for housing the electrode tab groups on both end sides of the battery case, the shape of the electrode tab groups is simplified, and an increase in the length of the current collection path is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When inserting the electrode body into the battery case and / or when standing the case during liquid injection, the electrode body (negative electrode active material layer existing at the corner) may be damaged. Furthermore, when inserting the electrode body into the battery case and / or when standing the case during liquid injection, the negative electrode end portion located at the lower end may come into contact via a spacer, a current collector, or the like and be damaged.

[0005] An object of the present technology is to be able to avoid the risk of damage to the electrode body when inserting the electrode body into the battery case and / or when standing the case during liquid injection, and as a result, to provide a secondary battery having a high energy density and high reliability and a method for manufacturing the same.

Means for Solving the Problems

[0006] The present technology provides the following secondary battery and a method for manufacturing the same.

[0007] [1] A secondary battery comprising: an electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator; and a case for housing the electrode body, wherein the case includes a case body having a first opening at one end and a second opening at the other end, a first sealing plate for sealing the first opening, and a second sealing plate for sealing the second opening. A first spacer is disposed between the first sealing plate and the electrode body, and a second spacer is disposed between the second sealing plate and the electrode body. The positive electrode plate has a positive electrode tab at an end on the second sealing plate side, and the negative electrode plate has a negative electrode tab at an end on the first sealing plate side. The positive electrode plate includes a positive electrode core, a positive electrode active material layer formed on the positive electrode core, and a positive electrode protection layer formed on the positive electrode core. In the positive electrode plate, the positive electrode protection layer is located on the positive electrode tab side with respect to the positive electrode active material layer. The negative electrode plate includes a negative electrode core and a negative electrode active material layer formed on the negative electrode core. The separator has a positive electrode side protruding region that protrudes on the positive electrode tab side with respect to the end of the positive electrode protection layer at the end on the positive electrode tab side, and a negative electrode side protruding region that protrudes on the negative electrode tab side with respect to the end of the negative electrode active material layer at the end on the negative electrode tab side. The separator has a region that is crushed by the first spacer in the negative electrode side protruding region.

[0008] [2] The separator has a region that is crushed by the second spacer in the positive electrode side protruding region, and the width of the crushed negative electrode side protruding region is larger than the width of the crushed positive electrode side protruding region. The secondary battery according to [1].

[0009] [3] The width of the negative electrode side protruding region of the separator is larger than the width of the positive electrode side protruding region. The secondary battery according to [1] or [2].

[0010] [4] The space volume from the end of the negative electrode active material layer to the first sealing plate is smaller than the space volume from the end of the positive electrode protection layer to the second sealing plate. The secondary battery according to any one of [1] to [3].

[0011] [5] A method for manufacturing a secondary battery, comprising: a step of manufacturing an electrode body in which a positive electrode plate and a negative electrode plate are laminated with a separator interposed therebetween; and a step of housing the electrode body in a case, wherein the case includes: a case body having a first opening at one end and a second opening at the other end; a first sealing plate for sealing the first opening; and a second sealing plate for sealing the second opening, the step of housing the electrode body in the case includes inserting the electrode body into the case body through the first opening, the electrode body has a main body portion, a positive electrode tab provided on the positive electrode plate and located on the second sealing plate side with respect to the main body portion, and a negative electrode tab provided on the negative electrode plate and located on the first sealing plate side with respect to the main body portion, the positive electrode plate includes a positive electrode core body, a positive electrode active material layer formed on the positive electrode core body, and a positive electrode protective layer formed on the positive electrode core body, in the positive electrode plate, the positive electrode protective layer is located on the positive electrode tab side with respect to the positive electrode active material layer, the negative electrode plate includes a negative electrode core body and a negative electrode active material layer formed on the negative electrode core body, in the main body portion of the electrode body, at the end on the positive electrode tab side, the positive electrode protective layer protrudes on the positive electrode tab side with respect to the end of the negative electrode active material layer, at the end on the negative electrode tab side, the negative electrode active material layer protrudes on the negative electrode tab side with respect to the end of the positive electrode active material layer, the separator has a positive electrode side protruding region that protrudes on the positive electrode tab side with respect to the end of the positive electrode protective layer at the end on the positive electrode tab side, and a negative electrode side protruding region that protrudes on the negative electrode tab side with respect to the end of the negative electrode active material layer at the end on the negative electrode tab side, and the protruding length of the negative electrode side protruding region is greater than the protruding length of the positive electrode side protruding region.

[0012] [6] The method for manufacturing a secondary battery according to [5], wherein the protruding length of the negative electrode side protruding region and the protruding length of the positive electrode side protruding region are both 2 mm or more.

[0013] [7] In the step of inserting the electrode body into the case body through the first opening, the step of inserting the electrode body into the case body from the first opening is included with a spacer disposed between the first sealing plate and the electrode body, and the negative electrode side protruding region is housed in the case body in such a manner that it is crushed in the region contacting the spacer. The method for manufacturing a secondary battery according to [5] or [6].

[0014] [8] Inserting the electrode body into the case body from the end of the electrode body where the positive electrode tab is disposed. The method for manufacturing a secondary battery according to any one of [5] to [7].

[0015] [9] After connecting the negative electrode tab and the first sealing plate, inserting the electrode body into the case body. The method for manufacturing a secondary battery according to [8].

[0016]

[10] After inserting the electrode body into the case body, connecting the positive electrode tab and the second sealing plate. The method for manufacturing a secondary battery according to [8].

[0017]

[11] Electrically connecting the negative electrode tab to the negative electrode terminal attached to the first sealing plate via a negative electrode current collector. The method for manufacturing a secondary battery according to any one of [5] to

[10] .

[0018]

[12] Electrically connecting the positive electrode tab to the positive electrode terminal attached to the second sealing plate via a positive electrode current collector. The method for manufacturing a secondary battery according to any one of [5] to

[10] .

Advantages of the Invention

[0019] According to the present technology, when inserting the electrode body into the battery case and / or when standing the case during liquid injection, it is possible to avoid the risk of damaging the electrode body. As a result, it is possible to provide a secondary battery having a high energy density and high reliability and a method for manufacturing the same.

Brief Description of the Drawings

[0020]

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Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals may be given to the same or corresponding parts, and the description thereof may not be repeated.

[0022] 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 that 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 limited to those that necessarily exhibit all the effects mentioned in this embodiment.

[0023] In addition, in this specification, the descriptions of "comprise", "include", and "have" are in an open-ended form. That is, when a certain configuration is included, other configurations other than the said configuration may or may not be included.

[0024] Also, in this specification, when geometric terms and terms representing positional and directional relationships, such as "parallel", "orthogonal", "45° oblique", "coaxial", "along", etc., are used, these terms allow for manufacturing errors or slight variations. When terms representing relative positional relationships such as "upper side" and "lower side" are used in this specification, these terms are used to indicate the relative positional relationship in one state, and depending on the installation direction of each mechanism (such as inverting the entire mechanism up and down, etc.), the relative positional relationship can be inverted or rotated at an arbitrary angle.

[0025] In this specification, the "secondary battery" is not limited to a lithium-ion battery and may include other secondary batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the "electrode" may be a general term for the positive electrode and the negative electrode.

[0026] Note that in the drawings, when the electrode body included in the secondary battery is a laminated electrode body, the longitudinal direction of the lamination plane is defined as the X direction, and when the electrode body is a wound electrode body, the direction along its winding axis is defined as the X direction. Also, the short-side direction of the electrode body as viewed from the X direction is defined as the Y direction, and the long-side direction of the electrode body as viewed from the X direction is defined as the Z direction. For ease of understanding of the invention, there are some places where the dimensions of each component in the drawings are shown as changed from the actual dimensions.

[0027] In this specification of the present application, the first direction (X direction) may be referred to as the "width direction" of the secondary battery or the case body, the second direction (Z direction) may be referred to as the "height direction" of the secondary battery or the case body, and the third direction (Y direction) may be referred to as the "thickness direction" of the secondary battery or the case body.

[0028] (Overall Configuration of the Battery) FIG. 1 is a front view of a secondary battery 1 according to one embodiment. FIGS. 2 to 5 are views showing the secondary battery 1 shown in FIG. 1 as viewed from the directions of arrow II, arrow III, arrow IV, and arrow V, respectively. FIG. 6 is a front cross-sectional view of the secondary battery 1 shown in FIG. 1.

[0029] The secondary battery 1 can be mounted on an electric vehicle (BEV: Battery Electric Vehicle), a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle), a hybrid vehicle (HEV: Hybrid Electric Vehicle), etc. However, the application of the secondary battery 1 is not limited to in-vehicle use.

[0030] As shown in FIGS. 1 to 6, 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 sealing plate 120 (first sealing plate), and a sealing plate 130 (second sealing plate).

[0031] When constructing a battery pack including the secondary battery 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 on the side surface of the case of the battery pack without using a constraining member.

[0032] The case body 110 is made of a cylindrical, preferably rectangular cylindrical member. Thereby, a rectangular secondary battery 1 can be obtained. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, an aluminum alloy, iron, or an iron alloy, etc.

[0033] As shown in FIGS. 1 and 2, a sealing plate 120 (first wall) and a sealing plate 130 (second wall) are respectively provided at both ends of the case body. The case body 110 can be formed into a rectangular tube shape, for example, by abutting the end edges of a plate-shaped member subjected to bending processing (joint portion 115 illustrated in FIG. 2) and joining them to each other (for example, laser welding). The corners of the "rectangular tube shape" may have an R shape. Further, the secondary battery in the present technology is not necessarily limited to a rectangular secondary battery.

[0034] In the present embodiment, the case body 110 is formed longer in the thickness direction (Y direction) and the height direction (Z direction) of the secondary battery 1 than in the width direction (X direction) of the secondary battery 1. The dimension (width) of the case body 110 in the X direction is preferably about 30 cm or more. Thereby, a relatively large (high-capacity) secondary battery 1 can be configured. The dimension (height) of the case body 110 in the Z direction is preferably about 20 cm or less, more preferably about 15 cm or less, and even more preferably about 10 cm or less. Thereby, a secondary battery 1 with a relatively low height (low height) can be configured, and for example, the mountability on a vehicle is improved.

[0035] The case body 110 includes a pair of first side surfaces 111 and a pair of second side surfaces 112. The pair of first side surfaces 111 constitute a part of the side surface of the case 100. The pair of second side surfaces 112 constitute the bottom surface portion and the top surface portion of the case 100. Each of the pair of first side surfaces 111 and the pair of second side surfaces 112 is provided so as to intersect each other. The pair of first side surfaces 111 and the pair of second side surfaces 112 are connected at their respective ends. It is desirable that the area of each of the pair of first side surfaces 111 is larger than that of each of the pair of second side surfaces 112.

[0036] As shown in FIG. 5, a gas discharge valve 150 is provided in one of the pair of second side portions 112, i.e., the second side portion 112A. The gas discharge valve 150 extends in the width direction (X direction) of the secondary battery 1. The gas discharge valve 150 extends in the X direction to such an extent that it does not reach both ends from the center of the case body 110 in the X direction. The gas discharge valve 150 can be appropriately changed.

[0037] The thickness of the plate-like member in the gas discharge valve 150 is thinner compared to the thickness of the plate-like members of the case body 110 other than the gas discharge valve 150. Thereby, when the pressure inside the case 100 becomes a predetermined value or more, the gas discharge valve 150 breaks preferentially compared to other portions of the case body 110, and discharges the gas inside the case 100 to the outside.

[0038] As shown in FIG. 2, a joint portion 115 is formed in the other second side portion 112B of the pair of second side portions 112. The joint portion 115 extends in the width direction (X direction) of the secondary battery 1. At the joint portion 115, the end edges of the plate-like members constituting the case body 110 are joined together.

[0039] As shown in FIG. 3, an opening 113 (first opening) is provided at the end of the case body 110 on the first side in the first direction (X direction). The opening 113 is sealed by a sealing plate 120. A joint portion 115 is formed in the opening 113, and the opening 113 is sealed. The opening 113 and the sealing plate 120 have a substantially rectangular shape in which the Y direction is the short side direction and the Z direction is the long side direction. Note that the substantially rectangular shape includes a rectangular shape, or a substantially rectangular shape such as a rectangular shape with R-rounded corners.

[0040] A negative electrode terminal 301 is provided on the sealing plate 120 (first sealing plate). The position of the negative electrode terminal 301 can be appropriately changed.

[0041] As shown in FIG. 4, an opening 114 (second opening) is provided at an end of the second side opposite to the first side of the case body 110 in the first direction (X direction). That is, the opening 114 is located at an end opposite to the opening 113, and the openings 113 and 114 face each other. The opening 114 is sealed by a sealing plate 130. A joint portion 115 is formed in the opening 114 to seal the opening 114. The opening 114 and the sealing plate 130 have a substantially rectangular shape in which the Y direction is the short side direction and the Z direction is the long side direction.

[0042] On the sealing plate 130 (second sealing plate), a positive electrode terminal 302 and a liquid injection hole 134 are provided. The positions of the positive electrode terminal 302 and the liquid injection hole 134 can be changed as appropriate.

[0043] The sealing plate 120 and the sealing plate 130 are made of metal. Specifically, the sealing plate 120 and the sealing plate 130 are made of aluminum, an aluminum alloy, iron, or an iron alloy.

[0044] The negative electrode terminal 301 (first electrode terminal) is electrically connected to the negative electrode of the electrode body 200. The negative electrode terminal 301 is attached to the sealing plate 120, that is, the case 100.

[0045] The positive electrode terminal 302 (second electrode terminal) is electrically connected to the positive electrode of the electrode body 200. The positive electrode terminal 302 is attached to the sealing plate 130, that is, the case 100.

[0046] The negative electrode terminal 301 is made of a conductive material (more specifically, metal), and can be made of, for example, copper or a copper alloy. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface portion of the negative electrode terminal 301.

[0047] The positive electrode terminal 302 is made of a conductive material (more specifically, metal), and can be made of, for example, aluminum or an aluminum alloy.

[0048] The liquid injection hole 134 is sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet and other metal members can be used.

[0049] The electrode body 200 is a flat-shaped electrode body in which a positive electrode plate and a negative electrode plate described later are laminated. Specifically, the electrode body 200 is a laminated electrode body (see FIG. 29 described later) in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately laminated via a separator 800 described later. However, in this specification, the "electrode body" is not limited to a laminated electrode body, and may be a wound electrode body (see FIG. 31 described later) in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are both wound via a strip-shaped separator. The separator can be constituted by, for example, a polyolefin microporous membrane. When the electrode body is a laminated electrode body including a plurality of positive electrode plates and a plurality of negative electrode plates, the positive electrode tabs provided on each positive electrode plate are laminated to form a positive electrode tab group, and the negative electrode tabs provided on each negative electrode plate are laminated to form a negative electrode tab group.

[0050] As shown in FIG. 6, the case 100 houses the electrode body 200. In FIG. 6, the first electrode body 201 described later is illustrated. The first electrode body 201 is housed in the case 100 such that its longitudinal direction is parallel to the X direction.

[0051] Specifically, inside the insulating sheet 700 described later disposed in the case 100, one or more laminated electrode bodies are housed together with an electrolytic solution (electrolyte) not shown. As the electrolytic solution (non-aqueous electrolytic solution), for example, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) are mixed in a volume ratio (25 ° C) of 30:30:40 in a non-aqueous solvent, and LiPF 6 dissolved at a concentration of 1.2 mol / L can be used. Note that a solid electrolyte may be used instead of the electrolytic solution.

[0052] The first electrode body 201 includes a substantially rectangular main body portion, a negative electrode tab group 220 (first electrode tab group), and a positive electrode tab group 250 (second electrode tab group).

[0053] The main body portion is composed of a negative electrode plate 210 and a positive electrode plate 240, which will be described later. The negative tab group 220 is located at the end of the first electrode body 201 on the first side in the first direction (X direction) with respect to the main body portion. In the present embodiment, the first side is the side of the sealing plate 120. The positive tab group 250 is located at the end of the first electrode body 201 on the second side in the first direction (X direction) with respect to the main body portion. In the present embodiment, the second side is the side of the sealing plate 130.

[0054] The negative tab group 220 and the positive tab group 250 are formed so as to protrude from the central portion of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0055] The current collector 400 includes a negative current collector 400A and a positive current collector 400B. The negative current collector 400A and the positive current collector 400B are each made of a plate-shaped member. The electrode body 200 is electrically connected to the negative terminal 301 and the positive terminal 302 via the current collector 400.

[0056] The negative current collector 400A is disposed on the sealing plate 120 via a resin insulating member. The negative current collector 400A is electrically connected to the negative tab group 220 and the negative terminal 301. The negative current collector 400A is made of a conductive material (more specifically, a metal) and can be made of, for example, copper or a copper alloy. Details of the negative current collector 400A will be described later.

[0057] The positive current collector 400B is disposed on the sealing plate 130 via a resin insulating member. The positive current collector 400B is electrically connected to the positive tab group 250 and the positive terminal 302. The positive current collector 400B is made of a conductive material (more specifically, a metal) and can be made of, for example, aluminum or an aluminum alloy. Note that the positive tab group 250 may be electrically connected to the sealing plate 130 directly or via the positive current collector 400B. In this case, the sealing plate 130 may serve as the positive terminal 302. Details of the positive current collector 400B will be described later.

[0058] (Configuration of the electrode body 200) FIG. 7 is a cross-sectional view of the negative electrode plate 210 (VII-VII cross-sectional view in FIG. 8), and FIG. 8 is a front view showing the negative electrode plate 210.

[0059] As shown in FIG. 8, a plurality of negative electrode tabs 230 (first electrode tabs) made of a negative electrode core 211 are provided at one end in the width direction of the negative electrode plate 210. When the negative electrode plates 210 are stacked, the plurality of negative electrode tabs 230 are stacked to form a negative electrode tab group 220. The length of each of the negative electrode tabs 230 in the protruding direction in the plurality of negative electrode plates 210 is appropriately adjusted in consideration of the state in which the negative electrode tab group 220 is connected to the negative electrode current collector 400A. Note that the shape of the negative electrode tab 230 is not limited to that illustrated in FIG. 7.

[0060] FIG. 9 is a cross-sectional view of the positive electrode plate 240 (IX-IX cross-sectional view in FIG. 10), and FIG. 10 is a front view showing the positive electrode plate 240.

[0061] As shown in FIG. 10, a plurality of positive electrode tabs 260 (second electrode tabs) made of a positive electrode core 241 are provided at one end in the width direction of the formed positive electrode plate 240. When the positive electrode plates 240 are stacked, the plurality of positive electrode tabs 260 are stacked to form a positive electrode tab group 250. The length of each of the positive electrode tabs 260 in the protruding direction in the plurality of positive electrode plates 240 is appropriately adjusted in consideration of the state in which the positive electrode tab group 250 is connected to the positive electrode current collector 400B. Note that the shape of the positive electrode tab 260 is not limited to that illustrated in FIG. 10.

[0062] A positive electrode protective layer 243 is provided at the base of the positive electrode tab 260. The positive electrode protective layer 243 does not necessarily have to be provided at the base of the positive electrode tab 260.

[0063] In a typical example, the thickness of one negative electrode tab 230 is smaller than the thickness of one positive electrode tab 260. In this case, the thickness of the negative electrode tab group 220 is smaller than the thickness of the positive electrode tab group 250.

[0064] (Connection structure between the electrode body 200 and the current collector 400) FIG. 11 is a cross-sectional view taken along line XI-XI of the secondary battery shown in FIG. 1. As shown in FIG. 11, the electrode body 200 includes a first electrode body 201 and a second electrode body 202. Each of the first electrode body 201 and the second electrode body 202 includes a positive electrode (second electrode) and a negative electrode (first electrode). Note that the electrode body 200 may be composed of three or more electrode bodies.

[0065] The electrode body 200 is formed by overlapping the first electrode body 201 and the second electrode body 202. The first electrode body 201 and the second electrode body 202 are arranged side by side in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0066] The first electrode body 201 includes a negative electrode tab group 220. The negative electrode tab group 220 is electrically connected to a current collector 410 (negative electrode current collector) at a first end portion 205 in the X direction. The second electrode body 202 includes a negative electrode tab group 270. The negative electrode tab group 270 is electrically connected to a current collector 430 (negative electrode current collector) at a third end portion 207 in the X direction.

[0067] The negative electrode tab group 220 has a curved portion 221 and a tip portion 222. The curved portion 221 is a portion where the negative electrode tab group 220 is curved on the side to which the first electrode is connected with respect to the tip portion 222. The tip portion 222 is a portion located at an end portion on the side opposite to the side to which the first electrode of the negative electrode tab group 220 is connected.

[0068] The negative electrode tab group 270 has a curved portion 271 and a tip portion 272. The curved portion 271 is a portion where the negative electrode tab group 270 is curved on the side to which the first electrode is connected with respect to the tip portion 272. The tip portion 272 is a portion located at an end portion on the side opposite to the side to which the first electrode of the negative electrode tab group 270 is connected.

[0069] Each of the negative electrode tab groups 220 and 270 is curved in opposite directions such that the tip portions 222, 272 approach each other. In the present embodiment, the tip portions 222, 272 are separated from each other, but the present invention is not limited to this configuration, and the tip portions 222, 272 may be in contact with each other.

[0070] The negative electrode current collector 400A electrically connects the negative electrode terminal 301 to the negative electrode tab group 220 and the negative electrode tab group 270. The negative electrode current collector 400A in the present embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the sealing plate 120.

[0071] The negative electrode current collector 400A includes a current collector 410 and a current collector 430 (third current collecting member) and a current collector 440 (fourth current collecting member).

[0072] The current collector 410 is a plate-like member. The current collector 410 has a longitudinal direction in the Z direction and a short side direction in the Y direction. The current collector 430 is a plate-like member. The current collector 430 has a longitudinal direction in the Z direction and a short side direction in the Y direction. The current collector 410 and the current collector 430 are arranged in parallel in the X direction. Thus, the current collector 410 and the current collector 430 are constituted by separate parts.

[0073] The negative electrode tab group 220 is joined to the current collector 410 at a joining portion 411 described later. The negative electrode tab group 270 is joined to the current collector 430 at a joining portion 431 described later. The joining portions 411, 431 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, caulking, or the like. In the present embodiment, the negative electrode tab group 220 and the current collector 410, and the negative electrode tab group 270 and the current collector 430 are joined by, for example, ultrasonic joining.

[0074] The current collector 440 is joined to the current collector 410 and the current collector 430 at a joining portion (not shown) located at an end portion in the Z direction. The current collector 440 is connected to the negative electrode terminal 301. The connection between the current collector 440 and the negative electrode terminal 301 can be formed by, for example, caulking and / or welding.

[0075] The negative electrode terminal 301 is provided so as to be exposed outside the sealing plate 120 and reach the current collector 440 of the negative electrode current collector 400A provided on the inner surface side of the sealing plate 120. The negative electrode terminal 301 is connected to the plate-like member 303.

[0076] The plate-like member 303 is located outside the sealing plate 120. The plate-like member 303 is arranged along the sealing plate 120. The plate-like member 303 has conductivity. The plate-like member 303 is arranged to secure 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 electrode terminal 301 and the plate-like member 303 can be formed by, for example, laser welding.

[0077] An insulating member 510 is arranged between the plate-like member 303 and the sealing plate 120. An insulating member 520 is arranged between the negative electrode terminal 301 and the sealing plate 120. An insulating member 530 is arranged between the current collector 440 and the sealing plate 120.

[0078] However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120. Also, the sealing plate 120 may serve as the negative electrode terminal 301.

[0079] A spacer 600 (first spacer), which will be described later, is arranged between the sealing plate 120 and the main body portion of the electrode body 200 (not including the negative electrode tab group 220). The spacer 600 is composed of an insulating resin member.

[0080] Although the detailed structure of the spacer 600 will be described later, the spacer 600 is provided with a convex portion 616 protruding in the Y direction. The convex portion 616 of this spacer 600 serves as a guide so that the bending portions 221, 271 are easily bent when the bending portions 221, 271 are bent.

[0081] An insulating sheet 700 (electrode body holder) made of resin is disposed between the electrode body 200 and the case body 110. The insulating sheet 700 can be constituted by, for example, resin. 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).

[0082] FIG. 12 is a cross-sectional view taken along the line XII-XII of the secondary battery shown in FIG. 1. The connection structure between the electrode body 200 and the current collector 400 on the positive electrode side of the secondary battery 1 in the present embodiment is different from the configuration on the negative electrode side in that portions corresponding to the current collectors 410 and 430 on the negative electrode side are constituted by a single component.

[0083] The first electrode body 201 includes a positive electrode tab group 250. The positive electrode tab group 250 is electrically connected to a current collector 420 (positive electrode current collector) at a second end portion 206 in the X direction. The second electrode body 202 includes a positive electrode tab group 280. The positive electrode tab group 280 is electrically connected to a current collector 420 (positive electrode current collector) at a fourth end portion 208 in the X direction.

[0084] The positive electrode tab group 250 has a curved portion 251 and a tip portion 252. The curved portion 251 is a portion where the positive electrode tab group 250 is curved on the side to which the second electrode is connected with respect to the tip portion 252. The tip portion 252 is a portion located at an end portion on the side opposite to the side to which the second electrode of the positive electrode tab group 250 is connected.

[0085] The positive electrode tab group 280 has a curved portion 281 and a tip portion 282. The curved portion 281 is a portion where the positive electrode tab group 280 is curved on the side to which the second electrode is connected with respect to the tip portion 282. The tip portion 282 is a portion located at an end portion on the side opposite to the side to which the second electrode of the positive electrode tab group 280 is connected.

[0086] Each of the positive electrode tab groups 250 and 280 is curved in opposite directions such that the tip portions 252 and 282 approach each other. In the present embodiment, the tip portions 252 and 272 are separated from each other, but the present invention is not limited to this configuration, and the tip portions 252 and 282 may be in contact with each other.

[0087] The positive electrode current collector 400B electrically connects the positive electrode terminal 302 to the positive electrode tab group 250 and the positive electrode tab group 280. The positive electrode current collector 400B in the present embodiment is connected to the positive electrode terminal 302 between the electrode body 200 and the sealing plate 130.

[0088] The positive electrode current collector 400B includes a current collector 420 (first current collecting member) and a current collector 450 (second current collecting member).

[0089] The current collector 420 is a plate-like member. The current collector 420 has a longitudinal direction in the Z direction and a short-side direction in the Y direction. The current collector 420 is formed of a single integrated part.

[0090] The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 which is formed of a single part at a joining portion 421 described later. The joining portion 421 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, caulking, or the like. In the present embodiment, the positive electrode tab group 250, the positive electrode tab group 280, and the current collector 420 are joined by, for example, ultrasonic joining.

[0091] The current collector 450 is joined to the current collector 420 at a joining portion (not shown) located at the end in the Z direction. The current collector 450 is connected to the positive electrode terminal 302. The connection between the current collector 450 and the positive electrode terminal 302 can be formed, for example, by caulking and / or welding.

[0092] The positive electrode terminal 302 is provided so as to be exposed outside the sealing plate 130 and reach the current collector 450 of the positive electrode current collector 400B provided on the inner surface side of the sealing plate 130. The positive electrode terminal 302 is connected to a plate-like member 304.

[0093] The plate-like member 304 is located outside the sealing plate 130. The plate-like member 304 is arranged along the sealing plate 130. The plate-like member 304 has conductivity. The plate-like member 304 is arranged to secure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the positive electrode terminal 302 and the plate-like member 304 can be formed, for example, by laser welding.

[0094] An insulating member 510 is arranged between the plate-like member 304 and the sealing plate 130. An insulating member 520 is arranged between the positive electrode terminal 302 and the sealing plate 130. An insulating member 530 is arranged between the current collector 450 and the sealing plate 130.

[0095] However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130. Also, the sealing plate 130 may serve as the positive electrode terminal 302.

[0096] A spacer 600 (second spacer) is arranged between the sealing plate 130 and the main body portion of the electrode body 200 (not including the positive electrode tab groups 250 and 280). The spacer 600 is composed of an insulating resin member.

[0097] Although the detailed structure of the spacer 600 will be described later, the spacer 600 is provided with a convex portion 616 protruding in the Y direction. The convex portion 616 of the spacer 600 serves as a guide so that the bending portions 251 and 281 are easily bent when the bending portions 251 and 281 are bent.

[0098] An insulating sheet 700 (electrode body holder) made of the above-described resin is arranged between the electrode body 200 and the case main body 110.

[0099] (Manufacturing process of the secondary battery 1) Hereinafter, a method for manufacturing a secondary battery according to the present embodiment will be described. FIG. 13 is a flowchart showing a method for manufacturing a secondary battery according to Embodiment 1. FIG. 14 is a perspective view showing a state before two electrode bodies included in the secondary battery according to Embodiment 1 overlap. FIG. 15 is a cross-sectional view taken along line XV-XV of the electrode body and the current collector shown in FIG. 14.

[0100] As shown in FIG. 13, in the method for manufacturing a secondary battery according to the present embodiment, first, a first electrode body 201 and a second electrode body 202 are produced (step S1). Each of the negative electrode tab group 220, the positive electrode tab group 250, the negative electrode tab group 270, and the positive electrode tab group 280 has a part of its tip cut so that the lengths of the tips are the same when bundled.

[0101] As shown in FIGS. 13 to 15, after the first electrode body 201 and the second electrode body 202 are produced, the negative electrode tab group 220 is joined to the current collector 410 (step S2). The negative electrode tab group 220 is joined to the current collector 410 at the joining portion 411. Next, the negative electrode tab group 270 is joined to the current collector 430 (step S3). The negative electrode tab group 270 is joined to the current collector 430 at the joining portion 431.

[0102] Next, the first electrode body 201, the current collector 420, and the second electrode body 202 are arranged side by side in this order in the first direction (DR1 direction). The positive electrode tab group 250 is arranged on one side of the current collector 420 in the first direction (DR1 direction). With the positive electrode tab group 280 arranged on the other side of the current collector 420 in the first direction (DR1 direction), the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 (step S4). The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 at the joining portion 421.

[0103] In the height direction of the first electrode body 201 and the second electrode body 202, the current collectors 410, 420, and 430 are arranged offset to one side from the center of the first electrode body 201 and the second electrode body 202. As a result, the current collector can be configured to be short, so that the current collector can be made small.

[0104] Note that the current collectors 410, 420, and 430 are not limited to this configuration. The current collectors 410, 420, and 430 may be disposed at the centers 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, each of the negative tab group 220, the positive tab group 250, the negative tab group 270, and the positive tab group 280 is disposed at the center of the first electrode body 201 and the second electrode body 202 in accordance with the current collectors 410, 420, and 430.

[0105] Also, the order of the steps of joining each of the current collectors 410, 420, and 430 to the first electrode body 201 and the second electrode body 202 is not limited to the above, and the order may be changed. The steps of joining each of the current collectors 410 and 430 to the first electrode body 201 and the second electrode body 202 are preferably performed before the step of overlapping the first electrode body 201 and the second electrode body 202 described later, and are preferably performed before the step of joining the current collector 420 to the first electrode body 201 and the second electrode body 202.

[0106] Next, after joining the positive tab group 250 and the positive tab group 280 to the current collector 420, in the thickness direction of the first electrode body 201 and the second electrode body 202 (the direction orthogonal to the DR1 direction in FIGS. 14 and 15), the positive tab group 250 and the positive tab group 280 are bent to overlap the first electrode body 201 and the second electrode body 202 (step S5). That is, the first electrode body 201 and the second electrode body 202 are put together.

[0107] "Stacking the first electrode body and the second electrode body" means that the first electrode body and the second electrode body may be directly stacked, or other members may be arranged between the first electrode body and the second electrode body. Also, the first electrode body and the second electrode body may or may not be fixed by a tape or the like. Furthermore, the first electrode body, the current collector, and the second electrode body do not have to be linearly arranged in the first direction (DR1 direction), and the first electrode body or the second electrode body may be inclined with respect to the current collector in the first direction (DR1 direction).

[0108] The positive electrode tab groups 250 and 280 are bent so that their tip portions face each other. Also, the negative electrode tab groups 220 and 270 are also bent so that their tip portions face each other.

[0109] FIG. 13 and FIG. 16 are perspective views showing a state in which a holder and a spacer are attached to the electrode body. Next, as shown in FIG. 16, a spacer 600 and an insulating sheet 700 are assembled to the electrode body 200 (step S6).

[0110] Note that the insulating sheet 700 does not necessarily have to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers an area of about 50% or more, more preferably about 70% or more of the outer surface of the electrode body. The insulating sheet 700 preferably covers the entire four surfaces out of the six surfaces of the substantially rectangular parallelepiped (flat shape) electrode body 200, excluding the two surfaces on which the negative electrode tab group 220 and the positive electrode tab group 250 are respectively formed.

[0111] FIG. 17 is a perspective view showing a state in which a sealing plate 120 is attached to the current collector on the negative electrode side. FIG. 18 is a cross-sectional view taken along the XVIII-XVIII line of the electrode body and the current collector shown in FIG. 17. FIGS. 19 and 20 are first and second perspective views showing the form of the spacer 600.

[0112] As shown in FIGS. 19 and 20, the spacer 600 is composed of an insulating resin member. The spacer 600 includes a first component 612 and a second component 614 surrounded by side walls on three sides, and a connecting wall 611 that connects one side wall of each of the first component 612 and the second component 614. Inside the connecting wall 611, a convex portion 616 is provided so as to extend between the first component 612 and the second component 614 (in the Z direction).

[0113] The first component 612 includes a first plate portion 617 provided so as to connect three walls. A plurality of elliptical first through holes 617s are provided in the first plate portion 617. The shape and number of the first through holes 617s are appropriately selected and are not limited to the shapes and quantities shown in the figures.

[0114] The second component 614 includes a second plate portion 618 provided so as to connect three walls. A plurality of elliptical second through holes 618s are provided in the second plate portion 618. The shape and number of the second through holes 618s are appropriately selected and are not limited to the shapes and quantities shown in the figures.

[0115] The above-described first plate portion 617 and second plate portion 618 will be located on the end face side of the electrode body. This plate portion may be in contact with the end face of the electrode body, or even if it is not in contact, the shortest distance is preferably within 2 mm, and more preferably within 1 mm. Further, by providing the first through holes 617s and the second through holes 618s, when the secondary battery 1 shown in FIG. 1 is placed with the Z direction upward (the openings 113 (first opening) and 114 (second opening) at both ends of the case body 110 are arranged left and right), even if the electrolyte extruded from the electrode body to the outside of the electrode body during charging (generally the electrode plates expand) flows out to the outside of this part, it is easy to return into the electrode body during discharging (generally the electrode plates contract).

[0116] As shown in FIGS. 13, 17, and 18, after joining the negative electrode tab group 220 to the current collector 410, joining the negative electrode tab group 270 to the current collector 430, and stacking the first electrode body 201 and the second electrode body 202, the current collector 410 and the current collector 430 are electrically connected to the negative electrode terminal 301 via the current collector 440 (step S7). Note that step S7 can also be performed before step S6.

[0117] Specifically, the negative electrode tab group 220 and the negative electrode tab group 270 are bent such that the tip portions 222 and 272 face each other.

[0118] The negative electrode terminal 301 and the current collector 440 are attached to the sealing plate 120 via an insulating member. The current collector 440 is brought into contact with the current collector 410 and the current collector 430 in the X direction. Note that the connection of the plate-like member 303 to the negative electrode terminal 301 can be made at any timing. The current collector 440 is joined to the current collector 410 and the current collector 430 by laser welding from between the sealing plate 120 and the insulating sheet 700.

[0119] FIG. 21 is a perspective view showing a state where the electrode body is inserted into the case body. As shown in FIGS. 13 and 21, next, after stacking the first electrode body 201 and the second electrode body 202, the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 from the opening 113 with the current collector 420 side at the front (step S8). At this time, at the end portions on the negative electrode tab 230 side of the first electrode body 201 and the second electrode body 202, the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 in a state where the negative electrode active material layer 212 protrudes more toward the negative electrode tab 230 side than the end portion of the positive electrode active material layer 242. Details will be described later.

[0120] By bringing the sealing plate 120 closer to the main body portions of the electrode body 200 (the first electrode body 201 and the second electrode body 202), the negative tab groups 220 and 270 are curved. It is preferable that the sealing plate 120 and the case main body 110 are brought closer to each other by bringing the sealing plate 120 closer to the main body portion of the electrode body 200 disposed within the case main body 110. As shown in FIG. 11, the negative tab groups 220 and 270 are curved along the shape of the spacer 600 such that the folded portions of the curved portions 221 and 271 approach the case main body 110 in the Y direction.

[0121] After bringing the sealing plate 120 into contact with the case main body 110, the sealing plate 120 is temporarily joined to the case main body 110. By the temporary joining, the sealing plate 120 is partially joined to the opening 113 of the case main body 110. Thereby, the sealing plate 120 is positioned with respect to the case main body 110.

[0122] When inserting the electrode body 200 into the case main body 110, the electrode body 200 may be pulled from the current collector 420 side or may be pushed from the current collectors 410 and 430 sides. When the electrode body 200 is pushed from the current collectors 410 and 430 sides, the negative tab groups 220 and 270 can be curved simultaneously.

[0123] FIG. 22 is a perspective view showing a state in which the sealing plate 130 is attached to the current collector on the positive electrode side. FIG. 23 is a cross-sectional view taken along line XXIII-XXIII of the electrode body and the current collector shown in FIG. 22. In FIG. 23, the case main body 110 is omitted.

[0124] As shown in FIGS. 13, 21, and 22, after inserting the first electrode body 201 and the second electrode body 202 into the case main body 110, the current collector 420 is electrically connected to the positive electrode terminal 302 (step S9).

[0125] Specifically, the positive electrode terminal 302 and the current collector 450 are attached to the sealing plate 130 via an insulating member. After the first electrode body 201 and the second electrode body 202 are inserted into the case body 110, the current collector 450 is brought into contact with the current collector 420 protruding from the opening 114 in the X direction. Note that the connection of the plate-like member 304 to the positive electrode terminal 302 may be at any timing.

[0126] As shown in FIG. 23, the positive electrode tab groups 250 and 280 connected to the current collector 420 are bent so that the tip portions 252 and 282 face each other. From the state shown in FIG. 23, the sealing plate 130 is brought into contact with the case body 110. At this time, by bringing the sealing plate 130 closer to the main body portion of the electrode body 200, the positive electrode tab groups 250 and 280 are curved. As shown in FIG. 12, the positive electrode tab groups 250 and 280 are curved along the shape of the spacer 600 so that the folded portions of the curved portions 251 and 281 approach the case body 110 in the Y direction.

[0127] After the sealing plate 130 is brought into contact with the case body 110, the sealing plate 130 is temporarily welded to the case body 110. By the temporary joining, the sealing plate 130 is partially joined to the opening 114 of the case body 110. Thereby, the sealing plate 130 is positioned with respect to the case body 110.

[0128] FIG. 24 is a perspective view showing the configuration of the secondary battery 1. As shown in FIGS. 13 and 24, next, the sealing plate 120 and the sealing plate 130 are joined to the case body 110 (step S10). The sealing plate 120 seals the opening 113 of the case body 110, and the sealing plate 130 seals the opening 114 of the case body 110. Thereby, the first electrode body 201 and the second electrode body 202 are accommodated in the case 100.

[0129] After the above steps, inspections such as leak inspection are performed (step S11). After the leak inspection, the secondary battery 1 is dried to remove moisture inside the case 100. Then, electrolyte is injected into the case 100 from the injection hole 134. When injecting the electrolyte, the case 100 is tilted with the sealing plate 130 upward and the sealing plate 120 downward, and the electrolyte is injected into the case 100 from the injection hole 134 of the sealing plate 130. Then, degassing charging is performed. During degassing charging, the injection hole 134 may be temporarily sealed. Then, the injection hole 134 is sealed, and the secondary battery 1 is completed.

[0130] Note that the order of the electrode body 200 insertion step and the collector connection step is not limited to the above example. For example, after inserting only a part of the electrode body 200 into the case body 110 (first step) so that the end on the opening 113 side in the negative electrode active material layer 212 (second electrode active material layer) is disposed outside the case body 110, the negative electrode terminal 301 (first electrode terminal) provided on the sealing plate 120 (first sealing plate) and the negative electrode tab groups 220, 270 (first electrode tabs) are electrically connected. Then, thereafter, the electrode body 200 may be inserted into the case body 110 (second step) until the end on the opening 113 side in the negative electrode active material layer 212 is disposed inside the case body 110. That is, the negative electrode terminal 301 and the electrode body 200 can be electrically connected during the insertion step of the electrode body 200 into the case body 110.

[0131] In the present embodiment, by providing a negative tab group 220 and a positive tab group 250 on the first electrode body 201, and a negative tab group 270 and a positive tab group 280 on the second electrode body 202, it is possible to configure the first electrode body 201 and the second electrode body 202 to have separate electrode tabs. With this configuration, compared to the case where a single electrode tab is formed by the first electrode body 201 and the second electrode body 202 and this electrode tab is bent, the electrode tab can be shortened. As a result, the occupied volume of the electrode tab can be reduced, so that the energy density of the secondary battery 1 can be improved. Further, the configuration in which separate electrode tabs are provided on the first electrode body 201 and the second electrode body 202 makes it easier to bend the electrode tabs compared to the case where a single electrode tab is formed by the first electrode body 201 and the second electrode body 202. Therefore, it is easy to join the electrode tab and the current collector, and the secondary battery can be manufactured stably. In particular, since the secondary battery 1 can be manufactured stably, the reliability of the connection portion between the electrode tab and the current collector can be increased.

[0132] (Structure of the end portion of the electrode body 200) With reference to FIGS. 25 to 27, the structure of the end portion of the electrode body 200 will be described. FIG. 25 is a cross-sectional view in a plane including the Z-axis in a state where the electrode body is inserted into the case body, FIG. 26 is a cross-sectional view in a plane including the Z-axis showing the schematic configuration of the electrode body 200 after lamination, and FIG. 27 is a cross-sectional view in a plane including the Z-axis showing the schematic configuration of the electrode body 200 after the secondary battery is completed. For the sake of convenience of explanation, in FIGS. 25 to 27, the illustration of the current collector, the case body, and the sealing plate is appropriately omitted.

[0133] With reference to FIG. 25, in the main body portion of the above-described electrode body 200, at the end portion on the positive tab 260 side, the positive electrode protective layer 243 protrudes to the positive tab 260 side more than the end portion of the negative electrode active material layer 212 (X1 in the figure), and at the end portion on the negative tab 230 side, the negative electrode active material layer 212 protrudes to the negative tab 230 side more than the end portion of the positive electrode active material layer 242 (Y1 in the figure).

[0134] The separator 800 has a positive electrode side protruding region 800x (the protruding length is X2 in the figure) that protrudes toward the positive electrode tab 260 side at the end on the positive electrode tab 260 side, beyond the end of the positive electrode protective layer 243, and has a negative electrode side protruding region 800y (the protruding length is Y2 in the figure) that protrudes toward the negative electrode tab 230 side at the end on the negative electrode tab 230 side, beyond the end of the negative electrode active material layer 212. The protruding length (Y2) of the negative electrode side protruding region 800y is set to be larger than the protruding length (X2) of the positive electrode side protruding region 800x (Y2 > X2).

[0135] In the state where the electrode body is inserted into the case body shown in FIG. 21 described above, while the first plate portion 617 and the second plate portion 618 of the spacer 600 are in contact with the end face of the electrode body, more specifically, the negative electrode side protruding region 800y, the electrode body 200 is pushed into the inside of the case body 110 by the external force F applied to the sealing plate 120. At this time, at least a part of the region of the negative electrode side protruding region 800y that contacts the spacer 600 is crushed, and the region of the negative electrode side protruding region 800y that does not contact the spacer 600 remains in its original state while the electrode body 200 is pushed into the inside of the case body 110.

[0136] Here, with reference to FIG. 26, the specific dimensional relationship of the electrode body 200 before being inserted into the case body will be described. On the positive electrode tab 260 side, the protruding length amount X1 of the positive electrode protective layer 243 with respect to the negative electrode active material layer 212 is about 1.0 mm. The protruding length X2 of the positive electrode side protruding region 800x of the separator 800 is about 2.5 mm. Note that the protruding length X2 of the positive electrode side protruding region 800x is preferably 2 mm or more.

[0137] On the negative electrode tab 230 side, the protruding length Y2 of the negative electrode side protruding region 800y is about 3.0 mm. Note that the protruding length Y2 of the negative electrode side protruding region 800y is preferably 2 mm or more.

[0138] Note that the protruding dimension Tx of the positive electrode tab 260 from the end of the positive electrode protective layer 243 and the protruding dimension Ty of the positive electrode tab 260 from the end of the negative electrode active material layer 212 before the electrode body 200 is inserted into the case body are provided with substantially the same dimensions.

[0139] Next, with reference to FIG. 27, the specific dimensional relationships of the electrode body 200 after being inserted into the case body will be described. After the electrode body 200 is inserted into the case body, the configuration on the negative tab 230 side becomes the state shown in FIG. 11, and the configuration on the positive tab 260 side becomes the state shown in FIG. 12.

[0140] On the positive tab 260 side, the positive electrode side protruding region 800x of the separator 800 is in a state where the region in contact with the first plate portion 617 and the second plate portion 618 of the spacer 600 is crushed. The length (X3 in the figure) by which the positive electrode side protruding region 800x is crushed in this case is less than about 1.5 mm. Therefore, the width of the positive electrode side protruding region 800x of the electrode body 200 after being inserted into the case body is about 1.0 mm to 2.5 mm.

[0141] On the other hand, the negative electrode side protruding region 800y of the separator 800 is also in a state where the region in contact with the first plate portion 617 and the second plate portion 618 of the spacer 600 is crushed. The length (Y3 in the figure) by which the negative electrode side protruding region 800y is crushed in this case is larger than that of the positive electrode side protruding region 800x side and exceeds about 1.5 mm. Therefore, the width of the negative electrode side protruding region 800y of the electrode body 200 after being inserted into the case body is about 0.5 mm to 2.5 mm. This is because when the electrode body is inserted into the case body, while the first plate portion 617 and the second plate portion 618 of the spacer 600 are in contact with the negative electrode side protruding region 800y, the electrode body 200 is pushed into the inside of the case body 110 by the external force F applied to the sealing plate 120.

[0142] In this way, although the regions (a total of four locations) of the separator 800 that contact the first plate portion 617 and the second plate portion 618 of the spacers 600 disposed at both ends are crushed, by providing the protruding length of the negative electrode side protruding region 800y to be larger than the protruding length of the positive electrode side protruding region 800x, the negative electrode side protruding region 800y of the separator 800 serves as a cushion, and damage to the negative electrode end portion of the electrode body on the negative electrode tab 230 side can be suppressed when the electrode body 200 is inserted into the case body.

[0143] Furthermore, when injecting the electrolytic solution from the injection hole 134 into the case 100, when the case 100 is erected so that the injection hole 134 is on the upper side (when the X direction is the vertical direction), a load is applied to the negative electrode side protruding region 800y portion on the negative electrode tab 230 side, causing the negative electrode side protruding region 800y portion to bend, and it is possible to suppress the electrolytic solution from flowing out from the end portion of the electrode body during charge and discharge, and it is also possible to suppress Li precipitation near the negative electrode tab 230.

[0144] Furthermore, after the completion of the manufacture of the secondary battery 1, since the distance Ly from the end of the negative electrode active material layer 212 on the negative electrode tab 230 side to the sealing plate 120 side of the spacer 600 is smaller than the distance Lx from the end of the positive electrode protective layer 243 on the positive electrode tab 260 side to the sealing plate 130 side of the spacer 600, it is assumed that the space volume from the end of the negative electrode active material layer 212 on the negative electrode tab 230 side to the sealing plate 120 is smaller than the space volume from the end of the positive electrode protective layer 243 on the positive electrode tab 260 side to the sealing plate 130. Specifically, the protruding dimension Tx of the positive electrode tab 260 from the end of the positive electrode protective layer 243 before the electrode body 200 is inserted into the case body and the protruding dimension Ty of the positive electrode tab 260 from the end of the negative electrode active material layer 212 are provided with substantially the same dimensions. However, after the completion of the manufacture of the secondary battery 1, it is assumed that the distance Hy (the distance from the root of the tab to the current collector) shown in FIG. 12 (positive electrode side) is larger than the distance Hx (the distance from the root of the tab to the current collector) shown in FIG. 11 (negative electrode side).

[0145] (Positive electrode plate and negative electrode plate) Hereinafter, an example of the configuration of the positive electrode plate and the negative electrode plate suitable for the secondary battery 1 according to the present embodiment will be described, but the scope of the present technology is not limited thereto.

[0146] In the positive electrode plate, the positive electrode core 241 is made of a metal foil containing, for example, aluminum, an aluminum alloy, or the like. The thickness of the positive electrode core 241 is, for example, about 3 μm or more, preferably about 5 μm or more. The thickness of the positive electrode core 241 is, for example, about 30 μm or less, preferably about 20 μm or less.

[0147] The positive electrode active material layer 242 contains a positive electrode active material. The positive electrode active material layer 242 may contain, in addition to the positive electrode active material, a binder (such as PVDF) and a conductive member (such as a carbon material). The positive electrode active material is preferably a lithium transition metal composite oxide or the like. The positive electrode active material may be a mixture of a plurality of substances.

[0148] The thickness of the positive electrode active material layer 242 is preferably about 30 μm or more, more preferably about 40 μm or more, and even more preferably about 50 μm or more. The thickness of the positive electrode active material layer 242 is preferably about 500 μm or less, more preferably about 300 μm or less.

[0149] The positive electrode protective layer 243 is a layer having a higher electrical resistance than the positive electrode active material layer 242. The positive electrode protective layer 243 substantially does not contain the positive electrode active material or contains only a trace amount thereof. For example, the mass of the positive electrode active material with respect to the total mass of the positive electrode protective layer 243 is about 5% or less, preferably about 1% or less.

[0150] The positive electrode protective layer 243 preferably contains inorganic particles (such as alumina, boehmite, etc.). The positive electrode protective layer 243 preferably contains inorganic particles and a binder. The positive electrode protective layer 243 preferably contains 50% by mass or more of inorganic particles. The positive electrode protective layer 243 may be an insulating resin layer or may contain a carbon material having conductivity.

[0151] The positive electrode protective layer 243 is preferably formed along the end of the portion where the positive electrode active material layer 242 is formed on the positive electrode core 241. The positive electrode protective layer 243 is preferably disposed so as to face the end of the negative electrode active material layer 212 via a separator (insulating sheet). Thereby, a short circuit between the positive electrode core 241 and the end of the negative electrode active material layer 212 can be suppressed.

[0152] The thickness of the positive electrode protective layer 243 is preferably thinner than the thickness of the positive electrode active material layer 242. The thickness of the positive electrode protective layer 243 is preferably about 10 μm or more, more preferably about 20 μm or more, and even more preferably about 30 μm or more. The thickness of the positive electrode protective layer 243 is preferably about 200 μm or less, more preferably about 100 μm or less, and even more preferably about 50 μm or less.

[0153] In the negative electrode plate, the negative electrode core 211 is preferably made of a metal containing, for example, copper, a copper alloy, etc., and more preferably made of a metal foil.

[0154] The thickness of the negative electrode core 211 is, for example, about 3 μm or more, preferably about 5 μm or more. The thickness of the negative electrode core 211 is, for example, about 30 μm or less, preferably about 20 μm or less.

[0155] The negative electrode active material layer 212 contains a negative electrode active material. The negative electrode active material layer 212 may contain, in addition to the negative electrode active material, a binder (such as SBR, CMC, etc.) and a conductive member (such as a carbon material, etc.). The negative electrode active material is preferably a carbon material such as graphite, a silicon material such as SiO or SiC, etc. The negative electrode active material may be a mixture of a plurality of substances.

[0156] The thickness of the negative electrode active material layer 212 is preferably about 50 μm or more, more preferably about 60 μm or more, and even more preferably about 70 μm or more. The thickness of the negative electrode active material layer 212 is preferably about 500 μm or less, more preferably about 300 μm or less.

[0157] As described above, since the separator 800 is significantly crushed on the negative electrode tab 230 side, it preferably has a certain degree of strength. For example, the tensile fracture strength in the TD direction, which is the direction of crushing, is 500 kgf / cm 2 It is preferable to use the above materials. Examples of the materials include single-layer films or laminated films such as polyethylene and polypropylene with a thickness of about 5 μm to 20 μm. Further, an insulating and heat-resistant layer containing ceramics such as alumina, boehmite, and magnesia and a binder (such as PVDF) may be formed on one or both sides of the separator surface.

[0158] (Other forms of the electrode body) Referring to FIGS. 28 to 30, other forms of the electrode body will be described. FIGS. 29 to 30 are cross-sectional schematic views showing various forms of the electrode body. In the figures, a separator fixing tape 900 is illustrated.

[0159] In the above embodiment, as an example of the electrode body, a so-called single-leaf type laminated electrode body in which an independent separator 800 is disposed between the negative electrode plate 210 and the positive electrode plate 240 as shown in FIG. 28 has been described. However, the form of the electrode body is not limited to this. As shown in FIG. 29, a so-called continuous type laminated electrode body in which one separator 800 is used and disposed to reciprocate between the negative electrode plate 210 and the positive electrode plate 240 may be used. Further, as shown in FIG. 30, a wound type electrode body in which the separator 800 is disposed between the negative electrode plate 210 and the positive electrode plate 240 and wound around an axis may be used.

[0160] In the above embodiment, since it is expected that the negative electrode tab 230 side of the separator 800 will be crushed, if there is a separator extending in the thickness direction (Y direction) of the electrode body, there is a possibility that the crushing on the negative electrode tab 230 side will be inhibited. Therefore, in the order of the single-leaf type, the continuous type, and the wound type, the effect of this preferable crushing can be obtained.

[0161] On the other hand, by laminating, the rapid charging performance is higher than that of winding. Furthermore, among laminations, it is considered that the folded portion of the separator at the upper and lower ends has higher rigidity in the continuous type than in the single-sheet type, and it is less likely to damage the electrode plate. Therefore, it is considered to be suitable for the process of inserting the electrode body into the case body and the process of injecting the electrolytic solution into the case in the present embodiment.

[0162] As described above, in the technology of the present disclosure, it is possible to avoid the risk of damaging the electrode body when inserting the electrode body into the battery case and / or when standing the case during liquid injection. As a result, it is possible to provide a secondary battery with high energy density and high reliability and a method for manufacturing the same.

[0163] As described above, the embodiments of the present technology have been described. However, it should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

Description of Reference Numerals

[0164] 1 Secondary battery, 100 Case, 110 Case body, 111 First side surface part, 112, 112A, 112B Second side surface part, 113, 114 Opening, 115 Joint part, 120, 130 Sealing plate, 134 Liquid injection hole, 150 Gas discharge valve, 200 Electrode body, 201 First electrode body, 202 Second electrode body, 205 First end part, 206 Second end part, 207 Third end part, 208 Fourth end part, 210 Negative electrode plate, 211 Negative electrode core, 212 Negative electrode active material layer, 220, 270 Negative electrode tab groups, 221, 251, 271, 281 Curved part, 222, 252, 272, 282 Tip part, 230 Negative electrode tab, 240 Positive electrode plate, 241 Positive electrode core, 242 Positive electrode active material layer, 243 Positive electrode protective layer, 250, 280 Positive electrode tab groups, 260 Positive electrode tab, 300 Electrode terminal, 301 Negative electrode terminal, 302 Positive electrode terminal, 303, 304 Plate-like members, 400, 410, 420, 430, 440, 450 Current collector, 400A Negative electrode current collector, 400B Positive electrode current collector, 411, 421, 431 Joint location, 510, 520, 530 Insulating member, 600 Spacer, 611 Connecting wall, 612 First component, 614 Second component, 616 Protrusion, 617 First plate part, 617s First through hole, 618 Second plate part, 618s Second through hole, 700 Insulating sheet, 800 Separator, 800x Positive electrode side protruding region, 800y Negative electrode side protruding region, 900 Separator fixing tape.

Claims

1. An electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator, and a case for housing the electrode body, wherein the case includes a case body having a first opening at one end and a second opening at the other end, a first sealing plate for sealing the first opening, and a second sealing plate for sealing the second opening, a first spacer is disposed between the first sealing plate and the electrode body, a second spacer is disposed between the second sealing plate and the electrode body, the positive electrode plate has a positive electrode tab at an end on the second sealing plate side, the negative electrode plate has a negative electrode tab at an end on the first sealing plate side, the positive electrode plate includes a positive electrode core, a positive electrode active material layer formed on the positive electrode core, and a positive electrode protection layer formed on the positive electrode core, in the positive electrode plate, the positive electrode protection layer is located on the positive electrode tab side with respect to the positive electrode active material layer, the negative electrode plate includes a negative electrode core and a negative electrode active material layer formed on the negative electrode core, the separator, at the end on the positive electrode tab side, has a positive electrode side protruding region protruding on the positive electrode tab side with respect to the end of the positive electrode protection layer, at the end on the negative electrode tab side, has a negative electrode side protruding region protruding on the negative electrode tab side with respect to the end of the negative electrode active material layer, the separator has a region crushed by the first spacer in the negative electrode side protruding region, a secondary battery.

2. the separator has a region crushed by the second spacer in the positive electrode side protruding region, the width of the crushed negative electrode side protruding region is larger than the width of the crushed positive electrode side protruding region, The secondary battery according to Claim 1.

3. the separator has a larger width of the negative electrode side protruding region than the width of the positive electrode side protruding region, The secondary battery according to Claim 1.

4. The space volume from the end of the negative electrode active material layer to the first sealing plate is smaller than the space volume from the end of the positive electrode protection layer to the second sealing plate, The secondary battery according to Claim 1.

5. A step of manufacturing an electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator, and a step of housing the electrode body in a case, wherein the case includes a case body having a first opening at one end and a second opening at the other end, a first sealing plate for sealing the first opening, and a second sealing plate for sealing the second opening, the step of housing the electrode body in the case includes inserting the electrode body into the case body through the first opening, The electrode body has a main body portion, a positive electrode tab provided on the positive electrode plate and located on the second sealing plate side with respect to the main body portion, and a negative electrode tab provided on the negative electrode plate and located on the first sealing plate side with respect to the main body portion. The positive electrode plate includes a positive electrode core body, a positive electrode active material layer formed on the positive electrode core body, and a positive electrode protective layer formed on the positive electrode core body. In the positive electrode plate, the positive electrode protective layer is located on the positive electrode tab side with respect to the positive electrode active material layer. The negative electrode plate includes a negative electrode core body and a negative electrode active material layer formed on the negative electrode core body. In the main body portion of the electrode body, At the end on the positive electrode tab side, the positive electrode protective layer protrudes on the positive electrode tab side with respect to the end of the negative electrode active material layer. At the end on the negative electrode tab side, the negative electrode active material layer protrudes on the negative electrode tab side with respect to the end of the positive electrode active material layer. The separator At the end on the positive electrode tab side, it has a positive electrode side protruding region that protrudes on the positive electrode tab side with respect to the end of the positive electrode protective layer. At the end on the negative electrode tab side, it has a negative electrode side protruding region that protrudes on the negative electrode tab side with respect to the end of the negative electrode active material layer. The protruding length of the negative electrode side protruding region is greater than the protruding length of the positive electrode side protruding region. Method for manufacturing a secondary battery.

6. Both the protruding length of the negative electrode side protruding region and the protruding length of the positive electrode side protruding region are 2 mm or more. The method for manufacturing a secondary battery according to claim 5.

7. In the step of inserting the electrode body into the case body from the first opening, It includes the step of inserting the electrode body into the case body from the first opening with a spacer disposed between the first sealing plate and the electrode body. The negative electrode side protruding region is housed in the case body so as to be crushed in the region where it abuts against the spacer. The method for manufacturing a secondary battery according to claim 5.

8. Inserting the electrode body into the case body from the end of the electrode body on the side where the positive electrode tab is disposed. The method for manufacturing a secondary battery according to claim 5.

9. After connecting the negative electrode tab and the first sealing plate, inserting the electrode body into the case body. The method for manufacturing a secondary battery according to claim 8.

10. After inserting the electrode body into the case body, connecting the positive electrode tab and the second sealing plate. The method for manufacturing a secondary battery according to claim 8.

11. Electrically connecting the negative electrode tab to the negative electrode terminal attached to the first sealing plate via a negative electrode current collector. The method for manufacturing a secondary battery according to claim 5.

12. Electrically connecting the positive electrode tab to the positive electrode terminal attached to the second sealing plate via a positive electrode current collector. The method for manufacturing a secondary battery according to claim 5.

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