Secondary battery and method for manufacturing same

Abstract

The invention provides a secondary battery and a manufacturing method thereof. In the method for manufacturing the secondary battery, in the main body part of the electrode body, the separator has a positive electrode-side protruding region that protrudes further toward the positive electrode tab side than the end part of the positive electrode protective layer at the end part of the positive electrode tab side. The negative electrode active material layer has a negative electrode-side protruding region that protrudes further toward the negative electrode tab side than an end portion of the negative electrode active material layer at an end portion on the negative electrode tab side, and the separator has a region that is collapsed by the first separator in the negative electrode-side protruding region.

Description

Technical Field

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

[0002] The following structure is disclosed in U.S. Patent Publication No. 2022 / 0302533: electrode tab groups are provided at both ends of the electrode body, and the electrode tab groups are connected to electrode terminals at both ends of the length direction of the battery case. By providing components for accommodating the electrode tab groups at both ends of the battery case, the shape of the electrode tab group is simplified, and the length of the current collection path is suppressed from becoming longer. Summary of the invention

[0003] When the electrode body is inserted into the battery case and / or when the case is raised during liquid injection, the electrode body (negative electrode active material layer at the corner) may be damaged. Furthermore, when the electrode body is inserted into the battery case and / or when the case is raised during liquid injection, the negative terminal at the lower end may come into contact with the separator or the current collector and be damaged.

[0004] The present technology aims to avoid the possibility of damage to the electrode body when inserting the electrode body into the battery case and / or when the case is erected during liquid injection, thereby providing a secondary battery with high energy density and high reliability and a method for manufacturing the same.

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

[0006] [1] A secondary battery, wherein the secondary battery comprises: an electrode body, the electrode body having a positive electrode plate and a negative electrode plate stacked with a separator therebetween; and a shell, the shell accommodating the electrode body, the shell comprising: a shell body having a first opening at one end and a second opening at the other end; a first sealing plate sealing the first opening; and a second sealing plate sealing the second opening, a first separator being arranged between the first sealing plate and the electrode body, and a second separator being arranged between the second sealing plate and the electrode body, the positive electrode plate having a positive electrode tab at an end on the second sealing plate side, and the negative electrode plate having a negative electrode tab at an end on the first sealing plate side, and the positive electrode plate comprising: A positive electrode core; a positive electrode active material layer formed on the above-mentioned positive electrode core; and a positive electrode protective layer formed on the above-mentioned positive electrode core, in the above-mentioned positive electrode plate, the above-mentioned positive electrode protective layer is located on the above-mentioned positive electrode ear side compared with the above-mentioned positive electrode active material layer, and the above-mentioned negative electrode plate comprises: a negative electrode core; and a negative electrode active material layer formed on the above-mentioned negative electrode core, the above-mentioned separator has an end portion on the above-mentioned positive electrode ear side having a positive electrode side protruding area protruding toward the above-mentioned positive electrode ear side compared with the end portion of the above-mentioned positive electrode protective layer, and has an end portion on the above-mentioned negative electrode ear side having a negative electrode side protruding area protruding toward the above-mentioned negative electrode ear side compared with the end portion of the above-mentioned negative electrode active material layer, and the above-mentioned separator has an area collapsed by the above-mentioned first separator in the above-mentioned negative electrode side protruding area.

[0007] [2] The secondary battery according to [1], wherein the separator has a region in the positive electrode side protruding region that is collapsed by the second separator, and the collapsed width of the negative electrode side protruding region is larger than the collapsed width of the positive electrode side protruding region.

[0008] [3] The secondary battery according to [1] or [2], wherein, in the separator, the width of the negative electrode side protruding region is greater than the width of the positive electrode side protruding region.

[0009] [4] The secondary battery according to any one of [1] to [3], wherein the volume of the space from the end of the negative electrode active material layer to the first sealing plate is smaller than the volume of the space from the end of the positive electrode protection layer to the second sealing plate.

[0010] [5] A method for manufacturing a secondary battery, wherein the method for manufacturing the secondary battery comprises: a step of making an electrode body having a positive electrode plate and a negative electrode plate stacked with a separator; and a step of accommodating the electrode body in a shell, the shell comprising: a shell 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 accommodating the electrode body in the shell comprising the step of inserting the electrode body into the shell body from the first opening, the electrode body comprising: a main body; a positive electrode tab disposed on the positive electrode plate at a side of the second sealing plate relative to the main body; and a negative electrode tab disposed on the negative electrode plate at a side of the first sealing plate relative to the main body, the positive electrode plate comprising: a positive electrode core; a positive electrode active material layer formed on the positive electrode core; and a positive electrode active material layer formed on the positive electrode core A positive electrode protective layer on the body, in the above-mentioned positive electrode plate, the above-mentioned positive electrode protective layer is located on the above-mentioned positive electrode ear side compared with the above-mentioned positive electrode active material layer, the above-mentioned negative electrode plate comprises: a negative electrode core; and a negative electrode active material layer formed on the above-mentioned negative electrode core, in the above-mentioned main body of the above-mentioned electrode body, at the end part on the above-mentioned positive electrode ear side, the above-mentioned positive electrode protective layer protrudes toward the above-mentioned positive electrode ear side compared with the end part of the above-mentioned negative electrode active material layer, and at the end part on the above-mentioned negative electrode ear side, the above-mentioned negative electrode active material layer protrudes toward the above-mentioned negative electrode ear side compared with the end part of the above-mentioned positive electrode active material layer, the above-mentioned separator has a positive electrode side protruding area at the end part on the above-mentioned positive electrode ear side that protrudes toward the above-mentioned positive electrode ear side compared with the end part of the above-mentioned positive electrode protective layer, and has a negative electrode side protruding area at the end part on the above-mentioned negative electrode ear side that protrudes toward the above-mentioned negative electrode ear side compared with the end part of the above-mentioned negative electrode active material layer, and the protruding length of the above-mentioned negative electrode side protruding area is greater than the protruding length of the above-mentioned positive electrode side protruding area.

[0011] [6] The method for manufacturing a secondary battery according to [5], wherein the protrusion length of the negative electrode side protrusion region and the protrusion length of the positive electrode side protrusion region are both greater than 2 mm.

[0012] [7] A method for manufacturing a secondary battery as described in [5] or [6], wherein the step of inserting the electrode body from the first opening into the shell body includes the step of inserting the electrode body from the first opening into the shell body in a state where a spacer is arranged between the first sealing plate and the electrode body, and the negative electrode side protruding area is accommodated in the shell body in a manner that is collapsed in the area abutting against the spacer.

[0013] [8] The method for manufacturing a secondary battery according to any one of [5] to [7], wherein the electrode body is inserted into the case body from the end of the electrode body on the side where the positive electrode tab is arranged.

[0014] [9] The method for manufacturing a secondary battery according to [8], wherein the electrode body is inserted into the case body after the negative electrode tab and the first sealing plate are connected.

[0015]

[10] The method for manufacturing a secondary battery according to [8], wherein the positive electrode tab and the second sealing plate are connected to each other after the electrode body is inserted into the case body.

[0016]

[11] The method for manufacturing a secondary battery according to any one of [5] to

[10] , wherein the negative electrode tab is electrically connected to the negative electrode terminal attached to the first sealing plate via a negative electrode collector.

[0017]

[12] The method for manufacturing a secondary battery according to any one of [5] to

[10] , wherein the positive electrode tab is electrically connected to the positive electrode terminal attached to the second sealing plate via a positive electrode collector.

[0018] The foregoing and other objects, features, configurations 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

[0019] Figure 1 It is a front view showing the structure of a secondary battery according to one embodiment.

[0020] Figure 2 It is shown when viewed from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0021] Figure 3 It shows the direction of arrow III. Figure 1 A diagram showing the state of a secondary battery.

[0022] Figure 4 It is shown when viewed from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0023] Figure 5 It shows the direction of arrow V. Figure 1 A diagram showing the state of a secondary battery.

[0024] Figure 6 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0025] Figure 7 It is a cross-sectional view of the negative plate.

[0026] Figure 8 It is a front view showing the negative electrode plate.

[0027] Fig. 9 It is a cross-sectional view of the positive plate.

[0028] Fig.10 It is a front view showing the positive electrode plate.

[0029] Fig.11 yes Figure 1 XI-XI cross-sectional view of the secondary battery shown.

[0030] Fig.12 yes Figure 1 A cross-sectional view taken along line XII-XII of the secondary battery shown.

[0031] Fig.13 1 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment.

[0032] Fig.14 It is a perspective view showing a state before two electrode bodies included in a secondary battery according to an embodiment are overlapped.

[0033] Fig.15 yes Fig.14 The electrode body and the current collector are shown in a cross-sectional view taken along the line XV-XV.

[0034] Fig.16 It is a perspective view showing a state where a holder and a separator are attached to the electrode body.

[0035] Fig.17 It is a perspective view showing a state where a sealing plate is attached to the current collector on the negative electrode side.

[0036] Fig.18 yes Fig.17 XVIII-XVIII cross-sectional view of the electrode body and the current collector shown.

[0037] Fig.19 This is a first perspective view showing the form of the spacer.

[0038] Fig. 20 This is a second perspective view showing the form of the spacer.

[0039] Fig.21 It is a perspective view showing a state where the electrode body is inserted into the case body.

[0040] Fig. 22 It is a perspective view showing a state where a sealing plate is attached to the current collector on the positive electrode side.

[0041] Fig.23 yes Fig. 22 XXIII-XXIII cross-sectional view of the electrode body and the current collector shown.

[0042] Fig.24 It is a perspective view showing the structure of a secondary battery.

[0043] Fig.25 It is a cross-sectional view taken along a plane including the Z axis, showing a state in which the electrode body is inserted into the case body.

[0044] Fig.26 It is a cross-sectional view taken along a plane including the Z axis, showing a schematic structure of the electrode body after stacking.

[0045] Fig. 27 It is a cross-sectional view taken along a plane including the Z axis, showing a schematic structure of an electrode body after the secondary battery is completed.

[0046] Fig.28 Schematic cross-sectional views showing various forms (leaf-shaped) of electrode bodies.

[0047] Fig.29 Schematic cross-sectional views showing various forms (bending forms) of electrode bodies.

[0048] Fig.30 Schematic cross-sectional views showing various forms (wound types) of electrode bodies. DETAILED DESCRIPTION

[0049] 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.

[0050] In addition, in the embodiments described below, when the number, amount, etc. are mentioned, unless otherwise specified, the scope of the present technology is not necessarily limited to the number, amount, etc. In addition, in the following embodiments, each component is not an essential component for the present technology unless otherwise specified. In addition, the present technology is not limited to a configuration that necessarily exerts all the effects mentioned in the embodiments.

[0051] In addition, in this specification, the descriptions such as "comprise", "include", and "have" are not limiting. That is, when a certain structure is included, other structures other than the structure may be included or not.

[0052] In addition, in this specification, when geometrical terms and terms indicating position and direction relationships such as "parallel", "orthogonal", "oblique 45 degrees", "coaxial", "along" and the like are used, these terms allow for manufacturing errors or slight variations. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used as terms indicating 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.).

[0053] In this specification, "secondary battery" is not limited to lithium ion batteries, and may also include other secondary batteries such as nickel-hydrogen batteries and sodium ion batteries. In this specification, the positive electrode and the negative electrode may be collectively referred to as "electrodes".

[0054] In addition, in the drawings, when the electrode body of the secondary battery is a laminated electrode body, the long side direction of the laminated surface is set to the X direction, and when the electrode body is a wound electrode body, the direction along the winding axis is set to the X direction. In addition, when viewed from the X direction, the short side direction of the electrode body is set to the Y direction, and when viewed from the X direction, the long side direction of the electrode body is set to the Z direction. In order to facilitate the understanding of the present technology, the dimensions of each component in the drawings are sometimes shown with some changes relative to the actual dimensions.

[0055] In the present application specification, the first direction (X direction) is sometimes referred to as the "width direction" of the secondary battery or the shell body, the second direction (Z direction) is similarly referred to as the "height direction" of the secondary battery or the shell body, and the third direction (Y direction) is similarly referred to as the "thickness direction" of the secondary battery or the shell body.

[0056] (Overall structure of the battery)

[0057] Figure 1 It is a front view of the secondary battery 1 which concerns on one embodiment. Figures 2 to 5 They are respectively shown as 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.

[0058] The secondary battery 1 can be mounted on a battery 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.

[0059] like Figures 1 to 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 sealing plate 120 (first sealing plate), and a sealing plate 130 (second sealing plate).

[0060] 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 on the side surface of the battery pack housing without using a constraining member.

[0061] The case body 110 is formed of a cylindrical (preferably a square cylindrical) member. Thus, a square secondary battery 1 can be obtained. The case body 110 is made of metal. Specifically, the case body 110 is formed of aluminum, aluminum alloy, iron, or iron alloy.

[0062] like Figure 1 , Figure 2 As shown in FIG. 1 , a sealing plate 120 (first wall) and a sealing plate 130 (second wall) are provided at both ends of the shell body. The shell body 110 can be formed by, for example, bringing the ends of the plate-like members that have been bent into contact with each other ( Figure 2 The illustrated joint 115) is joined to each other (eg, laser welded) to form a square tube shape. The corners of the "square tube shape" may also have an R angle (rounded corner) shape. In addition, the secondary battery in the present technology is not necessarily limited to a square secondary battery.

[0063] In the present embodiment, the shell body 110 is formed to be longer in the width direction (X direction) of the secondary battery 1 than in the thickness direction (Y direction) and the height direction (Z direction) of the secondary battery 1. The dimension (width) of the shell body 110 in the X direction is preferably about 30 cm or more. 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 about 20 cm or less, more preferably about 15 cm or less, and further preferably about 10 cm or less. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved.

[0064] The shell 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 part of the side of the shell 100. The pair of second side portions 112 constitute the bottom portion and the top portion of the shell 100. The pair of first side portions 111 and the pair of second side portions 112 are respectively arranged in a mutually intersecting manner. The pair of first side portions 111 and the pair of second side portions 112 are connected at their respective ends. Preferably, the area of ​​each of the pair of first side portions 111 is larger than the area of ​​each of the pair of second side portions 112.

[0065] like Figure 5 As shown in FIG. 1 , a gas discharge valve 150 is provided on the second side surface 112A of one of the pair of second side surfaces 112. 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 from the center of the housing body 110 in the X direction to an extent that it does not reach both ends. The gas discharge valve 150 can be appropriately changed.

[0066] The thickness of the plate-shaped member at the gas discharge valve 150 is thinner than the thickness of the plate-shaped member of the housing body 110 other than the gas discharge valve 150. Therefore, when the pressure in the housing 100 becomes equal to or higher than a predetermined value, the gas discharge valve 150 breaks preferentially compared to other parts in the housing body 110, and the gas in the housing 100 is discharged to the outside.

[0067] like Figure 2 As shown, a joint 115 is formed on the other second side surface 112B of the pair of second side surfaces 112. The joint 115 extends in the width direction (X direction) of the secondary battery 1. At the joint 115, the edges of the plate-like members constituting the case body 110 are joined to each other.

[0068] like Figure 3 As shown in the figure, an opening 113 (first opening) is provided at the end of the first side in the first direction (X direction) of the housing body 110. The opening 113 is sealed by a sealing plate 120. A joint 115 is formed in the opening 113 to seal the opening 113. The opening 113 and the 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. In addition, the substantially rectangular shape includes a substantially rectangular shape such as a rectangular shape or a substantially rectangular shape such as a shape with rounded corners of a rectangular shape.

[0069] The sealing plate 120 (first sealing plate) is provided with a negative electrode terminal 301. The position of the negative electrode terminal 301 can be changed as appropriate.

[0070] like Figure 4As shown in the figure, an opening 114 (second opening) is provided at the end of the second side opposite to the first side in the first direction (X direction) of the housing body 110. That is, the opening 114 is located at the end opposite to the opening 113, and the openings 113 and 114 face each other. The opening 114 is sealed by the sealing plate 130. A joint 115 is formed at the opening 114 to seal the opening 114. The opening 114 and the 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.

[0071] The sealing plate 130 (second sealing plate) is provided with a positive electrode terminal 302 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.

[0072] 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, aluminum alloy, iron, iron alloy, or the like.

[0073] 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.

[0074] 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.

[0075] The negative electrode terminal 301 may be 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 .

[0076] 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.

[0077] 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.

[0078] The electrode body 200 is a flat electrode body in which a positive electrode plate and a negative electrode plate described later are stacked. Specifically, the electrode body 200 is a laminated electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked with a separator 800 described later (see Fig.29 However, in this specification, the term "electrode body" is not limited to a laminated electrode body, but may be a wound electrode body in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound together with a strip-shaped separator (see the following). Fig.30). The separator may be composed of a microporous film made of polyolefin, for example. In the case where 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.

[0079] like Figure 6 As shown in FIG. 1 , the housing 100 accommodates the electrode body 200. Figure 6 In FIG. 1 , a first electrode body 201 described later is illustrated. The first electrode body 201 is housed in the housing 100 so that the longitudinal direction thereof is parallel to the X direction.

[0080] Specifically, a single or multiple laminated electrode bodies are housed inside the insulating sheet 700 described later and an electrolyte (electrolyte) not shown in the figure. As the electrolyte (non-aqueous electrolyte), for example, the following electrolyte can be used: LiPF6 is dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio (25° C.) of 30:30:40. In addition, a solid electrolyte can be used instead of an electrolyte.

[0081] The first electrode body 201 includes a substantially rectangular main body, a negative electrode tab group 220 (a first electrode tab group), and a positive electrode tab group 250 (a second electrode tab group).

[0082] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240 described later. The negative electrode tab group 220 is located at an end of the first side of the first electrode body 201 in the first direction (X direction) relative to the main body. The first side in this embodiment is the sealing plate 120 side. The positive electrode tab group 250 is located at an end 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 sealing plate 130 side.

[0083] The negative electrode tab group 220 and the positive electrode 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.

[0084] 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 .

[0085] The negative electrode current collector 400A is arranged on the sealing plate 120 via an insulating member made of resin. The negative electrode current collector 400A is electrically connected to the negative electrode tab group 220 and the negative electrode terminal 301. The negative electrode current collector 400A is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy. In addition, the details of the negative electrode current collector 400A will be described later.

[0086] The positive electrode collector 400B is arranged on the sealing plate 130 via an insulating member made of resin. The positive electrode collector 400B is electrically connected to the positive electrode tab group 250 and the positive terminal 302. The positive electrode collector 400B is composed of a conductive material (more specifically a metal), for example, aluminum or an aluminum alloy. In addition, the positive electrode tab group 250 can also be electrically connected to the sealing plate 130 directly or via the positive electrode collector 400B. In this case, the sealing plate 130 can also play the role of the positive terminal 302. In addition, the details of the positive electrode collector 400B are described later.

[0087] (Configuration of Electrode Body 200)

[0088] Figure 7 is a cross-sectional view of the negative electrode plate 210 ( Figure 8 VII-VII section view in the figure), Figure 8 2 is a front view showing the negative electrode plate 210 .

[0089] like Figure 8 As shown, at one end of the width direction of the negative electrode plate 210, a plurality of negative electrode tabs 230 (first electrode tabs) formed of a negative electrode core 211 are provided. 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. Considering the state of connection between the negative electrode tab group 220 and the negative electrode collector 400A, the length of the protruding direction of each of the negative electrode tabs 230 in the plurality of negative electrode plates 210 can be appropriately adjusted. In addition, the shape of the negative electrode tab 230 is not limited to Figure 7 The illustrated shape.

[0090] Fig. 9 is a cross-sectional view of the positive electrode plate 240 ( Fig.10 IX-IX section view in the figure), Fig.10 1 is a front view showing the positive electrode plate 240 .

[0091] like Fig.10As shown, at one end of the width direction of the formed positive electrode plate 240, a plurality of positive electrode tabs 260 (second electrode tabs) formed of a positive electrode core 241 are provided. When the positive electrode plates 240 are stacked, a plurality of positive electrode tabs 260 are stacked to form a positive electrode tab group 250. Considering the state of connection between the positive electrode tab group 250 and the positive electrode collector 400B, the length of the protruding direction of each positive electrode tab 260 in the plurality of positive electrode plates 240 can be appropriately adjusted. In addition, the shape of the positive electrode tab 260 is not limited to Fig.10 The illustrated shape.

[0092] The positive electrode protection layer 243 is provided at the root of the positive electrode tab 260. The positive electrode protection layer 243 does not necessarily need to be provided at the root of the positive electrode tab 260.

[0093] In a typical example, the thickness of the negative electrode tab 230 (one) is smaller than the thickness of the positive electrode tab 260 (one). In this case, the thickness of the negative electrode tab group 220 is smaller than the thickness of the positive electrode tab group 250.

[0094] (Connection Structure of Electrode Body 200 and Current Collector 400)

[0095] Fig.11 yes Figure 1 XI-XI cross-sectional view of the secondary battery shown in FIG. Fig.11 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 positive electrode (second electrode) and a negative electrode (first electrode), respectively. Alternatively, the electrode body 200 may be composed of three or more electrode bodies.

[0096] The electrode body 200 is formed by stacking a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 are arranged in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0097] 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 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 207 in the X direction.

[0098] The negative electrode tab group 220 has a bent portion 221 and a terminal portion 222. The bent portion 221 is a portion of the negative electrode tab group 220 bent on the side connected to the first electrode relative to the terminal portion 222. The terminal portion 222 is a portion of the negative electrode tab group 220 located at the end opposite to the side connected to the first electrode.

[0099] The negative electrode tab group 270 has a bent portion 271 and a terminal portion 272. The bent portion 271 is a portion of the negative electrode tab group 270 bent on the side connected to the first electrode relative to the terminal portion 272. The terminal portion 272 is a portion of the negative electrode tab group 270 located at the end opposite to the side connected to the first electrode.

[0100] The negative electrode tab group 220 and the negative electrode tab group 270 are bent in opposite directions so that the terminal portions 222 and 272 approach each other. In the present embodiment, the terminal portions 222 and 272 are separated, but the present invention is not limited to this configuration, and the terminal portions 222 and 272 may contact each other.

[0101] The negative electrode current collector 400A is electrically connected to the negative electrode terminal 301 and the negative electrode tab group 220 and the negative electrode tab group 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 sealing plate 120.

[0102] The negative electrode current collector 400A includes a current collector 410 , a current collector 430 (third current collecting member), and a current collector 440 (fourth current collecting member).

[0103] The current collector 410 is a plate-shaped member. The current collector 410 has a long side direction in the Z direction and a short side direction in the Y direction. The current collector 430 is a plate-shaped member. The current collector 430 has a long side 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 side by side in the X direction. In this way, the current collector 410 and the current collector 430 are composed of separate components.

[0104] 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 and 431 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. 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, for example, by ultrasonic welding.

[0105] The current collector 440 is joined to the current collector 410 and the current collector 430 at a joint portion (not shown) located at an end 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 caulking and / or welding, for example.

[0106] The negative electrode terminal 301 is exposed to the outside of the sealing plate 120 and is provided so as to 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.

[0107] The plate-shaped member 303 is located outside the sealing plate 120. The plate-shaped member 303 is arranged along the sealing plate 120. The plate-shaped member 303 has conductivity. The plate-shaped member 303 is arranged for the purpose of ensuring a connection area with a bus bar that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the negative terminal 301 and the plate-shaped member 303 can be formed by, for example, laser welding.

[0108] An insulating member 510 is disposed between the plate-shaped member 303 and the sealing plate 120 . An insulating member 520 is disposed between the negative electrode terminal 301 and the sealing plate 120 . An insulating member 530 is disposed between the current collector 440 and the sealing plate 120 .

[0109] However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120 . In addition, the sealing plate 120 may also play the role of the negative electrode terminal 301 .

[0110] A separator 600 (first separator) described below is disposed between the sealing plate 120 and the main body portion (excluding the negative electrode tab group 220) of the electrode body 200. The separator 600 is made of an insulating resin member.

[0111] The detailed structure of the spacer 600 will be described later, and the spacer 600 is provided with a convex portion 616 protruding in the Y direction. The convex portion 616 of the spacer 600 plays a guiding role in making the curved portions 221 and 271 easier to bend when the curved portions 221 and 271 are bent.

[0112] An insulating sheet 700 (electrode body support) made of resin is disposed between the electrode body 200 and the case body 110. The insulating sheet 700 may be made of, for example, resin. More specifically, the insulating sheet 700 may be made of, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0113] Fig.12 yes Figure 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 this embodiment is different from that on the negative electrode side in that the portion corresponding to the current collector 410 and the current collector 430 on the negative electrode side is formed of one member.

[0114] The first electrode body 201 includes a positive electrode tab group 250. The positive electrode tab group 250 is electrically connected to the current collector 420 (positive electrode current collector) at the second end 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 the current collector 420 (positive electrode current collector) at the fourth end 208 in the X direction.

[0115] The positive electrode tab group 250 has a bent portion 251 and a terminal portion 252. The bent portion 251 is a portion of the positive electrode tab group 250 bent on the side connected to the second electrode relative to the terminal portion 252. The terminal portion 252 is a portion of the positive electrode tab group 250 located at the end opposite to the side connected to the second electrode.

[0116] The positive electrode tab group 280 has a bent portion 281 and a terminal portion 282. The bent portion 281 is a portion of the positive electrode tab group 280 bent on the side connected to the second electrode relative to the terminal portion 282. The terminal portion 282 is a portion of the positive electrode tab group 280 located at the end opposite to the side connected to the second electrode.

[0117] The positive electrode tab group 250 and the positive electrode tab group 280 are bent in opposite directions so that the terminal portions 252 and 282 approach each other. In the present embodiment, the terminal portions 252 and 282 are separated, but the present invention is not limited to this configuration, and the terminal portions 252 and 282 may be in contact with each other.

[0118] 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 this embodiment is connected to the positive electrode terminal 302 between the electrode body 200 and the sealing plate 130.

[0119] The positive electrode current collector 400B includes a current collector 420 (first current collecting member) and a current collector 450 (second current collecting member).

[0120] The current collector 420 is a plate-shaped member. The current collector 420 has a long side direction in the Z direction and a short side direction in the Y direction. The current collector 420 is composed of a single integral member.

[0121] The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the 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 positive electrode tab group 250 and the positive electrode tab group 280 and the collector 420 are joined, for example, by ultrasonic joining.

[0122] The current collector 450 is joined to the current collector 420 at a joining portion (not shown) located at an 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 by caulking and / or welding, for example.

[0123] The positive electrode terminal 302 is exposed to the outside of the sealing plate 130 and is provided so as to 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 .

[0124] The plate-shaped member 304 is located outside the sealing plate 130. The plate-shaped member 304 is arranged along the sealing plate 130. The plate-shaped member 304 has conductivity. The plate-shaped member 304 is arranged for the purpose of ensuring a connection area with a bus bar that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the positive terminal 302 and the plate-shaped member 304 can be formed by laser welding, for example.

[0125] An insulating member 510 is disposed between the plate-shaped member 304 and the sealing plate 130 . An insulating member 520 is disposed between the positive electrode terminal 302 and the sealing plate 130 . An insulating member 530 is disposed between the current collector 450 and the sealing plate 130 .

[0126] However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130 . In addition, the sealing plate 130 may also play the role of the positive electrode terminal 302 .

[0127] A separator 600 (second separator) is disposed between the sealing plate 130 and the main body portion (excluding the positive electrode tab group 250 and 280 ) of the electrode body 200 . The separator 600 is made of an insulating resin member.

[0128] The detailed structure of the spacer 600 will be described later, and the spacer 600 is provided with a convex portion 616 protruding in the Y direction. The convex portion 616 of the spacer 600 plays a guiding role in making the bending portions 251 and 281 easy to bend when bending.

[0129] The above-mentioned insulating sheet 700 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110 .

[0130] (Manufacturing process of secondary battery 1)

[0131] Hereinafter, a method for manufacturing the secondary battery according to the present embodiment will be described. Fig.13 This is a flowchart showing the method for manufacturing the secondary battery according to the first embodiment. Fig.14 This is a perspective view showing a state before two electrode bodies according to the secondary battery according to the first embodiment are stacked. Fig.15 yes Fig.14 The electrode body and the current collector are shown in a cross-sectional view taken along the line XV-XV.

[0132] like Fig.13As shown, in the manufacturing method of the secondary battery involved in this embodiment, first, the first electrode body 201 and the second electrode body 202 are manufactured (S1 process). 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 are respectively cut off part of the end so that the length of the end becomes the same length when tied.

[0133] like Figure 13 to Figure 15 As shown, after the first electrode body 201 and the second electrode body 202 are manufactured, 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.

[0134] Next, the first electrode body 201, the current collector 420, and the second electrode body 202 are arranged in the first direction (DR1 direction) in sequence. The positive electrode tab group 250 is arranged on one side of the current collector 420 in the first direction (DR1 direction). In a state where the positive electrode tab group 280 is 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 (S4 process). 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.

[0135] 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 on one side relative to the center of the first electrode body 201 and the second electrode body 202. This allows the current collectors to be short and compact.

[0136] In addition, the current collector 410, the current collector 420, and the current collector 430 are not limited to this configuration. The current collector 410, the current collector 420, and the current collector 430 may 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 negative electrode tab group 220, the positive electrode tab group 250, the negative electrode tab group 270, and the positive electrode tab group 280 are arranged at the center of the first electrode body 201 and the second electrode body 202, respectively, corresponding to the current collector 410, the current collector 420, and the current collector 430.

[0137] In addition, the order of the steps of joining the collector 410, the collector 420, and the collector 430 to the first electrode body 201 and the second electrode body 202, respectively, is not limited to the above content, and the order may be changed. The steps of joining the collector 410 and the collector 430 to the first electrode body 201 and the second electrode body 202, respectively, 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 collector 420 to the first electrode body 201 and the second electrode body 202.

[0138] Next, after the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420, the first electrode body 201 and the second electrode body 202 are connected in the thickness direction (in the same direction as the thickness of the first electrode body 201 and the second electrode body 202). Fig.14 as well as Fig.15 The positive electrode tab group 250 and the positive electrode tab group 280 are bent in a direction perpendicular to the DR1 direction of the electrode body 202 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 brought together.

[0139] The so-called "overlapping the first electrode body and the second electrode body" may be overlapping the first electrode body and the second electrode body directly, 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 belt or the like, or may not be fixed. Furthermore, the first electrode body, the current collector, and the second electrode body may not be arranged on a straight line in the first direction (DR1 direction), or the first electrode body or the second electrode body may be inclined relative to the first direction (DR1 direction) relative to the current collector.

[0140] The positive electrode tab group 250 and the positive electrode tab group 280 are bent so that their end portions face each other. In addition, the negative electrode tab group 220 and the negative electrode tab group 270 are also bent so that their end portions face each other.

[0141] Fig.13 as well as Fig.16 2 is a perspective view showing a state where a bracket and a separator are installed on an electrode body. Fig.16 As shown, next, the separator 600 and the insulating sheet 700 are assembled on the electrode body 200 (step S6 ).

[0142] In addition, the insulating sheet 700 does not necessarily have to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers about 50% or more of the outer surface of the electrode body, and more preferably covers about 70% or more of the area. The insulating sheet 700 preferably covers the entirety of four of the six surfaces of the roughly rectangular (flat) electrode body 200, except for at least two surfaces on which the negative electrode tab group 220 and the positive electrode tab group 250 are formed.

[0143] Fig.17 It is a perspective view showing a state where the sealing plate 120 is attached to the current collector on the negative electrode side. Fig.18 yes Fig.17 XVIII-XVIII cross-sectional view of the electrode body and the current collector shown. Fig.19 as well as Fig. 20 These are first and second perspective views showing the form of the spacer 600 .

[0144] like Fig.19 as well as Fig. 20 As shown in the figure, the spacer 600 is made 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 connecting the side walls of one side of each of the first component 612 and the second component 614. On the inner side of the connecting wall 611, a convex portion 616 is provided so as to extend between the first component 612 and the second component 614 (along the Z direction).

[0145] The first member 612 includes a first plate portion 617 provided to connect three walls. A plurality of first elliptical through holes 617s are provided in the first plate portion 617. The shape and number of the first through holes 617s can be appropriately selected and are not limited to the shape and number shown in the figure.

[0146] The second member 614 includes a second plate portion 618 provided 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 can be appropriately selected and are not limited to the shape and number shown in the figure.

[0147] The first plate portion 617 and the second plate portion 618 are located on the end face side of the electrode body. The plate portion may or may not abut against the end face of the electrode body. In the case of not abutting, the shortest distance is preferably within 2 mm, more preferably within 1 mm. Furthermore, by providing the first through hole 617s and the second through hole 618s, Figure 1 When the secondary battery 1 shown is placed with the Z direction facing upward (the direction in which the openings 113 (first opening) and openings 114 (second opening) at both ends of the shell body 110 are arranged on the left and right), even if the electrolyte that is pressed out of the electrode body to the outside of the electrode body during charging (generally when the electrode plates expand) flows out of the said portion, it is easy to return to the electrode body during discharging (generally when the electrode plates shrink).

[0148] like Fig.13 , Fig.17 as well as Fig.18As shown, after the negative electrode tab group 220 is joined to the current collector 410, the negative electrode tab group 270 is joined to the current collector 430, and the first electrode body 201 and the second electrode body 202 are overlapped, 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). Alternatively, the step S7 may be performed before the step S6.

[0149] Specifically, the negative electrode tab group 220 and the negative electrode tab group 270 are bent so that the terminal ends 222 and 272 face each other.

[0150] The negative terminal 301 and the current collector 440 are mounted on 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. In addition, the plate-like member 303 may be connected to the negative terminal 301 at any time. The current collector 440 is joined to the current collector 410 and the current collector 430 by laser welding between the sealing plate 120 and the insulating sheet 700.

[0151] Fig.21 2 is a perspective view showing a state where the electrode body is inserted into the housing body. Fig.13 as well as Fig.21 As shown in the figure, after the first electrode body 201 and the second electrode body 202 are overlapped, the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 from the opening 113 with the collector 420 side as the front (S8 process). At this time, 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 toward the negative electrode tab 230 side compared to the end of the positive electrode active material layer 242, and the details are described later.

[0152] The negative electrode tab group 220 and the negative electrode tab group 270 are bent by bringing the sealing plate 120 and the main body of the electrode body 200 (the first electrode body 201 and the second electrode body 202) close to each other. In addition, it is preferred that the sealing plate 120 and the case body 110 are brought close to each other by bringing the sealing plate 120 and the main body of the electrode body 200 disposed in the case body 110 close to each other. Fig.11 As shown, the negative electrode tab group 220 and the negative electrode tab group 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.

[0153] After the sealing plate 120 is brought into contact with the housing body 110, the sealing plate 120 is temporarily joined to the housing body 110. By temporarily joining, the sealing plate 120 is partially joined to the opening 113 of the housing body 110. Thus, the sealing plate 120 is positioned relative to the housing body 110.

[0154] When the electrode body 200 is inserted into the case body 110, the electrode body 200 may be pulled from the current collector 420 side or pressed from the current collectors 410 and 430 sides. When the electrode body 200 is pressed from the current collectors 410 and 430 sides, the negative electrode tab group 220 and the negative electrode tab group 270 can be bent simultaneously.

[0155] Fig. 22 It is a perspective view showing a state where a sealing plate 130 is attached to the current collector on the positive electrode side. Fig.23 yes Fig. 22 The electrode body and the collector are shown in the XXIII-XXIII cross-sectional view. Fig.23 In the embodiment, the shell body 110 is omitted.

[0156] like Fig.13 , Fig.21 as well as Fig. 22 As shown, after the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 , the current collector 420 and the positive electrode terminal 302 are electrically connected (step S9 ).

[0157] Specifically, the positive terminal 302 and the current collector 450 are mounted on 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. In addition, the plate-like member 304 may be connected to the positive terminal 302 at any time.

[0158] like Fig.23 As shown, the positive electrode tab group 250 and the positive electrode tab group 280 connected to the current collector 420 are bent so that the end portions 252 and 282 face each other. Fig.23 From the state shown, the sealing plate 130 is brought into contact with the case body 110. At this time, the positive electrode tab group 250 and the positive electrode tab group 280 are bent by bringing the sealing plate 130 and the main body of the electrode body 200 close to each other. Fig.12 As shown, the positive electrode tab group 250 and the positive electrode tab group 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.

[0159] After the sealing plate 130 is brought into contact with the housing body 110, the sealing plate 130 is temporarily welded to the housing body 110. By temporarily joining, the sealing plate 130 is partially joined to the opening 114 of the housing body 110. Thus, the sealing plate 130 is positioned relative to the housing body 110.

[0160] Fig.24 1 is a perspective view showing the structure of the secondary battery 1. Fig.13 as well as Fig.24 As shown, 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. Thus, the first electrode body 201 and the second electrode body 202 are accommodated in the case 100.

[0161] 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 the moisture in the shell 100. And, the electrolyte is injected into the interior of the shell 100 from the injection hole 134. When injecting the electrolyte, the sealing plate 130 is facing upward, the sealing plate 120 is facing downward, the shell 100 is tilted, and the electrolyte is injected into the interior of the shell 100 from the injection hole 134 of the sealing plate 130. Then, exhaust charging is performed. During exhaust charging, the injection hole 134 can also be temporarily sealed. Then, the injection hole 134 is sealed, and the secondary battery 1 is completed.

[0162] In addition, the order of the insertion process of the electrode body 200 and the connection process of the current collectors is not limited to the above example. For example, only a part of the electrode body 200 can be inserted into the shell body 110 in a manner such that the end of the opening 113 side in the negative electrode active material layer 212 (the second electrode active material layer) is arranged outside the shell body 110 (the first process), and then the negative terminal 301 (the first electrode terminal) provided on the sealing plate 120 (the first sealing plate) and the negative electrode tab group 220, 270 (the first electrode tab) are electrically connected, and then, the electrode body 200 is inserted into the shell body 110 until the end of the opening 113 side in the negative electrode active material layer 212 is arranged inside the shell body 110 (the second process). That is, the negative terminal 301 and the electrode body 200 can be electrically connected in the middle of the insertion process of the electrode body 200 into the shell body 110.

[0163] In this embodiment, by providing the negative electrode tab group 220 and the positive electrode tab group 250 in the first electrode body 201 and providing the negative electrode tab group 270 and the positive electrode tab group 280 in the second electrode body 202, it is possible to have separate electrode tabs in the first electrode body 201 and the second electrode body 202. According to this structure, the electrode tabs gathered together are formed by the first electrode body 201 and the second electrode body 202, and the electrode tabs can be shortened compared to the case where the electrode tabs are bent. As a result, the volume occupied by the electrode tabs can be reduced, and thus the energy density of the secondary battery 1 can be improved. In addition, in the structure in which separate electrode tabs are provided in the first electrode body 201 and the second electrode body 202, the electrode tabs are easy to bend compared to the case in which the electrode tabs are gathered together by the first electrode body 201 and the second electrode body 202, so that the electrode tabs are easy to be joined to the collector, and the secondary battery can be stably manufactured. 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 improved.

[0164] (Structure of End of Electrode Body 200)

[0165] Reference Figure 25 to Figure 27 The structure of the end portion of the electrode body 200 will be described. Fig.25 is a cross-sectional view taken along a plane including the Z axis in a state where the electrode body is inserted into the housing body. Fig.26 2 is a cross-sectional view showing a schematic structure of the electrode body 200 after stacking, taken along a plane including the Z axis. Fig. 27 2 is a cross-sectional view taken along a plane including the Z axis, showing a schematic structure of the electrode body 200 after the secondary battery is completed. Figure 25 to Figure 27 In the drawings, the current collector, the case body, and the sealing plate are omitted as appropriate.

[0166] Reference Fig.25 In the main body of the electrode body 200, at the end portion on the positive electrode tab 260 side, the positive electrode protection layer 243 protrudes toward the positive electrode tab 260 side compared with the end portion of the negative electrode active material layer 212 (X1 in the figure), and at the end portion on the negative electrode tab 230 side, the negative electrode active material layer 212 protrudes toward the negative electrode tab 230 side compared with the end portion of the positive electrode active material layer 242 (Y1 in the figure).

[0167] The separator 800 has a positive electrode side protruding region 800x (the protruding length is X2 in the figure) protruding toward the positive electrode tab 260 side compared with the end of the positive electrode protection layer 243 at the end of the positive electrode tab 260 side, and has a negative electrode side protruding region 800y (the protruding length is Y2 in the figure) protruding toward the negative electrode tab 230 side compared with the end of the negative electrode active material layer 212 at the end of the negative electrode tab 230 side. The protruding length (Y2) of the negative electrode side protruding region 800y is set to be greater than the protruding length (X2) of the positive electrode side protruding region 800x (Y2>X2).

[0168] In the above Fig.21 In the state where the electrode body is inserted into the case body as shown, the first plate portion 617 and the second plate portion 618 of the spacer 600 abut against the end surface of the electrode body, more specifically, the negative-side protruding region 800y, while the electrode body 200 is pressed into the interior of the case body 110 by the external force F applied to the sealing plate 120. At this time, at least a portion of the area of ​​the negative-side protruding region 800y abutting against the spacer 600 is crushed, and the area of ​​the negative-side protruding region 800y not abutting against the spacer 600 remains in its original state, and the electrode body 200 is pressed into the interior of the case body 110.

[0169] Here, refer to Fig.26 The specific dimensional relationship of the electrode body 200 before being inserted into the case body is described. On the positive electrode tab 260 side, the protruding length X1 of the positive electrode protection layer 243 relative to the negative electrode active material layer 212 is about 1.0 mm. The protruding length X2 of the positive electrode side protruding area 800x of the separator 800 is about 2.5 mm. In addition, the protruding length X2 of the positive electrode side protruding area 800x can be 2 mm or more.

[0170] On the negative electrode tab 230 side, the protrusion length Y2 of the negative electrode side protrusion region 800y is about 3.0 mm. Alternatively, the protrusion length Y2 of the negative electrode side protrusion region 800y may be 2 mm or more.

[0171] Furthermore, before the electrode body 200 is inserted into the case body, a protrusion dimension Tx of the positive electrode tab 260 from the end of the positive electrode protection layer 243 and a protrusion dimension Ty of the negative electrode tab 230 from the end of the negative electrode active material layer 212 are set to be substantially the same.

[0172] Next, refer to Fig. 27 The specific dimensional relationship of the electrode body 200 after being inserted into the case body will be described. The configuration of the negative electrode tab 230 side after the electrode body 200 is inserted into the case body is as follows: Fig.11 In the state shown, the structure of the positive electrode tab 260 side becomes Fig.12 Status shown.

[0173] On the positive electrode tab 260 side, the positive electrode side protruding region 800x of the separator 800 is in a state of being crushed in the region abutting against the first plate portion 617 and the second plate portion 618 of the separator 600. In this case, the length (X3 in the figure) of the positive electrode side protruding region 800x being crushed is less than about 1.5 mm. Therefore, the width of the positive electrode side protruding region 800x in the electrode body 200 after being inserted into the case body is about 1.0 mm to 2.5 mm.

[0174] On the other hand, the negative electrode side protruding region 800y of the separator 800 also becomes a state where the region abutting against the first plate portion 617 and the second plate portion 618 of the separator 600 is crushed. In this case, the length (Y3 in the figure) by which the negative electrode side protruding region 800y is crushed is larger than the positive electrode side protruding region 800x side and exceeds a dimension of about 1.5 mm. Therefore, the width of the negative electrode side protruding region 800y in the electrode body 200 after being inserted into the shell body is about 0.5 mm to 2.5 mm. This is because, when the electrode body is inserted into the shell body, the first plate portion 617 and the second plate portion 618 of the separator 600 abut against the negative electrode side protruding region 800y, while the electrode body 200 is pressed into the interior of the shell body 110 by the external force F applied to the sealing plate 120.

[0175] In this way, the diaphragm 800 is in a state of being collapsed in the areas (a total of 4 places) that abut against the first plate portion 617 and the second plate portion 618 of the spacer 600 arranged at both ends. By setting the protruding length of the negative electrode side protruding area 800y to be larger than the protruding length of the positive electrode side protruding area 800x, the negative electrode side protruding area 800y of the diaphragm 800 becomes a buffer, which can suppress damage to the negative end portion of the electrode body on the negative electrode tab 230 side when the electrode body 200 is inserted into the shell body.

[0176] Furthermore, when the electrolyte is injected into the interior of the shell 100 from the injection hole 134, when the shell 100 is erected in a manner such that the injection hole 134 is upward (when the X direction is the up and down direction), a load is applied to the negative electrode side protruding area 800y portion on the negative electrode tab 230 side to bend the negative electrode side protruding area 800y portion, which can suppress the electrolyte from flowing out from the end of the electrode body during charging and discharging, and can also suppress Li precipitation near the negative electrode tab 230.

[0177] Furthermore, it is assumed that after the secondary battery 1 is manufactured, 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 separator 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 separator 600, the volume of the space 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 volume of the space from the end of the positive electrode protective layer 243 on the positive electrode tab 260 side to the sealing plate 130. Specifically, it is assumed 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 shell body are set to approximately the same size, and after the secondary battery 1 is manufactured, Fig.12 The distance Hy (from the base of the tab to the current collector) shown on the positive electrode side is greater than Fig.11 (Negative electrode side) is the distance Hx (the distance from the base of the tab to the current collector).

[0178] (Positive plate and negative plate)

[0179] Hereinafter, examples of the configurations of the positive electrode plate and the negative electrode plate that are suitable in the secondary battery 1 according to the present embodiment will be described, but the scope of the present technology is not limited thereto.

[0180] In the positive electrode plate, the positive electrode core 241 is made of, for example, a metal foil containing aluminum, aluminum alloy, etc. 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.

[0181] The positive electrode active material layer 242 contains a positive electrode active material. In addition to the positive electrode active material, the positive electrode active material layer 242 may also contain a binder (PVDF, etc.) and a conductive member (carbon material, etc.). The positive electrode active material is preferably a lithium transition metal composite oxide, etc. The positive electrode active material may also be a mixture of multiple substances.

[0182] The thickness of the positive electrode active material layer 242 is, for example, preferably about 30 μm or more, more preferably about 40 μm or more, and further preferably about 50 μm or more. The thickness of the positive electrode active material layer 242 is, for example, preferably about 500 μm or less, and more preferably about 300 μm or less.

[0183] The positive electrode protection layer 243 is a layer with a greater resistance than the positive electrode active material layer 242. The positive electrode protection layer 243 contains substantially no positive electrode active material or contains only a trace amount. For example, the mass of the positive electrode active material relative to the total mass of the positive electrode protection layer 243 is about 5% or less, preferably about 1% or less.

[0184] The positive electrode protective layer 243 preferably contains inorganic particles (e.g., alumina, boehmite, etc.). The positive electrode protective layer 243 preferably contains inorganic particles and a binder. The positive electrode protective layer 243 preferably contains about 50% by mass or more of inorganic particles. The positive electrode protective layer 243 can be an insulating resin layer or a conductive substance containing a carbon material.

[0185] Preferably, the positive electrode protection layer 243 is formed on the positive electrode core 241 along the end of the portion where the positive electrode active material layer 242 is formed. Preferably, the positive electrode protection layer 243 is arranged so as to face the end of the negative electrode active material layer 212 via a separator (insulating sheet). Thus, short circuits between the positive electrode core 241 and the end of the negative electrode active material layer 212 can be suppressed.

[0186] The thickness of the positive electrode protection layer 243 is preferably thinner than the thickness of the positive electrode active material layer 242. The thickness of the positive electrode protection layer 243 is preferably about 10 μm or more, more preferably about 20 μm or more, and further preferably about 30 μm or more. The thickness of the positive electrode protection layer 243 is, for example, preferably about 200 μm or less, more preferably about 100 μm or less, and further preferably about 50 μm or less.

[0187] In the negative electrode plate, the negative electrode core 211 is preferably made of a metal such as copper or a copper alloy, and more preferably made of a metal foil.

[0188] The thickness of the negative electrode core 211 is, for example, about 3 μm or more, and more preferably about 5 μm or more. The thickness of the negative electrode core 211 is, for example, about 30 μm or less, and more preferably about 20 μm or less.

[0189] The negative electrode active material layer 212 contains a negative electrode active material. In addition to the negative electrode active material, the negative electrode active material layer 212 may also contain a binder (SBR, CMC, etc.) and a conductive member (carbon material, etc.). The negative electrode active material is preferably a carbon material such as graphite, a silicon material such as SiO, SiC, etc. The negative electrode active material may also be a mixture of multiple substances.

[0190] The thickness of the negative electrode active material layer 212 is, for example, preferably about 50 μm or more, more preferably about 60 μm or more, and further preferably about 70 μm or more. The thickness of the negative electrode active material layer 212 is, for example, preferably about 500 μm or less, and more preferably about 300 μm or less.

[0191] As described above, the separator 800 is greatly crushed on the negative electrode tab 230 side, so it is preferable to have a certain degree of strength. For example, it is preferable to use a tensile strength of 500 kgf / cm in the crushing direction, that is, the TD direction. 2 As the material, a single layer film or a laminated film of polyethylene or polypropylene with a thickness of about 5 μm to 20 μm can be listed. In addition, an insulating heat-resistant layer containing ceramics such as alumina, boehmite, magnesium oxide, and an adhesive (PVDF, etc.) can also be formed on one or both sides of the diaphragm surface.

[0192] (Other forms of electrode bodies)

[0193] Reference Figures 28 to 30 Other aspects of the electrode body will be described. Figure 29 to Figure 30 2 is a schematic cross-sectional view showing various forms of the electrode body. In addition, a separator fixing band 900 is shown in the figure.

[0194] In the above-mentioned embodiment, as the electrode body, Fig.28 As shown in FIG. 1 , the case where a so-called leaf-shaped laminated electrode body is used in which an independent separator 800 is arranged between the negative electrode plate 210 and the positive electrode plate 240 is described, but the form of the electrode body is not limited to this. Fig.29 As shown in FIG. 1 , a so-called folded laminated electrode body is configured to reciprocate between the negative electrode plate 210 and the positive electrode plate 240 using a separator 800. Fig.30 As shown, the separator 800 is disposed between the negative electrode plate 210 and the positive electrode plate 240 and the electrodes are wound around an axis.

[0195] In addition, in the above-mentioned embodiment, since the negative electrode tab 230 side of the separator 800 is expected to be crushed, when there is a separator extending in the thickness direction (Y direction) of the electrode body, there is a possibility that the crushing of the negative electrode tab 230 side is blocked. Therefore, in the order of the leaf type, the bent type and the winding type, the preferred crushing effect can be obtained.

[0196] On the other hand, it is believed that the rapid charging performance is higher through lamination than winding, and even during lamination, the bent type can obtain rigidity at the folded back parts of the upper and lower ends of the separator compared to the blade type, making it difficult to damage the electrode plate. Therefore, it is believed that it is suitable for the insertion process of the electrode body into the shell and the injection process of the electrolyte into the shell of this embodiment.

[0197] As described above, the technology disclosed herein can avoid the possibility of the electrode body being damaged when the electrode body is inserted into the battery case and / or when the case is erected during liquid injection. As a result, a secondary battery with high energy density and high reliability and a method for manufacturing the same can be provided.

[0198] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A secondary battery, wherein: The secondary battery has: an electrode body in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween; and a shell that accommodates the electrode body; The housing includes: a housing body having a first opening at one end and a second opening at the other end; a first sealing plate sealing the first opening; and a second sealing plate 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 portion on the second sealing plate side. The negative electrode plate has a negative electrode tab at an end portion on the first sealing plate side. The positive electrode plate comprises: a positive electrode core; a positive electrode active material layer formed on the positive electrode core; and a positive electrode protective 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 relative to the positive electrode active material layer. The negative electrode plate comprises: 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 at the end portion on the positive electrode tab side that protrudes toward the positive electrode tab side compared to the end portion of the positive electrode protection layer, and has a negative electrode side protruding region at the end portion on the negative electrode tab side that protrudes toward the negative electrode tab side compared to the end portion of the negative electrode active material layer, The separator has a region that is crushed by the first separator in the negative electrode-side protruding region.

2. The secondary battery according to claim 1, wherein The separator has a region in the positive electrode side protruding region that is collapsed by the second separator. The collapsed width of the negative electrode side protruding region is greater than the collapsed width of the positive electrode side protruding region.

3. The secondary battery according to claim 1, wherein In the separator, the width of the negative electrode side protruding region is larger than the width of the positive electrode side protruding region.

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

5. A method for manufacturing a secondary battery, wherein: The method for manufacturing the secondary battery comprises: a step of manufacturing an electrode body in which a positive electrode plate and a negative electrode plate are stacked with a separator therebetween; and a step of housing the electrode assembly in a casing, The housing includes: a housing body having a first opening at one end and a second opening at the other end; a first sealing plate sealing the first opening; and a second sealing plate 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 comprises: a main body; a positive electrode tab located on the second sealing plate side relative to the main body and provided on the positive electrode plate; and a negative electrode tab located on the first sealing plate side relative to the main body and provided on the negative electrode plate. The positive electrode plate comprises: a positive electrode core; a positive electrode active material layer formed on the positive electrode core; and a positive electrode protective 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 relative to the positive electrode active material layer. The negative electrode plate comprises: a negative electrode core; and a negative electrode active material layer formed on the negative electrode core. In the main body of the electrode body, at an end portion on the positive electrode tab side, the positive electrode protection layer protrudes toward the positive electrode tab side more than the end portion of the negative electrode active material layer, and at an end portion on the negative electrode tab side, the negative electrode active material layer protrudes toward the negative electrode tab side more than the end portion of the positive electrode active material layer, The separator has a positive electrode side protruding region at the end portion on the positive electrode tab side that protrudes toward the positive electrode tab side compared to the end portion of the positive electrode protection layer, and has a negative electrode side protruding region at the end portion on the negative electrode tab side that protrudes toward the negative electrode tab side compared to the end portion 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.

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

7. The method for manufacturing a secondary battery according to claim 5, wherein: The step of inserting the electrode body into the case body from the first opening includes 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 a region abutting against the separator.

8. The method for manufacturing a secondary battery according to claim 5, wherein: The electrode body is inserted into the case body from an end portion of the electrode body on which the positive electrode tab is arranged.

9. The method for manufacturing a secondary battery according to claim 8, wherein: After the negative electrode tab and the first sealing plate are connected, the electrode assembly is inserted into the case body.

10. The method for manufacturing a secondary battery according to claim 8, wherein: After the electrode body is inserted into the case body, the positive electrode tab and the second sealing plate are connected.

11. The method for manufacturing a secondary battery according to claim 5, wherein: The negative electrode tab is electrically connected to the negative electrode terminal attached to the first sealing plate via a negative electrode current collector.

12. The method for manufacturing a secondary battery according to claim 5, wherein: The positive electrode tab is electrically connected to the positive electrode terminal attached to the second sealing plate via a positive electrode current collector.

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