Battery manufacturing method

Abstract

This disclosure provides a method for manufacturing a battery that can suppress cracking of the electrode active material layer on the opposite side of the gap between bipolar electrode stacks. [Solution] The present disclosure's method for manufacturing a battery includes conveying a heated long sheet-like bipolar electrode stack 100 on a conveyor roller 20. The present disclosure's method further includes the following: the temperature drop of the bipolar electrode stack when it passes the conveyor roller is 30°C or more; the bipolar electrode stack is pressed with a pressing roller 30 before it passes the conveyor roller; the temperature drop of the bipolar electrode stack when it passes the pressing roller is less than 30°C; the pressing roller has a protrusion 31 at a position that overlaps with the gap 131 of the bipolar electrode stack or the opposite side thereof; and a transverse tensile stress is applied to the gap when the bipolar electrode stack passes the pressing roller.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a battery.

Background Art

[0002] As disclosed in Patent Documents 1 and 6, techniques for suppressing the occurrence of wrinkles in an electrode laminate conveyed by rollers are known.

[0003] Patent Documents 2 to 5 disclose electrode laminates having gap portions formed in the in-plane of the electrode active material layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present inventors have found that in the manufacture of a bipolar electrode laminate having a gap portion formed in the in-plane of one electrode active material layer, cracks are likely to occur in the other electrode active material layer on the opposite side of the gap portion during roller conveyance.

[0006] An object of the present disclosure is to provide a method for manufacturing a battery that can suppress such cracks in the electrode active material layer. [Means for solving the problem]

[0007] The Disclosing Party has found that the above-mentioned problems can be solved by the following means. <Aspect 1> A method for manufacturing a battery, comprising conveying a heated, long sheet-like bipolar electrode stack using a conveyor roller, The bipolar electrode laminate comprises a first electrode active material layer, a current collector layer, and a second electrode active material layer in this order. The first electrode active material layer is composed of a plurality of island-like portions extending in the transport direction, and there is at least one gap between the plurality of island-like portions that extends in the transport direction. When the bipolar electrode stack passes through the transport roller, the temperature drop of the bipolar electrode stack is 30°C or more. The method further includes pressing the bipolar electrode stack with a pressing roller before the bipolar electrode stack passes through the transport roller, When the bipolar electrode stack passes through the pressing roller, the temperature drop of the bipolar electrode stack is less than 30°C. The pressing roller has a protrusion at a position overlapping with the gap or the opposite side thereof, thereby causing transverse tensile stress to be applied to the gap when the bipolar electrode laminate passes through the pressing roller. Battery manufacturing method. <Aspect 2> The method according to embodiment 1, wherein the width of the protrusion is less than or equal to the width of the gap. <Aspect 3> The method according to embodiment 1 or 2, wherein the cross-sectional shape of the convex portion is a rounded quadrilateral shape. <Aspect 4> The method according to any one of embodiments 1 to 3, further comprising drying the first electrode active material layer and the second electrode active material layer by laser heating before the pressing. <Aspect 5> The method according to embodiment 4, further comprising pressing the bipolar electrode laminate before the drying.

Advantages of the Invention

[0008] According to the method of the present disclosure for manufacturing a battery, the occurrence of cracks in the electrode active material layer as described above can be suppressed.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of the method of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of a bipolar electrode laminate according to the method of the present disclosure. [Figure 3] FIG. 3 is a schematic top view showing an example of the method of the present disclosure. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an example of the method of the present disclosure.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments and can be variously modified and implemented within the scope of the gist of the disclosure.

[0011] 《Method for Manufacturing a Battery》 The method of the present disclosure for manufacturing a battery includes roller-conveying a heated long sheet-like bipolar electrode laminate with conveying rollers. In the method of the present disclosure, the bipolar electrode laminate has a first electrode active material layer, a current collector layer, and a second electrode active material layer in this order, the first electrode active material layer is composed of a plurality of island-like portions extending in the conveying direction, and there is at least one gap portion extending in the conveying direction between the plurality of island-like portions. When the bipolar electrode laminate passes through the conveying rollers, the temperature drop of the bipolar electrode laminate is 30°C or more. Before the bipolar electrode laminate passes through the conveying rollers, the method further includes pressing the bipolar electrode laminate with pressing rollers. When the bipolar electrode laminate passes through the pressing rollers, the temperature drop of the bipolar electrode laminate is less than 30°C. The pressing rollers have convex portions at positions overlapping the gap portion or the opposite side surface thereof, so that when the bipolar electrode laminate passes through the pressing rollers, transverse tensile stress is applied to the gap portion.

[0012] As described above, the present inventors have found that in the manufacture of a bipolar electrode laminate having a gap portion formed in the plane of one electrode active material layer (the first electrode active material layer), when roller-conveying, cracks are likely to occur in the other electrode active material layer (the second electrode active material layer) on the opposite side surface of this gap portion.

[0013] The present inventors considered that one of the causes of the cracks in the second electrode active material layer on the opposite side surface of this gap portion is due to thermal shrinkage. That is, when roller-conveying a heated long sheet-like bipolar electrode laminate with conveying rollers, it is considered that the temperature of the bipolar electrode laminate is lowered by the conveying rollers. The gap portion in the bipolar electrode laminate has less rigidity compared to other portions, and therefore, it is considered that wrinkles due to thermal shrinkage occur in the gap portion. It is considered that the wrinkles generated in this way interfere with the conveying rollers, causing cracks in the second electrode active material layer on the opposite side surface of the gap portion.

[0014] In response to this, the Disclosing Party has found that even if the temperature of the bipolar electrode stack is lowered by the transport roller, the bipolar electrode stack is further pressed by a pressing roller before passing through the transport roller, and the temperature drop of the bipolar electrode stack when it passes through the pressing roller is relatively small, and the pressing roller has a protrusion at a position that overlaps with the gap or the opposite side thereof, thereby applying transverse tensile stress to the gap when the bipolar electrode stack passes through the pressing roller, thereby suppressing the occurrence of cracks in the second electrode active material layer on the opposite side of the gap. The reason for this is presumed to be as follows: When passing through the pressure roller, the temperature drop of the bipolar electrode laminate is relatively small, and therefore thermal contraction in the gaps can be made less likely; and Because the gap is stretched in advance by the pressure roller, the thermal contraction in the gap when passing through the conveyor roller can be offset, thereby suppressing the formation of wrinkles. This is likely the reason.

[0015] The method for manufacturing electrodes according to this disclosure will be described below with reference to the drawings. Note that the dimensions in the drawings do not reflect the actual dimensions.

[0016] <Roller transport> As illustrated in Figure 1, the method of this disclosure includes conveying a heated long sheet-like bipolar electrode laminate 100 using a conveyor roller 20. Figure 1 is a schematic diagram illustrating how the bipolar electrode laminate is wound onto a winding reel 42 after being heated (dried) by a laser irradiation device 10 and conveyed by the conveyor roller 20 from an unwinding reel 41.

[0017] The heating temperature is not particularly limited, but may be, for example, 120°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, 190°C or higher, or 200°C or higher, and may be 300°C or lower, 290°C or lower, 280°C or lower, 270°C or lower, 260°C or lower, or 250°C or lower. When the heating temperature is within the above range, it is considered that the temperature of the bipolar electrode laminate 100 is easily lowered by the conveyor rollers 20 when the bipolar electrode laminate 100 is conveyed by the conveyor rollers 20. Based on this assumption, applying the method of this disclosure to a bipolar electrode laminate heated at a temperature within the above range is particularly effective.

[0018] As illustrated in Figure 2, in the method of this disclosure, the bipolar electrode stack comprises a first electrode active material layer 110, a current collector layer 130, and a second electrode active material layer 120 in that order.

[0019] As illustrated in Figures 2 and 3, in the method of this disclosure, the first electrode active material layer 110 is composed of a plurality of island-like portions 111 extending in the transport direction, and at least one gap portion 131 extending in the transport direction exists between the plurality of island-like portions. The transport direction is indicated by the arrow in Figure 3.

[0020] The number of island-like portions 111 and gap portions 131 is not particularly limited. For example, if the number of gap portions 131 is n, the number of island-like portions may be n+1. In this case, n is not particularly limited, but may be 1 or more, 2 or more, 3 or more, 5 or more, 7 or more, 9 or more, or 10 or more, and may be 30 or less, 25 or less, 20 or less, or 15 or less.

[0021] The gap 131 may extend over the entire bipolar electrode stack 100 in the transport direction of the bipolar electrode stack 100, or it may extend over a part of the bipolar electrode stack 100.

[0022] The first electrode active material layer 110, which is composed of multiple island-like portions 111, may be a positive electrode active material layer or a negative electrode active material layer, and may be particularly a positive electrode active material layer. The second electrode active material layer 120 may be a positive electrode active material layer or a negative electrode active material layer, and may be particularly a negative electrode active material layer.

[0023] In the method of this disclosure, the temperature drop of the bipolar electrode stack 100 when the bipolar electrode stack passes through the transport roller 20 is 30°C or more.

[0024] The temperature drop of the bipolar electrode stack 100 may occur because the temperature of the transport roller 20 is lower than the temperature of the heated bipolar electrode stack 100.

[0025] The temperature drop of the bipolar electrode stack 100 may be 40°C or higher, 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, or 100°C or higher, and may be 150°C or lower, 130°C or lower, or 110°C or lower. When the temperature drop of the bipolar electrode stack 100 is within the above range, thermal shrinkage is likely to occur in the gaps 131 of the bipolar electrode stack 100, and therefore, there is great significance in applying the method of this disclosure.

[0026] The temperature of the bipolar electrode stack may be monitored by a thermometer, such as a temperature sensor. The thermometer may be a non-contact type infrared thermometer.

[0027] As illustrated in Figure 1, the method of this disclosure further includes pressing the bipolar electrode stack 100 with a pressing roller 30 before the bipolar electrode stack 100 passes through the transport roller 20, and the temperature drop of the bipolar electrode stack 100 when it passes through the pressing roller 30 is less than 30°C. That is, the temperature drop of the bipolar electrode stack 100 is relatively small when it passes through the pressing roller 30. By having such a configuration, it is possible to suppress thermal shrinkage in the gap 131 of the bipolar electrode stack 100 when it passes through the pressing roller 30.

[0028] In order to ensure that the temperature drop of the bipolar electrode laminate 100 when it passes over the pressing roller 30 is less than 30°C, the pressing roller 30 can be a roller whose surface is made of an insulating material, a temperature-adjustable roller, or the like.

[0029] The thermal insulation material is not particularly limited, as long as it can suppress heat transfer between the bipolar electrode laminate 100 and the pressure roller 30.

[0030] A temperature-adjustable roller may have, for example, a heating element. The heating element may be, for example, a heater.

[0031] The temperature drop of the bipolar electrode laminate 100 when it passes the pressing roller 30 may be 25°C or less, 20°C or less, 15°C or less, 10°C or less, 5°C or less, 3°C or less, or 1°C or less, and no temperature drop may occur at all. If this temperature drop is within the above range, the occurrence of cracks in the second electrode active material layer 120 on the opposite side of the gap 131 can be suppressed more effectively.

[0032] For example, when a temperature-controllable roller is used as the pressing roller 30, this temperature drop can be prevented by setting the temperature of the temperature-controllable roller to be higher than or equal to the temperature of the bipolar electrode stack 100. In this case, the temperature of the temperature-controllable roller can be appropriately set to prevent an excessive temperature rise in the bipolar electrode stack 100 when it passes over the pressing roller 30.

[0033] As illustrated in Figures 3 and 4, in the method of this disclosure, the pressing roller 30 has a protrusion 31 at a position overlapping with the gap 131 or the opposite side thereof, thereby applying transverse tensile stress to the gap 131 when the bipolar electrode laminate 100 passes over the pressing roller 30. This configuration makes it possible to suppress the occurrence of cracks in the second electrode active material 120 layer on the opposite side of the gap 131. In the embodiment shown in Figure 3, the bipolar electrode laminate 100 is pressed by the pressing roller 30 with the second electrode active material layer 120 side of the bipolar electrode laminate 100 in contact with the pressing roller 30, but in Figure 3, for illustrative purposes, the portion of the bipolar electrode laminate 100 that overlaps with the pressing roller 30 is omitted.

[0034] The position of the protrusion 31 on the pressing roller 30 is not particularly limited, as long as it overlaps with at least a portion of the gap 131 or its opposite side. For example, as illustrated in Figure 4, the position of the center of the protrusion 31 and the position of the center of the gap 131 may substantially coincide in the transverse direction of the gap 131.

[0035] As illustrated in Figures 3 and 4, in the method of this disclosure, the width of the protrusion 31 may be less than or equal to the width of the gap 131. By having such a configuration, it is possible to suppress the protrusion 31 from applying unnecessary tensile stress to parts of the bipolar electrode stack other than the gap. In this disclosure, "width" means the length of the gap 131 in the transverse direction.

[0036] The width of the protrusion 31 can be appropriately designed, taking into consideration the degree of wrinkles that may occur in the gap 131.

[0037] The width of the gap can be set appropriately, taking into consideration the desired battery capacity, etc.

[0038] The protrusion 31 may be formed on a part of the outer circumference of the pressing roller 30, or it may be formed over the entire outer circumference.

[0039] In the method disclosed herein, the shape of the protrusion 31 is not particularly limited. For example, the cross-sectional shape of the protrusion 31 may be a square or a rounded square. By having a rounded square cross-sectional shape for the protrusion 31, it is possible to suppress scratches on the bipolar electrode laminate 100. For example, by rounding (R) the corners of the protrusion 31, a protrusion 31 with a rounded square cross-sectional shape can be formed. In this case, the radius of the R chamfer may be 0.5 mm or more, 1.0 mm or more, 2.0 mm or more, or 3.0 mm or more, and may also be 10.0 mm or less, 7.0 mm or less, or 5.0 mm or less. As illustrated in Figure 4, the entire surface of the protrusion 31 may be a curved surface.

[0040] The material constituting the protrusion 31 is not particularly limited and may be the same material as the conveyor roller, or a different material. From the viewpoint of increasing the tensile stress applied to the gap and thereby more effectively suppressing cracking in the second electrode active material layer, it is preferable that this material be a relatively hard material. From the viewpoint of suppressing damage to the bipolar electrode laminate, it is preferable that this material be a relatively soft material.

[0041] Although Figure 3 illustrates an embodiment in which the second electrode active material layer 120 is arranged on the radially inner side of the pressing roller 30, i.e., on the side in contact with the pressing roller 30, in the method of this disclosure, the first electrode active material layer 110 may be arranged on the side in contact with the pressing roller 30.

[0042] In the method of this disclosure, the temperature of the bipolar electrode stack when it is being transported by rollers is not particularly limited, but may be 40°C or higher, 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, or 100°C or higher, and may be 150°C or lower, 140°C or lower, 130°C or lower, 120°C or lower, 110°C or lower, or 100°C or lower. When this temperature is within the above range, a temperature decrease in the bipolar electrode stack is likely to occur, and therefore, there is great significance in applying the method of this disclosure.

[0043] When the bipolar electrode stack 100 is conveyed by the conveyor rollers 20, the conveying direction of the bipolar electrode stack 100 may be changed by a predetermined angle or more. In this case, the length over which the bipolar electrode stack 100 can be in contact with the conveyor rollers 20 becomes longer, and therefore the temperature of the bipolar electrode stack 100 is more likely to decrease, making it highly significant to apply the method of this disclosure. The predetermined angle is not particularly limited, but for example, it may be 45° or more, 60° or more, 70° or more, 80° or more, 85° or more, or 90° or more, and may be 180° or less, 150° or less, 130° or less, 120° or less, 110° or less, 100° or less, 95° or less, or 90° or less.

[0044] <Drying> The method of this disclosure may further include drying the first electrode active material layer 110 and the second electrode active material layer 120 by laser heating before pressing. Laser heating allows for efficient heating of the bipolar electrode stack. Air blowing may be used in conjunction with laser heating. The air blowing may be hot air.

[0045] As illustrated in Figure 1, laser heating may be performed by the laser irradiation device 10. The laser heating and roller conveying may be performed continuously or discontinuously, as illustrated in Figure 1.

[0046] When drying the first electrode active material layer and the second electrode active material layer by laser heating, the laser irradiation target may be either the first or the second electrode active material layer. If the first electrode active material layer is the positive electrode active material layer, the first electrode active material layer may be irradiated with the laser and heated in particular.

[0047] <press> Although not shown in the figures, the method of this disclosure may further include pressing the bipolar electrode laminate 100 before drying.

[0048] If the second electrode active material layer 120 contains a binder, it is thought that the binder is compressed in the second electrode active material layer 120 after pressing, and therefore the flexibility is reduced. Based on this assumption, applying the method of this disclosure to a bipolar electrode laminate 100 that has been pressed is particularly effective.

[0049] The pressing method is not particularly limited, and a conventional method can be used.

[0050] The pressing pressure is not particularly limited and can be set as appropriate so that the density of the electrode active material layer reaches the desired value.

[0051] <Low-temperature drying> The method of this disclosure may further include drying the first and second electrode active material layers at a temperature lower than the temperature used in the laser heating drying described above, prior to pressing. The drying temperature in this step may be 80°C or higher, 90°C or higher, or 100°C or higher, and 140°C or lower, 130°C or lower, or 120°C or lower.

[0052] "battery" The battery of this disclosure is manufactured by the method of manufacturing a battery of this disclosure. In the battery of this disclosure, the occurrence of cracks in the second electrode active material layer on the opposite side of the gap 131 of the bipolar electrode stack 100 is suppressed.

[0053] The battery of this disclosure comprises a bipolar electrode stack 100 and optionally has an electrolyte layer.

[0054] The battery in this disclosure may be a liquid-based battery or a solid-state battery. In this disclosure, "solid-state battery" means a battery that uses at least a solid electrolyte as its electrolyte, and therefore a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as its electrolyte. Furthermore, the solid-state battery in this disclosure may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as its electrolyte.

[0055] The battery described herein may be a primary battery or a secondary battery. In particular, it may be a lithium-ion secondary battery.

[0056] The following describes each component that makes up a battery.

[0057] <Current collector layer> As the current collector layer, a known material used as the current collector layer for batteries can be employed. The current collector layer may be, for example, copper foil, copper alloy foil, nickel foil, aluminum foil, aluminum alloy foil, stainless steel foil, carbon sheet, etc.

[0058] The current collector layer may consist of two different types of current collector layers. In this case, each current collector layer may be bonded to each other via a conductive adhesive layer, or joined by pressing or the like. For example, the current collector layer on the negative electrode active material layer side may be copper foil, and the current collector layer on the positive electrode active material layer side may be aluminum foil.

[0059] The thickness of the current collector layer is not particularly limited, but may be 1 μm to 300 μm, 5 μm to 200 μm, or 10 μm to 100 μm. If the current collector layer has two types of current collector layers bonded to each other via a conductive adhesive layer, the total thickness of each layer may be within the above ranges.

[0060] The size of the current collector layer is not particularly limited and can be set appropriately, for example, taking into consideration the desired battery capacity.

[0061] The shape of the current collector layer in the battery obtained by the method of this disclosure is not particularly limited, but may be a rectangle or other quadrilateral, for example.

[0062] <First and second electrode active material layers> The first and second electrode active material layers contain electrode active material and may optionally contain a binder, conductive additive, and other components.

[0063] The electrode active material layer can be formed from the electrode composite slurry.

[0064] In this disclosure, "compound mixture" means a composition that can constitute an electrode active material layer, etc., either as is or by further containing other components. In this disclosure, "compound mixture slurry" means a slurry that includes a dispersion medium in addition to the "compound mixture," and can be applied and dried to form an electrode active material layer, etc.

[0065] The thickness of the electrode active material layer is not particularly limited. The thickness of the electrode active material layer may be 10 μm or more and 500 μm or less, 100 μm or more and 450 μm or less, or 200 μm or more and 400 μm or less.

[0066] The size of the electrode active material layer is not particularly limited and can be set appropriately, for example, taking into consideration the desired battery capacity.

[0067] The shapes of the first and second electrode active material layers in the battery obtained by the method of this disclosure are not particularly limited, but may be, for example, rectangular or other quadrilateral shapes.

[0068] (electrode active material) The electrode active material is not particularly limited. For example, in relation to this disclosure, if the first electrode active material layer is a positive electrode active material layer, the first electrode active material layer may contain a positive electrode active material. Also, for example, if the second electrode active material layer is a negative electrode active material layer, the second electrode active material layer may contain a negative electrode active material.

[0069] The positive electrode active material is not particularly limited as long as it has a noble potential compared to the negative electrode active material. When the bipolar electrode stack of this disclosure is a bipolar electrode stack for a lithium-ion secondary battery, the positive electrode active material may be, for example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), solid solution oxide (Li2MnO3-LiMO2 (M=Co, Ni, etc.)), lithium nickel manganese oxide (LiNi 1 / 2 Mn 1 / 2 O2), lithium nickel-cobalt-manganate (LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 Composite oxides such as O2, olivine-type lithium phosphate oxide (LiFePO4); conductive polymers such as polyaniline and polypyrrole; sulfide-based positive electrode active materials such as Li2S, CuS, Li-Cu-S compounds, TiS2, FeS, MoS2, Li-Mo-S compounds, Li-Ti-S compounds, and Li-VS compounds; materials using sulfur as an active material, such as sulfur-impregnated acetylene black, sulfur-impregnated porous carbon, and mixed powders of sulfur and carbon; etc. These positive electrode active materials may be used individually or in combination of two or more.

[0070] The content of positive electrode active material in the positive electrode mixture as an electrode mixture is not particularly limited, but may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more.

[0071] The shape of the positive electrode active material may be, for example, particulate.

[0072] The negative electrode active material is not particularly limited as long as it has a lower potential compared to the positive electrode active material. When the bipolar electrode stack of this disclosure is a bipolar electrode stack for a lithium-ion secondary battery, the negative electrode active material may be, for example, carbonaceous materials such as graphite (artificial graphite, natural graphite), resin carbon, carbon fiber, activated carbon, hard carbon, soft carbon; metallic materials mainly consisting of tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, aluminum alloys, etc.; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; Li4Ti5O 12 Examples include lithium titanium composite oxides such as Li-Si alloys, Li-Sn alloys, Li-Al alloys, Li-Ga alloys, Li-Mg alloys, and Li-In alloys; and lithium alloys such as Li-Si alloys, Li-Sn alloys, Li-Al alloys, Li-Ga alloys, Li-Mg alloys, and Li-In alloys. These negative electrode active materials may be used individually or in combination of two or more.

[0073] The content of the negative electrode active material in the negative electrode mixture as an electrode mixture is not particularly limited, but may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more.

[0074] The negative electrode active material may be in the form of particulate matter, for example.

[0075] (Binder) While not particularly limited, examples of binders include polyvinylidene fluoride (PVdF), polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamide-imide, polyvinyl alcohol, polyacrylonitrile, polyacrylic acid, polymethyl polyacrylate, polyethyl polyacrylate, polyhexyl polyacrylate, polymethacrylic acid, polymethyl polymethacrylate, polyethyl polymethacrylate, polyhexyl polymethacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, polyhexafluoropropylene, styrene-butadiene rubber, carboxymethylcellulose, and the like, especially when the battery of this disclosure is a lithium-ion secondary battery.

[0076] The binder content in the electrode mixture is not particularly limited and can be set appropriately according to the desired binding properties, etc.

[0077] (Conductive additive) The conductive additives are not particularly limited, but in the case of a lithium-ion secondary battery, examples include graphites such as natural graphite and artificial graphite; carbon blacks such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers such as carbon nanotubes and metal fibers; metal powders such as aluminum powder; conductive whiskers such as zinc oxide whiskers and conductive potassium titanate whiskers; conductive metal oxides such as titanium oxide; and organic conductive materials such as phenylene derivatives. These conductive additives may be used individually or in combination of two or more.

[0078] The content of the conductive additive in the electrode mixture is not particularly limited and can be set appropriately according to the desired conductivity, etc.

[0079] (Other ingredients) The electrode mixture may contain components other than those listed above. Examples of such components include solid electrolytes and dispersants. [Explanation of Symbols]

[0080] 100 Bipolar Electrode Stacks 110 First electrode active material layer 111 Island-shaped part 120 Second electrode active material layer 130 Current collector layer 131 Gap 10 Laser irradiation device 20 Conveyor rollers 30 Pressure rollers 31 Convex part

Claims

1. A method for manufacturing a battery, comprising conveying a heated, long sheet-like bipolar electrode stack using a conveyor roller, The bipolar electrode laminate comprises a first electrode active material layer, a current collector layer, and a second electrode active material layer in this order. The first electrode active material layer is composed of a plurality of island-like portions extending in the transport direction, and there is at least one gap between the plurality of island-like portions that extends in the transport direction. When the bipolar electrode stack passes through the transport roller, the temperature drop of the bipolar electrode stack is 30°C or more. The method further includes pressing the bipolar electrode stack with a pressing roller before the bipolar electrode stack passes through the transport roller, When the bipolar electrode stack passes through the pressing roller, the temperature drop of the bipolar electrode stack is less than 30°C. The pressing roller has a protrusion at a position overlapping with the gap or the opposite side thereof, thereby causing transverse tensile stress to be applied to the gap when the bipolar electrode laminate passes through the pressing roller. Battery manufacturing method.

2. The method according to claim 1, wherein the width of the protrusion is less than or equal to the width of the gap.

3. The method according to claim 1, wherein the cross-sectional shape of the convex portion is a rounded quadrilateral shape.

4. The method according to claim 1, further comprising drying the first electrode active material layer and the second electrode active material layer by laser heating before the pressing.

5. The method according to claim 4, further comprising pressing the bipolar electrode laminate before the drying.

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