Electrode and battery

Abstract

The invention provides an electrode and a battery. An electrode (positive electrode 100) has a collector layer (positive electrode collector layer 110), an active material layer (positive electrode active material layer 120), and an insulating layer (130). An active material layer (positive electrode active material layer 120) and a collector layer (positive electrode collector layer 110) are laminated and bonded, and the active material layer contains an active material (positive electrode active material 121). The insulating layer (130) is laminated and bonded to the active material layer (positive electrode active material layer (120)), and contains an insulating material (131) having insulating properties. The insulating material (131) has an average particle diameter (D50) of 0.5 [mu] m or more and 5.0 [mu] m or less. The porosity of the insulating layer (130) is 25% or more and 70% or less. The insulating layer (130) overlaps with the active material layer (positive electrode active material layer (120)) by 0.001% or more and 30% or less in the stacking direction (Z).

Description

Technical Field

[0001] The present invention relates to an electrode and a battery. Background Art

[0002] Conventionally, a technique has been known for an electrode in which an active material layer joined to a current collector layer is coated and joined with an insulating layer (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-061226 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] It is required to suppress an increase in the internal resistance of the battery.

[0008] Means for Solving the Problems

[0009] The electrode of the present invention has a current collector layer, an active material layer, and an insulating layer. The active material layer contains an active material and is laminated and joined to the current collector layer. The insulating layer contains an insulating material and is laminated and joined to the active material layer. The average particle size of the insulating material is 0.5 μm or more and 5.0 μm or less. The porosity of the insulating layer is 25% or more and 70% or less. The insulating layer overlaps the active material layer by 0.001% or more and 30% or less in the lamination direction.

[0010] The battery of the present invention has a positive electrode, a negative electrode, and an insulator provided between the positive electrode and the negative electrode. At least one of the positive electrode and the negative electrode is the electrode.

[0011] Effects of the Invention

[0012] According to the present invention, an electrode capable of suppressing an increase in internal resistance and a battery including such an electrode can be obtained. Brief Description of the Drawings

[0013] Figure 1 It is a perspective view showing the battery 1 of the first embodiment.

[0014] Figure 2 It is a perspective view showing the charge / discharge body 10 of the battery 1.

[0015] Figure 3 It shows Figure 2 a cross-sectional view of the charge / discharge body 10 on 3A-3B in

[0016] Figure 4 It shows Figure 3Cross-sectional view of the charge-discharge body 10 in region 4 in

[0017] Figure 5 is a side view schematically showing a method for manufacturing the positive electrode 100.

[0018] Figure 6 is schematically showing for Figure 5 top view of the coating state of the paste of the positive electrode current collector layer 110 of Detailed implementation manners

[0019] For the implementation manners for implementing the present invention, description will be made with reference to the accompanying drawings. In order to make each implementation manner easy to understand, in each drawing, there is a case where the size or ratio of the constituent components is exaggerated. In the cross-sectional view of the active material layer or the like, the binder or additive material around the active material is illustrated by illustrating adjacent active materials in a non-contact state. In each drawing, the same reference numerals are assigned to the same structures. The short side direction X of the positive electrode 100, the negative electrode 200, and the separator 300 in the stacked state is shown by an arrow. The long side direction Y of the positive electrode 100, the negative electrode 200, and the separator 300 in the stacked state is shown by an arrow. The stacking direction Z of the positive electrode 100, the negative electrode 200, and the separator 300 in the stacked state is shown by an arrow.

[0020] It is assumed that the electrode in the implementation manner corresponding to the present invention is a positive electrode for description. The electrode in the implementation manner corresponding to the present invention also includes a negative electrode. It is assumed that the battery 1 in the implementation manner corresponding to the present invention is a rectangular parallelepiped-shaped battery for description. The battery 1 in the implementation manner corresponding to the present invention also includes a cylindrical battery.

[0021] (Structure of the battery 1 including the positive electrode 100 in the first implementation manner)

[0022] For the structure of the battery 1 including the positive electrode 100 in the first implementation manner, reference is made to Figures 1 to 4 for description.

[0023] Figure 1 is a perspective view showing the battery 1 in the first implementation manner. Figure 2 is a perspective view showing the charge-discharge body 10 of the battery 1. Figure 3 is showing Figure 2 cross-sectional view of the charge-discharge body 10 on 3A-3B in Figure 4 is showing Figure 3 cross-sectional view of the charge-discharge body 10 in region 4 in

[0024] The battery 1 is, for example, a lithium ion secondary battery. As shown in Figures 1 to 4 , the battery 1 includes a charge-discharge body 10, an outer package 50, and an external terminal 60. Hereinafter, the main structures included in the battery 1 will be described.

[0025] The charge-discharge body 10 is charged and discharged. Figure 2 and Figure 3 The charge-discharge body 10 shown includes a positive electrode 100, a negative electrode 200, a separator 300, and an electrolyte (so-called electrolytic solution). The charge-discharge body 10 is formed, for example, by laminating a positive electrode 100, a negative electrode 200, and two separators 300 in the order of the positive electrode 100, the separator 300, the negative electrode 200, and the separator 300 and winding them into a rectangular parallelepiped shape. The electrolyte is impregnated particularly in the separator 300. The charge-discharge body 10 is covered with an insulating sheet in a state where a positive electrode current collector plate and a negative electrode current collector plate are joined.

[0026] The positive electrode 100 (electrode) is as Figure 3 shown and includes a positive electrode current collector layer 110, a positive electrode active material layer 120, and an insulating layer 130.

[0027] The positive electrode current collector layer 110 (current collector layer) is configured to be long, for example. That is, the positive electrode current collector layer 110 is formed in a foil shape. At one end in the short side direction X of the positive electrode current collector layer 110, a positive electrode current collector portion 110a is provided along the long side direction Y. The positive electrode current collector layer 110 is formed of aluminum or an aluminum alloy, for example. As the positive electrode current collector layer 110, A3003 of JIS standard is used, for example. A3003 is a non-heat-treatable Al-Mn based alloy. The thickness of the positive electrode current collector layer 110 in the lamination direction Z is, for example, 10 μm. The thickness of the positive electrode current collector layer 110 is selected in the range of 5 μm to 30 μm, for example.

[0028] The positive electrode active material layer 120 (active material layer) is provided on the positive electrode current collector layer 110. The positive electrode active material layer 120 is stacked and joined to both surfaces of the positive electrode current collector layer 110 and faces each other in the lamination direction Z. The thickness of the positive electrode active material layer 120 in the lamination direction Z is, for example, 30 μm or 40 μm. The thickness of the positive electrode active material layer 120 is selected in the range of 10 μm to 200 μm, for example.

[0029] The positive electrode active material layer 120 contains a positive electrode active material 121, a positive electrode binder 122, and a positive electrode conductive additive 123.

[0030] As the positive electrode active material 121 (active material), a lithium-containing composite oxide is used, for example. The lithium-containing composite oxide contains metal elements such as nickel (Ni), cobalt (Co), and manganese (Mn), and lithium (Li), for example. The positive electrode active material 121 is formed in a granular shape. The average particle diameter (D50) of the positive electrode active material 121 is, for example, 25 μm. The average particle diameter (D50) of the positive electrode active material 121 is selected in the range of 1 μm to 50 μm, for example.

[0031] The positive electrode binder 122 joins the positive electrode active materials 121 together. As the positive electrode binder 122, for example, polyvinylidene fluoride (PVdF / polyvinylidene difluoride), polytetrafluoroethylene (PTFE), polyethylene (PE), polystyrene, polybutadiene, polyacrylonitrile, polyvinyl fluoride, polyfluoropropylene, polyfluorochlorobutadiene, butyl rubber, nitrile rubber, styrene-butadiene rubber (SBR), polysulfide rubber, cellulose nitrate, cyanoethyl cellulose, various latexes, acrylic resins, or a mixture thereof is used.

[0032] The positive electrode conductive additive 123 improves the characteristics of the positive electrode 100. The positive electrode conductive additive 123 is arranged in a mixed manner with the positive electrode active material 121 to improve the conductivity between the positive electrode current collector layer 110 and the positive electrode active material 121. That is, the positive electrode conductive additive 123 ensures a conduction path between the positive electrode current collector layer 110 and the positive electrode active material 121 in the positive electrode 100. As the positive electrode conductive additive 123, for example, a carbon-based material is used. The carbon-based material is, for example, crystalline carbon, amorphous carbon, or a mixture thereof. Crystalline carbon is, for example, artificial graphite, natural graphite, or a mixture thereof. Natural graphite is, for example, flake graphite, massive graphite, or earthy graphite. Amorphous carbon is, for example, carbon black. Carbon black is, for example, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal cracking carbon black, or a mixture thereof.

[0033] The insulating layer 130 is laminated and joined to the positive electrode active material layer 120 as Figure 4 shown. The porosity of the insulating layer 130 is 25% or more and 70% or less. The porosity corresponds to the electrolyte retention rate. The insulating layer 130 overlaps the positive electrode active material layer 120 by 0.001% or more and 30% or less along the lamination direction Z. 0.001% or more and 30% or less is the volume ratio. The thickness of the insulating layer 130 along the lamination direction Z is 1.0 μm or more and 10.0 μm or less. As Figure 4 shown, the region of the thickness t2 of the insulating layer 130 along the lamination direction Z and the region of the thickness t1 of the positive electrode active material layer 120 partially overlap in the region of the thickness t3 along the lamination direction Z. The insulating layer 130 suppresses the intrusion of foreign substances into the positive electrode 100.

[0034] In the insulating layer 130, as Figure 4 shown, it contains an insulating material 131, a binder 132, and an additive material 133.

[0035] The insulating material 131 is an inorganic or organic substance. The insulating material 131 is, for example, boehmite or alumina. The insulating material 131 is formed in a granular shape. The average particle diameter (D50) of the insulating material 131 is 0.5 μm or more and 5.0 μm or less. The average particle diameter (D50) of the insulating material 131 is, for example, 1.2 μm. The insulating material 131 has insulating properties. The insulating material 131 preferably has heat resistance. The ratio of the insulating material 131 in the insulating layer 130 is, for example, 98%.

[0036] The binder 132 joins between the insulating materials 131. The binder 132 uses polyvinylidene fluoride (PVdF / polyvinylidene difluoride), polytetrafluoroethylene (PTFE), polyethylene (PE), polystyrene, polybutadiene, polyacrylonitrile, polyvinyl fluoride, polyfluoropropylene, polyfluorochloroprene, butyl rubber, nitrile rubber, styrene-butadiene rubber (SBR), polysulfide rubber, cellulose nitrate, cyanoethyl cellulose, various latexes, acrylic resins, or a mixture thereof. The binder 132 is, for example, PVdf. The binder 132 has insulating properties. The ratio of the binder 132 in the insulating layer 130 is, for example, 1.9%.

[0037] The additive material 133, for example, evenly disperses both the insulating material 131 and the binder 132. The additive material 133 is, for example, a dispersant. The dispersant is, for example, a carboxylic acid compound. The ratio of the additive material 133 in the insulating layer 130 is, for example, 0.1%. The additive material 133 is not essential for the insulating layer 130.

[0038] The negative electrode 200 is as Figure 3 shown and includes a negative electrode current collector layer 210 and a negative electrode active material layer 220.

[0039] The negative electrode current collector layer 210 is configured in a strip shape, for example. That is, the negative electrode current collector layer 210 is formed in a foil shape. At one end in the short side direction X of the negative electrode current collector layer 210, a negative electrode current collecting portion 210a is provided along the long side direction Y. The negative electrode current collecting portion 210a of the negative electrode current collector layer 210 faces the positive electrode current collecting portion 110a of the positive electrode current collector layer 110 in the short side direction X. The negative electrode current collector layer 210 is formed of copper or a copper alloy, for example. The thickness of the negative electrode current collector layer 210 in the stacking direction Z is, for example, 10 μm. The thickness of the negative electrode current collector layer 210 is selected within the range of 5 μm to 30 μm, for example.

[0040] The negative electrode active material layer 220 is disposed on the negative electrode current collector layer 210. The negative electrode active material layers 220 face each other in the stacking direction Z in a state of being joined to both surfaces of the negative electrode current collector layer 210. The negative electrode active material layer 220 has a longer width in the short side direction X than the positive electrode active material layer 120. In a state where the negative electrode 200 faces the positive electrode 100 with the separator 300 therebetween, both ends of the negative electrode active material layer 220 in the short side direction X are located outside the short side direction X compared to both ends of the positive electrode active material layer 120 in the short side direction X. The thickness of the negative electrode active material layer 220 in the stacking direction Z is, for example, 30 μm or 40 μm. The thickness of the negative electrode active material layer 220 is selected, for example, within the range of 10 μm to 200 μm.

[0041] The negative electrode active material layer 220 contains a negative electrode active material 221 and a negative electrode binder 222. The negative electrode active material layer 220 may also contain a negative electrode conductive additive 223.

[0042] As the negative electrode active material 221, carbon is used, for example. The carbon is, for example, graphite, non-graphitizable carbon (hard carbon), or graphitizable carbon (soft carbon). The graphite is, for example, natural graphite or artificial graphite. The natural graphite is, for example, flake graphite, massive graphite, or earthy graphite. The negative electrode active material 221 is formed in a granular shape. The average particle diameter (D50) of the negative electrode active material 221 is, for example, 25 μm. The average particle diameter (D50) of the negative electrode active material 221 is selected, for example, within the range of 1 μm to 50 μm.

[0043] The negative electrode binder 222 joins the negative electrode active materials 221 together. As the negative electrode binder 222, the same material as the positive electrode binder 122 is used, for example.

[0044] The negative electrode conductive additive 223 improves the characteristics of the negative electrode 200. The negative electrode conductive additive 223 is disposed in a mixed manner with the negative electrode active material 221 to improve the conductivity between the negative electrode current collector layer 210 and the negative electrode active material 221. That is, the negative electrode conductive additive 223 secures a conduction path between the negative electrode current collector layer 210 and the negative electrode active material 221 in the negative electrode 200.

[0045] The negative electrode 200 may include an insulating layer that covers the negative electrode active material layer 220. The insulating layer has heat resistance. The insulating layer contains, for example, an inorganic material or an organic substance, and a binder. The inorganic material is, for example, alumina particles.

[0046] The separator 300 (insulator) insulates the positive electrode 100 from the negative electrode 200. The insulating layer 130 of the positive electrode 100 faces the negative electrode 200 along the stacking direction Z with the separator 300 in between. Additionally, the separator 300 holds an electrolyte (so-called electrolytic solution). The separator 300 is formed in a long strip shape. The separator 300 has a greater width in the short side direction X compared to the negative electrode active material layer 220. In a state where the positive electrode 100 and the negative electrode 200 face each other with the separator 300 in between, both ends of the positive electrode active material layer 120 in the short side direction X are within the range of the separator 300 in the short side direction X, and both ends of the negative electrode active material layer 220 in the short side direction X are within the range of the separator 300 in the short side direction X. The thickness of the separator 300 along the stacking direction Z is, for example, 20 μm. The thickness of the separator 300 is selected, for example, within the range of 5 μm to 60 μm.

[0047] As shown in Figure 3 , the separator 300 is formed of a porous material. As the porous material, for example, polyethylene, polypropylene, polyester, cellulose, or polyamide is used. The separator 300 can adopt a structure in which multiple different porous materials are laminated.

[0048] The separator 300 may have an insulating layer. The insulating layer has heat resistance. The insulating layer contains, for example, an inorganic material or an organic substance, and a binder. The inorganic material is, for example, alumina particles.

[0049] The electrolyte allows lithium ions to flow between the positive electrode 100 and the negative electrode 200. The electrolyte is also called an electrolytic solution.

[0050] The electrolyte contains an organic solvent and a lithium salt. The electrolyte may also contain an additive material.

[0051] As the organic solvent, for example, a carbonate such as ethylene carbonate is used. As the lithium salt, for example, lithium hexafluorophosphate (LiPF 6 ) is used. As the additive material, for example, lithium hexafluorophosphate (LiPF 6 ) is used.

[0052] The exterior body 50 houses the charge-discharge body 10. As shown in Figure 1 , the exterior body 50 includes a container 51, a lid 52, a liquid injection plug 53, and a rupture valve 54. The container 51 is formed in a rectangular parallelepiped shape. The charge-discharge body 10 is housed in the container 51. The lid 52 is welded to the container 51. A liquid injection hole is provided in the lid 52. The liquid injection hole is a hole for injecting an electrolyte (so-called electrolytic solution) into the interior of the battery 1. The liquid injection plug 53 is installed in the liquid injection hole of the lid 52. After injecting the electrolyte into the interior of the battery 1 through the liquid injection hole, the liquid injection plug 53 is inserted into the liquid injection hole and welded. The rupture valve 54 is provided in the lid 52. The rupture valve 54 is integrally formed with the lid 52. The rupture valve 54 ruptures outward from the battery 1 when the internal pressure of the battery 1 exceeds a specified value.

[0053] The external terminal 60 relays the input and output of electric power between the current collector disposed inside the battery 1 and the electrical machine disposed outside the battery 1. The electrical machine is, for example, a relay and an inverter disposed in a vehicle. In addition, the external terminals 60 provided in one battery 1 are electrically connected to the external terminals 60 provided in other batteries 1 via a bus bar or the like, and relay the input and output of electric power between one battery 1 and the other batteries 1. As shown in Figure 1 FIG. 3, the external terminal 60 includes a positive electrode terminal 61 and a negative electrode terminal 62. The positive electrode terminal 61 is electrically connected to the positive electrode current collecting portion 110a of the positive electrode current collecting layer 110 via a positive electrode current collecting plate. The positive electrode terminal 61 is mounted on the lid 52 with a positive electrode insulating member interposed therebetween. The negative electrode terminal 62 is electrically connected to the negative electrode current collecting portion 210a of the negative electrode current collecting layer 210 via a negative electrode current collecting plate. The negative electrode terminal 62 is mounted on the lid 52 with a negative electrode insulating member interposed therebetween.

[0054] (Manufacturing method of the positive electrode 100 of the first embodiment)

[0055] Regarding the manufacturing method of the positive electrode 100, reference is made to Figure 5 and Figure 6 for description. Figure 5 FIG. 4 is a side view schematically showing the manufacturing method of the positive electrode 100. Figure 6 FIG. 5 is a top view schematically showing the coating state of the paste of the positive electrode current collecting layer 110 for Figure 5 FIG. 4.

[0056] In the manufacturing method of the positive electrode 100, in the coating step, the positive electrode active material layer paste 1100 and the insulating layer paste 1200 are coated. In the coating step, for the positive electrode current collecting layer 110, the positive electrode active material layer paste 1100 is coated. In addition, in the coating step, for the positive electrode active material layer paste 1100, the insulating layer paste 1200 is coated.

[0057] The positive electrode active material layer paste 1100 used in the coating step contains a solvent in addition to the materials constituting the positive electrode active material layer 120. Among the materials constituting the positive electrode active material layer 120, a positive electrode active material 121, a positive electrode binder 122, and a positive electrode conductive additive 123 are contained. The solvent disperses the materials contained in the positive electrode active material layer 120. As the solvent, for example, one having gasification property at a temperature above room temperature is used. The solvent is, for example, N-methyl-2-pyrrolidone (NMP).

[0058] The insulating layer paste 1200 used in the coating process contains a solvent in addition to the materials constituting the insulating layer 130. The solvent disperses the insulating material 131, the binder 132, etc. contained in the insulating layer 130. As the solvent, for example, one having gasification properties at a temperature above room temperature is used. The solvent is, for example, N-methyl-2-pyrrolidone (NMP).

[0059] The manufacturing apparatus 1000 for the positive electrode 100 is as Figure 5 shown and includes a transfer unit 1010, a coating unit 1020, a drying unit 1030, and a calendering unit 1040.

[0060] The transfer unit 1010 is as Figure 5 shown and transfers the components constituting the positive electrode 100. The transfer unit 1010 includes transfer rollers 1011.

[0061] The transfer unit 1010 transfers the positive electrode current collector layer 110 in a wound state on an unillustrated first roller to the coating unit 1020, the drying unit 1030, and the calendering unit 1040 via the transfer rollers 1011 and the like. The transfer unit 1010 winds the positive electrode current collector layer 110 after the positive electrode active material layer 120 and the insulating layer 130 are joined around an unillustrated second roller. When the second roller on which the positive electrode current collector layer 110 is mounted rotates, the transfer rollers 1011 and the first roller in contact with the positive electrode current collector layer 110 also rotate to transfer the positive electrode current collector layer 110. The transfer direction H of the positive electrode current collector layer 110 corresponds to the long side direction Y of the positive electrode current collector layer 110.

[0062] The coating unit 1020 is as Figure 5 shown and coats a paste on the positive electrode current collector layer 110 and the like. The coating unit 1020 includes a first coating head 1021, a first liquid supply pipe 1022, a second coating head 1023, and a second liquid supply pipe 1024.

[0063] The first coating head 1021 is as Figure 5 and Figure 6 shown and is disposed along the short side direction X orthogonal to the transfer direction H of the positive electrode current collector layer 110, that is, the long side direction Y of the positive electrode current collector layer 110. In the first coating head 1021, a long strip-shaped opening is formed. The long strip-shaped opening is connected to the first liquid supply pipe 1022. For the first coating head 1021, the positive electrode active material layer paste 1100 is supplied from an unillustrated container via an unillustrated pump and the first liquid supply pipe 1022. The first coating head 1021 faces the transfer roller 1011 with the positive electrode current collector layer 110 interposed therebetween. The first coating head 1021 coats the positive electrode active material layer paste 1100 on the positive electrode current collector layer 110 in a state where the positive electrode current collector layer 110 is being transferred.

[0064] The second coating head 1023 is as Figure 5 and Figure 6As shown, it is arranged along the short side direction X of the positive current collector layer 110. The second coating head 1023 is juxtaposed with the first coating head 1021 along the conveying direction H of the positive current collector layer 110. The second coating head 1023 is located on the downstream side of the positive current collector layer 110 in the conveying direction H with respect to the first coating head 1021. In the second coating head 1023, a long strip-shaped opening is formed. The long strip-shaped opening is connected to the second liquid supply pipe 1024. For the second coating head 1023, the insulating layer slurry 1200 is supplied from a container (not shown) via a pump (not shown) and the second liquid supply pipe 1024. The second coating head 1023 faces the conveying roller 1011 with the positive current collector layer 110 interposed therebetween. The second coating head 1023 coats the insulating layer slurry 1200 on the positive electrode active material layer slurry 1100 in a state where the positive current collector layer 110 is being conveyed. That is, the insulating layer slurry 1200 is coated in a manner that covers the positive electrode active material layer slurry 1100. The insulating layer slurry 1200 may also be coated on the positive current collector layer 110 so as to exceed the end of the positive electrode active material layer slurry 1100 in the short side direction X and along the long side direction Y of the positive electrode active material layer.

[0065] The drying unit 1030 is as Figure 5 shown, and dries the slurry. The drying unit 1030 is provided on the downstream side of the coating unit 1020 in the conveying direction H of the positive current collector layer 110. The drying unit 1030 includes a dryer 1031.

[0066] The dryer 1031 is as Figure 5 shown, and is arranged along the conveying direction H of the positive current collector layer 110, that is, along the long side direction Y of the positive current collector layer 110. The dryer 1031 dries the positive electrode active material layer slurry 1100 and the insulating layer slurry 1200 in a state where the positive current collector layer 110 is being conveyed. The dryer 1031 has a plurality of heat sources along the conveying direction H of the positive current collector layer 110. The dryer 1031 uses the plurality of heat sources to dry the positive electrode active material layer slurry 1100 and the insulating layer slurry 1200 based on various conditions.

[0067] In the drying unit 1030, the positive electrode active material layer slurry 1100 constitutes the positive electrode active material layer 120 due to the vaporization of the solvent. The NMP contained in the positive electrode active material layer slurry 1100 vaporizes, whereby the positive electrode active material layer slurry 1100 dries. The thickness of the positive electrode active material layer slurry 1100 in the stacking direction Z decreases as it dries. The positive electrode active material layer 120 is joined to the positive current collector layer 110. The insulating layer slurry 1200 constitutes the insulating layer 130 due to the vaporization of the solvent. The NMP contained in the insulating layer slurry 1200 vaporizes, whereby the insulating layer slurry 1200 dries. The thickness of the insulating layer slurry 1200 in the stacking direction Z decreases as it dries. The insulating layer 130 is joined to the positive electrode active material layer 120.

[0068] The calendering section 1040 is as follows Figure 5 As shown, the calendering is performed on the positively charged current collector layer 110, the positive electrode active material layer 120, and the insulating layer 130 in a mutually joined state. The calendering section 1040 is provided on the downstream side in the transport direction H of the positively charged current collector layer 110 with respect to the drying section 1030. The calendering section 1040 includes a calender roll 1041 and a driven roll 1042.

[0069] The calender roll 1041 is as follows Figure 5 As shown, it is provided along the short side direction X of the positively charged current collector layer 110. The calender roll 1041 faces the insulating layer 130 in the positive electrode 100. The driven roll 1042 is as follows Figure 5 As shown, it is provided along the short side direction X of the positively charged current collector layer 110. The driven roll 1042 faces the calender roll 1041 across the positive electrode 100. The driven roll 1042 faces the positively charged current collector layer 110 in the positive electrode 100. The thickness of the positive electrode active material layer 120 and the insulating layer 130 is defined by the interval between the calender roll 1041 and the driven roll 1042 in the calendering section 1040.

[0070] In the method for manufacturing the positive electrode 100, with reference to Figure 5 and Figure 6 The structure described is a structure in which the positive electrode active material layer 120 and the insulating layer 130 are joined to one side of the positively charged current collector layer 110. That is, Figure 5 and Figure 6 The method for manufacturing the positive electrode 100 shown is a method for manufacturing a so-called single-sided coated positive electrode 100. On the other hand, as shown in Figure 3 For the positive electrode 100, for example, the positive electrode active material layer 120 and the insulating layer 130 are joined to both sides of the positively charged current collector layer 110. That is, Figure 3 The positive electrode 100 shown is formed by so-called double-sided coating. Therefore, in the method for manufacturing the positive electrode 100, after the structure described with reference to Figure 5 and Figure 6 is described, the positive electrode active material layer 120 and the insulating layer 130 are joined to the other side of the positive electrode active material layer 120.

[0071] (Comparison experiment results of the positive electrode 100 of the first embodiment and the positive electrode of the comparative example)

[0072] The comparison experiment results of the positive electrode 100 of the first embodiment and the positive electrode of the comparative example will be described with reference to Table 1.

[0073] [Table 1]

[0074]

[0075] The insulating layers under Conditions 1 and 2 correspond to the insulating layer 130 of the positive electrode 100 of the embodiment. On the other hand, the insulating layers under Conditions 3 and 4 correspond to the insulating layer of the positive electrode of the comparative example.

[0076] In Condition 1, the ratio of the insulating material 131 in the insulating layer 130 is set to 98%. Additionally, in Condition 1, the ratio of the binder 132 in the insulating layer 130 is set to 1.9%. In Condition 1, the ratio of the solid portion in the insulating layer slurry 1200 is set to 30%. The solid portion is the insulating material 131, the binder 132, and the additive material 133. In Condition 1, the viscosity of the insulating layer slurry 1200 is 325 mPa·s.

[0077] In Condition 2, different from Condition 1, the ratio of the solid portion in the insulating layer slurry 1200 is set to 15%. That is, in Condition 2, compared with Condition 1, the proportion of the solvent in the insulating layer slurry 1200 is increased. In Condition 2, the viscosity of the insulating layer slurry 1200 is 100 mPa·s.

[0078] In Condition 3, different from Condition 1, the ratio of the insulating material in the insulating layer is set to 99.5%. Additionally, in Condition 3, the ratio of the binder in the insulating layer is set to 0.4%. That is, in Condition 3, compared with Condition 1, the ratio of the insulating material in the insulating layer is increased, and the ratio of the binder is decreased. In Condition 3, the viscosity of the insulating layer slurry is 100 mPa·s.

[0079] In Condition 4, different from Condition 1, the ratio of the insulating material in the insulating layer is set to 90%. Additionally, in Condition 4, the ratio of the binder in the insulating layer is set to 9.9%. That is, in Condition 4, compared with Condition 1, the ratio of the insulating material in the insulating layer is decreased, and the ratio of the binder is increased. In Condition 4, the viscosity of the insulating layer slurry is 800 mPa·s or more.

[0080] In Condition 5, different from Condition 1, the ratio of the solid portion in the insulating layer slurry 1200 is set to 10%. That is, in Condition 5, compared with Condition 1 and Condition 2, the proportion of the solvent in the insulating layer slurry 1200 is increased. In Condition 5, the viscosity of the insulating layer slurry 1200 is 3 mPa·s.

[0081] The insulating layer 130 of Condition 1 is sufficiently bonded to the positive electrode active material layer 120. The state of the interface between the insulating layer 130 of Condition 1 and the positive electrode active material layer 120 is very good. That is, the overlap between the insulating layer 130 of Condition 1 and the positive electrode active material layer 120 is relatively very small. The positive electrode 100 having the insulating layer 130 of Condition 1 can suppress the increase in resistance.

[0082] The insulating layer 130 under Condition 2 is sufficiently bonded to the positive electrode active material layer 120. The state of the interface between the insulating layer 130 and the positive electrode active material layer 120 under Condition 2 is good. That is, the overlap between the insulating layer 130 and the positive electrode active material layer 120 under Condition 2 is relatively small. The positive electrode 100 having the insulating layer 130 under Condition 2 can suppress the increase in resistance.

[0083] The insulating layer 130 under Condition 3 fails to be sufficiently bonded to the positive electrode active material layer 120. The reason is that in Condition 3, compared with Condition 1, the ratio of the insulating material in the insulating layer is increased and the ratio of the binder is decreased. When the ratio of the binder is too low, it is difficult to fix the insulating layer on the positive electrode active material layer. The state of the interface between the insulating layer 130 and the positive electrode active material layer 120 under Condition 3 is good. The positive electrode 100 having the insulating layer 130 under Condition 3 can suppress the increase in resistance.

[0084] The insulating layer 130 under Condition 4 is sufficiently bonded to the positive electrode active material layer 120. The state of the interface between the insulating layer 130 and the positive electrode active material layer 120 under Condition 4 is very good. That is, the overlap between the insulating layer 130 and the positive electrode active material layer 120 under Condition 4 is relatively very small. The positive electrode 100 having the insulating layer 130 under Condition 4 fails to suppress the increase in resistance. The reason is that in Condition 4, compared with Condition 1, the ratio of the insulating material in the insulating layer is decreased and the ratio of the binder is increased. The binder does not participate in the battery reaction.

[0085] The insulating layer 130 under Condition 5 is not sufficiently bonded to the positive electrode active material layer 120. The state of the interface between the insulating layer 130 and the positive electrode active material layer 120 under Condition 5 is not good. That is, the overlap between the insulating layer 130 and the positive electrode active material layer 120 under Condition 5 is relatively large. The reason is that in Condition 5, the viscosity of the insulating layer slurry 1200 is very low (3 mPa·s). The positive electrode 100 having the insulating layer 130 under Condition 5 fails to suppress the increase in resistance.

[0086] (Effects of the battery 1 etc. including the positive electrode 100 of the first embodiment)

[0087] The effects of the battery 1 etc. including the positive electrode 100 of the first embodiment will be described.

[0088] (1)(6)(7) The positive electrode 100 (electrode) has an insulating layer 130 (insulating layer). The insulating layer 130 is laminated and joined with the positive electrode active material layer 120 (active material layer), and contains an insulating material 131 with insulating properties. The average particle diameter (D50) of the insulating material 131 is 0.5 μm or more and 5.0 μm or less. The porosity of the insulating layer 130 is 25% or more and 70% or less. The overlap of the insulating layer 130 and the positive electrode active material layer 120 along the lamination direction Z is 0.001% or more and 30% or less. The overlap of the insulating layer 130 and the positive electrode active material layer 120 is based on the volume ratio. According to such a structure, the overlap of the insulating layer 130 that does not participate in the battery reaction relative to the positive electrode active material layer 120 that participates in the battery reaction can be suppressed below a certain level. In addition, according to such a structure, the electrolyte can be sufficiently immersed in the insulating layer 130, making the transport of lithium ions smooth. As a result, a positive electrode 100 with an increase in internal resistance suppressed can be obtained. In addition, according to such a structure, a battery 1 having a positive electrode 100 with an increase in internal resistance suppressed can be obtained.

[0089] (2) The overlap of the insulating layer 130 and the positive electrode active material layer 120 along the lamination direction Z is 1% or less. According to such a structure, since the overlap of the insulating layer 130 and the positive electrode active material layer 120 is suppressed below 1%, a positive electrode 100 with a further suppressed increase in internal resistance can be obtained.

[0090] (3) The overlap of the insulating layer 130 and the positive electrode active material layer 120 along the lamination direction Z is 0.5% or less. According to such a structure, since the overlap of the insulating layer 130 and the positive electrode active material layer 120 is suppressed below 0.5%, a positive electrode 100 with a further suppressed increase in internal resistance can be obtained.

[0091] (4) The insulating material 131 contains boehmite or alumina. According to such a structure, the insulating material 131 can be composed of a material with high versatility.

[0092] (5) The thickness of the insulating layer 130 along the lamination direction Z is 1.0 μm or more and 10.0 μm or less. According to such a structure, the proportion of the insulating layer 130 in the positive electrode 100 can be suppressed below a certain proportion. As a result, the energy density of the positive electrode 100 can be maintained above a certain level.

[0093] (8) The insulating layer 130 faces the negative electrode 200 along the lamination direction Z with a separator 300 (insulator) in between. According to such a structure, the insulation between the positive electrode 100 and the negative electrode 200 can be compensated by the separator 300.

[0094] (Battery of other embodiments)

[0095] The battery of the present invention is not limited to the structure of the battery described in the embodiments, and can be appropriately configured based on the content described in the claims.

[0096] The embodiments are described in detail or briefly for the purpose of easily understanding the present invention, and do not need to have all the structures described, or may have structures not shown in the drawings. In addition, for a part of the structure of the embodiments, it can be deleted, or replaced with the structure of other embodiments, or combined with the structure of other embodiments.

[0097] In the electrode (positive electrode) of the present invention, the positive electrode active material is not limited to the nickel (Ni), cobalt (Co), and manganese (Mn) system. For example, the positive electrode active material of the present invention can also adopt the Fe (olivine iron) system.

[0098] In the electrode (negative electrode) of the present invention, the negative electrode active material is not limited to the carbon system. For example, the negative electrode active material of the present invention can also adopt the silicon system.

[0099] The battery of the present invention is not limited to the structure in which the charge and discharge body is sealed with a container and a lid. The battery of the present invention can be applied to the structure in which the charge and discharge body is sealed with a laminated film.

[0100] The battery of the present invention is not limited to a lithium-ion battery. For example, the battery of the present invention can be applied to a nickel-metal hydride battery.

[0101] The battery of the present invention is not limited to a secondary battery. The battery of the present invention can be applied to a primary battery.

[0102] In the battery of the present invention, the charge and discharge body is not limited to the winding type in which the positive electrode, the separator, and the negative electrode, which are respectively formed in a long strip shape, are bundled and wound. As the charge and discharge body of the battery of the present invention, a laminated type in which the positive electrode, the separator, and the negative electrode, which are respectively formed in a rectangular shape, are alternately laminated in multiple layers can be applied.

[0103] In the battery of the present invention, as the charge and discharge body, a laminated type in which a plurality of positive electrodes and a plurality of negative electrodes, which are formed in a relatively short shape, are alternately arranged opposite to each other with a separator interposed therebetween for a single separator formed in a long strip shape can be applied. The charge and discharge body having such a structure is laminated with the separator folded, so that the positive electrode and the negative electrode are opposite to each other with the separator interposed therebetween.

[0104] In the battery of the present invention, the charge and discharge body is not limited to the type having a rectangular parallelepiped shape. As the charge and discharge body of the battery of the present invention, a type having a cylindrical shape or a columnar shape can be applied.

[0105] In the battery of the present invention, the charge and discharge body is not limited to the structure in which a separator having insulating properties is provided between the positive electrode and the negative electrode. The battery of the present invention can be applied to a structure in which no separator is provided, but an insulating layer is provided in at least one of the positive electrode and the negative electrode. Such a structure is equivalent to a so-called separator-free structure.

[0106] In the battery of the present invention, the charge-discharge body is not limited to a structure in which only one is provided. The battery of the present invention can be applied to a structure in which two or more charge-discharge bodies are provided.

[0107] The electrodes (positive electrode, negative electrode) of the present invention are not limited to a structure in which the end of the current collector layer is joined to the current collector plate. The electrodes of the battery of the present invention can be applied to a type in which an electrode tab protruding outward from the edge of the current collector layer is joined to the current collector plate.

[0108] The electrodes (positive electrode, negative electrode) of the present invention are not limited to a structure in which the active material layer is joined to both sides of the current collector layer. The electrodes can be applied to a structure in which the active material layer is joined to only one side of the current collector layer.

[0109] The manufacturing method of the electrodes (positive electrode, negative electrode) of the present invention is not limited to a structure in which the active material layer slurry and the insulating layer slurry are simultaneously coated and dried to form the active material layer and the insulating layer. The manufacturing method of the electrodes (positive electrode, negative electrode) of the present invention can be applied to a structure in which the active material layer slurry is first coated on the current collector layer and dried to form the active material layer. In such a structure, then the insulating layer slurry is coated on the active material layer and dried to form the insulating layer.

[0110] The manufacturing method of the electrodes (positive electrode, negative electrode) of the present invention is not limited to a structure in which the first coating head and the second coating head are provided independently. The manufacturing method of the electrodes (positive electrode, negative electrode) of the present invention can be applied to a structure in which the first coating head and the second coating head are integrated.

[0111] Symbol Explanation

[0112] 1 Battery,

[0113] 10 Charge-discharge body,

[0114] 50 Outer package,

[0115] 51 Container,

[0116] 52 Cover,

[0117] 53 Liquid injection plug,

[0118] 54 Cracking valve,

[0119] 60 External terminal,

[0120] 61 Positive terminal,

[0121] 62 Negative terminal,

[0122] 100 Positive electrode (electrode),

[0123] 110 Positive electrode current collector layer (current collector layer),

[0124] 110a positive current collector part

[0125] 120 positive active material layer (active material layer)

[0126] 121 positive active material (active material)

[0127] 122 positive binder

[0128] 123 positive conductive additive

[0129] 130 insulating layer

[0130] 131 insulating material

[0131] 132 binder

[0132] 133 additive (additive part)

[0133] 200 negative electrode

[0134] 210 negative current collector layer

[0135] 210a negative current collector part

[0136] 220 negative active material layer

[0137] 221 negative active material

[0138] 222 negative binder

[0139] 223 negative conductive additive

[0140] 300 separator (insulator)

[0141] 1000 manufacturing device

[0142] 1010 conveying part

[0143] 1011 conveying roller

[0144] 1020 coating part

[0145] 1021 first coating head

[0146] 1022 first liquid supply pipe

[0147] 1023 second coating head

[0148] 1024 second liquid supply pipe

[0149] 1030 drying part

[0150] 1031 dryer

[0151] 1040 Calendering section,

[0152] 1041 Calendering roll,

[0153] 1042 Driven roll,

[0154] 1100 Cathode active material layer slurry,

[0155] 1200 Insulating layer slurry,

[0156] t1 (thickness of the cathode active material layer 120 in the stacking direction Z),

[0157] t2 (thickness of the insulating layer 130 in the stacking direction Z),

[0158] t3 (thickness of the overlapping part of the region with thickness t1 and the region with thickness t2 along the stacking direction Z),

[0159] X (short side direction of the cathode 100, anode 200, and separator 300),

[0160] Y (long side direction of the cathode 100, anode 200, and separator 300),

[0161] Z (stacking direction of the cathode 100, anode 200, and separator 300),

[0162] H (transport direction (long side direction Y) of the cathode 100, anode 200, and separator 300).

Claims

1. An electrode, comprising: Current collecting layer; an active material layer, which contains an active material and is laminated and bonded to the current collecting layer; and an insulating layer, which contains an insulating material and is laminated and bonded to the active material layer; The average particle size of the insulating material is greater than or equal to 0.5 μm and less than or equal to 5.0 μm. The porosity of the insulating layer is greater than or equal to 25% and less than or equal to 70%. The ratio of the insulating layer to the active material layer overlapping each other in a stacking direction is 0.001% or more and 30% or less.

2. The electrode according to claim 1, wherein The ratio of the insulating layer and the active material layer overlapping each other in the stacking direction is 1% or less.

3. The electrode according to claim 1, wherein The ratio of the insulating layer and the active material layer overlapping each other in the stacking direction is 0.5% or less.

4. The electrode according to claim 1, wherein The insulating material contains boehmite or alumina.

5. The electrode according to claim 1, wherein The thickness of the insulating layer in the stacking direction is 1.0 μm or more and 10.0 μm or less.

6. The electrode according to claim 1, wherein The current collecting layer is a positive electrode current collecting layer, The active material layer is a positive electrode active material layer containing a positive electrode active material.

7. A battery comprising a positive electrode and a negative electrode, At least one of the positive electrode and the negative electrode comprises: Current collecting layer; an active material layer, which contains an active material and is laminated and bonded to the current collecting layer; and an insulating layer, which contains an insulating material and is laminated and bonded to the active material layer; The average particle size of the insulating material is 0.5 μm or more and 5.0 μm or less, The porosity of the insulating layer is greater than or equal to 25% and less than or equal to 70%. The ratio of the insulating layer to the active material layer overlapping each other in the stacking direction is 0.001% or more and 30% or less, The insulating layer of the positive electrode faces the negative electrode in the stacking direction, or the insulating layer of the negative electrode faces the positive electrode in the stacking direction.

8. The battery according to claim 7, having an insulator disposed between the positive electrode and the negative electrode, The insulating layer of the positive electrode faces the negative electrode in the stacking direction via the insulator, or the insulating layer of the negative electrode faces the positive electrode in the stacking direction via the insulator.

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