Electrode and lithium ion secondary battery using the same

Abstract

The problem of the present invention is to provide an electrode for a lithium-ion secondary battery and a lithium-ion secondary battery using this electrode, and the electrode for the lithium-ion secondary battery can prevent the electrode from cracking. To solve the above problems, the electrode of the present invention is an electrode (1, 2) for a lithium-ion secondary battery (100), which includes: a current collector (10, 20), which has a specific thickness and is a metal porous body having at least one corner portion when viewed three-dimensionally; and an electrode composite material (18, 28), which is filled in its pore portion. In the current collector, a composite material filling region (11, 21) and a composite material unfilled region (15, 25) are present in the corner portion of the current collector. The composite material filling region (11, 21) is filled with the electrode composite material, and the composite material unfilled region (15, 25) is not filled with the electrode composite material or is filled with a highly elastic filler having a smaller elastic modulus than the electrode composite material.

Description

Technical Field

[0001] The present invention relates to an electrode and a lithium-ion secondary battery using the electrode. Background Art

[0002] Conventionally, as a secondary battery having a high energy density, lithium-ion secondary batteries have been widely popularized. A liquid lithium-ion secondary battery has the following cell structure, that is, a separator is present between a positive electrode and a negative electrode, and a liquid electrolyte (electrolyte solution) is filled. Further, in the case of an all-solid battery in which the electrolyte is solid, it has the following cell structure, that is, a solid electrolyte is present between the positive electrode and the negative electrode. A plurality of such single cells are stacked to form a lithium-ion secondary battery.

[0003] Here, in order to increase the packing density of the electrode active material, the use of a metal porous body as a current collector constituting a positive electrode layer and a negative electrode layer has been proposed (for example, refer to Patent Document 1). The metal porous body has a mesh structure with fine pores and a large surface area. An electrode composite material containing an electrode active material is filled inside the mesh structure, whereby the amount of the electrode active material per unit area of the electrode layer can be increased.

[0004] [Prior Art Documents]

[0005] (Patent Document)

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-186139 Summary of the Invention

[0007] [Problems to be Solved by the Invention]

[0008] Figure 7 is a schematic view of an embodiment of a conventional lithium-ion secondary battery, Figure 7 (a) is a sectional view, Figure 7 (b) is a plan view. As Figure 7 shown, the lithium-ion secondary battery 500 is composed of five layers: a negative electrode 51, a solid electrolyte 54, a positive electrode 52, a solid electrolyte 54, and a negative electrode 51. The number of layers is assumed for the sake of explanation and the required number can be stacked as appropriate. 512 and 522 are tab ear converging portions on each electrode, and 513 and 523 are tab ears on each electrode.

[0009] Figure 8 is Figure 7An enlarged cross-sectional view of the composite material filling region 511 in the negative electrode 51. The composite material filling region 511 of the negative electrode 51 is composed of a negative electrode current collector 510 using the above-mentioned metal porous body and a negative electrode composite material 518 filled in its pore portion V1. Similarly, the composite material filling region 521 of the positive electrode 52 is composed of a positive electrode current collector 520 using the above-mentioned metal porous body and a positive electrode composite material 528 filled in its pore portion V2 (the figure number of the positive electrode is added in parentheses).

[0010] From the viewpoint of increasing the energy density, the current collectors of the metal porous bodies in the negative electrode 51 and the positive electrode 52 are Figure 7 as shown in (b), and are in the shape of a rectangle with four sides when viewed from above. And since the whole is a three-dimensional structure with a mesh structure, it has a specific thickness, that is, except for the tab converging portions 512 and 522, the whole is in a substantially rectangular parallelepiped shape. Therefore, there are corner portions A in the current collector ( Figure 7 in, the positions circled by circles).

[0011] It is known that since the electrode composite material usually has a relatively large elastic modulus and is hard, if the thickness of the current collector is increased in order to increase the energy density, the electrode is likely to break due to stamping processes and subsequent vibrations, etc. In Figure 7 (a), the upper and lower plates P are stamping plates, and are clamped from above and below by the plates P and stamped in the direction of the arrow in the figure. At this time, breakage is particularly likely to occur at the corner portions A of the negative electrode current collector 510 and the positive electrode current collector 520 where stress is concentrated. The breakage of the electrode will cause failures such as short circuits, so improvement is needed. This breakage may also occur in the liquid electrolyte, but is particularly obvious in the solid battery using the solid electrolyte.

[0012] The present invention has been made in view of the above circumstances, and an object thereof is to provide an electrode and a lithium ion secondary battery using this electrode, which can particularly effectively prevent the breakage of the electrode at the corner portion.

[0013] [Technical means for solving the problem]

[0014] (1) An electrode, which is an electrode for a lithium ion secondary battery,

[0015] The aforementioned electrode includes: a current collector, which has a specific thickness and is a metal porous body having at least one corner portion when observed three-dimensionally; and an electrode composite material, which is filled in the pore portion of the aforementioned metal porous body;

[0016] In the aforementioned current collector, a composite material filling region and a composite material unfilled region exist in the aforementioned corner portion of the current collector. The composite material filling region is filled with the aforementioned electrode composite material, and the composite material unfilled region is not filled with the aforementioned electrode composite material or is filled with a highly elastic filler having an elastic modulus smaller than that of the aforementioned electrode composite material.

[0017] According to the invention of (1), a composite material unfilled region is provided at the corner portion of the current collector. Thus, the elasticity of the current collector and the elasticity of the highly elastic filler provided as needed can be utilized to relieve the stress on the corner portion and prevent the electrode from cracking.

[0018] (2) The electrode according to (1), wherein, at the corner portion of the current collector, the composite material filled region is curved.

[0019] According to the invention of (2), by setting the top of the composite material filled region as a curved surface, that is, an R shape, the stress on the corner portion can be relieved to prevent the electrode from cracking.

[0020] (3) The electrode according to (1) or (2), wherein the highly elastic filler is at least one selected from an insulating material, a reinforcing material, and a heat insulating material.

[0021] According to the invention of (3), a solid battery can be provided, which can improve the protection function of the corner portion of the current collector in terms of electricity, strength, and heat, and has higher durability.

[0022] (4) The electrode according to any one of (1) to (3), wherein the composite material unfilled region also exists in the outer peripheral region of the current collector.

[0023] According to the invention of (4), a solid battery can be provided, which can relieve the stress applied from the outside of the outer peripheral region in addition to the corner portion of the current collector, and has higher durability.

[0024] (5) The electrode according to any one of (1) to (4), wherein the composite material unfilled region also exists as an intermediate layer in the thickness direction of the current collector.

[0025] According to the invention of (5), a solid battery can be provided, which can utilize the intermediate layer to relieve the stress applied from the out-of-plane thickness direction of the current collector in addition to the corner portion of the current collector, and has higher durability.

[0026] (6) A lithium ion secondary battery uses the electrode according to any one of (1) to (5) as a positive electrode and a negative electrode. The positive electrode, the electrolyte layer, and the negative electrode are alternately arranged, and, among the adjacent electrodes arranged, the shapes and sizes of the surfaces of the mutually facing composite material filled regions are substantially the same.

[0027] According to the invention of (6), a solid battery can be provided, which can improve the ion conductivity without waste and with higher efficiency by making the shapes and areas of the opposing composite material filled regions between adjacent electrodes the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 FIG. is a schematic view of a first embodiment of a lithium ion secondary battery of the present invention, Figure 1 (a) is a sectional view, Figure 1 (b) is a plan view.

[0029] Figure 2 is Figure 1 an enlarged sectional view of the composite material filling area in

[0030] Figure 3 FIG. is a schematic sectional view of a second embodiment of a lithium ion secondary battery of the present invention.

[0031] Figure 4 (a) is Figure 3 a plan view of the positive electrode in Figure 4 (b) is Figure 3 a sectional view of the positive electrode in

[0032] Figure 5 FIG. is a schematic sectional view of a third embodiment of a lithium ion secondary battery of the present invention.

[0033] Figure 6 (a) is Figure 5 a plan view of the positive electrode in Figure 6 (b) is Figure 5 a sectional view of the positive electrode in Figure 6 (c) is Figure 5 a variation of the sectional view of the positive electrode in

[0034] Figure 7 FIG. is a schematic view of an embodiment of a conventional lithium ion secondary battery, Figure 7 (a) is a sectional view, Figure 7 (b) is a plan view.

[0035] Figure 8 is Figure 7 an enlarged sectional view of the composite material filling area in DETAILED DESCRIPTION OF THE INVENTION

[0036] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The content of the present invention is not limited to the description of the following embodiments.

[0037] In the following embodiments, a all-solid-state lithium ion battery with a solid electrolyte layer will be described as an example.

[0038] [First Embodiment]

[0039] <Overall Structure of Lithium Ion Secondary Battery>

[0040] AsFigure 1 As shown in Figure 1 , in the lithium-ion secondary battery of the present invention, the negative electrode 1 and the positive electrode 2 are alternately stacked with a solid electrolyte layer 4 interposed therebetween. That is, the single cell has a three-layer structure of negative electrode 1 / solid electrolyte layer 4 / positive electrode 2.

[0041] In the following embodiments, a so-called all-solid battery using a solid electrolyte is taken as an example for explanation, but the present invention is not limited thereto. The electrodes for the lithium-ion secondary battery of the present invention can also be applied to lithium-ion batteries using a liquid as the electrolyte. Hereinafter, each structure will be described.

[0042] <Positive electrode and negative electrode>

[0043] Regarding the positive electrode and the negative electrode, two types can be selected from the materials that can form the electrodes, and the charge-discharge potentials of the two compounds can be compared. The one showing a high potential is used for the positive electrode, and the one showing a low potential is used for the negative electrode to form an arbitrary battery.

[0044] As Figure 1 (a)(b) shows, the positive electrode 2 and the negative electrode 1 are each composed of a metal porous body having mutually continuous pore portions (communicating pore portions), and include a positive electrode current collector 20 and a negative electrode current collector 10 having a substantially rectangular shape in plan view. In addition, hereinafter, Figure 1 the plan view of (b) is set as the XY plane, and Figure 1 the cross-sectional view of (a) is set as the XZ plane. That is, the in-plane direction when the electrode is regarded as a plate shape is the XY direction. The out-of-plane direction is the Z direction.

[0045] In Figure 1 (a) in the stacked state, reduced-diameter tab converging portions 12, 22 extend from one end portion of the positive electrode current collector 20 and the negative electrode current collector 10, and linear tabs 13, 23 are connected to the reduced-diameter end portions thereof. In Figure 1 this, the tab converging portions 12, 22 are regions where the composite material is not filled.

[0046] Electrode composite materials (positive electrode composite materials) 28 and electrode composite materials (negative electrode composite materials) 18 containing electrode active materials are respectively filled and disposed in the pore portions of the positive electrode current collector 20 and the negative electrode current collector 10 to form composite material filling regions 11, 21. Conversely, in the present invention, there are composite material non-filling regions in the current collector where the electrode composite materials are not filled and disposed. This will be described below.

[0047] (Current collector)

[0048] As Figure 2As schematically shown, the positive electrode current collector 20 and the negative electrode current collector 10 of the structures constituting the positive electrode and the negative electrode are made of a metal porous body having mutually continuous pore portions V1 (negative electrode pore portion) and V2 (positive electrode pore portion). Since the positive electrode current collector 20 and the negative electrode current collector 10 have mutually continuous pore portions, thus, the positive electrode composite material 28 and the negative electrode composite material 18 containing the electrode active material can be filled respectively inside the pore portions, and the amount of the electrode active material per unit area of the electrode layer can be increased. As the above-mentioned metal porous body, as long as it has mutually continuous pore portions, there is no particular limitation, and examples thereof include foamed metals having pore portions formed by foaming, metal meshes, expanded metals, punched metals, non-woven metal fabrics, and the like.

[0049] As the metal used in the metal porous body, as long as it has conductivity, there is no particular limitation, and examples thereof include nickel, aluminum, stainless steel, titanium, copper, silver, and the like. Among these, as the current collector constituting the positive electrode, foamed aluminum, foamed nickel, and foamed stainless steel can be preferably used; as the current collector constituting the negative electrode, foamed copper and foamed stainless steel can be preferably used.

[0050] By using the positive electrode current collector 20 and the negative electrode current collector 10 of the metal porous body, thus, the amount of the active material per unit area of the electrode can be increased, and as a result, the volume energy density of the lithium ion secondary battery can be improved. In addition, since the immobilization of the positive electrode composite material 28 and the negative electrode composite material 18 becomes easy, therefore, different from the electrode using the conventional metal foil as the current collector, when thickening the electrode composite material layer, it is not necessary to thicken the coating slurry for forming the electrode composite material layer. Therefore, the binder such as the organic high molecular compound required for thickening can be reduced. Thus, the capacity per unit area of the electrode can be increased, and the high capacity of the lithium ion secondary battery can be achieved.

[0051] (Electrode composite material)

[0052] The positive electrode composite material 28 and the negative electrode composite material 18 are respectively disposed in the pore portions V1 (negative electrode pore portion) and V2 (positive electrode pore portion) formed inside the positive electrode current collector 20 and the negative electrode current collector 10. The positive electrode composite material 28 and the negative electrode composite material 18 must respectively contain a positive electrode active material and a negative electrode active material.

[0053] (Electrode active material)

[0054] As the positive electrode active material, as long as it can occlude and release lithium ions, there is no particular limitation, and examples thereof include LiCoO2, Li(Ni 5 / 10 Co 2 / 10 Mn 3 / 10 )O2, Li(Ni 6 / 10 Co 2 / 10 Mn 2 / 10 )O2, Li(Ni8 / 10 Co 1 / 10 Mn 1 / 10 )O2, Li(Ni 0.8 Co 0.15 Al 0.05 )O2, Li(Ni 1 / 6 Co 4 / 6 Mn 1 / 6 )O2, Li(Ni 1 / 3 Co 1 / 3 Mn 1 / 3 )O2, LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, sulfur, etc.

[0055] As the negative electrode active material, as long as it can occlude and release lithium ions, there is no particular limitation, and examples thereof include metallic lithium, lithium alloys, metal oxides, metal sulfides, metal nitrides, Si, SiO, and carbon materials such as artificial graphite, natural graphite, hard carbon, and soft carbon.

[0056] (Other components)

[0057] The electrode composite material may optionally contain other components in addition to the electrode active material and the ion conductive particles. As the other components, there is no particular limitation as long as they are components that can be used in the production of a lithium ion secondary battery. Examples thereof include conductive aids, binders, etc. As the conductive aid for the positive electrode, acetylene black, etc. can be exemplified; as the binder for the positive electrode, polyvinylidene fluoride, etc. can be exemplified. As the binder for the negative electrode, sodium carboxymethyl cellulose, styrene-butadiene rubber, sodium polyacrylate, etc. can be exemplified.

[0058] (Manufacturing methods of the positive electrode and the negative electrode)

[0059] The positive electrode 2 and the negative electrode 1 can be obtained by filling the electrode composite material into the pores of a metal porous body having mutually continuous pores as a current collector. First, the electrode active material, and optionally a binder and an additive, are uniformly mixed by a conventionally known method to obtain an electrode composite material composition adjusted to a specified viscosity, preferably in a slurry form.

[0060] Subsequently, the above electrode composite material composition is used as the electrode composite material and filled into the pores of a metal porous body as a current collector. The method of filling the electrode composite material into the current collector is not particularly limited, and examples thereof include a method of using a plunger die coater to apply pressure and fill the inside of the pores of the current collector with a slurry containing the electrode composite material. In addition to the above, an impregnation method can also be used to impregnate the ion conductor layer into the inside of the metal porous body.

[0061] (Electrolyte layer)

[0062] In this embodiment, the solid electrolyte layer 4 is used. However, in the present invention, a solid or gel electrolyte, i.e., a solid electrolyte, may be provided, or a liquid electrolyte in which an electrolyte is dissolved in a non-aqueous solvent may be used.

[0063] The solid electrolyte is not particularly limited, and examples thereof include sulfide-based solid electrolyte materials, oxide-based solid electrolyte materials, nitride-based solid electrolyte materials, halide-based solid electrolyte materials, etc. As the sulfide-based solid electrolyte material, for example, in the case of a lithium-ion battery, LPS-based halogens (Cl, Br, I), and Li2S-P2S5, Li2S-P2S5-LiI, etc. can be cited. In addition, the description of "Li2S-P2S5" above refers to a sulfide-based solid electrolyte material made from a raw material composition containing Li2S and P2S5, and the same applies to other descriptions. As the oxide-based solid electrolyte material, for example, in the case of a lithium-ion battery, sodium superionic conductor (NASICON)-type oxides, garnet-type oxides, perovskite-type oxides, etc. can be cited. As the NASICON-type oxide, an oxide containing Li, Al, Ti, P, and O (e.g., Li 1.5 Al 0.5 Ti 1.5 (PO4)3) can be cited. As the garnet-type oxide, an oxide containing Li, La, Zr, and O (e.g., Li7La3Zr2O 12 ) can be cited. As the perovskite-type oxide, an oxide containing Li, La, Ti, and O (e.g., LiLaTiO3) can be cited.

[0064] The electrolyte dissolved in the non-aqueous solvent is not particularly limited, and examples thereof include LiPF6, LiBF4, LiClO4, LiN(SO2CF3), LiN(SO2C2F5)2, LiCF3SO3, LiC4F9SO3, LiC(SO2CF3)3, LiF, LiCl, LiI, Li2S, Li3N, Li3P, Li 10 GeP2S 12 (LGPS), Li3PS4, Li6PS5Cl, Li7P2S8I, Li x PO y N z (x = 2y + 3z - 5, LiPON), Li7La3Zr2O 12 (LLZO), Li 3x La 2 / 3-x TiO3(LLTO), Li 1+x Al x Ti 2-x(PO4)3(0 ≦ x ≦ 1, LATP), Li 1.5 Al 0.5 Ge 1.5 (PO4)3(LAGP), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 、Li 1+x+y Al x (Ti, Ge) 2-x Si y P 3-y O 12 、Li 4- 2x Zn x GeO4 (LISICON), etc. The above can be used alone or in combination of two or more.

[0065] As the non-aqueous solvent contained in the electrolyte, there is no particular limitation, and aprotic solvents such as carbonates, esters, ethers, nitriles, sulfones, lactones, etc. can be listed. Specifically, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), 1,2-dimethoxy ethane (DME), 1,2-diethoxy ethane (DEE), tetrahydrofuran (THF), 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, acetonitrile (AN), propionitrile, nitromethane, N,N-dimethylformamide (DMF), dimethyl sulfoxide, sulfolane, γ-butyrolactone, etc. can be listed. The above can be used alone or in combination of two or more.

[0066] (Separator)

[0067] The lithium ion secondary battery of this embodiment may also include a separator, especially in the case of using a liquid electrolyte. The separator is located between the positive electrode and the negative electrode. Its material, thickness, etc. are not particularly limited, and known separators such as polyethylene and polypropylene that can be used in lithium ion secondary batteries can be applied.

[0068] <Composite Material Filled Region and Composite Material Unfilled Region>

[0069] Next, the composite material filled region 11(21) and the composite material unfilled region 15(25) in the current collector, which are features of the present invention, will be described. The figure numbers in parentheses are examples for the negative electrode.

[0070] As the above prior art, as Figure 7 shown, in Figure 1 (a)(b), if the parts of the positive electrode current collector 20 constituting the positive electrode 2 and the negative electrode current collector 10 constituting the negative electrode 1 excluding the tab converging part 12(22) are removed, the overall shape is approximately a rectangular parallelepiped.

[0071] Therefore, in the figure, there are corner parts A at the positions circled by circles. In this embodiment, there are four corner parts A at the four corners of the upper surface in the XY plane of the electrode, and four corner parts A at the four corners of the lower surface, for a total of eight corner parts A. In addition, there are corner parts accompanied by the start of diameter reduction of the tab converging part 12 in the X direction at the corner parts on the tab converging part 12 side, so these also constitute the corner parts in the present invention. In the present invention, the so-called "corner part" not only refers to the top part formed by at least three faces, i.e., the corner part, but also the case where the top part is a curved surface with an R shape is equivalent to the corner part in the present invention.

[0072] In Figure 1 (a)(b), at this corner part A, the top part of the composite material filled region 11(21) containing the electrode composite materials 18, 28 is chamfered to form a curved surface part 26 with an R shape. As a result, a composite material unfilled region 15(25) is formed at the corner part A. The positive electrode current collector 20 is composed of a composite material filled region 21, a composite material unfilled region 25, and a tab converging part 22, and the negative electrode current collector 10 is composed of a composite material filled region 11, a composite material unfilled region 15, and a tab converging part 12.

[0073] The composite material unfilled region 15(25) is formed by a structure body, which is only a current collector with a three-dimensional mesh structure space. Therefore, compared with the composite material filled region 11(21) filled with an electrode composite material with a large elastic modulus, the elastic modulus of the composite material unfilled region 15(25) is smaller. As Figure 1 (a)(b) shows, when the plate P clamps and punches from the up and down directions (Z direction), the composite material filled region 11(21) is rolled along the arrow direction in the XY plane of Figure 1 (b), and the stress will concentrate at the corner part A. At this time, the composite material unfilled region 15(25) will act as a buffer layer, so it can effectively prevent the electrode from cracking.

[0074] The unfilled region 15(25) of the composite material can be provided on both the positive electrode 2 and the negative electrode 1 as in this embodiment, or can be provided only on the necessary parts of either the positive electrode 2 or the negative electrode 1. In addition, it can be provided at all the corner portions A as in this embodiment, or can be provided only at one or more specified corner portions. Since stress tends to concentrate at the corner portions of the current collector on the side opposite to the tab converging portion in a plan view, it is preferable to form it at least at this corner portion.

[0075] In addition, it can also be like Figure 1 the unfilled region 15 of the negative electrode 1 in (a), and the unfilled region 15 of the composite material can be formed in such a manner that the upper and lower two corner portions located on the same straight line in the Z direction are continuous with each other.

[0076] In addition, it is preferable that the total area of the negative electrode composite material filled region 11 and the unfilled region 15 of the composite material is substantially the same as the total area of the positive electrode composite material filled region 21 and the unfilled region 25 of the composite material. By making the two areas the same, the surface pressure of the positive electrode and the negative electrode becomes uniform, so that the bias of stress can be suppressed to prevent cracking and the like. In addition, in order to prevent Li electrodeposition, as Figure 1 shown, it is preferable that the area of the positive electrode composite material filled region 21 is smaller than the area of the negative electrode composite material filled region 11 facing each other.

[0077] In addition, in the unfilled region 15(25) of the composite material, a highly elastic filler having an elastic modulus smaller than that of the electrode composite material, that is, a soft one, can also be filled. At this time, if the highly elastic filler is at least one selected from an insulating material, a reinforcing material, and a heat insulating material, a solid battery can be provided, which can improve the protection function of the corner portion of the current collector in terms of electricity, strength, and heat, and has higher durability. As a specific example of the highly elastic filler, resins and elastomers having an elastic modulus smaller than that of the electrode composite material can be exemplified. As the highly elastic filler, the above solid electrolyte can also be contained. Figure 1 (a) is an example in which a highly elastic filler is filled in the unfilled region 15(25) of the composite material. As described below, it is distinguished from the example where the highly elastic filler is not filled by the hatched lines shown in the figure.

[0078] In addition, the highly elastic filler can be filled not only in the unfilled region 15(25) of the corner portion, but also in the tab converging portion 12. The negative electrode 1 arranged at Figure 1 the uppermost part of (a) is an example where the highly elastic filler is not filled in the tab converging portion 12, and the negative electrode 1 arranged at Figure 1 the lowermost part of (a) is an example where the highly elastic filler is filled in the tab converging portion 12, and the two are distinguished by hatched lines.

[0079] [Second Embodiment]

[0080] Figure 3 It is a schematic cross-sectional view of the second embodiment of the lithium-ion secondary battery of the present invention. Figure 4 (a) is Figure 3 the (a) plan view of the positive electrode in Figure 4 (b) is Figure 4 (a) The B-B cross-sectional view of (a). Hereinafter, for the same structure as the first embodiment, the same reference numerals are assigned and the description thereof is omitted.

[0081] In this embodiment, the difference from the first embodiment is that there are unfilled regions of the composite material not only in the corner portions but also in the outer peripheral region of the current collector. Thereby, a solid battery can be provided which can relieve the stress applied from the outside of the outer peripheral region in addition to the corner portions of the current collector, and has higher durability.

[0082] As Figure 4 shown by the negative electrode 1b in (a) and (b), the unfilled regions of the composite material in this embodiment are formed in a circumferential shape on the four sides of the negative electrode 1b with 15a, 15b, 15c, and 15d. As Figure 3 shown, the lithium-ion secondary battery 200 is packaged with an outer packaging film 50 after stacking a plurality of electrode monomers. In the case of assuming in-vehicle use, etc., the impact of a collision with a vehicle from the side and the vibration during driving on a rough road are mostly applied as Figure 3 external forces in the arrow direction, from the outer peripheral direction of the XY plane of the electrode. At this time, the unfilled regions 15a, 15b, 15c, and 15d of the composite material can function as a circumferential buffer layer, and thus can effectively prevent the electrodes from breaking.

[0083] Figure 3 , Figure 4 is an example in which a highly elastic filler is not filled in the unfilled regions 15a, 15b, 15c, and 15d of the composite material, but in this embodiment, a highly elastic filler may also be filled in the unfilled regions 15a, 15b, 15c, and 15d in the same manner as in the first embodiment.

[0084] In addition, a highly elastic filler may also be filled in the space 51 between the outer packaging film 50 and the ear converging portion 12 of the positive electrode 2 and the negative electrode 1.

[0085] [Third Embodiment]

[0086] Figure 5 It is a schematic cross-sectional view of the third embodiment of the lithium-ion secondary battery of the present invention. Figure 6 is Figure 5 the (a) plan view of the positive electrode, (b) the C-C cross-sectional view, and (c) a modified example of the C-C cross-sectional view in

[0087] In this embodiment, the difference from the first embodiment is that not only in the corner portions, but also the unfilled regions of the composite material exist as the intermediate layer in the aforementioned thickness direction of the current collector. Thus, a solid battery can be provided which, in addition to the corner portions of the current collector, can also utilize the intermediate layer to relieve the stress applied in the out-of-plane thickness direction of the current collector, resulting in higher durability.

[0088] As Figure 6 shown by the negative electrode 1c of

[0089] , in the lithium-ion secondary battery 300 of this embodiment, in addition to the unfilled regions 15(25) of the composite material in the corner portions, the unfilled regions 15e of the composite material also form as an intermediate layer. The intermediate layer exists in a planar shape with a specified thickness on the XY plane and is configured to be sandwiched by the layers of the upper and lower composite material filled regions 11(21). This structure can be formed by impregnating the electrode composite material with a specified viscosity from the up and down directions of the current collector. Figure 6 (b) The intermediate layer 15e can be configured to have the same shape and the same area as the composite material filled regions 11(21), or can extend into the tab convergence portion 12 as in Figure 6 (c). In addition, not only one layer of the intermediate layer can be configured, but also any number of intermediate layers can be configured.

[0090] Figure 5 , Figure 6 This is an example where the highly elastic filler is not filled in the unfilled regions 15, 15e, 15f of the composite material. However, in this embodiment, similar to the first embodiment, the highly elastic filler can also be filled in the unfilled regions 15, 15e, 15f of the composite material.

[0091] As Figure 5 shown, when the lithium-ion secondary battery 300 repeatedly absorbs and releases lithium, it will repeatedly expand and contract in volume in the Z direction in the figure. At this time, the unfilled regions 15e, 15f of the composite material in the intermediate layer act as a buffer layer as shown by the arrows in the figure, and can effectively prevent the electrodes from cracking.

[0092] Above, the preferred embodiments of the present invention have been described, but the content of the present invention is not limited to the above embodiments and can be appropriately changed.

[0093] Reference numerals

[0094] 1, 1b, 1c: Negative electrode

[0095] 10: Current collector (negative electrode current collector)

[0096] 11: Composite material filled region

[0097] 12: Tab Convergence Section

[0098] 13: Tab

[0099] 15: Composite Material Unfilled Area

[0100] 15a, 15b, 15c, 15d: Composite Material Unfilled Area

[0101] 15e, 15f: Composite Material Unfilled Area

[0102] 16: Curved Surface Portion

[0103] 18: Electrode Composite Material (Negative Electrode Composite Material)

[0104] 2, 2b, 2c: Positive Electrode

[0105] 20: Current Collector (Positive Electrode Current Collector)

[0106] 21: Composite Material Filled Area

[0107] 22: Tab Convergence Section

[0108] 23: Tab

[0109] 25: Composite Material Unfilled Area

[0110] 26: Curved Surface Portion

[0111] 28: Electrode Composite Material (Positive Electrode Composite Material)

[0112] 4: Solid Electrolyte Layer

[0113] 51: Space

[0114] V1, V2: Hole Portion

[0115] A: Corner Portion

[0116] 100, 200, 300: Lithium-Ion Secondary Battery

Claims

1. An electrode, which is an electrode for a lithium-ion secondary battery, The aforementioned electrode includes: a current collector, which has a specific thickness and is a metal porous body having at least one corner portion when observed three-dimensionally; and an electrode composite material, which is filled in the pores of the aforementioned metal porous body; In the aforementioned current collector, a composite material filling region and a non-composite material filling region exist in the aforementioned corner portion of the current collector. The composite material filling region is filled with the aforementioned electrode composite material, and the non-composite material filling region is not filled with the aforementioned electrode composite material or is filled with a highly elastic filler having a smaller elastic modulus than the aforementioned electrode composite material. Among them, In the aforementioned corner portion of the current collector, the aforementioned composite material filling region is curved.

2. An electrode, which is an electrode for a lithium-ion secondary battery, The aforementioned electrode includes: a current collector, which has a specific thickness and is a metal porous body having at least one corner portion when observed three-dimensionally; and an electrode composite material, which is filled in the pores of the aforementioned metal porous body; In the aforementioned current collector, a composite material filling region and a non-composite material filling region exist in the aforementioned corner portion of the current collector. The composite material filling region is filled with the aforementioned electrode composite material, and the non-composite material filling region is filled with a highly elastic filler having a smaller elastic modulus than the aforementioned electrode composite material. Among them, The aforementioned highly elastic filler is at least one selected from an insulating material, a reinforcing material, and a heat insulating material.

3. An electrode, which is an electrode for a lithium-ion secondary battery, The aforementioned electrode includes: a current collector, which has a specific thickness and is a metal porous body having at least one corner portion when observed three-dimensionally; and an electrode composite material, which is filled in the pores of the aforementioned metal porous body; In the aforementioned current collector, a composite material filling region and a non-composite material filling region exist in the aforementioned corner portion of the current collector. The composite material filling region is filled with the aforementioned electrode composite material, and the non-composite material filling region is not filled with the aforementioned electrode composite material or is filled with a highly elastic filler having a smaller elastic modulus than the aforementioned electrode composite material. Among them, The aforementioned non-composite material filling region also exists as an intermediate layer in the aforementioned thickness direction of the current collector.

4. The electrode according to any one of claims 1 to 3, wherein, The aforementioned non-composite material filling region also exists in the outer peripheral region of the current collector.

5. A lithium-ion secondary battery, which uses the electrode according to any one of claims 1 to 3 as a positive electrode and a negative electrode, and the aforementioned positive electrode, electrolyte layer, and aforementioned negative electrode are alternately arranged. And in the aforementioned lithium-ion secondary battery, The areas of the aforementioned current collectors adjacent to and facing each other are the same.

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