Short-circuit-proof all-solid-state battery

Abstract

The utility model provides an all-solid-state battery capable of preventing short circuit, and belongs to the technical field of all-solid-state batteries. The all-solid-state battery comprises a solid electrolyte layer, a positive electrode and a negative electrode, the positive electrode and the negative electrode are alternately stacked, the solid electrolyte layer is arranged between the positive electrode and the negative electrode, an insulating layer is arranged on a positive electrode current collector on the side where a tab is located and on the periphery of a positive electrode material area on the opposite side, and insulating tapes are pasted on the upper and lower sides of the positive electrode without the insulating layer. According to the utility model, the gluing ion / electronic insulating layers are arranged at the peripheries of the lugs and the opposite sides of the lugs in the positive electrode material area, and the insulating tapes are adhered to the upper and lower surfaces of the two sides of the positive electrode without the insulating layers, so that short circuit caused by shearing of the edges of the positive and negative electrode pieces under high voltage can be effectively prevented, and the safety and the reliability of the battery are improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the all solid state battery technical field, and specifically relates to a short-circuit-preventing all solid state battery. BACKGROUND

[0002] With the increasing demand for energy and the increasingly serious environmental problems, the development of new energy vehicles has become the focus of global attention. As a new type of battery with high energy density, long cycle life and high safety, all solid state battery is considered to be the ideal power source for future electric vehicles.

[0003] However, the development of all solid state batteries still faces some challenges, one of which is that the shear of the positive and negative electrode edges under high pressure may cause battery short circuit, thereby affecting the performance and reliability of the battery.

[0004] In the structure of all solid state batteries, a solid electrolyte layer is provided between the positive and negative electrodes. Due to the difference in size between the positive and negative electrode sheets and the electrolyte film ("negative electrode covering positive electrode" structure, i.e. the area of the negative electrode sheet is larger than that of the positive electrode sheet, and the positive and negative material layers are stacked in the middle so that the width and length of the positive electrode sheet are smaller than those of the negative electrode sheet), the positive electrode sheet edge will generate shear force on the electrolyte layer when stacked and subjected to isostatic pressing or flat pressing, thereby easily causing the positive electrode sheet edge to pierce the electrolyte layer and come into contact with the negative electrode, causing battery short circuit, thereby affecting the performance and reliability of the battery. Moreover, as the number of stacks increases, in order to better reduce the impedance of the multi-interface battery, the pressing pressure and pressing time are appropriately increased, which is more likely to cause indentation and damage to the electrolyte layer and the negative electrode sheet.

[0005] Therefore, it is of great practical significance to develop a simple and effective short-circuit-preventing all solid state battery structure. INVENTION CONTENTS

[0006] To at least solve one of the problems in the prior art, the utility model provides a short-circuit-preventing all solid state battery, which is provided with an ion / electron insulation zone on the periphery of the positive active area on the side of the positive tab and the opposite side, and insulating tape is attached to the upper and lower surfaces of the positive electrode on both sides without insulation zone, thereby effectively preventing battery short circuit and improving the yield and safety of the battery.

[0007] In order to achieve the above-mentioned purposes of the utility model, the following technical solutions are adopted:

[0008] The utility model provides a short-circuit-preventing all solid state battery, which comprises a solid electrolyte layer and positive and negative electrode sheets alternately stacked with the solid electrolyte layer between the positive and negative electrode sheets, and the solid electrolyte layer and the negative electrode sheet are equal in size.

[0009] The positive electrode sheet includes a positive electrode current collector and a coating layer on both sides of the positive electrode current collector, the coating layer includes a positive electrode material area and an insulating material area on both sides of the positive electrode material area, and the two sides are the side where the tab is located and the opposite side; the size of the positive electrode sheet (the positive electrode material area and the insulating material area) is greater than the size of the solid electrolyte layer in the direction perpendicular to the side where the tab is located and the opposite side, and the size of the positive electrode sheet (the positive electrode material area) is greater than or equal to the size of the solid electrolyte layer in the direction of the side where the tab is located and the opposite side;

[0010] The positive electrode sheet is pasted with insulating adhesive tape on the upper and lower surfaces of the two sides in the direction perpendicular to the side where the tab is located and the opposite side, and the insulating adhesive tape covers the edge of the positive electrode sheet in the width direction; after the lamination is pressed, the insulating adhesive tape is pressed into the adjacent solid electrolyte layer.

[0011] The solid electrolyte structure is described in detail as follows:

[0012] The cross-sectional structure of the full-solid-state battery is shown in the length direction of the insulating material area. Figure 1 The cross-sectional structure of the full-solid-state battery is shown in the length direction of the insulating material area. Figure 2 The surface structure of the positive electrode sheet is shown in the length direction of the insulating material area. Figure 3

[0013] The full-solid-state battery includes a solid electrolyte layer 3 and positive electrode sheets 1 and negative electrode sheets 2 which are alternately stacked and the solid electrolyte layer 3 is between the positive electrode sheets 1 and the negative electrode sheets 2.

[0014] The positive electrode sheet 1 includes a positive electrode current collector 11, and a coating layer (a positive electrode material area 12 and an insulating material area 13) is arranged on the front and back surfaces of the positive electrode current collector 11, and the insulating material area 13 is located on the periphery of the positive electrode material area 12 on the side where the tab is located and the opposite side, that is, two long strip-shaped areas, wherein the size of the solid electrolyte layer 3 is equal to the size of the negative electrode sheet 2, in the direction perpendicular to the side where the tab is located and the opposite side, the length L1 of the coating layer (the length L2 of the positive electrode material area 12 + the width of the two insulating material areas 13 in this direction) is greater than the length of the solid electrolyte layer 3 in this direction, and in the direction of the side where the tab is located and the opposite side, the length L3 of the coating layer (the length of the positive electrode material area 12 = the length of the insulating material area 13 in this direction) is greater than or equal to the length of the solid electrolyte layer 3 in this direction.

[0015] After the positive electrode sheet is formed, insulating adhesive tape 4 is pasted on the upper and lower surfaces of the two sides of the positive electrode sheet without the insulating material area, and in the direction of the side where the tab is located and the opposite side (that is, the width direction of the insulating adhesive tape), the insulating adhesive tape 4 partially (or entirely) covers the edge of the positive electrode sheet, that is, L4 < L3, L5 ≥ L3. L2 ≤ the length of the insulating adhesive tape 4 ≤ L1 (the case where the length of the insulating adhesive tape and L1 are equal in the above-mentioned (2)). Figure 3

[0016] ​​The schematic cross-sectional structure diagram along the direction of the insulating tape after being pressed is as shown in Figure 4 and the schematic cross-sectional structure diagram along the direction of the insulating material area is as shown in Figure 5 When the insulating material area is further compressed along with the overall structure, the insulating tape will also be pressed into the adjacent solid electrolyte layer (only a little indentation).

[0017] Insulating material area:

[0018] The material of the insulating material area of the present utility model is at least one of PVDF and its modified materials, PAN and its modified materials, PI and its modified materials, natural rubber NR, styrene-butadiene rubber SBR, butyl rubber IIR, hydrogenated nitrile rubber HNBR, ethylene-propylene rubber EPDM, nitrile rubber NBR, chloroprene rubber CR, silicone rubber, polyurethane, styrene-butadiene block copolymer rubber SBS and its modified material SEBS, polyisobutylene rubber PIB, or a mixture thereof with inorganic fillers.

[0019] In some embodiments, when not under force, the thickness L of the insulating material area and the thickness M of the positive electrode material area satisfy the following relationship: L - 50μm ≤ M ≤ L + 30μm, and the units of L and M are μm.

[0020] When not under force, the thickness of the insulating material area can be slightly larger, slightly smaller, or equal to the thickness of the positive electrode material area. When the thickness of the insulating material area is slightly larger than or equal to the thickness of the positive electrode material area (i.e., L ≥ M, L - M ≤ 50μm), after being pressed, both the insulating material area and the positive electrode material area are compressed, but the thickness of the insulating material area cannot be much higher than the thickness of the positive electrode material area. This is because if it is higher than 50μm, during the rolling of the positive electrode layer / or the isostatic pressing of the battery cell, it will cause poor contact between the positive electrode layer and the electrolyte layer, and even cause the positive electrode layer to break, thus affecting the battery performance; when the thickness of the insulating material area is slightly smaller than the thickness of the positive electrode material area (i.e., L < M, M - L ≤ 30μm), after being pressed, the positive electrode material area will also be slightly compressed. To ensure that it can be pressed onto the insulating material area, the thickness of the insulating material area cannot be much lower than the thickness of the positive electrode material area.

[0021] This design can avoid the shearing effect of the positive electrode active material area on the electrolyte layer, also avoid the fracture of the negative electrode sheet during the pressurization process of the battery cell due to the thickness difference, and at the same time will not have too much impact on the energy density of the battery.

[0022] In some embodiments, the width of the insulating material area = (L1 - L2) / 2 is 0.5 - 10mm.

[0023] Insulating tape:

[0024] The material of the insulating tape of the present utility model is at least one of PI, PE, PP, PET, and PEEK.

[0025] In some embodiments, the thickness of the insulating tape is 1-20 μm.

[0026] In some embodiments, the width of the insulating tape = (L5-L4) / 2 is 0.5-10 mm, preferably the insulating tape covers the edge of the positive electrode sheet completely.

[0027] The positive electrode current collector and the positive electrode material region of the positive electrode sheet are both less than 2000 mm in length and width.

[0028] In some embodiments, the positive electrode current collector is an aluminum foil; the positive electrode material region comprises the following components by mass percentage: positive electrode active material 70-94%, conductive agent 1-3%, binder 1-3%, and sulfide electrolyte 4-28%.

[0029] In some embodiments, the positive electrode active material is at least one selected from the group consisting of ternary material, lithium iron phosphate, lithium cobaltate, lithium manganese iron phosphate, lithium-rich manganese-based material, sulfur positive electrode material (such as a composite of sulfur and carbon, or a composite of sulfur and organic matter).

[0030] In some embodiments, the conductive agent is at least one selected from the group consisting of acetylene black, Super P, Super S, 350G, carbon fiber VGCF, carbon nanotube CNTs, ketjen black, graphite conductive agent (such as KS-6, KS-15, SFG-6, SFG-15), and graphene.

[0031] In some embodiments, the binder is at least one selected from the group consisting of polyvinylidene fluoride PVDF and modified materials thereof, polytetrafluoroethylene PTFE and modified materials thereof, polyethylene oxide PEO, polypropylene carbonate PPC, polyethylene carbonate PEC, polytrimethylene carbonate PTMC, polyvinyl alcohol PVA, sodium carboxymethyl cellulose CMC, polyolefin (polyethylene, polypropylene, and copolymers thereof), hydrogenated styrene-butadiene block copolymer SEBS, nitrile rubber NBR, modified SBR, fluorinated rubber, and polyurethane.

[0032] In some embodiments, the sulfide electrolyte is at least one selected from the group consisting of binary sulfide electrolyte, ternary sulfide electrolyte, and argyrodite-type sulfide electrolyte, and is preferably lithium phosphorus sulfide chloride (Li6PS5Cl).

[0033] The thickness of the positive electrode sheet can be 30-450 μm.

[0034] Negative electrode sheet:

[0035] The negative electrode sheet comprises a negative electrode current collector and a negative electrode material layer on both sides, and the negative electrode material layer comprises the following components by mass percentage: negative electrode active material 60-90%, conductive agent 1-3%, binder 1-3%, and sulfide electrolyte 4-38%.

[0036] In some embodiments, the negative current collector is a copper foil.

[0037] In some embodiments, the negative active material is at least one selected from carbon materials (such as conductive carbon black, carbon nanotube, graphene, fullerene, carbon nanofiber), silicon negative materials (such as silicon monoxide, nano-silicon), tin negative materials (such as tin-carbon negative materials), lithium metal negative materials, lithium-free negative materials (such as silver-carbon negative materials).

[0038] In some embodiments, the conductive agent is at least one selected from acetylene black, Super P, Super S, 350G, carbon fiber VGCF, carbon nanotube CNTs, ketjen black, graphite conductive agent (such as KS-6, KS-15, SFG-6, SFG-15), and graphene.

[0039] In some embodiments, the binder is at least one selected from polyvinylidene fluoride PVDF and modified materials thereof, polytetrafluoroethylene PTFE and modified materials thereof, polyethylene oxide PEO, polypropylene carbonate PPC, polyethylene carbonate PEC, polytrimethylene carbonate PTMC, polyvinyl alcohol PVA, sodium carboxymethyl cellulose CMC, polyolefins (polyethylene, polypropylene and copolymers thereof), hydrogenated styrene-butadiene block copolymer SEBS, nitrile rubber NBR, modified SBR, fluorinated rubber, polyurethane.

[0040] In some embodiments, the sulfide electrolyte is at least one selected from binary sulfide electrolyte, ternary sulfide electrolyte, and argyrodite-type sulfide electrolyte, preferably lithium phosphorus sulfide chloride (Li6PS5Cl).

[0041] The thickness of the negative electrode sheet can be 20-400 μm.

[0042] The solid electrolyte layer includes the following components in mass percentage: solid electrolyte 95-99.5% and binder 0.5-5%.

[0043] In some embodiments, the solid electrolyte is at least one selected from sulfide electrolyte, oxide electrolyte, chloride electrolyte, polymer electrolyte; preferably argyrodite-type solid electrolyte (Li6PS5X, X = Cl, Br, I), for example, lithium phosphorus sulfide chloride (Li6PS5Cl).

[0044] In some embodiments, the solid electrolyte is at least one selected from sulfide electrolyte, oxide electrolyte, chloride electrolyte, polymer electrolyte; preferably argyrodite-type solid electrolyte (Li6PS5X, X = Cl, Br, I), for example, lithium phosphorus sulfide chloride (Li6PS5Cl).

[0045] In some embodiments, the binder is at least one selected from polyvinylidene fluoride (PVDF) and modified materials thereof, polytetrafluoroethylene (PTFE) and modified materials thereof, polyethylene oxide (PEO), polypropylene carbonate (PPC), polyethylene carbonate (PEC), polytrimethylene carbonate (PTMC), polyvinyl alcohol (PVA), sodium carboxymethyl cellulose (CMC), polyolefins (polyethylene, polypropylene and copolymers thereof), hydrogenated styrene-butadiene block copolymer (SEBS), nitrile rubber (NBR), modified SBR, fluorinated rubber, and polyurethane.

[0046] The thickness of the solid electrolyte layer can be 5-200 μm.

[0047] The method for preparing the short-circuit prevention all-solid-state battery described above comprises the following steps:

[0048] (a) preparing a solid electrolyte layer, coating negative electrode material slurry on both sides of the negative electrode current collector, drying to obtain a negative electrode sheet with negative electrode material layers on both sides, and cutting to make the size of the solid electrolyte layer equal to that of the negative electrode sheet;

[0049] (b) coating positive electrode material slurry on both sides of the positive electrode current collector, drying to form positive electrode material zones, and then coating insulating material slurry on the periphery of the positive electrode material zones on the side where the tabs are located and on the opposite side, drying to form insulating material zones (or coating positive electrode material slurry in the middle and insulating material slurry on the edges at the same time, drying to form a positive electrode sheet containing positive electrode material zones and insulating material zones), cutting to make the size of the coating layer (positive electrode material zone and insulating material zone) in the direction perpendicular to the side where the tabs are located and the opposite side greater than that of the solid electrolyte layer, and the size of the coating layer (positive electrode material zone) in the direction of the side where the tabs are located and the opposite side greater than or equal to that of the solid electrolyte layer, to obtain a positive electrode sheet; pasting insulating adhesive tape on the upper and lower sides of the positive electrode sheet in the direction perpendicular to the side where the tabs are located and the opposite side, so that the insulating adhesive tape covers the edges of the positive electrode sheet completely or partially in the width direction, to obtain a composite positive electrode sheet;

[0050] (c) stacking the negative electrode sheet, the solid electrolyte layer, the composite positive electrode sheet, the solid electrolyte layer, and the negative electrode sheet in this order to obtain a battery cell; and performing pressure treatment on the battery cell.

[0051] The pressure treatment can be performed by one of isostatic pressing, flat plate pressing, and roller pressing, at a temperature of 0-1000°C for 0.5-30 minutes at a pressure of 3-1000 MPa. The pressure treatment can make the contact between the components of the battery more compact, thereby improving the conductivity and stability of the battery.

[0052] Advantages:

[0053] The utility model discloses a positive pole piece surface structure schematic diagram, the positive pole piece surface structure schematic diagram comprises positive pole piece, negative pole piece, solid electrolyte layer and insulating adhesive tape, and the positive pole piece is provided with the insulating adhesive tape on the upper surface and the lower surface of the other two sides of the positive pole material area.

[0054] The utility model has been described in the foregoing detailedly, but the above-mentioned implementation is only illustrative in essence, and is not intended to limit the utility model. In addition, this article is not limited by any theory described in the foregoing prior art or utility model content or the following embodiment. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 It is full solid state battery laminated assembly pressure leading edge insulating adhesive tape direction's electric core cross section structure schematic diagram of the utility model;

[0056] Figure 2 It is full solid state battery laminated assembly pressure leading edge insulating material area direction's electric core cross section structure schematic diagram of the utility model;

[0057] Figure 3 It is positive pole piece surface structure schematic diagram;

[0058] Figure 4 It is full solid state battery laminated assembly pressure trailing edge insulating adhesive tape direction's electric core cross section structure schematic diagram of the utility model;

[0059] Figure 5 It is full solid state battery laminated assembly pressure trailing edge insulating material area direction's electric core cross section structure schematic diagram of the utility model;

[0060] Fig. 1-Positive pole piece;11-Positive pole current collector;12-Positive pole material area;13-Insulating material area;2-Negative pole piece;3-Solid electrolyte layer;4-Insulating adhesive tape. DETAILED DESCRIPTION

[0061] The technical solutions of the utility model will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0062] Embodiment 1

[0063] Prepare a kind of full solid state battery, specific steps are as follows:

[0064] (1) preparation of negative pole: silicon negative pole material (silicon monoxide, SiO x1300 type, dry powder mass fraction 65%), Li6PS5Cl (dry powder mass fraction 31%), SEBS binder (dry powder mass fraction 2%), VGCF conductive agent (dry powder mass fraction 2%) are dispersed in the solvent xylene and stirred sufficiently to form a uniform and stable negative electrode material layer slurry, which is coated on both sides of the copper foil with a coating amount of 4.25 mg / cm 2 , and after drying and rolling, a negative electrode with a thickness of 77 μm is obtained; after cutting, the size of the negative electrode is 100 x 100 mm 2 ;

[0065] (2) Preparation of solid electrolyte layer: oxide solid electrolyte (LATP) and polytetrafluoroethylene are prepared by a conventional solvent-free dry process. In the solid electrolyte layer, the content of oxide solid electrolyte is 98.5%, and the content of polytetrafluoroethylene is 1.5%; the thickness is 50 μm, and the size of the solid electrolyte layer after cutting is 100 x 100 mm 2 ;

[0066] (3) Preparation of composite positive electrode: SEBS binder (dry powder mass fraction 2%) is completely dissolved in solvent xylene, and 811 ternary material (dry powder mass fraction 80%), VGCF (dry powder mass fraction 2%) and Li6PS5Cl (dry powder mass fraction 16%) are added and stirred uniformly to form a stable positive electrode material slurry; an aluminum foil with a size of 120 x 120 mm 2 is provided, and the positive electrode material slurry is coated on both sides of the aluminum foil with a coating size of 100 x 98 mm 2 (i.e. 100 mm long and 98 mm wide), with an area density of 22 mg / cm 2 , and after coating, drying and rolling, the thickness is 150 μm, forming a positive electrode material area, and SBS slurry (SBS powder and ceramic dispersed in xylene solvent, mass ratio 9:1, slurry solid content 50%) is coated on both sides of the positive electrode material area (i.e. both sides of 98 mm) of the tab and its opposite side, with a coating thickness of 160 μm and a width of 2 mm respectively, dried and cut into a positive electrode sheet with a size of 100 x 102 mm 2 ; an insulation tape made of PI material with a thickness of 10 μm, a width of 5 mm and a length of 98 mm is pasted on the upper and lower surfaces of the two sides of the positive electrode sheet which are not coated with SBS slurry to cover the edges of the positive electrode sheet completely.

[0067] (4) The full solid-state battery is prepared by stacking the negative electrode sheet, solid electrolyte layer, composite positive electrode sheet, solid electrolyte layer and negative electrode sheet in order, welding the tabs and vacuum packaging; the battery has a specification of 10 layers of positive electrode and 11 layers of negative electrode, and a capacity of 6 Ah. The battery is subjected to isostatic pressing at 150°C for 15 minutes.

[0068] Example 2

[0069] A full solid-state battery is prepared, and the specific steps are as follows:

[0070] (1) Preparation of the negative electrode: lithium metal is compounded on both sides of the copper foil to form a copper-lithium composite tape, the copper foil is 10 pm thick, and the lithium layer on both sides is 15 pm thick. After cutting, the size of the negative electrode is 100x100 mm 2 ;

[0071] (2) Preparation of the solid electrolyte layer: a sulfide solid electrolyte (Li6PS5Cl) and polytetrafluoroethylene are prepared by a conventional solvent-free dry process. In the solid electrolyte layer, the content of the solid electrolyte is 99.5%, and the content of polytetrafluoroethylene is 0.5%; the thickness is 80 pm, and the size of the solid electrolyte layer after cutting is 100x100 mm 2 ;

[0072] (3) Preparation of the composite positive electrode: SEBS binder (dry powder mass fraction 2%) is completely dissolved in solvent dimethylbenzene, lithium-rich positive electrode material (dry powder mass fraction 80%), VGCF (dry powder mass fraction 2%), and Li6PS5Cl (dry powder mass fraction 16%) are added and stirred uniformly to form a stable positive electrode material slurry; an aluminum foil with a size of 120x120 mm is provided 2 , the positive electrode material slurry is coated on both sides of the aluminum foil, the coating size is 104x98 mm 2 , the coating density is 19.5 mg / cm 2 , the thickness is 100 pm, and a positive electrode material area is formed. The tab and the positive electrode material area on the opposite side of the tab are respectively coated with SEBS slurry (SEBS powder and ceramic are dispersed in dimethylbenzene solvent, the mass ratio of the two is 4:1, and the solid content of the slurry is 40%), the coating thickness is 110 pm, and the width is 2 mm respectively, dried, and cut into a positive electrode sheet with a size of 104x102 mm 2 . An insulation tape made of PI material with a thickness of 10 pm, a width of 5 mm, and a length of 102 mm is pasted on the upper and lower surfaces of the positive electrode sheet on both sides not coated with SEBS slurry to completely cover the edges of the positive electrode sheet.

[0073] (4) The negative electrode sheet, the solid electrolyte layer, the composite positive electrode sheet, the solid electrolyte layer, and the negative electrode sheet are stacked in order, the tabs are welded, and a full solid-state battery is prepared after vacuum packaging. The battery capacity is 6 Ah. The battery is subjected to hot pressing treatment at 80°C for 10 minutes.

[0074] Example 3

[0075] A full solid-state battery is prepared, and the specific steps are as follows:

[0076] (1) Preparation of negative electrode: tin nanomaterial (65% by mass of dry powder), Li6PS5Cl (31% by mass of dry powder), SEBS binder (2% by mass of dry powder), and VGCF conductive agent (2% by mass of dry powder) are dispersed in xylene and stirred thoroughly to form a uniform and stable negative electrode material layer slurry, which is coated on both sides of a copper foil with a coating amount of 6.1 mg / cm 2 . After drying and rolling, a negative electrode with a thickness of 108 μm is obtained. The size of the negative electrode after cutting is 100 × 100 mm 2 .

[0077] (2) Preparation of solid electrolyte layer: a chloride solid electrolyte (Li3InCl6) and polytetrafluoroethylene (molecular weight 5 million, Kellogg) are prepared by a conventional solvent-free dry process. In the solid electrolyte layer, the solid electrolyte content is 96.5%, and the polytetrafluoroethylene content is 3.5%. The thickness is 10 μm, and the size of the solid electrolyte layer after cutting is 100 × 100 mm 2 .

[0078] (3) Preparation of composite positive electrode: SEBS binder (2% by mass of dry powder) is completely dissolved in solvent xylene, and lithium iron phosphate positive electrode material (80% by mass of dry powder), VGCF (2% by mass of dry powder), and Li6PS5Cl (16% by mass of dry powder) are added and stirred thoroughly to form a stable positive electrode material slurry. An aluminum foil with a size of 120 × 120 mm 2 is provided, and the positive electrode material slurry is coated on both sides of the aluminum foil with a coating size of 101 × 98 mm 2 , a coating density of 28 mg / cm 2 , and a thickness of 230 μm to form a positive electrode material area. EPDM slurry (EPDM powder and ceramic are dispersed in xylene solvent with a mass ratio of 3:1, and the solid content of the slurry is 40%) is coated on the tabs and the periphery of the positive electrode material area on the opposite side, respectively, with a coating thickness of 210 μm and a width of 3 mm. After drying, the positive electrode sheet is cut into a size of 101 × 104 mm 2 . An insulating adhesive tape made of PET material with a thickness of 5 μm, a width of 2 mm, and a length of 103 mm is attached to the upper and lower surfaces of the positive electrode sheet on both sides that are not coated with EPDM slurry to cover the edges of the positive electrode sheet completely.

[0079] (4) The negative electrode sheet, solid electrolyte layer, composite positive electrode sheet, solid electrolyte layer, and negative electrode sheet are stacked in order, the tabs are welded, and the full solid-state battery is prepared after vacuum packaging. The battery has a specification of 10 layers of positive electrode and 11 layers of negative electrode, and a capacity of 6 Ah. The battery is subjected to isostatic pressing at 60°C for 20 minutes.

[0080] Example 4

[0081] A full solid-state battery is prepared according to the following specific steps:

[0082] (1) Preparation of negative electrode: Artificial hard carbon negative electrode material (dry powder mass fraction 70%), Li6PS5Cl (dry powder mass fraction 26%), SEBS binder (dry powder mass fraction 2%), VGCF conductive agent (dry powder mass fraction 2%) are dispersed in xylene and stirred thoroughly to form a uniform and stable negative electrode material layer slurry, which is coated on both sides of a copper foil with a coating amount of 13.2 mg / cm 2 , and after drying, a negative electrode with a thickness of 226 μm is obtained; after cutting, the size of the negative electrode is 100 x 100 mm 2 ;

[0083] (2) Preparation of solid electrolyte layer: prepared by a wet process from a polymer electrolyte (PEO and LiTFSI mixture with a mass ratio of 4:1) and polyvinylidene fluoride (PVDF). In the solid electrolyte layer, the content of the polymer solid electrolyte is 98.5%, and the content of polytetrafluoroethylene is 1.5%; the thickness is 20 μm, and after cutting, the size of the solid electrolyte layer is 100 x 100 mm 2 ;

[0084] (3) Preparation of composite positive electrode: SEBS binder (dry powder mass fraction 2%) is completely dissolved in solvent xylene, and lithium manganese iron phosphate positive electrode material (dry powder mass fraction 80%), VGCF (dry powder mass fraction 2%), and Li6PS5Cl (dry powder mass fraction 16%) are added and stirred thoroughly to form a stable positive electrode material slurry; an aluminum foil with a size of 120 x 120 mm 2 is provided, and the positive electrode material slurry is coated on both sides of the aluminum foil with a coating size of 102 x 98 mm 2 , a coating density of 27 mg / cm 2 , and a thickness of 170 μm to form a positive electrode material area; chlorobutyl rubber CR slurry (CR powder and ceramic dispersed in xylene solvent with a mass ratio of 8:1, and the solid content of the slurry is 40%) is coated on the tabs and the peripheral positive electrode material area on the opposite side, respectively, with a coating thickness of 180 μm and a width of 4 mm, dried, and cut into a positive electrode sheet with a size of 102 x 106 mm 2 ; an insulating tape made of PET material with a thickness of 5 μm, a width of 3 mm, and a length of 102 mm is attached to the upper and lower surfaces of the positive electrode sheet on both sides where the CR slurry is not coated to cover the edges of the positive electrode sheet completely.

[0085] (4) The negative electrode sheet, solid electrolyte layer, composite positive electrode sheet, solid electrolyte layer, and negative electrode sheet are stacked in the order of negative electrode sheet, solid electrolyte layer, composite positive electrode sheet, solid electrolyte layer, and negative electrode sheet, the tabs are welded, and the full solid-state battery is prepared after vacuum packaging. The battery has a specification of 30 layers of positive electrode and 31 layers of negative electrode, and a capacity of 6 Ah. The battery is subjected to heat pressing treatment at 70°C for 15 minutes.

[0086] Example 5

[0087] A full solid-state battery is prepared, and the specific steps are as follows:

[0088] (1) Preparation of negative electrode: silver-carbon negative electrode material (silver particle diameter 50 nm, carbon is SP, mass ratio of the two is 1:3, dry powder mass fraction 65%), Li6PS5Cl (dry powder mass fraction 31%), SEBS binder (dry powder mass fraction 2%), VGCF conductive agent (dry powder mass fraction 2%) are dispersed in solvent xylene and fully stirred to form a uniform and stable negative electrode material layer slurry, which is coated on both sides of the copper foil, dried and rolled to obtain a negative electrode with a thickness of 30 μm; after cutting, the size of the negative electrode is 100×100 mm 2 ;

[0089] (2) Preparation of solid electrolyte layer: sulfide electrolyte (Li6PS5Cl) and polytetrafluoroethylene are prepared by a conventional solvent-free dry process. In the solid electrolyte layer, the content of solid electrolyte is 97%, and the content of polytetrafluoroethylene is 3.0%; the thickness is 15 μm, and the size of the solid electrolyte layer after cutting is 100×100 mm 2 ;

[0090] (3) Preparation of composite positive electrode: SBS binder (dry powder mass fraction 2%) is completely dissolved in solvent xylene, and lithium cobaltate positive electrode material (dry powder mass fraction 80%), VGCF (dry powder mass fraction 2%) and Li6PS5Cl (dry powder mass fraction 16%) are fully stirred to form a stable positive electrode material slurry; provide an aluminum foil with a size of 120×120 mm 2 , coat the positive electrode material slurry on both sides of the aluminum foil, the coating size is 100×98 mm 2 , the coating density is 24 mg / cm 2 , the thickness is 160 μm, and a positive electrode material area is formed. The tab and the peripheral positive electrode material area on the opposite side are respectively coated with room temperature vulcanized silicone rubber slurry (room temperature vulcanized silicone rubber and ceramic are dispersed in toluene solvent, the mass ratio of the two is 4:1, and the solid content of the slurry is 40%), the coating thickness is 180 μm, and the width is 4 mm respectively, dried, and cut into a positive electrode sheet with a size of 100×106 mm 2 ; an insulating adhesive tape made of PET material with a thickness of 5 μm, a width of 2 mm, and a length of 102 mm is respectively pasted on the upper and lower surfaces of the positive electrode sheet on both sides which are not coated with the vulcanized silicone rubber slurry to completely cover the edges of the positive electrode sheet.

[0091] (4) Stack the negative electrode sheet, solid electrolyte layer, composite positive electrode sheet, solid electrolyte layer, and negative electrode sheet in the order of negative electrode sheet, solid electrolyte layer, composite positive electrode sheet, solid electrolyte layer, and negative electrode sheet, weld the tabs, and prepare a full solid-state battery after vacuum packaging. The battery capacity is 6 Ah. The battery is subjected to isostatic pressing at 90°C for 25 minutes.

[0092] Comparative Example 1

[0093] The difference from Example 1 is that the positive electrode is not coated with the insulating material region, but only coated with the positive electrode material slurry cut into a positive electrode sheet of 100 x 102 mm 2 , and no adhesive tape is attached.

[0094] Comparative Example 2

[0095] The difference from Example 2 is that the thickness of the insulating material region is 150 μm, the thickness of the positive electrode material region is 80 μm, and the relationship L-50 μm≤M≤L+30 μm is not satisfied.

[0096] Comparative Example 3

[0097] The difference from Example 3 is that no adhesive tape is attached.

[0098] Comparative Example 4

[0099] The difference from Example 4 is that the positive electrode is not coated with the insulating material region, but only coated with the positive electrode material slurry cut into a positive electrode sheet of 102 x 106 mm 2 (i.e., only adhesive tape is attached).

[0100] Comparative Example 5

[0101] The difference from Example 5 is that the length and width of the outer edge of the insulating material region formed after coating the vulcanized silicone rubber and the insulating adhesive tape are both less than 1 mm from the negative electrode layer.

[0102] Test Example:

[0103] The full solid-state batteries prepared in the examples and comparative examples are compared in terms of performance, including the tests of short circuit rate, yield rate, cycle performance, and the like:

[0104] The above soft package batteries are subjected to rate performance and cycle performance tests on a blue electric electrochemical tester. The first charging is performed at 0.1 C, the discharge cut-off voltage is 2.5 V, the charging cut-off voltage is 4.3 V, after the first charging, 10 min of standing is performed, and then 2 times of charging and discharging tests are respectively performed at current densities of 0.2 C, 1 C, and 5 C; the cycle performance of the battery can be obtained by performing 100 times of constant current charging and discharging on the battery at 0.5 C. The above test temperature is room temperature, and the voltage range is 2.8-4.3 V. 100 batteries are tested, and the short circuit rate is compared. The experimental results are shown in Table 1.

[0105] Table 1

[0106]

[0107] The experimental results show that the all-solid-state batteries of Examples 1-5 have significant advantages in short circuit rate, yield rate and cycle performance, effectively solve the short circuit problem, and improve the performance and reliability of the battery. Comparative Example 1 has no insulation zone and adhesive tape, and will short circuit after isostatic pressing; Comparative Example 2 has an insulation layer with a thickness that does not meet the requirements, and the short circuit rate and yield rate decrease, and the cycle performance is also affected to a certain extent; Comparative Example 3 has no adhesive tape, and the short circuit rate increases, and the yield rate and cycle performance decrease significantly; Comparative Example 4 has no insulation layer, resulting in unstable battery performance; and Comparative Example 5 has an insulation layer and an adhesive tape layer with a length and width smaller than that of the negative electrode layer, resulting in an increased short circuit rate, and decreased yield rate and cycle performance.

[0108] Through the above examples and comparative experiments, it is proved that the all-solid-state battery structure of the utility model can effectively prevent short circuit, improve the performance and reliability of the battery, and has broad application prospects.

[0109] The above examples are only used to illustrate the technical solutions of the utility model, but not limit them. Although the utility model has been described in detail with reference to the above examples, those skilled in the art should understand that the technical solutions recorded in the above examples can be modified, or some or all of the technical features can be replaced equivalently without departing from the spirit and essence defined in the claims of the utility model; and these modifications or replacements are still within the scope defined in the claims of the utility model.

Claims

1. A short-circuit-preventive all-solid-state battery characterized by comprising: The all-solid-state battery comprises a solid electrolyte layer and positive and negative electrode sheets alternately stacked with the solid electrolyte layer interposed between the positive and negative electrode sheets; the solid electrolyte layer and the negative electrode sheet are equal in size; The positive electrode sheet comprises a positive electrode current collector and coating layers on both sides of the positive electrode current collector, the coating layers comprising positive electrode material regions and insulating material regions on both sides of the positive electrode material regions, the two sides being the side where the tabs are located and the opposite side; the positive electrode sheet is equal to or greater than the solid electrolyte layer in size along the direction of the side where the tabs are located and the opposite side, and greater than the solid electrolyte layer in size along the direction perpendicular to the side where the tabs are located and the opposite side; The positive electrode sheet is pasted with insulating adhesive tape on the upper and lower surfaces of the two sides along the direction perpendicular to the side where the tabs are located and the opposite side, the insulating adhesive tape covering the edges of the positive electrode sheet in the width direction in whole or in part; after the stack is pressed, the insulating adhesive tape is pressed into the adjacent solid electrolyte layer in whole or in part.

2. The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The thickness L of the insulating material region and the thickness M of the positive electrode material region satisfy the following relationship: L-50 μm≤M≤L+30 μm, the units of L and M being μm. 3.The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The width of the insulating material region is 0.5-10 mm. 4.The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The thickness of the insulating adhesive tape is 1-20 μm. 5.The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The width of the insulating adhesive tape is 0.5-10 mm.

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