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, positive plates and negative plates, the positive plates and the negative plates are alternately stacked, the solid electrolyte layer is arranged between the positive plates and the negative plates, an insulating frame layer is further arranged between the positive plates and the negative plates, and the insulating frame layer is of a hollow quadrilateral frame structure. The inner frame is smaller than the positive plate, and the outer frame is larger than the positive plate. The lithium ion battery can prevent the structural integrity of the electrolyte layer from being damaged by the shearing effect generated by the edge of the pole piece under high voltage, so that the battery is short-circuited due to contact of the positive and negative pole pieces, the yield of the lithium ion battery is obviously improved, the short-circuit rate of the battery is reduced, and the cycle performance of the battery is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to all solid state battery technical field, concretely relates to a short circuit prevention all solid state battery. BACKGROUND

[0002] Energy shortage and environmental pollution are two major problems in the world today. Considering the energy supply and tail gas pollution problems brought by traditional cars, developing new energy vehicles has become an important demand of countries all over the world, and the comprehensive replacement of traditional fuel vehicles by new energy vehicles has been on the agenda. In order to continue to compete with traditional fuel vehicles in the market, new energy vehicles must be comparable to fuel vehicles in terms of endurance mileage and cost, which requires the energy density of battery monomer to reach 350Wh / kg or even higher. With the improvement of monomer battery energy density, its safety risk is gradually increasing, and how to improve the safety of power batteries will become the focus of the industry. Solid-state batteries using solid electrolyte can reduce or even eliminate the use of liquid electrolyte, which can theoretically effectively reduce the probability of safety accidents such as fire and explosion, and are considered to be able to solve the safety problem of new energy vehicles from the root, becoming the key development direction in the field of power batteries.

[0003] In the structure of all solid state battery, a solid electrolyte layer is arranged between the positive and negative electrode sheets. Due to the difference in size between the positive and negative electrode sheets (the size of the negative electrode sheet is larger than that of the positive electrode sheet), when the laminated assembly is subjected to isostatic pressing or flat pressing, the edge of the positive electrode sheet will generate a shearing force on the electrolyte layer, which will easily cause the edge of the positive electrode sheet to pierce the electrolyte layer and come into contact with the negative electrode sheet, causing short circuit of the battery, thereby affecting the performance and reliability of the battery. Moreover, with the increase in the number of laminated sheets, the possibility of shearing, indentation or damage of the electrolyte layer by the positive electrode sheet is higher, and the probability of short circuit between the positive and negative electrode sheets is greater. CONTENT OF THE UTILITY MODEL

[0004] To solve at least one of the problems in the prior art, the utility model provides a short circuit prevention all solid state battery, which can reduce the short circuit rate of the solid state battery and improve the cycle performance of the battery by arranging a high-strength high-modulus insulating frame.

[0005] In order to achieve the above-mentioned purpose of the utility model, the following technical scheme is adopted:

[0006] The utility model provides a short circuit prevention 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, wherein the size of the positive electrode sheet is smaller than that of the negative electrode sheet (i.e. the length of the positive electrode sheet is slightly smaller than that of the negative electrode sheet, and the width of the positive electrode sheet is slightly smaller than that of the negative electrode sheet), and the size of the solid electrolyte layer is equal to that of the negative electrode sheet (i.e. the length is equal to the length, and the width is equal to the width).

[0007] The positive plate and the negative plate are further provided with an insulating frame layer, the insulating frame layer is a hollow quadrilateral frame structure, the inner frame size is smaller than the positive plate size, and the outer frame size is larger than the positive plate size; the thickness of the insulating frame layer is 0.5-20 microns;

[0008] The insulating frame layer is embedded or partially embedded in the adjacent solid electrolyte layer after the laminated plate is pressed.

[0009] The positive plate size is smaller than the negative plate size, and the size difference causes the positive plate edge to easily pierce the electrolyte layer and contact the negative plate to cause a battery short circuit during pressing. In order to solve the problem, the utility model inserts a high-strength high-modulus insulating frame between the positive plate and the negative plate, so as to avoid damage to the electrolyte layer or short circuit caused by the positive edge after being pressed.

[0010] In some embodiments, the cross-sectional structure of the battery cell before being pressed after the laminated plate is assembled is as shown in Figure 1 from bottom to top, the negative plate 2, the solid electrolyte layer 3, the insulating frame layer 4, the positive plate 1, the insulating frame layer 4, the solid electrolyte layer 3, the negative plate 2, the solid electrolyte layer 3, the insulating frame layer 4, the positive plate 1, and so on, that is, the insulating frame layer 4 is located between the positive plate 1 and the solid electrolyte layer 3. The cross-sectional structure of the battery cell after being pressed is as shown in Figure 2 the insulating frame layer 4 is embedded or partially embedded in the adjacent solid electrolyte layer 3.

[0011] In other embodiments, the cross-sectional structure of the battery cell before being pressed after the laminated plate is assembled is as shown in Figure 3 from bottom to top, the negative plate 2, the solid electrolyte layer 3, the insulating frame layer 4, the positive plate 1, the solid electrolyte layer 3, the insulating frame layer 4, the negative plate 2, the solid electrolyte layer 3, the insulating frame layer 4, the positive plate 1, the solid electrolyte layer 3, the insulating frame layer 4, the negative plate 2, and so on, that is, the insulating frame layer 4 is alternately located between the positive plate 1 and the solid electrolyte layer 3 and between the negative plate 2 and the solid electrolyte layer 3 (that is, once located between the positive plate 1 and the solid electrolyte layer 3, and next time located between the negative plate 2 and the solid electrolyte layer 3). The cross-sectional structure of the battery cell after being pressed is as shown in Figure 4 the insulating frame layer 4 is embedded or partially embedded in the adjacent solid electrolyte layer 3.

[0012] The size of each part is shown in Figure 5As shown, the size relationship is as follows: e < a < c, f < b < d, f < h, e < g; h = n; g = m; the inner frame size of the insulation frame is smaller than the positive plate, and the outer frame size is larger than the positive plate, that is, the edge of the positive plate is within the range of the insulation frame (equivalent to the positive plate is placed on the insulation frame, and the insulation frame partially covers the positive plate), which can prevent the shear effect of the edge of the positive plate during the pressing process of the battery cell from damaging the electrolyte, thereby causing short circuit of the positive and negative plates; it can be understood that the inner frame size of the insulation frame is also smaller than the negative plate, and the outer frame size has no special requirement for the size of the negative plate, and can be slightly larger, slightly smaller or equal, and is preferably greater than or equal to the size of the negative plate.

[0013] The size relationship referred to herein of the utility model is the length compared with the length and the width compared with the width unless otherwise specified.

[0014] The thickness of the insulation frame layer of the utility model is 0.5-20 μm, within the thickness range, the insulation frame can effectively resist the shear damage effect of the edge of the positive plate during the pressing process of the battery cell, and does not affect other performances of the battery cell. If the thickness is too thin, the effect of resisting the shear damage of the positive plate is poor, the risk of short circuit is increased, and if the thickness is too thick, the multi-layer battery will cause the thickness of the battery cell around the frame to be higher than the center area without the frame, which is easy to cause the positive plate to break, and the inconsistent thickness may also cause the battery cell to be unable to be pressed during the later application process, affecting the performance of the battery cell.

[0015] Insulation frame layer (quadrilateral frame structure):

[0016] In some embodiments, the material of the insulation frame layer includes one or more of polytetrafluoroethylene and its copolymer, polyvinylidene fluoride and its copolymer, polyethylene and its copolymer, polypropylene and its copolymer, polyimide, polyetherimide, aramid, PET, PEEK. Preferably, the tensile strength of these materials is ≥20 MPa, the elastic modulus is ≥0.1 GPa, and the compressive strength is ≥10 MPa; if the strength and modulus are lower than the range, the effect of the insulation frame resisting the shear damage of the positive plate will be weakened, and the short circuit rate of the battery will be increased.

[0017] In some embodiments, the difference (i.e. 2 x width) between the outer frame size and the inner frame size of the quadrilateral frame of the insulation frame layer is 0.5-20 mm, that is, 0.5 mm < c-e < 20 mm; 0.5 mm < d-f < 20 mm.

[0018] The quadrilateral frame structure can be an integral structure or can be combined by four side frames.

[0019] Positive plate:

[0020] The positive electrode sheet includes a positive current collector and positive electrode material layers on both sides. The positive electrode material layers include the following components by mass percentage: 70-94% positive electrode active material, 1-3% conductive agent, 1-3% binder, and 4-28% sulfide electrolyte.

[0021] In some implementations, the positive current collector is aluminum foil;

[0022] In some embodiments, the positive electrode active material is at least one selected from ternary materials, lithium iron phosphate, lithium cobalt oxide, lithium manganese iron phosphate, lithium-rich manganese-based materials, and sulfur positive electrode materials (such as composites of sulfur and carbon, or composites of sulfur and organic matter).

[0023] In some embodiments, the conductive agent is at least one selected from acetylene black, Super P, Super S, 350G, carbon fiber VGCF, carbon nanotubes CNTs, Ketjen black, graphite conductive agents (such as KS-6, KS-15, SFG-6, SFG-15) and graphene.

[0024] In some embodiments, the binder is at least one selected from polyvinylidene fluoride (PVDF) and its modified forms, polytetrafluoroethylene (PTFE) and its modified forms, polyethylene oxide (PEO), polypropylene carbonate (PPC), polyvinyl carbonate (PEC), polytrimethylene carbonate (PTMC), polyvinyl alcohol (PVA), sodium carboxymethyl cellulose (CMC), polyolefins (polyethylene, polypropylene and their copolymers), hydrogenated styrene-butadiene block copolymer (SEBS), cyano rubber (NBR), modified SBR, fluorinated rubber, and polyurethane.

[0025] In some embodiments, the sulfide electrolyte is at least one selected from binary sulfide electrolytes, ternary sulfide electrolytes, and sulfide-germanium sulfide electrolytes, preferably lithium phosphorus sulfur chloride (Li6PS5Cl).

[0026] The thickness of the positive electrode can be 30–450 μm.

[0027] Negative electrode plate:

[0028] The negative electrode sheet includes a negative electrode current collector and negative electrode material layers on both sides. The negative electrode material layers include the following components by mass percentage: 60-90% negative electrode active material, 1-3% conductive agent, 1-3% binder, and 4-38% sulfide electrolyte.

[0029] In some implementations, the negative current collector is copper foil;

[0030] In some embodiments, the negative active material is at least one selected from carbon materials (such as conductive carbon black, carbon nanotubes, graphene, fullerenes, carbon nanofibers), 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).

[0031] In some embodiments, the conductive agent is at least one selected from acetylene black, Super P, Super S, Denka® 350G, carbon fiber VGCF, carbon nanotube CNTs, Ketjen black, graphite conductive agents (such as KS-6, KS-15, SFG-6, SFG-15), and graphene.

[0032] 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.

[0033] In some embodiments, the sulfide electrolyte is at least one selected from binary sulfide electrolytes, ternary sulfide electrolytes, and argyrodite-type sulfide electrolytes, and preferably lithium phosphorus sulfide chloride (Li6PS5Cl).

[0034] The thickness of the negative electrode sheet can be 20 to 400 μm.

[0035] The solid electrolyte layer includes the following components in mass percentage: solid electrolyte 95 to 99.5% and binder 0.5 to 5%.

[0036] The solid electrolyte layer includes the following components in mass percentage: solid electrolyte 95 to 99.5% and binder 0.5 to 5%.

[0037] In some embodiments, the solid electrolyte is at least one selected from sulfide electrolytes, oxide electrolytes, chloride electrolytes, polymer electrolytes; and preferably lithium phosphorus sulfide chloride (Li6PS5Cl).

[0038] 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.

[0039] The thickness of the solid electrolyte layer can be 5-200 μm.

[0040] The preparation method of the short-circuit prevention all-solid-state battery described above comprises one of the following methods:

[0041] Method one:

[0042] A solid electrolyte layer is provided; a negative electrode material slurry is coated on both sides of a negative electrode current collector, and a negative electrode sheet is obtained after drying; a positive electrode material slurry is coated on both sides of a positive electrode current collector, and a positive electrode sheet is obtained after drying; the solid electrolyte layer is cut to have the same size as the negative electrode sheet, and the positive electrode sheet is cut to have a size smaller than that of the negative electrode sheet;

[0043] An insulating frame layer with a hollow quadrilateral frame structure is provided, the inner frame size of the insulating frame layer is smaller than the size of the positive electrode sheet, and the outer frame size is larger than the size of the positive electrode sheet; the thickness of the insulating frame layer is 0.5-20 μm; the insulating frame layer is compounded on the solid electrolyte layer to obtain a compounded solid electrolyte layer;

[0044] The negative electrode sheet, the compounded solid electrolyte layer, the positive electrode sheet, the compounded solid electrolyte layer, and the negative electrode sheet are sequentially stacked in this order, the insulating frame layer is in contact with the positive electrode sheet, and an electric core (as shown in FIG. 1) is obtained; Figure 1

[0045] The electric core is subjected to a pressing treatment to obtain a pressed electric core (as shown in FIG. 2); Figure 2

[0046] Method two:

[0047] A solid electrolyte layer is provided; a negative electrode material slurry is coated on both sides of a negative electrode current collector, and a negative electrode sheet is obtained after drying; a positive electrode material slurry is coated on both sides of a positive electrode current collector, and a positive electrode sheet is obtained after drying; the solid electrolyte layer is cut to have the same size as the negative electrode sheet, and the positive electrode sheet is cut to have a size smaller than that of the negative electrode sheet;

[0048] An insulating frame layer with a hollow quadrilateral frame structure is provided, the inner frame size of the insulating frame layer is smaller than the size of the positive electrode sheet, and the outer frame size is larger than the size of the positive electrode sheet; the thickness of the insulating frame layer is 0.5-20 μm; the insulating frame layer is compounded on the solid electrolyte layer to obtain a compounded solid electrolyte layer;

[0049] The negative electrode sheet, the compounded solid electrolyte layer, the positive electrode sheet, the compounded solid electrolyte layer, and the negative electrode sheet are sequentially stacked in this order, the insulating frame layer is alternately in contact with the positive electrode sheet and the negative electrode sheet, and an electric core (as shown in FIG. 3) is obtained; Figure 3

[0050] The electric core is subjected to a pressing treatment to obtain a pressed electric core (as shown in FIG. 4). Figure 4

[0051] ​​​​The positive electrode sheet, the solid electrolyte layer and the negative electrode sheet are obtained through a conventional process; and then the positive electrode sheet, the solid electrolyte layer and the negative electrode sheet are cut.

[0052] The insulating frame and the solid electrolyte layer can be combined by electrostatic adsorption or coating adhesive.

[0053] Preferably, the pressurizing mode comprises one of isostatic pressing, flat plate pressing and roller pressing, the pressurizing temperature is 0-1000 DEG C, the pressurizing time is 0.5-30 minutes, and the pressure is 3-1000 MPa.

[0054] Beneficial effects:

[0055] The utility model discloses a solid electrolyte layer is compounded between the positive and negative electrode sheet high strength high modulus insulating frame layer, and the frame body structure part is embedded in the solid electrolyte layer after pressing or completely, and the positive electrode sheet edge is within the insulating frame range. Such design can prevent the shear action of the edge of the electrode sheet under high pressure from destroying the structural integrity of the electrolyte layer, make the positive and negative electrode sheet contact cause the battery short circuit, significantly improve the yield of lithium ion battery, reduce the short circuit rate of the battery, improve the cycle performance of the battery.

[0056] The utility model has been described in the foregoing in detail, but the above-mentioned implementation mode is only illustrative in essence, and is not desired 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

[0057] Figure 1 It is the full solid battery lamination assembly before being pressed of an embodiment of the utility model cross section structure diagram of electric core;

[0058] Figure 2 It is the full solid battery lamination assembly after being pressed of an embodiment of the utility model cross section structure diagram of electric core;

[0059] Figure 3 It is the full solid battery lamination assembly before being pressed of another embodiment of the utility model cross section structure diagram of electric core;

[0060] Figure 4 It is the full solid battery lamination assembly after being pressed of another embodiment of the utility model cross section structure diagram of electric core;

[0061] Figure 5 It is the size schematic diagram of each part of the full solid battery of the utility model.

[0062] Illustration: 1-positive electrode sheet;2-negative electrode sheet;3-solid electrolyte layer;4-insulating frame layer. DETAILED DESCRIPTION

[0063] The technical solutions of the present application will be clearly and completely described below with examples. Obviously, the described examples are some of the embodiments of the present application, but not all the embodiments. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0064] Example 1

[0065] A full solid-state battery is prepared, and the specific steps are as follows:

[0066] (1) Preparation of positive electrode sheet: SEBS binder (dry powder mass fraction 2%) is completely dissolved in solvent dimethylbenzene, 811 ternary positive electrode material (dry powder mass fraction 80%), VGCF conductive agent (dry powder mass fraction 2%) and Li6PS5Cl (dry powder mass fraction 16%) are fully stirred and uniformly mixed to form a stable positive electrode material slurry, which is coated on both sides of a 12 μm thick aluminum foil with a coating amount of 18 mg / cm 2 , and after drying, a positive electrode sheet with a thickness of 150 μm is obtained, and after cutting, the size of the positive electrode sheet is 57×77mm 2 (i.e. 57mm×77mm);

[0067] (2) Preparation of negative electrode sheet: silicic oxide negative electrode material (dry powder mass fraction 60%), Li6PS5Cl (dry powder mass fraction 36%), SEBS binder (dry powder mass fraction 2%), VGCF conductive agent (dry powder mass fraction 2%) and solvent dimethylbenzene are fully stirred to form a uniform and stable negative electrode material slurry, which is coated on both sides of a 6 μm copper foil with a coating amount of 5 mg / cm 2 , and after drying, a negative electrode sheet with a thickness of 86 μm is obtained, and after cutting, the size of the negative electrode sheet is 60×80mm 2 ;

[0068] (3) Preparation of solid electrolyte layer: 651 type sulfide solid electrolyte Li6PS5Cl and polytetrafluoroethylene are prepared by a conventional solvent-free dry process. In the solid electrolyte layer, the content of 651 type sulfide solid electrolyte is 99.5%, and the content of polytetrafluoroethylene is 0.5%; the thickness is 50 μm, and after cutting, the size of the solid electrolyte layer is 60×80mm 2 ;

[0069] (4) Provide an insulating frame layer with a hollow quadrilateral frame structure: the material is polytetrafluoroethylene, the thickness is 1 μm, the tensile strength is 30 MPa, the elastic modulus is 0.2 GPa, the compressive strength is 15 MPa, and after cutting, the size of the inner frame is 55×75mm 2 , and the size of the outer frame is 62×82mm 2 .

[0070] (5) Composite the insulating frame layer on one side of the solid electrolyte layer to obtain a composite solid electrolyte layer; stack the negative electrode sheet, the composite solid electrolyte layer, the positive electrode sheet, the composite solid electrolyte layer, and the negative electrode sheet in sequence (the geometric centers of the positive electrode sheet, the solid electrolyte layer, the negative electrode sheet, and the insulating frame are aligned), with the insulating frame layer being connected to the positive electrode sheet, to obtain a battery cell, the number of positive and negative electrode sheets of the battery cell is 10 positive and 11 negative, and the design capacity is 2 Ah.

[0071] (6) Perform isostatic pressing on the stacked battery cell at 200 ℃ for 10 minutes, and the pressure is 200 MPa.

[0072] Example 2

[0073] Prepare a full solid-state battery, and the specific steps are as follows:

[0074] (1) Prepare a positive electrode sheet: completely dissolve SEBS binder (dry powder mass fraction 2%) in solvent dimethylbenzene, add lithium iron phosphate positive electrode material (dry powder mass fraction 80%), VGCF conductive agent (dry powder mass fraction 2%), and Li6PS5Cl (dry powder mass fraction 16%), and fully stir to obtain a stable positive electrode material slurry, coat the slurry on both sides of a 12 μm aluminum foil, and the coating amount is 22 mg / cm 2 . After drying, roll to obtain a positive electrode sheet with a thickness of 212 μm, and the size of the cut positive electrode sheet is 57×77 mm 2 .

[0075] (2) Prepare a negative electrode sheet: composite lithium metal on a copper foil to form a copper-lithium composite strip, the copper foil is 6 μm thick, and the lithium metal layer on both sides is 20 μm thick, and the size of the cut negative electrode sheet is 60×80 mm 2 .

[0076] (3) Prepare a solid electrolyte layer: dissolve LLZO oxide solid electrolyte, PEO, and lithium salt in NMP, and in the solid electrolyte layer, the content of the oxide solid electrolyte is 40%, the content of PEO is 40%, and the content of lithium salt is 20%, the thickness is 50 μm, and the size of the cut solid electrolyte layer is 60×80 mm 2 .

[0077] (4) Provide an insulating frame layer with a hollow quadrilateral frame structure: the material is polyvinylidene fluoride, the thickness is 1 μm, the tensile strength is 70 MPa, the elastic modulus is 0.2 GPa, the compressive strength is 15 MPa, the size of the cut inner frame is 42×62 mm 2 , and the size of the cut outer frame is 62×82 mm 2 (the frame width is 10 mm).

[0078] (5) The insulating frame is coated with a solvent-free epoxy adhesive to adhere to the single-sided electrolyte layer to form a composite solid electrolyte layer; the negative electrode sheet, the composite solid electrolyte layer, the positive electrode sheet, the composite solid electrolyte layer, and the negative electrode sheet are stacked in order (the geometric centers of the positive electrode sheet, the solid electrolyte layer, the negative electrode sheet, and the insulating frame are aligned), the insulating frame layer is connected to the positive electrode sheet, and the battery cell is obtained, the number of positive and negative electrode sheets of the battery cell is 10 positive and 11 negative, and the design capacity is 1.7 Ah.

[0079] (6) The stacked battery cell is subjected to isostatic pressing at 30°C for 0.5 minutes at a pressure of 3 MPa.

[0080] Example 3

[0081] A full solid-state battery is prepared, and the specific steps are as follows:

[0082] (1) Preparation of a positive electrode sheet: SEBS binder (dry powder mass fraction 2%) is completely dissolved in solvent dimethylbenzene, lithium cobaltate positive electrode material (dry powder mass fraction 80%), VGCF conductive agent (dry powder mass fraction 2%), and Li6PS5Cl (dry powder mass fraction 16%) are added and fully stirred to form a stable positive electrode material slurry, which is coated on both sides of a 12 μm aluminum foil at a coating amount of 20 mg / cm 2 , and after drying, a positive electrode sheet with a thickness of 155 μm is obtained, and after cutting, the positive electrode sheet size is 57×77 mm 2 ;

[0083] (2) Preparation of a negative electrode sheet: silicon monoxide negative electrode material (dry powder mass fraction 60%), Li6PS5Cl (dry powder mass fraction 36%), SEBS binder (dry powder mass fraction 2%), VGCF conductive agent (dry powder mass fraction 2%), and solvent dimethylbenzene are fully stirred to form a uniform and stable negative electrode material slurry, which is coated on both sides of a 6 μm copper foil at a coating amount of 5 mg / cm 2 , and after drying, a negative electrode sheet with a thickness of 86 μm is obtained, and after cutting, the negative electrode sheet size is 60×80 mm 2 ;

[0084] (3) Preparation of a solid electrolyte layer: a 651-type sulfide solid electrolyte and polytetrafluoroethylene are prepared by a conventional solvent-free dry process. In the solid electrolyte layer, the content of the 651-type sulfide solid electrolyte is 99.0%, and the content of polytetrafluoroethylene is 1%; the thickness is 50 μm, and after cutting, the solid electrolyte layer size is 60×80 mm 2 ;

[0085] (4) An insulating frame layer with a hollow quadrilateral frame structure is provided: the material is polyethylene-styrene copolymer, the thickness is 20 μm, the tensile strength is 130 MPa, the elastic modulus is 0.5 GPa, the compressive strength is 10 MPa, and after cutting, the inner frame size is 56.8×76.8 mm2 , outer frame size: 61 x 80 mm 2 .

[0086] (5) The insulating frame layer is compounded on one side of the solid electrolyte layer to obtain a composite solid electrolyte layer; the negative electrode sheet, the composite solid electrolyte layer, the positive electrode sheet, the composite solid electrolyte layer, and the negative electrode sheet are stacked in turn (the geometric centers of the positive electrode sheet, the solid electrolyte layer, the negative electrode sheet, and the insulating frame are aligned), the insulating frame layer is connected with the positive electrode sheet, and a battery cell is obtained, the number of layers of the positive and negative electrode sheets of the battery cell is 10 positive and 11 negative, and the design capacity is 2 Ah.

[0087] (6) The stacked battery cell is subjected to isostatic pressing at 80°C for 10 minutes, and the pressure is 600 MPa.

[0088] Example 4

[0089] A full solid-state battery is prepared, and the specific steps are as follows:

[0090] (1) Preparation of a positive electrode sheet: SEBS binder (dry powder mass fraction 2%) is completely dissolved in solvent dimethylbenzene, lithium-rich manganese-based solid solution LMO positive electrode material (dry powder mass fraction 70%), VGCF conductive agent (dry powder mass fraction 2%), and Li6PS5Cl (dry powder mass fraction 26%) are fully stirred and uniformly mixed to form a stable positive electrode material slurry, which is coated on both sides of a 12 μm thick aluminum foil, and the coating amount is 17.5 mg / cm 2 , and after drying, the positive electrode sheet with a thickness of 164 μm is obtained, and the size of the positive electrode sheet after cutting is 57 x 77 mm 2 ;

[0091] (2) Preparation of a negative electrode sheet: silver-carbon lithium-free negative electrode material (dry powder mass fraction 80%, carbon material in silver-carbon is carbon nanotube, silver is nano silver particle, and the mass ratio of silver to carbon is 1:9), Li6PS5Cl (dry powder mass fraction 16%), SEBS binder (dry powder mass fraction 2%), VGCF conductive agent (dry powder mass fraction 2%), and solvent dimethylbenzene are fully stirred to form a uniform and stable negative electrode material slurry, which is coated on both sides of a 6 μm copper foil, and the coating amount is 5 mg / cm 2 , and after drying, the negative electrode sheet with a thickness of 75 μm is obtained, and the size of the negative electrode sheet after cutting is 60 x 80 mm 2 ;

[0092] (3) Preparation of a solid electrolyte layer: a 651 type sulfide solid electrolyte and polytetrafluoroethylene are prepared by a conventional solvent-free dry process. In the solid electrolyte layer, the content of the 651 type sulfide solid electrolyte is 98%, and the content of polytetrafluoroethylene is 2%; the thickness is 30 μm, and the size of the solid electrolyte layer after cutting is 60 x 80 mm 2 ;

[0093] (4) Provide an insulating frame layer of hollow quadrilateral frame structure: material polyimide, thickness 4 μm, tensile strength 160 MPa, elastic modulus 1.5 GPa, compressive strength 30 MPa, after cutting the inner frame size: 55 x 75 mm 2 , the outer frame size: 61 x 80 mm 2 .

[0094] (5) Compound the insulating frame layer on one side of the solid electrolyte layer to obtain a composite solid electrolyte layer; stack in the order of negative electrode sheet, composite solid electrolyte layer, positive electrode sheet, composite solid electrolyte layer, negative electrode sheet (the geometric centers of the positive electrode sheet, solid electrolyte layer, negative electrode sheet, and insulating frame are aligned, and the insulating frame contacts the positive electrode), and the insulating frame layer contacts the positive electrode sheet to obtain an electric core with 10 positive and 11 negative electrode sheet layers and a design capacity of 2 Ah.

[0095] (6) Perform isostatic pressing treatment on the stacked electric core at 80°C for 10 minutes at a pressure of 600 MPa.

[0096] Example 5

[0097] Prepare a full solid-state battery, and the specific steps are as follows:

[0098] (1) Prepare a positive electrode sheet: completely dissolve SEBS binder (dry powder mass fraction 2%) in solvent dimethylbenzene, add lithium manganese iron phosphate positive electrode material (dry powder mass fraction 70%), VGCF conductive agent (dry powder mass fraction 2%), and Li6PS5Cl (dry powder mass fraction 26%) to form a stable positive electrode material slurry, coat on both sides of a 12 μm thick aluminum foil, coating amount 23 mg / cm 2 , after drying, roll to obtain a positive electrode sheet with a thickness of 231 μm, and after cutting, the positive electrode sheet size is 57 x 77 mm 2 ;

[0099] (2) Prepare a negative electrode sheet: fully stir nano-silicon negative electrode material (dry powder mass fraction 65%), Li6PS5Cl (dry powder mass fraction 30%), SEBS binder (dry powder mass fraction 3%), VGCF conductive agent (dry powder mass fraction 2%), and solvent dimethylbenzene to form a uniform and stable negative electrode material slurry, coat on both sides of a 6 μm copper foil, coating amount 1.9 mg / cm 2 , after drying, obtain a negative electrode sheet with a thickness of 40 μm, and after cutting, the negative electrode sheet size is 60 x 80 mm 2 ;

[0100] (3) Preparation of solid electrolyte layer: prepared by a conventional solvent-free dry process from 651 sulfide solid electrolyte and polytetrafluoroethylene. In the solid electrolyte layer, the content of 651 sulfide solid electrolyte is 96%, and the content of polytetrafluoroethylene is 4%; the thickness is 40 μm, and the size of the solid electrolyte layer after cutting is 60 x 80 mm 2 ;

[0101] (4) Provide an insulating frame layer with a hollow quadrilateral frame structure: the material is aramid fiber, the thickness is 10 μm, the tensile strength is 100 MPa, the elastic modulus is 0.5 GPa, the compressive strength is 25 MPa, and the size of the inner frame after cutting is 55 x 75 mm 2 , the size of the outer frame is 61 x 80 mm 2 .

[0102] (5) Composite the insulating frame layer on one side of the solid electrolyte layer to obtain a composite solid electrolyte layer; stack in the order of negative electrode sheet, composite solid electrolyte layer, positive electrode sheet, composite solid electrolyte layer, negative electrode sheet (the geometric centers of the positive electrode sheet, solid electrolyte layer, negative electrode sheet, and insulating frame are aligned, and the insulating frame is in contact with the positive electrode), and the insulating frame layer is in contact with the positive electrode sheet to obtain a battery cell, the number of positive and negative electrode sheets of the battery cell is 10 positive and 11 negative, and the design capacity is 2 Ah.

[0103] (6) Perform isostatic pressing on the stacked battery cell at 150°C for 10 minutes at a pressure of 1000 MPa.

[0104] Example 6

[0105] Prepare a full solid-state battery, the specific steps are as follows:

[0106] (1) Preparation of positive electrode sheet: completely dissolve SEBS binder (dry powder mass fraction 2%) in solvent xylene, add 9 series ternary positive electrode material (NCM90) (dry powder mass fraction 80%), VGCF conductive agent (dry powder mass fraction 2%) and Li6PS5Cl (dry powder mass fraction 16%), stir well to form a stable positive electrode material slurry, coat on both sides of the 12 μm aluminum foil, coating amount 18 mg / cm 2 , after drying, roll to obtain a positive electrode sheet with a thickness of 150 μm, and the size of the positive electrode sheet after cutting is 57 x 77 mm 2 ;

[0107] (2) Preparation of negative electrode sheet: fully stir silicon monoxide negative electrode sheet material (dry powder mass fraction 60%), Li6PS5Cl (dry powder mass fraction 36%), SEBS binder (dry powder mass fraction 2%), VGCF conductive agent (dry powder mass fraction 2%) and solvent xylene to form a uniform and stable negative electrode material slurry, coat on both sides of the 6 μm copper foil, coating amount 5 mg / cm 2After drying, the negative electrode sheet with a thickness of 86 μm is obtained, and the size of the negative electrode sheet after cutting is 60 x 80 mm 2 ;

[0108] (3) Preparation of solid electrolyte layer: electrolyte film is obtained by wet coating of 651 type sulfide solid electrolyte and SEBS. In the solid electrolyte layer, the content of 651 type sulfide solid electrolyte is 98%, and the content of SEBS is 2%; the thickness is 50 μm, and the size of the solid electrolyte layer after cutting is 60 x 80 mm 2 ;

[0109] (4) Provide an insulating frame layer with a hollow quadrilateral frame structure: the material is polyimide, the thickness is 6 μm, the tensile strength is 200 MPa, the elastic modulus is 1.2 GPa, the compressive strength is 35 MPa, and the size of the inner frame after cutting is 55 x 75 mm 2 , and the size of the outer frame is 62 x 82 mm 2 .

[0110] (5) Compound the insulating frame layer on one side of the solid electrolyte layer to obtain a composite solid electrolyte layer; stack the negative electrode sheet, the composite solid electrolyte layer, the positive electrode sheet, the composite solid electrolyte layer, and the negative electrode sheet in order (the geometric centers of the positive electrode sheet, the solid electrolyte layer, the negative electrode sheet, and the insulating frame are aligned, and the insulating frame is in contact with the positive electrode), the insulating frame layer is in contact with the positive electrode sheet, and the battery cell is obtained, the number of positive and negative electrode sheets of the battery cell is 10 positive and 11 negative, and the design capacity is 2 Ah.

[0111] (6) The stacked battery cell is subjected to isostatic pressing at 50°C for 10 minutes, and the pressure is 400 MPa.

[0112] Comparative Example 1

[0113] The difference from Example 1 is that the insulating frame layer is not used.

[0114] Comparative Example 2

[0115] The difference from Example 3 is that the thickness of the insulating frame layer is 25 μm, which exceeds the range of 0.5-20 μm.

[0116] Comparative Example 3

[0117] The difference from Example 3 is that the size of the insulating frame after cutting is 56.9 x 76.9 mm 2 , and the size of the outer frame is 57 x 77 mm 2 .

[0118] Comparative Example 4

[0119] The difference from Example 3 is that the size of the insulating frame after cutting is 57 x 77 mm 2 , and the size of the outer frame is 59 x 79 mm2 .

[0120] Comparative Example 5

[0121] The difference from Example 3 is that the size of the inner frame after trimming: 56.9x76.9mm 2 , the size of the outer frame: 58x77mm 2 .

[0122] Test:

[0123] The above soft package battery was tested for rate performance and cycle performance on a blue electric chemical tester. The first charge was performed at 0.1C, the discharge cutoff voltage was 2.5V, the charge cutoff voltage was 4.3V, after the first charge, 10min was rested, then 2 times of charge-discharge test was performed at current density of 0.2C, 1C and 5C respectively; the cycle performance of the battery was obtained by 100 times of constant current charge-discharge of the battery at 0.5C. The above test temperature was room temperature, and the voltage range was 2.8-4.3V. 100 batteries were tested, and the short circuit rate was compared, and the experimental results are shown in Table 1.

[0124] Table 1

[0125]

[0126] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing 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 present application.

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 positive electrode sheet having a size smaller than that of the negative electrode sheet, and the solid electrolyte layer having a size equal to that of the negative electrode sheet. An insulating frame layer is further provided between the positive and negative electrode sheets, the insulating frame layer being a hollow quadrangular frame structure, the inner frame of the quadrangular frame structure having a size smaller than that of the positive electrode sheet, and the outer frame having a size larger than that of the positive electrode sheet. After the stacking and pressing, the insulating frame layer is embedded or partially embedded in the adjacent solid electrolyte layer.

2. The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The insulating frame layer is entirely located between the positive electrode sheet and the solid electrolyte layer. 3.The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The insulating frame layer is alternately located between the positive electrode sheet and the solid electrolyte layer and between the negative electrode sheet and the solid electrolyte layer. 4.The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The thickness of the insulating frame layer is 0.5-20 μm. 5.The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The difference between the outer frame size and the inner frame size of the quadrangular frame structure of the insulating frame layer is 0.5-20 mm. 6.The short-circuit-preventive all-solid-state battery according to claim 1, characterized by, The outer frame size of the quadrangular frame structure of the insulating frame layer is equal to or larger than the size of the negative electrode sheet.

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