All-solid-state battery cell and soft package all-solid-state lithium metal battery

Abstract

The invention relates to an all-solid-state battery cell and a soft package all-solid-state lithium metal battery. The all-solid-state battery cell comprises a positive current collector, a positive plate, a solid electrolyte, a lithium metal negative plate and a negative current collector which are stacked in sequence; the positive plate comprises a first sub-positive plate and a second sub-positive plate which are stacked in the direction away from the positive current collector, and the projection of the first sub-positive plate on the solid electrolyte covers the projection of the second sub-positive plate on the solid electrolyte; the projection area of the first sub-positive plate on the solid electrolyte is larger than that of the second sub-positive plate on the solid electrolyte; the all-solid-state battery cell further comprises an insulation pad, the insulation pad is arranged on the periphery of the second positive sub-plate in a sleeving mode, and the two surfaces of the insulation pad abut against the first positive sub-plate and the solid electrolyte respectively. According to the all-solid-state battery cell, the insulation pad is arranged on one side of the positive electrode at the interface of the positive plate and the solid electrolyte, so that edge lithium precipitation is reduced, and the problem of lithium precipitation in the charging and discharging process of the battery is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of all-solid-state batteries, and particularly to an all-solid-state battery cell and a flexible all-solid-state lithium metal battery. Background Art

[0002] With the wide application of lithium-ion batteries in fields such as portable mobile devices, energy storage devices, and electric vehicles, the requirements for their safety and energy density are getting higher and higher. Lithium metal has a high theoretical specific capacity (3860 mAh g-1) and a low electrode potential (-3.04 V, compared with the standard hydrogen electrode), so lithium metal batteries are a promising alternative to lithium-ion batteries.

[0003] In traditional all-solid-state lithium metal batteries, due to the poor contact of the solid-solid interface, uneven deposition of lithium occurs during battery charge and discharge. The deposition of lithium ions inside the battery will form dendrites, causing internal short circuits or capacity loss of the battery; the deposition of lithium at the edge of the battery will lead to capacity loss of the battery and deterioration of the interface contact. Summary of the Invention

[0004] Based on this, in order to solve the problem of lithium deposition during battery charge and discharge, it is necessary to provide an all-solid-state battery cell and a flexible all-solid-state lithium metal battery.

[0005] An all-solid-state battery cell, the all-solid-state battery cell includes a positive current collector, a positive electrode sheet, a solid electrolyte, a lithium metal negative electrode sheet, and a negative current collector that are sequentially stacked;

[0006] Wherein, the positive electrode sheet includes a first sub-positive electrode sheet and a second sub-positive electrode sheet stacked in a direction away from the positive current collector, the projection of the first sub-positive electrode sheet on the solid electrolyte covers the projection of the second sub-positive electrode sheet on the solid electrolyte, and the projection area of the first sub-positive electrode sheet on the solid electrolyte is larger than the projection area of the second sub-positive electrode sheet on the solid electrolyte;

[0007] The all-solid-state battery cell further includes an insulating pad, the insulating pad is sleeved on the periphery of the second sub-positive electrode sheet, and two surfaces of the insulating pad are respectively in contact with the first sub-positive electrode sheet and the solid electrolyte.

[0008] The above all-solid-state battery cell includes an insulating pad. On the one hand, it reduces the contact area between the positive electrode sheet and the solid electrolyte, and the area allowing current passage in the overhang area on the negative electrode side is reduced; on the other hand, it also improves the stress distribution after pressurization at the negative electrode interface and changes the current density distribution in the negative electrode area. The all-solid-state battery cell of the present invention reduces edge lithium deposition from the above two aspects.

[0009] In a feasible implementation manner, the first sub-positive electrode sheet and the second sub-positive electrode sheet are integrally formed.

[0010] In a feasible implementation, the outer diameter of the insulating pad is the same as the outer perimeter of the first sub-positive electrode plate, and the inner diameter of the insulating pad is the same as the outer perimeter of the second sub-positive electrode plate.

[0011] In a feasible implementation, the thickness of the insulating pad is the same as the thickness of the second sub-positive electrode plate.

[0012] In a feasible implementation, the thickness of the insulating pad is 20 μm to 30 μm.

[0013] In a feasible implementation, half of the difference between the outer and inner diameters of the insulating pad is 1.5 mm to 2.5 mm.

[0014] In a feasible implementation, the material of the insulating pad includes one or a combination of rubber, polyethylene, and polytetrafluoroethylene.

[0015] In a feasible implementation, the ratio of the thickness of the second sub-positive electrode plate to the thickness of the first sub-positive electrode plate is 0.182 to 0.3.

[0016] In a feasible implementation, the ratio of the projected area of the second sub-positive electrode plate on the solid electrolyte to the projected area of the first sub-positive electrode plate on the solid electrolyte is 0.766 to 0.856.

[0017] A soft-pack all-solid-state lithium metal battery includes the all-solid-state battery cell described in any one of the above.

[0018] The all-solid-state lithium metal battery of the technical solution of the present invention includes the above all-solid-state battery cell, and the all-solid-state battery cell includes an insulating pad. On the one hand, it reduces the contact area between the positive electrode plate and the solid electrolyte, and the area of the negative electrode side overhang region that allows current to pass through is reduced; on the other hand, it also improves the stress distribution after pressurization at the negative electrode interface and changes the current density distribution in the negative electrode region. The soft-pack all-solid-state lithium metal battery of the present invention reduces edge lithium deposition from the above two aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a three-dimensional schematic view of an all-solid-state battery cell according to an embodiment of the present invention;

[0020] Figure 2 is an exploded schematic view of an all-solid-state battery cell according to an embodiment of the present invention;

[0021] Figure 3 is a top view of an all-solid-state battery cell according to an embodiment of the present invention;

[0022] Figure 4 is a front view of an all-solid-state battery cell according to an embodiment of the present invention;

[0023] Figure 5 For along Figure 4 The sectional view taken along B - B' in Specific embodiments

[0024] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0025] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0027] The inventors of the present invention have found that due to the poor contact at the solid - solid interface in all - solid - state lithium - metal batteries, appropriate pressure is applied to the battery during the charge - discharge cycle of the all - solid - state battery to improve the incomplete contact at the solid - solid interface. However, due to the pressure application, the uneven stress on the lithium - metal negative electrode will cause excessive lithium deposition in the overhang region.

[0028] To solve the above problems, through creative research, the inventors of the present invention propose an all - solid - state battery cell. By providing an insulating pad on the positive - electrode side at the interface between the positive - electrode sheet and the solid - state electrolyte, the edge lithium deposition is reduced.

[0029] Please refer to Figures 1 to 5 , an all - solid - state battery cell 100 according to an embodiment of the present invention includes a positive - electrode current collector 110, a positive - electrode sheet 120, a solid - state electrolyte 130, a lithium - metal negative - electrode sheet 140, and a negative - electrode current collector 150 that are sequentially stacked.

[0030] Among them, the positive electrode current collector 110 is a commonly used positive electrode current collector in the field of all-solid-state battery cells, and the present invention places no restrictions on the positive electrode current collector 110. In some embodiments, the positive electrode current collector 110 may be made of high-purity aluminum foil or aluminum alloy foil with a purity of not less than 99.6% and a thickness of 10 μm to 20 μm. In some embodiments, the surface of the aluminum foil may be anodized to form a nanoscale alumina layer to enhance its corrosion resistance and the interfacial bonding force with the positive electrode material. In some embodiments, the aluminum alloy foil may contain trace amounts of titanium (Ti) or silicon (Si) elements to improve mechanical strength and high-temperature stability.

[0031] Among them, the positive electrode sheet 120 is a commonly used positive electrode sheet 120 in the field of all-solid-state battery cells, and the present invention places no restrictions on the positive electrode sheet 120. In some embodiments, the positive electrode sheet includes active materials, conductive agents, binders, etc. The positive electrode active materials can be those well-known in the art for use in the positive electrodes of lithium-ion batteries. By way of example, the positive electrode active materials may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present invention is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3Mn 1 / 3 O2 (which can also be abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05at least one of O2) and its modified compounds, etc. Examples of the lithium-containing phosphate with olivine structure may include but are not limited to lithium iron phosphate LiFePO4 (which may also be simply referred to as LFP), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Among them, the mass ratio of the positive electrode active material can be but is not limited to 80% to 95%. The conductive agent includes any one or a combination of at least two of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers. The above are all common conductive agents in the art, only for examples, not limitations. Among them, the mass ratio of the conductive agent can be but is not limited to 3% to 10%. The binder includes any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyvinyl chloride, polystyrene, polyoxymethylene, polycarbonate, polyamide, acrylic plastics, other polyolefins and their copolymers, polysulfone, polyphenylene ether, or carboxymethyl cellulose. The above are all common binders in the art, only for examples, not limitations. Among them, the mass ratio of the binder can be but is not limited to 2% to 8%.

[0032] Further, the positive electrode sheet 120 includes a first sub-positive electrode sheet 121 and a second sub-positive electrode sheet 122 stacked in a direction away from the positive electrode current collector 110. The projection of the first sub-positive electrode sheet 121 on the solid electrolyte 130 covers the projection of the second sub-positive electrode sheet 122 on the solid electrolyte 130, and the projection area of the first sub-positive electrode sheet 121 on the solid electrolyte 130 is larger than the projection area of the second sub-positive electrode sheet 122 on the solid electrolyte 130.

[0033] Among them, the solid electrolyte 130 is a commonly used solid electrolyte in the field of all-solid-state battery cells, and the present invention does not limit the solid electrolyte 130. In some embodiments, the solid electrolyte 130 can be a sulfide-based solid electrolyte, such as Li2S-P2S5, Li2S-P2S5-MS x (where M is Si, Ge, and Sn and 0 ≤ x ≤ 2), Li 3.4 Si 0.4 P 0.6 S4, Li 10 GeP2S 11.7 O 0.3 、Li 9.6 P3S 12 、Li7P3S 11 、Li9P3S9O3、Li 10.35 Si 1.35 P 1.65 S 12 、Li 9.81 Sn 0.81 P 2.19 S 12, Li 10 (Si 0.5 Ge 0.5 )P2S 12 , Li(Ge 0.5 Sn 0.5 )P2S 12 , Li(Si 0.5 Sn 0.5 )P2S 12 , Li 10 GeP2S 12 (LGPS), Li6PS5X (where X is Cl, Br, or I), Li7P2S8I, Li 10.35 Ge 1.35 P 1.65 S 12 , Li 3.25 Ge 0.25 P 0.75 S4, Li 10 SnP2S 12 , Li 10 SiP2S 12 , Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 etc. In some embodiments, the thickness of the electrolyte layer is 30 μm to 100 μm and can be prepared by cold pressing or solution casting. In some other embodiments, the solid electrolyte 130 can be replaced with an oxide-based electrolyte, such as perovskite-type, garnet-type, LISICON-type, NASICON-type, etc. Among them, the perovskite-type solid electrolyte material is preferably lithium lanthanum titanate / lithium titanate (Li 0.33 La 0.56 TiO3, LLTO), the garnet-type solid electrolyte material is preferably lithium lanthanum zirconium oxide / lithium zirconate (Li7La3Zr2O 12 , LLZO), and the NASICON-type (sodium superionic conductor) solid electrolyte material is preferably lithium aluminum titanium phosphate LATP (Li 1.3 Al 0.3 Ti 1.7 (PO4)3). In some other embodiments, the solid electrolyte 130 can be replaced with a halide-based electrolyte, such as Li2CdCl4, Li2MgCl4, Li2CdI4, Li2ZnI4, Li3OCl, LiI, Li5ZnI4, Li3OCl 1-x Br x(where 0 < x < 1), etc. In some other embodiments, the solid-state electrolyte 130 can be replaced by a polymer-based electrolyte, such as a composite system of a polymer electrolyte and a lithium salt. The present application does not particularly limit the type of the polymer electrolyte. On the basis of not departing from the inventive concept of the present application, any known polymer electrolyte can be used in the present application. It is only a schematic example, rather than a limitation of the protection scope. The polymer electrolyte includes but is not limited to one or several of polyolefin polymers, polyacrylonitrile polymers, polycarboxylate polymers, polyether polymers, polysulfide polymers, and polyurethane polymers. The polyolefin polymer can be selected from one or several of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride hexafluoropropylene copolymer (PVDF-HFP), polyethylene (PE), and polypropylene (PP). The polyacrylonitrile polymer is selected from polyacrylonitrile (PAN). The polycarboxylate polymer is selected from polymethyl methacrylate (PMMA). The polyether polymer can be selected from polyethylene oxide (PEO) and / or polyethylene oxide (PEO). The polysulfide polymer can be selected from polyphenylene sulfide (PPS). The polyurethane polymer can be selected from polyurethane (PU). The present application does not particularly limit the type of the lithium salt. On the basis of not departing from the inventive concept of the present application, any known lithium salt can be used in the present application. It is only a schematic example, rather than a limitation of the protection scope. The lithium salt includes any one or a combination of at least two of lithium hexafluorophosphate, lithium perchlorate, lithium tetrachloroaluminate, lithium iodide, lithium bromide, lithium thiocyanate, lithium tetrafluoroborate, lithium difluorooxalate borate, lithium tetraphenylborate, bis(oxalato)borate lithium, lithium tetrafluorooxalate phosphate, lithium nitrate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonylimide), or lithium bis(fluorosulfonylimide). In some embodiments, the mass ratio of the lithium salt in the composite system of the polymer electrolyte and the lithium salt can be but is not limited to 10% - 30%.

[0034] Among them, the lithium metal negative electrode sheet 140 is one or more of lithium metal, lithium alloy or lithium metal composite layer commonly used in the field of all-solid-state battery cells. The present invention does not limit the lithium metal negative electrode sheet 140.

[0035] In some embodiments, the lithium metal negative electrode sheet 140 is a high-purity lithium foil (purity ≥ 99.9%), and the thickness can be but is not limited to 20μm - 100μm. In some specific embodiments, the surface of the lithium foil can be coated with an artificial solid electrolyte interface layer (such as LiN or LiF), and the thickness of the artificial solid electrolyte interface layer is 50nm - 200nm to inhibit the growth of lithium dendrites and reduce the interface impedance. In some embodiments, the lithium metal is deposited on the surface of the copper current collector in the form of a three-dimensional porous structure, the porosity is 40% - 60%, and the pore size distribution is 1μm - 10μm to relieve the volume expansion during the charge and discharge process.

[0036] In some embodiments, the lithium metal negative electrode sheet 140 is a lithium alloy, and the lithium alloy may be an alloy of lithium and M, where M is selected from one or more of silicon, carbon, boron, sulfur, tellurium, sodium, magnesium, aluminum, indium, tin, gallium, yttrium, gold, silver, copper, lead, bismuth, germanium, titanium, chromium, cobalt, tungsten, iron, niobium, nickel, barium, cadmium, cesium, calcium, manganese, nitrogen, platinum, thallium, strontium, zinc, antimony, zirconium; in some specific embodiments, the content of lithium in the lithium alloy may be 70% or more, and further, the content of lithium may be 90% or more.

[0037] In some embodiments, the lithium metal negative electrode sheet 140 is a lithium metal composite layer, and the lithium metal composite layer includes a metal lithium layer and a functional layer with a three-dimensional skeleton arranged in a stacked manner. In some specific embodiments, the fibrillated binder is mixed with the functional powder and roll-pressed to obtain a functional layer with a three-dimensional skeleton. In some specific embodiments, the total number of layers of the metal lithium layer and the functional layer is 2 to 50 layers. Further preferably, the total number of layers of the metal lithium layer and the functional layer in the layered metal lithium composite negative electrode is 2 to 20 layers, wherein the metal lithium layer and the functional layer are alternately arranged in a stacked manner. In some specific embodiments, the binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyethylene, styrene-butadiene rubber, nitrile rubber, sodium carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, sodium alginate, polyaniline, polypyrrole, polyethylene oxide, polyvinylpyrrolidone, poly(ethylene carbonate), poly(propylene carbonate), poly(trimethylene carbonate). In some specific embodiments, the mass ratio of the functional powder to the binder is (0.1 to 96):(4 to 99.9); preferably, the mass ratio of the functional powder to the binder is (5 to 50):(50 to 95); more preferably, the mass ratio of the functional powder to the binder is (5 to 10):(90 to 95). In some embodiments, the inorganic powder includes one or more mixtures of conductive metals, conductive carbon, oxides, sulfides, nitrides, carbides, fluorides, solid electrolytes, or the inorganic powder is a composite formed by two or more of conductive metals, conductive carbon, oxides, sulfides, nitrides, carbides, fluorides, solid electrolytes. In some specific embodiments, the D50 of the functional powder is 10 nm to 10 μm, preferably 5 nm to 5 μm; in some specific embodiments, the particle size of the binder is 100 μm to 800 μm, preferably 100 μm to 800 μm.In some specific embodiments, the conductive metal is a lithiumophilic metal or a lithiumophilic semimetal, including one or more of zinc powder, tin powder, aluminum powder, silver powder, gold powder, silicon powder, black phosphorus, etc.; in some specific embodiments, the conductive carbon includes one or more of graphite, carbon black, carbon fiber, carbon nanotube, graphene, fullerene, heteroatom-doped carbon; in some specific embodiments, the oxide includes one or more of magnesium oxide, aluminum oxide, silicon dioxide, silicon monoxide, calcium oxide, titanium dioxide, vanadium oxide, manganese oxide, iron oxide, tin oxide, copper oxide, zinc oxide, molybdenum oxide, niobium oxide, tungsten oxide, bismuth oxide, graphene oxide, barium titanate, sodium niobate; in some specific embodiments, the sulfide includes one or more of iron sulfide, cobalt sulfide, nickel sulfide, manganese sulfide, molybdenum sulfide, cadmium sulfide, tin sulfide, bismuth sulfide, tungsten sulfide; in some specific embodiments, the nitride includes one or more of lithium nitride, boron nitride, aluminum nitride, silicon nitride, calcium nitride, titanium nitride, magnesium nitride, manganese nitride, tungsten nitride, zirconium nitride, molybdenum nitride, vanadium nitride, chromium nitride, zirconium nitride, niobium nitride, tantalum nitride, tungsten nitride; in some specific embodiments, the carbide includes one or more of boron carbide, silicon carbide, calcium carbide, chromium carbide, tantalum carbide, titanium carbide, tungsten carbide; in some specific embodiments, the fluoride includes one or more of iron fluoride, lithium fluoride, calcium fluoride.

[0038] Among them, the negative electrode current collector 150 is a negative electrode current collector commonly used in the field of all-solid-state battery cells, and the present invention does not limit the negative electrode current collector 150. In some embodiments, the negative electrode current collector 150 is an electrolytic copper foil with a purity

[0039] ≥99.99%, and the thickness is 8 μm to 15 μm. Further, the surface of the copper foil can be chemically polished to have a roughness (Ra) ≤ 0.5 μm to enhance the uniform deposition of lithium metal. In addition, the copper foil can be pre-coated with a carbon-based buffer layer (such as graphene or hard carbon) with a thickness of 0.5 μm to 2 μm to reduce the local current density and inhibit lithium dendrites.

[0040] Among them, the all-solid-state battery cell 100 further includes an insulating pad 160. The insulating pad 160 is sleeved on the periphery of the second sub-positive electrode sheet 122, and the two surfaces of the insulating pad 160 are respectively in contact with the first sub-positive electrode sheet 121 and the solid electrolyte 130. Combining the foregoing, the projection of the first sub-positive electrode sheet 121 on the solid electrolyte 130 covers the projection of the second sub-positive electrode sheet 122 on the solid electrolyte 130, and the projected area of the first sub-positive electrode sheet 121 on the solid electrolyte 130 is larger than the projected area of the second sub-positive electrode sheet 122 on the solid electrolyte 130. Therefore, when the insulating pad 160 is sleeved on the periphery of the second sub-positive electrode sheet 122, the two surfaces of the insulating pad 160 can be respectively in contact with the first sub-positive electrode sheet 121 and the solid electrolyte 130.

[0041] In the all-solid-state battery cell 100 of this embodiment, by providing an insulating pad 160 on the positive electrode side at the interface between the positive electrode sheet 120 and the solid electrolyte 130, on the one hand, the contact area between the positive electrode sheet 120 and the solid electrolyte 130 is reduced, and the area allowing current passage in the overhang region on the negative electrode side is decreased; on the other hand, the stress distribution after pressure application at the negative electrode interface is improved, and the current density distribution in the negative electrode region is changed. Therefore, the interfacial current of the all-solid-state battery under pressure can be improved, and the problem of lithium deposition at the edge can be avoided.

[0042] On the basis of the foregoing embodiment, the first sub-positive electrode sheet 121 and the second sub-positive electrode sheet 122 are integrally formed. In this way, the first sub-positive electrode sheet 121 and the second sub-positive electrode sheet 122 are a whole, which is beneficial to current passage.

[0043] On the basis of the foregoing embodiment, the outer ring dimension of the insulating pad 160 is the same as the outer perimeter dimension of the first sub-positive electrode sheet 121, and the inner ring dimension of the insulating pad 160 is the same as the outer perimeter dimension of the second sub-positive electrode sheet 122. At this time, the sum of the projected area of the insulating pad 160 on the solid electrolyte 130 and the projected area of the second sub-positive electrode sheet 122 on the solid electrolyte 130 is equal to the projected area of the first sub-positive electrode sheet 121 on the solid electrolyte 130. First of all, this can accurately control the interfacial contact area, that is, through the size matching between the insulating pad 160 and the positive electrode sheet 120, the effective contact area between the positive electrode sheet 120 and the solid electrolyte 130 is accurately defined, so that the current density is evenly distributed at the interface, avoiding the problem of lithium metal negative electrode edge lithium deposition caused by too high local current. Secondly, it can homogenize the pressure distribution, that is, the geometric matching design of the insulating pad 160 ensures that the stress is evenly transmitted along the positive electrode sheet 120 - solid electrolyte 130 interface during the pressure application process, reducing the local stress concentration caused by size deviation, thereby improving the solid-solid interface contact integrity and suppressing the abnormal deposition of lithium ions on the negative electrode side. Thirdly, it can also inhibit the formation of lithium dendrites, that is, by balancing the contact area and the current distribution, this design effectively reduces the electric field strength in the negative electrode edge region, weakens the nucleation driving force of lithium dendrites, and at the same time, the physical barrier effect of the insulating pad 160 further restricts the lateral diffusion path of lithium ions. Finally, it can also improve the structural stability of the all-solid-state battery cell 100, that is, the size consistency between the insulating pad 160 and the positive electrode sheet 120 prevents the misalignment of the all-solid-state battery cell 100 components due to thermal expansion or mechanical vibration during charge and discharge cycles, maintains the tight fit between the layers of the all-solid-state battery cell 100, and extends the battery cycle life.

[0044] On the basis of the foregoing embodiment, the thickness of the insulating pad 160 is the same as the thickness of the second sub-positive electrode sheet 122. This is beneficial for the two surfaces of the insulating pad 160 to better abut against the first sub-positive electrode sheet 121 and the solid electrolyte 130.

[0045] On the basis of the foregoing embodiments, the thickness of the insulating pad 160 is 20 μm to 30 μm. Further, the thickness of the insulating pad 160 can be, but is not limited to, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, or 30 μm.

[0046] On the basis of the foregoing embodiments, half of the difference between the outer and inner circles of the insulating pad 160 is 1.5 mm to 2.5 mm. Further, half of the difference between the outer and inner circles of the insulating pad 160 can be, but is not limited to, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, or 2.5 mm.

[0047] On the basis of the foregoing embodiments, the insulating pad 160 is a polymer elastomer, and the specific materials can include one or a combination of rubber, polyester, and substituted / unsubstituted polyolefins. In some specific embodiments, the rubber can be common styrene-butadiene rubber, nitrile rubber, chloroprene rubber, ethylene-propylene rubber, silicone rubber, fluororubber, etc.; in some specific embodiments, the substituted / unsubstituted polyolefins can be selected from common polyethylene, polytetrafluoroethylene, polypropylene, polyvinyl chloride, etc.; in some specific embodiments, the polyester can be selected from polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyarylate (PAR), etc.; in some specific embodiments, the materials of the polymer elastomer can also be selected from polyurethane, polyamide, ABS, etc. The above types of polymer elastomer materials all have good insulation performance and wear resistance, and have good corrosion resistance and high and low temperature resistance, which can effectively maintain the long service life of the insulating pad 160; at the same time, the excellent elasticity of the polymer elastomer material can effectively relieve the impact during the production and use of the battery, and further improve the service life.

[0048] On the basis of the foregoing embodiments, the ratio of the thickness of the second sub-positive electrode sheet 122 to the thickness of the first sub-positive electrode sheet 121 is 0.182 to 0.3. Further, the ratio of the thickness of the second sub-positive electrode sheet 122 to the thickness of the first sub-positive electrode sheet 121 can be, but is not limited to, 0.182, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.3.

[0049] On the basis of the foregoing embodiments, the ratio of the projected area of the second sub-positive electrode sheet 122 on the solid electrolyte 130 to the projected area of the first sub-positive electrode sheet 122 on the solid electrolyte 130 is 0.766 to 0.856.

[0050] The all-solid-state battery cell of the technical solution of the present invention includes an insulating pad, which on the one hand reduces the contact area between the positive electrode sheet and the solid electrolyte, and the area of the overhang region on the negative electrode side that allows current to pass through is reduced; on the other hand, it also improves the stress distribution after pressurization at the negative electrode interface and changes the current density distribution in the negative electrode region. The all-solid-state battery cell of the present invention reduces edge lithium plating from the above two aspects.

[0051] A pouch-type all-solid-state lithium metal battery in one embodiment includes the all-solid-state battery cell of any of the above.

[0052] The all-solid-state lithium metal battery of the technical solution of the present invention includes the above all-solid-state battery cell. The all-solid-state battery cell includes an insulating pad, which on the one hand reduces the contact area between the positive electrode sheet and the solid electrolyte, and the area of the overhang region on the negative electrode side that allows current to pass through is reduced; on the other hand, it also improves the stress distribution after pressurization at the negative electrode interface and changes the current density distribution in the negative electrode region. The pouch-type all-solid-state lithium metal battery of the present invention reduces edge lithium plating from the above two aspects.

[0053] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0054] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A all-solid-state battery cell, characterized in that, The all-solid-state battery cell includes a positive current collector, a positive electrode sheet, a solid electrolyte, a lithium metal negative electrode sheet, and a negative current collector that are sequentially stacked; Among them, the positive electrode sheet includes a first sub-positive electrode sheet and a second sub-positive electrode sheet stacked in a direction away from the positive current collector. The projection of the first sub-positive electrode sheet on the solid electrolyte covers the projection of the second sub-positive electrode sheet on the solid electrolyte, and the projection area of the first sub-positive electrode sheet on the solid electrolyte is larger than the projection area of the second sub-positive electrode sheet on the solid electrolyte; The all-solid-state battery cell further includes an insulating pad. The insulating pad is sleeved on the periphery of the second sub-positive electrode sheet, and two surfaces of the insulating pad are respectively in contact with the first sub-positive electrode sheet and the solid electrolyte.

2. The all-solid-state battery cell according to claim 1, characterized in that, The first sub-positive electrode sheet and the second sub-positive electrode sheet are integrally formed.

3. The all-solid-state battery cell according to claim 1, characterized in that, The outer dimension of the insulating pad is the same as the outer dimension of the first sub-positive electrode sheet, and the inner dimension of the insulating pad is the same as the outer dimension of the second sub-positive electrode sheet.

4. The all-solid-state battery cell according to claim 1, wherein, The thickness of the insulating pad is the same as the thickness of the second sub-positive electrode sheet.

5. The all-solid-state battery cell according to claim 1, wherein The thickness of the insulating pad is 20 μm to 30 μm.

6. The all-solid-state battery cell according to claim 1, wherein Half of the difference between the outer circle and the inner circle of the insulating pad is 1.5 mm to 2.5 mm.

7. The all-solid-state battery cell according to claim 1, wherein, The material of the insulating pad includes one or a combination of rubber, polyethylene, and polytetrafluoroethylene.

8. The all-solid-state battery cell according to claim 1, characterized in that, The ratio of the thickness of the second sub-positive electrode sheet to the thickness of the first sub-positive electrode sheet is 0.182 to 0.

3.

9. The all-solid-state battery cell according to claim 1, wherein The ratio of the projection area of the second sub-positive electrode sheet on the solid electrolyte to the projection area of the first sub-positive electrode sheet on the solid electrolyte is 0.766 to 0.

856.

10. A soft-pack all-solid-state lithium metal battery, characterized in that, An all-solid-state battery cell according to any one of claims 1 to 9 is included.

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