Solid-state battery, preparation method thereof and electric equipment

Abstract

The invention discloses a solid-state battery, a preparation method thereof and electric equipment. The solid-state battery comprises a solid-state battery cell, a functional film and a packaging film, the functional film is located between the solid-state battery cell and the packaging film, and the functional film comprises sulfite. The functional film is arranged on the outer side of the solid-state battery, sulfite in the functional film can react with oxygen and adsorb oxygen separated out in the cycle process of the positive electrode material in time, so that the risk of thermal runaway of the solid-state battery is reduced, and the sulfite can react with hydrogen sulfide, so that the hydrogen sulfide gas which is possibly generated is eliminated.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to solid-state batteries, their preparation methods, and electrical devices. Background Technology

[0002] Driven by the need for battery safety, solid-state batteries have experienced rapid development, with sulfide solid-state batteries showing promising application prospects. However, sulfide solid-state batteries are not absolutely safe, posing two major safety hazards: 1) During charging and discharging, lattice oxygen may be released from the cathode material (such as NCM ternary materials). The amount of oxygen released is exponentially related to the number of cycles, and there is a risk of deflagration when the local oxygen concentration reaches 4%; 2) The reaction of sulfide solid electrolyte with trace amounts of moisture can generate toxic H2S gas, and conventional aluminum-plastic encapsulation films have an H2S blocking efficiency of less than 50%.

[0003] Current research on suppressing oxygen release from cathode materials mainly focuses on modification methods such as doping and coating to reduce oxygen evolution, but the actual modification effect is not significant. There is even less research on the potential leakage of hydrogen sulfide gas from batteries.

[0004] Therefore, current solid-state batteries, their fabrication methods, and electrical devices still need improvement. Summary of the Invention

[0005] This application aims to at least partially alleviate or resolve at least one of the aforementioned problems.

[0006] In one aspect of this application, a solid-state battery is proposed. In some embodiments of this application, the solid-state battery includes a solid-state cell, a functional film, and an encapsulation film. The functional film is located between the solid-state cell and the encapsulation film, and the functional film includes sulfite. By providing the functional film on the outside of the solid-state battery, the sulfite in the functional film can react with oxygen, promptly adsorbing oxygen released during the cycling of the positive electrode material, thereby reducing the risk of thermal runaway in the solid-state battery. Furthermore, the sulfite can also react with hydrogen sulfide, thereby eliminating any hydrogen sulfide gas that may be generated.

[0007] In some embodiments of this application, the sulfite includes one or more of sodium sulfite, potassium sulfite, and calcium sulfite. All of the above sulfites can react with oxygen and hydrogen sulfide, thereby adsorbing oxygen and reducing the potential generation of hydrogen sulfide gas, thus lowering the risk of thermal runaway in solid-state batteries and the risk of hydrogen sulfide gas leakage.

[0008] In some embodiments of this application, the functional film covers at least a portion of the surface of the solid-state battery cell. This facilitates the reaction of sulfites in the functional film with oxygen and / or hydrogen sulfide, thereby promoting rapid removal of oxygen and / or hydrogen sulfide.

[0009] In some embodiments of this application, the D50 particle size of the sulfite is 20nm-200nm, and / or the specific surface area of ​​the sulfite is ≥35m². 2 / g. This facilitates the rapid adsorption and removal of oxygen and / or hydrogen sulfide gas.

[0010] In some embodiments of this application, the functional membrane further includes a polymer. This improves the overall performance of the functional membrane, thereby contributing to further enhancements in the performance of solid-state batteries.

[0011] In some embodiments of this application, the functional membrane satisfies at least one of the following conditions: the mass ratio of sulfite to polymer in the functional membrane is (50-85):(10-50); the melting temperature of the polymer is ≥200°C; the polymer includes one or more of polytetrafluoroethylene, polycarbonate, polyethylene terephthalate, polybenzimidazole, polyether ether ketone, and polyimide.

[0012] In some embodiments of this application, the functional membrane further includes a water-absorbing oxide, which comprises one or more of Al2O3, CaO, MgO, BaO, SiO2, and CuSO4. These materials possess a certain degree of water absorption, which can improve the environmental adaptability of solid-state batteries, enabling them to maintain good cycle stability even in high-humidity environments.

[0013] In some embodiments of this application, the mass percentage of water-absorbing oxide in the functional membrane is a, where 0 < a ≤ 10%. A water-absorbing oxide content within this range can at least partially improve the cycle stability of the solid-state battery in high-humidity environments.

[0014] In some embodiments of this application, the thickness of the functional film is 8μm-25μm. This is beneficial for further improving the overall performance of the solid-state battery.

[0015] In some embodiments of this application, the solid-state battery cell includes a positive electrode, an electrolyte layer, and a negative electrode, wherein the electrolyte layer is located between the positive electrode and the negative electrode, and the electrolyte layer includes a sulfide electrolyte; and / or, the encapsulation film includes an aluminum-plastic film.

[0016] In another aspect of this application, a method for preparing the aforementioned solid-state battery is proposed. In some embodiments of this application, the method for preparing the aforementioned solid-state battery includes: bonding a functional film to a solid-state cell, covering it with an outer encapsulation film, and performing vacuum encapsulation to obtain the solid-state battery; wherein the functional film comprises sulfite. Therefore, this solid-state battery possesses all the features and advantages of the aforementioned solid-state battery, which will not be elaborated further here. This method is simple to operate, easy to implement, and beneficial for improving the yield of solid-state battery preparation.

[0017] In some embodiments of this application, the method for preparing the functional membrane includes: mixing sulfite, a polymer, and a solvent to obtain a slurry, thereby forming a functional membrane; or mixing sulfite, a polymer, a water-absorbing oxide, and a solvent to obtain a slurry, thereby forming a functional membrane. Thus, a functional membrane capable of simultaneously adsorbing oxygen and hydrogen sulfide gas can be obtained.

[0018] In another aspect, this application proposes an electrical device. In some embodiments of this application, the electrical device includes the solid-state battery described above. Therefore, this electrical device possesses all the features and advantages of the solid-state battery described above, which will not be repeated here. In general, this electrical device is less prone to thermal runaway during use and is less likely to cause hydrogen sulfide gas leakage. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1 A partial structural schematic diagram of a solid-state battery according to an embodiment of this application is shown;

[0021] Figure 2 A partial structural schematic diagram of a solid-state battery according to another embodiment of this application is shown.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1: Solid-state battery cell; 2: Functional film; 3: Encapsulation film. Detailed Implementation

[0024] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0025] In one aspect of this application, a solid-state battery is proposed. In some embodiments of this application, reference is made to... Figure 1 and Figure 2 A solid-state battery can include a solid-state cell 1, a functional film 2, and an encapsulation film 3. The functional film 2, located between the solid-state cell 1 and the encapsulation film 3, comprises sulfite. During charging and discharging, the cathode material may release lattice oxygen, with the amount of oxygen released being exponentially related to the number of cycles. When the local oxygen concentration in the solid-state battery reaches 4%, there is a risk of deflagration. The sulfite in the functional film can react with oxygen, thereby reducing the amount of oxygen in the solid-state battery and thus reducing the risk of thermal runaway. Additionally, hydrogen sulfide gas may be generated in the solid-state battery. Encapsulation films such as aluminum-plastic films have low barrier efficiency for hydrogen sulfide gas, thus potentially leading to hydrogen sulfide gas leakage. The sulfite in the functional film can react with hydrogen sulfide gas, effectively removing it and reducing the risk of hydrogen sulfide gas leakage in the solid-state battery.

[0026] In some embodiments of this application, reference is made to Figure 1 and Figure 2 The functional membrane 2 can cover at least a portion of the surface of the solid-state battery cell 1. This facilitates the rapid adsorption and removal of oxygen and / or hydrogen sulfide by the functional membrane, thereby enhancing the protective effect of the functional membrane on the solid-state battery cell.

[0027] In some specific embodiments of this application, reference is made to Figure 1 The functional membrane 2 can cover part of the surface of the solid cell 1, which is conducive to the rapid removal of oxygen and hydrogen sulfide gas released in this part of the solid battery.

[0028] In other specific embodiments of this application, reference is made to Figure 2 The functional film 2 can completely cover the surface of the solid-state cell 1.

[0029] In some embodiments of this application, the solid-state battery cell 1 can be a square battery cell, and the functional film 2 can cover the six surfaces of the square battery cell. In other embodiments of this application, the solid-state battery cell 1 can be a cylindrical battery cell, and the functional film 2 can cover the curved surface and two planes of the cylindrical battery cell.

[0030] In some embodiments of this application, the sulfite may include one or more of sodium sulfite (Na₂SO₃), potassium sulfite (K₂SO₃), and calcium sulfite (CaSO₃). The reaction equations for the above-mentioned sulfite with oxygen or hydrogen sulfide gas are as follows:

[0031] 2Na₂SO₃ + O₂ → 2Na₂SO₄;

[0032] Na2SO3+3H2S→3S↓+Na2S+3H2O;

[0033] 2K₂SO₃ + O₂ → 2K₂SO₄;

[0034] K2SO3+3H2S→3S↓+K2S+3H2O;

[0035] 2CaSO3 + O2 → 2CaSO4;

[0036] CaSO3+3H2S→3S↓+CaS+3H2O.

[0037] The aforementioned sulfites can all react with oxygen and hydrogen sulfide to remove oxygen and hydrogen sulfide gas that may be released from solid-state batteries, thereby reducing the risk of thermal runaway in solid-state batteries and the risk of hydrogen sulfide gas leakage from solid-state batteries.

[0038] In some embodiments of this application, the sulfite in the functional membrane may include sodium sulfite, potassium sulfite, or calcium sulfite. In other embodiments of this application, the sulfite in the functional membrane may include two or three of sodium sulfite, potassium sulfite, and calcium sulfite.

[0039] In some embodiments of this application, the sulfites in the functional membrane can be nanoscale in size. Nanoscale sulfites have a high specific surface area, which is beneficial for adsorbing oxygen and hydrogen sulfide gases generated by the solid-state battery cell and removing oxygen and hydrogen sulfide through chemical reactions.

[0040] In some embodiments of this application, the D50 particle size of the sulfite can be 20nm-200nm, for example, the D50 particle size of the sulfite can be 20nm, 50nm, 70nm, 100nm, 120nm, 150nm, 180nm, or 200nm. This facilitates the adsorption and removal of oxygen and hydrogen sulfide, thereby further reducing the risk of thermal runaway in solid-state batteries and the risk of hydrogen sulfide gas leakage.

[0041] In this application, D50 particle size refers to the particle size corresponding to a cumulative particle size distribution percentage of 50% in a sample. Its physical meaning is that particles larger than D50 account for 50% of the total, and particles smaller than D50 also account for 50%. D50 particle size is also called median diameter or median particle size.

[0042] In some embodiments of this application, the specific surface area of ​​sulfite can be ≥35m². 2 / g, for example, the specific surface area of ​​sulfite can be 35m². 2 / g、40m 2 / g、45m 2 / g, 50m 2 / g、55m 2 / g etc. Therefore, sulfites have a large specific surface area, which is beneficial to improving the adsorption effect of sulfites on oxygen and hydrogen sulfide gases, thus facilitating the removal of oxygen and hydrogen sulfide gases.

[0043] In some embodiments of this application, in addition to sulfites, the functional membrane 2 may also include a polymer. The polymer can improve the overall performance of the functional membrane, thereby contributing to further improvements in the performance of the solid-state battery. For example, the polymer can improve the flatness of the functional membrane, thus facilitating a smooth fit between the functional membrane and the solid-state battery cell.

[0044] In some embodiments of this application, the mass ratio of sulfite to polymer in the functional membrane 2 can be (50-85):(10-50), for example, 50:50, 60:40, 70:30, 75:25, 80:20, 85:15, etc. A suitable mass ratio of sulfite to polymer is beneficial for improving the overall performance of the functional membrane.

[0045] In some embodiments of this application, the melting temperature (Tm) of the polymer can be ≥200°C. For example, the melting temperature of the polymer can be 200°C, 220°C, 230°C, 250°C, 265°C, etc. A higher melting temperature of the polymer is beneficial to improving the high-temperature resistance of the functional film, thereby further improving the overall performance of the solid-state battery.

[0046] Melting temperature (Tm) is a key parameter characterizing the thermal properties of crystalline polymers. It refers to the critical temperature at which the macromolecular chain structure transforms from a three-dimensional long-range ordered state to a disordered viscous flow state.

[0047] In some embodiments of this application, the polymer includes one or more of polytetrafluoroethylene, polycarbonate, polyethylene terephthalate, polybenzimidazole, polyetheretherketone, and polyimide. These polymers have high melting temperatures and good high-temperature resistance, which is beneficial for improving the structural stability of solid-state batteries at higher temperatures.

[0048] In some specific embodiments of this application, the polymer in the functional membrane may include polytetrafluoroethylene, polycarbonate, polyethylene terephthalate, polybenzimidazole, polyetheretherketone, or polyimide. In other specific embodiments of this application, the polymer in the functional membrane may include two or more of polytetrafluoroethylene, polycarbonate, polyethylene terephthalate, polybenzimidazole, polyetheretherketone, and polyimide.

[0049] In some specific embodiments of this application, in addition to sulfites and polymers, the functional membrane may also include a water-absorbing oxide, which may include one or more of Al2O3, CaO, MgO, BaO, SiO2, and CuSO4. In some embodiments, the water-absorbing oxide may include Al2O3, CaO, MgO, BaO, SiO2, or CuSO4. In other embodiments, the water-absorbing oxide may include two or more of Al2O3, CaO, MgO, BaO, SiO2, and CuSO4. The above materials have a certain water-absorbing effect and can adsorb water molecules generated in the solid-state battery, thereby reducing the adverse effects of water molecules on the solid-state battery.

[0050] In some embodiments of this application, the mass percentage of water-absorbing oxide in the functional membrane is 'a', where 0 < a ≤ 10%, based on the total mass of the functional membrane. For example, 'a' can be 1%, 3%, 5%, 8%, 10%, etc. The water-absorbing oxide at the above-mentioned content can adsorb water molecules near the functional membrane, thereby reducing the adverse effects of water molecules on the solid-state battery.

[0051] In some embodiments of this application, the mass ratio of sulfite, polymer, and water-absorbing oxide in the functional membrane can be (50-85):(10-50):(0-10), for example, 50:40:10, 60:30:10, 60:35:5, 70:25:5, 75:15:10, 80:15:5, 85:10:5, etc. Meeting these conditions improves the removal efficiency of oxygen and hydrogen sulfide gas, and also enhances the membrane's high-temperature resistance and water absorption.

[0052] In some embodiments of this application, the thickness of the functional film 2 can be 8μm-25μm, for example, the thickness of the functional film 2 can be 8μm, 10μm, 15μm, 20μm, 25μm, etc. A thickness within the above range is beneficial for removing oxygen and hydrogen sulfide gas from the solid-state battery, and the functional film of the above thickness does not significantly increase the volume and production cost of the solid-state battery.

[0053] In some embodiments of the present invention, the solid-state battery cell 1 includes a positive electrode, an electrolyte layer, and a negative electrode, wherein the electrolyte layer is located between the positive electrode and the negative electrode.

[0054] In some embodiments of this application, the positive electrode may include a positive electrode active material layer and a positive electrode current collector, wherein the positive electrode active material layer is located on at least one side of the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material, a solid electrolyte material, a first conductive agent, and a first binder. The positive electrode current collector may include aluminum foil. In some embodiments, the positive electrode active material may include one or more of lithium nickel cobalt manganese oxide ternary materials (e.g., NCM811, NCM613, etc.), lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese aluminum oxide, lithium cobalt oxide, lithium manganese oxide, and lithium iron phosphate. The solid electrolyte material may include a sulfide electrolyte (e.g., Li...). 5.5 PS 4.5 Cl 1.5 The first conductive agent may include one or more of carbon black, carbon nanotubes, graphene, and carbon fibers (such as vapor-grown carbon fibers, VGCF, etc.). The first binder may include one or more of PTFE (polytetrafluoroethylene), PAA (polyacrylic acid), PVDF (polyvinylidene fluoride), SBR (styrene-butadiene rubber), NBR (nitrile rubber), and CMC (sodium carboxymethyl cellulose). The content of each component in the positive electrode active material layer is not specifically limited in this application; those skilled in the art can set and adjust it according to actual needs.

[0055] In some embodiments of this application, the negative electrode may include a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer is located on at least one side of the negative electrode current collector. The negative electrode active material layer may include a negative electrode active material, a solid electrolyte material, a second conductive agent, and a second binder. The negative electrode current collector may include copper foil. In some embodiments, the negative electrode active material may include at least one of silicon and graphite; the solid electrolyte material may include a sulfide electrolyte; the second conductive agent may include one or more of carbon black, carbon nanotubes, graphene, and carbon fibers; and the second binder may include one or more of NBR, PTFE, PAA, PVDF, SBR, and CMC. The content of each component in the negative electrode active material layer is not specifically limited in this application, and those skilled in the art can set and adjust it according to actual needs.

[0056] In some embodiments of this application, the electrolyte layer may include a sulfide electrolyte (e.g., Li). 5.5 PS 4.5 Cl 1.5 (e.g., Li6PS5Cl, etc.). In some embodiments, in addition to the sulfide electrolyte, the electrolyte layer may also include the binder NBR.

[0057] In some embodiments of this application, the encapsulation film 3 may include an aluminum-plastic film.

[0058] In some other embodiments of this application, the encapsulation film may also be made of metal.

[0059] In summary, this application incorporates a functional film on the outer side of the solid-state battery cell. The sulfites in the functional film can effectively adsorb oxygen released during the cycling process of the cathode material, thereby reducing the risk of thermal runaway in the solid-state battery. Furthermore, the sulfites can eliminate any hydrogen sulfide gas that may be generated, reducing the risk of hydrogen sulfide gas leakage from the solid-state battery. Traditional methods for addressing the oxygen evolution problem at the cathode involve cathode modification (e.g., coating), which reduces the specific capacity of the cathode, resulting in capacity loss per unit mass. In this application, a dynamic protection system is constructed on the outside of the battery cell using a functional film, eliminating the need for cathode modification and thus avoiding capacity loss caused by cathode modification. The composite functional film structure, combining flexibility and high barrier properties, provides safety protection for the solid-state battery cell.

[0060] In another aspect of this application, a method for preparing the aforementioned solid-state battery is proposed. In some embodiments of this application, the method for preparing the aforementioned solid-state battery includes the following steps: bonding a functional film to a solid-state cell, covering it with an outer encapsulation film, and performing vacuum encapsulation to obtain a solid-state battery; wherein the functional film comprises sulfite. The above method is simple to operate, easy to implement, and beneficial for improving the yield of solid-state battery preparation.

[0061] In some embodiments of this application, the method for preparing the functional membrane includes: mixing sulfite, a polymer and a solvent to obtain a slurry, thereby forming a functional membrane.

[0062] In some other embodiments of this application, the method for preparing the functional membrane includes: mixing sulfite, polymer, water-absorbing oxide and solvent to obtain a slurry to form a functional membrane.

[0063] The types and mass ratios of sulfites, polymers, and water-absorbing oxides have been explained in detail above and will not be repeated here.

[0064] In some embodiments, the solvent may include at least one of anhydrous ethanol and NMP (N-methylpyrrolidone).

[0065] In some embodiments, the slurry can be prepared into a functional membrane using a casting method. Of course, those skilled in the art can also use other methods to prepare functional membranes.

[0066] In some specific embodiments of this application, sulfite can be mixed with solvent (anhydrous ethanol and / or NMP) and ball-milled to obtain a first mixture; then polyimide solution (solvent is NMP), water-absorbing oxide and the first mixture can be mixed to form a slurry, and then the slurry can be coated by casting and cured to obtain a functional film.

[0067] This application does not specify the preparation methods for the positive and negative electrodes. Those skilled in the art can choose wet or dry processes to prepare the positive and negative electrodes according to the actual situation.

[0068] In some specific embodiments of this application, solid-state cells can be assembled in the order of positive electrode, electrolyte membrane, and negative electrode. The functional membrane is attached to the outside of the solid-state cell, and the outer layer is covered with an aluminum-plastic film. Vacuum encapsulation and isostatic pressing are then performed to obtain a solid-state battery.

[0069] In another aspect, this application proposes an electrical device. In some embodiments of this application, the electrical device includes the solid-state battery described above. Therefore, this electrical device possesses all the features and advantages of the solid-state battery described above, which will not be repeated here.

[0070] In some embodiments of this application, the electrical equipment may include mobile phones, computers, electric vehicles, electric bicycles, hybrid electric vehicles, energy storage devices, etc.

[0071] The present application will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments below are merely illustrative and do not limit the scope of the present application in any way. Furthermore, in the following embodiments, unless otherwise specified, the materials and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the later embodiments, conditions and methods known in the art can be used for processing.

[0072] Example 1

[0073] (1) Preparation of Na2SO3 / PI / CaO composite functional membrane (mass ratio of Na2SO3, PI, and CaO is 70:25:5):

[0074] (1.1) Na2SO3 with D50 = 50 nm was mixed with anhydrous ethanol at a mass ratio of 1:3 and ball-milled for 6 hours (300 rpm, zirconium oxide balls).

[0075] (1.2) Mixed slurry: Add polyimide / NMP solution (solid content of 20%) and Al2O3 nanoparticles to the mixture after ball milling in step (1.1), and ultrasonically disperse for 2 hours to obtain a slurry;

[0076] (1.3) Film formation process: The slurry was coated by casting, pre-dried at 80°C for 1 hour, and vacuum cured at 180°C for 4 hours to obtain a functional film with a thickness of 12μm.

[0077] (2) Assembling solid-state batteries:

[0078] (2.1) Method for preparing sulfide battery cells:

[0079] The cathode was prepared using a dry process: NCM ternary material (Ni, Co, Mn molar ratio of 8:1:1), LPSCl1.5, and VGCF were mixed in a mass ratio of 80:19:1. Then, 1 wt% PTFE (1% of the total mass of NCM ternary material, LPSCl1.5, and VGCF) was added to fibrousize the mixture. The resulting fiber was then processed using a roller press to obtain a size of 4 cm × 4 cm and an areal density of 4 mAh / cm³. 2 The dry-process positive electrode active material layer is composited with aluminum foil by hot pressing to obtain the positive electrode;

[0080] Electrolyte membranes were prepared using a wet process: the mass ratio of LPSCl to NBR was 98:2, xylene was used as the solvent, and the electrolyte membranes were obtained by slurry preparation and coating.

[0081] The anode was prepared by a wet process: Si, LPSCl, VGCF and NBR were mixed in a mass ratio of 70:20:8:2, and the mixture was slurryed and coated to obtain a wet silicon anode.

[0082] (2.2) Packaging:

[0083] Assemble (stack) the positive electrode, electrolyte membrane and negative electrode in sequence to form a solid cell. Then bond the functional membrane prepared in step (1) to the solid cell (the functional membrane fully covers the solid cell). Cover the outer layer with an aluminum-plastic film (the thickness of the aluminum-plastic film is 88μm). Then vacuum seal and perform isostatic pressure treatment at 500MPa to obtain a solid battery.

[0084] Example 2

[0085] Compared with Example 1, in Example 2, sodium sulfite in the functional membrane was replaced with CaSO3, and the other conditions were the same as in Example 1.

[0086] Example 3

[0087] Compared with Example 1, in Example 3, sodium sulfite in the functional membrane was replaced with potassium sulfite, and the other conditions were the same as in Example 1.

[0088] Example 4

[0089] Compared with Example 1, in the functional membrane of Example 4, the mass ratio of Na2SO3, PI and CaO is 85:10:5, and the other conditions are the same as in Example 1.

[0090] Example 5

[0091] Compared with Example 1, in the functional membrane of Example 5, the mass ratio of Na2SO3, PI and CaO is 50:40:10, and the other conditions are the same as in Example 1.

[0092] Example 6

[0093] Compared with Example 1, no water-absorbing oxide was added to the functional membrane of Example 6, the mass ratio of Na2SO3 to PI was 50:50, and the other conditions were the same as those of Example 1.

[0094] Example 7

[0095] Compared with Example 1, the thickness of the functional membrane in Example 7 is 8 μm, and the other conditions are the same as in Example 1.

[0096] Example 8

[0097] Compared to Example 1, the thickness of the functional membrane in Example 8 is 25 μm, while the other conditions are the same as in Example 1.

[0098] Comparative Example 1

[0099] Compared with Example 1, the solid-state battery cell does not have a functional film attached to its outer layer. Instead, it is directly covered with an aluminum-plastic film for vacuum sealing. All other conditions are the same as in Example 1.

[0100] Comparative Example 2

[0101] Compared to Example 1, sodium sulfite was replaced with ZnO, while other conditions remained the same as in Example 1.

[0102] The solid-state batteries prepared in each embodiment and comparative example were tested, and the test results are recorded in Table 1. The test conditions are as follows:

[0103] 1. Gas barrier performance: The solid-state battery was placed in a sealed cavity (25°C) and a mixed gas of 5% O2 and 100 ppm H2S was introduced in an argon atmosphere. After 48 hours, the residual concentration was detected by gas chromatograph and the gas adsorption rate was calculated.

[0104] 2. High temperature stability: Place the solid-state battery in a 200℃ oven for 2 hours and observe whether there are any problems such as cracking of the functional film;

[0105] 3. Cycle performance: The battery was charged and discharged at 0.33C rate at 60℃ (voltage range 2.5V-4.25V), and the capacity retention rate of the solid-state battery was recorded after 100 cycles.

[0106] 4. Humidity sensitivity: Store the battery in an environment with 85% humidity for 1 day and test the discharge capacity decay rate.

[0107] Table 1. Solid-state battery performance test results

[0108]

[0109]

[0110] In Table 1, "-" indicates that it was not tested.

[0111] As shown in Table 1, in Comparative Example 1, no functional membrane was used, and the solid-state battery had virtually no ability to adsorb oxygen and hydrogen sulfide gas. Its cycle capacity retention at 60°C was low, and it was highly sensitive to humidity. In Comparative Example 2, zinc oxide was used instead of sulfite. Zinc oxide is a hydrogen sulfide adsorbent and can perform physical adsorption, but the effect is limited. In Examples 1-5 and 7-8, a functional membrane containing sulfite, polymer, and water-absorbing oxide was placed between the solid-state cell and the encapsulation membrane. The sulfite in the functional membrane can adsorb oxygen and hydrogen sulfide gas, improving the safety and cycle performance of the solid-state battery. The functional membrane has high-temperature resistance and will not deform after being placed at 200°C for a period of time. The water-absorbing oxide has good hygroscopic properties, which can improve the cycle performance of the solid-state battery in high-humidity environments. In Example 6, a functional membrane containing sulfite and polymer was placed between the solid-state cell and the encapsulation membrane. This membrane can also adsorb oxygen and hydrogen sulfide gas, improving the safety, cycle performance, and high-temperature resistance of the solid-state battery.

[0112] In the description of this application, the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require this application to be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this application.

[0113] In the description of this specification, references to terms such as "one embodiment," "another embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. Additionally, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0114] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A solid-state battery, characterized in that, It includes a solid-state battery cell, a functional film, and an encapsulation film, wherein the functional film is located between the solid-state battery cell and the encapsulation film, and the functional film includes sulfite.

2. The solid-state battery according to claim 1, characterized in that, The sulfite includes one or more of sodium sulfite, potassium sulfite, and calcium sulfite.

3. The solid-state battery according to claim 1, characterized in that, The functional film covers at least a portion of the surface of the solid-state battery cell.

4. The solid-state battery according to claim 1, characterized in that, The sulfite has a D50 particle size of 20nm-200nm, and / or the sulfite has a specific surface area ≥35m². 2 / g.

5. The solid-state battery according to claim 1, characterized in that, The functional membrane also includes a polymer.

6. The solid-state battery according to claim 5, characterized in that, The functional membrane satisfies at least one of the following conditions: In the functional membrane, the mass ratio of sulfite to polymer is (50-85):(10-50); The melting temperature of the polymer is ≥200℃; The polymer includes one or more of polytetrafluoroethylene, polycarbonate, polyethylene terephthalate, polybenzimidazole, polyetheretherketone, and polyimide.

7. The solid-state battery according to claim 5, characterized in that, The functional membrane also includes water-absorbing oxides, which include one or more of Al2O3, CaO, MgO, BaO, SiO2, and CuSO4.

8. The solid-state battery according to claim 7, characterized in that, The mass percentage of water-absorbing oxides in the functional membrane is a, where 0 < a ≤ 10%.

9. The solid-state battery according to any one of claims 1-8, characterized in that, The thickness of the functional membrane is 8μm-25μm.

10. The solid-state battery according to any one of claims 1-8, characterized in that, The solid-state battery cell includes a positive electrode, an electrolyte layer, and a negative electrode. The electrolyte layer is located between the positive electrode and the negative electrode, and the electrolyte layer includes a sulfide electrolyte. And / or, the encapsulation film includes an aluminum-plastic film.

11. A method for preparing a solid-state battery according to any one of claims 1-10, characterized in that, include: The functional film is bonded to the solid-state battery cell, and an outer encapsulation film is covered with the outer layer. Vacuum encapsulation is then performed to obtain the solid-state battery. The functional membrane includes sulfite.

12. The method according to claim 11, characterized in that, The method for preparing the functional membrane includes: Sulfite, polymer, and solvent are mixed to obtain a slurry, which forms a functional membrane. Alternatively, sulfites, polymers, water-absorbing oxides, and solvents can be mixed to obtain a slurry, which forms a functional membrane.

13. An electrical appliance, characterized in that, Includes the solid-state battery according to any one of claims 1-10.

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