Solid-state battery and manufacturing method therefor, and electrical device

Abstract

The present disclosure provides a solid-state battery and a manufacturing method therefor, and an electrical device. The solid-state battery comprises a composite electrode sheet, a negative electrode sheet and an electrolyte; the composite electrode sheet comprises a positive electrode sheet and a solid-state electrolyte membrane, and the solid-state electrolyte membrane is arranged on at least one side of the positive electrode sheet; and the negative electrode sheet is arranged on the side of the solid-state electrolyte membrane distant from the positive electrode sheet, and the electrolyte is mainly arranged on the side of the composite electrode sheet. The solid-state battery has better electrochemical performance and safety performance.

Description

Solid-state battery, preparation method thereof, and power-using device Technical Field

[0001] The present disclosure relates to the field of battery manufacturing, and in particular to a solid-state battery and an electrical device. Background Art

[0002] Driven by the need for energy conservation and emission reduction, batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, market demand is also growing.

[0003] Lithium batteries are increasingly being used due to their high energy density, long charging life, and low self-discharge. Improving battery safety is a pressing technical issue in this field.

[0004] The approaches described in this section are not necessarily approaches that have been previously conceived or employed. Unless otherwise indicated, it should not be assumed that any approach described in this section is prior art simply by virtue of its inclusion in this section. Similarly, unless otherwise indicated, the issues raised in this section should not be considered as having been recognized in any prior art.

[0005] Summary of the Invention

[0006] The present disclosure provides a solid-state battery to improve the safety performance of the battery.

[0007] According to one aspect of the present disclosure, a solid-state battery is provided, which includes: a composite electrode sheet, a negative electrode sheet and an electrolyte, the composite electrode sheet includes a positive electrode sheet and a solid electrolyte membrane, the solid electrolyte membrane is arranged on at least one side of the positive electrode sheet; the negative electrode sheet is arranged on the side of the solid electrolyte membrane away from the positive electrode sheet, and the electrolyte is mainly arranged on the composite electrode sheet side.

[0008] According to another aspect of the present disclosure, a method for preparing a solid-state battery is provided, the method comprising: providing a composite electrode including a positive electrode and a solid electrolyte membrane; providing an electrolyte in the composite electrode to prepare an immersion electrode; and stacking the immersion electrode and the negative electrode to obtain a solid-state battery.

[0009] According to another aspect of the present disclosure, an electrical device is provided, which includes the above-mentioned solid-state battery or the solid-state battery prepared by the above-mentioned preparation method.

[0010] The beneficial technical effect of the present disclosure is that the solid-state battery reduces the probability of contact between the electrolyte and the negative electrode by mainly arranging the electrolyte on the side of the composite electrode, reduces the possibility of side reactions, and can effectively improve the electrochemical performance and safety of the battery.

[0011] These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Further details, features and advantages of the present disclosure are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:

[0013] FIG1 is a schematic diagram of a structure of a solid-state battery according to an exemplary embodiment;

[0014] FIG. 2 is a flowchart of a method of manufacturing a solid-state battery according to an exemplary embodiment. DETAILED DESCRIPTION

[0015] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0017] In the description of the embodiments of this application, the technical terms "first," "second," etc. are used only to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0018] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0019] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0020] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0021] It should be understood that in this specification, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships or dimensions based on the orientations or positional relationships or dimensions shown in the accompanying drawings, and these terms are used only for the convenience of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of this application.

[0022] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0023] A solid-state battery refers to a battery that uses a solid-state electrolyte to completely or partially replace the electrolyte. The use of solid-state electrolytes enables high-capacity, highly active negative electrode materials such as lithium metal to be used in secondary batteries. Therefore, solid-state batteries often have high energy density and safety performance. However, the overall electrical conductivity of solid-state electrolytes is relatively low, which makes the internal resistance of solid-state batteries relatively large and the overall rate performance relatively low. In order to compensate for this defect, a certain amount of liquid electrolyte is often retained in solid-state batteries. However, the contact between the liquid electrolyte and the negative electrode often produces more side reactions, reducing the electrochemical performance and safety performance of the battery.

[0024] In view of this, embodiments of the present disclosure provide a solid-state battery, a method for manufacturing the same, and an electrical device.

[0025] FIG. 1 is a structural diagram of a solid-state battery 100 according to an exemplary embodiment.

[0026] As shown in Figure 1, the solid-state battery 100 includes: a composite electrode sheet 110, a negative electrode sheet 120 and an electrolyte (not shown). The composite electrode sheet 110 includes a positive electrode sheet 111 and a solid electrolyte membrane 112. The solid electrolyte membrane 112 is arranged on at least one side of the positive electrode sheet 111, and the negative electrode sheet 120 is arranged on the side of the solid electrolyte membrane 112 away from the positive electrode sheet 111, as well as the electrolyte. The electrolyte is mainly arranged on the side of the composite electrode sheet 110.

[0027] In some embodiments, the solid electrolyte membrane 112 plays the role of active ion transport and electrochemical reaction connecting the positive electrode plate 111 and the negative electrode plate 120, and also plays the role of a battery separator to prevent direct contact between the positive electrode plate 111 and the negative electrode plate 120.

[0028] In some embodiments, the electrolyte is mainly disposed on the composite electrode 110 side, which means that the solvent in the electrolyte is mainly concentrated in the positive electrode 111 or the solid electrolyte membrane 112 or between the two.

[0029] This solid-state battery reduces the probability of contact between the electrolyte and the negative electrode by mainly placing the electrolyte on the composite electrode side, reduces the possibility of side reactions, and can effectively improve the electrochemical performance and safety of the battery.

[0030] In some embodiments, as shown in FIG1 , in the solid-state battery 110, the distance between any edge of the solid-state electrolyte membrane 112 and the central axis A of the solid-state battery is L1, the distance between any edge of the positive electrode plate 111 and the central axis A of the solid-state battery is L2, and the distance between any edge of the negative electrode plate 120 and the central axis A of the solid-state battery is L3, and L1>L3>L2.

[0031] The above settings can further improve the safety of solid-state batteries.

[0032] In some embodiments, the negative electrode plate includes lithium metal and its alloys.

[0033] Lithium metal negative electrode sheets are different from negative electrode sheets made of other materials (such as graphite, nitride, titanium-based materials, etc.) and have low density (lithium density is relatively low, only 0.534g / cm 3 The advantages of lithium metal and its alloys as negative electrode materials are high energy density and high capacity (the gram capacity of metallic lithium is as high as 3860 mA·h / g, ten times that of graphite negative electrodes). Therefore, the use of lithium metal and its alloys as negative electrode materials can significantly increase the energy density of batteries. In addition, the low electrochemical potential of lithium metal allows it to be used with a wider range of positive electrode materials (for example, positive electrode materials can contain lithium or not).

[0034] In some embodiments, the solid electrolyte membrane includes a base membrane and a first bonding portion disposed on the negative electrode tab side of the base membrane.

[0035] In some embodiments, the base film includes a solid electrolyte. In some embodiments, the first bonding portion includes a binder. In some embodiments, the first bonding portion includes a binder and a solid electrolyte. In some embodiments, the binder includes polyvinylidene fluoride or an acrylic polymer.

[0036] The first bonding portion can not only bond the solid electrolyte membrane and the negative electrode sheet, but also block the solvent in the electrolyte from infiltrating into the negative electrode sheet, so that the solid electrolyte membrane has a higher density and can reduce the diffusion of the solvent in the electrolyte to the negative electrode sheet.

[0037] In some embodiments, the solid electrolyte membrane further includes a second bonding portion disposed on the positive electrode tab side of the base membrane.

[0038] In some embodiments, the second bonding portion comprises a binder. In some embodiments, the second bonding portion comprises a binder and a solid electrolyte. In some embodiments, the second bonding portion is dispersed in a dot or strip pattern on the positive electrode sheet side of the base film. The second bonding portion facilitates the composite of the positive electrode sheet and the solid electrolyte membrane, improving the efficiency of composite sheet production.

[0039] In some embodiments, the second bonding portion is disposed at a side edge of the base film. This configuration achieves an encapsulation effect on the electrolyte and reduces electrolyte overflow.

[0040] The second bonding portion can not only bond the solid electrolyte membrane and the positive electrode sheet, but also effectively reduce the weight of the battery through reasonable design.

[0041] In some embodiments, the area coverage of the first bonding portion on the base film is greater than the area coverage of the second bonding portion on the base film.

[0042] In some embodiments, the area coverage of the first bonding portion on the base film is 70%-90% based on the total area of ​​the base film. In some embodiments, the area coverage of the first bonding portion on the base film can be 70%, 75%, 80%, 85%, 90%, or any range therebetween based on the total area of ​​the base film.

[0043] In some embodiments, the area coverage of the second bonding portion on the base film is 20%-30% based on the total area of ​​the base film. In some embodiments, the area coverage of the first bonding portion on the base film can be 20%, 25%, 30%, or any range therebetween based on the total area of ​​the base film.

[0044] The area coverage of the first bonding portion on the base film is a ratio of the projected area of ​​the first bonding portion on the base film divided by the area of ​​the base film.

[0045] In some embodiments, in the solid-state battery, the unit mass of the electrolyte is 0.1-2.5 g / Ah.

[0046] In some embodiments, in a solid-state battery, the unit mass of the electrolyte can be selected as 0.1 g / Ah, 0.5 g / Ah, 1 g / Ah, 1.5 g / Ah, 2 g / Ah, 2.5 g / Ah, or any range of values ​​therebetween.

[0047] In some embodiments, based on the total mass of the solid-state battery, the mass content of the electrolyte in the solid-state battery is less than or equal to 20%, optionally less than or equal to 10%, and optionally less than or equal to 5%.

[0048] In some embodiments, based on the total mass of the solid-state battery, the mass content of the electrolyte in the solid-state battery can be selected as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or any numerical range therebetween.

[0049] The inclusion of a small amount of electrolyte in solid-state batteries can effectively reduce the infiltration of solvents in the electrolyte into the negative electrode plate, so that the electrolyte is mainly concentrated on the composite electrode side, reducing the side reactions between the electrolyte and the negative electrode plate, and improving the electrochemical performance and safety of the battery.

[0050] In some embodiments, the solid electrolyte membrane includes a solid electrolyte including one or more of a polymer electrolyte, an oxide electrolyte, a sulfide electrolyte, and a halide electrolyte.

[0051] Polymer electrolytes include all-solid-state polymer electrolytes and gel polymer electrolytes. All-solid-state polymer electrolytes are obtained by dissolving lithium salts in a high-molecular-weight polymer matrix material. They are a type of complex formed by coordination between lithium salts and high-molecular-weight polymers. As the organic polymer segments in the amorphous region of the polymer matrix in the polymer electrolyte move, lithium ions continuously undergo "coordination-decoordination" with the electron-donating groups on the polymer matrix units, thereby enabling lithium ion migration. Gel polymer electrolytes are primarily composed of a polymer matrix, plasticizer, and lithium salt, which form a polymer network with a suitable microstructure through mutual dissolution.

[0052] In some embodiments, the polymer in the polymer electrolyte includes polyethylene oxide, polymethyl methacrylate, polyacrylonitrile, polyvinylidene fluoride-hexafluoropropylene copolymer, or polypropylene oxide. In some embodiments, the lithium salt in the polymer electrolyte includes one or more of LiClO4, LiPF6, LiCF3SO3, and LiN(CF3SO2)2.

[0053] In some embodiments, the sulfide electrolyte includes lithium sulfide. Sulfide electrolytes include but are not limited to Li2S-SiS2, Li2S-B2S3, Li2S-P2S5, etc.

[0054] In some embodiments, the oxide electrolyte includes lithium oxide, including but not limited to Li2O-B2O3-P2O5, Li2O-SEO2-B2O3, Li2O-B2O3-SiO2, etc.

[0055] In some embodiments, the positive electrode sheet includes a positive electrode active material, and the positive electrode active material includes one or more of lithium-containing phosphates and lithium transition metal oxides.

[0056] In some embodiments, the lithium transition metal oxide includes lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, and their respective doping or coating modified materials. The lithium-containing phosphate includes lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, and their respective doping or coating modified materials.

[0057] FIG. 2 is a schematic diagram of a method of manufacturing a solid-state battery according to an exemplary embodiment.

[0058] As shown in FIG2 , a method 200 for manufacturing a solid-state battery includes: step S210 , providing a composite electrode including a positive electrode and a solid electrolyte membrane; step S220 , providing an electrolyte in the composite electrode to prepare an immersed electrode; and step S230 , laminating the immersed electrode and the negative electrode to obtain a solid-state battery.

[0059] By first providing an electrolyte to a composite electrode sheet consisting of a positive electrode sheet and a solid electrolyte membrane, and then laminating it with the negative electrode sheet, the electrolyte is concentrated in the positive electrode sheet and the solid electrolyte membrane. A significant external force is required to force the solvent in the electrolyte through the solid electrolyte membrane and achieve direct contact with the negative electrode sheet. This preparation method can reduce the probability of direct contact between the solvent in the electrolyte and the negative electrode sheet, thereby improving the electrochemical performance and safety of the battery.

[0060] In some embodiments, step S210 specifically includes hot pressing the positive electrode sheet and the solid electrolyte membrane to prepare a composite electrode sheet.

[0061] In some embodiments, before step S230 , the method includes cutting the lithium metal material with at least one of a tool and a laser to obtain the negative electrode sheet.

[0062] It is understood that the cutter can be in any form, such as an alloy cutter, a contoured cutter die, etc. In the example, the cutter is set at the edge of the die to punch out the negative electrode sheet of a specified size and shape.

[0063] In some embodiments, the surface of the tool comprises ceramic or polymer.

[0064] It is understood that the ceramic or polymer can be provided on the surface of the tool in the form of a coating, or it can be directly integrally formed. The surface of the tool includes ceramic or polymer, and in particular, the above materials are provided on the surface of the blade, which can smoothly cut lithium metal materials, is less likely to cause tool sticking, and the incision cross-section is smoother, and the burrs on the cutting surface can be controlled at the micron level. In addition, since ceramic or polymer has good wear resistance, the service life of the cutting tool can be extended. In the example, the blade surface of the tool includes ceramic or polymer. In the example, the tool includes a metal blade body and a ceramic or polymer blade.

[0065] In some embodiments, the ceramic is selected from the group consisting of zirconium oxide, zinc oxide, titanium oxide, mica, magnesium oxide, silicon nitride, boron nitride, aluminum nitride, titanium nitride, and glass ceramics.

[0066] In some embodiments, the polymer comprises polytetrafluoroethylene.

[0067] In some embodiments, laser cutting is used to cut the lithium metal negative electrode sheet.

[0068] Since lithium metal is a silvery-white soft metal with the lowest density, contact cutting methods such as cutting tools are prone to physical problems such as lithium metal sticking to the knife and cutting adhesion. Laser cutting can effectively solve this problem. It uses a high-power density laser beam to irradiate the lithium metal material, quickly heating the lithium metal to its vaporization temperature, evaporating it to form holes. As the laser source moves relative to the lithium metal material, the holes are continuously formed into very narrow slits, such as about 0.1mm, completing high-quality cutting of the lithium metal material.

[0069] In some embodiments, the laser can be a red laser, a violet laser, or a green laser.

[0070] In some embodiments, the speed of laser cutting is 5 m / min to 100 m / min.

[0071] In some embodiments, the speed of laser cutting can be selected as 5m / min, 10m / min, 20m / min, 30m / min, 40m / min, 50m / min, 60m / min, 70m / min, 80m / min, 90m / min, 100m / min or any range therebetween.

[0072] The laser cutting speed within the above range can not only reduce cutting burrs, but also reduce the probability of lithium metal materials generating molten beads and deteriorating electrical performance during the heating and cooling process, thereby improving the molding quality of the negative electrode sheet.

[0073] In some embodiments, the preparation environment of the solid-state battery is an inert atmosphere or air with a dew point of -45°C to -90°C.

[0074] The inert atmosphere can be selected from one or more of nitrogen, argon, helium, and neon.

[0075] Dew point refers to the temperature to which the gaseous water contained in the air reaches saturation and condenses into liquid water under a fixed air pressure. In some embodiments, the dew point can be selected as -45°C, -50°C, -60°C, -70°C, -80°C, -90°C or any range of values ​​therebetween. It is understandable that the preparation of solid-state batteries can be carried out in a separate inert atmosphere or low dew point air environment, or in a mixed environment of inert atmosphere and low dew point air. Injecting the electrolyte and performing subsequent assembly in a low dew point environment or inert atmosphere can reduce the volatilization of solvents in the electrolyte and improve the stability of the battery's electrochemical performance.

[0076] A third aspect of the present application provides an electrical device, comprising a solid-state battery of any embodiment or a solid-state battery prepared by a preparation method of any embodiment.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A solid-state battery, characterized in that, The solid-state battery includes: a composite electrode, the composite electrode includes a positive electrode and a solid electrolyte membrane, and the solid electrolyte membrane is disposed on at least one side of the positive electrode; a negative electrode disposed on a side of the solid electrolyte membrane away from the positive electrode; and an electrolyte mainly disposed on the side of the composite electrode.

2. The solid-state battery according to claim 1, characterized in that, The negative electrode includes lithium metal and its alloys.

3. The solid-state battery according to claim 1, wherein The solid electrolyte membrane includes a base film and a first bonding portion disposed on the negative electrode side of the base film.

4. The solid-state battery according to claim 3, characterized in that, The solid electrolyte membrane further includes a second bonding portion disposed on the positive electrode side of the base film.

5. The solid-state battery according to claim 4, characterized in that, The area coverage rate of the first bonding portion on the base film is greater than the area coverage rate of the second bonding portion on the base film.

6. The solid-state battery according to claim 1, characterized in that, In the solid-state battery, the unit mass of the electrolyte is 0.1-2.5 g / Ah.

7. The solid-state battery according to claim 1, wherein The solid electrolyte membrane includes a solid electrolyte, and the solid electrolyte includes one or more of a polymer electrolyte, an oxide electrolyte, a sulfide electrolyte, and a halide electrolyte.

8. The solid-state battery according to claim 1, characterized in that, The positive electrode includes a positive active material, and the positive active material includes one or more of a lithium-containing phosphate and a lithium transition metal oxide.

9. A method for preparing a solid-state battery, characterized in that, The preparation method includes: providing a composite electrode including a positive electrode and a solid electrolyte membrane; providing an electrolyte in the composite electrode to prepare an impregnated electrode; stacking the impregnated electrode and the negative electrode to obtain a solid-state battery.

10. The preparation method according to claim 9, characterized in that, The preparation environment of the solid-state battery is an inert atmosphere or air with a dew point of -45°C to -90°C.

11. An electrical device, characterized in that, The electrical device includes the solid-state battery according to any one of claims 1 to 8 or the solid-state battery prepared by the preparation method according to claim 9 or 10.

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