Solid electrolyte, solid battery and energy storage device

Abstract

The invention relates to the technical field of batteries, in particular to a solid electrolyte, a solid-state battery and an energy storage device. The solid electrolyte includes: a substrate; the grid layer is arranged on the surface of at least one side of the substrate, the grid layer comprises a framework main body and a plurality of cavities separated by the framework main body, and the opening direction of at least one part of the cavities is configured to face a negative pole piece of the solid-state battery.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a solid electrolyte, a solid battery and an energy storage device. Background Art

[0002] Although solid-state batteries have more advantages than ion batteries in terms of safety, they have to face problems such as frequent changes in battery thickness during charging and discharging, which leads to accelerated battery capacity decay. How to effectively solve the above problems has become a difficult problem. Summary of the invention

[0003] In order to solve the above technical problems, the embodiments of the present application provide a solid electrolyte, a solid-state battery and an energy storage device to solve the frequent changes in thickness of the solid-state battery during the charging and discharging process and the series of problems it brings.

[0004] In a first aspect, an embodiment of the present application provides a solid electrolyte for use in a solid-state battery, wherein the solid electrolyte comprises:

[0005] substrate;

[0006] A grid layer, wherein the grid layer is disposed on at least one side surface of the substrate, the grid layer comprises a skeleton body and a plurality of chambers separated by the skeleton body, and at least a portion of the chambers are opened in a direction configured to face the negative electrode sheet of the solid-state battery.

[0007] Furthermore, the orthographic projection shape of the chamber toward the substrate includes at least one of a polygon, a circle, and an ellipse.

[0008] Preferably, the orthographic projection shape of the chamber toward the substrate includes a hexagon.

[0009] More preferably, the orthographic projection shape of the chamber toward the substrate includes a regular hexagon.

[0010] Furthermore, along a direction perpendicular to the thickness of the substrate, the cross-section of the chamber is trumpet-shaped, and the opening of the chamber expands outward in a direction away from the substrate.

[0011] Furthermore, the chamber has a middle area and an edge area located outside the middle area, and the chamber includes a plurality of first-type chambers located in the middle area and a plurality of second-type chambers located in the edge area, and the plurality of second-type chambers are more densely distributed than the plurality of first-type chambers.

[0012] Furthermore, the thickness of the mesh layer is 1 μm to 50 μm.

[0013] Furthermore, the substrate and the grid layer are an integrated structure.

[0014] Furthermore, the thickness of the mesh layer is 5 μm to 20 μm; and / or,

[0015] When the solid-state battery is in a charging state, the deposition thickness of the metal in the cavity of the mesh layer is 1% to 100% of the thickness of the mesh layer; and / or,

[0016] The substrate and the mesh layer are an integrated structure formed by powder die-casting; and / or,

[0017] The material of the substrate includes at least one of a sulfide electrolyte and a sulfide and polymer composite electrolyte; and / or,

[0018] The material of the grid layer includes at least one of a sulfide electrolyte and a sulfide and polymer composite electrolyte.

[0019] Furthermore, the solid electrolyte also includes a functional layer, which is arranged on the other side surface of the substrate away from the grid layer, and the functional layer is configured to be arranged toward the positive electrode plate of the solid-state battery, and the material of the functional layer includes an oxide electrolyte.

[0020] Furthermore, the oxide electrolyte comprises Li7La3Zr2O 12 、Na3Zr2Si2PO 12 , Li 0.33 La 0.56 TiO3 or Li 0.33 La 0.56 At least one of TiO3.

[0021] In a second aspect, an embodiment of the present application provides a solid-state battery, the solid-state battery comprising:

[0022] Positive electrode;

[0023] Negative electrode;

[0024] A solid electrolyte, wherein the solid electrolyte is disposed between the positive electrode sheet and the negative electrode sheet to form a battery core, and the solid electrolyte is the solid electrolyte as described in the first aspect;

[0025] Wherein, at least part of the grid layer is arranged between the substrate and the negative electrode plate.

[0026] Further, the negative electrode plate comprises: a negative electrode current collector, and a negative electrode active material layer provided on at least one side surface of the negative electrode current collector, wherein the negative electrode active material of the negative electrode active material layer comprises: at least one of an alkali metal, a carbon-based material, and a silicon-based material; and / or,

[0027] The solid-state battery is an alkali metal solid-state battery.

[0028] Furthermore, the positive electrode plate includes: a positive electrode current collector, and a positive electrode active material layer provided on at least one side surface of the positive electrode current collector, and the positive electrode active material of the positive electrode active material layer includes: a layered oxide containing an alkali metal element, a polyanion compound or a Prussian blue compound.

[0029] Further, the positive electrode active material layer includes the positive electrode active material having a unit cell volume change rate of ≤5%; and / or,

[0030] The positive electrode active material layer has a first region and a second region located outside the first region, wherein the surface density of the positive electrode active material in the first region is higher than the surface density of the positive electrode active material in the second region;

[0031] The chamber of the solid electrolyte has a middle region corresponding to the first region and an edge region corresponding to the second region. The chamber includes a plurality of first-type chambers located in the middle region and a plurality of second-type chambers located in the edge region. The plurality of second-type chambers are more densely distributed than the plurality of first-type chambers.

[0032] In a third aspect, an embodiment of the present application provides an energy storage device, which includes a solid-state battery as described in the second aspect.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The embodiment of the present application provides a solid electrolyte with a new structure, which not only has structural strength but can also utilize the structural characteristics of the grid layer to provide accommodation space for metal deposition, effectively suppressing frequent changes in electrode thickness during the charge and discharge process of the solid-state battery, thereby increasing the cycle life of the solid-state battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 is a schematic diagram of the cross-sectional structure of the solid electrolyte in the embodiment of the present application;

[0037] Figure 2 is a schematic diagram of the structure of the solid electrolyte in the embodiment of the present application;

[0038] Figure 3 is a schematic diagram of the structure of the solid electrolyte in an embodiment of the present application when viewed from above;

[0039] Figure 4 yes Figure 3 Other deformed structures of solid electrolytes;

[0040] Figure 5 is a schematic cross-sectional structure diagram of another solid electrolyte in an embodiment of the present application;

[0041] Figure 6 is a schematic diagram of the structure of another solid electrolyte in an embodiment of the present application when viewed from above;

[0042] Figure 7 is a schematic cross-sectional structure diagram of another solid electrolyte in an embodiment of the present application;

[0043] Figure 8 is a schematic cross-sectional structure diagram of a solid-state battery according to an embodiment of the present application;

[0044] Fig. 9 is a structural schematic diagram of a household energy storage system according to an embodiment of the present application;

[0045] Fig.10 It is a schematic diagram of the structure of the energy storage system of an embodiment of the present application.

[0046] Reference numerals:

[0047] 1. Solid electrolyte; 11. Substrate; 12. Grid layer; 121. Skeleton body; 122. Chamber; 122a. Middle area; 122b. Edge area; 1221. First type of chamber; 1222. Second type of chamber; 13. Functional layer; 2. Negative electrode plate; 3. Positive electrode plate; 100. Energy storage system; 10. Energy storage device; 20. Electric energy conversion device; 30. First user load; 40. Second user load; 50. High voltage cable; 60. First electric energy conversion device; 70. Second electric energy conversion device. DETAILED DESCRIPTION

[0048] In the present invention, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0049] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0050] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0052] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0053] Solid-state batteries have higher safety performance than ion batteries because they use solid electrolytes. However, solid electrolytes usually have high rigidity, which makes it more difficult for them to adapt to frequent changes in electrode thickness during charging and discharging. Taking alkali metal solid-state batteries as an example, the alkali metal components migrate back and forth between the positive and negative electrodes during battery charging and discharging, causing frequent changes in electrode thickness. The rigidity of the solid electrolyte limits its adaptability to such thickness changes, resulting in the accumulation of internal stress in the battery and poor contact between the electrode and electrolyte interface, which can easily lead to accelerated battery capacity decay.

[0054] It can be seen from this that although solid-state batteries have greater safety advantages, they need to face the challenges brought by changes in battery thickness during the charging and discharging process. It is necessary to overcome the problem of frequent changes in thickness of solid-state batteries through technological improvements.

[0055] Based on the above analysis, the embodiments of the present application provide a solid electrolyte, a solid-state battery and an energy storage device, which suppress the frequent thickness changes of the solid-state battery during the charging and discharging process by improving the structure of the solid-state electrolyte.

[0056] In a first aspect, the present application provides a solid electrolyte, combined with Figure 1 and Figure 2 As shown, Figure 1A schematic diagram of the cross-sectional structure of the solid electrolyte is shown (the cross-sectional direction is along the thickness direction of the solid electrolyte), Figure 2 1 is a schematic diagram of the structure of the solid electrolyte. The solid electrolyte 1 is used in a solid-state battery, and the solid-state electrolyte 1 includes a substrate 11 and a mesh layer 12. The mesh layer 12 is provided on at least one side surface of the substrate 11, and the mesh layer 12 includes a skeleton body 121 and a plurality of chambers 122 separated by the skeleton body 121, and the opening direction of at least a part of the chambers 122 is configured to be arranged toward the negative electrode sheet of the solid-state battery.

[0057] The embodiment of the present application provides a solid electrolyte 1 with a new structure, which, while having structural strength, can utilize the structural characteristics of the grid layer 12 to provide a space for metal deposition, effectively suppressing the frequent changes in the thickness of the negative electrode during the charge and discharge process of the solid-state battery, thereby improving the cycle life of the solid-state battery.

[0058] Among them, a grid layer 12 is arranged on at least one side surface of the substrate 11 of the solid electrolyte 1, that is, the grid layer 12 can be arranged on one side or both sides of the substrate 11. The opening direction of at least a part of the chambers 122 is configured to be arranged toward the negative electrode sheet of the solid-state battery, that is, the opening of a part of the chambers 122 can be toward the negative electrode sheet, and the opening of another part of the chambers 122 can be toward the positive electrode sheet, or the opening of all the chambers 122 can be toward the negative electrode sheet, thereby ensuring that at least a part of the space of the chambers 122 is used to accommodate the metal deposition on the negative electrode sheet side. Optionally, when the grid layer 12 is arranged on both sides, the grid layer 12 on either side can use the chamber 122 to provide a storage space; when it is arranged on one side, the grid layer 12 is arranged on one side of the substrate 11, and the other side can be arranged with a film layer with other functions, and the grid layer 12 is arranged on the side facing the negative electrode sheet, so that the solid electrolyte 1 can solve the problem of frequent changes in the thickness of the negative electrode through the chamber 122 of the grid layer 12, and can also provide more functions by setting a film layer with other functions. Since the thickness variation of solid-state batteries mainly comes from the deposition or stripping of metal on the negative electrode side, the grid layer 12 is preferably arranged on the side facing the negative electrode plate. This technical solution has a more significant effect in suppressing the frequent thickness variation of solid-state batteries.

[0059] Among them, the skeleton body 121 of the grid layer 12 can cooperate with the substrate 11 to provide a more stable structural support strength, and a plurality of chambers 122 separated by the skeleton body 121 can provide more accommodation space to accommodate the metal deposited on one side of the negative electrode plate during the charging and discharging process, so as to avoid these metals causing frequent changes in the thickness of the negative electrode and avoid poor interface contact between the solid electrolyte 1 and the negative electrode.

[0060] Specifically, the thickness of the solid-state battery changes frequently, mainly because of the deposition or stripping of the metal on the negative electrode side. When the solid electrolyte 1 is only a planar structure of the substrate 11, the contact between the substrate 11 and the negative electrode is a surface-to-surface contact, and there is no extra space between the two to accommodate the deposition or stripping of the metal, which will cause the thickness of the negative electrode and the battery to change frequently, thereby causing other problems. After the grid layer 12 is set on the substrate 11 in the embodiment of the present application, the chamber 122 of the grid layer 12 can accommodate the metal deposited on the negative electrode side during the charging process, thereby ensuring that the distance between the substrate 11 and the negative electrode remains unchanged or changes very little, thereby making the thickness of the solid-state battery remain unchanged or change very little during the charging and discharging process, effectively ensuring the cycle life of the solid-state battery.

[0061] In addition, although the solid electrolyte 1 is no longer a planar structure due to the presence of the grid layer 12, the solid electrolyte 1 has the characteristics of intrinsic electronic insulation, and there is no "tip discharge" effect, so it can ensure the deposition effect of the metal in the chamber 122 during the charging process. Specifically, in the initial deposition stage on the negative electrode side, the metal will preferentially deposit in the area in contact with the solid electrolyte 1, but then it will gradually deposit in the chamber 122 driven by the local pressure difference (specifically, the pressure in the chamber 122 is less than the pressure in the contact area between the negative electrode and the skeleton body 121), ensuring that the metal deposition effect in the chamber 122 is better. If a grid layer 12 similar to the present application is set on the negative current collector of the negative electrode, the above deposition effect cannot be achieved. The main reason is that if there is an uneven non-planar structure on the surface of the negative electrode collector, the deposition of metal on its surface will be affected by the "tip discharge" effect on the surface of the negative electrode collector, causing the metal to be deposited preferentially on the protruding parts, which will aggravate the dendrite problem. Secondly, after the metal grows to a certain stage, it may connect and close to each other on the surface of the grid layer 12, preventing subsequent metal from entering the chamber 122 for deposition, resulting in the setting of the chamber 122 not only failing to serve as a good accommodation space, but also causing other problems.

[0062] Alternatively, if Figure 3 and Figure 4 As shown, Figure 3 is a schematic diagram of the structure of the solid electrolyte 1 of the embodiment of the present application when viewed from above, Figure 4 yes Figure 3Other deformed structures of the solid electrolyte 1. The orthographic projection shape of the chamber 122 toward the substrate 11 includes at least one of a polygon, a circle, and an ellipse. Among them, the orthographic projection shape of the chamber 122 toward the substrate 11 is the projection shape observed from the direction of the chamber 122 toward the plane where the substrate 11 is located. Among them, a polygon is a plane figure composed of three or more line segments connected end to end in sequence. Exemplarily, the orthographic projection shape can be a rectangle, a square, a pentagon, a hexagon, a circle, an ellipse, etc., or a combination of different shapes. For example, the orthographic projection shape of several chambers 122 can be partly a rectangle and partly a hexagon, or partly a circle and partly an ellipse, and the present application does not limit this.

[0063] Preferably, the orthographic projection shape of the chamber 122 toward the substrate 11 includes a hexagon. When the solid-state battery is charged under a higher clamp pressure, the deposition process of the alkali metal on the negative electrode side is mainly a hexagonal growth process, so the orthographic projection shape of the chamber 122 adopts a hexagonal structure, which can better match the growth characteristics of the metal deposited on the negative electrode side. More preferably, the orthographic projection shape of the chamber 122 toward the substrate 11 includes a regular hexagon to further improve the degree of matching with the metal growth characteristics.

[0064] Furthermore, if Figure 5 As shown, Figure 5 It is a schematic diagram of the cross-sectional structure of another solid electrolyte 1 of an embodiment of the present application. Along the direction perpendicular to the thickness of the substrate 11, the cross-section of the chamber 122 is trumpet-shaped, and the opening of the chamber 122 expands outward in the direction away from the substrate 11. The chamber 122 adopts a trumpet-shaped structure with an opening expanding in the direction of the negative electrode sheet, which is beneficial to improve the degree of densification of the metal deposited in the chamber 122 during the charging process of the solid-state battery, ensuring that the chamber 122 can effectively accommodate more metal, and further ensuring that the distance between the substrate 11 and the negative electrode sheet remains unchanged or changes slightly. In addition, along the direction perpendicular to the thickness of the substrate 11, the cross-section of the chamber 122 can also be a shape with a uniform opening width, and can also be a shape with a gradually narrowing opening in the direction of the negative electrode sheet.

[0065] Furthermore, if Figure 6 As shown, Figure 6It is a schematic diagram of the structure of another solid electrolyte 1 in an embodiment of the present application when viewed from above. The chamber 122 has a middle area 122a and an edge area 122b located on the periphery of the middle area 122a. The chamber 122 includes a plurality of first-type chambers 1221 located in the middle area 122a and a plurality of second-type chambers 1222 located in the edge area 122b. The plurality of second-type chambers 1222 are more densely distributed than the plurality of first-type chambers 1221. The middle area 122a corresponds to the corresponding areas of the positive electrode sheet and the negative electrode sheet in the solid-state battery. The surface density of the positive active material in the corresponding area of ​​the positive electrode sheet is higher, so the amount of metal deposited on the negative electrode sheet side during the charging process of the solid-state battery is greater. Compared with the second type of chambers 1222 with relatively dense chambers 122, the first type of chambers 1221 located in the middle area 122a are more sparsely distributed and can accommodate a larger volume of the chamber 122 for metal deposition, so they can better meet the requirements of accommodating metals during the charging process, further reduce the impact of the charging and discharging process on the change in the thickness of the negative electrode, and better ensure the stability of the distance between the substrate 11 and the negative electrode sheet. In addition, the first type of chambers 1221 and the second type of chambers 1222 can also adopt the same or similar density.

[0066] Further, the thickness of the mesh layer 12 is 1 μm to 50 μm. Exemplarily, the thickness of the mesh layer 12 is 1 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm or 50 μm. Preferably, the thickness of the mesh layer 12 is 5 μm to 20 μm. The thickness of the mesh layer 12 is also the depth of the chamber 122. In addition, during the charging process of the solid-state battery, the deposition thickness of the metal in the chamber 122 of the mesh layer 12 is 1% to 100% of the thickness of the mesh layer 12, and the metal can be well accommodated in the chamber 122.

[0067] Furthermore, the substrate 11 and the grid layer 12 may be an integrated structure or independent separate structures, which are fixedly connected together by gluing or the like. Preferably, the substrate 11 and the grid layer 12 are an integrated structure, which makes the overall structural strength of the solid electrolyte 1 better. More preferably, the substrate 11 and the grid layer 12 are an integrated structure formed by powder die-casting. The integrated setting of the substrate 11 and the grid layer 12 is achieved by powder die-casting technology, and the corresponding die-casting mold can be designed according to the shape of the substrate 11 and the grid layer 12, which has the advantages of simple method and low cost. In addition, the overall density of the powder die-casting substrate 11 is high and the porosity is very low. This structural feature allows the metal on the negative electrode side to be deposited only in the cavity 122 of the grid layer 12 during the charging and discharging process of the solid-state battery, and will not easily penetrate into the dense substrate 11, ensuring that there is no risk of short circuit inside the solid-state battery.

[0068] In terms of materials, the substrate 11 and the grid layer 12 can be made of the same material or different materials. It is more convenient to make them into an integrated structure by using the same material, which is also conducive to keeping the properties of the two consistent. Therefore, it is preferred that the two use the same material. Optionally, the material of the substrate 11 includes at least one of a sulfide electrolyte and a sulfide and polymer composite electrolyte. Optionally, the material of the grid layer 12 includes at least one of a sulfide electrolyte and a sulfide and polymer composite electrolyte. Among them, the sulfide electrolyte includes Li 10 GeP2S 12 、Li7P3S 11 , Li6PS5Cl, etc. Sulfide-polymer composite electrolyte is a composite material obtained by combining sulfide electrolyte and polymer electrolyte, for example, a composite solid electrolyte 1 formed by adding sulfide electrolyte as filler to a polymer electrolyte as a matrix; the sulfide electrolyte is, for example, Li 10 GeP2S 12 、Li7P3S 11 , Li6PS5Cl, etc., and the polymer electrolyte is, for example, polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN) or polyvinyl chloride (PVC).

[0069] In addition to the above structure, combined Figure 7 As shown, the solid electrolyte 1 of the embodiment of the present application also includes a functional layer 13, which is arranged on the other side surface of the substrate 11 away from the grid layer 12, and the functional layer 13 is configured to be arranged toward the positive electrode sheet of the solid-state battery, and the material of the functional layer 13 includes an oxide electrolyte. That is to say, the substrate 11 has two surfaces arranged opposite to each other, one of which is provided with a grid layer 12, and the other surface is provided with a functional layer 13, and the grid layer 12 is configured to be arranged in the direction of the negative electrode sheet, and the functional layer 13 is configured to be arranged in the direction of the positive electrode sheet. Through the above-mentioned structural arrangement, the good compatibility of the oxide electrolyte with the positive active material can be utilized to suppress the interface side reaction between the positive electrode sheet and the solid electrolyte 1, so that the interface contact performance between the two is good. Therefore, through the cooperation of the grid layer 12 and the functional layer 13 on the two opposite sides of the substrate 11, it is ensured that the solid electrolyte 1 has good contact performance with both the positive electrode sheet and the negative electrode sheet.

[0070] Optionally, the oxide-based solid electrolyte 1 includes Li7La3Zr2O 12 、Na3Zr2Si2PO 12 , Li 0.33 La 0.56 TiO3 or Li 0.33 La 0.56 At least one of TiO3.

[0071] In a second aspect, the present application provides a solid-state battery. Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of a solid-state battery according to an embodiment of the present application, wherein the solid-state battery comprises: a positive electrode plate 3, a negative electrode plate 2 and a solid electrolyte 1, wherein the solid electrolyte 1 is arranged between the positive electrode plate 3 and the negative electrode plate 2 to form a battery cell, and the solid electrolyte 1 is the solid electrolyte 1 described in the first aspect; wherein at least a portion of the grid layer 12 is arranged between the substrate 11 and the negative electrode plate 2.

[0072] Since the thickness of the solid-state battery changes frequently mainly because of the deposition or stripping of metal on the negative electrode plate 2 side, a mesh layer 12 is provided between the substrate 11 and the negative electrode plate 2, so that the cavity 122 of the mesh layer 12 can be effectively used to accommodate the metal on the negative electrode plate 2 side, so that the metal during the charging process is deposited in the cavity 122, rather than adding an additional metal deposition layer on the negative electrode plate 2 side. In this way, the distance between the substrate 11 and the negative electrode plate 2 no longer changes frequently due to metal deposition during the charging and discharging process, which can avoid frequent changes in the thickness of the negative electrode and the battery, and ensure that the solid-state battery has a good cycle life.

[0073] Furthermore, the solid-state battery is an alkali metal solid-state battery, and the alkali metal solid-state battery includes a lithium metal solid-state battery, a sodium metal solid-state battery or a potassium metal solid-state battery.

[0074] The positive and negative electrode sheets 2 are introduced below.

[0075] The negative electrode plate 2 includes: a negative electrode current collector, and a negative electrode active material layer provided on at least one side surface of the negative electrode current collector, wherein the negative electrode active material of the negative electrode active material layer includes: at least one of alkali metals, carbon-based materials, and silicon-based materials.

[0076] The positive electrode sheet 3 includes: a positive electrode current collector, and a positive electrode active material layer disposed on at least one side of the positive electrode current collector, wherein the positive electrode active material of the positive electrode active material layer includes: a layered oxide containing an alkali metal element, a polyanion compound or a Prussian blue compound, wherein the alkali metal element includes lithium or sodium.

[0077] Optionally, the layered oxide is a layered transition metal oxide, wherein the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. Optionally, the layered transition metal oxide is, for example, Li x MO2, wherein M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, and 0<x≤1.

[0078] Alternatively, the polyanion compound may be a compound having metal ions, transition metal ions and tetrahedral (YO4) n- A class of compounds with anionic units. The metal ion can be selected from sodium ion, lithium ion, potassium ion, zinc ion; the transition metal can be selected from at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y can be selected from at least one of P, S and Si; n represents (YO4) n- valence state.

[0079] Optionally, the Prussian blue compound may be a compound having sodium ions, transition metal ions and cyanide ions (CN-). The transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. The Prussian blue compound may be, for example, Li a Me b Me' c (CN)6, wherein Me and Me' are each independently at least one of Ni, Cu, Fe, Mn, Co and Zn, 0<a≤2, 0<b<1, 0<c<1.

[0080] Preferably, the positive electrode active material layer includes a positive electrode active material with a unit cell volume change rate of ≤5%. The positive electrode active material with a unit cell volume change rate of ≤5% belongs to a material with small volume strain or zero strain, which can reduce the thickness change rate of the positive electrode plate 3 during the charge and discharge process, and then cooperate with the solid electrolyte 1 to further control the thickness of the solid-state battery to remain unchanged or change very little during the charge and discharge process, and ensure that the contact performance of the contact interface between the positive electrode plate 3 and the solid electrolyte 1 and the contact interface between the negative electrode plate 2 and the solid electrolyte 1 is good. Preferably, the positive electrode active material includes LiCoO2, whose unit cell volume change rate is less than 5%, which is conducive to further controlling the thickness change during the charge and discharge process of the solid-state battery.

[0081] Further, in the positive electrode sheet 3, the positive electrode active material layer has a first region and a second region located outside the first region, and the surface density of the positive electrode active material in the first region is higher than the surface density of the positive electrode active material in the second region. The first region is located in the middle of the positive electrode active material layer, and the second region is located at the edge of the positive electrode active material layer. Correspondingly, the grid layer 12 of the solid electrolyte 1 has a middle region 122a corresponding to the position of the first region and an edge region 122b corresponding to the position of the second region.

[0082] The surface density of the positive electrode active material in the first region is relatively higher, and correspondingly, the distribution of the first type of chambers 1221 in the middle region 122a is looser. As a result, the first type of chambers 1221 in the middle region 122a can accommodate a larger volume of metal deposition and can accommodate relatively more metal deposition. The surface density of the positive electrode active material in the second region is relatively lower, and correspondingly, the distribution of the second type of chambers 1222 in the edge region 122b is denser. As a result, although the second type of chambers 1222 in the edge region 122b can accommodate a smaller volume of metal deposition, it can also meet the requirements of accommodating metals with lower surface density and relatively less deposition in the first region.

[0083] In a third aspect, an embodiment of the present application provides an energy storage device, which includes a solid-state battery as described in the second aspect.

[0084] Taking electrochemical energy storage as an example, an embodiment of the present application provides an energy storage device 10, which has a group of chemical batteries in it. The chemical elements in the batteries are mainly used as energy storage media. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage media. In simple terms, the electricity generated by wind and solar energy is stored in chemical batteries. When the use of external electricity reaches a peak, the stored electricity is released for use, or transferred to places where electricity is scarce for use.

[0085] The current energy storage (i.e., energy storage) application scenarios are relatively wide, including energy storage on the power generation side, energy storage on the grid side, and energy storage on the power consumption side. The corresponding types of energy storage devices 10 include:

[0086] (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can help renewable energy generation meet grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive regulating power source on the power supply side, energy storage power stations can achieve load matching of electric energy in time and space, enhance the ability to absorb renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy generation, and are of great significance in power grid system backup, relieving peak load power supply pressure, and peak and frequency regulation.

[0087] (2) Energy storage containers used on the grid side mainly perform peak load regulation, frequency regulation, and grid congestion relief. They can achieve peak load shaving and valley filling of power loads, that is, charging the energy storage batteries when the power load is low and releasing the stored power during the peak load period, thereby achieving a balance between power production and consumption;

[0088] (3) Small energy storage cabinets used on the power consumption side, the main functions are self-generation and self-use of electricity, peak-valley price difference arbitrage, capacity cost management and improving power supply reliability. According to different application scenarios, energy storage on the power consumption side can be divided into industrial and commercial energy storage cabinets, household energy storage devices 10, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaics. Industrial and commercial users can use energy storage for valley-peak price difference arbitrage and capacity cost management. In the power market that implements peak-valley electricity prices, by charging the energy storage system 100 when the electricity price is low and discharging the energy storage system 100 when the electricity price is high, peak-valley electricity price difference arbitrage is achieved to reduce electricity costs. In addition, industrial enterprises that are subject to two-part electricity prices can use the energy storage system 100 to store energy during low electricity consumption and discharge it during peak load, thereby reducing peak power and the maximum demand reported, and achieving the purpose of reducing capacity electricity charges. Household photovoltaic storage can improve the level of self-generation and self-use of electricity. Due to high electricity prices and poor power supply stability, the demand for household photovoltaic installations is driven. Considering that photovoltaic power is generated during the day, and users generally have higher loads at night, energy storage can be configured to better utilize photovoltaic power, improve the level of self-generation and self-use, and reduce electricity costs. In addition, communication base stations, data centers and other fields need to configure energy storage for backup power.

[0089] See also Fig. 9 , Fig. 9 This is a structural diagram of a household energy storage system 100 of an embodiment of the present application. The present application provides a household energy storage system 100, which includes an electric energy conversion device 20 (photovoltaic panel), a first user load 30 (street lamp), a second user load 40 (such as air conditioners and other household appliances), and an energy storage device 10. The energy storage device 10 is a small energy storage box that can be mounted on an outdoor wall by wall hanging. Specifically, the photovoltaic panel can convert solar energy into electric energy during the period of low electricity prices. The energy storage device 10 is used to store the electric energy and supply it to street lamps and household appliances for use during peak electricity prices, or to supply power when the power grid is off / power outage.

[0090] See also Fig.10 , Fig.10 is a schematic diagram of the structure of an energy storage system 100 according to an embodiment of the present application, and the present application Fig.10 The embodiment is described by taking the shared energy storage scenario on the power generation / distribution side as an example, and the energy storage device 10 of the present application is not limited to the energy storage scenario on the power generation / distribution side.

[0091] The present application provides an energy storage system 100, which includes: a high-voltage cable 50, a first electric energy conversion device 60, a second electric energy conversion device 70 and an energy storage device 10 provided by the present application. In the case of power generation, the first electric energy conversion device 60 and the second electric energy conversion device 70 are used to convert other forms of energy into electric energy, connect with the high-voltage cable and supply it to the power distribution network for use. When the power load is low and the first electric energy conversion device 60 and the second electric energy conversion device 70 generate excess power, the excess power is stored in the energy storage device 10, reducing the wind and light abandonment rates and improving the problem of new energy power generation and consumption; when the power load is high, the power grid issues an instruction to use the power stored in the energy storage device 10 in conjunction with the high-voltage cable 50 to transmit the power to the power consumption side in a grid-connected mode, providing peak load regulation, frequency regulation, standby and other services for the operation of the power grid, giving full play to the peak load regulation of the power grid, promoting the peak load reduction and valley filling of the power grid, and alleviating the power supply pressure of the power grid.

[0092] Optionally, the first electric energy conversion device 60 and the second electric energy conversion device 70 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electric energy.

[0093] The number of energy storage devices 10 can be multiple, and multiple energy storage devices 10 are connected in series or in parallel. Multiple energy storage devices 10 are supported and electrically connected by isolation plates (not shown). In this embodiment, "multiple" refers to two or more. An energy storage box can also be provided outside the energy storage device 10 to accommodate the energy storage device 10.

[0094] Optionally, the energy storage device 10 may include but is not limited to a battery module, a battery pack, a battery system, etc. The actual application form of the energy storage device 10 provided in the embodiment of the present application may be but is not limited to the listed products, and may also be other application forms. The embodiment of the present application does not strictly limit the application form of the energy storage device 10. The embodiment of the present application only takes the energy storage device 10 as a multi-core battery as an example for explanation. When the energy storage device 10 is a single battery, the energy storage device 10 may be at least one of a cylindrical battery, a square battery, etc.

[0095] The solution of the present application will be further introduced below in conjunction with specific embodiments and experimental data.

[0096] Example 1

[0097] This embodiment provides a solid-state battery, which is prepared by the following method.

[0098] Preparation of positive electrode sheet: The positive electrode active material NCM811, the conductive agent Ketjen black, and the binder PVDF are mixed in a stirring device at a mass ratio of 80:10:10, and then the solvent nitrogen methyl pyrrolidone is added and stirred to form a uniform positive electrode slurry, and the solid content of the positive electrode slurry is 40%; the positive electrode slurry is coated on the aluminum foil positive electrode collector, dried, and cold pressed to obtain a positive electrode sheet, and the area specific capacity of the positive electrode active material is controlled to be 2mAh / cm 2 .

[0099] Negative electrode: metallic lithium sheet.

[0100] Solid electrolyte: In an inert atmosphere, Li 10 GeP2S 12 After the powder is filled into the die-casting mold, it is die-casted at a pressure of 100 MPa for 1 minute to form an integrally formed substrate and grid layer to obtain a solid electrolyte; wherein the grid layer is located on one side surface of the substrate, and the grid layer includes a skeleton body and a plurality of chambers separated by the skeleton body.

[0101] Assembling a full battery: stack the positive electrode sheet, solid electrolyte, and negative electrode sheet in order, with the solid electrolyte located between the positive and negative electrodes, to assemble a full battery.

[0102] Embodiment 2 to Embodiment 4

[0103] The difference from Example 1 is that the thickness of the mesh layer is different.

[0104] Example 5

[0105] The difference from Example 3 is that the orthographic projection shape of the chamber in the grid layer toward the substrate is different.

[0106] Example 6

[0107] The difference from Example 3 is that the cross-sectional shape of the chamber in the grid layer is different along the direction perpendicular to the thickness of the substrate.

[0108] Embodiment 7 to Embodiment 9

[0109] The difference from Example 3 is that the solid electrolyte also includes a functional layer arranged on the other side surface of the substrate, and its preparation method includes: after pressing into an integrally formed substrate and a grid layer, evenly sprinkling oxide electrolyte powder on the other side surface of the substrate, and then die-casting at 900 MPa for 5 minutes to obtain a solid electrolyte with a grid layer on one side surface of the substrate and a functional layer on the other side surface.

[0110] Example 10 to Example 11

[0111] The difference from Example 9 is that the positive electrode active material is different.

[0112] Comparative Example 1

[0113] The difference from Example 1 is that the solid electrolyte only includes a substrate, and no grid layer is provided.

[0114] <Performance Test>

[0115] (1) Positive electrode sheet or negative electrode sheet thickness change rate test

[0116] After the battery is assembled, charge the battery to the set upper limit voltage (3.5V at 1000mA) on the charge and discharge tester, disassemble the battery in the glove box and measure the thickness T of the positive electrode or negative electrode. 充 Then, the same type of battery was discharged at a constant current to the set lower limit voltage (discharged at a constant current to 1.5V under 1000mA), and then the battery was disassembled in the glove box and the thickness T of the positive electrode sheet or the negative electrode sheet was measured. 放 . Specify T 放 As the reference thickness of the positive electrode sheet or the negative electrode sheet, (T 充 -T 放 ) / T 放 The absolute value is the thickness change rate of the positive electrode sheet or the negative electrode sheet.

[0117] (2) Cycle capacity retention test

[0118] After the battery is assembled, a constant current charge and discharge test is performed on the battery on a charge and discharge tester; the test temperature is 25°C, the cycle rate is 1C (i.e., both the charge rate and the discharge rate are 1C), the charging voltage is 1.5V to 3.5V, and the capacity retention rate after 100 cycles is calculated; the ratio of the battery's 100th cycle discharge capacity / 1st cycle discharge capacity is the cycle capacity retention rate after 100 cycles.

[0119] Table 1 Solid-state battery setting parameters and performance test results of the embodiment and comparative example

[0120]

[0121] Note: 1. “ / ” in Table 1 means there is no relevant parameter.

[0122] 2. LLZO in Table 1 refers to Li7La3Zr2O 12 , LATPO refers to Li 1.3 Al 0.3 Ti 1.7 (PO4)3, LLTO refers to Li 0.33 La 0.56 TiO3, NCM811 refers to LiNi 0.8 Co 0.1 Mn 0.1O2, NCM523 refers to LiNi 0.5 Co 0.2 Mn 0.3 O2.

[0123] Comparing Comparative Example 1 with each embodiment, it can be seen that the solid electrolyte of Comparative Example 1 only uses a substrate, that is, a conventional planar solid electrolyte, and the battery using this solid electrolyte has the highest negative electrode thickness change rate during charge and discharge, and the lowest cycle capacity retention rate. The solid electrolyte of each embodiment includes a substrate and a grid layer, and the negative electrode thickness change rate during charge and discharge is significantly reduced, and the cycle capacity retention rate based on this is also improved to a certain extent.

[0124] Comparing Examples 1 to 4, it can be seen that increasing the thickness of the solid electrolyte grid layer can reduce the rate of change of the negative electrode thickness and improve the cycle capacity retention rate. However, as the thickness of the grid layer in the solid electrolyte increases to a certain extent, the cycle capacity retention rate of the solid-state battery no longer continues to increase. This is because after the total volume of the grid layer chamber exceeds the volume required for depositing alkali metals on the negative electrode side, continuing to increase the thickness of the grid layer can no longer continue to reduce the rate of change of the negative electrode thickness. Instead, it will cause the density of the deposited alkali metal to decrease, and the side reactions will increase, which will affect the cycle capacity retention rate and no longer continue to increase.

[0125] By comparing Example 3, Example 5 to Example 6, it can be seen that adjusting the shape of the solid electrolyte grid layer chamber has a certain effect on the negative electrode thickness change rate and the cycle capacity retention rate. Preferably, when the shape of the chamber's positive projection changes from a rectangle to a hexagon, it can better match the growth characteristics of the metal deposited on the negative electrode side, the density of the deposited alkali metal increases, the negative electrode thickness change rate decreases, and the cycle capacity retention rate increases. Preferably, when the chamber cross-sectional shape changes from a rectangle to a trumpet shape, it is beneficial to increase the degree of densification of the metal deposited in the chamber during the solid-state battery charging process, the negative electrode thickness change rate decreases, and the cycle capacity retention rate increases.

[0126] Comparing Example 3, Example 7 to Example 9, it can be seen that when the functional layer is arranged on the other side of the solid electrolyte substrate, it is beneficial to improve the battery cycle capacity retention rate. Through the above-mentioned structural arrangement, the good compatibility of the oxide electrolyte with the positive electrode active material can be utilized to suppress the interface side reaction between the positive electrode plate and the solid electrolyte, so that the interface contact performance between the two is good. Preferably, when the functional layer adopts LATPO, the battery cycle performance is better.

[0127] Comparing Examples 9 to 11, it can be seen that adjusting the type of positive electrode active material has a certain influence on the positive electrode thickness change rate and the battery cycle capacity retention rate. When the positive electrode unit cell volume change rate decreases, the positive electrode thickness change rate decreases during charge and discharge, the contact performance of the positive electrode-solid electrolyte interface becomes better, and the battery cycle capacity retention rate increases. Preferably, when LiCoO2 is selected as the positive electrode active material, the overall performance of the battery is better.

[0128] The technical solutions disclosed in the embodiments of the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A solid electrolyte for use in a solid-state battery, characterized in that: The solid electrolyte comprises: substrate; A grid layer, wherein the grid layer is disposed on at least one side surface of the substrate, the grid layer comprises a skeleton body and a plurality of chambers separated by the skeleton body, and at least a portion of the chambers are opened in a direction configured to face the negative electrode sheet of the solid-state battery.

2. The solid electrolyte according to claim 1, characterized in that The orthographic projection shape of the chamber toward the substrate includes at least one of a polygon, a circle, and an ellipse.

3. The solid electrolyte according to claim 2, characterized in that The orthographic projection shape of the chamber toward the substrate includes a hexagon.

4. The solid electrolyte according to claim 1, characterized in that Along a direction perpendicular to the thickness of the substrate, the cross section of the chamber is trumpet-shaped, and the opening of the chamber expands outwards in a direction away from the substrate.

5. The solid electrolyte according to claim 1, characterized in that The chamber has a middle area and an edge area located at the periphery of the middle area. The chamber includes a plurality of first-type chambers located in the middle area and a plurality of second-type chambers located in the edge area. The plurality of second-type chambers are more densely distributed than the plurality of first-type chambers.

6. The solid electrolyte according to claim 1, characterized in that The thickness of the grid layer is 1 μm to 50 μm.

7. The solid electrolyte according to claim 1, characterized in that The substrate and the grid layer are an integrated structure.

8. The solid electrolyte according to claim 1, characterized in that The thickness of the mesh layer is 5 μm to 20 μm; and / or, When the solid-state battery is in a charging state, the deposition thickness of the metal in the cavity of the mesh layer is 1% to 100% of the thickness of the mesh layer; and / or, The substrate and the mesh layer are an integrated structure formed by powder die-casting; and / or, The material of the substrate includes at least one of a sulfide electrolyte and a sulfide and polymer composite electrolyte; and / or, The material of the grid layer includes at least one of a sulfide electrolyte and a sulfide and polymer composite electrolyte.

9. The solid electrolyte according to any one of claims 1 to 8, characterized in that The solid electrolyte also includes a functional layer, which is arranged on the other side surface of the substrate away from the grid layer. The functional layer is configured to be arranged toward the positive electrode plate of the solid-state battery, and the material of the functional layer includes an oxide electrolyte.

10. The solid electrolyte according to claim 9, characterized in that The oxide electrolyte includes Li7La3Zr2O 12 、Na3Zr2Si2PO 12 , Li 0.33 La 0.56 TiO3 or Li 0.33 La 0.56 At least one of TiO3.

11. A solid-state battery, characterized in that: The solid-state battery comprises: Positive electrode; Negative electrode; A solid electrolyte, wherein the solid electrolyte is disposed between the positive electrode sheet and the negative electrode sheet to form a battery core, and the solid electrolyte is the solid electrolyte according to any one of claims 1 to 10; Wherein, at least part of the grid layer is arranged between the substrate and the negative electrode plate.

12. The solid-state battery according to claim 11, characterized in that: The negative electrode plate comprises: a negative electrode current collector, and a negative electrode active material layer provided on at least one side surface of the negative electrode current collector, wherein the negative electrode active material of the negative electrode active material layer comprises: at least one of an alkali metal, a carbon-based material, and a silicon-based material; and / or, The solid-state battery is an alkali metal solid-state battery.

13. The solid-state battery according to claim 11, characterized in that: The positive electrode plate comprises: a positive electrode current collector, and a positive electrode active material layer disposed on at least one side of the positive electrode current collector. The positive electrode active material of the positive electrode active material layer comprises: a layered oxide containing alkali metal elements, a polyanion compound or a Prussian blue compound.

14. The solid-state battery according to claim 13, characterized in that: The positive electrode active material layer includes the positive electrode active material having a unit cell volume change rate of ≤5%; and / or, The positive electrode active material layer has a first region and a second region located outside the first region, wherein the surface density of the positive electrode active material in the first region is higher than the surface density of the positive electrode active material in the second region; The chamber of the solid electrolyte has a middle region corresponding to the first region and an edge region corresponding to the second region. The chamber includes a plurality of first-type chambers located in the middle region and a plurality of second-type chambers located in the edge region. The plurality of second-type chambers are more densely distributed than the plurality of first-type chambers.

15. An energy storage device, characterized in that: The energy storage device comprises a solid-state battery as described in any one of claims 11 to 14.

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