Solid-state electrolyte, solid-state battery, and energy storage device

Abstract

The present application relates to the technical field of batteries, and in particular, to a solid-state electrolyte, a solid-state battery, and an energy storage device. The solid-state electrolyte comprises: a substrate and a grid layer 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, wherein openings of at least some of the chambers are oriented towards a negative electrode sheet of the solid-state battery.

Description

Solid electrolytes, solid batteries and energy storage devices

[0001] Related cross-references

[0002] This application claims priority to Chinese Patent Application No. 2024118643837, filed on December 17, 2024, entitled "Solid Electrolyte, Solid Battery and Energy Storage Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and in particular to a solid electrolyte, a solid battery, and an energy storage device. Background Technology

[0004] While solid-state batteries have advantages over lithium-ion batteries in terms of safety, they also face challenges such as frequent changes in battery thickness during charging and discharging, which leads to accelerated capacity decay. Effectively addressing these issues remains a challenge. Summary of the Invention

[0005] To address the aforementioned technical problems, embodiments of this application provide a solid electrolyte, a solid battery, and an energy storage device to solve the problems caused by the frequent changes in the thickness of solid batteries during charging and discharging.

[0006] In a first aspect, embodiments of this application provide a solid electrolyte for use in a solid-state battery, the solid electrolyte comprising:

[0007] Base;

[0008] A mesh layer is disposed on at least one side surface of the substrate. The mesh layer includes a skeleton body and a plurality of chambers separated by the skeleton body. At least a portion of the chambers have their openings configured to face the negative electrode of the solid-state battery.

[0009] Secondly, embodiments of this application provide a solid-state battery, the solid-state battery comprising:

[0010] Positive electrode sheet;

[0011] Negative electrode sheet;

[0012] A solid electrolyte, wherein the solid electrolyte is disposed between the positive electrode and the negative electrode to form a battery cell, and the solid electrolyte is as described in the first aspect;

[0013] At least a portion of the mesh layer is disposed between the substrate and the negative electrode sheet.

[0014] Thirdly, embodiments of this application provide an energy storage device, which includes a solid-state battery as described in the second aspect.

[0015] Compared with the prior art, the beneficial effects of this application are as follows:

[0016] This application provides a novel solid electrolyte structure that, while possessing structural strength, utilizes the structural characteristics of the grid layer to provide space for metal deposition, effectively suppressing frequent changes in electrode thickness during the charging and discharging process of the solid battery, thereby improving the cycle life of the solid battery. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 is a schematic cross-sectional view of the solid electrolyte in an embodiment of this application;

[0019] Figure 2 is a schematic diagram of the solid electrolyte structure in an embodiment of this application;

[0020] Figure 3 is a schematic diagram of the solid electrolyte of an embodiment of this application from a bottom-view perspective;

[0021] Figure 4 shows other modified structures of the solid electrolyte in Figure 3;

[0022] Figure 5 is a cross-sectional structural diagram of another solid electrolyte according to an embodiment of this application;

[0023] Figure 6 is a schematic diagram of the structure of another solid electrolyte according to an embodiment of this application from a bottom-view perspective;

[0024] Figure 7 is a cross-sectional structural diagram of another solid electrolyte according to an embodiment of this application;

[0025] Figure 8 is a cross-sectional structural diagram of a solid-state battery according to an embodiment of this application;

[0026] Figure 9 is a structural schematic diagram of a residential energy storage system according to an embodiment of this application;

[0027] Figure 10 is a schematic diagram of the energy storage system according to an embodiment of this application.

[0028] Reference numerals: 1. Solid electrolyte; 11. Substrate; 12. Mesh layer; 121. Main skeleton; 122. Chamber; 122a. Intermediate region; 122b. Edge region; 1221. First type of chamber; 1222. Second type of chamber; 13. Functional layer; 2. Negative electrode; 3. Positive electrode; 100. Energy storage system; 10. Energy storage device; 20. Power conversion device; 30. First user load; 40. Second user load; 50. High-voltage cable; 60. First power conversion device; 70. Second power conversion device. Detailed Implementation

[0029] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0030] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0031] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0032] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0033] The technical solution of this application will be further described below with reference to the embodiments.

[0034] Solid-state batteries offer higher safety performance compared to lithium-ion batteries due to their use of solid electrolytes. However, solid electrolytes typically exhibit high rigidity, making them more susceptible to adapting to frequent changes in electrode thickness during charging and discharging. For example, in alkali metal solid-state batteries, the migration of alkali metal components between the positive and negative electrodes during charging and discharging causes frequent changes in electrode thickness. The rigidity of the solid electrolyte limits its adaptability to these thickness variations, leading to the accumulation of internal stress and poor contact between the electrodes and electrolyte, thus resulting in accelerated capacity decay.

[0035] Therefore, although solid-state batteries have a greater safety advantage, they still face the challenge of thickness changes during charging and discharging. It is necessary to overcome the problem of frequent thickness changes in solid-state batteries through technological improvements.

[0036] Based on the above analysis, this application provides a solid electrolyte, a solid battery, and an energy storage device. By improving the structure of the solid electrolyte, the degree of frequent thickness changes of the solid battery during charging and discharging is suppressed.

[0037] In a first aspect, embodiments of this application provide a solid electrolyte. Referring to Figures 1 and 2, Figure 1 shows a cross-sectional view of the solid electrolyte (the cross-section is taken along the thickness direction of the solid electrolyte), and Figure 2 is a structural schematic diagram of the solid electrolyte. This solid electrolyte 1 is used in a solid-state battery. The solid electrolyte 1 includes a substrate 11 and a mesh layer 12. The mesh layer 12 is disposed on at least one surface of the substrate 11. The mesh layer 12 includes a framework body 121 and a plurality of chambers 122 separated by the framework body 121. The opening direction of at least a portion of the chambers 122 is configured to face the negative electrode of the solid-state battery.

[0038] This application provides a novel solid electrolyte 1, which, while possessing structural strength, utilizes the structural characteristics of the grid layer 12 to provide space for metal deposition, effectively suppressing frequent changes in the negative electrode thickness during the charging and discharging process of the solid battery, thereby improving the cycle life of the solid battery.

[0039] A grid layer 12 is disposed on at least one surface of the substrate 11 of the solid electrolyte 1, meaning the grid layer 12 can be disposed on one or both sides of the substrate 11. At least a portion of the openings of the chambers 122 are configured to face the negative electrode of the solid-state battery; that is, some chambers 122 may have their openings facing the negative electrode and others facing the positive electrode, or all chambers 122 may have their openings facing the negative electrode, thus ensuring that at least a portion of the space in the chambers 122 is used to accommodate metal deposition on the negative electrode side. Optionally, when the grid layer 12 is disposed on both sides, the grid layer 12 on either side can utilize the chambers 122 to provide accommodating space; when disposed on one side, the grid layer 12 is disposed on one side of the substrate 11, and a film layer with other functions can be disposed on the other side, with the grid layer 12 disposed on the side facing the negative electrode. This allows the solid electrolyte 1 to address the problem of frequent changes in negative electrode thickness through the chambers 122 of the grid layer 12, and also to provide more functions through the 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, it is preferable to set the mesh layer 12 on the side facing the negative electrode sheet. This technical solution has a more significant effect on suppressing frequent thickness variations of solid-state batteries.

[0040] The skeleton body 121 of the grid layer 12 can cooperate with the substrate 11 to provide more stable structural support strength. The several chambers 122 formed by the skeleton body 121 provide more space to accommodate the metal deposited on one side of the negative electrode during charging and discharging, so as to avoid the metal causing frequent changes in the thickness of the negative electrode and to avoid poor interface contact between the solid electrolyte 1 and the negative electrode.

[0041] Specifically, the frequent changes in the thickness of solid-state batteries are mainly due to the deposition or stripping of 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, with no extra space between them to accommodate metal deposition or stripping. This leads to frequent changes in the thickness of the negative electrode and the battery, which in turn causes other problems. In this embodiment, after a mesh layer 12 is provided on the substrate 11, the chambers 122 of the mesh layer 12 can accommodate the metal deposited on the negative electrode side during charging, thereby ensuring that the distance between the substrate 11 and the negative electrode remains constant or changes very little. Consequently, the thickness of the solid-state battery remains constant or changes very little during charging and discharging, effectively guaranteeing the cycle life of the solid-state battery.

[0042] Furthermore, although the solid electrolyte 1 is no longer a planar structure due to the presence of the grid layer 12, the solid electrolyte 1 possesses intrinsic electronic insulation properties and does not exhibit a "point discharge" effect. Therefore, it can ensure the effective deposition of metal in the chamber 122 during charging. Specifically, during the initial deposition stage on the negative electrode side, metal preferentially deposits in the area in contact with the solid electrolyte 1. However, subsequently, driven by local pressure differences (specifically, the pressure in the chamber 122 is lower than the pressure in the contact area between the negative electrode and the main body 121), it gradually deposits into the chamber 122, ensuring a good metal deposition effect within the chamber 122. If a grid layer 12 similar to that of this application is provided on the negative current collector of the negative electrode, the above-mentioned deposition effect cannot be achieved. The main reason is that if the surface of the negative electrode current collector has an uneven, non-planar structure, the deposition of metal on its surface will be affected by the "point discharge" effect on the surface of the negative electrode current collector, causing the metal to preferentially deposit on the protruding parts. This will exacerbate the dendrite problem. Secondly, after the metal grows to a certain stage, it may connect and close with each other on the surface of the grid layer 12, preventing subsequent metal from entering the chamber 122 for deposition. As a result, the setting of the chamber 122 not only fails to play a good role in containing space, but also brings other problems.

[0043] Optionally, as shown in Figures 3 and 4, Figure 3 is a structural schematic diagram of the solid electrolyte 1 in an embodiment of this application from a bottom view, and Figure 4 shows other modified structures of the solid electrolyte 1 in Figure 3. The orthographic projection shape of the chamber 122 toward the substrate 11 includes at least one of polygons, circles, and ellipses. The orthographic projection shape of the chamber 122 toward the substrate 11 is the projection shape viewed from the plane containing the chamber 122 toward the substrate 11. A polygon is a planar figure composed of three or more line segments connected end-to-end. 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 rectangular and partly hexagonal, or partly circular and partly elliptical; this application does not limit this.

[0044] Preferably, the orthographic projection shape of the chamber 122 toward the substrate 11 is hexagonal. When the solid-state battery is charged under high clamping pressure, the alkali metal deposition process on the negative electrode side is dominated by hexagonal growth. Therefore, the orthographic projection shape of the chamber 122 adopts a hexagonal structure, which can better match the growth characteristics of metal deposition on the negative electrode side. More preferably, the orthographic projection shape of the chamber 122 toward the substrate 11 is a regular hexagon to further improve the matching degree with the metal growth characteristics.

[0045] Further, as shown in Figure 5, which is a cross-sectional structural schematic diagram of another solid electrolyte 1 according to an embodiment of this application, the cross-section of the chamber 122 is trumpet-shaped along the direction perpendicular to the thickness of the substrate 11, and the opening of the chamber 122 expands outward in the direction away from the substrate 11. The trumpet-shaped structure of the chamber 122 with an opening that expands towards the negative electrode plate is beneficial for improving the density of metal deposition within the chamber 122 during solid-state battery charging, ensuring that the chamber 122 can effectively accommodate more metal, and further ensuring that the distance between the substrate 11 and the negative electrode plate remains constant or changes only 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, or it can be a shape with the opening gradually narrowing towards the negative electrode plate.

[0046] Further, as shown in Figure 6, which is a structural schematic diagram of another solid electrolyte 1 according to an embodiment of this application from a bottom view, the chamber 122 has a central region 122a and an edge region 122b located on the outer periphery of the central region 122a. The chamber 122 includes a plurality of first-type chambers 1221 located in the central region 122a and a plurality of second-type chambers 1222 located in the edge region 122b. The plurality of second-type chambers 1222 are more densely distributed than the plurality of first-type chambers 1221. The central region 122a corresponds to the corresponding regions of the positive electrode and the negative electrode in the solid-state battery. The areal density of the positive active material is higher in the corresponding region of the positive electrode, so more metal is deposited on the negative electrode side during the charging process of the solid-state battery. Compared to the relatively dense second-type chambers 1222 in the intermediate region 122a, the first-type chambers 1221 are more loosely distributed and have a larger volume to accommodate metal deposition. This better accommodates the metal during charging, further reducing the impact of charging and discharging on the thickness change of the negative electrode and better ensuring the stability of the distance between the substrate 11 and the negative electrode sheet. Furthermore, the first-type chambers 1221 and the second-type chambers 1222 can also have the same or similar density.

[0047] 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. Furthermore, during solid-state battery charging, the metal deposition thickness in the chamber 122 of the mesh layer 12 is 1% to 100% of the thickness of the mesh layer 12, allowing the metal to be well contained within the chamber 122.

[0048] Furthermore, the substrate 11 and the grid layer 12 can be either an integrated structure or separate independent structures, fixedly connected together by adhesives or other means. Preferably, the substrate 11 and the grid layer 12 are an integrated structure, which results in better overall structural strength of the solid electrolyte 1. More preferably, the substrate 11 and the grid layer 12 are an integrated structure formed by powder die casting. Achieving the integrated configuration of the substrate 11 and the grid layer 12 through powder die casting technology allows for the design of corresponding die casting molds based on the shapes of the substrate 11 and the grid layer 12, offering advantages such as simplicity and low cost. In addition, the powder-die-cast substrate 11 has high overall density and very low porosity. This structural characteristic ensures that during the charging and discharging process of the solid-state battery, the metal on the negative electrode side is deposited only in the chamber 122 of the grid layer 12, and does not easily penetrate into the dense substrate 11, ensuring no short-circuit risk inside the solid-state battery.

[0049] Regarding materials, the substrate 11 and the mesh layer 12 can be made of the same material or different materials. Using the same material makes it easier to fabricate an integrated structure and also helps to maintain consistent properties; therefore, it is preferred that they be made of the same material. Optionally, the material of the substrate 11 includes at least one of a sulfide electrolyte and a sulfide-polymer composite electrolyte. Optionally, the material of the mesh layer 12 includes at least one of a sulfide electrolyte and a sulfide-polymer composite electrolyte. The sulfide electrolyte includes Li... 10 GeP2S 12 Li7P3S 11 Li6PS5Cl, etc. Sulfide-polymer composite electrolytes are composite materials obtained by combining sulfide electrolytes and polymer electrolytes. For example, a composite solid electrolyte 1 is formed by adding a sulfide electrolyte as a filler to a polymer electrolyte matrix; the sulfide electrolyte is, for example, Li6PS5Cl. 10 GeP2S 12 Li7P3S 11 Polymer electrolytes include Li6PS5Cl, etc., such as polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), or polyvinyl chloride (PVC).

[0050] In addition to the above structure, as shown in Figure 7, the solid electrolyte 1 of this embodiment also includes a functional layer 13. The functional layer 13 is disposed on the surface of the substrate 11 opposite to the grid layer 12. The functional layer 13 is configured to face the positive electrode of the solid-state battery, and the material of the functional layer 13 includes an oxide electrolyte. That is, the substrate 11 has two opposing surfaces, one of which has the grid layer 12 and the other has the functional layer 13. The grid layer 12 is configured to face the negative electrode, and the functional layer 13 is configured to face the positive electrode. With the above structural configuration, the good compatibility between the oxide electrolyte and the positive electrode active material can be utilized to suppress interfacial side reactions between the positive electrode and the solid electrolyte 1, resulting in good interfacial contact performance. Thus, through the combined action of the grid layer 12 and the functional layer 13 on opposite surfaces of the substrate 11, good contact performance is ensured between the solid electrolyte 1 and both the positive and negative electrodes.

[0051] 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.

[0052] Secondly, this application provides a solid-state battery. Referring to Figure 8, which is a schematic diagram of the structure of a solid-state battery according to an embodiment of this application, the solid-state battery includes: a positive electrode 3, a negative electrode 2, and a solid electrolyte 1. The solid electrolyte 1 is disposed between the positive electrode 3 and the negative electrode 2 to form a battery cell. The solid electrolyte 1 is the solid electrolyte 1 described in the first aspect; wherein at least a portion of the mesh layer 12 is disposed between the substrate 11 and the negative electrode 2.

[0053] Since the frequent thickness changes in solid-state batteries are mainly due to metal deposition or stripping on the negative electrode 2 side, a mesh layer 12 is provided between the substrate 11 and the negative electrode 2. This effectively utilizes the chambers 122 of the mesh layer 12 to contain the metal on the negative electrode 2 side, allowing the metal to be deposited in the chambers 122 during charging, rather than adding an additional metal deposition layer on the negative electrode 2 side. With this configuration, the distance between the substrate 11 and the negative electrode 2 no longer changes frequently due to metal deposition during charging and discharging, avoiding frequent changes in the thickness of the negative electrode and the battery, and ensuring a good cycle life for the solid-state battery.

[0054] Furthermore, the solid-state battery is an alkali metal solid-state battery, which includes lithium metal solid-state batteries, sodium metal solid-state batteries, or potassium metal solid-state batteries.

[0055] The following is an introduction to the positive and negative electrode plates 2.

[0056] The negative electrode 2 includes: a negative current collector and a negative active material layer disposed on at least one side surface of the negative current collector. The negative active material of the negative active material layer includes at least one of alkali metal, carbon-based material, and silicon-based material.

[0057] The positive electrode 3 includes: a positive current collector and a positive active material layer disposed on at least one side surface of the positive current collector. The positive active material layer includes: a layered oxide containing an alkali metal element, a polyanionic compound, or a Prussian blue-like compound. The alkali metal element includes lithium or sodium.

[0058] Optionally, the layered oxidation is a layered transition metal oxide, wherein the transition metal can be at least one selected from Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. Optionally, the layered transition metal oxide is, for example, Li. x MO2, where M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, and 0 < x ≤ 1.

[0059] Alternatively, the polyanionic compound may be a metal ion, a transition metal ion, or a tetrahedral (YO4) compound. n- A class of compounds with anionic units. The metal ion may be one of sodium, lithium, potassium, or zinc; the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y may be at least one of P, S, and Si; n represents (YO4). n- The price state.

[0060] Optionally, Prussian blue compounds can be a class of compounds containing sodium ions, transition metal ions, and cyanide ions (CN-). The transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. Examples of Prussian blue compounds include 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.

[0061] Preferably, the positive electrode active material layer comprises a positive electrode active material with a cell volume change rate ≤ 5%. A positive electrode active material with a cell volume change rate ≤ 5% is a material with small or zero volume strain. During charging and discharging, it can reduce the thickness change rate of the positive electrode 3, thereby working in conjunction with the solid electrolyte 1 to further control the thickness of the solid-state battery to remain constant or change very little during charging and discharging, and ensuring good contact performance at the interfaces between the positive electrode 3 and the solid electrolyte 1, and between the negative electrode 2 and the solid electrolyte 1. Preferably, the positive electrode active material comprises LiCoO2, whose cell volume change rate is less than 5%, which is beneficial for further controlling the thickness change of the solid-state battery during charging and discharging.

[0062] Furthermore, in the positive electrode 3, the positive electrode active material layer has a first region and a second region located on the outer periphery of the first region. The areal density of the positive electrode active material in the first region is higher than that 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.

[0063] In the first region, the areal density of the positive electrode active material is relatively higher, and correspondingly, the distribution of the first type of chambers 1221 in the middle region 122a is more sparse. Therefore, the first type of chambers 1221 in the middle region 122a can accommodate a larger volume of metal deposition, thus accommodating a relatively larger amount of metal deposition. In the second region, the areal density of the positive electrode active material is relatively lower, and correspondingly, the distribution of the second type of chambers 1222 in the edge region 122b is more dense. Therefore, although the second type of chambers 1222 in the edge region 122b can accommodate a smaller volume of metal deposition, it still meets the requirement of accommodating metals with lower areal density and relatively smaller deposition amounts in the first region.

[0064] Thirdly, embodiments of this application provide an energy storage device, which includes a solid-state battery as described in the second aspect.

[0065] Taking electrochemical energy storage as an example, this application provides an energy storage device 10. The energy storage device 10 is equipped with a set of chemical batteries. It mainly uses the chemical elements in the batteries as energy storage medium. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage medium. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electricity is released for use, or transferred to places with a shortage of electricity for use.

[0066] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. The corresponding types of energy storage devices 10 include:

[0067] (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can assist renewable energy power generation in meeting grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power regulation power source on the power supply side, energy storage power stations can achieve load matching of power in time and space, enhance the absorption capacity of renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy power generation, and are of great significance in power grid system backup, alleviating peak load power supply pressure and peak regulation and frequency regulation.

[0068] (2) Energy storage containers applied on the grid side mainly function as peak shaving, frequency regulation and grid congestion relief. In terms of peak shaving, they can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak electricity load period, thereby achieving a balance between power production and consumption.

[0069] (3) Small energy storage cabinets applied to the electricity consumption side mainly function as self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improvement of power supply reliability. Depending on the application scenario, electricity consumption side energy storage 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 peak-valley price arbitrage and capacity cost management. In the electricity market implementing peak-valley pricing, 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 price arbitrage can be achieved, reducing electricity costs. In addition, industrial enterprises subject to two-part tariffs can use the energy storage system 100 to store energy during off-peak hours and discharge during peak loads, thereby reducing peak power and the maximum demand declared, achieving the goal of reducing capacity electricity costs. Household photovoltaics with energy storage can improve the level of self-consumption of electricity. Due to high electricity prices and poor power supply stability, the demand for household photovoltaic installations is driven. Given that photovoltaic power generation occurs during the day, while user load is generally higher at night, configuring energy storage can better utilize photovoltaic power, improve self-consumption levels, and reduce electricity costs. Furthermore, energy storage is needed in areas such as communication base stations and data centers for backup power.

[0070] Please refer to Figure 9, which is a structural schematic diagram of a residential energy storage system 100 according to an embodiment of this application. This application provides a residential energy storage system 100, which includes a power conversion device 20 (photovoltaic panel), a first user load 30 (streetlight), a second user load 40 (e.g., household appliances such as air conditioners), and an energy storage device 10. The energy storage device 10 is a small energy storage box that can be wall-mounted to an outdoor wall. Specifically, the photovoltaic panel can convert solar energy into electrical energy during periods of low electricity prices, and the energy storage device 10 is used to store this electrical energy and supply it to streetlights and household appliances during peak electricity prices, or to provide power during power outages / power failures.

[0071] Please refer to Figure 10, which is a schematic diagram of the structure of an energy storage system 100 according to an embodiment of this application. The embodiment of Figure 10 is described using a shared energy storage scenario on the generation / distribution side as an example. The energy storage device 10 of this application is not limited to its generation / distribution side energy storage scenario.

[0072] This application provides an energy storage system 100, which includes a high-voltage cable 50, a first power conversion device 60, a second power conversion device 70, and the energy storage device 10 provided in this application. During power generation, the first power conversion device 60 and the second power conversion device 70 convert other forms of energy into electrical energy, which is then connected to the high-voltage cable and supplied to the power consumption side of the distribution network. When the power load is low and the first power conversion device 60 and the second power conversion device 70 generate excess power, the excess electricity is stored in the energy storage device 10, reducing wind and solar curtailment rates and improving the absorption of new energy power generation. When the power load is high, the power grid issues an instruction to transmit the electricity stored in the energy storage device 10, along with the high-voltage cable 50, in a grid-connected mode to supply power to the power consumption side. This provides various services for power grid operation, such as peak shaving, frequency regulation, and backup, fully leveraging the peak shaving function of the power grid, promoting peak shaving and valley filling, and alleviating the power supply pressure on the power grid.

[0073] Optionally, the first power conversion device 60 and the second power 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 electrical energy.

[0074] The number of energy storage devices 10 can be multiple, and the multiple energy storage devices 10 can be connected in series or in parallel. The multiple energy storage devices 10 are supported and electrically connected by an isolation plate (not shown). In this embodiment, "multiple" means two or more. An energy storage box can also be provided on the outside of the energy storage device 10 to house the energy storage device 10.

[0075] Optionally, the energy storage device 10 may include, but is not limited to, battery modules, battery packs, battery systems, etc. The actual application form of the energy storage device 10 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 10. This application embodiment only uses a multi-cell battery as an example for illustration. When the energy storage device 10 is a single battery, the energy storage device 10 may be at least one of cylindrical batteries, prismatic batteries, etc.

[0076] The solution of this application will be further described below with reference to specific embodiments and experimental data.

[0077] Example 1

[0078] This embodiment provides a solid-state battery, which is prepared by the following method.

[0079] Preparation of the positive electrode sheet: The positive electrode active material NCM811, conductive agent Ketjen Black, and binder PVDF were mixed evenly in a stirring device at a mass ratio of 80:10:10. Then, the solvent N-methylpyrrolidone was added and stirred to form a uniform positive electrode slurry with a solid content of 40%. The positive electrode slurry was coated onto an aluminum foil positive electrode current collector, dried, and cold-pressed to obtain the positive electrode sheet. The areal specific capacity of the positive electrode active material was controlled to be 2 mAh / cm². 2 .

[0080] Negative electrode: Lithium metal sheet.

[0081] Solid electrolyte: Li is placed in an inert atmosphere. 10 GeP2S 12 After the powder is filled into the die-casting mold, it is die-cast under a pressure of 100MPa for 1 minute to form an integral substrate and a grid layer, thus obtaining a solid electrolyte. The grid layer is located on one side surface of the substrate and includes a skeleton body and several chambers separated by the skeleton body.

[0082] Assemble a full cell: Stack the positive electrode, solid electrolyte, and negative electrode in sequence, with the solid electrolyte located between the positive and negative electrodes, to assemble a full cell.

[0083] Examples 2 to 4

[0084] The difference from Example 1 is that the thickness of the mesh layer is different.

[0085] Example 5

[0086] The difference from Example 3 is that the orthographic projection shape of the chamber in the grid layer facing the substrate is different.

[0087] Example 6

[0088] 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.

[0089] Examples 7 to 9

[0090] The difference from Example 3 is that the solid electrolyte also includes a functional layer disposed on the other side surface of the substrate. The preparation method includes: after pressing the substrate and the mesh layer into an integral mold, uniformly sprinkling oxide electrolyte powder on the other side surface of the substrate, and then pressing and casting at 900MPa for 5 minutes to obtain a solid electrolyte with a mesh layer on one side surface of the substrate and a functional layer on the other side surface.

[0091] Examples 10-11

[0092] The difference from Example 9 is that the positive electrode active material is different.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that the solid electrolyte only contains a substrate and does not have a mesh layer.

[0095] Performance Testing

[0096] (1) Test of thickness change rate of positive or negative electrode sheet

[0097] After battery assembly, the battery is charged at a constant current to the set upper limit voltage (3.5V at 1000mA) using a charge / discharge tester. Then, the battery is disassembled in a glove box, and the thickness T of the positive or negative electrode is measured. 充 Subsequently, after discharging the same type of battery at a constant current to the set lower limit voltage (discharging at a constant current to 1.5V under 1000mA conditions), the battery was disassembled in a glove box and the thickness T of the positive or negative electrode was measured. 放 Specify T 放 As the reference thickness for the positive or negative electrode, then (T) 充 -T 放 ) / T 放 The absolute value is the rate of change in the thickness of the positive or negative electrode.

[0098] (2) Cyclic capacity retention test

[0099] After the battery is assembled, a constant current charge-discharge test is performed on the battery using a charge-discharge tester. The test temperature is 25℃, the cycle rate is 1C (i.e., both the charge rate and the discharge rate are 1C), and the charging voltage is from 1.5V to 3.5V. The capacity retention rate after 100 cycles is calculated. The ratio of the battery's discharge capacity on the 100th cycle to its discharge capacity on the 1st cycle is the cycle capacity retention rate after 100 cycles.

[0100] Table 1. Solid-state battery setup parameters and performance test results for the examples and comparative examples. Note: 1. In Table 1, “ / ” indicates that the relevant parameter does not exist.

[0101] 2. In Table 1, LLZO 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 0.1 O2, NCM523 refers to LiNi 0.5 Co 0.2 Mn 0.3 O2.

[0102] Comparing Comparative Example 1 and the various embodiments, it can be seen that the solid electrolyte in Comparative Example 1 only uses a substrate, i.e., a conventional planar solid electrolyte. The battery using this solid electrolyte has the highest rate of change in negative electrode thickness during charge and discharge, and the lowest cycle capacity retention rate. In contrast, the solid electrolytes in the various embodiments include a substrate and a grid layer, which significantly reduces the rate of change in negative electrode thickness during charge and discharge, and also improves the cycle capacity retention rate to some extent.

[0103] Comparing Examples 1 to 4, it can be seen that increasing the thickness of the solid electrolyte mesh 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 mesh layer in the solid electrolyte increases to a certain extent, the cycle capacity retention rate of the solid-state battery no longer continues to improve. This is because once the total volume of the mesh layer chamber exceeds the volume required for alkali metal deposition on the negative electrode side, further increasing the mesh layer thickness can no longer reduce the rate of change of the negative electrode thickness. Instead, it will lead to a decrease in the density of deposited alkali metal and an increase in side reactions, thus affecting the cycle capacity retention rate and preventing further improvement.

[0104] Comparing Examples 3, 5, and 6, it can be seen that adjusting the shape of the solid electrolyte mesh layer chamber has a certain impact on both the rate of change of the negative electrode thickness and the cycle capacity retention rate. Preferably, when the orthographic projection shape of the chamber changes from rectangular to hexagonal, it can better match the growth characteristics of metal deposition on the negative electrode side, increasing the density of deposited alkali metal, reducing the rate of change of the negative electrode thickness, and increasing the cycle capacity retention rate. Preferably, when the cross-sectional shape of the chamber changes from rectangular to trumpet-shaped, it is beneficial to improve the densification of metal deposition within the chamber during solid-state battery charging, reducing the rate of change of the negative electrode thickness and increasing the cycle capacity retention rate.

[0105] Comparing Examples 3 and 7 through 9, it can be seen that providing a functional layer on the other side of the solid electrolyte substrate is beneficial for improving the battery's cycle capacity retention. Through the above structural configuration, the good compatibility between the oxide electrolyte and the positive electrode active material can be utilized to suppress interfacial side reactions between the positive electrode and the solid electrolyte, resulting in good interfacial contact performance. Preferably, when the functional layer uses LATPO, the battery's cycle performance is even better.

[0106] Comparing Examples 9 to 11, it can be seen that adjusting the type of positive electrode active material has a certain impact on both the positive electrode thickness change rate and the battery cycle capacity retention rate. A decrease in the positive electrode cell volume change rate leads to a decrease in the positive electrode thickness change rate during charging and discharging, resulting in better contact performance at the positive electrode-solid electrolyte interface and an increased battery cycle capacity retention rate. Preferably, when LiCoO2 is selected as the positive electrode active material, the overall battery performance is better.

[0107] The technical solutions disclosed in the embodiments of this application have been described in detail above. Specific examples have been used in this document to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A solid electrolyte for use in a solid-state battery, wherein, The solid electrolyte includes: Base; A mesh layer is disposed on at least one side surface of the substrate. The mesh layer includes a skeleton body and a plurality of chambers separated by the skeleton body. At least a portion of the chambers have their openings configured to face the negative electrode of the solid-state battery.

2. The solid electrolyte according to claim 1, wherein, The orthographic shape of the chamber facing the base includes at least one of polygon, circle, and ellipse.

3. The solid electrolyte according to claim 2, wherein, The orthographic shape of the chamber facing the base includes a hexagon.

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

5. The solid electrolyte according to claim 1, wherein, The chamber has a central region and an edge region located on the periphery of the central region. The chamber includes a plurality of first-type chambers located in the central 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.

6. The solid electrolyte according to claim 1, wherein, The thickness of the mesh layer is 1μm to 50μm.

7. The solid electrolyte according to claim 1, wherein, The substrate and the mesh layer are an integrated structure.

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

9. The solid electrolyte according to any one of claims 1 to 8, wherein, The solid electrolyte further includes a functional layer disposed on the surface of the substrate opposite to the mesh layer, the functional layer being configured to face the positive electrode of the solid-state battery, and the material of the functional layer including an oxide electrolyte.

10. The solid electrolyte according to claim 9, wherein, 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, wherein, The solid-state battery includes: Positive electrode sheet; Negative electrode sheet; A solid electrolyte, wherein the solid electrolyte is disposed between the positive electrode and the negative electrode to form a battery cell, and the solid electrolyte is the solid electrolyte as described in any one of claims 1 to 10; At least a portion of the mesh layer is disposed between the substrate and the negative electrode sheet.

12. The solid-state battery according to claim 11, wherein, The negative electrode sheet includes: a negative electrode current collector, and a negative electrode active material layer disposed on at least one 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 metal, carbon-based material, and 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, wherein, The positive electrode sheet includes: a positive current collector and a positive active material layer disposed on at least one side surface of the positive current collector. The positive active material of the positive active material layer includes: a layered oxide containing alkali metal elements, a polyanionic compound, or a Prussian blue compound.

14. The solid-state battery according to claim 13, wherein, The positive electrode active material layer comprises the positive electrode active material with a cell volume change rate ≤ 5%; and / or, The positive electrode active material layer has a first region and a second region located on the outer periphery of the first region, wherein the areal density of the positive electrode active material in the first region is higher than the areal density of the positive electrode active material in the second region; The solid electrolyte has a chamber with a central 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 central 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, wherein, The energy storage device includes a solid-state battery as described in any one of claims 11 to 14.

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