Battery pole piece, solid-state battery cell, preparation method and application

Abstract

The present application relates to the technical field of solid-state battery, and particularly relates to a battery pole piece, a solid-state battery cell, a preparation method and application. The battery pole piece provided by the present application comprises a current collector, an active material layer located on at least one side of the current collector, and active material particles included in the active material layer; the active material particles are at least partially coated with a first coating layer, and the first coating layer is at least partially coated with a second coating layer; raw materials of the first coating layer include lithium-containing composite oxide and end-thiol-based silane; and raw materials of the second coating layer include lithium salt and first organic polymer monomer. The pole piece has extremely high densification, and can provide excellent cycle stability and rate performance for a battery cell using the pole piece.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, specifically to a battery electrode, a solid-state battery cell, its preparation method, and its application. Background Technology

[0002] As users place increasingly higher demands on the energy density and lifespan of rechargeable batteries, solid-state batteries have become a major development direction. The core of solid-state batteries is to replace the flammable and explosive organic liquid electrolytes used in traditional lithium-ion batteries with solid electrolytes. The rigidity and non-flammability of solid electrolytes allow for compatibility with higher-capacity cathode and anode materials, significantly improving battery energy density and extending driving range. However, current technology still presents many challenges before practical application. Firstly, unlike traditional lithium-ion batteries where electrolytes create a good ion-contact interface between the electrolyte and electrode materials, solid-state batteries use rigid solid particles for both the electrolyte and active electrode materials (positive and negative electrodes). During charge-discharge cycles, the electrode materials inevitably expand and contract in volume due to lithium insertion and extraction. This microscopic deformation easily leads to porosity and poor contact at the solid-solid interface between electrolyte and active material particles, ultimately disrupting ion transport pathways, increasing internal resistance, decreasing rate performance, and reducing cycle capacity retention. On the other hand, solid-state batteries require the stacking and assembly of positive and negative electrodes, and the formation of an all-solid-state battery using an isostatic pressing process to provide ultra-high pressure. However, solid-state batteries often exhibit overhang designs (the negative electrode portion extends beyond the positive electrode portion), making the larger negative electrode edges prone to collapse under pressure and electrolyte membrane rupture. While existing technologies employ methods to partially fill the overhang region to reduce collapse, the isostatic pressing process in actual manufacturing involves further compaction of the electrode under high pressure due to the numerous pores within the electrode. This results in a decrease in height due to pressure, and the height change of the filler in the overhang region cannot match the change in electrode height, still posing a possibility of collapse and electrolyte membrane rupture. These risks can lead to contact between the positive and negative electrodes, short circuits, and severely limit the scaling up of all-solid-state battery sizes. Summary of the Invention

[0003] One objective of this invention is to provide a battery electrode to solve problems such as poor solid-solid interface contact in existing solid-state batteries, uneven electrode height causing collapse in some areas, and consequently increased internal resistance, decreased rate performance, and reduced cycle performance. A second objective is to provide a method for preparing the aforementioned battery electrode. A third objective is to provide a solid-state battery cell. A fourth objective is to provide a method for preparing the aforementioned solid-state battery cell. A fifth objective is to provide a solid-state battery. A sixth objective is to provide an electrical device.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention provides a battery electrode sheet, comprising a current collector and an active material layer located on at least one side of the current collector, the active material layer comprising active material particles;

[0006] The active material particles are at least partially coated with a first coating layer, and at least partially coated with a second coating layer; the raw materials of the first coating layer include lithium-containing composite oxide and thiol-terminated silane; the raw materials of the second coating layer include lithium salt and a first organic polymer monomer;

[0007] The lithium-containing composite oxide includes at least one of Li2ZrO3, Li2TiO3, LiTaO3, and LiAlO2;

[0008] The terminal mercapto silanes include at least one of 3-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane.

[0009] The lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium dioxaborate, lithium difluoroborate, and lithium tetrafluoroborate.

[0010] The first organic polymer monomer comprises a compound having a functionality of 1 to 3 acrylate groups.

[0011] In the solid-state battery cell provided by this invention, the particle size of the active material particles does not need to be specifically specified, as long as it conforms to the size of commonly used electrode active material particles; the thickness of the active material layer and the current collector also does not need to be specifically specified, as conventional thicknesses in the art can be used.

[0012] In one alternative implementation, the battery electrode satisfies at least one of the following conditions:

[0013] (1) The first coating layer satisfies the following relationship:

[0014] 0.7≤(b% / N2) / (n×a% / N1)≤1;

[0015] Wherein, a% is the percentage of the mass of the lithium-containing composite oxide to the mass of the active material particles when the first coating layer is prepared;

[0016] b% is the percentage of the mass of the terminal thiol silane to the mass of the active material particles during the preparation of the first coating layer;

[0017] n is the molar number of oxygen atoms per mole of the lithium-containing composite oxide;

[0018] N1 is the molar mass of the lithium-containing composite oxide used in the preparation of the first coating layer, in g / mol;

[0019] N2 is the molar mass of the terminal mercapto silane used in the preparation of the first coating layer, in g / mol;

[0020] Typically, without limitation, b% = mass of terminal thiol silane / mass of active material particles × 100%, which can be calculated after weighing during the preparation stage, and n can be obtained from the corresponding chemical formula of the lithium-containing composite oxide. a% = mass of lithium-containing composite oxide / mass of active material particles × 100%, the mass of lithium-containing composite oxide can be obtained by subtracting the mass of active material particles (denoted as m) from the mass of active material particles (denoted as m) after coating with lithium-containing composite oxide, that is, the mass of lithium-containing composite oxide = m1 - m;

[0021] (2) In the raw materials of the second coating layer, the mass ratio of the first organic polymer monomer to the active material particles is 2~8:60~85;

[0022] (3) In the raw materials of the second coating layer, the mass of lithium salt is 2% to 10% of the mass of the first organic polymer monomer;

[0023] (4) The active material layer also includes solid electrolyte particles;

[0024] In the battery electrode provided by this invention, the particle size of the solid electrolyte particles does not need to be specifically specified, as long as it conforms to the size of solid electrolyte particles in commonly used solid battery electrode sheets.

[0025] (5) The active material particles include positive electrode active material particles or negative electrode active material particles;

[0026] (6) The active material layer also includes a conductive agent and a binder. The amount of conductive agent and binder shall conform to the conventional amount in the art; typically, without limitation, the mass ratio of active material particles, conductive agent and binder in the active material layer is 60~85:0.5~5:0.5~5; the conductive agent includes at least one of conductive graphite, conductive carbon black, acetylene black, carbon nanotubes, Ketjen black, graphene, carbon nanofibers, polyethylene dioxythiophene, polystyrene sulfonic acid and sodium polystyrene sulfonate; the binder includes at least one of polyvinylidene fluoride, polyvinyl alcohol, polytetrafluoroethylene, sodium hydroxymethyl cellulose, styrene-butadiene rubber, polyacrylic acid, polystyrene and polyisobutylene.

[0027] In a further optional embodiment, the first coating layer satisfies the following relationship: 0.85≤(b% / N2) / (n×a% / N1)≤1.

[0028] In one alternative implementation, 0.2% ≤ a% ≤ 13%.

[0029] In one alternative implementation, 1% ≤ b% ≤ 32%.

[0030] In one alternative implementation, 2 ≤ n ≤ 4.

[0031] In one alternative implementation, 60 ≤ N1 ≤ 250.

[0032] In one alternative implementation, 100 ≤ N2 ≤ 500.

[0033] In one optional embodiment, the mass ratio of the solid electrolyte particles to the active material particles in the active material layer is 5~30:60~85.

[0034] In one optional embodiment, the solid electrolyte particles include at least one of sulfide solid electrolyte particles, oxide solid electrolyte particles, and halide solid electrolyte particles.

[0035] The solid-state battery cell provided by this invention includes sulfide solid electrolyte particles comprising at least one of glassy sulfide solid electrolyte, glass-ceramic sulfide solid electrolyte, and crystalline sulfide solid electrolyte. Specifically, the crystalline sulfide solid electrolyte includes at least one of thio-LISICON type solid electrolyte, Li-argyrodite type solid electrolyte, and LGPS type solid electrolyte. The general formula for thio-LISICON type solid electrolyte can be written as Li... 4-n A 1-n B nS4, wherein A includes one or more of Si, Sn, Ge, and Zr, and B includes at least one of O, P, Al, Zn, and Ga; n is 0~1. One of the general chemical formulas for the doped modified derivatives of Li-argyrodite type solid electrolytes is LiPSZX, wherein Z includes at least one of O, Cu, Zn, Bi, Sn, Al, Ce, and In, and X includes at least one of F, Cl, Br, and I. The oxide solid electrolyte particles include at least one of garnet-type solid electrolytes, perovskite-type solid electrolytes, NASICON-type solid electrolytes, and LISICON-type solid electrolytes. For example, it can be Li... x1 La3Zr y1 A' z1 O 12 Li x2 La 3-y2 B y2 Zr z O 12 The electrolyte is composed of LiGeTi(PO4)3, wherein A' is at least one of Ta, Nb, Mg, Ti, Te, and W; B is at least one of Ca, Rb, Al, and Ga; and the values ​​of x1, x2, y1, y2, z1, and z2 are all in the range of 0 to 1. The halide solid electrolyte particles include LiQ, Li2MQ4, Li3M'Q6, and Li... x3 M” y3 Ln z3 At least one of Cl3; wherein Q is at least one of F, Cl, Br, I, M is at least one of Mg, Mn, Fe, Zn, and Cd, M' is at least one of O, In, Y, Yb, Sc, Ho, and Er, M” is at least one of Ta, Zr, Ca, and Al, Ln is at least one of La, Ce, Pr, Nd, and Sm, x3 is 0~1, y3 is 0~1, and z3 is 0~1.

[0036] In one alternative embodiment, the first organic polymer monomer includes at least one of isobornyl acrylate (IBOA), 1,6-hexanediol diacrylate (HDDA), dipropylene glycol diacrylate (DPGDA), pentaerythritol triacrylate (PETA), and trimethylolpropane triacrylate (TMPTA).

[0037] In one optional embodiment, the positive electrode active material particles include at least one of nickel-cobalt-manganese ternary materials, nickel-iron-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium iron phosphate materials, and lithium manganese oxide materials.

[0038] In one optional embodiment, the negative electrode active material particles include at least one of silicon-based materials and carbon-based materials.

[0039] Secondly, the present invention provides a method for preparing the above-mentioned battery electrode, comprising the following steps:

[0040] S1: Coating the surface of the active material particles with a lithium-containing composite oxide to obtain the first pretreated active material particles;

[0041] S2: The active material particles that have undergone the first pretreatment are mixed with terminal mercapto silanes to obtain active material particles with a first coating layer;

[0042] S3: Mix the active material particles with the first coating layer, the first organic polymer monomer, the first initiator, and the lithium salt, and perform a cross-linking reaction to obtain an active material mixture. Press the mixture to obtain an active material layer.

[0043] S4: The active material layer is composited onto the current collector and photocured to obtain the battery electrode.

[0044] In one optional embodiment, the mass of the first initiator is 0.5% to 5% of the mass of the first organic polymer monomer.

[0045] In an optional embodiment, the first initiator includes at least one of α,α'-dimethylbenzoyl ketal, α,α'-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxy-cyclohexylbenzophenone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl-1-propanone, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0046] In one optional embodiment, in step S4, the photocuring time is 5-600 s, and the ultraviolet irradiation wavelength used for photocuring is 395-410 nm.

[0047] In one optional embodiment, in step S3, the crosslinking reaction takes 30-50 minutes and the temperature is 50-100°C.

[0048] In one alternative implementation, the coating method in S1 includes atomic deposition.

[0049] In one alternative embodiment, in step S3, solid electrolyte particles are added before pressing.

[0050] In one optional embodiment, in step S3, a conductive agent and a binder are added before pressing.

[0051] Thirdly, the present invention provides a solid-state battery cell, comprising the above-mentioned battery electrode sheet, or a battery electrode sheet prepared by the above-mentioned battery electrode sheet preparation method.

[0052] In one optional embodiment, the solid-state battery cell includes at least one unit cell, the unit cell including a positive electrode, a negative electrode, a solid electrolyte membrane, and edge filler;

[0053] The positive electrode, solid electrolyte membrane, and negative electrode are stacked together, and the area around the negative electrode that extends beyond the positive electrode to at least one side is the overhang region.

[0054] The edge filler is located in the void area corresponding to the overhang region;

[0055] The raw material for the edge filler includes a second organic polymer monomer;

[0056] The positive electrode and / or negative electrode are the aforementioned battery electrode, or battery electrode prepared by the aforementioned battery electrode preparation method. That is, in the solid-state battery cell provided by the present invention, at least one of the positive electrode and negative electrode is the aforementioned battery electrode, or battery electrode prepared by the aforementioned battery electrode preparation method; when the positive electrode is the aforementioned battery electrode, or battery electrode prepared by the aforementioned battery electrode preparation method, the active material particles used in the battery electrode are positive electrode active material particles; when the negative electrode is the aforementioned battery electrode, or battery electrode prepared by the aforementioned battery electrode preparation method, the active material particles used in the battery electrode are negative electrode active material particles.

[0057] In one alternative embodiment, the second organic polymer monomer comprises a compound having a functionality of more than 3 acrylate groups.

[0058] In one alternative embodiment, the second organic polymer monomer comprises a compound having a functionality of 4 to 6 acrylate groups.

[0059] In one optional embodiment, in each unit cell, the solid electrolyte membrane is located between the negative electrode and the positive electrode, and on the side of the negative electrode away from the positive electrode. For ease of assembly, during the manufacturing process, the solid electrolyte membrane can be directly prepared on the upper and lower sides of the negative electrode and then assembled with the positive electrode; or, in each unit cell, the solid electrolyte membrane is located between the negative electrode and the positive electrode, and on the side of the positive electrode away from the negative electrode. For ease of assembly, during the manufacturing process, the solid electrolyte membrane can be directly prepared on the upper and lower sides of the positive electrode and then assembled with the negative electrode.

[0060] In the solid-state battery cell provided by this invention, when the solid electrolyte membrane is located on the upper and lower sides of the negative electrode in a single cell, the height of the edge filler filling the overhang area is greater than or equal to the height of the positive electrode, and may exceed the height of the positive electrode by 0-3 μm. When the solid electrolyte membrane is located on the upper and lower sides of the positive electrode in a single cell, the height of the edge filler filling the overhang area is greater than or equal to the height of the positive electrode plus two layers of solid electrolyte membrane, and may exceed the height of the positive electrode plus two layers of solid electrolyte membrane by 0-3 μm. Considering the filling effect of the edge filler, its height must at least be consistent with the height of the positive electrode or the positive electrode plus two layers of solid electrolyte membrane. However, considering that the electrode may be further compacted, the height of the edge filler exceeding the height of the positive electrode or the positive electrode plus two layers of solid electrolyte membrane cannot be too high.

[0061] In one alternative implementation, the width of one side of the overhang region is 2-5 mm.

[0062] In one alternative embodiment, the second organic polymer monomer includes at least one of dipentaerythritol hexaacrylate (DPHA) and pentaerythritol tetraacrylate (PETTA).

[0063] Fourthly, the present invention provides a method for preparing the above-mentioned solid-state battery cell, comprising the following steps:

[0064] ① The second organic polymer monomer and the second initiator are mixed to obtain a mixture of edge filler raw materials;

[0065] ② The positive or negative electrode sheet is combined with a solid electrolyte membrane and then stacked. An edge filler material mixture is placed into the overhang region; photocuring is performed to obtain a unit cell.

[0066] In the method for preparing the solid-state battery cell provided by this invention, at least one of the positive electrode and the negative electrode is either the aforementioned battery electrode or a battery electrode prepared by the aforementioned battery electrode preparation method. When the positive electrode or the negative electrode used is not the aforementioned battery electrode or a battery electrode prepared by the aforementioned battery electrode preparation method; the method for preparing the positive electrode includes pressing positive active material particles to obtain a positive active material layer, and bonding the positive active material layer to a positive current collector to obtain a positive electrode; before pressing, solid electrolyte particles, a conductive agent, and a binder are added; the method for preparing the negative electrode includes pressing negative active material particles to obtain a negative active material layer, and bonding the negative active material layer to a negative current collector to obtain a negative electrode; before pressing, solid electrolyte particles, a conductive agent, and a binder are added.

[0067] In one optional embodiment, the mass of the second initiator is 0.5% to 5% of the mass of the second organic polymer monomer.

[0068] In an optional embodiment, the second initiator includes at least one selected from α,α'-dimethylbenzoyl ketal, α,α'-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxy-cyclohexylbenzophenone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl-1-propanone, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0069] In one optional embodiment, in step ②, the photocuring time is 10~60s, and the ultraviolet irradiation wavelength used for photocuring is 395~410nm.

[0070] In one optional implementation, after step ②, a step of stacking several unit cells is further included.

[0071] Fifthly, the present invention provides a solid-state battery, comprising the above-mentioned battery electrode, or a battery electrode prepared by the above-mentioned battery electrode preparation method, or the above-mentioned solid-state battery cell, or a solid-state battery cell prepared by the above-mentioned solid-state battery cell preparation method.

[0072] In a sixth aspect, the present invention provides an electrical device including the above-mentioned solid-state battery, wherein the solid-state battery serves as a power supply for the electrical device.

[0073] The beneficial effects of this invention are:

[0074] (1) The battery electrode provided by the present invention includes a current collector, an active material layer located on at least one side of the current collector, the active material layer including active material particles; at least a portion of the surface of the active material particles is coated with a first coating layer, and at least a portion of the surface of the first coating layer is coated with a second coating layer; the raw material of the first coating layer includes a lithium-containing composite oxide and a thiol-terminated silane; the raw material of the second coating layer includes a lithium salt and a first organic polymer monomer; the lithium-containing composite oxide includes at least one of Li2ZrO3, Li2TiO3, LiTaO3, and LiAlO2; the thiol-terminated silane includes at least one of 3-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane; the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium dioxaborate, lithium difluoroborate, and lithium tetrafluoroborate; the first organic polymer monomer includes a compound with a functionality of 1 to 3 acrylate groups. The battery electrode provided by this invention has an extremely high degree of internal density, which can effectively avoid the deformation caused by electrode shrinkage during the high-pressure forming process of solid-state batteries, and further short circuits. When applied to batteries, it can effectively suppress battery expansion during charging and discharging, and can provide lower resistance, good long-term cycle stability and rate performance.

[0075] Specifically, in the second coating layer on the surface of the active material particles, the first organic polymer, made from the first organic polymer monomer, enables dynamic adhesion between the materials in the active material layer, forming a nearly pore-free, highly dense all-solid-state electrode. This reduces interfacial impedance and exhibits excellent electrochemical performance and cycle stability. The raw materials for the second coating layer include lithium salt and the first organic polymer monomer. This allows the lithium salt to disrupt the ordered arrangement of monomer molecules during the preparation of the second coating layer, reducing crystallinity and increasing amorphous regions. This enhances the flexibility of the first organic polymer, facilitating dynamic adhesion between the second coating layer and other particles in the active material layer. Furthermore, coating the surface of the active material particles with the second coating layer avoids direct contact between the active material and the electrolyte, slows down interfacial reactions, and suppresses oxygen release from oxidized positive electrode active materials at high temperatures, thus helping to improve the cycle stability and thermal safety performance of the battery. In the first coating layer, the terminal mercapto silane anchors the second coating layer on the surface of the first coating layer through Si-OM covalent bonds and thioether bonds, where M is a non-lithium metal in the lithium-containing composite oxide. Specifically, oxygen in lithium-containing composite oxides readily undergoes hydrolysis to generate hydroxide ions. These hydroxide ions further react with terminal thiol-based silanes to form Si-OM (where M is a non-lithium metal in the composite oxide) covalent bonds through a condensation reaction. The terminal thiol groups (-SH) then undergo cross-linking reactions with the first organic polymer monomer, enabling the second coating layer to precisely encapsulate the surface of the active particles. Simultaneously, the cross-linking reaction also enhances the stability of the second coating layer.

[0076] The lithium-containing composite oxide includes at least one of Li2ZrO3, Li2TiO3, LiTaO3, and LiAlO2. Using a lithium-containing composite oxide with lithium conductivity can help improve the ionic conductivity of the battery.

[0077] The first organic polymer monomer comprises compounds with acrylate groups having a functionality of 1 to 3. The organic polymer obtained by polymerizing the first organic polymer monomer needs to have low hardness to facilitate dynamic adhesion between the particles of the active material layer. In the three-dimensional network framework formed by the first organic polymer, its internal -COC- segments can react with lithium ions (Li) dissociated from the lithium salt. + Coordination facilitates the dissociation of lithium salts and the transport of Li through localized movement of chain segments. + This improves ionic conductivity.

[0078] (2) The battery electrode provided by the present invention has a first coating layer that satisfies the following relationship: 0.7≤(b% / N2) / (n×a% / N1)≤1, where a% is the percentage of the mass of the lithium-containing composite oxide in the preparation of the first coating layer to the mass of the active material particles; b% is the percentage of the mass of the terminal mercaptosilane in the preparation of the first coating layer to the mass of the active material particles; n is the molar number of oxygen atoms per mole of the lithium-containing composite oxide; N1 is the molar mass of the lithium-containing composite oxide used in the preparation of the first coating layer, in g / mol; and N2 is the molar mass of the terminal mercaptosilane used in the preparation of the first coating layer, in g / mol. By specifying the relationship that the lithium-containing composite oxide and the terminal mercaptosilane in the first coating layer must satisfy through the above relationship, it can be ensured that the terminal mercaptosilane can effectively achieve the connection with the second coating layer, and will not affect the lithium-ion transport due to excessive use, thereby affecting the rate performance of the overall battery. More preferably, the first coating layer satisfies the following relationship: 0.85≤(b% / N2) / (n×a% / N1)≤1; which can further improve the rate performance of the battery.

[0079] (3) In the battery electrode provided by the present invention, 0.2%≤a%≤13%; 1%≤b%≤32%. Further control over the numerical range of a% and b% is beneficial to the realization of the above-mentioned relationship range.

[0080] (4) In the battery electrode provided by the present invention, the mass ratio of the first organic polymer monomer to the active material particles in the raw material of the second coating layer is 2~8:60~85; the mass of the lithium salt in the raw material of the second coating layer is 2%~10% of the mass of the first organic polymer monomer. The control of the mass ratio of lithium salt, first organic polymer monomer and active material particles within the above range can further improve the electrical performance of solid-state batteries.

[0081] (5) In the battery electrode provided by the present invention, the active material layer further includes solid electrolyte particles. Adding solid electrolyte particles to the active material layer can help improve the density of the electrode and improve its conductivity.

[0082] (6) The method for preparing the battery electrode provided by the present invention includes the following steps: S1: coating the surface of the active material particles with a lithium-containing composite oxide to obtain the active material particles with a first pretreatment; S2: mixing the active material particles with the first pretreatment with a thiol-terminated silane to obtain the active material particles with a first coating layer; S3: mixing the active material particles with the first coating layer, a first organic polymer monomer, a first initiator, and a lithium salt, performing a crosslinking reaction to obtain an active material mixture, pressing it to obtain an active material layer; S4: compositing the active material layer onto a current collector, photocuring it to obtain the battery electrode. The method for preparing the battery electrode provided by the present invention has simple steps and is convenient for large-scale production.

[0083] (7) In the above-mentioned method for preparing the battery electrode provided by the present invention, the mass of the first initiator is 0.5% to 5% of the mass of the first organic polymer monomer; controlling the amount of the first initiator within the above range can help control the degree of crosslinking of the first organic polymer, retain its chain segment mobility, make it have better dynamic characteristics, and be more conducive to ion conduction during use.

[0084] (8) In the above-mentioned method for preparing battery electrode sheets provided by the present invention, the coating method in S1 includes atomic layer deposition. Atomic layer deposition can make the prepared lithium-containing composite oxide more tightly coated on the surface of positive electrode active material particles or negative electrode active material particles; during the atomic layer deposition process, water vapor can be introduced to convert oxygen in the lithium-containing composite oxide into hydroxide ions.

[0085] (9) In the above-mentioned method for preparing the battery electrode provided by the present invention, solid electrolyte particles are added before pressing; conductive agent and binder are also added before pressing. That is, in the above-mentioned method for preparing the battery electrode provided by the present invention, solid electrolyte particles, conductive agent and binder can be mixed with active material particles, first organic polymer monomer, first initiator and lithium salt, without the need to first prepare active material particles coated with a second coating layer, and then mix them with conductive agent, binder and solid electrolyte particles to continue preparation, the preparation method is simple.

[0086] (10) The solid-state battery cell provided by the present invention includes the above-mentioned battery electrode or the battery electrode prepared by the above-mentioned battery electrode preparation method. The solid-state battery cell can give full play to the excellent performance of the above-mentioned battery electrode or the battery electrode prepared by the above-mentioned battery electrode preparation method, and has low expansion during charging and discharging, low resistance, good long-term cycle stability and rate performance.

[0087] (11) The solid-state battery cell provided by the present invention includes at least one unit cell, wherein the unit cell includes a positive electrode, a negative electrode, a solid electrolyte membrane, and an edge filler; the positive electrode, the solid electrolyte membrane, and the negative electrode are stacked, and the area of ​​the negative electrode extending beyond the positive electrode to at least one side is an overhang region; the edge filler is located in the void region corresponding to the overhang region; the raw material of the edge filler includes a second organic polymer monomer; the positive electrode and / or the negative electrode are the aforementioned battery electrode, or battery electrode prepared by the aforementioned battery electrode preparation method. This solid-state battery cell, through the edge filler filling the void region corresponding to the overhang region, and the combination of the aforementioned battery electrode, or battery electrode prepared by the aforementioned battery electrode preparation method, achieves the coordination of edge filling and internal filling in the solid-state battery cell, which can better avoid cell deformation caused by electrode shrinkage, maintain cell integrity, greatly improve process yield, and provide a basis for the preparation of cells with higher design capacity.

[0088] Specifically, the voids corresponding to the overhang region are filled with edge fillers, including a second organic polymer monomer, forming an edge-locking structure that provides strong support to the overhang region and improves the flatness of the cell edges during manufacturing and use. Furthermore, the presence of the second coating layer increases the density of the active material layer, reducing the compression height of the positive and / or negative electrode sheets in subsequent cell manufacturing processes. In other words, during processing, the presence of the second coating layer results in less height variation of the electrode sheets, while the edge fillers support the overhang region. The combined effect of these two factors reduces the height variation of the cell during processing, thereby improving battery yield.

[0089] (12) In the solid-state battery cell provided by the present invention, the second organic polymer monomer includes a compound with a functionality of >3 acrylate groups. Using the above-mentioned specific monomer raw materials, the second organic polymer formed by the polymerization of the second organic polymer monomer can be further made to have a certain hardness; it does not have fluidity under no stress, avoiding the spread and flattening of the filler material; it has good plasticity under stress, and can creep to better shape and fit and connect the positive and negative electrodes, ensuring edge self-fixation. Furthermore, the second organic polymer monomer includes a compound with a functionality of 4 to 6 acrylate groups, which can control the first organic polymer from being too hard, and achieve a better edge self-fixation effect.

[0090] (13) The method for preparing the above-mentioned solid-state battery cell provided by the present invention includes the following steps: ① mixing a second organic polymer monomer and a second initiator to obtain an edge filler material mixture; ② combining a positive electrode sheet or a negative electrode sheet with a solid electrolyte membrane, then stacking them, and placing the edge filler material mixture into the overhang region; photocuring to obtain a unit cell. In this preparation method, the positive electrode sheet and the negative electrode sheet are stacked first, and then the edge filler material mixture is placed into the overhang region and photocured to obtain a unit cell. During photocuring, in addition to curing the edge filler filling the overhang region, the second coating layer on the surface of the active material particles in the positive electrode sheet and / or the negative electrode sheet can be further cured, further improving the manufacturing efficiency. Attached Figure Description

[0091] Figure 1 This is a schematic flowchart of the solid-state battery cell preparation method provided in Embodiment 1 of the present invention;

[0092] Figure 2 A schematic diagram of the state of the positive electrode active material particles before and after the in-situ crosslinking reaction in step (2) of the solid-state battery cell provided in Embodiment 1 of the present invention;

[0093] Figure 3 This is a physical image of the cell obtained in step (5) of Embodiment 1 of the present invention;

[0094] Figure 4 This is a physical image of the solid-state battery cell provided in Embodiment 1 of the present invention. Figure 4 (a) is a top view. Figure 4 (b) is a side view;

[0095] Figure 5 This is a schematic diagram of the structure of a solid-state battery cell provided in Embodiment 7 of the present invention;

[0096] Figure 6 This is a schematic diagram of a solid-state battery cell provided in Embodiment 7 of the present invention;

[0097] Figure 7 This is a CT scan image of a solid-state battery cell provided in Embodiment 10 of the present invention. Figure 7 (a) is a top view. Figure 7 (b) is a side view;

[0098] Figure 8 This is a micron-level CT scan image of the cross-section of the positive electrode sheet in the solid-state battery cell provided in Embodiment 1 and Comparative Example 1 of the present invention. Figure 8 (a) is Example 1. Figure 8 (b) is Comparative Example 1.

[0099] Wherein, 1-positive electrode sheet; 2-negative electrode sheet; 3-solid electrolyte membrane; 4-edge filler; 11-positive active material layer; 12-positive current collector; 21-negative active material layer; 22-negative current collector; 111-positive active material particles; 112-solid electrolyte particles; 113-second coating layer; 114-first coating layer; 1141-lithium-containing composite oxide; 1142-thiol-terminated silane; 5-unit cell. Detailed Implementation

[0100] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0101] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0102] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0103] Equipment and Instruments

[0104] Mixing equipment: Model AWF-230 fibrillation equipment, manufactured by Xi'an Gaoneng Digital Manufacturing Technology Co., Ltd.; the mixing components are agitator and dispersing disc. In the following text, rotation refers to the agitator speed and dispersing refers to the dispersing disc speed.

[0105] Polytetrafluoroethylene: Juhua JF-4D07, weight average molecular weight 2,000,000~4,000,000.

[0106] Method for detecting the thickness of lithium-containing composite oxide coating on positive or negative electrode active material particles: Refer to GB / T 6462-2005, polish the powder cross-section of the material, and measure it by scanning electron microscopy.

[0107] Example 1

[0108] This embodiment provides a solid-state battery cell and its preparation method, the process flow diagram of which is shown below. Figure 1 As shown, the specific steps include the following:

[0109] Preparation of positive electrode active material layer: by mass parts, take 70 parts of positive electrode active material particles, 20 parts of solid electrolyte particles, 2 parts of conductive agent, 2 parts of binder, and 6 parts of the first organic polymer monomer (hereinafter referred to as the first monomer); take the first initiator and lithium salt, wherein the mass of the first initiator is 0.5% of the mass of the first monomer, and the mass of the lithium salt is 6.4% of the mass of the first monomer.

[0110] LiNi is used as the positive electrode active material particle. 0.9 Co 0.06 Mn 0.04 O2, D50 approximately 8 μm, solid electrolyte particles using Li6PS5Cl, D50 approximately 0.6 μm, conductive agent using carbon nanofibers, binder using polytetrafluoroethylene, first monomer using HDDA (1,6-hexanediol diacrylate), first initiator using DEAP (α,α'-diethoxyacetophenone), lithium salt using LiTFSI (lithium bis(trifluoromethanesulfonyl)imide).

[0111] Preparation of negative electrode active material layer: by mass parts, take 70 parts of negative electrode active material particles, 20 parts of solid electrolyte particles, 2 parts of conductive agent, 2 parts of binder, and 6 parts of first monomer; take the first initiator and lithium salt, wherein the mass of the first initiator is 0.5% of the mass of the first monomer, and the mass of the lithium salt is 6.4% of the mass of the first monomer.

[0112] The negative electrode active material particles are made of silicon-carbon material (Tianmu Pioneer SC3), with a D50 of about 7μm. The solid electrolyte is made of Li6PS5Cl, with a D50 of about 0.6μm. The conductive agent is made of carbon nanofibers. The binder is made of polytetrafluoroethylene. The first monomer is made of HDDA (1,6-hexanediol diacrylate). The first initiator is made of DEAP (α,α'-diethoxyacetophenone). The lithium salt is made of LiTFSI (lithium bis(trifluoromethanesulfonyl)imide).

[0113] (1) Take 70 portions of the above positive electrode active material particles, each with a mass of 200g, and coat them with a Li2ZrO3 layer with a thickness of 10nm using atomic deposition to obtain the first pretreated positive electrode active material particles. The specific coating method is as follows: at 120℃ and 0.5Torr pressure, a volume ratio of 1:1 tetra(dimethylamino)zirconium and H2O vapor is introduced at a flow rate of 250sccm and a pulse time of 0.3s to deposit ZrO2; nitrogen gas is introduced at a flow rate of 35sccm and purged for 6s; a 1:1 ratio of lithium tert-butyloxy and H2O vapor is introduced at a flow rate of 500sccm and a pulse time of 0.2s to deposit a Li2O layer; nitrogen gas is introduced at a flow rate of 35sccm and purged for 7s; the above cycle is repeated 3 times from the introduction of tetra(dimethylamino)zirconium and H2O vapor to the last nitrogen purging to obtain a mixed deposition layer; heat to 450℃ and introduce O2 and Ar at a flow rate of 100sccm. A 1:1 volume ratio of mixed gas was annealed at a constant temperature for 1 hour to form a 10 nm Li2ZrO3 layer; H2O vapor was introduced at a flow rate of 35 sccm and treated for 30 minutes to achieve full hydroxylation of the surface coating.

[0114] The mass of the positive electrode active material particles coated with Li₂ZrO₃ is 203.32g. Therefore, the mass of Li₂ZrO₃ is 203.32g - 200g = 3.32g. a% = 3.32g / 200g × 100% = 1.66%. The molar number of oxygen atoms per mole of Li₂ZrO₃ is 3, n = 3.

[0115] 12.76 g of 3-mercaptopropyltrimethoxysilane was added to the positive electrode active material particles that underwent the first pretreatment. The mixture was stirred in a stirring device at 80 rpm rotation and 1000 rpm dispersion for 20 min to obtain positive electrode active material particles with the first coating layer.

[0116] b% = 12.76g / 200g × 100% = 6.38%.

[0117] (b% / N2) / (n×a% / N1)=(6.38% / 196.34) / (3×1.66% / 153.10)=1.00.

[0118] Take 70 portions of the above-mentioned negative electrode active material particles, each weighing 200g, and coat them with a 10nm thick Li₂ZrO₃ layer using atomic deposition to obtain the first pretreated negative electrode active material particles. The specific coating method is as follows: at 120℃ and 0.5 Torr pressure, a 1:1 volume ratio of tetrakis(dimethylamino)zirconium and H₂O vapor is introduced at a flow rate of 250 sccm with a pulse time of 0.3s to deposit ZrO₂; nitrogen gas is introduced at a flow rate of 35 sccm and purged for 6s; a 1:1 volume ratio of lithium tert-butyloxygenate and H₂O vapor is introduced at a flow rate of 500 sccm with a pulse time of 0.2s to deposit a Li₂O layer; nitrogen gas is introduced at a flow rate of 35 sccm and purged for 7s. This process, from the introduction of tetrakis(dimethylamino)zirconium and H₂O vapor to the final nitrogen purging, constitutes one cycle, which is repeated three times to obtain a mixed deposition layer; then, the mixture is heated to 450℃, and O₂ and Ar are introduced at a flow rate of 100 sccm. A 1:1 volume ratio of mixed gas was annealed at a constant temperature for 1 hour to form a 10 nm Li2ZrO3 layer; H2O vapor was introduced at a flow rate of 35 sccm and treated for 30 minutes to achieve full hydroxylation of the surface coating.

[0119] The mass of the negative electrode active material particles coated with Li₂ZrO₃ is 208.30g. Therefore, the mass of Li₂ZrO₃ is 208.30g - 200g = 8.30g. a% = 8.30g / 200g × 100% = 4.15%. The molar number of oxygen atoms per mole of Li₂ZrO₃ is 3, n = 3.

[0120] In the above-mentioned pretreated negative electrode active material particles, 32.00 g of 3-mercaptopropyltrimethoxysilane was added, and the mixture was stirred at 80 rpm and 1000 rpm for 20 min to obtain negative electrode active material particles with the first coating layer.

[0121] b%=32.00g / 200g×100%=16.00%.

[0122] (b% / N2) / (n×a% / N1)=(16.00% / 196.34) / (3×4.15% / 153.10)=1.0.

[0123] (2) According to the raw materials and amounts used in the preparation of the positive electrode active material layer, the positive electrode active material particles with the first coating layer, the first monomer, the first initiator, the lithium salt, the solid electrolyte particles and the conductive agent are mixed. At 80°C, the mixture is stirred in a stirring device at a rotation speed of 80 rpm and a dispersion speed of 4000 rpm for 40 min to carry out the in-situ crosslinking reaction. Then, the binder is added and the mixture is stirred for another 30 min at the above temperature and speed to carry out fibrillation.

[0124] The positive electrode active material layer is formed by roll-to-roll extrusion to thin it to a thickness of 125 μm.

[0125] A carbon-coated aluminum foil with a thickness of 14 μm was used as the positive electrode current collector. A layer of positive electrode active material was placed on each side of the positive electrode current collector. Hot pressing was carried out at 100℃ and a roll gap of 210 μm. At the same time, the positive electrode sheet with a thickness of 210 μm was obtained by irradiating it with ultraviolet light of 395 nm wavelength for 200 s.

[0126] The following is combined with Figure 2 The state of the positive electrode active material particles before and after the in-situ crosslinking reaction is described.

[0127] Figure 2 The diagram shows the state of the positive electrode active material particles 111 before and after the in-situ crosslinking reaction in step (2) of the solid-state battery cell 5 provided in this embodiment. The state before the crosslinking reaction is shown on the left, and the state after the crosslinking reaction is shown on the right. As can be seen in the left, at least part of the surface of the positive electrode active material particles 111 is tightly coated with a lithium-containing composite oxide 1141, and a terminal mercaptosilane 1142 is connected to the lithium-containing composite oxide 1141. After the crosslinking reaction, the terminal mercaptosilane 1142 achieves a tight connection between the second coating layer 113 and the first coating layer 114, thereby making the second coating layer 113 better coat the positive electrode active material particles 111.

[0128] (3) According to the raw materials and amounts used in the preparation of the negative electrode active material layer, the negative electrode active material particles with the first coating layer, the first monomer, the first initiator, the lithium salt, the solid electrolyte particles and the conductive agent are mixed and stirred at 80°C with a rotation speed of 80 rpm and a dispersion speed of 4000 rpm for 40 min to carry out the in-situ crosslinking reaction. Then, the binder is added and stirred for another 30 min at the above temperature and speed to carry out fibrillation.

[0129] The negative electrode active material layer is formed by roll-to-roll extrusion to thin it to a thickness of 65 μm.

[0130] A carbon-coated copper foil with a thickness of 8 μm was used as the negative electrode current collector. A layer of negative electrode active material was placed on each side of the negative electrode current collector. Hot pressing composite was carried out at 100℃ and a roll gap of 100 μm. At the same time, the negative electrode sheet with a thickness of 100 μm was obtained by irradiating with ultraviolet light of 395 nm wavelength for 200s.

[0131] (4) A solid electrolyte membrane was prepared by wet coating. Sulfide electrolyte membrane Li6PS5Cl and polyisobutylene (weight average molecular weight 1,000,000~3,000,000) were weighed at a mass ratio of 98:2, dissolved in ethyl acetate solvent, and stirred for 2 hours to obtain a slurry with a solid content of 45%. The slurry was coated and dried to obtain a solid electrolyte membrane with a thickness of 40 μm. The solid electrolyte membrane was then transferred onto both sides of the negative electrode sheet by roller pressing to obtain a negative electrode sheet composited with the solid electrolyte membrane.

[0132] (5) Cut a negative electrode sheet with a length × width of 100mm × 100mm and a positive electrode sheet with a length × width of 94mm × 94mm. Both the negative and positive electrode sheets retain inner tabs for subsequent welding. Place one negative electrode sheet with a solid electrolyte membrane at the bottom and one positive electrode sheet at the top, with the solid electrolyte membrane between the negative and positive electrode sheets. Align the centers of the two electrodes and fix them tightly.

[0133] A certain amount of DPHA was used as the second organic polymer monomer (hereinafter referred to as the second monomer), and 3.1% by mass of DEAP was used as the second initiator. DPHA and DEAP were mixed to obtain an edge filler material mixture. The regions on both sides of the negative electrode sheet in the width direction and both sides in the length direction that extend beyond the positive electrode sheet are called overhang regions. The edge filler material mixture was introduced into the overhang region of the negative electrode by stencil printing at a printing speed of 0.1 m / s and a printing thickness of 210 μm, to fill the overhang region in both the length and width directions. The mixture was then irradiated with ultraviolet light at a wavelength of 410 nm for 10 s to cure and form a single cell.

[0134] Take a single battery cell, remove the aluminum-plastic film, and take a picture of the actual product. (See attached image) Figure 3 It can be observed that the edges of its battery cells are flat and there is no collapse, and there is no obvious thickness difference between the edges and the surface.

[0135] (6) Take 5 of the above-mentioned unit cells and stack them from bottom to top with the negative electrode facing down. Place a layer of negative electrode with a solid electrolyte membrane on the top. Perform isostatic pressure treatment at 500MPa for 10 minutes to obtain solid battery cells.

[0136] Take a picture of the solid-state battery cell that has been produced. Figure 4 , Figure 4 (a) is a top view. Figure 4 (b) is a side view; it can be seen that its surface is flat and there is no edge collapse.

[0137] Example 2

[0138] This embodiment provides a solid-state battery cell and its preparation method. Compared with Embodiment 1, the only difference is that in step (1), 11.51g of 3-mercaptopropyltrimethoxysilane is added when preparing the positive electrode active material particles with the first coating layer, b%=11.51g / 200g×100%=5.76%, (b% / N2) / (n×a% / N1)=(5.76% / 196.34) / (3 ×1.66% / 153.10)=0.90; When preparing negative electrode active material particles with the first coating layer, 28.76g of 3-mercaptopropyltrimethoxysilane was added, b%=28.76g / 200g×100%=14.38%, (b% / N2) / (n×a% / N1)=(14.38% / 196.34) / (3×4.15% / 153.10)=0.90.

[0139] Example 3

[0140] This embodiment provides a solid-state battery cell and its preparation method. Compared with Embodiment 1, the only difference is that in step (1), 10.86g of 3-mercaptopropyltrimethoxysilane is added when preparing the positive electrode active material particles with the first coating layer, b%=10.86g / 200g×100%=5.43%, (b% / N2) / (n×a% / N1)=(5.43% / 196.34) / (3 ×1.66% / 153.10)=0.85; When preparing negative electrode active material particles with the first coating layer, 27.15g of 3-mercaptopropyltrimethoxysilane is added, b%=27.15g / 200g×100%=13.58%, (b% / N2) / (n×a% / N1)=(13.58% / 196.34) / (3×4.15% / 153.10)=0.85.

[0141] Example 4

[0142] This embodiment provides a solid-state battery cell and its preparation method. Compared with Embodiment 1, the only difference is that in step (1), 8.95g of 3-mercaptopropyltrimethoxysilane is added when preparing positive electrode active material particles with a first coating layer, b%=8.95g / 200g×100%=4.48%, (b% / N2) / (n×a% / N1)=(4.48% / 196.34) / (3×1.66% / 153.10)=0.70.

[0143] Example 5

[0144] This embodiment provides a solid-state battery cell and its preparation method. Compared with Embodiment 1, the only difference is that in step (1), 22.36g of 3-mercaptopropyltrimethoxysilane is added when preparing negative electrode active material particles with a first coating layer, b%=22.36g / 200g×100%=11.18%, (b% / N2) / (n×a% / N1)=(11.18% / 196.34) / (3×4.15% / 153.10)=0.70.

[0145] Example 6

[0146] This embodiment provides a solid-state battery cell and its preparation method. Compared with Embodiment 1, the only difference is that the first monomer, the first initiator, and the lithium salt are not used in the preparation of the positive electrode active layer; step (1) is omitted; and in step (2), 200g of positive electrode active material particles are used instead of the positive electrode active material particles with the first coating layer used in Embodiment 1. The first monomer, the first initiator, and the lithium salt are omitted, and only the positive electrode active material particles, solid electrolyte particles, and conductive agent are mixed; when the positive electrode sheet is obtained, photocuring is not required.

[0147] Example 7

[0148] This embodiment provides a solid-state battery cell and its preparation method. Compared with Embodiment 1, the only difference is that the first monomer, the first initiator, and the lithium salt are not used in the preparation of the negative electrode active layer; step (1) is omitted; and in step (2), 200g of negative electrode active material particles are used instead of the negative electrode active material particles with the first coating layer used in Embodiment 1. The first monomer, the first initiator, and the lithium salt are omitted, and only the negative electrode active material particles, solid electrolyte particles, and conductive agent are mixed; when the negative electrode sheet is obtained, photocuring is not required.

[0149] The following is combined with Figure 5 , Figure 6 The solid-state battery cell structure prepared in Example 7 is described.

[0150] Figure 5This is a schematic diagram of the structure of the solid-state battery cell 5 provided in this embodiment. The cell 5 provided in this embodiment includes a positive electrode 1, a negative electrode 2, a solid electrolyte membrane 3, and an edge filler 4. The positive electrode 1 and the negative electrode 2 are aligned at their centers and stacked with the negative electrode 2 below and the positive electrode 1 above. The areas on both sides of the negative electrode 2 that extend beyond the positive electrode 1 in the width and length directions are called overhang regions. The edge filler 4 is located in the void area corresponding to the overhang region. The positive electrode 1 includes a positive current collector 12 and positive active material layers 11 located on both sides of the positive current collector 12. The negative electrode 2 includes a negative current collector 22 and negative active material layers 21 located on both sides of the negative current collector 22. The solid electrolyte membrane 3 is located between the negative electrode 2 and the positive electrode 1, and on the side of the negative electrode 2 away from the positive electrode 1. The negative active material layer 21 includes negative active material particles and solid electrolyte particles 112. The positive electrode active material layer 11 includes positive electrode active material particles 111 and solid electrolyte particles 112. At least a portion of the surface of the positive electrode active material particles 111 is coated with a second coating layer 113, and a first coating layer 114 is further included between the positive electrode active material particles 111 and the second coating layer 113. The raw materials of the second coating layer 113 include lithium salt and a first organic polymer monomer, which is beneficial to increasing the conductivity and density of the material. The raw materials of the first coating layer 114 include lithium-containing composite oxide 1141 and mercapto-terminated silane 1142, which can assist the second coating layer 113 in better coating the positive electrode active material particles 111.

[0151] Figure 6 The schematic diagram of the solid-state battery cell provided in this embodiment includes 5 unit cells 5, which are stacked sequentially from bottom to top with the negative electrode 2 located at the bottom, and the topmost layer is a negative electrode 2 with a solid electrolyte film 3 transferred on it.

[0152] Example 8

[0153] This embodiment provides a solid-state battery cell and its preparation method, which differs from Embodiment 2 in that:

[0154] The positive electrode active material layer is prepared as follows: by mass, 60 parts of positive electrode active material particles, 30 parts of solid electrolyte particles, 0.5 parts of conductive agent, 5 parts of binder, and 8 parts of the first monomer are taken; the first initiator and lithium salt are taken, wherein the mass of the first initiator is 5% of the mass of the first monomer, and the mass of the lithium salt is 2% of the mass of the first monomer.

[0155] LiNi is used as the positive electrode active material particle. 0.85 Co 0.1 Mn 0.05O2, D50 is 8μm, solid electrolyte particles are Li6PS5Cl, D50 is 0.76μm, conductive agent is acetylene black, binder is polytetrafluoroethylene, first monomer is PETA (pentaerythritol triacrylate), first initiator is HCPK (1-hydroxy-cyclohexyl benzophenone), lithium salt is lithium bisfluorosulfonylimide (LiFSI).

[0156] The negative electrode active material layer is prepared as follows: by mass, 85 parts of negative electrode active material particles, 5 parts of solid electrolyte particles, 2 parts of conductive agent, 0.5 parts of binder, and 2 parts of the first monomer are taken; the first initiator and lithium salt are taken, wherein the mass of the first initiator is 3% of the mass of the first monomer, and the mass of the lithium salt is 10% of the mass of the first monomer.

[0157] The negative electrode active material particles are made of pure silicon (Tianmu Pioneer) with a D50 of 5μm. The second solid electrolyte is made of Li6PS5Cl with a D50 of 0.4μm. The conductive agent is acetylene black, the binder is polytetrafluoroethylene, the first monomer is PETA (pentaerythritol triacrylate), the first initiator is HCPK (1-hydroxy-cyclohexyl benzophenone), and the lithium salt is lithium bisfluorosulfonylimide (LiFSI).

[0158] Step (1) involves taking 60 portions of the above-mentioned positive electrode active material particles, each weighing 170g, and coating them with a 2nm thick Li2TiO3 layer using atomic deposition to obtain the first pretreated positive electrode active material particles. The specific coating method is the same as in Example 1, using TiCl4 as the Ti source, and cycling once to obtain 2nm Li2TiO3.

[0159] The mass of the positive electrode active material particles coated with Li₂TiO₃ is 170.49g. Therefore, the mass of Li₂TiO₃ is 170.49g - 170g = 0.49g. a% = 0.49g / 170g × 100% = 0.29%. The molar number of oxygen atoms per mole of Li₂TiO₃ is 3, n = 3.

[0160] Add 3.18g of γ-mercaptopropyltriethoxysilane to the above-mentioned pretreated positive electrode active material particles, and stir at 80 rpm rotation and 1000 rpm dispersion for 20 min to obtain positive electrode active material particles with the first coating layer.

[0161] b% = 3.18g / 170g × 100% = 1.87%.

[0162] (b% / N2) / (n×a% / N1)=(1.87% / 238.42) / (3×0.29% / 109.75)=1.00.

[0163] Take 85 portions of the above-mentioned negative electrode active material particles, each weighing 240g, and coat them with a 2nm thick LiTaO3 using atomic deposition to obtain the first pretreated negative electrode active material particles. The specific coating method is the same as in Example 1, with TaO2 as the Ta source, and one cycle to obtain 2nm LiTaO3.

[0164] The mass of the negative electrode active material particles coated with LiTaO3 is 241.94g. Therefore, the mass of LiTaO3 is 241.94g - 240g = 1.94g. a% = 1.94g / 240g × 100% = 0.81%. The molar number of oxygen atoms per mole of LiTaO3 is 3, n = 3.

[0165] In the above-mentioned pretreated negative electrode active material particles, 4.84 g of 3-mercaptopropyltrimethoxysilane was added, and the mixture was stirred at 80 rpm and 1000 rpm for 20 min to obtain negative electrode active material particles with the first coating layer.

[0166] b% = 4.84g / 240g × 100% = 2.02%.

[0167] (b% / N2) / (n×a% / N1)=(2.02% / 196.34) / (3×0.81% / 235.89)=1.00.

[0168] In step (5), the length × width of the positive electrode is 90mm × 90mm, the mass of the second initiator is 0.5% of the second monomer, the second monomer is DPHA (dipentaerythritol hexaacrylate), and the second initiator is HHMP (2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl-1-propanone).

[0169] Example 9

[0170] This embodiment provides a solid-state battery cell and its preparation method, which differs from Embodiment 2 in that:

[0171] The positive electrode active material layer is prepared as follows: by mass, 85 parts of positive electrode active material particles, 5 parts of solid electrolyte particles, 0.5 parts of conductive agent, 5 parts of binder, and 2 parts of the first monomer are taken; the first initiator and lithium salt are taken, wherein the mass of the first initiator is 3% of the mass of the first monomer, and the mass of the lithium salt is 10% of the mass of the first monomer.

[0172] LiNi is used as the positive electrode active material particle. 0.8 Co 0.15 Mn 0.05O2, D50 is 6.5μm, solid electrolyte particles are Li6PS5Cl, D50 is 0.5μm, conductive agent is Ketjen Black, binder is polytetrafluoroethylene, first monomer is TMPTA (trimethylolpropane triacrylate), first initiator is HCPK (1-hydroxycyclohexyl benzophenone), lithium salt is lithium difluoroborate oxalate (LiDFOB).

[0173] The negative electrode active material layer is prepared as follows: by mass, 60 parts of negative electrode active material particles, 30 parts of solid electrolyte particles, 0.5 parts of conductive agent, 5 parts of binder, and 8 parts of the first monomer are taken; the first initiator and lithium salt are taken, wherein the mass of the first initiator is 5% of the mass of the first monomer, and the mass of the lithium salt is 2% of the mass of the first monomer.

[0174] The negative electrode active material particles are made of pure silicon with a D50 of 1 μm. The second solid electrolyte is made of Li6PS5Cl with a D50 of 0.4 μm. The conductive agent is Ketjen Black, the binder is polytetrafluoroethylene, the first monomer is TMPTA (trimethylolpropane triacrylate), the first initiator is HCPK (1-hydroxycyclohexyl benzophenone), and the lithium salt is lithium difluoroborate oxalate (LiDFOB).

[0175] Step (1) involves taking 85 portions of the above-mentioned positive electrode active material particles, each weighing 240g, and coating them with a 30nm thick LiAlO2 layer using atomic deposition to obtain the first pretreated positive electrode active material particles. The specific coating method is the same as in Example 1, with Al2O3 selected as the Ti source, and 30nm LiAlO2 obtained by 10 cycles.

[0176] The mass of the positive electrode active material particles coated with LiAlO2 is 247.5g. Therefore, the mass of Li2TiO3 is 247.5g - 240g = 7.5g. a% = 7.5g / 240g × 100% = 3.13%. The molar number of oxygen atoms per mole of LiAlO2 is 2, n = 2.

[0177] Add 44.68 g of 3-mercaptopropyltrimethoxysilane to the pretreated positive electrode active material particles and stir at 80 rpm and 1000 rpm for 20 min to obtain positive electrode active material particles with the first coating layer.

[0178] b%=44.68g / 240g×100%=18.62%.

[0179] (b% / N2) / (n×a% / N1)=(18.62% / 196.34) / (2×3.13% / 65.92)=1.00.

[0180] Take 170g of the above-mentioned 60 negative electrode active material particles and coat them with a 30nm thick LiTaO3 using atomic deposition to obtain the first pretreated negative electrode active material particles. The specific coating method is the same as in Example 1, with TaO2 as the Ta source, and the process is repeated 10 times to obtain 30nm LiTaO3.

[0181] The mass of the negative electrode active material particles coated with LiTaO3 is 190.66g. Therefore, the mass of LiTaO3 is 190.66g - 170g = 20.66g. a% = 20.66g / 170g × 100% = 12.15%. The molar number of oxygen atoms per mole of LiTaO3 is 3, n = 3.

[0182] In the above-mentioned pretreated negative electrode active material particles, 47.48g of γ-mercaptopropylmethyldimethoxysilane was added, and the mixture was stirred at 80 rpm and 1000 rpm for 20 min to obtain negative electrode active material particles with the first coating layer.

[0183] b%=47.48g / 170g×100%=27.93%.

[0184] (b% / N2) / (n×a% / N1)=(27.93% / 180.34) / (3×12.15% / 235.89)=1.00.

[0185] In step (6), the length × width of the positive electrode is 96mm × 96mm, the mass of the second initiator is 5% of the second monomer, the second monomer is PETTA (pentaerythritol tetraacrylate), and the second initiator is DEAP (α, α'-diethoxyacetophenone).

[0186] Example 10

[0187] This embodiment provides a solid-state battery cell and its preparation method. Compared with embodiment 1, the only difference is that in step (7), 9 of the above-mentioned unit cells are used instead of 5 of the above-mentioned unit cells, and the stacking method is the same as in embodiment 1.

[0188] Comparative Example 1

[0189] This comparative example provides a solid-state battery cell and its preparation method, including the following steps:

[0190] (1) Take LiNi in a mass ratio of 70:25:2:3 0.9 Co 0.06 Mn 0.04O2, sulfide electrolyte (Li6PS5Cl), conductive agent (carbon fiber), and binder (polystyrene) are thoroughly stirred in an organic solvent (paraxylene) to obtain a slurry with a solid content of 45%. The slurry is coated on both sides of a carbon-coated aluminum foil (14 μm thick), and the solvent is dried at 70°C to obtain a positive electrode sheet with a thickness of 210 μm.

[0191] (2) Take silicon carbide material (Tianmu Pioneer SC3, D50 about 7μm), sulfide electrolyte (Li6PS5Cl), conductive agent (carbon fiber) and binder (polystyrene) in a mass ratio of 75:20:2:3, stir them thoroughly in an organic solvent (paraxylene) to obtain a slurry with a solid content of 47%, coat both sides of the slurry onto the carbon-coated copper foil (thickness 10μm), dry the solvent at 70℃ to obtain a negative electrode sheet with a thickness of 100μm.

[0192] (3) A solid electrolyte membrane was prepared by wet coating. Sulfide electrolyte membrane Li6PS5Cl and polyisobutylene (weight average molecular weight 1,000,000~4,000,000) were weighed at a mass ratio of 98:2, dissolved in ethyl acetate solvent, and stirred for 2 hours to obtain a slurry with a solid content of 47%. The slurry was coated and dried to obtain a solid electrolyte membrane with a thickness of 40 μm. The solid electrolyte membrane was then transferred onto both sides of the negative electrode sheet by roller pressing to obtain a negative electrode sheet with a solid electrolyte membrane.

[0193] (4) Cut a negative electrode sheet with a length and width of 100mm × 100mm and a positive electrode sheet with a length and width of 94mm × 94mm. Take a negative electrode sheet with a solid electrolyte membrane at the bottom, and stack 5 positive electrode sheets and 6 negative electrode sheets in sequence with 1 negative electrode sheet with a solid electrolyte membrane and 1 positive electrode sheet, so that their centers are aligned; perform isostatic pressing to obtain a solid battery cell.

[0194] Comparative Example 2

[0195] This comparative example provides a solid-state battery cell and its preparation method. Compared with Comparative Example 1, the only difference is that in step (4), 9 positive electrode plates and 10 negative electrode plates are stacked in sequence, and the stacking method is the same as that of Comparative Example 1.

[0196] Comparative Example 3

[0197] This comparative example provides a solid-state battery cell and its preparation method. The only difference from Example 6 is that 3-mercaptopropyltrimethoxysilane is not added in the first pretreatment step of the negative electrode active material particles in step (1).

[0198] Comparative Example 4

[0199] This comparative example provides a solid-state battery cell and its preparation method. Compared with Example 6, the only difference is that in the first pretreatment of the negative electrode active material particles in step (1), polydimethylsiloxane (PDMS) is used to replace 3-mercaptopropyltrimethoxysilane by mass.

[0200] Comparative Example 5

[0201] This comparative example provides a solid-state battery cell and its preparation method. Compared with Example 6, the only difference is that the first monomer, the first initiator, and the lithium salt are not used in the preparation of the negative electrode active layer; the first monomer, the first initiator, and the lithium salt are not added in step (3); that is, the second coating layer is not prepared.

[0202] Comparative Example 6

[0203] This comparative example provides a solid-state battery cell and its preparation method. Compared with Example 6, the only difference is that the first monomer and the first initiator are not used in the preparation of the negative electrode active layer; and the first monomer and the first initiator are not added in step (3).

[0204] Comparative Example 7

[0205] This comparative example provides a solid-state battery cell and its preparation method. Compared with Example 6, the only difference is that lithium salt is not used in the preparation of the negative electrode active layer; lithium salt is not added in step (3); that is, the second coating layer obtained does not contain lithium salt.

[0206] Comparative Example 8

[0207] This comparative example provides a solid-state battery cell and its preparation method. Compared with Example 6, the only difference is that in step (1), lithium-containing composite oxide is not coated on the surface of the negative electrode active material particles. Instead, the negative electrode active material particles are mixed with 3-mercaptopropyltrimethoxysilane and stirred to form negative electrode active material particles with a first coating layer.

[0208] Experimental Example 1

[0209] A CT scan was performed on the solid-state battery cell prepared in Example 10; the resulting images are shown below. Figure 7 ,in Figure 7 (a) is a top view. Figure 7 (b) is a side view.

[0210] from Figure 7 As can be seen in (a), in the top view, the solid-state battery cell prepared in Example 10 has a flat surface without cracks. The apparent edge depression is due to the low density of the edge filler, which cannot be displayed in the CT image. Figure 7As can be seen in (b), in the side view, the negative electrode in the overhang area of ​​the cell is supported by the edge filler and is at the same height as the core (the filler is shown in black). In addition, no obvious solid electrolyte membrane rupture caused by edge collapse was observed, indicating that the edge filler plays a key role in preventing edge collapse.

[0211] Experiment Example 2

[0212] The positive electrode sheet from the solid-state battery cell prepared in Example 1 and Comparative Example 1 was cut out and subjected to micron-level CT scanning. The resulting images are shown in [images not provided]. Figure 8 . Figure 8 (a) is a cross-sectional CT scan image of the positive electrode sheet in Example 1, wherein the left image has lower contrast and the right image has higher contrast; Figure 8 (b) is a cross-sectional CT scan image of the positive electrode in Comparative Example 1, in which the left image has lower contrast and the right image has higher contrast; in the image with higher contrast, the black pores in the electrode can be seen more clearly.

[0213] from Figure 8 As can be seen in (a), the positive electrode sheet prepared in Example 1 has solid particles in close contact within the active material layer, with a density of up to 97% according to statistical data; from Figure 8 As can be seen in (b), the positive electrode sheet prepared in Comparative Example 1 shows obvious pores in the solid particles within the active material layer, with a density of approximately 90% according to statistical data. In the solid-state battery cell provided by the present invention, the coating of the active material particles with a first coating layer and a second coating layer plays a key role in optimizing the solid-solid contact.

[0214] Experimental Example 3

[0215] Solid-state battery cells prepared in the examples and comparative examples were packaged, and tabs were welded on. The tab size was 25×45mm. The cells were then fully sealed to obtain an all-solid-state battery. The battery's electrical performance was tested at 30°C.

[0216] (1) Capacity utilization: Connect the test equipment under 30MPa pressure, charge at 0.1C constant current to 4.25V, switch to 4.25V constant voltage charging to 0.02C current; after standing for half an hour, discharge at 0.1C constant current to 2.5V, cycle 3 times, and take the average discharge capacity.

[0217] (2) Battery internal resistance: When connected to an electrochemical workstation at a pressure of 30 MPa, the resistance is between 0.01 and 10 MPa. 5 Tests were conducted at a sweep rate of 5mV within the Hz range.

[0218] (3) Capacity retention rate of 1C / 0.1C discharge: Connect the test equipment under 30MPa pressure, charge at 0.1C constant current to 4.25V, then switch to 4.25V constant voltage charging to 0.02C current; discharge at 0.1C constant current to 2.5V, record the discharge capacity at 0.1C as Q0; after standing for 1 hour, charge at 1C constant current to 4.25V, then switch to 4.25V constant voltage charging to 0.02C current; discharge at 0.1C constant current to 2.5V, record the discharge capacity at 0.1C as Q1; calculate the capacity retention rate of 1C / 0.1C discharge = Q1 / Q0 × 100%.

[0219] (4) 100-cycle capacity retention rate: The battery capacity retention rate was tested under charge / discharge cutoff voltage of 2.5~4.25V and current density of 0.33C. Cycle capacity retention rate = discharge capacity of the 100th cycle / discharge capacity of the first cycle × 100%.

[0220] (5) Manufacturing yield: For each example and comparative example, 30 parallel samples of the corresponding solid-state battery cell were prepared. All solid-state batteries were prepared according to the above method and tested for short circuit. In each group of parallel samples, the number of short-circuited solid-state batteries was counted as W1, and the manufacturing yield was (30-W1) / 30×100%.

[0221] The test method for whether there is a short circuit is as follows: Connect the all-solid-state battery to the test equipment (Newway CE-500 electrical performance test channel), test the voltage, apply a pressure of 30MPa in the thickness direction of the solid-state battery cell, let it stand, and observe whether there is a voltage drop before and after the pressure is applied. If there is a voltage drop greater than 30mV, it is considered a short circuit.

[0222] The test results are shown in Table 1.

[0223] Table 1

[0224]

[0225] As shown in Table 1, the solid-state battery cells provided in this application all exhibit excellent capacity utilization, high rate discharge capacity retention, high cycle capacity retention, low manufacturing yield, and low internal resistance. The solid-state battery cells provided in this application are beneficial for maximizing the designed battery capacity and can deliver good long-term cycle stability and rate performance. The solid-state battery cells obtained in the comparative examples have poor performance, and due to the extremely low manufacturing yield in Comparative Example 2, no further testing of other electrical properties was conducted for safety reasons.

[0226] Experiment Example 4

[0227] The solid-state battery cells prepared in Example 1, Comparative Examples 1 and 5 were used to test their safety performance.

[0228] (1) Oxygen release temperature and enthalpy of oxygen release by DSC (differential scanning calorimetry) of positive electrode: Take 2~10mg of the fully charged (100% SOC) positive electrode from Example 1, Comparative Examples 1 and 5 respectively, and place the sample in the DSC crucible; under N2 atmosphere, the heating rate is 5-10℃ / min, and the test is carried out to 300℃. The DSC curve is recorded and analyzed.

[0229] (2) Hot box test: Charge the solid-state battery cells to 100% SOC, place them in the hot box with clamps, monitor the cell voltage and temperature, raise the hot box to 130℃ and keep it warm for 30 minutes; if the cell does not catch fire or explode, continue to raise the temperature by 10℃ and keep it warm for 30 minutes until the cell catches fire and explodes, and record the temperature at the time of thermal runaway.

[0230] The results are shown in Table 2.

[0231] Table 2

[0232]

[0233] As can be seen from Table 2, the solid-state battery cell provided in this application has a high DSC oxygen release temperature and hot box test temperature of the positive electrode, and a significantly lower DSC oxygen release enthalpy of the positive electrode, which has excellent thermal safety performance.

[0234] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A battery electrode, characterized in that, Includes a current collector, and an active material layer located on at least one side of the current collector, wherein the active material layer includes active material particles; The active material particles are at least partially coated with a first coating layer, and at least partially coated with a second coating layer; the raw materials of the first coating layer include lithium-containing composite oxide and thiol-terminated silane; the raw materials of the second coating layer include lithium salt and a first organic polymer monomer; The lithium-containing composite oxide includes at least one of Li2ZrO3, Li2TiO3, LiTaO3, and LiAlO2; The terminal mercapto silanes include at least one of 3-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane. The lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium dioxaborate, lithium difluoroborate, and lithium tetrafluoroborate. The first organic polymer monomer comprises a compound having a functionality of 1 to 3 acrylate groups; The first coating layer satisfies the following relationship: 0.7≤ ≤1； Wherein, a% is the percentage of the mass of the lithium-containing composite oxide to the mass of the active material particles when the first coating layer is prepared; b% is the percentage of the mass of the terminal thiol silane to the mass of the active material particles during the preparation of the first coating layer; n is the molar number of oxygen atoms per mole of the lithium-containing composite oxide; N1 is the molar mass of the lithium-containing composite oxide used in the preparation of the first coating layer, in g / mol; N2 represents the molar mass of the terminal thiol silane used in preparing the first coating layer, expressed in g / mol.

2. The battery electrode according to claim 1, characterized in that, The battery electrode sheet satisfies at least one of the following conditions: (1) In the raw materials of the second coating layer, the mass ratio of the first organic polymer monomer to the active material particles is 2~8:60~85; (2) In the raw materials of the second coating layer, the mass of lithium salt is 2% to 10% of the mass of the first organic polymer monomer; (3) The active material layer also includes solid electrolyte particles; (4) The active material particles include positive electrode active material particles or negative electrode active material particles; (5) The active material layer also includes a conductive agent and a binder.

3. The battery electrode according to claim 2, characterized in that, The first coating layer satisfies the following relationship: 0.85≤ ≤1； And / or, 0.2% ≤ a% ≤ 13%; And / or, 1% ≤ b% ≤ 32%; And / or, 2≤n≤4; And / or, 60≤N1≤250; And / or, 100≤N²≤500; And / or, in the active material layer, the mass ratio of the solid electrolyte particles to the active material particles is 5~30:60~85; And / or, the solid electrolyte particles include at least one of sulfide solid electrolyte particles, oxide solid electrolyte particles, and halide solid electrolyte particles; And / or, the first organic polymer monomer includes at least one of isoborneol acrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, pentaerythritol triacrylate, and trimethylolpropane triacrylate. And / or, the positive electrode active material particles include at least one of nickel-cobalt-manganese ternary materials, nickel-iron-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium iron phosphate materials, and lithium manganese oxide materials; And / or, the negative electrode active material particles include at least one of silicon-based materials and carbon-based materials.

4. A method for preparing a battery electrode sheet as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1: Coating the surface of the active material particles with a lithium-containing composite oxide to obtain the first pretreated active material particles; S2: Mix the pretreated active material particles with terminal thiol silane to obtain active material particles with a first coating layer; S3: Mix the active material particles with the first coating layer, the first organic polymer monomer, the first initiator, and the lithium salt, and perform a cross-linking reaction to obtain an active material mixture. Press the mixture to obtain an active material layer. S4: The active material layer is composited onto the current collector and photocured to obtain the battery electrode.

5. The method for preparing battery electrode sheets according to claim 4, characterized in that, The mass of the first initiator is 0.5% to 5% of the mass of the first organic polymer monomer; And / or, the first initiator comprises at least one of α,α'-dimethylbenzoyl ketal, α,α'-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxy-cyclohexylbenzophenone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl-1-propanone, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; And / or, in S4, the photocuring time is 5~600s, and the ultraviolet irradiation wavelength used for photocuring is 395~410nm; And / or, in S3, the crosslinking reaction time is 30~50 min and the temperature is 50~100℃; And / or, in S1, the coating method includes atomic deposition; And / or, in S3, solid electrolyte particles are added before pressing; And / or, in step S3, a conductive agent and a binder are added before pressing.

6. A solid-state battery cell, characterized in that, This includes battery electrode sheets as described in any one of claims 1 to 3, or battery electrode sheets prepared by the method described in claim 4 or 5.

7. The solid-state battery cell according to claim 6, characterized in that, It includes at least one unit cell, the unit cell comprising a positive electrode, a negative electrode, a solid electrolyte membrane, and edge filler; The positive electrode, solid electrolyte membrane, and negative electrode are stacked together, and the area around the negative electrode that extends beyond the positive electrode to at least one side is the overhang region. The edge filler is located in the void area corresponding to the overhang region; The raw material for the edge filler includes a second organic polymer monomer; The positive electrode and / or negative electrode are battery electrodes as described in any one of claims 1 to 3, or battery electrodes prepared by the method described in claim 4 or 5.

8. The solid-state battery cell according to claim 7, characterized in that, The second organic polymer monomer includes compounds with a functionality of more than 3 acrylate groups; And / or, in each cell unit, the solid electrolyte membrane is located between the negative electrode and the positive electrode, and on the side of the negative electrode away from the positive electrode; or, in each cell unit, the solid electrolyte membrane is located between the negative electrode and the positive electrode, and on the side of the positive electrode away from the negative electrode. And / or, the width of one side of the overhang region is 2~5mm.

9. The solid-state battery cell according to claim 8, characterized in that, The second organic polymer monomer includes at least one of pentaerythritol hexaacrylate and pentaerythritol tetraacrylate; And / or, the second organic polymer monomer comprises a compound having a functionality of 4 to 6 acrylate groups.

10. A method for preparing a solid-state battery cell as described in any one of claims 7 to 9, characterized in that, Includes the following steps: ① The second organic polymer monomer and the second initiator are mixed to obtain a mixture of edge filler raw materials; ② The positive or negative electrode sheet is combined with a solid electrolyte membrane and then stacked. An edge filler material mixture is placed into the overhang region; photocuring is performed to obtain a unit cell.

11. The preparation method according to claim 10, characterized in that, The mass of the second initiator is 0.5% to 5% of the mass of the second organic polymer monomer; And / or, the second initiator comprises at least one of α,α'-dimethylbenzoyl ketal, α,α'-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxy-cyclohexylbenzophenone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl-1-propanone, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; And / or, in step ②, the photocuring time is 10~60s, and the ultraviolet irradiation wavelength used for photocuring is 395~410nm; And / or, after step ②, the method further includes a step of stacking several unit cells.

12. A solid-state battery, characterized in that, This includes battery electrode sheets as described in any one of claims 1 to 3, or battery electrode sheets prepared by the method described in claim 4 or 5, or solid-state battery cells as described in any one of claims 6 to 9, or solid-state battery cells prepared by the method described in claim 10 or 11.

13. An electrical appliance, characterized in that, Includes the solid-state battery as described in claim 12, wherein the solid-state battery serves as the power supply for the electrical device.

Images