Battery pole piece, preparation method of battery pole piece and solid-state battery

Abstract

The embodiment of the application provides a battery pole piece, a battery pole piece preparation method and a solid-state battery. The battery pole piece is prepared from a mixture of an active material, a solid-state electrolyte, a conductive agent and a binder. The mass ratio of the active material, the solid-state electrolyte, the conductive agent and the binder is 60-90:10-30:0.5-3:0.5-5. A higher proportion of the active material can significantly improve the energy density of the battery, and is fully mixed with the conductive agent, the solid-state electrolyte and the binder, which helps to uniformly distribute the current on the pole piece. The solid-state electrolyte is more stable in a high-temperature environment, which increases the overall safety of the battery. The appropriate conductive agent can improve the electron conduction between the active materials, significantly reduce the resistance, and ensure that the pole piece as a whole has good conductivity. The appropriate binder helps to maintain the integrity of the internal structure of the pole piece. The application solves the technical problems of large battery impedance and low battery safety performance.

Description

Technical Field

[0001] This application relates to the technical field of battery electrodes, specifically to a battery electrode, a method for preparing the battery electrode, and a solid-state battery. Background Technology

[0002] In existing technologies, methods for controlling the thinning area of ​​lithium-ion batteries mostly employ wet coating processes. Since most solid electrolytes are sensitive to water or polar solvents, they are prone to decomposition or side reactions, leading to a sharp decline in electrochemical performance. Furthermore, solvent residues can compromise the stability of the solid-state interface. During the bonding process between the solid electrolyte and the active material, the high hardness and difficulty in breaking the solid electrolyte make it difficult to achieve effective and uniform mixing and bonding with the active material, affecting the chemical performance of the solid-state battery and consequently resulting in high battery impedance and low battery safety.

[0003] There is currently no good solution to the above problems. Summary of the Invention

[0004] This application provides a battery electrode, a method for preparing the battery electrode, and a solid-state battery to at least solve the technical problems of high battery impedance and low battery safety performance.

[0005] According to one aspect of the embodiments of this application, a battery electrode is provided, which is prepared from a mixture of active material, solid electrolyte, conductive agent and binder, wherein the mass ratio of active material, solid electrolyte, conductive agent and binder is 60~90:10~30:0.5~3:0.5~5.

[0006] Furthermore, the active material includes NCM811, the solid electrolyte includes Li6PS5Cl, the conductive agent includes VGCF, and the binder includes PTFE.

[0007] According to another aspect of the embodiments of this application, a method for preparing a battery electrode is provided, comprising: step S1, mixing an active material, a conductive agent, a binder, and a solid electrolyte uniformly to obtain a mixture; step S2, fiberizing the mixture; step S3, extruding the fiberized mixture to obtain an initial self-supporting film, and thinning the initial self-supporting film using a roll forming process; step S4, cutting off the edge region of the thinned initial self-supporting film to obtain a target self-supporting film; and step S5, thermally bonding and winding the target self-supporting film with a foil using a thermal bonding process to obtain a battery electrode.

[0008] Further, in step S4, the width of the cut edge region is L, where 10mm≤L≤20mm.

[0009] Further, in step S5, the target self-supporting film and foil are thermally laminated and wound together by a thermal lamination process to obtain a battery electrode sheet, including the following steps: step S52, cutting the target self-supporting film into multiple sub-films; step S53, thermally laminating and winding the multiple sub-films and foil together by a thermal lamination process to obtain a battery electrode sheet with multiple spaced regions.

[0010] Further, in step S2, the mixture is fiberized, including the following steps: Step S21, the mixture is sheared at a first preset speed until the temperature of the mixture is a first preset temperature, and the mixture is sheared at the first preset temperature and the first preset speed for a first preset time to fiberize the binder, wherein the first preset speed is 3000 rpm, the first preset temperature is 80°C, and the first preset time is 1~2h.

[0011] Further, in step S3, the fiberized mixture is extruded to obtain an initial self-supporting film, and the initial self-supporting film is thinned by a rolling process, including the following steps: Step S31, the fiberized mixture is transferred to the feeding unit, and the initial self-supporting film is obtained by extrusion through the feeding unit; Step S32, the rolling unit is controlled to roll the initial self-supporting film with a first preset pressure and a second preset temperature until the thickness of the initial self-supporting film meets the preset thickness, and the thinned initial self-supporting film is obtained, wherein the first preset pressure is 20T, the second preset temperature is 100℃, and the thinned initial self-supporting film has a preset thickness H, 125μm≤H≤150μm.

[0012] Further, in step S3, the initial self-supporting film is thinned by a rolling process, including the following steps: Step S33, the initial self-supporting film is rolled sequentially by multiple sub-rolling units of the rolling unit to thin the initial self-supporting film, wherein the gap between the multiple sub-rolling units is set to decrease sequentially.

[0013] Further, in step S1, the active material, conductive agent, binder, and solid electrolyte are mixed evenly to obtain a mixture, including the following steps: Step S11, at a preset dew point temperature, the active material, solid electrolyte, conductive agent, and binder are added to a mixer according to a preset mass ratio, the mixing temperature of the mixer is controlled at a third preset temperature, and the mixture is mixed evenly at a second preset speed for a second preset time to obtain a mixture, wherein the preset dew point temperature is less than -60℃, the third preset temperature is less than 18℃, the second preset speed is 1000 rpm, and the second preset time is 20 min.

[0014] According to another aspect of the embodiments of this application, a solid-state battery is provided, including a battery electrode, wherein the battery electrode is the battery electrode described above, or the battery electrode is prepared by the battery electrode preparation method described above.

[0015] The technical solution of this application embodiment is used to prepare battery electrodes by mixing active materials, solid electrolytes, conductive agents, and binders. The active materials comprise 75% of the material; a higher proportion of active materials significantly improves the battery's energy density, allowing it to store more energy. Furthermore, thorough mixing with the conductive agents, solid electrolytes, and binders helps ensure uniform current distribution on the electrode. The solid electrolyte comprises 18% of the material; it is non-flammable, non-explosive, and more stable at high temperatures, ensuring lithium-ion conductivity while also enhancing overall battery safety. The conductive agent comprises 2% of the material; it improves electronic conduction between active materials, significantly reducing resistance and ensuring good overall conductivity of the electrode. The binder comprises 5% of the material; an appropriate binder helps maintain the integrity of the electrode's internal structure. Through suitable material ratios, the safety, conductivity, and mechanical stability of the battery electrodes are improved. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 This is a schematic diagram of a solid-state battery electrode preparation method according to an embodiment of this application;

[0018] Figure 2 This is a diagram illustrating an optional step in thinning an initial self-supporting membrane according to an embodiment of this application;

[0019] Figure 3 This is a diagram illustrating an optional step in thermally bonding and winding a target self-supporting film with a foil, according to an embodiment of this application.

[0020] Figure 4 This is a schematic diagram of the composition of an optional electrode preparation apparatus according to an embodiment of this application;

[0021] Figure 5 This is a top view of an optional dry continuous electrode according to an embodiment of this application;

[0022] Figure 6 This is a schematic diagram of the composition of an optional electrode preparation apparatus according to an embodiment of this application;

[0023] Figure 7 This is a top view of an optional dry discontinuous electrode according to an embodiment of this application.

[0024] The above figures include the following reference numerals:

[0025] 1. Feeding unit; 2. Roll forming unit; 3. Foil unwinding unit; 4. Edge trimming unit; 5. Thermal lamination unit; 6. Cutting unit; 7. Foil; 8. Active material layer. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0030] In the production of solid-state batteries, the general production method involves stacking positive electrode sheets, a solid electrolyte layer, and negative electrode sheets. Due to the solid-solid interface of the solid electrolyte, it needs to be in close contact with the positive and negative electrode sheets to ensure smooth lithium-ion transport and reduce internal resistance. However, during the coating process of the positive and negative electrodes, in order to prevent problems such as local overpressure, wavy edges, and edge material loss caused by thickness differences between the coating area and the empty foil area during the rolling process, the edges of the positive and negative electrodes are usually thinned in the coating direction. The thinning of the edges of the positive and negative electrode sheets will prevent the middle solid electrolyte layer from making close contact with the electrode sheets, increasing the difficulty of lithium-ion transport, increasing battery impedance, and thus affecting cell performance.

[0031] In actual production, after the stacking is completed, the assembled electrode core is pressurized. However, this pressurization only applies to the flat central area, and the thinned areas on both sides cannot be bonded. As a result, a uniformly bonded solid electrolyte-electrode interface cannot be obtained, leading to uneven current and resistance, which affects the cell performance. Furthermore, after the cell is assembled, the thinning problem at the head of the cell can easily cause uneven cell thickness, which affects the assembly.

[0032] The wet coating process for electrodes is limited by the flow characteristics of the slurry itself. At the edges and beginning / end areas after coating, the slurry thickness may be less than that of the main coated area; these edge areas are called "thinning zones." The presence of thinning zones not only leads to an imbalance in the N / P ratio at the electrode coating edges, but also causes wavy edges on the electrodes during subsequent hot pressing due to inconsistent electrode thickness. Both N / P ratio imbalance and wavy edges can lead to abnormal lithium plating during battery use, severely reducing battery safety performance.

[0033] The common methods for controlling the thinning area of ​​lithium-ion batteries currently include the following:

[0034] 1) Increasing the viscosity of the slurry can reduce its flow characteristics, but increasing the viscosity of the slurry can easily lead to problems such as uneven electrode coating, slurry clogging of the nozzle, and slurry agglomeration.

[0035] 2) The flow of slurry is controlled by a gasket at the coating edge, which can easily cause eddies to form at the contact point between the slurry and the gasket, resulting in abnormal conditions such as "V-angle" at the edge.

[0036] 3) By attaching tape to the foil before coating, and then heating it after coating and drying to remove the tape from the thinned area of ​​the electrode, the residual adhesive on the foil surface after removing the tape will affect the welding.

[0037] 4) The electrode thinning area is removed by laser treatment. However, this method has low efficiency in removing the thinned area by laser and may cause damage to the foil and material area.

[0038] Combination Figures 1 to 7As shown, embodiments of this application provide a battery electrode and a method for preparing the battery electrode.

[0039] Specifically, the battery electrode is made of a mixture of active material, solid electrolyte, conductive agent and binder, wherein the mass ratio of active material, solid electrolyte, conductive agent and binder is 60~90:10~30:0.5~3:0.5~5.

[0040] The technical solution of this application embodiment is used to prepare battery electrodes by mixing active materials, solid electrolytes, conductive agents, and binders. The active materials comprise 75% of the material; a higher proportion of active materials significantly improves the battery's energy density, allowing it to store more energy. Furthermore, thorough mixing with the conductive agents, solid electrolytes, and binders helps ensure uniform current distribution on the electrode. The solid electrolyte comprises 18% of the material; it is non-flammable, non-explosive, and more stable at high temperatures, ensuring lithium-ion conductivity while also enhancing overall battery safety. The conductive agent comprises 2% of the material; it improves electronic conduction between active materials, significantly reducing resistance and ensuring good overall conductivity of the electrode. The binder comprises 5% of the material; an appropriate binder helps maintain the integrity of the electrode's internal structure. Through suitable material ratios, the safety, conductivity, and mechanical stability of the battery electrodes are improved.

[0041] For example, in one embodiment, the mass ratio of the active material, solid electrolyte, conductive agent, and binder is 75:20:3:2, and in another embodiment, the mass ratio of the active material, solid electrolyte, conductive agent, and binder is 75:18:2:5.

[0042] Specifically, the active material includes NCM811, the solid electrolyte includes Li6PS5Cl, the conductive agent includes VGCF, and the binder includes PTFE.

[0043] In this embodiment, NVM811 is a nickel-cobalt-manganese ternary cathode material, where "811" represents the molar ratio of nickel (Ni), cobalt (Co), and manganese (Mn) in the material, specifically 8:1:1. NVM811 contains a high amount of nickel, which significantly improves the battery's energy density. Li6PS5Cl is hexalithium thiophosphate chloride, a sulfide-based solid electrolyte material with good lithium-ion conductivity and electrochemical stability, avoiding the safety hazards of liquid electrolytes and preventing flammability and explosion. VGCF stands for Vertical Grow Carbon Fiber. VGCF enhances the conductive network inside the electrode, forming continuous conductive paths between active materials and reducing electrode resistance. PTFE stands for Polytetrafluoroethylene. PTFE has good chemical stability and high-temperature resistance, effectively enhancing the mechanical stability of the electrode.

[0044] like Figure 1 As shown in the embodiments of this application, a method for preparing a battery electrode sheet is also provided, including:

[0045] Step S1: Mix the active material, conductive agent, binder and solid electrolyte evenly to obtain a mixture.

[0046] Step S2: Fiberize the mixture;

[0047] Step S3: The fiberized mixture is extruded to obtain an initial self-supporting film, and the initial self-supporting film is thinned by a roll pressing process;

[0048] Step S4: Remove the edge region of the thinned initial self-supporting membrane to obtain the target self-supporting membrane;

[0049] Step S5: The target self-supporting film and foil 7 are thermally bonded and wound together using a thermal bonding process to obtain the battery electrode.

[0050] In step S1, the active material, conductive agent, binder, and solid electrolyte are mixed evenly to obtain a mixture. The uniformly distributed solid electrolyte ensures the uniform transport of lithium ions within the electrode. The uniform distribution of the conductive agent can build an efficient electronic conductivity network and reduce the internal resistance of the battery. The binder binds the various active material particles, conductive agent, and solid electrolyte together. The uniform distribution of the binder helps maintain the mechanical strength of the electrode. The uniform mixing of the materials can reduce the non-uniformity in the electrochemical reaction, improve the cycle stability of the battery, increase the battery's lifespan, and promote better interaction between the components.

[0051] In step S2, the fiberized material forms a fibrous structure, which can significantly enhance the mechanical strength of the electrode, making the electrode stronger and less prone to breakage. At the same time, the fiberization process helps to evenly disperse the components in the mixture, ensuring uniform distribution throughout the active material.

[0052] In step S3, the initial self-supporting film formed by extruding the fibrous mixture can maintain its shape without support, enhancing the independence of the electrode. By thinning the initial self-supporting film through the rolling process, the film density can be significantly increased, thereby improving the battery density. At the same time, the uniform thinning process also ensures the thickness consistency of the electrode. The self-supporting film is more flat and uniform after thinning.

[0053] In step S4, the edge region of the initial self-supporting film is cut off and thinned to ensure that the thickness in the center of the electrode is uniform. At the same time, cutting off the edge region can remove impurities during the extrusion and thinning process, thereby improving the electrochemical performance of the battery.

[0054] In step S5, the foil 7 typically exhibits good electrical conductivity. By thermally bonding it to the target self-supporting film containing a conductive agent, the conductivity of the battery electrode can be further improved. The thermal bonding process utilizes heat to intensify the molecular motion between the target self-supporting film and the foil 7, thereby enhancing the interfacial bonding force between the two and forming a more stable structure.

[0055] Based on steps S1-S5, through the improved solid-state battery electrode preparation method, from the mixing of raw materials to the final molding of the battery electrode, the structure and performance of the battery electrode are optimized, resulting in battery electrodes with high energy density, high power characteristics, good electrochemical performance and extremely high safety, thereby significantly improving the overall performance of solid-state batteries.

[0056] Further, in step S4, the width of the cut edge region is L, where 10mm≤L≤20mm.

[0057] In this embodiment, the edge area may deform due to uneven distribution of mechanical stress during extrusion and rolling. By removing 10mm-20mm of the edge area, defects can be removed and electrode performance can be guaranteed while minimizing material waste. Removing this part can ensure that the edge of the electrode is flatter and optimize the current conduction path.

[0058] Furthermore, such as Figure 3 As shown, in step S5, the target self-supporting film and foil 7 are thermally bonded and wound together using a thermal bonding process to obtain the battery electrode sheet, including the following steps:

[0059] Step S52: Cut the target self-supporting membrane into multiple sub-membrane pieces;

[0060] Step S53: Multiple sub-films and foil 7 are thermally bonded and wound together using a thermal bonding process to obtain a battery electrode with multiple spaced regions.

[0061] In step S52, by cutting the large-area self-supporting membrane into smaller sub-membrane pieces, the design and assembly of the battery module can be made more flexible. The smaller sub-membrane pieces can reduce the length of the internal current path in the electrochemical reaction, reduce the internal resistance of the battery, and thus improve the power density of the battery.

[0062] In step S53, the spacer region can increase the overall structural stability of the electrode and prevent the electrode from being deformed or damaged due to expansion and contraction during the battery charge and discharge cycle. At the same time, the spacer region helps to improve the heat dissipation efficiency of the battery.

[0063] Specifically, in step S2, the mixture is fiberized, which includes the following steps:

[0064] Step S21: The mixture is sheared at a first preset rotation speed until the temperature of the mixture reaches a first preset temperature, and the mixture is sheared at the first preset temperature and the first preset rotation speed for a first preset time to fiberize the binder. The first preset rotation speed is 3000 rpm, the first preset temperature is 80°C, and the first preset time is 1~2h.

[0065] In this embodiment, by shearing the mixture at a first preset rotation speed until the temperature of the mixture reaches a first preset temperature, high-speed shearing helps to quickly disperse the components in the mixture, ensuring the uniform distribution of active substances, solid electrolytes, conductive agents, and binders at the microscale. Continuing to shear at the first preset temperature can accelerate the fiberization of the binder, forming a fibrous binder network. By setting and controlling the rotation speed, temperature, and time of shearing, the process can be standardized and automated, improving production efficiency.

[0066] Preferably, such as Figure 2 As shown, in step S3, the fibrous mixture is extruded to obtain an initial self-supporting film, and the initial self-supporting film is thinned using a rolling process, including the following steps:

[0067] Step S31: The fiberized mixture is transferred to feeding unit 1, and an initial self-supporting membrane is obtained by extrusion through feeding unit 1;

[0068] Step S32: Control the rolling unit 2 to roll the initial self-supporting film with a first preset pressure and a second preset temperature until the thickness of the initial self-supporting film meets the preset thickness, and obtain the thinned initial self-supporting film. The first preset pressure is 20T, the second preset temperature is 100℃, and the thinned initial self-supporting film has a preset thickness H, 125μm≤H≤150μm.

[0069] In step S31, the fibrous material can be more evenly distributed during extrusion, and an initial self-supporting film is obtained by extrusion through feeding unit 1, ensuring the consistency of the thickness and composition of the initial self-supporting film.

[0070] In step S32, by adjusting the rolling pressure and temperature, the final thickness of the self-supporting film can be precisely controlled, ensuring the battery's energy density and internal resistance performance. Rolling under a first preset pressure increases the close contact between the components inside the electrode. The selection of a second preset temperature helps optimize the bonding between the active material, solid electrolyte, conductive agent, and binder. Appropriate rolling can enhance the mechanical strength of the electrode, making it more stable in subsequent thermal bonding and other processing steps. The reduced thickness of the self-supporting film helps shorten the distance lithium ions travel, reducing the battery's internal resistance. Preferably, H is 125 μm. Optionally, H can also be 150 μm or 135 μm.

[0071] Preferably, in step S3, the initial self-supporting film is thinned using a rolling process, including the following steps:

[0072] Step S33: The initial self-supporting film is rolled sequentially by multiple sub-rolling units 2 of the rolling unit 2 to thin the initial self-supporting film, wherein the gap between the multiple sub-rolling units 2 is set to decrease sequentially.

[0073] In this embodiment, the gradually decreasing roller gap allows the initial thickness of the self-supporting film to gradually decrease to a preset value after multiple rolling processes, avoiding material breakage or unevenness that may be caused by a single thinning. Multiple precision rolling processes can more accurately control the final film thickness and ensure the consistency of the thickness of each electrode layer.

[0074] Preferably, in step S1, the active material, conductive agent, binder, and solid electrolyte are mixed evenly to obtain a mixture, including the following steps:

[0075] Step S11: At a preset dew point temperature, add the active material, solid electrolyte, conductive agent, and binder to the mixer according to a preset mass ratio, control the mixing temperature of the mixer to a third preset temperature, and mix evenly at a second preset speed for a second preset time to obtain a mixture. The preset dew point temperature is less than -60℃, the third preset temperature is less than 18℃, the second preset speed is 1000 rpm, and the second preset time is 20 min.

[0076] In step S11, the dew point temperature refers to the temperature threshold at which moisture in the air begins to condense into water droplets. Mixing at the preset dew point temperature can effectively control the ambient humidity, avoid the influence of moisture on sensitive materials such as active materials and solid electrolytes, and ensure that the electrochemical performance of the materials is not impaired. Strictly adding each component according to the preset mass ratio can ensure the accuracy of the battery electrode composition. Controlling the third preset temperature during stirring can prevent excessive temperature from causing chemical reactions, while ensuring that the temperature is suitable to promote good integration between components. The setting of the second preset speed and the second preset stirring time ensures that each component is evenly dispersed during stirring to form a homogeneous mixture.

[0077] Embodiments of this application also provide a solid-state battery, including a battery electrode, wherein the battery electrode is the battery electrode described above, or the battery electrode is prepared by the method described above.

[0078] In this embodiment, solid-state batteries are used instead of liquid electrolytes, which significantly improves battery safety and reduces the risk of flammability and explosion. By using a high proportion of active materials and precisely controlled solid-state electrolytes, combined with optimized manufacturing processes, batteries with higher energy density can be achieved.

[0079] This application also provides a preferred embodiment of a method for preparing a solid-state battery electrode without thinning the region.

[0080] Specifically, the method for preparing the electrode sheet without thinning in a solid-state battery includes the following steps.

[0081] Step a: Mix the active material, conductive agent, binder, and solid electrolyte powder evenly to obtain a mixture.

[0082] Step b: The mixture is subjected to high-speed shear mixing and fiberization;

[0083] Step c: Extrude the fibrous material into a self-supporting membrane;

[0084] Step d: The self-supporting film is thinned by multi-stage rolling;

[0085] Step e: Cut off the edge area of ​​the self-supporting membrane with a cutter;

[0086] Step f: Directly heat-coat the self-supporting film and foil 7 and then roll them up, or cut the self-supporting film into sheets and then heat-coat it with foil 7 to form a roll.

[0087] Specifically, in one embodiment, such as Figure 4 As shown, the electrode preparation apparatus includes a feeding unit 1, a rolling unit 2, a foil unwinding unit 3, an edge trimming unit 4, and a thermal bonding unit 5. It employs... Figure 4 The dry continuous electrode prepared by the electrode preparation apparatus shown is as follows: Figure 5As shown, the dry continuous electrode includes a foil 7 and an active material layer 8.

[0088] Specifically, in one embodiment, such as Figure 6 As shown, the electrode preparation device includes a feeding unit 1, a rolling unit 2, a foil unwinding unit 3, an edge trimming unit 4, a thermal bonding unit 5, and a cutting unit 6. It employs... Figure 6 The dry continuous electrode prepared by the electrode preparation apparatus shown is as follows: Figure 7 As shown, the dry continuous electrode includes a foil 7 and an active material layer 8.

[0089] Specifically, using dry electrode technology, active materials, conductive agents, binders, and solid electrolytes are first rolled to form a self-supporting film. Then, the edges of the self-supporting film are cut off, and it is directly thermally laminated with foil 7 to form an electrode roll with no thinning areas, similar to continuous coating. Alternatively, the self-supporting film can be cut into sheets and thermally laminated with foil 7 to form an electrode roll with no edge or end thinning areas, similar to intermittent coating. Figure 4 As shown, the dry-process continuous cell electrode sheet includes a feeding unit 1, a rolling unit 2, a foil unwinding unit 3, an edge trimming unit 4, and a thermal bonding unit 5. Figure 5 As shown, the dry continuous electrode includes a foil 7 and an active material layer 8.

[0090] Preferably, this application provides Example 1 of a method for preparing a solid-state battery electrode without thinning the region. Example 1 uses... Figure 4 The electrode preparation apparatus shown performs electrode preparation, specifically including the following steps.

[0091] Step 1: At a dew point temperature of -60℃, add the active material NCM811, solid electrolyte Li6PS5Cl, conductive agent VGCF, and binder PTFE to a mixer in a mass ratio of 60~90:10~30:0.5~3:0.5~5 (preferably 75:20:3:2), control the temperature to <18℃, and stir at 500~5000rpm (preferably 1000rpm) for 20min to mix evenly.

[0092] Step 2: The mixture is subjected to natural shearing at a high speed of 3000 rpm and heated to 60℃~100℃ (preferably 80℃) to fiberize PTFE for 1~2 hours to obtain a dough-like mixture.

[0093] Step 3: Transfer the dough-like mixture to feeding unit 1, roll it at a pressure of 20T and a temperature of 80℃~120℃ (preferably 100℃) to obtain a self-supporting film with a thickness of 125um;

[0094] Step 4: Use a cutter to remove 10-20mm of the edge area on both sides of the self-supporting membrane to obtain a self-supporting membrane of uniform thickness;

[0095] Step 5: The self-supporting film is thermally bonded to foil 7 at 100°C to obtain a dry continuous electrode film.

[0096] This application provides Comparative Example 1, specifically, the method for preparing the solid-state battery electrode in Comparative Example 1 is as follows:

[0097] Step 1: At a dew point temperature of <-60℃, add the active material NCM811, solid electrolyte Li6PS5Cl, conductive agent VGCF, and binder PTFE to a mixer in a mass ratio of 60~90:10~30:0.5~3:0.5~5 (preferably 75:20:3:2), control the temperature to <18℃, and stir at 500~5000 rpm (preferably 1000 rpm) for 20 minutes to mix evenly.

[0098] Step 2: The mixture is subjected to natural shearing at a high speed of 3000 rpm and heated to 60℃~100℃ (preferably 80℃) to fiberize PTFE for 1~2 hours to obtain a dough-like mixture.

[0099] Step 3: Transfer the dough-like mixture to the feeding unit, press it under pressure of 20T, and multi-stage rolling at 80℃~120℃ (preferably 100℃) to obtain a self-supporting film with a thickness of 125um;

[0100] Step 4: The self-supporting film is thermally bonded with the foil at 100°C to obtain a dry continuous electrode film.

[0101] Preferably, this embodiment also provides an embodiment 2 of a method for preparing a solid-state battery electrode without thinning the region. Embodiment 2 adopts... Figure 6 The electrode preparation apparatus shown performs electrode preparation, specifically including the following steps.

[0102] Step 1: At a dew point temperature of -60℃, add the active material NCM811, solid electrolyte Li6PS5Cl, conductive agent VGCF, and binder PTFE to a mixer in a mass ratio of 60~90:10~30:0.5~3:0.5~5 (preferably 75:20:3:2), control the temperature to <18℃, and stir at 500~5000 rpm (preferably 1000 rpm) for 20 minutes to mix evenly.

[0103] Step 2: The mixture is subjected to natural shearing at a high speed of 3000 rpm and heated to 60℃~100℃ (preferably 80℃) to fiberize PTFE for 1~2 hours to obtain a dough-like mixture.

[0104] Step 3: Transfer the dough-like mixture to feeding unit 1, roll it at a pressure of 20T and a temperature of 80℃~120℃ (preferably 100℃) to obtain a self-supporting film with a thickness of 125um;

[0105] Step 4: Cut off 10-20mm edge areas on both sides of the self-supporting membrane with a cutter, and cut it into electrode sheets of the required size with a cutting knife to obtain a self-supporting membrane sheet with uniform thickness.

[0106] Step 5: The self-supporting membrane is thermally bonded to the foil 7 at 100°C to obtain a dry discontinuous electrode membrane.

[0107] This application provides Comparative Example 2, specifically, the solid-state battery electrode preparation method in Comparative Example 2 is as follows:

[0108] Step 1: At a dew point temperature of <-60℃, add the active material NCM811, solid electrolyte Li6PS5Cl, conductive agent VGCF, and binder PTFE to a double planetary mixer in a mass ratio of 60~90:10~30:0.5~3:0.5~5 (preferably 75:20:3:2), add solvent NMP, and mix thoroughly at 3000rpm for 240min.

[0109] Step 2: Coat the electrode into a continuous sheet using an extrusion coating machine.

[0110] The performance test results of Examples 1 and 2 and Comparative Examples 1 and 2 are as follows:

[0111] ACR test method: Under open circuit potential, frequency range 100KHz-0.1Hz, amplitude 50mV, battery impedance, test results are shown in Table 1.

[0112] DCR test method: At 25℃, adjust the cell SOC to 50%, discharge with a 1C current I, record the initial discharge voltage as V1 and the final discharge voltage as V2, DCR=(V1-V2) / I, the test results are shown in Table 1;

[0113] Cyclic test method: The batteries in the examples and comparative examples were charged at a constant current of 0.05C to 4.2V at 25±1℃ and left to stand for 5 minutes; then discharged at a constant current of 0.1C to 2.5V; the batteries were charged and discharged in this way until the discharge capacity was 80% of the initial capacity. The test results are shown in Table 1.

[0114] Table 1:

[0115]

[0116] Table 1 shows that, compared to the comparative example, the interface impedance of the embodiment is reduced and the battery cycle life is longer.

[0117] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0118] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0119] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0120] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0121] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0122] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0123] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0124] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A battery electrode, characterized in that, The battery electrode is prepared from a mixture of active material, solid electrolyte, conductive agent and binder, wherein the mass ratio of the active material, the solid electrolyte, the conductive agent and the binder is 60~90:10~30:0.5~3:0.5~5.

2. The battery electrode according to claim 1, characterized in that, The active material includes NCM811, the solid electrolyte includes Li6PS5Cl, the conductive agent includes VGCF, and the binder includes PTFE.

3. A method for preparing battery electrode sheets, characterized in that, include: Step S1: Mix the active material, conductive agent, binder and solid electrolyte evenly to obtain a mixture. Step S2, fiberize the mixture; Step S3: The fiberized mixture is extruded to obtain an initial self-supporting film, and the initial self-supporting film is thinned by a roll forming process; Step S4: Remove the edge region of the thinned initial self-supporting membrane to obtain the target self-supporting membrane; Step S5: The target self-supporting film and foil are thermally bonded and wound together using a thermal bonding process to obtain the battery electrode.

4. The method for preparing battery electrode sheets according to claim 3, characterized in that, In step S4, the width of the cut-off edge region is L, where 10mm ≤ L ≤ 20mm.

5. The method for preparing battery electrode sheets according to claim 3 or 4, characterized in that, In step S5, the target self-supporting film and foil are thermally bonded and wound together using a thermal bonding process to obtain the battery electrode sheet, including the following steps: Step S52: Cut the target self-supporting membrane into multiple sub-membrane pieces; Step S53: The multiple sub-films and the foil are thermally bonded and wound together using a thermal bonding process to obtain the battery electrode with multiple spaced regions.

6. The method for preparing battery electrode sheets according to claim 3 or 4, characterized in that, In step S2, the mixture is fiberized, including the following steps: Step S21: The mixture is sheared at a first preset rotation speed until the temperature of the mixture reaches a first preset temperature, and the mixture is sheared at the first preset temperature and the first preset rotation speed for a first preset time to cause the adhesive to become fibrous. The first preset rotation speed is 3000 rpm, the first preset temperature is 80°C, and the first preset time is 1~2 hours.

7. The method for preparing battery electrode sheets according to claim 3 or 4, characterized in that, In step S3, the fiberized mixture is extruded to obtain an initial self-supporting film, and the initial self-supporting film is thinned using a roll forming process, including the following steps: Step S31: The fiberized mixture is transferred to the feeding unit, and the initial self-supporting membrane is obtained by extrusion through the feeding unit; Step S32: Control the rolling unit to roll the initial self-supporting film with a first preset pressure and a second preset temperature until the thickness of the initial self-supporting film meets the preset thickness, and obtain the thinned initial self-supporting film. The first preset pressure is 20T, the second preset temperature is 100℃, and the thinned initial self-supporting film has a preset thickness H, 125μm≤H≤150μm.

8. The method for preparing battery electrode sheets according to claim 7, characterized in that, In step S3, the initial self-supporting film is thinned using a rolling process, including the following steps: Step S33: The initial self-supporting film is rolled sequentially by multiple sub-rolling units of the rolling unit to thin the initial self-supporting film, wherein the gap between the multiple sub-rolling units is sequentially reduced.

9. The method for preparing battery electrode sheets according to claim 3 or 4, characterized in that, In step S1, the active material, conductive agent, binder, and solid electrolyte are mixed evenly to obtain a mixture, including the following steps: Step S11: At a preset dew point temperature, the active material, the solid electrolyte, the conductive agent, and the binder are added to a mixer in a preset mass ratio. The mixing temperature of the mixer is controlled at a third preset temperature, and the mixture is stirred at a second preset speed for a second preset time to obtain the mixture. The preset dew point temperature is less than -60°C, the third preset temperature is less than 18°C, the second preset speed is 1000 rpm, and the second preset time is 20 min.

10. A solid-state battery, characterized in that, Includes a battery electrode sheet, wherein the battery electrode sheet is the battery electrode sheet according to claim 1 or 2, or the battery electrode sheet is prepared by the battery electrode sheet preparation method according to any one of claims 3 to 9.

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