Pole piece composite unit and preparation method thereof, and all-solid-state battery and preparation method thereof

Abstract

The invention provides a pole piece composite unit, a preparation method of the pole piece composite unit, an all-solid-state battery and a preparation method of the all-solid-state battery. The pole piece composite unit comprises a composite current collector (1) which comprises a diaphragm (100), a positive electrode metal conductive layer (102) arranged on a first side of the diaphragm (100) and a negative electrode metal conductive layer (101) arranged on a second side of the diaphragm (100), and the diaphragm (100), the positive electrode metal conductive layer (102) and the negative electrode metal conductive layer (101) are molded into a whole; the positive electrode active material (3) is coated on the positive electrode metal conductive layer (102); the negative electrode active material (2) is coated on the negative electrode metal conductive layer (101); the positive electrode tab (22) is connected to the positive electrode metal conductive layer (102); and the negative electrode tab (21) is connected to the negative electrode metal conductive layer (101). According to the pole piece composite unit, multiple times of positioning and transferring are not needed, the positioning precision is high, few devices are needed, the preparation process is simpler, and the product quality is higher.

Description

Technical Field

[0001] The present invention relates to the field of new energy battery technology, and in particular to a pole piece composite unit and a preparation method thereof, an all-solid-state battery and a preparation method thereof. Background Art

[0002] Currently, products on the commercial lithium battery market primarily rely on liquid organic electrolytes as a medium for electrochemical reactions. However, the use of liquid electrolytes poses significant safety challenges. Not only are they flammable, they can also cause explosions, especially when the battery is subjected to external impact or internal short circuits. This safety risk factor limits the application of lithium batteries in high-risk environments, such as aerospace, military, and electric vehicles. At the same time, liquid electrolytes and separators account for 30% to 40% of the total battery volume and approximately 25% of the total mass, which severely restricts the improvement of energy density. The bottleneck of energy density means that the battery's endurance is limited, and as modern technology continues to demand higher energy storage density, this limitation has become increasingly prominent.

[0003] In recent years, the emergence of solid-state battery technology has provided a possible solution to the above problems. Solid-state batteries use solid electrolytes instead of liquid organic electrolytes, which significantly improves the safety and stability of the battery. The non-flammable properties of solid electrolytes greatly reduce the risk of fire and explosion, making solid-state batteries safer than lithium batteries with liquid electrolytes. In addition, the volume and mass of solid electrolytes are much smaller than liquid electrolytes, which means that solid-state batteries can significantly increase the energy density of single cells, thereby providing longer battery life at the same volume. This feature makes solid-state batteries a very promising candidate for the next generation of high-performance lithium batteries, especially in electric vehicles and other applications with high energy density requirements.

[0004] However, the preparation process of all-solid-state batteries is still in the stage of exploration and optimization. At present, there is a link in the process technology that requires glue coating or rubber ring transfer after the positive and negative electrodes are prepared separately. This process is complicated and prone to errors. After the positive and negative electrodes are prepared separately, they need to be connected by glue coating or rubber ring transfer. This process not only requires precise control of the position of the electrodes to ensure the consistency of the size and position of the relative protruding parts between the positive and negative electrodes, but also faces the challenge of mechanical execution accuracy, which can easily lead to alignment deviations between the electrodes. The contradiction between the fixed size of the rubber ring and the uncertainty of the electrode position makes the rubber ring transfer extremely difficult. Before the battery cell is hot-pressed, the loose state between the electrodes may cause displacement during transportation, which further increases the difficulty and uncertainty in the process.

[0005] To address these issues, current manufacturing methods often require extensive equipment and multiple control steps, increasing costs and complexity. For example, after separately preparing the positive and negative electrodes, multiple positioning and transfer steps, as well as complex equipment control, are required to ensure precise alignment between the electrodes and proper transfer of the rubber rings, undoubtedly increasing the difficulty and cost of the process. Summary of the Invention

[0006] The main purpose of the present invention is to provide a pole piece composite unit and its preparation method, an all-solid-state battery and its preparation method, which do not require multiple positioning and transportation, have high positioning accuracy, require less equipment, have a simpler preparation process, and have higher product quality.

[0007] In order to achieve the above object, according to one aspect of the present invention, a pole piece composite unit is provided, comprising:

[0008] A composite current collector comprising a separator, a positive metal conductive layer disposed on a first side of the separator, and a negative metal conductive layer disposed on a second side of the separator, wherein the separator, the positive metal conductive layer, and the negative metal conductive layer are integrally formed;

[0009] Positive electrode active material, coated on the positive electrode metal conductive layer;

[0010] A negative electrode active material is coated on the negative electrode metal conductive layer;

[0011] The positive electrode tab is connected to the positive electrode metal conductive layer;

[0012] The negative electrode tab is connected to the negative electrode metal conductive layer.

[0013] After coating the positive and negative active materials, the positions of the formed positive and negative electrode sheets relative to the diaphragm are fixed, and there is no need for multiple positioning and transportation. The positioning accuracy is high and less equipment is required. Since the positioning and transportation links of the electrode sheets are omitted, the equipment control links are also greatly reduced, the preparation process is simpler, and the product quality is higher.

[0014] Furthermore, the electrode assembly unit also includes an apron, which is attached to the positive metal conductive layer side of the composite current collector and wraps around the positive active material. By directly coating the positive and negative electrode materials and transferring the apron onto the composite current collector, not only does it ensure the consistency and precise alignment of the battery's internal structure, it also significantly reduces equipment investment and control complexity.

[0015] Furthermore, the projection of the positive electrode active material coating area on the separator is within the projection of the negative electrode active material coating area on the separator. The width of the adhesive coating area between the edges of the positive electrode active material coating area and the negative electrode active material coating area is 1mm to 2mm. The rubber ring is located within the adhesive coating area, and the rubber ring adhesive width is smaller than the adhesive coating area width. This ensures that the rubber ring can fit tightly around the positive electrode active material to form an effective sealing structure, while preventing the rubber ring from exceeding the coverage area of ​​the negative electrode active material, ensuring the molding quality of the rubber ring.

[0016] Furthermore, the metal material of the positive and negative metal conductive layers is independent of each other, and the thickness of the positive and negative metal conductive layers is 0.2 to 3 μm. This ensures sufficient conductivity to promote efficient charge transfer while avoiding excessively thick metal layers that increase battery weight and affect energy density.

[0017] Furthermore, the positive electrode active material is at least one of lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium manganese oxide, and lithium iron manganese phosphate; the negative electrode active material is at least one of graphite, silicon, lithium metal, and a graphite silicon composite material; and the separator is at least one of polyethylene terephthalate, polypropylene, polyethylene, and polytetrafluoroethylene. By combining at least two materials, complementary and optimized performance indicators such as energy density, cost, cycle life, and safety can be achieved.

[0018] Furthermore, the thickness of the positive electrode active material is 100um to 450um, the thickness of the negative electrode active material is 100um to 600um, and the thickness of the separator is 3um to 10um. This allows the battery to accommodate more electrochemically active materials, thereby increasing the battery's energy density per unit volume.

[0019] Furthermore, the electrode composite unit also includes a solid electrolyte, which is connected to the side of the positive electrode active material away from the composite current collector or the side of the negative electrode active material away from the composite current collector. This reduces the safety risks of the battery under overcharge, overdischarge or thermal runaway conditions, such as the possibility of fire and explosion.

[0020] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned electrode composite unit, comprising:

[0021] Prepare a composite current collector, wherein the composite current collector includes a separator, a positive electrode metal conductive layer and a negative electrode metal conductive layer, and the separator, the positive electrode metal conductive layer and the negative electrode metal conductive layer are formed into one body;

[0022] Spraying positive electrode active material on the positive electrode metal conductive layer;

[0023] spraying negative electrode active material on the negative electrode metal conductive layer;

[0024] Connecting the positive electrode tab to the positive electrode side of the composite current collector;

[0025] Connect the negative electrode tab to the negative electrode side of the composite current collector.

[0026] It can accurately control the position and relative spacing of the active materials on the composite current collector. After coating the positive and negative active materials, the position of the positive and negative electrode sheets formed is fixed relative to the diaphragm, and there is no need for multiple positioning and transportation. The positioning accuracy is high and less equipment is required. Since the positioning and transportation links of the electrode sheets are omitted, the equipment control links are also greatly reduced, the preparation process is simpler, and the product quality is higher.

[0027] Furthermore, the preparation method further comprises:

[0028] Laminating the rubber ring on the positive electrode side of the composite current collector and wrapping it around the positive electrode active material;

[0029] A solid electrolyte is prepared on the side of the positive electrode active material or the negative electrode active material away from the composite current collector.

[0030] When preparing all-solid-state batteries, there is no need to prepare solid electrolytes separately. It is only necessary to directly stack multiple electrode composite units. The preparation process is simpler, more convenient and more efficient.

[0031] Furthermore, when preparing the composite current collector, multiple composite current collectors are connected by a separator, and the preparation method further includes:

[0032] After all the electrode composite units are formed, the multiple electrode composite units connected by the diaphragm are cut to form multiple independent electrode composite units.

[0033] It can facilitate the mass production of pole piece composite units, improve production efficiency and improve molding quality.

[0034] Furthermore, a composite current collector is prepared, wherein the composite current collector includes a separator, a positive electrode metal conductive layer, and a negative electrode metal conductive layer, and the steps of forming the separator, the positive electrode metal conductive layer, and the negative electrode metal conductive layer into one body include:

[0035] The positive electrode metal conductive layer and the negative electrode metal conductive layer are respectively covered on both sides of the diaphragm by a two-step method of magnetron sputtering and vacuum evaporation;

[0036] After the steps of spraying the positive electrode active material on the positive electrode metal conductive layer and spraying the negative electrode active material on the negative electrode metal conductive layer, the method further includes:

[0037] Drying the positive electrode active material and the negative electrode active material;

[0038] The dried positive electrode active material and negative electrode active material are rolled to make the positive electrode active material closely contact with the positive electrode metal conductive layer, and the negative electrode active material closely contact with the negative electrode metal conductive layer.

[0039] By precisely controlling the spraying range and thickness of the positive and negative active materials, as well as the subsequent drying and rolling processes, close contact between the active material layer and the metal conductive layer can be ensured, thereby improving the electrochemical performance and cycle stability of the battery.

[0040] According to another aspect of the present invention, an all-solid-state battery is provided, comprising the above-mentioned pole piece composite unit.

[0041] Furthermore, when the electrode composite unit includes an apron and a solid electrolyte, the all-solid-state battery comprises multiple stacked electrode composite units, each having the same layer structure sequence, and adjacent electrode composite units are connected by the solid electrolyte. During stacking, the electrode composite units are simply stacked in the same layer structure sequence and then hot-pressed, resulting in a simple and convenient molding method.

[0042] Furthermore, when the electrode composite unit includes an apron, the all-solid-state battery also includes a solid electrolyte. The electrode composite units and the solid electrolyte are alternately arranged and stacked in a sequential manner. The layer structure sequence of each electrode composite unit is the same, and adjacent electrode composite units are connected by the solid electrolyte. The solid electrolyte does not need to be considered when forming the electrode composite unit, thereby simplifying the forming process of the electrode composite unit and reducing the difficulty of forming the electrode composite unit.

[0043] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned all-solid-state battery, comprising:

[0044] Preparing a plurality of pole piece composite units, wherein the layer structure sequence of each pole piece composite unit is the same;

[0045] Multiple pole piece composite units are stacked in sequence and then hot pressed into shape;

[0046] Weld all the positive tabs together;

[0047] Weld all the negative electrode tabs together to form a battery cell.

[0048] In the above preparation method, when stacking the electrode composite units, the electrode composite units are directly stacked in the same layer structure order, and finally hot pressed. The molding method is simple and convenient.

[0049] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned all-solid-state battery, comprising:

[0050] Preparing a plurality of pole piece composite units, wherein the layer structure sequence of each pole piece composite unit is the same;

[0051] Prepare solid electrolyte;

[0052] Multiple electrode composite units and solid electrolytes are stacked alternately in sequence and then hot-pressed into shape;

[0053] Weld all the positive tabs together;

[0054] Weld all the negative electrode tabs together to form a battery cell.

[0055] In the above-mentioned preparation method, solid electrolytes are arranged between adjacent electrode composite units, so that the electrode composite units and the solid electrolytes are arranged alternately and then hot-pressed as a whole, resulting in good structural consistency.

[0056] By applying the technical solution of the present invention, active materials are successively coated on both sides of a composite current collector that integrates a diaphragm, a positive metal conductive layer, and a negative metal conductive layer. This allows for precise control of the position and relative spacing of the active materials on the composite current collector, which is beneficial for improving the accuracy of the rubber ring fitting on the positive side of the composite current collector. In the existing mainstream solid-state battery preparation process, the positive and negative electrodes need to be separately prepared, stacked, and fitted with rubber rings, requiring multiple positioning and transportation of the pole pieces, requiring a large investment in equipment, and multiple equipment control links. In the present invention, through the above-mentioned optimized structure, after coating the positive and negative active materials, the position of the positive and negative pole pieces relative to the diaphragm is fixed, and there is no need for multiple positioning and transportation. The positioning accuracy is high, and less equipment is required. Since the positioning and transportation link of the pole pieces is omitted, the equipment control link is also greatly reduced, the preparation process is simpler, and the product quality is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0058] Figure 1 2 is a schematic structural diagram of a pole piece composite unit according to an embodiment of the present invention;

[0059] Figure 2 1 is a schematic side view of the structure of a pole piece composite unit according to an embodiment of the present invention;

[0060] Figure 3 Schematic diagram of the pole piece structure of the pole piece composite unit according to an embodiment of the present invention;

[0061] Figure 4 Schematic diagram of the structure of the composite current collector of the electrode composite unit according to an embodiment of the present invention;

[0062] Figure 5This is a schematic structural diagram of a pole piece composite unit after being coated with a rubber ring according to an embodiment of the present invention;

[0063] Figure 6 This is a schematic structural diagram of a pole piece composite unit after welding pole tabs according to an embodiment of the present invention;

[0064] Figure 7 Schematic diagram of the stacking structure of the electrode composite unit according to an embodiment of the present invention;

[0065] Figure 8 is a schematic structural diagram of an all-solid-state battery according to an embodiment of the present invention; and

[0066] Figure 9 It is a flow chart of a method for preparing a pole piece composite unit according to an embodiment of the present invention.

[0067] The above drawings include the following reference numerals:

[0068] 1. Composite current collector; 100. Separator; 101. Negative electrode metal conductive layer; 102. Positive electrode metal conductive layer; 2. Negative electrode active material; 3. Positive electrode active material; 21. Negative electrode tab; 22. Positive electrode tab; 4. Solid electrolyte; 5. Rubber ring. DETAILED DESCRIPTION

[0069] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0070] See also Figures 1 to 8 As shown, according to an embodiment of the present invention, the electrode composite unit includes: a composite current collector 1, including a diaphragm 100, a positive electrode metal conductive layer 102 arranged on the first side of the diaphragm 100, and a negative electrode metal conductive layer 101 arranged on the second side of the diaphragm 100, and the diaphragm 100, the positive electrode metal conductive layer 102 and the negative electrode metal conductive layer 101 are formed as one body; a positive electrode active material 3, coated on the positive electrode metal conductive layer 102; a negative electrode active material 2, coated on the negative electrode metal conductive layer 101; a positive electrode tab 22, connected to the positive electrode metal conductive layer 102; a negative electrode tab 21, connected to the negative electrode metal conductive layer 101.

[0071] The composite current collector 1 integrates the separator 100, the positive metal conductive layer 102, and the negative metal conductive layer 101 into a single body, allowing the positive and negative metal conductive layers 102 and 101 to be positioned directly on the separator 100. This improves the distribution accuracy of the positive and negative metal conductive layers 102 and 101 on the separator 100, eliminates the separation between the separator and the metal conductive layer in traditional batteries, and reduces alignment errors during assembly. The positive active material 3 and the negative active material 2 are coated on the positive and negative metal conductive layers 102 and 101, respectively. By precisely controlling the coating area, the uniform distribution and thickness consistency of the positive and negative active materials can be ensured, thereby ensuring the uniformity of the battery cell energy density and the consistency of the electrochemical performance.

[0072] The positive electrode tab 22 is directly connected to the positive electrode metal conductive layer 102, and the negative electrode tab 21 is directly connected to the negative electrode metal conductive layer 101. This shortens the path between the tab and the electrode material, reduces the internal resistance of the battery, and improves the current collection efficiency. At the same time, the direct connection between the metal conductive layer and the tab also enhances the mechanical stability of the battery, preventing the tab from loosening or falling off during the battery's charge and discharge cycles, thereby extending the battery's service life. The use of a solid electrolyte instead of a liquid electrolyte significantly reduces the amount of flammable materials inside the battery, reducing the risk of fire and explosion due to internal short circuits or external impacts.

[0073] By successively coating active materials on both sides of the composite current collector that integrates the diaphragm 100, the positive electrode metal conductive layer 102, and the negative electrode metal conductive layer 101, the position and relative spacing of the active materials on the composite current collector 1 can be precisely controlled, which is beneficial to improving the fitting accuracy of the rubber ring 5 on the positive electrode side of the composite current collector 1. In the existing mainstream solid-state battery preparation process, the positive and negative electrodes need to be separately prepared, stacked, and fitted with rubber rings, which requires multiple positioning and transportation of the pole pieces, a large amount of equipment investment, and many equipment control links. In the present invention, through the above-mentioned optimized structure, after coating the positive and negative active materials, the positive and negative pole pieces formed are fixed relative to the diaphragm 100, and there is no need for multiple positioning and transportation. The positioning accuracy is high and the required equipment is small. Since the positioning and transportation link of the pole pieces is omitted, the equipment control link is also greatly reduced, the preparation process is simpler, and the product quality is higher.

[0074] The diaphragm 100 is, for example, a polymer film.

[0075] The material of the polymer film is at least one of polyethylene terephthalate, polypropylene, polyethylene and polytetrafluoroethylene.

[0076] In one embodiment, the electrode composite unit further includes a rubber ring 5 , which is attached to the side of the composite current collector 1 where the positive electrode metal conductive layer 102 is located, and is wrapped around the positive electrode active material 3 .

[0077] The rubber ring 5 is attached to the side of the composite current collector 1 where the positive metal conductive layer 102 is located and accurately wraps the positive active material 3, which can integrate multiple traditional process steps into a coherent process. By directly completing the coating of positive and negative electrode materials and the transfer of the rubber ring on the composite current collector, it not only ensures the consistency and precise alignment of the internal structure of the battery, but also greatly reduces the equipment investment and the complexity of the control link.

[0078] After the positive electrode active material 3 is coated on the positive electrode metal conductive layer 102, the rubber ring 5 is immediately fitted and wrapped around the positive electrode active material layer. The electrode composite unit is cut only after the rubber ring is fitted. This cleverly avoids the problem of inconsistency in the size and position of the relative excess parts between the positive and negative electrodes that may occur when the electrodes are positioned and transported multiple times in the traditional process, simplifies the process, reduces equipment investment, and reduces production costs.

[0079] In one embodiment, the projection of the coating area of ​​the positive electrode active material 3 on the diaphragm 100 is located within the range of the projection of the coating area of ​​the negative electrode active material 2 on the diaphragm 100, the width of the glue coating area between the edge of the coating area of ​​the positive electrode active material 3 and the edge of the coating area of ​​the negative electrode active material 2 is 1 mm to 2 mm, the rubber ring 5 is located within the range of the glue coating area, and the glue width of the rubber ring 5 is smaller than the width of the glue coating area.

[0080] In one embodiment, the width of the rubber ring 5 is 0.8 mm to 1.2 mm.

[0081] The rubber ring 5 is located in a specific glue-coated area between the positive and negative active materials on the diaphragm 100. The design of its glue width being smaller than the width of the glue-coated area ensures that the rubber ring can fit tightly around the positive active material 3 to form an effective sealing structure. At the same time, it avoids the rubber ring 5 from exceeding the coverage range of the negative active material 2, thereby ensuring the molding quality of the rubber ring 5.

[0082] By precisely controlling the relative positions of the positive electrode active material 3 and the negative electrode active material 2 on the composite current collector 1 and combining the precise fitting of the rubber ring 5, the positional consistency of each electrode composite unit during the stacking process can be ensured, thereby improving the uniformity of the battery cell and contributing to the improvement of the overall performance of the battery.

[0083] In one embodiment, the metal material of the positive metal conductive layer 102 and the metal material of the negative metal conductive layer 101 are independent of each other, and the thickness of the positive metal conductive layer 102 and the negative metal conductive layer 101 is 0.2 um to 3 um.

[0084] By selecting separate metal materials for the positive and negative metal conductive layers 102 and 101, it is possible to select the most suitable metal materials based on the different properties and reaction mechanisms of the positive and negative active materials 3 and 2, respectively. For example, aluminum or stainless steel can be selected for the positive metal conductive layer 102, while copper or nickel can be selected for the negative metal conductive layer 101 to balance conductivity and chemical compatibility with the active materials, thereby improving the electrochemical performance and cycle life of the battery.

[0085] Keeping the thickness of the metal conductive layer within the range of 0.2um to 3um ensures sufficient conductivity to facilitate efficient charge transfer while avoiding excessively thick metal layers that increase battery weight and affect energy density. The thin metal conductive layer design also effectively reduces internal resistance and increases the battery's power density.

[0086] The introduction of the solid electrolyte 4 allows the metal conductive layer to be thinner than in liquid-state batteries without increasing the risk of internal short circuits. Within this thickness range, the metal conductive layer is less likely to deform or break even when subjected to external forces, thereby enhancing the battery's mechanical stability and reducing potential safety hazards.

[0087] Precise control of the thickness of the metal conductive layer, combined with preparation techniques such as magnetron sputtering or vacuum evaporation, can reduce the amount of material used while ensuring electrical performance, thereby reducing production costs.

[0088] The thin layer design of the positive metal conductive layer 102 and the negative metal conductive layer 101 is conducive to improving the bonding strength with the diaphragm 100, making the entire composite current collector tighter during subsequent coating, hot pressing, welding and other processes, which helps to enhance the tightness of the battery packaging and improve the overall structural stability and reliability of the battery.

[0089] In one embodiment, the material of the metal conductive layer can be selected from one of aluminum, copper, nickel, stainless steel, and silver.

[0090] The choice of metal conductive layer material has a significant impact on the performance of all-solid-state batteries. By selecting aluminum, copper, nickel, stainless steel, or silver, the battery's conductivity, chemical compatibility, mechanical strength, cost-effectiveness, safety, and environmental adaptability can be optimized according to specific application requirements, thereby improving the overall performance and market competitiveness of all-solid-state batteries.

[0091] In one embodiment, the material of the positive electrode active material 3 is at least one of lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium manganese oxide, and lithium manganese iron phosphate.

[0092] Ternary materials such as lithium nickel cobalt manganese oxide (LMO) are widely adopted due to their high energy density and long cycle life, significantly improving overall battery performance. Lithium cobalt oxide's high voltage platform excels in small, high-power applications. Lithium manganese oxide and lithium iron manganese phosphate (LMP) are renowned for their excellent thermal stability and safety, making them suitable for applications with high safety requirements.

[0093] The selected positive electrode material has high chemical stability and thermal stability, which can effectively reduce the side reactions of the battery during the charging and discharging process, reduce the risk of battery overheating and thermal runaway, and thus improve the safety performance of all-solid-state batteries.

[0094] Different cathode materials have different electrochemical properties. For example, lithium cobalt oxide has a high discharge voltage and good cycle stability, but cobalt resources are scarce and costly. Lithium nickel cobalt manganese oxide has a high energy density, but nickel content and safety are concerns. Lithium manganese oxide has good safety and cycle performance, but low energy density. Lithium iron manganese phosphate has low cost and good safety, but a low voltage platform. By combining at least two materials, it is possible to achieve complementary and optimized performance in key performance indicators such as energy density, cost, cycle life, and safety.

[0095] In one embodiment, the material of the negative electrode active material 2 is at least one of graphite, silicon, lithium metal, and graphite-silicon composite material.

[0096] Graphite is a commonly used anode material in traditional lithium-ion batteries, boasting a stable crystal structure and excellent cycling performance. Silicon, with a theoretical capacity far exceeding that of graphite, can significantly increase the battery's energy density. Lithium metal, with its highest theoretical capacity and most negative electrochemical potential, is the preferred material for achieving high energy density, but it suffers from the problem of lithium dendrite growth. Graphite-silicon composites combine the stability of graphite with the high capacity of silicon, achieving a balance between energy density and cycling stability.

[0097] By combining at least two negative electrode active materials, complementary optimization between energy density, cycle stability, safety, and cost can be achieved. For example, the combination of graphite and silicon can leverage the stability of graphite to mitigate silicon's volume changes, thereby improving cycle life. Meanwhile, the combination of graphite or a graphite-silicon composite with lithium metal can leverage the high capacity of lithium metal to increase energy density, while simultaneously controlling the growth of lithium dendrites and improving safety through the structural stability and good electronic conductivity of the graphite or composite material.

[0098] In one embodiment, the thickness of the positive electrode active material 3 is 100 um to 450 um, the thickness of the negative electrode active material 2 is 100 um to 600 um, and the thickness of the separator 100 is 3 um to 10 um.

[0099] The thickness of the active material is directly related to the battery's energy density. The thickness of the positive electrode active material ranges from 100um to 450um, and the thickness of the negative electrode active material ranges from 100um to 600um. This allows the battery to accommodate more electrochemically active material, thereby increasing the battery's energy density per unit volume. The thickness of the active material layer must balance capacity and cycle stability. An overly thick active material layer may lead to structural instability during charge and discharge, affecting cycle life. The set thickness range ensures energy density while avoiding structural issues caused by increased material thickness, thereby optimizing the battery's cycle life.

[0100] The thickness of the diaphragm 100 is controlled between 3um and 10um, which not only ensures effective isolation between the electrodes and prevents internal short circuits, but also minimizes the impact of the diaphragm on the overall energy density of the battery. In addition, a thin diaphragm is conducive to the rapid transfer of charge, reduces the internal resistance of the battery, and increases the power density. However, the diaphragm cannot be too thin to ensure sufficient mechanical strength and chemical stability. The selection of the thickness of the active material layer and the diaphragm needs to balance cost and performance. An active material layer that is too thick will increase the material cost, while a diaphragm that is too thin may not provide adequate protection. The set thickness range not only ensures battery performance, but also takes into account cost control, so that the all-solid-state battery achieves a reasonable balance between cost and performance.

[0101] In one embodiment, the electrode composite unit further includes a solid electrolyte 4 , which is connected to the side of the positive electrode active material 3 away from the composite current collector 1 or the side of the negative electrode active material 2 away from the composite current collector 1 .

[0102] Solid-state electrolytes replace the flammable liquid electrolytes in traditional lithium-ion batteries, significantly improving battery safety. The solid electrolyte layer is in direct contact with the active material layer, reducing the participation of liquid electrolytes in internal electrochemical reactions and lowering the safety risks of the battery under overcharge, over-discharge, or thermal runaway conditions, such as fire and explosion. Compared to liquid electrolytes, solid electrolyte layers have a smaller volume and mass ratio, providing more space for active materials. This design allows the battery to accommodate more active materials in a more compact space, thereby increasing the battery's energy density. At the same time, the use of solid electrolytes helps reduce the ineffective volume within the battery, further improving the energy storage capacity per unit volume.

[0103] In one embodiment, the thickness of the solid electrolyte 4 is 8 um to 100 um.

[0104] The thickness of the solid electrolyte 4 is designed to be between 8um and 100um. The selection of this range helps to balance the electrochemical performance, internal resistance and cost of the battery, while ensuring sufficient ionic conductivity and mechanical stability, thereby improving the energy density and safety of the all-solid-state battery.

[0105] In one embodiment, the material of the solid electrolyte 4 is at least one of a sulfide solid electrolyte membrane, a polymer solid electrolyte membrane, an oxide solid electrolyte membrane, or a chloride solid electrolyte membrane.

[0106] Selecting sulfide, polymer, oxide or chloride solid electrolyte membrane as the material of solid electrolyte 4 can optimize ionic conductivity, mechanical strength and chemical stability according to battery performance requirements, thereby effectively improving the safety, energy density and cycle life of all-solid-state batteries.

[0107] In one embodiment, the thickness of each positive electrode tab is 10 to 20 μm, and the thickness of each negative electrode tab is 4.5 to 10 μm. This design ensures good electrical connectivity and mechanical strength while controlling the volume and weight of the battery, helping to improve the energy density and overall performance stability of all-solid-state batteries.

[0108] See also Figure 9 As shown, according to an embodiment of the present invention, a method for preparing the above-mentioned electrode composite unit includes:

[0109] Prepare a composite current collector 1, wherein the composite current collector 1 includes a separator 100, a positive electrode metal conductive layer 102, and a negative electrode metal conductive layer 101, and the separator 100, the positive electrode metal conductive layer 102, and the negative electrode metal conductive layer 101 are formed into one body;

[0110] Coating the positive electrode active material 3 on the positive electrode metal conductive layer 102;

[0111] Coating the negative electrode active material 2 on the negative electrode metal conductive layer 101;

[0112] Connect the positive electrode tab 22 to the positive electrode side of the composite current collector 1;

[0113] A negative electrode tab 21 is connected to the negative electrode side of the composite current collector 1 .

[0114] The electrode composite unit prepared by the above preparation method first accurately positions the positive metal conductive layer 102 and the negative metal conductive layer 101 on the diaphragm 100 and forms them into one body with the diaphragm 100, and then coats the positive active material 3 on the positive metal conductive layer 102 and the negative active material 2 on the negative metal conductive layer 101. The position and relative spacing of the active materials on the composite current collector 1 can be accurately controlled. After coating the positive and negative active materials, the positions of the formed positive and negative electrode sheets relative to the diaphragm 100 are fixed, and there is no need for multiple positioning and transportation. The positioning accuracy is high and less equipment is required. Since the positioning and transportation link of the electrode sheet is omitted, the equipment control link is also greatly reduced, the preparation process is simpler, and the product quality is higher.

[0115] In one embodiment, the preparation method further comprises:

[0116] Attach the rubber ring 5 to the positive electrode side of the composite current collector 1 and wrap around the positive electrode active material 3;

[0117] A solid electrolyte 4 is prepared on the side of the positive electrode active material 3 or the negative electrode active material 2 away from the composite current collector 1 .

[0118] Through the above method, a solid electrolyte 4 can be provided on one side of the formed electrode composite unit. When preparing an all-solid-state battery, there is no need to prepare the solid electrolyte 4 separately. Instead, multiple electrode composite units can be directly stacked, making the preparation process simpler, more convenient, and more efficient. By preparing the solid electrolyte outside the positive and negative active materials, the use of liquid electrolytes can be effectively avoided, improving the safety and energy density of the battery. The solid electrolyte can provide a stable ion conduction channel, ensuring the electrochemical performance of the battery during the charge and discharge process.

[0119] The rubber ring 5 is attached to the positive electrode side of the composite current collector 1 through transfer printing, wrapping around the positive electrode active material 3. This rubber ring transfer technology precisely controls the position and size of the rubber ring, ensuring a tight seal between the positive electrode active material layer and the composite current collector, thereby improving the battery's sealing performance and safety. This rubber ring attachment effectively prevents contact between the active material inside the battery and the external environment, preventing performance degradation and safety accidents during battery use.

[0120] In one embodiment, when preparing the composite current collector 1, multiple composite current collectors 1 are connected via a separator 100, and the preparation method further includes:

[0121] After all the electrode composite units are formed, the multiple electrode composite units connected by the diaphragm 100 are cut to form multiple independent electrode composite units.

[0122] In this embodiment, when forming the electrode composite unit, the diaphragm 100 is a continuous, long-length integral structure. The positive electrode metal conductive layer 102 and the negative electrode metal conductive layer 101 are sequentially formed on the diaphragm 100 at preset intervals to form a plurality of composite current collectors 1 connected by the diaphragm 100. Subsequently, a plurality of electrode composite units connected by the diaphragm 100 can be prepared according to the aforementioned steps. After each electrode composite unit is prepared, the diaphragm 100 can be cut to form a plurality of electrode composite unit monomers, facilitating the subsequent preparation of all-solid-state batteries. Through the above steps, it is possible to facilitate the mass production of electrode composite units, improve production efficiency, and improve molding quality.

[0123] In one embodiment, the steps of preparing a composite current collector 1, wherein the composite current collector 1 includes a separator 100, a positive electrode metal conductive layer 102, and a negative electrode metal conductive layer 101 formed into one body, include:

[0124] A two-step process, magnetron sputtering and vacuum evaporation, is used to coat the positive and negative metal conductive layers 102 and 101 on either side of the separator 100. This composite current collector method ensures a close bond between the metal conductive layer and the polymer film, forming a stable composite structure that effectively improves the battery's electrical conductivity and structural stability. Magnetron sputtering and vacuum evaporation techniques precisely control the thickness and uniformity of the metal layer, ensuring close contact between the positive and negative electrode materials and the metal conductive layer, thereby improving the battery's electrochemical performance.

[0125] Laser cutting and die-cutting processes transform rolled pole pieces into pole piece composite units, enabling precise cutting and shaping of the pole piece composite units, ensuring that their dimensions and structure meet design requirements. Laser cutting and die-cutting techniques effectively avoid dimensional deviations and structural damage that can occur with traditional cutting methods, thereby improving battery stability and safety.

[0126] After the steps of spraying the positive electrode active material 3 on the positive electrode metal conductive layer 102 and spraying the negative electrode active material 2 on the negative electrode metal conductive layer 101, the following steps are further included:

[0127] Drying the positive electrode active material 3 and the negative electrode active material 2;

[0128] The dried positive electrode active material 3 and negative electrode active material 2 are roll-pressed to ensure that the positive electrode active material 3 is in close contact with the positive electrode metal conductive layer 102 , and the negative electrode active material 2 is in close contact with the negative electrode metal conductive layer 101 .

[0129] The positive electrode active material is sprayed onto the metal conductive layer on the positive side of the composite current collector, and the negative electrode active material is sprayed onto the metal conductive layer on the negative side of the composite current collector. The process is then dried to form a positive electrode active material layer on the positive side of the composite current collector, and a negative electrode active material layer on the negative side of the composite current collector. Finally, the positive electrode active material layer and the negative electrode active material layer are rolled to ensure close contact between the positive electrode active material layer and the metal conductive layer on the negative electrode side. By precisely controlling the spraying range and thickness of the positive and negative electrode active materials, as well as the subsequent drying and rolling processes, close contact between the active material layer and the metal conductive layer can be ensured, thereby improving the battery's electrochemical performance and cycle stability.

[0130] In one embodiment, the steps of connecting the positive electrode tab 22 on the positive electrode side of the composite current collector 1 and connecting the negative electrode tab 21 on the negative electrode side of the composite current collector 1 include: using a roll welding process to weld the positive electrode foil on the positive electrode side of the composite current collector to form the positive electrode tab 22, and welding the negative electrode foil on the negative electrode side of the composite current collector to form the negative electrode tab 21.

[0131] The roll welding process achieves a reliable connection between the tab and the composite current collector, ensuring efficient current transmission during the battery's charge and discharge processes. This process effectively avoids problems such as cold joints and short circuits that can occur with traditional welding methods, thereby improving battery stability and safety.

[0132] See also Figures 1 to 8 As shown, according to an embodiment of the present invention, the all-solid-state battery includes the above-mentioned pole piece composite unit.

[0133] The all-solid-state battery includes all the advantages of the aforementioned pole piece composite unit.

[0134] In one embodiment, when the electrode composite unit includes an apron 5 and a solid electrolyte 4, the all-solid-state battery includes multiple stacked electrode composite units, each of which has the same layer structure sequence, and adjacent electrode composite units are connected by the solid electrolyte 4. Through the above method, the electrode composite unit has both the apron 5 and the solid electrolyte 4. Therefore, when stacking, the electrode composite units can be directly stacked in the same layer structure sequence and finally hot pressed, which is a simple and convenient molding method.

[0135] In one embodiment, when the pole piece composite unit includes an apron 5, the all-solid-state battery also includes a solid electrolyte 4. The pole piece composite unit and the solid electrolyte 4 are arranged alternately and stacked in a sequential stacking manner. The layer structure order of each pole piece composite unit is the same, and adjacent pole piece composite units are connected by the solid electrolyte 4. In the above manner, the pole piece composite unit is provided with an apron 5. During molding, it is necessary to set a solid electrolyte 4 between adjacent pole piece composite units. In this case, the pole piece composite unit does not include the solid electrolyte 4, and the solid electrolyte 4 needs to be prepared and stacked separately. This method makes it unnecessary to consider the solid electrolyte 4 when molding the pole piece composite unit, thereby simplifying the molding process of the pole piece composite unit and reducing the molding difficulty of the pole piece composite unit.

[0136] The same layer structure order of each electrode composite unit means that during the stacking process of each electrode composite unit, the positive electrode active material 3 is located on the upper side and the negative electrode active material 2 is located on the lower side, or the positive electrode active material 3 is located on the lower side and the negative electrode active material 2 is located on the upper side.

[0137] According to an embodiment of the present invention, a method for preparing the above-mentioned all-solid-state battery includes:

[0138] Preparing a plurality of pole piece composite units, wherein the layer structure sequence of each pole piece composite unit is the same;

[0139] Multiple pole piece composite units are stacked in sequence and then hot pressed into shape;

[0140] Welding all the positive electrode tabs 22 together;

[0141] All the negative electrode tabs 21 are welded together to form a battery cell.

[0142] In the above preparation method, when stacking the electrode composite units, the electrode composite units are directly stacked in the same layer structure order, and finally hot pressed. The molding method is simple and convenient.

[0143] By sequentially stacking the electrode composite units and performing hot pressing, efficient battery cell assembly can be achieved, ensuring the structural stability and electrochemical performance of the battery cells. Hot pressing can effectively increase the contact area between the positive and negative electrode materials and the solid electrolyte layer, thereby improving the electrochemical performance and cycle stability of the battery.

[0144] According to an embodiment of the present invention, a method for preparing the above-mentioned all-solid-state battery includes:

[0145] Preparing a plurality of pole piece composite units, wherein the layer structure sequence of each pole piece composite unit is the same;

[0146] Prepare solid electrolyte 4;

[0147] Multiple electrode composite units and solid electrolytes 4 are alternately stacked in sequence and then hot-pressed into shape;

[0148] Welding all the positive electrode tabs 22 together;

[0149] All the negative electrode tabs 21 are welded together to form a battery cell.

[0150] The above-mentioned preparation method arranges the solid electrolyte 4 between adjacent electrode composite units, so that the electrode composite units and the solid electrolyte 4 are arranged alternately, and then the whole is hot-pressed, with good structural consistency, good molding structural strength of adjacent electrode composite units and solid electrolyte 4, and good structural strength of the battery.

[0151] Example:

[0152] Preparation of composite current collector: A two-step method of vacuum magnetron sputtering and electroplating in an aqueous environment was used to prepare a 1um thick copper metal layer on one side of a 4.5um thick and 200mm wide PET polymer negative electrode, and a 1.5um thick aluminum metal layer on the positive side of the PET polymer.

[0153] Preparation of pole piece composite unit:

[0154] 1. Using gap coating technology, 180mm of lithium nickel cobalt manganese oxide positive electrode active material is coated in the center of the positive electrode side of the composite current collector 1 with a width of 200mm. A 10mm blank is reserved on the positive metal conductive layer 102 in the X direction for coating intervals and rubber ring transfer; in the Y direction, 10mm of blank is reserved at the upper and lower ends of the positive metal conductive layer 102 for rubber ring transfer and tab welding; the thickness of the lithium nickel cobalt manganese oxide positive electrode active material is 400um; a graphite negative electrode active material layer is coated on one side of the negative metal conductive layer 101 of the composite current collector 1 with a width of 180mm. A 10mm blank is reserved on the positive metal conductive layer 102 in the X direction for coating intervals; in the Y direction, 10mm of blank is reserved at the upper and lower ends of the positive metal conductive layer 102 for tab welding; the thickness of the graphite negative electrode active material is 200um.

[0155] 2. Dry the electrode, and control the inorganic solvent and moisture content at 200PPM.

[0156] 3. Roll-press the electrode to increase the compaction density. The positive electrode compaction density reaches 3.4g / cm 3 The negative electrode compaction density is 1.8g / cm 3 .

[0157] 4. Attach the rubber ring 5 to the PET base film and transfer the rubber ring 5 on the PET base film to the periphery of the positive electrode active material 3;

[0158] 5. Using the roll welding process, weld aluminum foil on the positive metal conductive layer 102 of the composite current collector 1 with a weld print width of 3 mm; weld copper foil on the negative metal conductive layer 101 of the composite current collector 1 with a weld print width of 3 mm.

[0159] 6. The rolled pole pieces are made into pole piece composite units through the laser cutting process.

[0160] Preparation of solid-state batteries:

[0161] 1. When stacking the pole pieces, the pole piece composite units containing the solid electrolyte 4 are placed in the same structural order and stacked on the mold, or the pole piece composite units not containing the solid electrolyte 4 are placed in the same structural order and arranged alternately with the solid electrolyte 4 and stacked on the mold;

[0162] 2. In an environment filled with Ar or other protective gas, perform flat hot pressing on the electrode at 150°C and 60 MPa pressure for 2 minutes;

[0163] 3. Use ultrasonic welding to weld the tabs and tabs to form solid-state battery cells.

[0164] 4. Punch the aluminum-plastic film. After placing the solid-state battery, heat-seal the aluminum-plastic film on the positive and negative ear sides, leaving an opening on one side for the discharge of the gas produced by the chemical composition;

[0165] 5. The battery is charged and discharged at a current of 0.5C under static pressure.

[0166] 6. Seal with aluminum-plastic film to form a complete soft-pack solid-state battery.

[0167] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0168] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0169] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A pole piece composite unit, characterized in that: include: A composite current collector (1) comprises a diaphragm (100), a positive metal conductive layer (102) arranged on a first side of the diaphragm (100), and a negative metal conductive layer (101) arranged on a second side of the diaphragm (100), wherein the diaphragm (100), the positive metal conductive layer (102), and the negative metal conductive layer (101) are formed into one body; A positive electrode active material (3) is coated on the positive electrode metal conductive layer (102); A negative electrode active material (2) is coated on the negative electrode metal conductive layer (101); A positive electrode tab (22) connected to the positive electrode metal conductive layer (102); The negative electrode tab (21) is connected to the negative electrode metal conductive layer (101).

2. The pole piece composite unit according to claim 1, characterized in that: The pole piece composite unit further comprises an adhesive ring (5), which is attached to the side of the composite current collector (1) where the positive electrode metal conductive layer (102) is located, and is wrapped around the positive electrode active material (3).

3. The pole piece composite unit according to claim 2, characterized in that: The projection of the coating area of ​​the positive electrode active material (3) on the diaphragm (100) is located within the range of the projection of the coating area of ​​the negative electrode active material (2) on the diaphragm (100), the width of the glue coating area between the edge of the coating area of ​​the positive electrode active material (3) and the edge of the coating area of ​​the negative electrode active material (2) is 1 mm to 2 mm, the rubber ring (5) is located within the range of the glue coating area, and the glue width of the rubber ring (5) is smaller than the width of the glue coating area.

4. The pole piece composite unit according to claim 1, characterized in that: The metal material of the positive metal conductive layer (102) and the metal material of the negative metal conductive layer (101) are independent of each other, and the thickness of the positive metal conductive layer (102) and the negative metal conductive layer (101) is 0.2um to 3um.

5. The pole piece composite unit according to claim 1, characterized in that: The material of the positive electrode active material (3) is at least one of lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium manganese oxide, and lithium manganese iron phosphate; the material of the negative electrode active material (2) is at least one of graphite, silicon, lithium metal, and graphite silicon composite material; and the material of the diaphragm (100) is at least one of polyethylene terephthalate, polypropylene, polyethylene, and polytetrafluoroethylene.

6. The pole piece composite unit according to claim 5, characterized in that: The thickness of the positive electrode active material (3) is 100um to 450um, the thickness of the negative electrode active material (2) is 100um to 600um, and the thickness of the diaphragm (100) is 3um to 10um.

7. The pole piece composite unit according to any one of claims 1 to 6, characterized in that: The electrode composite unit further comprises a solid electrolyte (4), and the solid electrolyte (4) is connected to a side of the positive electrode active material (3) away from the composite current collector (1) or a side of the negative electrode active material (2) away from the composite current collector (1).

8. A method for preparing a pole piece composite unit according to any one of claims 1 to 7, characterized in that: include: A composite current collector (1) is prepared, wherein the composite current collector (1) comprises a separator (100), a positive electrode metal conductive layer (102), and a negative electrode metal conductive layer (101), and the separator (100), the positive electrode metal conductive layer (102), and the negative electrode metal conductive layer (101) are formed into one body; coating a positive electrode active material (3) on the positive electrode metal conductive layer (102); coating a negative electrode active material (2) on the negative electrode metal conductive layer (101); Connecting a positive electrode tab (22) to the positive electrode side of the composite current collector (1); A negative electrode tab (21) is connected to the negative electrode side of the composite current collector (1).

9. The method for preparing a pole piece composite unit according to claim 8, characterized in that: The preparation method further comprises: The rubber ring (5) is attached to the positive electrode side of the composite current collector (1) and wrapped around the positive electrode active material (3); A solid electrolyte (4) is prepared on the side of the positive electrode active material (3) or the negative electrode active material (2) away from the composite current collector (1).

10. The method for preparing a pole piece composite unit according to claim 8, characterized in that: When preparing the composite current collector (1), a plurality of composite current collectors (1) are connected via a separator (100), and the preparation method further comprises: After all the pole piece composite units are formed, the plurality of pole piece composite units connected by the diaphragm (100) are cut to form a plurality of independent pole piece composite units.

11. The method for preparing a pole piece composite unit according to claim 8, characterized in that: A composite current collector (1) is prepared, wherein the composite current collector (1) comprises a diaphragm (100), a positive electrode metal conductive layer (102), and a negative electrode metal conductive layer (101), and the steps of forming the diaphragm (100), the positive electrode metal conductive layer (102), and the negative electrode metal conductive layer (101) into one body comprise: A positive electrode metal conductive layer (102) and a negative electrode metal conductive layer (101) are respectively covered on both sides of the diaphragm (100) by a two-step method of magnetron sputtering and vacuum evaporation; After the steps of spraying the positive electrode active material (3) on the positive electrode metal conductive layer (102); and spraying the negative electrode active material (2) on the negative electrode metal conductive layer (101), the method further comprises: Drying the positive electrode active material (3) and the negative electrode active material (2); The dried positive electrode active material (3) and negative electrode active material (2) are rolled to ensure that the positive electrode active material (3) is in close contact with the positive electrode metal conductive layer (102), and the negative electrode active material (2) is in close contact with the negative electrode metal conductive layer (101).

12. An all-solid-state battery, characterized in that: A pole piece composite unit comprising any one of claims 1 to 7.

13. The all-solid-state battery according to claim 12, characterized in that: When the pole piece composite unit includes a rubber ring (5) and a solid electrolyte (4), the all-solid-state battery includes a plurality of stacked pole piece composite units, the layer structure sequence of each pole piece composite unit is the same, and adjacent pole piece composite units are connected via the solid electrolyte (4).

14. The all-solid-state battery according to claim 12, characterized in that: When the pole piece composite unit includes a rubber ring (5), the all-solid-state battery further includes a solid electrolyte (4), the pole piece composite units and the solid electrolyte (4) are alternately arranged and stacked in a sequential stacking manner, the layer structure sequence of each pole piece composite unit is the same, and adjacent pole piece composite units are connected via the solid electrolyte (4).

15. A method for preparing an all-solid-state battery according to claim 12, characterized in that: include: Preparing a plurality of pole piece composite units, wherein the layer structure sequence of each pole piece composite unit is the same; Multiple pole piece composite units are stacked in sequence and then hot pressed into shape; Welding all the positive electrode tabs (22) together; All the negative electrode tabs (21) are welded together to form a battery cell.

16. A method for preparing an all-solid-state battery according to claim 12, characterized in that: include: Preparing a plurality of pole piece composite units, wherein the layer structure sequence of each pole piece composite unit is the same; preparing solid electrolyte (4); Multiple electrode composite units and solid electrolytes (4) are alternately stacked in sequence and then hot-pressed into shape; Welding all the positive electrode tabs (22) together; All the negative electrode tabs (21) are welded together to form a battery cell.

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