Battery monomer, battery device, power utilization device and preparation process

Abstract

The invention relates to a battery monomer, a battery device, a power utilization device and a preparation process. At least two electrode assemblies are sequentially stacked in the thickness direction; each electrode assembly comprises a first current collector layer, a positive electrode active layer, a solid electrolyte layer, a negative electrode active layer and a second current collector layer which are stacked in the thickness direction; wherein the first current collector layer and the second current collector layer are made of the same material; in two adjacent electrode assemblies, the second current collector layer of the previous electrode assembly and the first current collector layer of the next electrode assembly share the same structural layer, so that the electrode assemblies are electrically connected in series; the first current collector layer and the second current collector layer are formed by pressing nickel powder. The battery monomer, the battery device, the power utilization device and the preparation process provided by the embodiment of the invention have the advantage of high output voltage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery device, a power utilization device and a preparation process. BACKGROUND

[0002] In recent years, from the development of market situation, the application of battery devices is more and more extensive. The battery devices are not only applied to energy storage power systems such as hydroelectric, thermal, wind and solar power stations, but also widely applied to electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of battery devices, the market demand is also increasing.

[0003] The battery device often includes a plurality of battery monomers in series and parallel connection, and the battery monomer includes a plurality of electrode assemblies. In the prior art, the output voltage of the battery monomer is often low, which cannot meet the use requirement. SUMMARY

[0004] Therefore, it is necessary to provide a battery monomer, a battery device, a power utilization device and a preparation process to solve the problem of low output voltage.

[0005] The first aspect of the embodiment of the present application provides a battery monomer, which comprises:

[0006] at least two electrode assemblies arranged in sequence along the thickness direction; each of the electrode assemblies comprises a first current collector layer, a positive active layer, a solid-state electrolyte layer, a negative active layer and a second current collector layer arranged in sequence along the thickness direction;

[0007] The first current collector layer and the second current collector layer are made of the same material.

[0008] The second current collector layer of the previous electrode assembly and the first current collector layer of the next electrode assembly are shared as the same structure layer in the adjacent two electrode assemblies, so that the electrode assemblies are electrically connected in series.

[0009] The first current collector layer and the second current collector layer are both formed by pressing nickel powder.

[0010] By stacking the at least two electrode assemblies in sequence along the thickness direction, and setting the first current collector layer and the second current collector layer to be made of the same material, the second current collector layer of the previous electrode assembly and the first current collector layer of the next electrode assembly are shared as the same structural layer in the adjacent two electrode assemblies, so that the electrode assemblies can be directly electrically connected in series, which can effectively shorten the internal running distance of the battery monomer, reduce the internal resistance of the battery monomer, especially suitable for solid-state battery system, can improve the lithium ion transmission efficiency and reduce the interface side reaction, and effectively improve the output voltage of the single battery monomer; on the other hand, it can eliminate the additional connecting parts and heterogeneous material interface in the traditional series connection, thereby significantly improving the current carrying uniformity of the battery monomer; in addition, since it is not necessary to set the tab structure on each current collector of the electrode assembly as in the traditional battery structure, the battery monomer of the embodiment of the application can effectively optimize the internal space and reduce the weight of the battery monomer, so as to improve the energy density of the battery monomer; in addition, when the first current collector layer and the second current collector layer formed by pressing nickel powder contact the positive active layer and the negative active layer at the same time, the surface is not easy to cause continuous oxidation-reduction reaction or form high impedance interface layer, which fundamentally avoids the interface side reaction, capacity attenuation or safety risk caused by the asymmetric electrochemical behavior of the current collector material, and provides the battery monomer with inherent interface stability basis; therefore, the first current collector layer and the second current collector layer made of the same nickel material can work stably in the bipolar series structure at the same time, ensure that the electrode assemblies are directly electrically connected in series, effectively shorten the internal running distance of the battery monomer, and reduce the internal resistance of the battery monomer, improve the lithium ion transmission efficiency and reduce the interface side reaction, and finally effectively improve the output voltage of the single battery monomer.

[0011] In one of the embodiments, in one of the electrode assemblies, the projections of the positive active layer and the negative active layer on the first current collector layer in the thickness direction coincide with each other. By setting the projections of the positive active layer and the negative active layer on the first current collector layer in the thickness direction to coincide with each other, the complete alignment of the positive active layer and the negative active layer in the planar projection is achieved, forming a stack form of zero OH form. On the one hand, it can ensure that the stress on the edges of each layer is uniform during the subsequent powder die casting or high-pressure compaction process, effectively avoiding the problem of shear stress concentration caused by the traditional design of "negative electrode larger than positive electrode", thereby preventing the material at the edges of each layer structure from breaking and powder falling off, and further ensuring the structural integrity and mechanical stability of the interfaces of the positive active layer, the solid electrolyte layer, the negative active layer, and the like. On the other hand, the complete overlap of the projections of the positive active layer and the negative active layer can eliminate redundant areas and maximize the utilization efficiency of the internal space of the battery monomer, which is helpful to achieve higher volumetric energy density. In addition, the symmetrical and accurately aligned structure is beneficial to forming a uniform current density distribution during the charging and discharging process of the battery, thereby improving the uniformity of the electrode reaction and the cycle life of the battery.

[0012] In one of the embodiments, the projections of the positive active layers in each of the electrode assemblies in the thickness direction coincide with each other; the projections of the negative active layers in each of the electrode assemblies in the thickness direction coincide with each other. By setting the projections of the positive active layers in each of the electrode assemblies in the thickness direction to coincide with each other, and the projections of the negative active layers in each of the electrode assemblies in the thickness direction to coincide with each other, i.e., the projection areas of all positive active layers in the thickness direction are the same in size, and the projection areas of all negative active layers in the thickness direction are the same in size, the accurate alignment of all electrode assemblies in the stacking direction is achieved, so that a highly regular and periodic stack array is formed inside the entire battery monomer. On the one hand, during the powder die casting or lamination assembly process, since the size and position of the positive active layer and the negative active layer of each layer are completely consistent, the process alignment difficulty can be greatly simplified, the production consistency and yield are improved, and large-scale manufacturing is facilitated. On the other hand, from the perspective of electrochemistry, this structure ensures that the migration path of lithium ions in the thickness direction has high consistency, the reaction area and current distribution of all series-connected units are uniform, and the problems of current density concentration or uneven reaction caused by local projection misalignment are avoided, thereby being beneficial to improving the overall capacity of the battery monomer, the rate performance, and the cycle life.

[0013] In one of the embodiments, the electrode assembly comprises a conductive functional layer; the first current collector layer is coated with the conductive functional layer on the side facing the positive active layer. By arranging the conductive functional layer between the first current collector layer and the positive active layer, the conductive functional layer can form a close contact with the first current collector layer pressed from the nickel powder, thereby significantly reducing the contact resistance between the two, and thus optimizing the efficiency of the first current collector layer in supplying electrons to the positive active layer.

[0014] In one of the embodiments, the electrode assembly is in a cylindrical or square column shape as a whole.

[0015] In one of the embodiments, the thickness D1 of the first current collector layer is 5-30 um in the thickness direction; the thickness D5 of the second current collector layer is 5-30 um in the thickness direction.

[0016] In one of the embodiments, the thickness D2 of the positive active layer is 40-400 um in the thickness direction; the thickness D3 of the solid-state electrolyte layer is 40-400 um in the thickness direction; the thickness D4 of the negative active layer is 40-400 um in the thickness direction.

[0017] In one of the embodiments, the density of the positive active layer is not less than 2.5 g / ml.

[0018] In one of the embodiments, the first current collector layer of the electrode assembly at the most leading end is configured as the positive electrode of all the electrode assemblies arranged in series; the second current collector layer of the electrode assembly at the most trailing end is configured as the negative electrode of all the electrode assemblies arranged in series.

[0019] In one of the embodiments, the battery cell comprises a housing; all the electrode assemblies are accommodated in the housing.

[0020] In one of the embodiments, the battery cell comprises two electrode terminals, one of which is arranged at one end of the shell along the thickness direction and is electrically connected to the first current collector layer of the electrode assembly at the most front end; the other electrode terminal is arranged at the other end of the shell along the thickness direction and is electrically connected to the second current collector layer of the electrode assembly at the most rear end. By arranging the two electrode terminals at the two ends of the shell along the thickness direction X and directly electrically connecting them to the first current collector layer at the most front end and the second current collector layer at the most rear end of the stack, the positive and negative current collectors at the two ends of the stack formed by the stacking of all the electrode assemblies are directly connected to the two electrode terminals as the current collection and output ports, and form a current loop, thereby completely eliminating the independent tab, adapter sheet and corresponding welding process, simplifying the structure, reducing the process complexity and manufacturing cost. In addition, the longest current conduction path in the battery cell is the thickness of the stack along the thickness direction X, which can minimize the current path and optimize the current distribution, thereby further reducing the overall internal resistance of the battery cell and improving the rate performance and power density.

[0021] The second aspect of the embodiments of the present application provides a battery device comprising the battery cell described above.

[0022] The third aspect of the embodiments of the present application provides a power utilization device comprising the battery device described above.

[0023] The fourth aspect of the embodiments of the present application provides a preparation process applied to the battery cell described above; the preparation process comprises:

[0024] uniformly laying the current collector powder;

[0025] casting the current collector powder at a first preset pressure for a first preset time to form the first current collector layer;

[0026] uniformly laying the conductive functional powder on the first current collector layer;

[0027] casting the conductive functional powder at a second preset pressure for a second preset time to form the conductive functional layer;

[0028] uniformly laying the positive active material powder on the conductive functional layer;

[0029] casting the positive active material powder at a third preset pressure for a third preset time to form the positive active layer;

[0030] uniformly laying the solid-state electrolyte powder on the positive active layer;

[0031] pressing the solid electrolyte powder for a fourth preset time under a fourth preset pressure to form the solid electrolyte layer;

[0032] uniformly laying negative active material powder on the solid electrolyte layer;

[0033] pressing the negative active material powder for a fifth preset time under a fifth preset pressure to form the negative active layer.

[0034] The above description is only a summary of the technical solutions of the present application. In order to make the technical means of the present application more clear, the present application can be implemented according to the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The structural schematic diagram of the vehicle is provided for some embodiments of the present application.

[0036] Figure 2 The exploded structural schematic diagram of the battery device is provided for some embodiments of the present application.

[0037] Figure 3 The structural schematic diagram of the battery module is provided for some embodiments of the present application.

[0038] Figure 4 The exploded structural schematic diagram of the battery monomer is provided for some embodiments of the present application.

[0039] Figure 5 The schematic diagram of the series structure of multiple electrode assemblies is provided for some embodiments of the present application.

[0040] Figure 6 The schematic diagram of the series structure of multiple electrode assemblies is provided for some embodiments of the present application. Figure 5 The projection schematic diagram of the structure along the thickness direction is shown.

[0041] Figure 7 The projection schematic diagram of the structure along the thickness direction is shown. Figure 5 The projection schematic diagram of the structure along the thickness direction is shown.

[0042] Figure 8 The flowchart of the preparation process is provided for some embodiments of the present application.

[0043] BRIEF DESCRIPTION OF DRAWINGS

[0044] Vehicle - 1000;

[0045] Battery device - 100, case - 110, first portion - 111, second portion - 112, battery module - 120, battery cell - 121, end cap - 122, housing - 123, outer shell - 124, electrode terminal - 125, controller - 200, motor - 300;

[0046] Electrode assembly - 400, first current collector layer - 410, positive active layer - 420, solid-state electrolyte layer - 430, negative active layer - 440, second current collector layer - 450, thickness direction - X. DETAILED DESCRIPTION

[0047] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0049] In the description of the embodiments of the present application, if these technical terms "first", "second", etc. appear, these terms are only for the purpose of description, to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0050] In this paper, the term "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment that is not mutually exclusive with other embodiments. The skilled person in the art explicitly and implicitly understands that the embodiments described herein can be combined with other embodiments.

[0051] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents a "or" relationship between the front and rear associated objects.

[0052] In the description of the embodiments of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two (including two), for example, two, three, etc., unless otherwise explicitly specified and limited. Similarly, if the term "multiple groups" appears, "multiple groups" refers to two groups or more (including two groups), and if the term "multiple pieces" appears, "multiple pieces" refers to two pieces or more (including two pieces).

[0053] In the description of the embodiments of the present application, if these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear, the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0054] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, if technical terms such as "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be understood in a broad sense. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0055] In the present application, unless otherwise explicitly specified and limited, if the first feature is described as "on" or "under" the second feature and the like, it can mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0056] It is to be noted that when an element is referred to as being "on" or "connected to" another element, it can be directly on the other element or intervening elements can be present. In addition, the term "connected" as used herein means the element that can be directly or indirectly connected to the other element and can be electrically connected to the other element. As used herein, the terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar terms are intended for purposes of illustration only and are not intended to be limiting.

[0057] At present, from the development of market situation, the application of battery device is more and more extensive. The battery device is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely applied to electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of battery device, the market demand is also increasing.

[0058] In the related art, the battery monomer is usually assembled into an electrode assembly (bare cell) by winding or laminating the positive electrode sheet, the negative electrode sheet and the separator, then put into the shell, and finally obtained by injecting electrolyte. Among them, each positive electrode sheet and each negative electrode sheet are correspondingly provided with positive and negative electrode tabs for outputting or inputting electric energy, and a plurality of positive electrode sheets are connected in parallel through the positive electrode tabs and connected to the positive electrode of the battery device, and a plurality of negative electrode sheets are connected in parallel through the negative electrode tabs and connected to the negative electrode of the battery device. However, the output voltage of such battery monomer is generally low, the application range is narrow, and the running distance inside the battery monomer is long, which causes the internal resistance of the battery monomer to be large, thereby resulting in poor use performance of the battery monomer.

[0059] In order to alleviate the problem of low output voltage of the battery monomer, at least two electrode assemblies can be stacked in sequence along the thickness direction, and the first current collector layer and the second current collector layer are made of the same material. In the adjacent two electrode assemblies, the second current collector layer of the upper electrode assembly and the first current collector layer of the lower electrode assembly share the same structure layer. In this way, on the one hand, the electrode assemblies can be directly connected in series, thereby effectively shortening the internal running distance of the battery monomer, reducing the internal resistance of the battery monomer, and effectively increasing the output voltage of the single battery monomer; on the other hand, the additional connecting parts and heterogeneous material interfaces in the traditional series connection can be eliminated, thereby significantly improving the current carrying uniformity of the battery monomer.

[0060] The embodiments of the present application provide a battery monomer, a battery device, a power consumption device and a preparation process. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, an energy storage product and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric automobile toy, an electric ship toy and an electric aircraft toy and the like, the spacecraft can include an airplane, a rocket, a space shuttle and a spacecraft and the like, and the energy storage product can include an energy storage station and the like.

[0061] It should be understood that the technical solutions described in the embodiments of the present application are not only limited to the battery device and the power consumption device described above, but can also be applied to all battery devices including a box body and power consumption devices using the battery device, but for the sake of brevity of description, a power consumption device of the embodiments of the present application is taken as a vehicle 1000 for example.

[0062] Please refer to Figure 1 , Figure 1 A structural schematic diagram of the vehicle 1000 is provided for some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile and the like. The vehicle 1000 is internally provided with a battery device 100, which can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000, for example, the battery device 100 can be used as an operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation and driving.

[0063] In some embodiments of the present application, the battery device 100 can not only be used as an operating power supply of the vehicle 1000, but also be used as a driving power supply of the vehicle 1000, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1000.

[0064] Figure 2 An exploded view of the battery device 100 is provided for some embodiments of the present application; Figure 3 A structural schematic diagram of a battery module is provided for some embodiments of the present application. Please refer to Figure 2 and Figure 3 In order to meet different power consumption demands, the battery device 100 can include a plurality of battery monomers 121 and a box body 110, and the battery monomer 121 refers to the smallest unit constituting a battery module 120 or a battery device. The plurality of battery monomers 121 can be connected in series and / or parallel through electrode terminals to be applied to various application occasions.

[0065] The box 110 is used to accommodate the battery monomer 121 or the battery module 120 to avoid the influence of liquid or other foreign matters on the charging or discharging of the battery monomer 121. The box 110 can adopt various structures. In some embodiments, the box 110 can include a first part 111 and a second part 112, the first part 111 and the second part 112 are mutually covered, and the first part 111 and the second part 112 jointly define an accommodation space for accommodating the battery monomer 121. The second part 112 can be a hollow structure with one end open, and the first part 111 can be a plate-shaped structure, which covers the open side of the second part 112 to jointly define the accommodation space with the second part 112; the first part 111 and the second part 112 can also be hollow structures with one side open, and the open side of the first part 111 covers the open side of the second part 112. Of course, the box 110 formed by the first part 111 and the second part 112 can be various shapes, such as a simple solid structure of a single cuboid or a cylinder or a sphere, or a complex solid structure composed of a single cuboid or a cylinder or a sphere, and the embodiments of the present application are not limited thereto. The material of the box 110 can be an alloy material such as aluminum alloy or iron alloy, or a high polymer material such as polycarbonate or polyisocyanurate foam plastic, or a composite material such as glass fiber and epoxy resin, and the embodiments of the present application are not limited thereto.

[0066] In the embodiments of the present application, the plurality of battery monomers 121 can directly form a battery device, or first form a battery module 120, and then the battery module 120 forms the battery device 100. Specifically, the plurality of battery monomers 121 can be directly connected in series, parallel or mixed connection to form a whole, and then the whole formed by the plurality of battery monomers 121 is accommodated in the box 110. Alternatively, the plurality of battery monomers 121 can first be connected in series, parallel or mixed connection to form a battery module 120, and then the plurality of battery modules 120 are connected in series, parallel or mixed connection to form a whole, which is accommodated in the box 110.

[0067] The battery device 100 can further include other structures, for example, the battery device 100 can further include a current collecting component for realizing the electrical connection between the plurality of battery monomers 121.

[0068] Each battery monomer 121 can be a secondary battery device or a primary battery device; it can also be a lithium-sulfur battery device, a sodium-ion battery device or a magnesium-ion battery device, but is not limited thereto. The battery monomer 121 can be a cylinder, a flat body, a cuboid or other shapes, etc. Figure 3 In some embodiments, the battery monomer 121 can be a square lithium-ion battery, Figure 5 In some embodiments, the battery monomer 121 can be a cylindrical lithium-ion battery.

[0069] Please refer toFigure 4 , Figure 4 A decomposition structure diagram of a battery cell 121 is provided for some embodiments of the present application. The battery cell 121 comprises a housing 124, an electrode assembly 400, and other functional components, wherein the housing 124 is used to accommodate the electrode assembly 400.

[0070] The housing 124 can comprise an end cap 122 and a shell 123.

[0071] The end cap 122 refers to a component that covers the opening of the shell 123 to isolate the internal environment of the electrode assembly 400 from the external environment. Without limitation, the shape of the end cap 122 can be adapted to the shape of the shell 123 to fit the shell 123. Alternatively, the end cap 122 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cap 122 is not easily deformed when subjected to extrusion and collision, enabling the battery cell 121 to have higher structural strength and safety performance. The material of the end cap 122 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specially limited in the embodiments of the present application. In some embodiments, an insulating piece can also be provided on the inner side of the end cap 122, which can be used to isolate the electrical connection components in the shell 123 from the end cap 122 to reduce the risk of short circuit. Exemplarily, the insulating piece can be plastic, rubber, etc.

[0072] The shell 123 is a component used to fit the end cap 122 to form the internal environment of the battery cell 121, wherein the formed internal environment can be used to accommodate the electrode assembly 400 and other components. The shell 123 and the end cap 122 can be independent components, and an opening can be provided on the shell 123, and the end cap 122 is covered on the opening to form the internal environment of the battery cell 121. Without limitation, the end cap 122 and the shell 123 can also be integrated, specifically, the end cap 122 and the shell 123 can form a common connecting surface before other components enter the shell, and when it is necessary to seal the inside of the shell 123, the end cap 122 is covered on the shell 123. The shell 123 can be various shapes and sizes, such as cuboid, cylinder, hexagonal prism, etc. Specifically, the shape of the shell 123 can be determined according to the specific shape and size of the electrode assembly 400. For example, if the electrode assembly 400 is a cylindrical structure, a cylindrical shell can be selected; if the electrode assembly 400 is a cuboid structure, a cuboid shell can be selected. The material of the shell 123 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specially limited in the embodiments of the present application.

[0073] The battery cell 121 can further include functional components of the electrode terminals 125 as the positive / negative electrode, which can be used to electrically connect with the electrode assembly 400 for outputting or inputting the electric energy of the battery cell 121. Specifically, the electrode terminal 125 as the positive electrode and the electrode terminal 125 as the negative electrode can be insulatively mounted on the end cover 122, i.e., both the electrode terminal 125 as the positive electrode and the electrode terminal 125 as the negative electrode are not electrically connected with the end cover 122, and both the electrode terminal 125 as the positive electrode and the electrode terminal 125 as the negative electrode are used to electrically connect with the electrode assembly 400 as the positive output pole and the negative output pole of the battery cell 121. Of course, in other embodiments, the electrode terminal 125 as the positive electrode and the electrode terminal 125 as the negative electrode can also be mounted on the housing 123.

[0074] It can be understood that the shell is not limited to the above structure, and the shell can also be other structures, for example, the shell includes the housing 123 and two end covers 122, the housing 123 is a hollow structure with two opposite openings, and one end cover 122 corresponds to cover one opening of the housing 123 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 400. In this structure, the electrode terminal 125 as the positive electrode and the electrode terminal 125 as the negative electrode can be mounted on the same end cover 122, or can be mounted on two end covers 122 respectively.

[0075] In some embodiments, the end cover 122 can also be provided with a pressure relief mechanism for relieving the internal pressure when the internal pressure or temperature of the battery cell 121 reaches a threshold value.

[0076] The electrode assembly 400 is a component in which an electrochemical reaction occurs in the battery cell 121. One or more electrode assemblies 400 can be contained in the housing 123. The electrode assembly 400 has a positive active material layer and a negative active material layer for chemical reactions to occur, and mainly relies on the movement of metal ions between the positive active material layer and the negative active material layer to work.

[0077] Figure 5 A schematic diagram of a series structure of multiple electrode assemblies provided for some embodiments of the present application. Figure 6 For Figure 5 A schematic diagram of the projection of the structure shown in the thickness direction. Figure 7 For Figure 5 A schematic diagram of the projection of the structure shown in the thickness direction. Figure 8 A flowchart of a preparation process provided for some embodiments of the present application.

[0078] Reference Figures 1 to 8As shown, the first aspect of the present application provides a battery cell 121. The battery cell 121 comprises at least two electrode assemblies 400. All the electrode assemblies 400 are sequentially stacked along the thickness direction X; each electrode assembly 400 comprises a first current collector layer 410, a positive active layer 420, a solid-state electrolyte layer 430, a negative active layer 440 and a second current collector layer 450 which are sequentially stacked along the thickness direction X.

[0079] Among them, the first current collector layer 410 and the second current collector layer 450 are made of the same material. In the adjacent two electrode assemblies 400, the second current collector layer 450 of the previous electrode assembly 400 and the first current collector layer 410 of the next electrode assembly 400 share the same structural layer, so that each electrode assembly 400 is electrically connected in series.

[0080] In the embodiment of the present application, the positive active layer 420 can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc.; correspondingly, the negative active layer 440 can be carbon, silicon, silver or silver-carbon mixture, etc.

[0081] In the embodiment of the present application, the battery cell 121 comprises at least two electrode assemblies 400, which means that the electrode assemblies 400 can be two, three, four, five or more, etc., and the actual setting needs to be accurate, and the present application does not limit this.

[0082] In the embodiment of the present application, in the adjacent two electrode assemblies 400, the second current collector layer 450 of the previous electrode assembly 400 and the first current collector layer 410 of the next electrode assembly 400 share the same structural layer; that is, for the shared second current collector layer 450 / first current collector layer 410, its essence is one structure, and the second current collector layer 450 and the first current collector layer 410 can be replaced with each other in material, property and function, without affecting the performance of the battery cell 121. The two sides of the shared second current collector layer 450 / first current collector layer 410 are the positive active layer 420 and the negative active layer 440.

[0083] For ease of illustration, refer to Figure 5 As shown, the first current collector layer 410 at the top end in the thickness direction X of all the electrode assemblies 400 is defined as the positive current collector, and the second current collector layer 450 at the bottom end in the thickness direction X of all the electrode assemblies 400 is defined as the negative current collector.

[0084] The positive electrode active layer 420 is arranged on one side of the positive electrode current collector facing the negative electrode current collector in the thickness direction X, and the negative electrode active layer 440 is arranged on one side of the second current collector layer 450 adjacent to the positive electrode current collector in the thickness direction X; correspondingly, the negative electrode active layer 440 is arranged on one side of the negative electrode current collector facing the positive electrode current collector in the thickness direction X, and the positive electrode active layer 420 is arranged on one side of the first current collector layer 410 adjacent to the negative electrode current collector in the thickness direction X. In this way, the positive electrode current collector can serve as the positive output electrode of the structure after the series connection of all the electrode assemblies 400, and the negative electrode current collector can serve as the negative output electrode of the structure after the series connection of all the electrode assemblies 400, thereby realizing the output or input of the electric energy of all the electrode assemblies 400.

[0085] The solid-state electrolyte layer 430 simultaneously assumes the dual core functions of ion conductive medium and electron insulating diaphragm. Taking a lithium battery as an example, the solid-state electrolyte layer 430 provides a directional migration channel between the adjacent positive electrode active layer 420 and negative electrode active layer 440 with lithium ions as carriers, which is a necessary ion passage to realize electrochemical reaction. Secondly, as a dense solid barrier, the solid-state electrolyte layer 430 can effectively physically isolate the positive electrode active layer 420 and the negative electrode active layer 440 to prevent direct contact between them and cause electron conduction. The solid-state electrolyte layer 430 can be arranged between the adjacent positive electrode active layer 420 and negative electrode active layer 440 along the thickness direction X, so as to separate the arranged positive electrode active layer 420 and negative electrode active layer 440, i.e. one solid-state electrolyte layer 430 is arranged between the arranged positive electrode active layer 420 and negative electrode active layer 440 in the thickness direction X.

[0086] In the embodiment of the present application, the material of the solid-state electrolyte layer 430 can be lithium lanthanum zirconium oxide, lithium aluminum titanium phosphate, lithium lanthanum titanium oxide, lithium phosphorus sulfur, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride or polypropylene oxide.

[0087] In the embodiments of the present application, at least two electrode assemblies 400 are stacked in sequence along the thickness direction X, and the first current collector layer 410 and the second current collector layer 450 are made of the same material. In the adjacent two electrode assemblies 400, the second current collector layer 450 of the previous electrode assembly 400 and the first current collector layer 410 of the next electrode assembly 400 share the same structure layer. In this way, the electrode assemblies 400 can be directly electrically connected in series. On the one hand, the internal current running distance of the battery monomer 121 can be effectively shortened, and the internal resistance of the battery monomer 121 can be reduced. This is especially suitable for solid-state battery systems, which can improve the lithium ion transmission efficiency and reduce the interface side reaction, and effectively improve the output voltage of a single battery monomer 121. On the other hand, the additional connecting components and heterogeneous material interfaces in the traditional series connection can be eliminated, thereby significantly improving the current carrying uniformity of the battery monomer 121. In addition, since there is no need to set a tab structure on each current collector of the electrode assembly as in the traditional battery structure, the battery monomer 121 of the embodiments of the present application can effectively optimize the internal space and reduce the weight of the battery monomer 121, thereby improving the energy density of the battery monomer 121.

[0088] The first current collector layer 410 and the second current collector layer 450 should be made of the same material, and the material should have good electron (reduction) stability and electron loss (oxidation) stability.

[0089] In related technologies, aluminum and its alloys can form a stable passivation film on the surface under high electrode potential (such as the working condition of the positive electrode of a lithium ion battery), thereby effectively resisting oxidation and corrosion, and are widely used as positive electrode current collectors. However, under a lower negative electrode potential, aluminum can alloy with lithium (a special reduction reaction), which leads to the destruction of the current collector structure and the attenuation of the battery performance. Therefore, aluminum is not suitable for use as a negative electrode current collector material.

[0090] Similarly, copper and its alloys have excellent oxidation resistance (anti-electron loss) under a lower electrode potential (such as the working condition of the negative electrode of a lithium ion battery), and are widely used as negative electrode current collectors. However, under a higher positive electrode potential, copper has insufficient thermodynamic stability and is easily oxidized and dissolved, and the generated copper ions can migrate and be reduced and deposited on the negative electrode side, which brings potential safety hazards such as battery short circuit. Therefore, copper is not suitable for use as a high-voltage positive electrode current collector material.

[0091] Copper is stable on the negative electrode side but is easily oxidized on the high-voltage positive electrode side. Nickel is not prone to continuous redox reaction or the formation of a high-resistance interface layer on the surface when it simultaneously contacts the positive active layer 420 and the negative active layer 440. That is to say, for this same material, the current collector material in the traditional battery cannot be used, that is, the first current collector layer 410 and the second current collector layer 450 cannot be made of copper, silver, aluminum, or their alloys.

[0092] That is to say, the first current collector layer 410 and the second current collector layer 450 in the embodiment of the application cannot be made of a single aluminum / copper material.

[0093] In the related art, some batteries use a copper-aluminum composite foil to make a bipolar composite current collector, so that the positive and negative active layers can be arranged on both sides of a piece of current collector. However, this composite current collector has various defects: first, aluminum and copper are two different metals, and their thermal expansion coefficients, plastic deformation capabilities, and elastic moduli are different, so under a high pressure of several hundred megapascals, the two materials will have uneven plastic flow and deformation at the bonding interface, which will easily lead to delamination, cracking, or the formation of micro gaps. Second, there is a potential difference between aluminum and copper in the internal environment of the battery, especially for traditional batteries using liquid electrolyte, which contain a large amount of trace ion conductors. Even for solid-state batteries using solid-state electrolyte, the above situation cannot be avoided, which will form a micro galvanic corrosion battery at the composite interface, accelerate the interface degradation, and cause the contact resistance to increase sharply or even completely fail.

[0094] Finally, for common metal powder pressing processes, the sintering / pressing behaviors of copper powder and aluminum powder are different, and it is difficult to form a dense and firmly bonded composite layer by one-time pressure casting in the process. Therefore, the copper-aluminum composite foil needs to be integrated by rolling, welding, or bonding with conductive adhesive, which not only has a complex process and high cost, but also the pre-prepared copper-aluminum composite foil belongs to a traditional foil, which cannot realize the interface tight fitting advantage brought by powder pressing, and the composite interface itself is still a weak point under high pressure.

[0095] It should be noted that the battery monomer 121 in the embodiment of the application is a solid-state battery using powder pressing.

[0096] In some possible embodiments, referring to Figures 1 to 8 As shown in the figure, the first current collector layer 410 and the second current collector layer 450 are both formed by pressing nickel powder.

[0097] Nickel has good electron (reduction) stability and electron (oxidation) stability.

[0098] In the embodiments of the present application, when the first current collector layer 410 and the second current collector layer 450 formed by pressing nickel powder simultaneously contact the positive active layer 420 and the negative active layer 440, the surfaces thereof are not prone to sustained oxidation-reduction reaction or the formation of a high impedance interface layer, thereby fundamentally avoiding interface side reactions, capacity attenuation or safety risks caused by the asymmetric electrochemical behavior of the current collector material, and providing an inherent interface stability basis for the battery monomer 121. Thus, the first current collector layer 410 and the second current collector layer 450 made of the same nickel material can simultaneously and stably work in the bipolar series structure, ensuring that each electrode assembly 400 directly realizes electrical series connection, effectively shortening the internal running distance of the battery monomer 121, reducing the internal resistance of the battery monomer 121, improving the lithium ion transmission efficiency and reducing the interface side reactions, and ultimately effectively improving the output voltage of the single battery monomer 121.

[0099] In the related art, solid-state batteries are often prepared by warm isostatic pressing process. However, the warm isostatic pressing equipment is often expensive, with a cost of about 3 million yuan per unit, and low production efficiency, which is a great burden on production cost and production efficiency for the manufacturer.

[0100] In the embodiments of the present application, a powder die casting process is adopted, and by designing a special die casting clamp, a high pressure of 100-1000 MPa can be applied to the stacked nickel powder, active powder and electrolyte powder in the cylindrical cavity / square column cavity directly by using a conventional press, so that the first current collector layer 410 / second current collector layer 450 can be pressed from the nickel powder, and the densification and interface tight combination of each layer can be ensured. Compared with the post-processing densification process of traditional warm isostatic pressing, the process has significant integration and efficiency advantages, which not only greatly shortens the production cycle, reduces the equipment investment and energy consumption cost, but more importantly, the nickel current collector layer formed in situ under high pressure can form a stable interface with the adjacent active layer in a micro-scale tight fit, improving the structural integration and conductive reliability, and realizing efficient and low-cost integrated manufacturing from material to structure.

[0101] It should be noted that the first current collector layer 410 and the second current collector layer 450 formed by in-situ pressing can form a more tight mechanical fit and contact with the adjacent positive active layer 420 or negative active layer 440 in a microscale, greatly reducing the interface contact resistance. More importantly, the first current collector layer 410 and the second current collector layer 450 formed by pressing nickel powder have a three-dimensional interconnected metal conductive network inside, and the electronic conduction capacity is isotropic, which is better than the planar directionality of traditional rolled foils, thereby further improving the current carrying uniformity and efficiency in the thickness direction X of the battery monomer 121.

[0102] In some possible embodiments, reference is made to Figures 1 to 8As shown, in one electrode assembly 400, the projections of the positive active layer 420 and the negative active layer 440 on the first current collector layer 410 along the thickness direction X coincide with each other.

[0103] In the related art, in a liquid lithium ion battery, due to the inevitable size and alignment errors of the electrode sheet in the production, cutting and lamination / winding processes, it is often necessary to set an OH structure (Overhang structure, i.e. negative electrode covering positive electrode), that is, to set the area of the negative active layer to be greater than the area of the positive active layer.

[0104] On the one hand, from the production process, setting the OH structure can provide a process fault tolerance buffer zone to ensure that the positive active layer is completely covered by the negative active layer under any slight misalignment, thereby avoiding the local side reaction or lithium metal precipitation caused by the direct exposure of the positive electrode edge to the electrolyte.

[0105] On the other hand, from the electrochemical principle, when the battery is charged, lithium ions are extracted from the positive electrode and embedded in the negative electrode. If the effective area of the negative electrode for receiving lithium ions is insufficient (i.e. the area of the negative active layer is less than the area of the positive active layer), under fast charging or low temperature conditions, lithium ions may be excessively accumulated in some areas of the negative electrode surface and reduced to metallic lithium, i.e. lithium precipitation. Therefore, setting the OH structure can ensure that the area of the negative active layer is greater than the area of the positive active layer, which is equivalent to providing redundant receiving area and more reaction sites for lithium ion embedding, which helps to uniformize the current distribution and lithium ion flow, thereby significantly reducing the risk of local lithium precipitation, ultimately ensuring the cycle life and safety of the battery.

[0106] It can be considered that the OH structure is obtained by using redundant negative electrode material, sacrificing part of the energy density, and introducing a non-uniform stress interface, etc. to obtain better process feasibility and electrochemical safety.

[0107] In the electrode assembly 400, the projections of the positive active layer 420 and the negative active layer 440 on the first current collector layer 410 in the thickness direction X coincide with each other, the complete alignment of the positive active layer 420 and the negative active layer 440 in the planar projection is realized, and the zero OH form of the stacked form is constructed. On the one hand, it can ensure that the stress on the edges of each layer is uniform in the subsequent powder die casting or high-pressure compaction process, effectively avoiding the shear stress concentration problem caused by the traditional design of "negative electrode greater than positive electrode", thereby preventing the material at the edges of each layer structure (the first current collector layer 410, the positive active layer 420, the solid-state electrolyte layer 430, the negative active layer 440, and the second current collector layer 450) from breaking and powder falling off, and further ensuring the structural integrity and mechanical stability of the interfaces of the positive active layer 420, the solid-state electrolyte layer 430, and the negative active layer 440. On the other hand, the complete overlap of the projections of the positive active layer 420 and the negative active layer 440 can eliminate redundant areas and maximize the utilization efficiency of the internal space of the battery monomer 121, which helps to achieve higher volume energy density. In addition, the symmetrical and accurately aligned structure is beneficial to forming a uniform current density distribution during the charging and discharging process of the battery, thereby improving the uniformity of the electrode reaction and the cycle life of the battery.

[0108] In the electrode assembly 400, the projections of the positive active layer 420 and the negative active layer 440 on the first current collector layer 410 in the thickness direction X coincide with each other, the complete alignment of the positive active layer 420 and the negative active layer 440 in the planar projection is realized, and the zero OH form of the stacked form is constructed. On the one hand, it can ensure that the stress on the edges of each layer is uniform in the subsequent powder die casting or high-pressure compaction process, effectively avoiding the shear stress concentration problem caused by the traditional design of "negative electrode greater than positive electrode", thereby preventing the material at the edges of each layer structure (the first current collector layer 410, the positive active layer 420, the solid-state electrolyte layer 430, the negative active layer 440, and the second current collector layer 450) from breaking and powder falling off, and further ensuring the structural integrity and mechanical stability of the interfaces of the positive active layer 420, the solid-state electrolyte layer 430, and the negative active layer 440. On the other hand, the complete overlap of the projections of the positive active layer 420 and the negative active layer 440 can eliminate redundant areas and maximize the utilization efficiency of the internal space of the battery monomer 121, which helps to achieve higher volume energy density. In addition, the symmetrical and accurately aligned structure is beneficial to forming a uniform current density distribution during the charging and discharging process of the battery, thereby improving the uniformity of the electrode reaction and the cycle life of the battery.

[0109] In some possible embodiments, referring to FIG. 1, the projections of the positive active layers 420 in the thickness direction X coincide with each other in each electrode assembly 400. Figures 1 to 8 As shown in FIG. 1, the projections of the positive active layers 420 in the thickness direction X coincide with each other in each electrode assembly 400.

[0110] The projections of the positive active layers 420 in the thickness direction X coincide with each other in each electrode assembly 400, that is, the projection areas of all the positive active layers 420 in the thickness direction X in the battery monomer 121 are the same.

[0111] The projections of the negative active layers 440 in the thickness direction X coincide with each other in each electrode assembly 400, that is, the projection areas of all the negative active layers 440 in the thickness direction X in the battery monomer 121 are the same.

[0112] By overlapping the projections of the positive active layers 420 in the thickness direction X in each electrode assembly 400 with each other, and overlapping the projections of the negative active layers 440 in the thickness direction X in each electrode assembly 400 with each other, that is, the projection areas of all the positive active layers 420 in the thickness direction X are of the same size, and the projection areas of all the negative active layers 440 in the thickness direction X are of the same size, the accurate alignment of all the electrode assemblies 400 in the stacking direction (that is, the thickness direction X) is realized, so that a highly regular and periodically repeated stack array is formed inside the entire battery monomer 121. On the one hand, during the powder die casting or lamination assembly process, since the size and position of the positive active layer 420 and the negative active layer 440 of each layer are completely consistent, the process alignment difficulty can be greatly simplified, the production consistency and yield are improved, and large-scale manufacturing is facilitated. On the other hand, from the perspective of electrochemistry, this structure ensures that the migration path of lithium ions in the thickness direction X has high consistency, the reaction area and current distribution of all series-connected units are uniform, and the problems of current density concentration or uneven reaction caused by local projection misalignment are avoided, thereby being beneficial to improving the overall capacity performance, rate performance and cycle life of the battery monomer 121. In addition, the fully overlapped stack structure makes the volume change of the battery during charging and discharging more consistent, reduces the internal mechanical stress caused by interlayer misalignment, and enhances the interface stability between the electrode assemblies 400 and the structural integrity of the battery.

[0113] In some possible embodiments, the electrode assembly 400 comprises a conductive functional layer; the side of the first current collector layer 410 facing the positive active layer 420 is coated with the conductive functional layer.

[0114] In the embodiments of the present application, the conductive functional layer is arranged between the first current collector layer 410 and the positive active layer 420, so that the conductive functional layer can form close contact with the first current collector layer 410 formed by nickel powder pressing, significantly reducing the contact resistance between the two, thereby optimizing the electron supply efficiency of the first current collector layer 410 to the positive active layer 420.

[0115] It should be noted that for solid-state batteries, the electronic conductivity of positive active materials (such as ternary materials, lithium iron phosphate, etc.) is generally low, and the introduction of the conductive functional layer can construct an efficient electron path inside the positive active layer 420 and at the interface between the positive active layer 420 and the solid-state electrolyte layer 430, effectively promoting the rapid and uniform distribution of electrons on the positive side during charging and discharging, and effectively improving the charging and discharging performance of the battery monomer 121.

[0116] The conductive functional layer can be formed by pressing conductive carbon powder (such as VGCF). Through the three-dimensional conductive network of the conductive carbon itself, the contact resistance between the first current collector layer 410 and the positive active layer 420 is significantly reduced. In the powder pressing manufacturing process, the addition and pressing of the conductive carbon powder help to maintain good pore connectivity while forming a dense structure, which not only facilitates electron transmission, but also provides an auxiliary path for lithium ion transmission at the solid-solid interface, thereby synergistically improving the overall electrochemical performance of the battery cell 121.

[0117] The shape of the electrode assembly 400 is not particularly limited in the present application, and the electrode assembly 400 can be in a cylindrical shape, a square column shape, or any other shape.

[0118] Figure 4 The electrode assembly 400 in FIG. 4A is a square column structure as an example. Along the thickness direction X, the first current collector layer 410, the positive active layer 420, the solid-state electrolyte layer 430, the negative active layer 440, and the second current collector layer 450 are all square.

[0119] Figure 6 The electrode assembly 400 in FIG. 4B is a cylindrical structure as an example. Along the thickness direction X, the first current collector layer 410, the positive active layer 420, the solid-state electrolyte layer 430, the negative active layer 440, and the second current collector layer 450 are all circular.

[0120] In this way, the structure of the electrode assembly 400 is regular and symmetrical, and its regular shape is adapted to the mold cavity and the height of the pressing head in the powder pressing process. For the electrode assembly 400 to adopt a cylindrical structure, it is uniformly stressed during the powder pressing process, ensuring that it can achieve extremely high internal compaction pressure (500-800 MPa) with a small area of stress surface under a conventional tonnage press, thereby effectively replacing the isostatic pressing process. In addition, the regular shape of the electrode assembly 400 facilitates the smooth demolding of the electrode assembly 400 from the mold block and other tooling after pressing, ensuring the integrity and consistency of the zero OH alignment structure during the manufacturing process, and thus enabling efficient and low-cost integrated die casting molding.

[0121] In some possible embodiments, referring to FIG. 4A, Figures 1 to 8 As shown in FIG. 4A, the thickness D1 of the first current collector layer 410 along the thickness direction X is 5-30 um; and the thickness D5 of the second current collector layer 450 along the thickness direction X is 5-30 um.

[0122] By designing the thickness D1 of the first current collector layer 410 to be 5µm~30µm and the thickness D5 of the second current collector layer 450 to be 5µm~30µm, the first current collector layer 410 and the second current collector layer 450, which are formed by pressing nickel powder, are ensured to have sufficient mechanical strength. They can maintain structural integrity under die-casting pressure of up to 500-800MPa without cracking or excessive deformation, thus ensuring the alignment accuracy and interface stability of the zero-OH stacked structure. At the same time, this thickness minimizes the volume ratio of inactive materials while ensuring extremely low electron transport impedance, which can effectively improve the volumetric energy density of the battery cell 121.

[0123] In some embodiments, the thickness D1 of the first current collector layer 410 can be set to 6µm~20µm; the thickness D5 of the second current collector layer 450 can be set to 6µm~20µm. This moderate thickness is beneficial for achieving rapid and uniform heat conduction and compaction in the powder die casting process, ensuring a dense bond between the current collector layer and the adjacent conductive functional layer and active layer.

[0124] In some possible embodiments, see Figures 1 to 8 As shown, along the thickness direction X, the thickness D2 of the positive electrode active layer 420 is 40um~400um; the thickness D3 of the solid electrolyte layer 430 is 40um~400um; and the thickness D4 of the negative electrode active layer 440 is 40um~400um.

[0125] By limiting the thicknesses D2, D3, and D4 of the positive electrode active layer 420, the solid electrolyte layer 430, and the negative electrode active layer 440 to be 40μm~400μm, it is ensured that the positive electrode active layer 420, the solid electrolyte layer 430, and the negative electrode active layer 440 have sufficient active material loading or ion conduction medium, thus providing the battery with high volumetric capacity and reliable ion transport pathway.

[0126] In some possible embodiments, along the thickness direction X, the thickness D2 of the positive electrode active layer 420 is 50um~300um; the thickness D3 of the solid electrolyte layer 430 is 50um~300um; and the thickness D4 of the negative electrode active layer 440 is 50um~300um.

[0127] By designing the thicknesses of the positive electrode active layer 420, the solid electrolyte layer 430, and the negative electrode active layer 440, it can be highly adapted to the powder die-casting process, so that each powder layer can be fully compacted under high pressure of 500-800MPa, achieving ideal solid-solid interface contact and densification, effectively reducing interface impedance, and ultimately ensuring the performance of the battery cell 121.

[0128] In some possible embodiments, see Figures 1 to 8The density of the positive active layer 420 is not less than 2.5 g / ml.

[0129] In the powder compression process, the electrode assembly 400 is subjected to high pressure of 500-800 MPa, and the positive active layer 420 is compacted to a desired density of not less than 2.5 g / ml, so that the contact area between the active material particles in the positive active layer 420 and between the positive active layer 420 and the conductive functional layer and the solid electrolyte layer 430 is greatly increased, thereby significantly reducing the contact resistance of the solid-solid interface and improving the conduction efficiency of electrons and ions. In addition, by limiting the density of the positive active layer 420 to not less than 2.5 g / ml, the battery monomer 121 can effectively ensure a high volumetric energy density.

[0130] In some embodiments, the density of the positive active layer 420 is not less than 3.2 g / ml.

[0131] In some possible embodiments, referring to Figures 1 to 8 As shown, along the thickness direction X, the first current collector layer 410 of the electrode assembly 400 at the most leading end is configured as the positive electrode of all the electrode assemblies 400 arranged in series, and the second current collector layer 450 of the electrode assembly 400 at the most trailing end is configured as the negative electrode of all the electrode assemblies 400 arranged in series.

[0132] In combination Figure 5 As shown, along the thickness direction X, the first current collector layer 410 of the electrode assembly 400 at the most leading end is configured as the positive electrode of all the electrode assemblies 400 arranged in series, and the second current collector layer 450 of the electrode assembly 400 at the most trailing end is configured as the negative electrode of all the electrode assemblies 400 arranged in series. In this way, the positive electrode current collector and the negative electrode current collector at both ends of the stack formed by the stacking of all the electrode assemblies 400 themselves serve as the current collection and output ports, completely eliminating the need for independent tabs, adapter pieces, and corresponding welding processes. The structural design of the present application can achieve a truly tab-free design, which not only simplifies the structure, reduces the process complexity and manufacturing cost, but also fundamentally eliminates the additional contact resistance and potential failure points introduced by additional connecting components.

[0133] In addition, from the performance of the battery monomer 121, since the longest conduction path of the current inside the battery monomer 121 is the thickness of the stack itself in the thickness direction X, the current path can be maximally shortened and the current distribution can be optimized, thereby further reducing the overall internal resistance of the battery monomer 121, which is beneficial to improving the rate performance and power density. In addition, this direct use of the structural body as the output pole significantly improves the space utilization of the battery monomer 121 and effectively improves the volumetric energy density of the battery monomer 121.

[0134] In some possible embodiments, referring to Figures 1 to 8 As shown, the battery cell 121 comprises a shell 124; all the electrode assemblies 400 are accommodated in the shell 124.

[0135] In some possible embodiments, referring to Figures 5 to 7 As shown, the battery cell comprises two electrode terminals 125.

[0136] One of the electrode terminals 125 is arranged at one end of the shell 124 along the thickness direction X, and the electrode terminal 125 is electrically connected with the first current collector layer 410 of the electrode assembly 400 located at the most front end.

[0137] The other electrode terminal 125 is arranged at the other end of the shell 124 along the thickness direction X, and the electrode terminal 125 is electrically connected with the second current collector layer 450 of the electrode assembly 400 located at the most rear end.

[0138] By arranging the two electrode terminals 125 at the two ends of the shell 124 along the thickness direction X respectively, and directly electrically connecting with the first current collector layer 410 located at the most front end and the second current collector layer 450 located at the most rear end of the stack, the positive electrode current collector and the negative electrode current collector located at the two ends of the stack formed by the stacking of all the electrode assemblies 400 are connected with the two electrode terminals 125 respectively, and form a current loop, thereby completely canceling the independent tab, the adapter piece and the corresponding welding process, so as to simplify the structure, reduce the process complexity and manufacturing cost; in addition, the longest conduction path of the current in the battery cell 121 is the thickness of the stack along the thickness direction X, which can maximize the shortening of the current path and optimize the current distribution, thereby further reducing the overall internal resistance of the battery cell 121, which is beneficial to improving the rate performance and power density.

[0139] It should be noted that the two electrode terminals 125 are located at the central axis positions of the two ends of the shell 124, which can make the current distribution and heat distribution of the battery cell 121 in the charging and discharging process more symmetrical and uniform, thereby improving the stability and safety of the work. In addition, the regular structure of the two-end electrode is particularly suitable for the cylindrical or square cylindrical electrode assembly 400, which not only facilitates the series or parallel integration of the battery cell 121 in the module or battery pack, but also facilitates the corresponding thermal management design of the battery pack, such as providing two-end cooling for the battery cell 121.

[0140] The second aspect of the embodiment of the application provides a battery device 100 comprising at least one battery cell 121 described above.

[0141] A third aspect of the embodiments of the present application provides a power utilization device, comprising the battery device 100 described above, and the battery device 100 is used to provide or receive electric energy.

[0142] A fourth aspect of the embodiments of the present application provides a preparation process, applied to the battery cell 121 described above.

[0143] Participate Figures 1 to 8 As shown in the figure, the preparation process comprises:

[0144] S10, uniformly lay the current collector powder.

[0145] Open the ram (not shown) of the powder die casting (not shown), and uniformly lay the current collector powder at the bottom of the die casting cavity, where the current collector powder can be nickel powder.

[0146] S20, adopt a first preset pressure to die cast the current collector powder for a first preset time to form a first current collector layer 410.

[0147] Insert the ram of the powder die casting, and apply pressure to the ram by using a conventional 25T-40T press to slowly die cast to form the first current collector layer 410. The first preset pressure can be 500Mpa-800Mpa; the first preset time can be 1min-3min, and the ambient temperature can be set to 75-110℃.

[0148] S30, uniformly lay the conductive functional powder on the first current collector layer 410.

[0149] Screw the screw (not shown) into the ram, pull out the ram by the screw, and uniformly lay the conductive functional powder on the first current collector layer 410 in the die casting cavity, and the conductive functional powder can be conductive carbon powder.

[0150] S40, adopt a second preset pressure to die cast the conductive functional powder for a second preset time to form a conductive functional layer.

[0151] Insert the ram of the powder die casting, and apply pressure to the ram by using a conventional 25T-40T press to slowly die cast to form the conductive functional layer. The second preset pressure can be 500Mpa-800Mpa; the second preset time can be 1min-3min, and the ambient temperature can be set to 75-110℃.

[0152] S50, uniformly lay the positive active material powder on the conductive functional layer.

[0153] Screw the screw into the ram, pull out the ram by the screw, and uniformly lay the positive active material powder on the conductive functional layer in the die casting cavity, and the positive active material powder can be ternary / lithium-rich manganese powder.

[0154] S60, the positive active material powder is pressed by a third preset pressure for a third preset time to form the positive active layer 420.

[0155] The pressure head for powder pressing can be pressed by a conventional 25T-40T press, and the pressure head is slowly pressed to form the positive active layer 420. The third preset pressure can be 500Mpa-800Mpa; the third preset time can be 1min-3min, and the ambient temperature can be set to 75-110℃.

[0156] S70, the solid electrolyte powder is uniformly laid on the positive active layer 420.

[0157] The screw is screwed into the pressure head, and the solid electrolyte powder is uniformly laid on the positive active layer 420 in the pressing cavity by pulling out the pressure head. The solid electrolyte powder can be lithium lanthanum zirconium oxide, lithium aluminum titanium phosphate, lithium lanthanum titanium oxide, lithium phosphorus sulfur, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride or polypropylene oxide powder.

[0158] S80, the solid electrolyte powder is pressed by a fourth preset pressure for a fourth preset time to form the solid electrolyte layer 430.

[0159] The pressure head for powder pressing can be pressed by a conventional 25T-40T press, and the pressure head is slowly pressed to form the solid electrolyte layer 430. The fourth preset pressure can be 500Mpa-800Mpa; the fourth preset time can be 1min-3min, and the ambient temperature can be set to 75-110℃.

[0160] S90, the negative active material powder is uniformly laid on the solid electrolyte layer 430.

[0161] The screw is screwed into the pressure head, and the negative active material powder is uniformly laid on the solid electrolyte layer 430 in the pressing cavity by pulling out the pressure head. The negative active material powder can be silver carbon powder.

[0162] S100, the negative active material powder is pressed by a fifth preset pressure for a fifth preset time to form the negative active layer 440.

[0163] The pressure head for powder pressing can be pressed by a conventional 25T-40T press, and the pressure head is slowly pressed to form the negative active layer 440. The fifth preset pressure can be 500Mpa-800Mpa; the fifth preset time can be 1min-3min, and the ambient temperature can be set to 75-110℃.

[0164] Subsequently, the process can continue to return to S10 for cyclic implementation, and finally a plurality of electrode assemblies 400 arranged in series can be obtained.

[0165] Any combination of the technical features in the above-described embodiments can be made. For the sake of brevity, the foregoing description is not intended to be exhaustive or to limit the scope of the application to the precise form disclosed. Modifications and alterations can occur to others upon reading and understanding the disclosure. Accordingly, the scope of the application is intended to be limited only by the appended claims.

[0166] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be construed as limiting the scope of the patent application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A battery cell, characterized by, The battery cell comprises: at least two electrode assemblies (400) are sequentially stacked along a thickness direction (X); each of the electrode assemblies (400) comprises a first current collector layer (410), a positive active layer (420), a solid-state electrolyte layer (430), a negative active layer (440) and a second current collector layer (450) which are sequentially stacked along the thickness direction (X); wherein the first current collector layer (410) and the second current collector layer (450) are made of the same material; in two adjacent electrode assemblies (400), the second current collector layer (450) of the previous electrode assembly (400) and the first current collector layer (410) of the next electrode assembly (400) share the same structure layer, so that each electrode assembly (400) is electrically connected in series; the first current collector layer (410) and the second current collector layer (450) are both formed by pressing nickel powder.

2. The battery cell of claim 1, wherein, In one of the electrode assemblies (400), the projections of the positive active layer (420) and the negative active layer (440) on the first current collector layer (410) along the thickness direction (X) coincide with each other.

3. The battery cell of claim 1, wherein, The projections of the positive active layers (420) in each of the electrode assemblies (400) along the thickness direction (X) coincide with each other. The projections of the negative active layers (440) in each of the electrode assemblies (400) along the thickness direction (X) coincide with each other.

4. The battery cell according to any one of claims 1 to 3, characterized in that, The electrode assembly (400) comprises a conductive functional layer; the side of the first current collector layer (410) facing the positive active layer (420) is coated with the conductive functional layer.

5. The battery cell according to any one of claims 1 to 3, characterized in that, The electrode assembly (400) is in the shape of a cylinder or a square column.

6. The battery cell according to any one of claims 1 to 3, characterized in that, Along the thickness direction (X), the thickness D1 of the first current collector layer (410) is 5-30 um, and the thickness D5 of the second current collector layer (450) is 5-30 um.

7. The battery cell of any one of claims 1 to 3, wherein, Along the thickness direction (X), the thickness D2 of the positive active layer (420) is 40-400 um, the thickness D3 of the solid-state electrolyte layer (430) is 40-400 um, and the thickness D4 of the negative active layer (440) is 40-400 um.

8. The battery cell of any one of claims 1 to 3, wherein, The density of the positive active layer (420) is not less than 2.5 g / ml.

9. The battery cell of any one of claims 1 to 3, wherein, Along the thickness direction (X), the first current collector layer (410) of the electrode assembly (400) at the most front end is configured as the positive electrode of all the electrode assemblies (400) arranged in series, and the second current collector layer (450) of the electrode assembly (400) at the most rear end is configured as the negative electrode of all the electrode assemblies (400) arranged in series.

10. The battery cell of any one of claims 1 to 3, wherein, The battery cell comprises a shell (124); all the electrode assemblies (400) are accommodated in the shell (124).

11. The battery cell of claim 10, wherein, The battery cell comprises two electrode terminals (125), one of which is arranged at one end of the shell (124) along the thickness direction (X) and electrically connected to the first current collector layer (410) of the electrode assembly (400) at the most front end; The other electrode terminal (125) is arranged at the other end of the shell (124) along the thickness direction (X) and electrically connected to the second current collector layer (450) of the electrode assembly (400) at the most rear end.

12. A battery device characterized by comprising: The battery cell as claimed in any one of claims 1 to 11.

13. An electrical device, characterized by The battery device as claimed in claim 12.

14. A manufacturing process for the battery cell according to any one of claims 1 to 11, characterized in that, Comprising: Uniformly laying the current collector powder; Using a first preset pressure to press the current collector powder for a first preset time to form the first current collector layer (410); Uniformly laying the conductive functional powder on the first current collector layer (410); Using a second preset pressure to press the conductive functional powder for a second preset time to form the conductive functional layer; Uniformly laying the positive active material powder on the conductive functional layer; Using a third preset pressure to press the positive active material powder for a third preset time to form the positive active layer (420); Uniformly laying the solid-state electrolyte powder on the positive active layer (420); Using a fourth preset pressure to press the solid-state electrolyte powder for a fourth preset time to form the solid-state electrolyte layer (430); Uniformly laying the negative active material powder on the solid-state electrolyte layer (430); Using a fifth preset pressure to press the negative active material powder for a fifth preset time to form the negative active layer (440).

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