Metal battery monomer and preparation method thereof, battery device and power utilization device

Abstract

The invention relates to the technical field of batteries, in particular to a metal battery monomer, a preparation method thereof, a battery device and a power utilization device. Each metal battery monomer comprises a positive pole piece, a negative pole piece, an isolating membrane and electrolyte; wherein the negative pole piece comprises a negative current collector and a gel polymer layer, at least one surface of the negative current collector is laminated with the gel polymer layer, and the gel polymer layer has a hollow structure. According to the metal battery monomer disclosed by the embodiment of the invention, the specific gel polymer layer is formed on the basis of the negative pole piece, so that the safety performance of the battery is further improved on the basis that the battery has good first-effect performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a metal battery monomer, a preparation method thereof, a battery device and a power utilization device. BACKGROUND

[0002] With the vigorous development of new energy vehicles, the battery driving system becomes an important factor affecting the performance and cost of new energy vehicles, and the secondary battery becomes the first choice for power supply in the battery driving system due to the characteristics of high energy density, low memory effect and high working voltage.

[0003] The secondary battery generally comprises a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte. For the metal battery without using carbon / silicon and other embedded negative electrode active materials, the locking liquid capacity of the negative electrode sheet is poor, and the electrolyte is easy to accumulate at the bottom of the battery under the action of gravity, resulting in less electrolyte at the top of the battery, and metal deposition is easy to occur on the negative electrode current collector, thereby promoting dendrite growth. If the reserved space is insufficient, the dendrite growth is easy to pierce the separator and cause short circuit. SUMMARY

[0004] The purpose of the application is to provide a metal battery monomer, a preparation method thereof, a battery device and a power utilization device, aiming at the technical problem of how to improve the safety performance of the metal battery.

[0005] To achieve the above application purpose, the technical scheme adopted by the application is as follows:

[0006] In the first aspect, the application embodiment provides a metal battery monomer, comprising a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte; wherein the negative electrode sheet comprises a negative electrode current collector and a gel polymer layer stacked with at least one surface of the negative electrode current collector, and the gel polymer layer has a hollow structure.

[0007] The gel polymer layer with a hollow structure is stacked on the surface of the negative electrode current collector of the metal battery monomer. Based on the good wettability of the gel state of the gel polymer to the electrolyte, the gel polymer and the electrolyte can lock the electrolyte well after contact. Moreover, the electrolyte is not easy to appear stratification phenomenon during battery storage, and the space structure of the gel polymer layer with a hollow structure can reserve a certain gap space, which is beneficial to alleviate the risk of the negative electrode sheet surface dendrite growth piercing the separator in the cycle process, thereby improving the safety performance of the battery. Therefore, the metal battery monomer of the application embodiment is based on the gel polymer layer with a special structure of the negative electrode sheet, which further improves the safety performance of the battery on the basis of good initial efficiency of the battery.

[0008] In some embodiments, the hollow structure of the gel polymer layer comprises at least one of a network structure, a linear structure and an island structure.

[0009] The aforementioned gel polymer layers of different shapes not only provide a buffer space for metal deposition on the surface of the negative electrode sheet to better reduce the risk of dendrites piercing the separator, but also the combination of such gel polymer layers on the surface of the negative electrode current collector can improve the overall flexibility of the negative electrode sheet, which is more conducive to battery assembly.

[0010] In some embodiments, the gel polymer layer has a mesh structure, and the mesh size in the mesh structure is 1–10 mm; or,

[0011] The gel polymer layer has a linear structure, and the spacing between adjacent lines in the linear structure is 1 to 10 mm.

[0012] The mesh or linear gel polymer layer of the above dimensions can provide sufficient space for metal deposition on the surface of the negative electrode.

[0013] In some embodiments, the thickness of the gel polymer layer is 5–150 μm;

[0014] And / or, the percentage of the gel polymer area on the surface of the negative electrode current collector to the total area of ​​the gel polymer layer is 5-40%.

[0015] The aforementioned thickness of the gel polymer layer provides sufficient space between the positive and negative electrode plates to mitigate the risk of dendrites piercing the separator, while also exhibiting strong electrolyte retention. The gel polymer layer formed by this proportion of gel polymer area demonstrates good electrolyte retention while providing sufficient space for metal deposition, significantly reducing dendrite deposition thickness and thus further minimizing the risk of dendrites piercing the separator.

[0016] In some embodiments, the gel polymer includes at least one of polymethyl methacrylate gel polymer, polyoxyethylene gel polymer, polyacrylonitrile gel polymer, and polyvinylidene fluoride gel polymer.

[0017] The above-mentioned types of gel polymers, when used in negative electrode sheets, can significantly improve the safety performance of batteries.

[0018] In some embodiments, a conductive coating is provided between the negative electrode current collector and the gel polymer layer.

[0019] By adding a conductive coating between the negative electrode current collector and the gel polymer layer, the overall conductivity of the negative electrode sheet can be improved.

[0020] In some embodiments, the conductive coating comprises a conductive carbon layer; and / or,

[0021] The thickness of the conductive coating is 2–20 μm.

[0022] The aforementioned conductive coating can improve the conductivity of the negative electrode.

[0023] Secondly, embodiments of this application provide a method for preparing a metal battery cell, comprising:

[0024] Preparation of polymer slurry;

[0025] The polymer slurry is printed onto at least one surface of the negative electrode current collector using 3D printing technology to form a polymer layer with a hollow structure, thereby obtaining a negative electrode sheet.

[0026] After assembling the negative electrode, positive electrode, and separator into an electrode assembly, an electrolyte is injected to form a gel polymer layer, thus obtaining a metal battery cell.

[0027] By utilizing 3D printing technology and precisely controlling the morphology and spacing of the printing material, a gel polymer layer with a hollow structure is formed on the negative electrode current collector. On one hand, the gel polymer in this layer has excellent electrolyte absorption and retention capabilities; on the other hand, the hollow structure of the gel polymer layer provides a certain gap space, which can effectively provide space for the growth of negative electrode dendrites. Therefore, the metal battery cell prepared in this application, based on the gel polymer layer with a unique structure of the negative electrode sheet, further improves the battery's safety performance while maintaining excellent initial efficiency.

[0028] In some embodiments, the hollow structure of the polymer layer includes at least one of a mesh structure, a linear structure, and an island structure.

[0029] By printing polymer layers of different shapes and structures, and then forming gel polymer layers of corresponding shapes and structures after contact with electrolyte, the resulting metal battery cells not only provide a certain buffer space for metal deposition on the surface of the negative electrode to better reduce the risk of dendrites piercing the separator, but also the gel polymer layer combined with the surface of the negative electrode current collector can improve the overall flexibility of the negative electrode, which is more conducive to battery assembly.

[0030] In some embodiments, the polymer slurry comprises a polymer, a polymeric monomer, and a photoinitiator, wherein the polymeric monomer is a monomer corresponding to the polymer.

[0031] In the polymer slurry, polymer monomers and photoinitiators are added to the polymer base, so that some polymers can be synthesized in situ during the printing process, further improving the overall uniformity and structural controllability of the polymer layer.

[0032] In some embodiments, the polymer includes at least one of polymethyl methacrylate polymer, polyoxyethylene polymer, polyacrylonitrile polymer, and polyvinylidene fluoride polymer.

[0033] The gel polymer layer formed by the above-mentioned polymers can significantly improve the safety performance of the battery.

[0034] In some embodiments, the mass ratio of the polymer to the polymeric monomer is (4:6) to (2:8);

[0035] And / or, the photoinitiator accounts for 4 to 8% of the total mass of the polymer and the polymeric monomer.

[0036] The polymer slurry with the above mass ratio can form a polymer layer in situ very well.

[0037] In some embodiments, the viscosity of the polymer slurry at 25°C is 1500–2000 cps;

[0038] The printing temperature for the polymer slurry is 60–80°C.

[0039] Polymer pastes of the aforementioned viscosity are less prone to clogging, thus improving printing efficiency. Furthermore, the aforementioned temperature allows the polymer paste to form a polymer layer effectively.

[0040] In some embodiments, the conditions of the 3D printing process include:

[0041] (1) The printing speed is 150-200 mm / min;

[0042] (2) The wavelength of the light is 360–370 nm;

[0043] (3) Light intensity is 200–240 mW / cm 2 ;

[0044] (4) Set the illumination time to 60-100s.

[0045] The above printing process parameters enable the polymer slurry to form a polymer layer with a hollow structure.

[0046] Thirdly, embodiments of this application provide a battery device, including a metal battery cell provided in the first aspect of embodiments of this application or a metal battery cell prepared by the preparation method provided in the second aspect of embodiments of this application.

[0047] The battery device, by employing the metal battery cells provided in the embodiments of this application, has good safety performance and can operate better.

[0048] Fourthly, embodiments of this application provide an electrical device, including a metal battery cell provided in the first aspect of this application, a metal battery cell prepared by the preparation method provided in the second aspect of this application, or a battery device provided in the third aspect of this application.

[0049] Electrical devices that employ the metal battery cells or battery devices provided in the embodiments of this application have a long service life and can perform better.

[0050] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0051] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0052] Figure 1 This is a schematic diagram of the battery cell structure according to one embodiment of the battery in this application;

[0053] Figure 2 for Figure 1 The diagram shows an exploded view of a single battery cell.

[0054] Figure 3 This is a schematic diagram of one embodiment of the battery module of this application;

[0055] Figure 4 This is a schematic diagram of one embodiment of the battery pack of this application;

[0056] Figure 5 for Figure 4 The diagram shows the exploded structure of the battery pack.

[0057] Figure 6 This is a schematic diagram of one embodiment of an electrical device that uses a battery as a power source, as described in the present application.

[0058] Figure 7 This is a schematic diagram of the structure of the gel polymer forming a network-like polymer layer in the battery of this application embodiment.

[0059] Explanation of reference numerals in the attached figures:

[0060] 10-Battery cell; 11-Housing casing; 12-Top cover assembly; 13-Electrode assembly; 20-Battery module; 30-Battery pack; 31-Upper casing; 32-Lower casing. Detailed Implementation

[0061] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0062] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0063] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0064] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0065] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0066] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "At least one" refers to one or more (including one, two, three, etc.).

[0067] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0068] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0069] With the dwindling availability of traditional energy resources, the development of new energy storage devices is receiving increasing attention. Among these, secondary batteries have garnered significant interest due to their high energy density, high theoretical capacity, excellent cycle stability, and environmental friendliness. Secondary batteries can be applied not only to energy storage systems in hydropower, thermal power, wind power, and solar power plants, but also widely in electric vehicles such as electric bicycles, electric motorcycles, and electric cars. As the application areas of secondary batteries as power batteries continue to expand, the market demand for them is also constantly increasing.

[0070] A rechargeable battery, also known as a secondary battery, is a battery that can be recharged after discharge to reactivate its active materials and continue to be used. Batteries using liquid electrolytes are also called liquid batteries. Metal batteries, on the other hand, do not use carbon / silicon or other intercalated negative electrode active materials on their negative electrode sheets. Instead, an active metal forms on the surface of the negative electrode sheet after cycling. Examples include lithium metal batteries and sodium metal batteries. Because the negative electrode sheet lacks intercalated negative electrode active materials such as carbon / silicon, metal deposition occurs on the negative electrode current collector, promoting dendrite growth. If there is insufficient space, the dendrites can easily puncture the separator, causing a short circuit and battery failure. Furthermore, metal batteries have a lower electrolyte retention capacity on their negative electrode sheets. Under gravity, the electrolyte tends to accumulate at the bottom of the battery, leading to stratification and bridging of the electrolyte at the top during charge / discharge cycles, resulting in a rapid drop in battery life.

[0071] Based on this, this application embodiment uses 3D printing technology to print a gel polymer layer with a hollow structure on the surface of the negative electrode current collector of the metal battery cell. By utilizing the good wettability and electrolyte retention capacity of the gel polymer, as well as the ability of the gel polymer layer's spatial structure to prevent dendrite puncture risk, the battery performance can be improved. The specific technical solution is as follows.

[0072] Metal battery cells and their preparation methods

[0073] Secondly, this application provides a metal battery cell. Specifically, it includes: (1) a positive electrode sheet, which includes a positive current collector and a positive active layer disposed on at least one surface of the positive current collector, i.e., a positive active layer is disposed on one surface of the positive current collector or both opposite surfaces are disposed on the positive active layer. (2) a negative electrode sheet, disposed opposite to the positive electrode sheet, which includes a negative current collector and a gel polymer layer stacked on at least one surface of the negative current collector, i.e., a gel polymer layer is disposed on one surface of the negative current collector or both opposite surfaces are disposed on the gel polymer layer, and the gel polymer layer has a hollow structure. (3) a separator, located between the positive electrode sheet and the negative electrode sheet, which mainly serves to prevent short circuit between the positive and negative electrodes, and at the same time allows active ions to pass through. (4) an electrolyte, a solution containing an electrolyte, which plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.

[0074] Gel polymers, also known as polymer gels, are systems consisting of a three-dimensional network or interpenetrating network of molecular chains formed through cross-linking polymerization, combined with a solvent, and encompassing both liquid and solid states. Lattice / Perforated structures refer to the mesh-like, linear, or other pores or voids formed within or on the spatial structure of the gel polymer layer. Lattice / Perforated structures typically have repeating geometric shapes, such as squares, circles, and rhombuses. Based on the spatial network structure of the latice / perforated gel polymer layer, it exhibits excellent wettability and electrolyte retention; simultaneously, the gel polymer layer can effectively provide a buffer space for the growth of dendrites on the negative electrode.

[0075] The hollowed-out gel polymer layer can be understood as a gel polymer layer formed by multiple regions without polymer material. On the one hand, the gel polymer in the gel polymer layer has excellent electrolyte absorption capacity; on the other hand, the three-dimensional hollowed-out structure of the gel polymer layer can provide a certain gap space, which can provide space for the growth of negative electrode dendrites. Therefore, the metal battery cell prepared in this application, based on the unique gel polymer layer formed by the negative electrode sheet, not only facilitates capacity utilization and gives the battery excellent first-efficiency performance, but also improves the battery's safety performance. The safety performance is mainly reflected in improved cycle life and storage life.

[0076] In this embodiment of the application, the gel polymer used in the negative electrode sheet can be identified by using infrared spectroscopy, Raman spectroscopy, or nuclear magnetic resonance to determine the corresponding functional groups.

[0077] In this embodiment, the wetting ability of the gel polymer can be characterized by contact testing with the electrolyte. The contact angle refers to the angle between the tangent line at the gas-liquid interface at the gas-liquid-solid three-phase junction and the solid-liquid interface line on the liquid side. The contact angle measuring instrument uses the principle of optical imaging; by manually or automatically dripping the liquid, the volume of each droplet is ensured to be the same, a high-resolution camera ensures optical stability, and the test results are analyzed in real time by measurement software. The results show that the contact angle between the gel polymer and the electrolyte is significantly reduced after it is applied to the surface of the negative electrode.

[0078] In this embodiment, the electrolyte retention capacity of the gel polymer can be assessed by coating the surface of the negative electrode current collector with a gel polymer, then cutting it into squares, and weighing and recording their initial weights using a 10,000-level electronic balance. Both the gel polymer-coated and uncoated current collectors are then immersed in the electrolyte for a period of time, and the weight of the electrodes after immersion is measured. The electrolyte adsorption capacity of different electrodes is calculated, and the magnitude of the electrolyte adsorption capacity is used to characterize the electrolyte retention capacity. The results show that the electrolyte adsorption capacity increases significantly after the gel polymer is applied to the surface of the negative electrode current collector.

[0079] In some embodiments, the perforated structure of the gel polymer layer includes at least one of a mesh structure, a linear structure, and an island structure. These polymer layers of different shapes not only provide a buffer space for metal deposition on the surface of the negative electrode sheet to better reduce the risk of dendrites piercing the separator, but also improve the flexibility of the negative electrode sheet when bonded to the surface of the negative current collector. This makes battery assembly more convenient when the positive electrode sheet, separator, and negative electrode sheet are assembled into a battery.

[0080] In some embodiments, the gel polymer layer has a mesh structure with a mesh size of 1–10 mm; that is, the gel polymer forms multiple strips, which are interwoven to form a mesh with openings; wherein the mesh size is 1–10 mm. Alternatively, the gel polymer layer has a linear structure with a spacing of 1–10 mm between adjacent lines; that is, the gel polymer forms multiple parallel lines with a spacing of 1–10 mm between adjacent lines. The above-described mesh or linear gel polymer layers can provide sufficient space for metal deposition on the surface of the negative electrode, thereby reducing the risk of dendrites piercing the separator.

[0081] In some embodiments, the gel polymer includes at least one selected from polymethyl methacrylate (PMMA)-based gel polymers, polyethylene oxide (PEO)-based gel polymers, polyacrylonitrile (PAN)-based gel polymers, and polyvinylidene fluoride (PVDF)-based gel polymers. The use of these types of gel polymers in the negative electrode can significantly improve the cycle life and storage life of the battery.

[0082] After a gel polymer layer with a hollow structure is set in the negative electrode sheet, the electrolyte solvent comes into contact with the gel polymer layer, forming a gel-like ion channel between the negative electrode sheet and the separator layer. This allows ions to pass through quickly while the gel polymer layer has good mechanical stability and isolation performance, locking the electrolyte inside the gel polymer layer. During long-term storage of the battery, the electrolyte is less likely to seep into the bottom of the battery. During charge and discharge, the risk of battery cycle failure is significantly reduced. At the same time, the hollow structure of the gel polymer layer can provide sufficient space for metal deposition on the surface of the negative electrode sheet, thereby reducing the risk of dendrites piercing the separator.

[0083] It can be used in methyl methacrylate-based gel polymers and polyoxyethylene gel polymers; it has good compatibility in the system, and corresponding battery immersion verification shows that it produces little gas and has little discoloration reaction.

[0084] In some embodiments, the thickness of the gel polymer layer contained in the negative electrode sheet is 5–150 μm; exemplaryly, the thickness of the gel polymer layer can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 130 μm, 140 μm, 150 μm, etc. The gel polymer layer of the above thicknesses can provide sufficient space between the positive and negative electrode sheets to mitigate the risk of dendrites piercing the separator, while also exhibiting strong electrolyte retention capacity.

[0085] In some embodiments, the area of ​​the gel polymer on the surface of the negative electrode current collector accounts for 5% to 40% of the total area of ​​the gel polymer layer. The gel polymer layer has a mesh-like, linear, or island-like structure. The area of ​​the gel polymer on the surface of the negative electrode current collector is the actual space occupied by the gel polymer. The area of ​​the gel polymer layer on the surface of the negative electrode current collector can be understood as the area of ​​the printed area on the surface of the negative electrode current collector. Because there are multiple areas without polymer material in the gel polymer layer, the area of ​​the gel polymer is smaller than the total area of ​​the gel polymer layer. The gel polymer accounts for 5% to 40% of the total area of ​​the gel polymer layer, and the remainder is the area without polymer material in the polymer layer. Exemplarily, the percentage of the gel polymer area to the total area of ​​the gel polymer layer can be 5%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 32%, 35%, 40%, etc. Within this range, it not only has good electrolyte retention capacity but also provides good ion transport channels and sufficient space for metal deposition on the surface of the negative electrode.

[0086] In some embodiments, the gel polymer layer is formed by 3D printing. Specifically, it can be printed using a UV printer (Ultraviolet LED Inkjet Printer). Taking an inorganic sodium metal battery as an example, the polymer slurry is printed onto the negative electrode plate using a 3D printing process. After the electrode is assembled into a cell, liquid is injected to form the gel polymer layer, thus obtaining a metal battery cell.

[0087] In some embodiments, the negative electrode current collector can be a metal foil or a composite current collector. For example, aluminum foil or copper foil can be used as the metal foil. Metal cells are prone to metal deposition on the negative electrode current collector. Due to the high reactivity of metals, dendrite growth is easily caused, and the electrolyte retention capacity is lower. Based on the gel polymer layer with a hollow structure according to the embodiments of this application, the risk of dendrite puncture on the surface of the negative electrode sheet can be effectively reduced.

[0088] In some embodiments, a conductive coating is provided between the negative electrode current collector and the gel polymer layer. By adding a conductive coating to the surface of the negative electrode current collector of the metal battery cell, the conductivity of the battery negative electrode sheet can be further improved.

[0089] In some embodiments, the conductive coating includes a conductive carbon layer; the conductive carbon has excellent conductivity. The thickness of the conductive coating is 2–20 μm, and exemplary thicknesses include 2 μm, 4 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, and 20 μm. The aforementioned conductive coating can better improve the conductivity of the negative electrode.

[0090] The method for preparing the above-mentioned metal battery cell provided in this application includes assembling a positive electrode, a negative electrode, a separator, and an electrolyte into a battery.

[0091] In some embodiments, the step of preparing the positive electrode sheet includes: preparing a positive electrode slurry containing a positive electrode active material, and then coating a film on at least one surface of the positive electrode current collector to obtain a positive electrode active layer.

[0092] In some embodiments, the step of preparing a negative electrode sheet includes: coating at least one surface of the negative electrode current collector with a conductive coating, and then using 3D printing technology to print a polymer slurry on the surface of the conductive coating to form a polymer layer with a hollow structure. The prepared negative electrode sheet is then assembled with a positive electrode sheet, a separator, and an electrolyte to obtain a battery cell. For example, the prepared positive electrode sheet, separator, and negative electrode sheet are stacked sequentially, with the separator acting as a separator between the positive and negative electrode sheets, and then wound to obtain an electrode assembly; the electrode assembly is placed in a battery casing, dried, and then injected with electrolyte, followed by formation and settling processes to obtain a metal battery cell.

[0093] In some embodiments, the positive electrode sheet includes a positive current collector and a positive active layer disposed on at least one surface of the positive current collector, the positive active layer containing a positive active material. Taking a lithium metal battery cell as an example, the positive active material is a lithium-containing material; taking a sodium metal battery cell as an example, the positive active material is a sodium-containing material. As an example, the positive active material of a lithium metal battery cell may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive active materials may also be used. These positive active materials may be used alone or in combination of two or more. The positive active material containing a transition metal element may be a lithium transition metal oxide, examples of which include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. As an example, the positive electrode active material of a sodium metal battery cell may include at least one of sodium layered transition metal oxides, Prussian blue (white) compounds, and polyanionic compounds.

[0094] For the electrolyte, when the battery is a lithium metal battery cell, the corresponding electrolyte is a lithium salt, which can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate. When the battery is a sodium metal battery cell, the electrolyte can be obtained by replacing sodium ions with lithium ions in the above-mentioned electrolyte salts.

[0095] In some embodiments, the positive current collector of the positive electrode sheet may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.

[0096] In some embodiments, the positive electrode active layer of the positive electrode sheet may optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). The positive electrode active layer may also optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the positive electrode active layer may also optionally include other additives, such as dispersants, thickeners (e.g., sodium carboxymethyl cellulose), etc.

[0097] In some embodiments, the type of solvent in the electrolyte is not particularly limited and can be selected according to actual needs. Specifically, it can be an organic solvent, which may include one or more of other types of chain carbonates, cyclic carbonates, and carboxylic acid esters. The types of chain carbonates, cyclic carbonates, and carboxylic acid esters are not specifically limited and can be selected according to actual needs. The organic solvent may also include one or more of diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propionate, ethylene carbonate, propylene carbonate, butenyl carbonate, γ-butyrolactone, methyl formate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, methyl propionate, and tetrahydrofuran.

[0098] In some embodiments, the electrolyte may optionally include other additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0099] In one embodiment, the separator in the battery may be made of materials known in the art for battery separators. As an example, the separator base film may include one or more of polyethylene film, polypropylene film, and polyvinylidene fluoride film.

[0100] Secondly, embodiments of this application provide a method for preparing a metal battery cell. The preparation method of this application includes:

[0101] S01: Preparation of polymer slurry;

[0102] S02: Using 3D printing technology, polymer slurry is printed on at least one surface of the negative electrode current collector to form a polymer layer with a hollow structure, thereby obtaining a negative electrode sheet;

[0103] S03: After assembling the negative electrode, positive electrode and separator into an electrode assembly, an electrolyte is injected to form a gel polymer layer, thus obtaining a metal battery cell.

[0104] The gel polymer layer on the surface of the negative electrode current collector is formed by 3D printing and contact with the injected electrolyte. 3D printing (3DP), also known as additive manufacturing technology (AM), is a technology that manufactures solid parts by adding materials layer by layer based on three-dimensional CAD data. In this embodiment, a three-dimensional model of the gel polymer layer with different shapes (e.g., a hollow structure formed by multiple regions without polymer material) can be designed in advance based on computer-aided modeling software. Then, the polymer slurry can be printed quickly and conveniently to form polymer layers with hollow structures of various shapes. After being assembled into an electrode assembly, it contacts the injected electrolyte to form the gel polymer layer. For example, it can be printed using a UV printer (Ultraviolet LED Inkjet Printer).

[0105] By utilizing 3D printing technology and precisely controlling the morphology and spacing of the printing material, a hollowed-out gel polymer layer is formed on the negative electrode current collector. In the prepared metal battery cell, the hollowed-out gel polymer layer exhibits excellent wettability to the electrolyte. Upon contact with the electrolyte, the gel polymer effectively locks in the electrolyte, resulting in excellent initial performance and reducing the likelihood of electrolyte stratification during battery storage. Furthermore, the spatial structure of the multiple polymer-free regions within the gel polymer layer allows for the reservation of space, mitigating the risk of dendrite growth on the negative electrode surface piercing the separator during cycling, thereby improving battery safety.

[0106] In some embodiments, the perforated structure of the printed polymer layer includes at least one of a mesh structure, a linear structure, and an island structure.

[0107] In this way, upon contact with the injected electrolyte, the gel polymer layer of the negative electrode sheet can form at least one of the following structures: a network structure, a linear structure, or an island structure. For example, a gel polymer layer can be formed in the negative electrode sheet, where the gel polymer forms multiple strips that are interwoven to form a network structure with pores; or, the gel polymer layer can form multiple strips that are parallel to each other, forming a linear gel polymer layer with multiple parallel lines. The arrangement of the multiple strips is not particularly limited and can be along the length or width direction of the negative electrode sheet; or, the gel polymer layer can form multiple identical or different island shapes in the negative electrode sheet, without contact between them. These shapes can be obtained by pre-designing various three-dimensional models of the gel polymer layer using computer-aided modeling software.

[0108] By printing gel polymer layers of different shapes, not only can a certain buffer space be provided for metal deposition on the surface of the negative electrode sheet to better reduce the risk of dendrites piercing the separator, but such gel polymer layers combined with the surface of the negative electrode current collector can improve the overall flexibility of the negative electrode sheet, which is more conducive to battery assembly.

[0109] In some embodiments, the polymer slurry includes a polymer, a polymeric monomer, and a photoinitiator, wherein the polymeric monomer is the monomer corresponding to the polymer. For example, the polymer includes a polymethyl methacrylate-based polymer, where the corresponding polymeric unit is methyl methacrylate; the polymer includes a polyoxyethylene-based polymer, where the corresponding polymeric monomer can be ethylene oxide; the polymer includes a polyacrylonitrile-based polymer, where the corresponding polymeric monomer can be acrylonitrile; and the polymer includes a polyvinylidene fluoride polymer, where the corresponding polymeric monomer can be vinylidene fluoride. By adding polymeric monomers and a photoinitiator to the polymer slurry, some polymers can be synthesized in situ during the printing process, further improving the overall uniformity and structural controllability of the polymer layer.

[0110] In some embodiments, the polymer includes at least one selected from polymethyl methacrylate-based polymers, polyethylene oxide polymers, polyacrylonitrile-based polymers, and polyvinylidene fluoride polymers. The gel polymer layer formed by these polymers further enhances the battery's safety performance while maintaining its initial efficiency.

[0111] In some embodiments, the mass ratio of polymer to monomer is (4:6) to (2:8); for example, the mass ratio of polymer to monomer is 4:6, 3:7, 2:8, etc.; polymer slurries with this mass ratio can form polymer layers well in situ.

[0112] In some embodiments, the photoinitiator accounts for 4 to 8% of the total mass of the polymer and the monomers. The photoinitiator at the above mass ratio can effectively initiate the in-situ formation of a polymer layer from the polymer slurry.

[0113] In some embodiments, the viscosity of the polymer slurry at 25°C is 1500–2000 cps; polymer slurries with this viscosity are less prone to clogging, thus improving printing efficiency. For example, a certain proportion of polymer and monomer are mixed and continuously stirred (speed set to 400–700 r / min) until homogeneous, and then mixed evenly with a photoinitiator (mass ratio of 4–8%) to obtain a 3D printing polymer slurry. The prepared polymer slurry has a viscosity of 1500–2000 CPS at 25°C.

[0114] In some embodiments, the printing temperature for the polymer slurry is 60–80°C. At this temperature, the polymer slurry can form a polymer layer well.

[0115] In some embodiments, the 3D printing process conditions are as follows: printing speed is 150–200 mm / min; illumination wavelength is 360–370 nm; illumination intensity is 200–240 mW / cm². 2 The illumination time is set to 60–100 seconds. These printing process parameters ensure that the polymer slurry forms a good polymer layer.

[0116] For example, by setting the above printing process parameters in the 3D printing equipment, drawing the required 3D printing area on the operating system, the prepared polymer slurry is quickly sprayed from the nozzle onto the surface of the negative electrode current collector, the electrode is transferred to the photocuring zone, and the 3D printing gel polymer slurry is cured under the above parameter conditions to prepare a 3D printed polymer layer. After being assembled into an electrode assembly, it comes into contact with the injected electrolyte to form a gel polymer layer.

[0117] [Battery Device]

[0118] Thirdly, embodiments of this application provide a battery device. The battery device of this application includes a metal battery cell provided in the first aspect of this application or a metal battery cell prepared by the preparation method provided in the second aspect of this application. By employing the metal battery cell provided in this application, the battery device exhibits good charging and discharging performance and safety performance, enabling it to operate more effectively.

[0119] The battery device provided in this application embodiment can be a secondary battery device, including any one of battery cell, battery module, and battery pack. The battery cell refers to a metal battery cell prepared by the preparation method provided in the first aspect of this application embodiment or a metal battery cell provided in the second aspect of this application embodiment, including a battery casing and a cell encapsulated within the battery casing. The shape of the battery cell is not particularly limited; it can be cylindrical, square, or any other arbitrary shape. Figure 1 The shown is a square-structured battery cell 10.

[0120] In some embodiments, such as Figure 2 As shown, the outer packaging of the battery cell 10 may include a housing 11 and a top cover assembly 12. The housing 11 may include a bottom plate and side plates connected to the bottom plate, the bottom plate and side plates enclosing a receiving cavity. The housing 11 has an opening communicating with the receiving cavity, and the top cover assembly 12 is used to cover the opening to close the receiving cavity. The positive electrode sheet, separator, and negative electrode sheet contained in the secondary battery of this application embodiment may be formed into an electrode assembly 13 by a winding process and / or a stacking process. The electrode assembly 13 is encapsulated in the receiving cavity. Electrolyte is immersed in the electrode assembly 13. The number of electrode assemblies 13 contained in the battery cell 10 may be one or more, which can be adjusted according to actual needs.

[0121] The method for preparing the battery cell 10 is well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form the battery cell 10. As an example, the positive electrode, the separator, and the negative electrode can be formed into an electrode assembly 13 by a winding process or a stacking process. The electrode assembly 13 is placed in an outer packaging, dried, and then injected with an electrolyte. After vacuum sealing, settling, formation, and shaping processes, the battery cell 10 is obtained.

[0122] A battery module is assembled from the battery cell 10, which means it can contain multiple battery cells 10. The specific number can be adjusted according to the application and capacity of the battery module.

[0123] In some embodiments, Figure 3 This is a schematic diagram of battery module 20 as an example. (See diagram for example.) Figure 3 As shown, in the battery module 20, multiple battery cells 10 can be arranged sequentially along the length of the battery module 20. Of course, they can also be arranged in any other manner. Furthermore, the multiple battery cells 10 can be fixed in place using fasteners.

[0124] Optionally, the battery module 20 may also include a housing with a receiving space in which multiple battery cells 10 are received.

[0125] A battery pack refers to an assembly of the aforementioned battery cells 10, meaning it can contain multiple battery cells 10. These multiple battery cells 10 can be assembled into the aforementioned battery module 20. The specific number of battery cells 10 or battery modules 20 contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0126] As in the example, Figure 4 and Figure 5 This is a schematic diagram of a battery pack 30 as an example. The battery pack 30 may include a battery compartment and multiple battery modules 20 disposed within the battery compartment. The battery compartment includes an upper compartment 31 and a lower compartment 32. The upper compartment 31 covers the lower compartment 32, forming a closed space for accommodating the battery modules 20. The multiple battery modules 20 can be arranged in any manner within the battery compartment.

[0127] Electrical appliances

[0128] Fourthly, embodiments of this application also provide an electrical device. The electrical device of this application includes a metal battery cell provided in the first aspect of this application, a metal battery cell prepared by the preparation method provided in the second aspect of this application, or a battery device provided in the third aspect of this application. By employing the metal battery cell or battery device provided in the embodiments of this application, the electrical device has a long service life and can operate more effectively.

[0129] Electrical devices can be, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. The type of electrical device can be selected from individual battery cells, battery modules, or battery packs according to its usage requirements.

[0130] Figure 6 This is a schematic diagram of an example electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the device's requirements for high power and high energy density, a battery pack or battery module can be used.

[0131] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use rechargeable batteries as their power source.

[0132] Example

[0133] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0134] Example 1

[0135] Sodium metal battery cells and their preparation

[0136] 1.1 Sodium metal batteries include:

[0137] The system comprises a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode active material is sodium iron pyrophosphate. The negative electrode includes a copper foil and a conductive carbon layer and a perforated gel polymer layer sequentially disposed on the surface of the copper foil. The perforated gel polymer layer is formed by 3D printing into a mesh structure of crisscrossing lines (see reference...). Figure 7 The polymer material is polymethyl methacrylate (PMMA).

[0138] 1.2 The preparation methods of sodium metal batteries include:

[0139] (1) Preparation of the positive electrode sheet:

[0140] Sodium iron pyrophosphate (the positive electrode active material), carbon nanotubes (the conductive agent), and metahexafluorophosphate (the binder) were thoroughly mixed in N-methylpyrrolidone (NMP) at a mass ratio of 95:2:3 to form a uniform positive electrode slurry. This slurry was then coated onto the surface of an aluminum foil current collector. After drying, cold pressing, and die-cutting, a positive electrode sheet with a thickness of 200 μm was obtained. The coating weight of the positive electrode film on the positive electrode sheet was 200 mg / 1540 mm². 2 .

[0141] (2) Preparation of negative electrode sheet:

[0142] After coating a 10μm conductive carbon layer onto the surface of the negative electrode current collector copper foil, a polymer layer is printed on top of the conductive carbon layer, as follows:

[0143] 3D printing slurry preparation: Mix methyl methacrylate (MMA) and polymethyl methacrylate (PMMA) in a mass ratio of 7:3, heat to 60°C, and stir (speed set to 400-700 r / min) until PMMA is completely dissolved in MMA. Then mix with photoinitiator TPO (photoinitiator accounts for 5% of the mass concentration of the former mixture) to obtain 3D printing polymer slurry with a viscosity of 1500-2000 CPS at 25°C.

[0144] 3D printing steps:

[0145] a. Place the 3D printing polymer slurry into the material tank of the 3D printing equipment, and control the temperature at 60℃.

[0146] b. Set the light wavelength of the 3D printing equipment to 365nm and the light intensity to 220mW / cm². 2 The photocuring time was set to 60 seconds, the single-layer printing height was set to 120 μm, the mesh printing line spacing was controlled to 1 mm, and the printing speed was set to 200 mm / min.

[0147] c. Cut the negative electrode current collector copper foil coated with conductive carbon layer to a fixed size of 300*107mm, and fix it to the 3D printing mounting plate using wrinkle adhesive.

[0148] d. Draw the required 3D printing area on the 3D printing equipment's operating system. The 3D equipment then begins the printing operation: the prepared polymer slurry is rapidly sprayed from the nozzle onto the conductive coating surface of the negative electrode current collector, and then transferred to the photocuring zone, where it is cured at the specified wavelength to form a 3D printed polymer layer. After single-sided 3D printing is complete, the operation is repeated to print the other side.

[0149] (3) Separator: Commercial PE coated separator.

[0150] (4) Electrolyte:

[0151] In an argon-filled glove box with a water content of <1ppm, diethylene glycol dimethyl ether and tetrahydrofuran were mixed at a mass ratio of 1:3, sodium hexafluorophosphate (NaPF6) was added, and the mixture was stirred until homogeneous to obtain an electrolyte with a sodium hexafluorophosphate concentration of 1.0 mol / L.

[0152] (5) Assembly:

[0153] The positive electrode, separator, and negative electrode obtained in the above steps are stacked in sequence, with the separator positioned between the positive and negative electrode. The stacked components are then wound to obtain an electrode assembly. The electrode assembly is placed in a housing, dried, and then injected with electrolyte to form a gel polymer layer from the 3D-printed polymer layer. After formation and settling processes, a sodium metal battery cell is obtained.

[0154] Examples 2-8

[0155] Differences from Example 1: See Table 2 for details.

[0156] Comparative Example 1

[0157] The difference between this comparative example and Example 1 is that no polymer is printed on the surface of the negative electrode current collector.

[0158] Comparative Example 2

[0159] The difference between this comparative example and Example 1 is that the polymer is directly coated on the surface of the negative electrode current collector to form a polymer layer (without a mesh-like perforated structure).

[0160] Performance testing

[0161] 1. First-time effectiveness test

[0162] The metal battery cell was charged at 25°C at a rate of 0.33C to a voltage of 3.65V, and the initial charge capacity C1 was measured. Then it was discharged at a rate of 0.33C to a voltage of 1.5V, and the initial discharge reversible capacity D1 was measured. The ratio of D1 to C1 is the battery's initial efficiency.

[0163] 2. Cyclic performance test

[0164] The metal battery cell was charged at 25°C at a rate of 0.33C to a voltage of 3.65V, and then discharged at a rate of 0.33C to a voltage of 1.5V. The reversible capacity was measured as C0. This charging and discharging process was repeated until the discharge capacity Cn / C0 ≤ 80% in a certain cycle. The total number of cycles is denoted as X-Cycle, where Cn is the reversible capacity at the nth cycle.

[0165] 3. Storage performance test

[0166] The metal battery cell was charged at 25°C at a rate of 0.33C to a voltage of 3.65V, and then discharged at a rate of 0.33C to a voltage of 1.5V. The reversible capacity was measured as C0. The battery cell was then stored at 25°C and charged at a rate of 0.33C to a voltage of 3.65V every 30 days, and then discharged at a rate of 0.33C to a voltage of 1.5V. The reversible capacity was measured as Cn. The storage life degradation rate of the battery cell was obtained by dividing Cn by C0. This storage and charging / discharging cycle was repeated until the discharge capacity Cn / C0 ≤ 80% in a certain cycle. The number of storage days Dn was recorded.

[0167] The test results are as follows:

[0168] (1) First-effect of different electrolyte injection coefficients

[0169] Table 1 shows the first-efficiency performance of different electrolyte injection coefficients in Example 1. The electrolyte injection coefficient is calculated as the mass of electrolyte injected into the battery cell / the capacity of the battery cell = g / Ah. It can be clearly seen from the data in Table 1 that the first-efficiency performance continuously improves with the increase of electrolyte injection volume.

[0170] Table 1

[0171] Note injection factor 4.5 g / Ah 5.0 g / Ah 5.5 g / Ah Example 1 first effect 86％ 88％ 92.5％

[0172] (2) The results of the tests conducted in each embodiment with an injection coefficient of 5.5 g / Ah are shown in Table 2.

[0173] Table 2

[0174]

[0175] The area percentage refers to the percentage of the contact area between the gel polymer and the conductive carbon layer to the total area of ​​the printed gel polymer layer.

[0176] The data in Table 2 shows that:

[0177] Comparative Example 1, lacking a printed gel polymer layer in its metal battery cell, exhibited low electrolyte retention capacity in the entire negative electrode, leading to electrolyte deficiency. Furthermore, the limited number of ion channels between the negative and positive electrodes facilitated sodium dendrite growth, resulting in a cycle life of only approximately 300 Cls at 25°C. After 300 Cls, the cycle life plummeted. Disassembly revealed delamination of the negative electrode at the top due to electrolyte deficiency. Additionally, Comparative Example 1's storage life at 25°C was only 180 Days. Comparative Example 2, lacking a three-dimensional perforated structure in its coated gel polymer layer, showed limited improvement in cycle count and storage days for its metal battery cell. In contrast, the embodiments of this application, with their uniquely structured gel polymer layer, significantly improved both cycle count and storage days.

[0178] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A metal battery cell, characterized in that, It includes a positive electrode, a negative electrode, a separator, and an electrolyte; wherein the negative electrode includes a negative current collector and a gel polymer layer stacked on at least one surface of the negative current collector, and the gel polymer layer has a hollow structure.

2. The metal battery cell as described in claim 1, characterized in that, The hollow structure of the gel polymer layer includes at least one of a mesh structure, a linear structure, and an island structure.

3. The metal battery cell as described in claim 2, characterized in that, The gel polymer layer has a mesh structure, and the mesh size in the mesh structure is 1-10 mm; or, The gel polymer layer has a linear structure, and the spacing between adjacent lines in the linear structure is 1 to 10 mm.

4. The metal battery cell according to any one of claims 1-3, characterized in that, The thickness of the gel polymer layer is 5–150 μm; And / or, the percentage of the gel polymer area on the surface of the negative electrode current collector to the total area of ​​the gel polymer layer is 5-40%.

5. The metal battery cell according to any one of claims 1-4, characterized in that, The gel polymer includes at least one of polymethyl methacrylate gel polymer, polyoxyethylene gel polymer, polyacrylonitrile gel polymer, and polyvinylidene fluoride gel polymer.

6. The metal battery cell according to any one of claims 1-5, characterized in that, A conductive coating is provided between the negative electrode current collector and the gel polymer layer.

7. The metal battery cell as described in claim 6, characterized in that, The conductive coating includes a conductive carbon layer; and / or, The thickness of the conductive coating is 2–20 μm.

8. A method for preparing a metal battery cell, characterized in that, include: Preparation of polymer slurry; The polymer slurry is printed onto at least one surface of the negative electrode current collector using 3D printing technology to form a polymer layer with a hollow structure, thereby obtaining a negative electrode sheet. After assembling the negative electrode, positive electrode, and separator into an electrode assembly, an electrolyte is injected to form a gel polymer layer, thus obtaining a metal battery cell.

9. The preparation method according to claim 8, characterized in that, The hollow structure of the polymer layer includes at least one of a mesh structure, a linear structure, and an island structure.

10. The preparation method according to claim 8 or 9, characterized in that, The polymer slurry comprises: a polymer, a polymeric monomer, and a photoinitiator, wherein the polymeric monomer is the monomer corresponding to the polymer.

11. The preparation method according to claim 10, characterized in that, The polymer includes at least one of polymethyl methacrylate polymer, polyoxyethylene polymer, polyacrylonitrile polymer, and polyvinylidene fluoride polymer.

12. The preparation method according to claim 10 or 11, characterized in that, The mass ratio of the polymer to the monomer is (4:6) to (2:8); And / or, the photoinitiator accounts for 4 to 8% of the total mass of the polymer and the polymeric monomer.

13. The preparation method according to any one of claims 8-12, characterized in that, The viscosity of the polymer slurry at 25°C is 1500–2000 cps; The printing temperature for the polymer slurry is 60–80°C.

14. The preparation method according to any one of claims 8-13, characterized in that, The conditions for the 3D printing process include: (1) The printing speed is 150-200 mm / min; (2) The wavelength of the light is 360–370 nm; (3) Light intensity is 200–240 mW / cm 2 ; (4) Set the illumination time to 60-100s.

15. A battery device, characterized in that, Includes the metal battery cell as described in any one of claims 1-7 or the metal battery cell prepared by the preparation method described in any one of claims 8-14.

16. An electrical appliance, characterized in that, Includes the metal battery cell as described in any one of claims 1-7, the metal battery cell prepared by the preparation method described in any one of claims 8-14, or the battery device as described in claim 15.

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