Preparation method of special-shaped structure solid-state battery with high specific energy and high strength

Abstract

The invention discloses a preparation method of a high-specific-energy and high-strength special-shaped structure solid-state battery, according to the method, a high-strength solid-state structure battery is constructed through collaborative innovation of a material system and structural design, a silane cross-linked microporous gel solid-state electrolyte is adopted in the battery to replace a liquid-state electrolyte, the problem of lithium dendrite puncture is solved, and the high-specific-energy and high-strength special-shaped structure solid-state battery is prepared. A self-adaptive electrode network is constructed by combining a high-strength current collector, so that the stability of the high-strength and high-specific-energy battery is improved, and forming of a special-shaped structure is supported; the outer layer is coated with an insulating carbon fiber / Kevlar fiber reinforced shell, and a high-strength carbon fiber / Kevlar fiber material is adopted as a battery protection and mechanical reinforcement part. Through collaborative optimization of an internal system and an external system, the solid-state structure battery has an energy storage-structure integration function, the space utilization rate of electric equipment is greatly improved, the effective load of the equipment is improved, the safety problems of fire, explosion and the like cannot occur when the battery is broken and punctured by external force, and the weight of the system is reduced by 30% or above by eliminating a redundant structure.

Description

Technical Field

[0001] This invention belongs to the field of energy storage battery technology, and relates to the assembly and preparation process of a high-strength, high-specific-energy structure battery with energy storage and weighing capabilities, specifically to a method for preparing a high-strength, high-specific-energy irregular-shaped structure battery. Background Technology

[0002] The rapid development of electric vehicles and electric aircraft has placed higher demands on battery energy density; however, traditional lithium-ion batteries are gradually approaching their energy density bottleneck. Unlike gasoline-powered vehicles, the battery pack in electric vehicles accounts for a significant portion of the total vehicle weight, directly impacting their driving range. Structural batteries offer a new approach to addressing this technological bottleneck. The material stores electrical energy while simultaneously serving as a structural support for the vehicle body, effectively reducing system weight, simplifying design, and improving system efficiency. By using structural batteries to replace structural components and reduce or completely replace conventional batteries, weight reduction and increased driving range can be achieved while maintaining structural performance. Calculations for electric vehicles show that equipping them with this new structural battery can increase driving range by up to 90%. Structural batteries integrate energy storage and structural components into a single entity, offering significant advantages such as effectively reducing system weight, increasing battery capacity, and optimizing payload space utilization. Summary of the Invention

[0003] To develop key components for solid-state batteries that combine high ionic conductivity and excellent mechanical properties, and to solve the challenge of interface stress matching, this invention provides a method for fabricating high-energy-density, high-strength, irregularly shaped solid-state batteries. This method breaks through the traditional separate design of batteries and structural components, and provides a "mass-negative effect" energy solution for high-end equipment through integrated innovation of materials, structure, and function. This invention achieves a system weight reduction of over 30% by eliminating redundant structures, while improving space utilization efficiency; through synergistic innovation of material systems and structural design, a high-strength solid-state battery structure is constructed. Internally: a silane-crosslinked microporous gel solid electrolyte is used to replace the liquid electrolyte, overcoming the challenge of lithium dendrite penetration; combined with a high-strength current collector, an adaptive electrode network is constructed, achieving improved stability of the high-strength, high-energy-density battery and supporting the molding of irregularly shaped structures. Externally: an outer layer is covered with an insulating carbon fiber / Kevlar fiber reinforced shell, using high-strength carbon fiber / Kevlar fiber materials as battery protection and mechanical reinforcement components. Through the coordinated optimization of internal and external systems, solid-state structure batteries have the function of energy storage-structure integration, which can significantly improve the space utilization rate of electrical equipment, increase the effective load of equipment, and will not cause safety problems such as fire or explosion when subjected to external force fracture or puncture.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A method for fabricating a solid-state battery with a high specific energy and high strength irregular structure, such as... Figure 1 As shown, it includes the following steps:

[0006] Step 1: Dissolve the lithiophilic molecules in DMSO or DMF solvent to obtain a lithiophilic molecule solution, wherein the lithiophilic molecules include, but are not limited to, one or more of the following: cellulose, animal collagen, sodium 3-mercaptopropanesulfonate, sodium polydithiopropanesulfonate, sodium N,N-dimethylthioformamide propanesulfonate, 4,6-dimethyl-2-mercaptopyrimidine, γ-methacryloyloxypropyltrimethoxysilane, quaternary ammonium salts, etc.

[0007] Step 2: Apply the above-mentioned lithium-philic molecule solution to a high-strength conductive material using an immersion, spin-coating, or ultrasonic spraying machine. Allow it to stand to allow the solvent to evaporate, resulting in a high-strength negative electrode current collector. The high-strength conductive material includes, but is not limited to, one of the following: conductive nonwoven fabric, conductive woven fabric, conductive plastic film, graphene fiber, carbon fiber, and metal foil. The substrate of the conductive nonwoven fabric or conductive woven fabric includes, but is not limited to, one of the following: aramid fiber, high-strength polyimide, ultra-high-strength polyethylene, polyethylene, polypropylene, and polyurethane.

[0008] Step 3: Roll the lithium metal onto the high-strength negative electrode current collector to obtain a high-strength flexible composite lithium metal negative electrode;

[0009] Step 4: Coat the positive electrode active material onto the positive electrode current collector to obtain a flexible positive electrode, wherein: the active material is a ternary, lithium cobalt oxide or lithium iron phosphate or other common positive electrode active materials;

[0010] Step 5: Assemble the flexible composite lithium metal anode prepared in Step 3 and the flexible cathode prepared in Step 4 into a pouch cell using a Z-shaped stacking method to obtain a bare cell.

[0011] Step 6: After stacking, the positive and negative electrode tabs are welded together, and the battery cell is encapsulated in a shell with an aluminum-plastic film to obtain a dry battery cell. The battery cell is covered with a high-strength insulating fiber cloth, which includes, but is not limited to, one of glass fiber, Kevlar fiber, ultra-high strength polyethylene fiber, and high-strength polyimide fiber.

[0012] Step 7: Inject gel electrolyte into the dry cell, then vacuum impregnate and seal before heating to solidify, obtaining a high-energy-density flexible solid-state pouch battery cell. The gel electrolyte consists of a gel electrolyte framework and an electrolyte matrix, with a ratio of 1:100 to 1:10. The gel electrolyte framework is prepared by chemical cross-linking polymerization of monomers and silane coupling agents via an initiator, with a ratio of monomers to silane coupling agents of 1:5 to 5:1. The monomer is pentaerythritol tetraacrylate; the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane; the initiator is azobisisobutyronitrile; the electrolyte matrix consists of an electrolyte solvent and a lithium salt; the electrolyte solvent is ethylene glycol dimethyl ether (DME) and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), with a molar ratio of 1:2 to 4; the lithium... The salt is one or more of lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium bis(oxalate-borate) (LiBOB), lithium difluorooxalate-borate (LiODFB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluoroarsenate (LiAsF6), and lithium tetrafluoroborate (LiBF4). The specific preparation method is as follows: Step 1, preparation of electrolyte matrix: mix electrolyte solvent and lithium salt evenly in a glove box to obtain electrolyte matrix; Step 2, preparation of gel electrolyte precursor: add polymerizable monomer and silane coupling agent to the above electrolyte matrix to obtain gel electrolyte precursor; Step 3, preparation of gel electrolyte: add initiator to gel electrolyte precursor, heat and polymerize gel electrolyte precursor to obtain gel electrolyte, control the heating temperature to 60~80℃, and the heating time to 2~48 hours;

[0013] Step 8: Impregnate the fiber in a low-temperature curing epoxy resin to obtain a fiber prepreg, wherein the fiber is carbon fiber or Kevlar fiber.

[0014] Step 9: Apply carbon fiber prepreg to the outer layer of the pouch cell according to its size. Then, pressurize the battery with metal clamps. The pressure range is 0.1~1MPa. After pressurization, transfer the battery to a high-temperature oven for heating. The heating time is 4~48 hours and the heating temperature is 60~130℃ (to increase battery flexibility or reduce curing temperature).

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) High specific energy and high strength: Three-dimensional fibrous electrode / current collector interlayer flexible composite technology overcomes the bottleneck of synergistic optimization of mechanical and electrochemical performance;

[0017] (2) Integrated battery molding: Develop lightweight and high-strength composite shell materials to form an integrated in-situ coating and formation process;

[0018] (3) Flexible irregular shape: Construct a solid-state structure battery with "flexible inside and rigid outside", which has the advantages of adjustable shape, high energy density and high mechanical strength;

[0019] (4) This invention is applicable to large-scale production, providing a practical way for the large-scale application of high-safety lithium metal batteries. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the fabrication process of a high-strength, irregularly shaped solid-state battery.

[0021] Figure 2 Optical photographs of a high-strength, irregularly shaped solid-state battery under load.

[0022] Figure 3 The circuit capacity curve of the structured battery is shown.

[0023] Figure 4 Optical photograph of a structural battery cell.

[0024] Figure 5 Optical photograph of a fiber-reinforced high-strength structural battery. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0026] Example 1:

[0027] Step 1: Preparation of biomimetic gel electrolytes:

[0028] In a glove box, 3.7 g of dimethyl ethylene glycol (DME) was added to a 50 mL glass bottle, followed by 5.6 g of lithium bis(fluorosulfonyl)imide (LiFSI). The mixture was stirred with a magnetic stirrer for 12 h to dissolve the DME. After stirring, 24 g of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) was added, and the mixture was stirred for 12 h to obtain an electrolyte mixture. 0.2 g of γ-methacryloyloxypropyltrimethoxysilane and 0.5 g of pentaerythritol tetraacrylate were added to the electrolyte mixture, and the mixture was stirred for 2 h to obtain a biomimetic gel electrolyte precursor. 0.3% initiator was added to the gel electrolyte precursor, and the mixture was stirred for 10 min for later use.

[0029] Step 2: Fabrication of the structural battery electrode:

[0030] In a drying room with a dew point above -40°C, sodium 3-mercaptopropane sulfonate (MPS) additive was dissolved in DMSO solvent and stirred until homogeneous to obtain a lithiophilic solution. Copper foil was placed in an ultrasonic spraying machine, and the lithiophilic solution was sprayed onto the copper foil. After standing to allow the solvent to evaporate, a lithiophilic current collector was obtained. In the same drying room, a 30µm lithium strip was rolled onto both sides of the copper foil using a roller press. The flexible lithium metal anode was then die-cut into 57mm pieces. A composite lithium metal anode was obtained at a thickness of 126 mm. A positive electrode slurry (positive electrode active material NCM9055: conductive agent Super P: binder PVDF = 97.5:1.5:1) was coated onto an aluminum foil current collector. The coated positive electrode sheet was transferred to a vacuum oven for drying. The dried positive electrode sheet was then die-cut into 55 mm pieces using a die-cutting machine. A 122 mm dimension was used to obtain the positive electrode of the structural battery.

[0031] Step 3: Fabrication of high-energy-density, high-strength irregularly shaped batteries:

[0032] In a drying room with a dew point above -40℃, the positive and negative electrode sheets obtained in step two are used to prepare dry cells using a Z-shaped stacking process. A 16+2+2 double ceramic separator is used. After stacking, the positive and negative electrode tabs are welded, and the battery is vacuum-sealed using aluminum-plastic film. The sealed cell is transferred to a glove box, the dry cell is cut open, and the gel electrolyte precursor from step one is injected into the cell. After vacuum impregnation, it is vacuum-sealed. Optical photographs of the structural battery cell are shown below. Figure 4 As shown. Carbon fiber prepreg is bonded to both sides of the battery cell, and a bent conformal metal clamp is used to pressurize the cell at a pressure of 0.1 MPa. The pressurized battery cell is then transferred to a heating chamber for curing and molding at a temperature of 60–130°C for 10–48 hours. Figure 2 As shown, a load-bearing test was conducted on the conformal battery. The results showed that the battery could work stably and light up an LED light bulb under a 2kg load. Figure 3 As shown, the battery was subjected to charge and discharge tests, and it can be seen that the structural battery can stably cycle for more than 50 times.

[0033] Example 2:

[0034] Step 1: Preparation of biomimetic gel electrolytes:

[0035] In a glove box, 3.7 g of dimethyl ethylene glycol (DME) was added to a 50 mL glass bottle, followed by 5.6 g of lithium bis(fluorosulfonyl)imide (LiFSI). The mixture was stirred with a magnetic stirrer for 12 h to dissolve the DME. After stirring, 24 g of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) was added, and the mixture was stirred for 12 h to obtain an electrolyte mixture. 0.2 g of γ-methacryloyloxypropyltrimethoxysilane and 0.5 g of pentaerythritol tetraacrylate were added to the electrolyte mixture, and the mixture was stirred for 2 h to obtain a biomimetic gel electrolyte precursor. 0.3% initiator was added to the gel electrolyte precursor, and the mixture was stirred for 10 min for later use.

[0036] Step 2: Fabrication of high-strength flexible electrodes:

[0037] Copper-plated aramid textile fibers were dried in a 70℃ vacuum oven for 48 hours. In a drying room with a dew point above -40℃, MPS additives were dissolved in DMSO solvent and stirred until homogeneous to obtain a lithium-affinity solution. The flexible conductive fiber cloth was placed in an ultrasonic spraying machine, and the lithium-affinity solution was sprayed onto the flexible conductive fibers. After standing to allow the solvent to evaporate, a high-strength current collector was obtained. In a drying room with a dew point above -40℃, a 30-micron lithium strip was rolled onto both sides of the textile cloth using a roller press. The flexible lithium metal anode was then die-cut into 57mm pieces. A high-strength flexible lithium metal anode was obtained with a diameter of 126 mm. A positive electrode slurry (positive electrode active material lithium iron phosphate: conductive agent Super P: binder PVDF = 97.5:1.5:1) was coated onto a flexible nickel-plated three-dimensional current collector. The coated positive electrode sheet was transferred to a vacuum oven for drying, and then die-cut into 55 mm pieces using a die-cutting machine. A 122 mm size yields a high-strength, flexible positive electrode.

[0038] Step 3: Fabrication of high-energy-density, high-strength irregularly shaped batteries:

[0039] In a drying room with a dew point above -40℃, the flexible positive and negative electrode sheets obtained in step two are used to prepare dry-cell batteries using a Z-shaped stacking process. A 16+2+2 double ceramic separator is used. (The bare cell is shown in the image.) Figure 4(As shown) After stacking, positive and negative electrode tabs are welded. A 50-micron thick glass fiber cloth is wrapped around both sides of the bare cell, and the battery is vacuum-sealed using an aluminum-plastic film. The sealed cell is transferred to a glove box, the dry cell is cut open, and the gel electrolyte precursor from step one is injected. After vacuum impregnation, it is vacuum-sealed. Carbon fiber prepreg is pasted onto both sides of the cell, and the cell is pressurized using a bent metal clamp, applying a pressure of 0.1 MPa. The pressurized cell is transferred to a heating chamber for curing and molding. The heating temperature is 60~130℃, and the heating time is 10~48h, resulting in a high-strength, high-energy-density irregular-structure battery. A cell photograph is shown below. Figure 5 As shown.

[0040] Example 3:

[0041] The difference between this embodiment and Embodiments 1 and 2 is that: in the gel electrolyte, the ratio of gel skeleton to electrolyte matrix is ​​1:20, the ratio of polymeric monomer to silane coupling agent is 1:1; the molar ratio of ethylene glycol dimethyl ether (DME) to 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) is 1:3; and the lithium salt is lithium perchlorate.

[0042] Example 4:

[0043] The difference between this embodiment and Embodiments 1 and 2 is that: in the gel electrolyte, the ratio of gel skeleton to electrolyte matrix is ​​1:60, the ratio of polymeric monomer to silane coupling agent is 4:1; the molar ratio of ethylene glycol dimethyl ether (DME) to 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) is 1:2; and the lithium salt is lithium tetrafluoroborate.

[0044] Example 5:

[0045] The difference between this embodiment and embodiments 1-4 is that the lithiophilic molecule in the solution is hydroxyethyl cellulose. The high-strength current collector used is a 6-micron perforated PP copper foil.

[0046] Example 6:

[0047] The difference between this embodiment and embodiments 1-4 is that the lithium-loving molecules in the lithium-loving molecule solution are animal collagen. The high-strength current collector used is 20-micron copper-plated PU nonwoven fabric.

[0048] Example 7:

[0049] The difference between this embodiment and Embodiments 1-4 is that the lithiophilic molecule in the solution is γ-methacryloyloxypropyltrimethoxysilane. The high-strength current collector used is a 20-micron copper-plated PU textile fabric.

[0050] Example 8:

[0051] The difference between this embodiment and Embodiments 1-4 is that the lithiophilic molecule in the solution is 4,6-dimethyl-2-mercaptopyrimidine. The high-strength current collector used is a 20-micron copper-plated aramid textile.

[0052] Example 9:

[0053] The difference between this embodiment and Embodiments 1-4 is that the lithium-loving molecule in the solution is sodium polydisulfide dipropane sulfonate. The high-strength current collector used is a 20-micron silver-plated aramid textile.

[0054] Example 10:

[0055] The difference between this embodiment and embodiments 1-4 is that the lithiophilic molecules in the solution are quaternary ammonium salts. The high-strength current collector used is an 80-micron copper-plated glass fiber woven fabric.

[0056] Example 11:

[0057] The difference between this embodiment and embodiments 1-10 is that the external high-strength material is Kevlar fiber material.

Claims

1. A method for preparing a solid-state battery with a high specific energy and high strength irregular structure, characterized in that... The method includes the following steps: Step 1: Dissolve the lithiophilic molecules in DMSO or DMF solvent to obtain a lithiophilic molecule solution; Step 2: Use an immersion, spin coating, or ultrasonic spraying machine to spray the lithium-philic molecule solution onto the high-strength conductive material, let it stand to allow the solvent to evaporate, and obtain a high-strength negative electrode current collector; Step 3: Roll the lithium metal onto the high-strength negative electrode current collector to obtain a high-strength flexible composite lithium metal negative electrode; Step 4: Coat the positive electrode active material onto the positive electrode current collector to obtain a flexible positive electrode; Step 5: Assemble the flexible composite lithium metal anode prepared in Step 3 and the flexible cathode prepared in Step 4 into a pouch cell using a Z-shaped stacking method to obtain a bare cell. Step 6: After stacking the cells, the positive and negative electrode tabs are soldered, and the cells are encapsulated in an aluminum-plastic film to obtain dry cells. Step 7: Inject gel electrolyte into the dry cell, then vacuum the cell for impregnation, seal and heat to solidify, and obtain a high-energy-density flexible solid-state pouch battery cell. Step 8: Impregnate the fibers in a low-temperature curing epoxy resin to obtain fiber prepreg; Step 9: Apply the fiber prepreg to the outer layer of the pouch cell according to its size. Then, press the battery with metal clamps and transfer it to a high-temperature oven for heating.

2. The method for preparing a solid-state battery with high specific energy and high strength irregular structure according to claim 1, characterized in that... In step one, the lithium-loving molecules include one or more of cellulose, animal collagen, sodium 3-mercaptopropanesulfonate, sodium polydithiopropanesulfonate, sodium N,N-dimethylthioformamide propanesulfonate, 4,6-dimethyl-2-mercaptopyrimidine, γ-methacryloyloxypropyltrimethoxysilane, and quaternary ammonium salts.

3. The method for preparing a solid-state battery with high specific energy and high strength irregular structure according to claim 1, characterized in that... In step two, the high-strength conductive material includes one of the following: conductive nonwoven fabric, conductive textile fabric, conductive plastic film, graphene fiber, carbon fiber, and metal foil. The substrate of the conductive nonwoven fabric and conductive textile fabric is one of aramid, high-strength polyimide, ultra-high-strength polyethylene, polyethylene, polypropylene, and polyurethane.

4. The method for preparing a solid-state battery with high specific energy and high strength irregular structure according to claim 1, characterized in that... In step six, the outer side of the battery cell is covered with high-strength insulating fiber cloth.

5. The method for preparing a solid-state battery with a high specific energy and high strength irregular structure according to claim 4, characterized in that... The high-strength insulating fiber cloth includes, but is not limited to, one of glass fiber, Kevlar fiber, ultra-high strength polyethylene fiber, and high-strength polyimide fiber.

6. The method for preparing a solid-state battery with a high specific energy and high strength irregular structure according to claim 1, characterized in that... In step seven, the gel electrolyte is composed of a gel electrolyte skeleton and an electrolyte matrix, wherein the ratio of the gel skeleton to the electrolyte matrix is ​​1:100 to 1:5; the gel electrolyte skeleton is prepared by chemical cross-linking polymerization of polymeric monomers and silane coupling agents through an initiator.

7. The method for preparing a solid-state battery with high specific energy and high strength irregular structure according to claim 6, characterized in that... The ratio of the polymerizable monomer to the silane coupling agent is 1:20 to 20:

1. The polymerizable monomer is pentaerythritol tetraacrylate, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane, and the initiator is azobisisobutyronitrile.

8. The method for preparing a solid-state battery with high specific energy and high strength irregular structure according to claim 6, characterized in that... The electrolyte matrix comprises an electrolyte solvent and a lithium salt. The electrolyte solvent is ethylene glycol dimethyl ether or 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, with a molar ratio of 1:2 to 4. The lithium salt is one or more of lithium perchlorate, lithium hexafluorophosphate, lithium bis(oxalato)borate, lithium difluorooxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluoroarsenate, and lithium tetrafluoroborate.

9. The method for preparing a solid-state battery with high specific energy and high strength irregular structure according to claim 1, characterized in that... In step eight, the fiber is carbon fiber or Kevlar fiber.

10. The method for preparing a solid-state battery with a high specific energy and high strength irregular structure according to claim 1, characterized in that... In step nine, the pressure range is 0.1~1MPa, the heating time is 4~48 hours, and the heating temperature is 60~130℃.

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