A micro energy storage module and a method for preparing the same

Abstract

The present application discloses a micro energy storage module and a preparation method thereof. The integration level of the micro energy storage module is 150 to 7000 energy storage units (micro batteries or capacitors) per square centimeter; the area of ​​each energy storage unit is 0.01 to 0.5 square millimeters; the distance between adjacent energy storage units is 20 to 100 microns; the output voltage of a single energy storage unit is 1 to 4.5V; and the output voltage of the micro energy storage module is 150 to 31500V.

Description

Technical Field

[0001] The present application relates to a micro energy storage module and a preparation method thereof, and belongs to the field of micro energy storage device manufacturing. Background Art

[0002] Soft robots have many advantages such as full flexibility, adaptability and mobility. They have been applied to complex environmental scenes and play an irreplaceable and important role in community services, intelligent manufacturing and smart cities. However, soft robots with a scale from centimeters to decimeters or actuation from pneumatics, hydraulics, and dielectric elastomers usually require a driving voltage of several kilovolts, while the commercially available kilovolt power switches are bulky. Therefore, most soft robots cannot carry their own power supply and are restricted by the power supply wires. In order to achieve high-performance unconstrained soft robots, the development of low-mass, miniature high-voltage power supplies is particularly important. Due to the low output voltage of a single energy storage device, developing a series of integrated energy storage devices to regulate the voltage of the module is a feasible strategy to meet the urgent requirements of different electronic devices in various applications. However, the traditional integration strategy using external metal wires is not suitable for micro power supplies, especially when the output voltage is large and a large number of storage devices need to be connected. There are serious defects such as inconvenient operation, complicated connection steps, heavy weight, large volume, and incompatible mechanical properties. Therefore, it is very necessary to develop integrated micro integrated energy storage devices for future electronic applications. Compared with traditional micro-supercapacitors and batteries with non-planar stacking geometries, micro-supercapacitors and planar micro-batteries with positive and negative electrodes located in the same plane are more suitable for the construction of integrated high-voltage energy storage modules.

[0003] At present, the construction of integrated high-voltage energy storage modules has made certain progress, but it still faces many technical challenges. The key point is to reduce the characteristic size of the device (i.e., electrode width and electrode spacing) and the spacing between adjacent devices, as well as to ensure the performance uniformity of hundreds or thousands of devices. Summary of the invention

[0004] According to one aspect of the present application, a micro energy storage module is provided, wherein the integration level of the micro energy storage module is 150 to 7000 energy storage units (micro batteries or capacitors) per square centimeter;

[0005] The area of ​​each energy storage unit is 0.01 to 0.5 square millimeters;

[0006] The distance between adjacent energy storage units is 20 to 100 microns;

[0007] The output voltage of a single energy storage unit is 1 to 4.5V;

[0008] The output voltage of the micro energy storage module is 150~31500V.

[0009] According to another aspect of the present application, a method for preparing the above-mentioned micro energy storage module is provided, comprising at least the following steps:

[0010] 1) Mixing raw materials containing electrode materials and photosensitive materials, coating them on the surface of a substrate, and heating and curing them; covering them with an optical mask, exposing and developing them, and obtaining a substrate with a micro energy storage unit having uniform thickness.

[0011] (2) coating a layer of photoresist on the substrate with the micro energy storage unit having uniform thickness obtained in step (1), and forming a photoresist protective layer on the micro device area after exposure and development; placing the substrate with the micro energy storage unit having uniform thickness and the photoresist protective layer in a hydrophobic material for heat treatment to form a hydrophobic coating layer, removing the photoresist protective layer and the hydrophobic coating on the surface of the photoresist by washing with an organic solvent, retaining the hydrophobic coating attached to the spacing area between the micro devices, and forming a patterned hydrophobic layer; coating the electrolyte on the entire module, and the droplets containing the electrolyte will gather in the device area to form electrochemical isolation, thereby obtaining the micro energy storage module.

[0012] The electrode material is selected from at least one of PH1000, graphene or lithium titanate;

[0013] The photosensitive material is selected from polyethylene glycol dimethacrylate and / or sericin-isocyanatoethyl methacrylate;

[0014] The mass ratio of the electrode material to the photosensitive material is 0.1 to 10:1;

[0015] The substrate is selected from at least one of silicon wafer, transparent glass, quartz glass, polyethylene terephthalate film, polymethyl methacrylate film, polyimide film and cellulose film.

[0016] The exposure is ultraviolet light exposure;

[0017] The intensity of the ultraviolet light of the ultraviolet exposure is 5 to 15 mw / cm 2 ; The time is 20 to 100 seconds.

[0018] The thickness of the micro energy storage unit is 0.1 to 200 μm;

[0019] The thickness of the photoresist layer is greater than the thickness of the micro energy storage unit;

[0020] The area of ​​the photoresist protection layer is greater than or equal to the area of ​​the micro energy storage device, but less than the sum of the areas of the hydrophobic coating of the micro energy storage device and the spacing area between the micro devices.

[0021] The coating is performed by spin coating, the spin coating speed is 500 to 3000 rpm / min, and the number of spin coating times is 1 to 5 times.

[0022] The hydrophobic material is selected from at least one of heptadecafluorodecyltrimethoxysilane, perfluoro(1-butenyl vinyl ether) or perfluorotributylamine;

[0023] The temperature of the heating treatment is 50 to 200°C;

[0024] The heating treatment time is 0.5 to 10 hours.

[0025] The organic solvent is selected from one of ethanol, acetone, N,N-dimethylformamide and N-methylpyrrolidone.

[0026] The electrolyte is selected from at least one of 0.5-2M sulfuric acid, 0.5-6M potassium hydroxide, 0.5-21M lithium chloride, 21M lithium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium perchlorate or sodium tetrafluoroborate-1-ethyl-3-methylimidazolium tetrafluoroborate.

[0027] The present invention has the following advantages: a micro energy storage module with high output voltage is proposed, and a preparation process of two-step photolithography combined with hydrophobic treatment is proposed, which solves the problem of small unit scale and high precision of micro devices; solves the uniformity of thousands of integrated devices; solves the problem of accurate positioning and addition of electrolytes to prevent the electrolytes of adjacent devices from bordering each other. Compared with the prior art, this technology has higher precision, streamlined process, more convenient operation and better controllability. The present invention can be widely used in the fields of micro-nano devices such as micro-electromechanical systems, micro-robots, and micro-implantable medical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the micro energy storage module obtained in Example 1.

[0029] Figure 2 for Figure 1 Partial enlarged image.

[0030] Figure 3 Schematic diagram of the base.

[0031] Figure 4 Schematic diagram of coating a layer of electrode / photosensitive composite material on a substrate.

[0032] Figure 5 Schematic diagram of the energy storage module microelectrodes prepared by photolithography.

[0033] Figure 6 A schematic diagram of continuing to coat a layer of photoresist on the energy storage module.

[0034] Figure 7 Schematic diagram of forming a photoresist protection layer on the energy storage device after secondary photolithography.

[0035] Figure 8 Schematic diagram of coating with hydrophobic material.

[0036] Fig. 9 Schematic diagram of a patterned hydrophobic layer.

[0037] Fig.10 Schematic diagram of electrolyte droplets gathering in the device area.

[0038] List of reference numerals: 1. Raw material containing electrode material and photosensitive material; 2. Substrate; 3. Micro energy storage unit; 4. Photoresist; 5. Photoresist protective layer; 6. Hydrophobic coating; 7. Hydrophobic coating attached to the spacer area between micro devices; 8. Electrolyte. DETAILED DESCRIPTION

[0039] Preparation Example

[0040] (1) A raw material 1 containing an electrode material and a photosensitive material is mixed in a mass ratio of 0.1 to 10:1, coated on the surface of a substrate 2, and heated to cure; covered with an optical mask, exposed to ultraviolet light, and developed to obtain a micro energy storage unit 3 with uniform thickness.

[0041] (2) A layer of photoresist 4 is further coated on the substrate 2 with the micro energy storage unit obtained in step (1), and after exposure and development, a photoresist protective layer 5 is formed on the micro device area; the substrate 2 with the micro energy storage unit and the photoresist protective layer is placed in an atmosphere of hydrophobic material for heat treatment to form a hydrophobic coating 6, and the photoresist protective layer and the hydrophobic coating on the surface of the photoresist are cleaned and removed in an organic solvent, and the hydrophobic coating 7 attached to the spacer area between the micro devices is retained to form a patterned hydrophobic layer; an electrolyte 8 is coated on the entire module, and the electrolyte 8 droplets will gather in the device area to form a good electrochemical isolation, thereby obtaining the micro energy storage module.

[0042] Figures 3 to 10 Schematic diagram of the preparation process of the preparation example.

[0043] Example 1

[0044] The electrode active material PH1000 and the photosensitive material SU8 3035 were mixed in a mass ratio of 1:1, and a uniform mixed liquid was prepared by magnetic stirring. The mixed liquid was spin-coated on the silicon wafer substrate at 1000 rpm for 30 s. After pre-baking and cooling, the designed optical mask (such as Figure 1 , Figure 2 As shown, a single device has four electrode fingers, where the electrode width is 50 μm, the length is 200 μm, the electrode spacing is 25 μm, and the single device area is 0.055 square millimeters; the device spacing is 50 μm, and the integration density is 1230 energy storage units (micro batteries or capacitors) / square centimeter), at 10 mW / cm2 After exposure to ultraviolet light for 25s, the energy storage device electrode with a thickness of 80μm was obtained after development in ethyl lactate for 8 minutes. Then continue to spin-coat the photoresist, and after pre-baking, exposure, post-baking and development, a protective layer with a thickness of 90μm is formed on the device area. The entire module is placed in a closed container, 0.5ml of 17fluorodecyltrimethoxysilane is added, and the treatment is added at 70℃ for 6h. After cooling, the photoresist in the device area is washed off with ethanol. The obtained module device electrode area is a hydrophilic area, and the spacer area between the devices is a hydrophobic area. Finally, 1MH2SO4 electrolyte is dripped on the entire module, and the 1M H2SO4 electrolyte droplets gather in the hydrophilic electrode area to form a good electrochemical isolation. The entire module is electrochemically tested, and the output voltage is 700V.

[0045] Figure 1 This is a schematic diagram of the micro energy storage module obtained in Example 1.

[0046] Figure 2 for Figure 1 Partial enlarged image.

[0047] Comparative Example 1

[0048] The electrode active material PH1000 and the photosensitive material SU8 3035 were mixed in a mass ratio of 1:1, and a uniform mixed liquid was prepared by magnetic stirring. The mixed liquid was spin-coated on the silicon wafer substrate at 1000 rpm for 30 s. After pre-baking and cooling, the designed optical mask was covered. Figure 1 , Figure 2 As shown, a single device has four electrode fingers, where the electrode width is 50 μm, the length is 200 μm, the electrode spacing is 25 μm, and the single device area is 0.055 square millimeters; the device spacing is 50 μm, and the integration density is 1230 energy storage units (micro batteries or capacitors) / square centimeter), at 10 mW / cm 2 After exposure to ultraviolet light for 25 seconds and development in ethyl lactate for 8 minutes, the energy storage device electrode with uniform thickness was obtained. 1M H2SO4 electrolyte was directly dripped on the entire module. The electrolyte droplets were distributed on the electrodes of the entire module and could not form a good electrochemical isolation. The entire module was electrochemically tested and the output voltage was only 0.6V.

[0049] Comparative Example 2

[0050] The electrode active material graphene and the photosensitive material polyethylene glycol dimethacrylate were mixed in a mass ratio of 0.5:1, and a uniform mixed liquid was prepared by magnetic stirring. The mixed liquid was spin-coated on a transparent glass substrate at 2000 rpm for 30 s. After pre-baking and cooling, the designed optical mask was covered (a single device has two electrode fingers, where the electrode width is 45 μm, the length is 100 μm, the electrode spacing is 10 μm, and the single device area is 0.01 square millimeter; the device spacing is 20 μm, and the integration is 6944 energy storage units (micro batteries or capacitors) / square centimeter). 2 After exposure to ultraviolet light for 60s, the energy storage device electrode with a thickness of 15μm was obtained after development in weak alkali for 8 minutes. Then continue to spin-coat the photoresist, and after pre-baking, exposure, post-baking and development, a protective layer with a thickness of 20μm is formed on the device area. The entire module is placed in a closed container, 0.5ml of 17-fluorodecyltrimethoxysilane is added, and the treatment is added at 200℃ for 0.5h. After cooling, the photoresist in the device area is washed away with acetone. The obtained module device electrode area is a hydrophilic area, and the spacer area between the devices is a hydrophobic area. Finally, 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte is dripped on the entire module, and the 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte droplets gather in the hydrophilic electrode area to form a good electrochemical isolation. The entire module is electrochemically tested, and the output voltage is 20000V.

[0051] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a micro energy storage module, characterized in that: At least the following steps are included: (1) Mixing raw materials containing electrode materials and photosensitive materials, coating them on the surface of the substrate, and heating and curing them; Covering with an optical mask, exposing and developing, to obtain a substrate with a micro energy storage unit having uniform thickness; (2) coating a photoresist layer on the substrate with the micro energy storage unit of uniform thickness obtained in step (1), and forming a photoresist protective layer on the micro energy storage unit area after exposure and development; placing the substrate with the micro energy storage unit and the photoresist protective layer of uniform thickness in a hydrophobic material for heating treatment to form a hydrophobic coating layer, removing the photoresist protective layer and the hydrophobic coating on the surface of the photoresist by washing with an organic solvent, and retaining the hydrophobic coating attached to the spacer between the micro energy storage units to form a patterned hydrophobic layer; coating the electrolyte on the entire module, and the droplets containing the electrolyte will gather in the micro energy storage unit area to form electrochemical isolation, thereby obtaining the micro energy storage module; The thickness of the photoresist layer is greater than the thickness of the micro energy storage unit; The area of ​​the photoresist protective layer is greater than or equal to the area of ​​the micro energy storage unit, but less than the sum of the areas of the hydrophobic coating of the micro energy storage unit and the spacer between the micro energy storage units; The hydrophobic material is selected from at least one of heptadecafluorodecyltrimethoxysilane, perfluoro(1-butenyl vinyl ether) or perfluorotributylamine; The temperature of the heating treatment is 50-200°C; The heating time is 0.5 to 10 hours.

2. The preparation method according to claim 1, characterized in that: The electrode material is selected from at least one of PH1000, graphene or lithium titanate; The photosensitive material is selected from polyethylene glycol dimethacrylate and / or sericin-isocyanatoethyl methacrylate; The mass ratio of the electrode material to the photosensitive material is 0.1-10:1; The substrate is selected from at least one of silicon wafer, transparent glass, quartz glass, polyethylene terephthalate film, polymethyl methacrylate film, polyimide film and cellulose film.

3. The preparation method according to claim 1, characterized in that: The exposure is ultraviolet light exposure; The intensity of the ultraviolet light of the ultraviolet exposure is 5-15 mw / cm 2 ; Time is 20~100 s.

4. The preparation method according to claim 1, characterized in that: The thickness of the micro energy storage unit is 0.1-200 μm.

5. The preparation method according to claim 1, characterized in that: The coating is performed by spin coating, the spin coating speed is 500-3000 rpm / min, and the number of spin coating times is 1-5 times.

6. The preparation method according to claim 1, characterized in that: The organic solvent is selected from one of ethanol, acetone, N,N-dimethylformamide and N-methylpyrrolidone.

7. The preparation method according to claim 1, characterized in that: The electrolyte is selected from at least one of 0.5-2M sulfuric acid, 0.5-6M potassium hydroxide, 0.5-21M lithium chloride, 21M lithium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium tetrafluoroborate, sodium perchlorate or sodium tetrafluoroborate-1-ethyl-3-methylimidazolium tetrafluoroborate.

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