A method for 3D printing of energy storage battery fabrics

Abstract

This invention discloses a method for 3D printing to prepare energy storage battery fabric, belonging to the field of secondary batteries and their manufacturing. Addressing the complexity of fiber battery manufacturing and the difficulty in weaving them into fabric, this invention develops a method for directly preparing battery fabric using 3D printing. The method involves 3D printing the electrode layer in a fabric pattern, and then printing the gel electrolyte and encapsulating polymer layer by layer, achieving convenient manufacturing of energy storage fabric. By eliminating the assembly and weaving processes of fiber batteries, the manufacturing complexity is greatly reduced, and the impact of weaving on the battery is avoided. This invention features a simple process, ease of implementation, and provides a new approach to solving the difficulties faced by flexible energy storage fabrics, potentially promoting its further practical application.

Description

Technical Field

[0001] This invention relates to a method for 3D printing to prepare energy storage battery fabric, belonging to the field of secondary batteries and their manufacturing, and is used to conveniently manufacture flexible energy storage battery fabric, realize more wearable energy storage devices, and provide energy for wearable portable electronic devices. Background Technology

[0002] In the development of fiber batteries, the assembly, encapsulation, and fabric integration of fiber batteries represent significant challenges. Reported fiber battery research involves encapsulating the fiber batteries within heat-shrink tubing through a complex assembly process. While this method enables laboratory-scale testing and demonstration of fiber battery devices, its large-scale fabrication is extremely complex and difficult to scale up. Furthermore, in the process of integrating fiber batteries into fiber battery fabrics, given the current mechanical properties and dimensions of fiber batteries, simply using interlacing and weaving methods to integrate them into existing fabrics makes it difficult to achieve higher-density and higher-performance integrated energy storage fabrics. These problems severely hinder the practical production and application of fiber batteries.

[0003] The use of 3D printing technology in fabric manufacturing has already achieved numerous breakthroughs in clothing comfort design, thermal control, wearable sensing, and the medical field. Leveraging its advantages in structural design and precision, 3D printing can prepare and assemble functional materials according to designed fabric structures, realizing the functionalization of fabrics. Applying this characteristic of 3D printing to the preparation of fiber batteries and battery fabrics, enabling electrode fabric printing, electrolyte printing coating, and polymer printing encapsulation, respectively, allows for the direct preparation, assembly, and encapsulation of battery fabrics from the fabric's own formation. This is expected to significantly reduce the assembly and integration difficulties currently faced in fiber electrodes, enabling the convenient preparation of flexible and breathable energy storage fabrics. Summary of the Invention

[0004] (a) Purpose of the invention

[0005] The purpose of this invention is to provide a method for 3D printing to prepare energy storage battery fabrics, thereby solving the technical problems of difficulty in preparing existing fiber batteries and difficulty in integrating them into energy storage fabrics.

[0006] (II) Technical Solution

[0007] To achieve the above objectives and solve the above technical problems, the technical solution of the present invention is as follows:

[0008] A method for 3D printing to prepare energy storage battery fabric, characterized by the following steps:

[0009] Step 1: Printing of Electrode Fabric

[0010] (1) Use composite polymer, multi-walled carbon nanotubes and nanoelectrode active materials, mix them in a mass ratio of 1:1:2, add 5 to 10 times the mass of solid solvent, and dissolve and disperse them evenly by grinding or ball milling to obtain the slurry used for printing electrodes;

[0011] The composite polymer is composed of a two-component polymer and a photoinitiator I2959. Component A is a photocurable polymer, including polyethylene glycol diacrylate and polyethylene glycol dimethacrylate. Component B is a high-viscosity polymer that can be rapidly physically crosslinked, including chitosan, sodium alginate and polyvinylidene fluoride. The mass of component A is 1 to 3 times the mass of component B.

[0012] The active material is used for lithium iron phosphate particles and lithium permanganate particles as the positive electrode, and for lithium titanate particles or lithium titanium phosphate particles as the negative electrode.

[0013] The solvent used is deionized water for chitosan and sodium alginate, and N-methylpyrrolidone for polyvinylidene fluoride;

[0014] (2) After the slurry used for printing the electrode is ultrasonically degassed, it is placed in the syringe of an extrusion-type direct-write 3D printer and printed in a grid pattern. The grid line distance in the printed pattern is greater than or equal to 4 mm, and the extrusion speed during the printing process is 1~2 mm. 3 / s, the printing travel speed is 2~5 mm / s;

[0015] (3) After printing, copper and aluminum tabs are inserted into the unshaped electrodes, and then immersed in the coagulation bath for 10 minutes until the polymer component B in the electrodes is cross-linked and shaped, thus obtaining positive electrode fabric and negative electrode fabric respectively.

[0016] Step 2: Printing and Coating of Gel Electrolytes

[0017] (1) The same components of the composite polymer in step one are used, but the mass of component A is adjusted to 3 to 4 times the mass of component B, the solvent ratio is adjusted to 5 to 8 times the mass of the polymer, and lithium sulfate is added to a concentration of 1 to 2 mol / L. After the polymer and lithium sulfate are dissolved, one-tenth of the polymer mass of vapor-deposited hydrophilic nano silica is added. The mixture is then mixed evenly in a ball mill to obtain a gel electrolyte precursor for printing.

[0018] (2) The gel electrolyte precursor is printed on both sides of the electrode fabric using a 3D printer with the same printing pattern and parameters as the electrode fabric, so that the printed gel electrolyte can cover and wrap the electrode network. During the printing process of the gel electrolyte, the ultraviolet light with a wavelength of 365 nm is continuously irradiated to crosslink the electrode fabric and component A in the gel electrolyte.

[0019] (3) The pre-shaped gel electrolyte after printing and the positive electrode fabric and negative electrode fabric wrapped by it are immersed together in a coagulation bath of 2 mol / L lithium sulfate for 10 min. Component B in the gel electrolyte cross-links to form a whole, and then it is washed with 2 mol / L lithium sulfate solution.

[0020] Step 3: Printing and encapsulating the energy storage fabric

[0021] (1) Mix photocurable polyurethane acrylate and 4% photoinitiator 1173, and add the same mass of polyethylene glycol acrylate monomer as solvent. After stirring and removing bubbles, transfer the mixture into the 3D printer syringe.

[0022] (2) Set the printing extrusion speed to 2~3 mm 3 The printing speed is 3~6 mm / s, and printing is performed on both sides. During the printing process, ultraviolet light is applied to encapsulate the battery on the outer layer of the gel electrolyte, thereby obtaining the energy storage fabric.

[0023] Furthermore, the viscosity of the paste used for printing the electrodes is 10. 2 ~10 4 The viscosity is Pa·s, and decreases with increasing shear rate. Furthermore, the storage modulus is higher than the loss modulus under low shear stress, but becomes lower than the loss modulus after being subjected to a certain shear stress.

[0024] Furthermore, the coagulation bath used is a solution that enables component B in the composite polymer to undergo rapid physical cross-linking; for chitosan, it is a calcium chloride solution, and for chitosan, it is a sodium hydroxide solution.

[0025] Furthermore, after printing the gel electrolyte and printing the encapsulated photocurable polymer, the rapid cross-linking and curing of the polymer encapsulates the material, preventing further flow and blockage of the pores in the mesh electrode fabric, thus preserving the fabric's breathability.

[0026] Furthermore, the prepared energy storage fabric has good flexibility due to the intrinsic flexibility of the electrodes, gel electrolyte, and encapsulating polymer, and can maintain stable charge and discharge performance during bending.

[0027] (III) Effective Returns

[0028] The beneficial effects of this invention are as follows: By using 3D printing technology, the textile process of fabric forming is integrated into the preparation process of electrodes, electrolytes, and encapsulation. This allows for the direct acquisition of battery fabric through a process of printing electrode fabric, followed by gel electrolyte printing and coating, and finally encapsulation printing. This significantly simplifies the preparation process and reduces its complexity, while avoiding the stress and adverse effects of weaving processes on the battery materials themselves. Furthermore, the composition and processing requirements of the printing slurry ensure that the resulting battery possesses good mechanical properties and excellent internal electrochemical reactions and mass transfer processes, thus giving the battery fabric superior energy storage characteristics. This unique and novel manufacturing method, along with the corresponding formulation requirements, effectively improves the manufacturing level and application performance of energy storage fabrics, providing a better path for the development and market application of energy storage fabrics. Attached Figure Description

[0029] Figure 1 A schematic diagram of the structure of the printed energy storage battery fabric;

[0030] In the diagram: 1. Encapsulation material, 2. Positive electrode, 3. Negative electrode, 4. Gel electrolyte, 5. Energy storage battery fabric.

[0031] Figure 2 A schematic diagram showing how the apparent viscosity of the slurry used for printing electrodes changes with shear rate.

[0032] In the figure: the X-axis represents the shear velocity, in seconds (s). -1 The Y-axis represents the apparent viscosity, measured in Pa·s.

[0033] Figure 3 A schematic diagram showing how the modulus of the slurry used for printing electrodes changes with oscillation strain;

[0034] In the figure: Curve 1 shows the change in energy storage modulus; Curve 2 shows the change in loss modulus.

[0035] X-axis represents oscillatory strain, in units of %; Y-axis represents modulus, in units of Pa. Detailed Implementation

[0036] The present invention will be further described below with reference to the embodiments.

[0037] This method fabricates battery fabrics by printing electrode fabric, coating electrolyte, and combining this with polymer printing and encapsulation. Electrodes and electrolytes are stacked alternately, with the positive and negative electrodes encapsulated by a gel electrolyte and precisely assembled to form a fabric network. Photocurable polyurethane acrylate encapsulates the electrode fabric under mild conditions, demonstrating a novel approach to flexible energy storage fabric fabric fabrication. This method is simple and easy to implement, providing a new approach to solving the difficulties faced by flexible energy storage fabrics and is expected to further promote its practical application. Furthermore, this method is unprecedented in domestic and international literature or patent reports, highlighting its innovation.

[0038] The technical solution adopted in this invention, the method for 3D printing to prepare energy storage battery fabric, is as follows: the steps are performed sequentially, gradually printing to form the fabric as shown in the figure. Figure 1 The battery fabric structure shown:

[0039] Step 1: Printing of Electrode Fabric

[0040] (1) Use composite polymer, multi-walled carbon nanotubes and nanoelectrode active materials, mix them in a mass ratio of 1:1:2, add 5 to 10 times the mass of solid solvent, and dissolve and disperse them evenly by grinding or ball milling to obtain the slurry used for printing electrodes;

[0041] The active materials in the electrodes have a relatively stable discharge platform for the positive electrode (lithium iron phosphate particles, lithium permanganate particles) and for the negative electrode (lithium titanate particles, lithium titanium phosphate particles), and are resistant to water and ethanol. Carbon nanotubes are used as conductive agents in the electrodes. Their slender morphology under microscopic conditions has an excellent match with the fiber electrode configuration, which can build a rich conductive network in the fiber and play a certain role in supporting the electrode skeleton.

[0042] The composite polymer used in the electrode is a two-component polymer and photoinitiator I2959. Component A is a photocurable polymer, including polyethylene glycol diacrylate and polyethylene glycol dimethacrylate. These polymer components have good affinity and transport effects on lithium salts, thereby constructing good ion transport channels in the electrode. Component B is a high-viscosity polymer that can be rapidly physically cross-linked, including chitosan, sodium alginate, and polyvinylidene fluoride. These polymers can rapidly form cross-links with a certain strength under certain induction, thereby ensuring the molding and mechanical strength of the electrode. The mass of component A is 1 to 3 times the mass of component B. Within this ratio range, the two polymers can work together to balance good ion channels and mechanical properties.

[0043] The solvent used in the electrode paste varies depending on the type of polymer used. When the polymer is chitosan and sodium alginate, deionized water is used as the solvent. When the polymer is polyvinylidene fluoride, N-methylpyrrolidone is used as the solvent.

[0044] The paste used for printing electrodes needs to have specific rheological properties, specifically: a viscosity of 10. 2 ~10 4 Pa·s, and the viscosity decreases with increasing shear rate, such as Figure 2 As shown; furthermore, the storage modulus is higher than the loss modulus under low shear stress, but after being subjected to shear stress exceeding a certain level, the storage modulus becomes lower than the loss modulus, such as... Figure 3 As shown, good rheological properties can ensure the continuity and smoothness of electrode printing, and maintain structural stability after printing and extrusion, avoiding structural collapse and damage.

[0045] (2) After the slurry used for printing the electrode is ultrasonically degassed, it is placed in the syringe of an extrusion-type direct-write 3D printer and printed in a grid pattern. The grid line distance in the printed pattern is greater than or equal to 4 mm, and the extrusion speed during the printing process is 1~2 mm. 3 / s, the printing travel speed is 2~5 mm / s, the appropriate spacing and printing and extrusion ratio can ensure the structural integrity and reliability of the printed electrode fabric, and reserve space for printing electrolyte and encapsulation materials;

[0046] (3) After printing, copper and aluminum tabs are inserted into the unshaped electrodes, and then immersed in the coagulation bath for 10 minutes until the polymer component B in the electrodes is cross-linked and shaped, thus obtaining positive electrode fabric and negative electrode fabric respectively.

[0047] The coagulation bath used is a solution that enables component B in the composite polymer to undergo rapid physical cross-linking. For sodium alginate, it is a calcium chloride solution, where calcium ions can form cross-links between sodium alginate segments through electrostatic interactions. For chitosan, it is a sodium hydroxide solution, where alkaline sodium hydroxide can neutralize and dissolve the acid used in chitosan, causing chitosan to re-cross-link and precipitate. The electrode is solidified and shaped due to the cross-linking of the polymer.

[0048] Step 2: Printing and Coating of Gel Electrolytes

[0049] (1) The same components of the composite polymer in step one are used, but the mass of component A is adjusted to 3 to 4 times the mass of component B, so that the electrolyte part has better ionic conductivity. The solvent ratio is adjusted to 5 to 8 times the mass of the polymer, so that the gel electrolyte slurry has a certain fluidity, thereby encapsulating the electrode. Lithium sulfate is added to it until the concentration reaches 1 to 2 mol / L. After stirring until the polymer and lithium sulfate are dissolved, one-tenth of the polymer mass of vapor-deposited hydrophilic nano silica is added. After mixing evenly in a ball mill, a gel electrolyte precursor for printing is obtained.

[0050] (2) The gel electrolyte precursor is printed on both sides of the electrode fabric using a 3D printer with the same printing pattern and parameters as the electrode fabric, so that the printed gel electrolyte can cover and wrap the electrode fabric. During the printing process of the gel electrolyte, the ultraviolet light with a wavelength of 365 nm is continuously irradiated to crosslink the electrode fabric and component A in the gel electrolyte. The gel electrolyte is cured immediately after wrapping the electrode, leaving gaps between the mesh fabric.

[0051] (3) After printing, the pre-shaped gel electrolyte and the positive electrode fabric and negative electrode fabric wrapped by it are immersed together in a coagulation bath of 2 mol / L lithium sulfate for 10 min. Component B in the gel electrolyte cross-links to form a whole. Then, it is washed with 2 mol / L lithium sulfate solution to ensure that the polymer in the electrode and electrolyte is completely cross-linked, to wash away other unreacted substances, and to make the lithium salt fully penetrate evenly.

[0052] Step 3: Printing and encapsulating the energy storage fabric

[0053] (1) Mix photocurable polyurethane acrylate and 4% photoinitiator 1173, and add the same mass of polyethylene glycol acrylate monomer as solvent. After stirring and removing bubbles, transfer the mixture into the 3D printer syringe.

[0054] (2) Set the printing extrusion speed to 2~3 mm3 / s and the printing travel speed to 3~6 mm / s. Print on the front and back sides respectively, and irradiate with ultraviolet light during the printing process. Encapsulate the battery on the outer layer of the gel electrolyte to obtain the energy storage fabric.

[0055] Example 1

[0056] According to the steps described in the technical solution of this invention, lithium permanganate is selected as the positive electrode active material, lithium titanium phosphate is selected as the negative electrode active material, and component A of the composite polymer in the positive and negative electrodes and electrolyte is polyethylene glycol diacrylate, component B is chitosan, and photocurable polyurethane acrylate is used as the encapsulation material. The energy storage battery fabric is prepared step-by-step by printing according to the method of this invention. The specific capacity of the obtained energy storage battery fabric, calculated based on the mass of the positive electrode material, reaches 98 mAh·g. -1 It retains 89% of its initial capacity after 50 charge-discharge cycles.

[0057] Example 2

[0058] According to the steps described in the technical solution of this invention, lithium iron phosphate is used as the positive electrode active material, lithium titanate is selected as the negative electrode active material, polyethylene glycol diacrylate is used as component A in the composite polymer of the positive and negative electrodes and electrolyte, sodium alginate is used as component B, and photocurable polyurethane acrylate is used as the encapsulation material. The energy storage battery fabric is prepared step-by-step by printing according to the method of this invention. The specific capacity of the printed energy storage battery fabric reaches 152 mAh·g based on the mass of the positive electrode material. -1 It has good wearability characteristics, is breathable and flexible, and retains 91% of its initial capacity during charge and discharge cycles under 90° bending conditions.

[0059] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for 3D printing to prepare energy storage battery fabric, characterized in that... The steps of this method are as follows: Step 1: Printing of Electrode Fabric (1) Use composite polymer, multi-walled carbon nanotubes and nanoelectrode active materials, mix them in a mass ratio of 1:1:2, add 5 to 10 times the mass of solid solvent, and dissolve and disperse them evenly by grinding or ball milling to obtain the slurry used for printing electrodes; The composite polymer is composed of a two-component polymer and a photoinitiator I2959. The two-component polymer consists of component A and component B. Component A is a photocurable polymer, including polyethylene glycol diacrylate and polyethylene glycol dimethacrylate, and component B is a high-viscosity polymer that can be rapidly physically crosslinked, including chitosan, sodium alginate, or polyvinylidene fluoride. The mass of component A is 1 to 3 times the mass of component B. The active material is used for lithium iron phosphate particles and lithium permanganate particles as the positive electrode, and for lithium titanate particles or lithium titanium phosphate particles as the negative electrode. The solvent used is deionized water for chitosan and sodium alginate, and N-methylpyrrolidone for polyvinylidene fluoride; (2) After ultrasonically removing air bubbles, the slurry used for printing electrodes is placed in an extrusion-type direct-write 3D printer and printed in a grid pattern. The grid line distance in the printed pattern is greater than or equal to 4 mm, and the extrusion speed during the printing process is 1~2 mm. 3 / s, the printing travel speed is 2~5 mm / s; (3) After printing, copper and aluminum tabs are inserted into the unshaped electrodes, and then immersed in the coagulation bath for 10 min until the polymer component B in the electrodes is cross-linked and shaped, thus obtaining positive electrode fabric and negative electrode fabric respectively. Step 2: Printing and Coating of Gel Electrolytes (1) Use the same components and solvents of the composite polymer in step one, but adjust the mass of component A to 3 to 4 times the mass of component B, adjust the solvent ratio to 5 to 8 times the mass of the polymer, and add lithium sulfate to a concentration of 1 to 2 mol / L. After the polymer and lithium sulfate are dissolved, add one-tenth of the polymer mass of vapor-deposited hydrophilic nano silica, mix evenly in a ball mill, and obtain a gel electrolyte precursor for printing. (2) Place the gel electrolyte precursor in the syringe of the extrusion direct writing 3D printer, and print on both sides of the electrode fabric using the same printing pattern and parameters as the electrode fabric, so that the printed gel electrolyte can cover and wrap the electrode network. During the printing process of the gel electrolyte, keep the ultraviolet light with a wavelength of 365 nm continuously irradiated, so that the electrode fabric and component A in the gel electrolyte are crosslinked. (3) The pre-shaped gel electrolyte after printing and the positive electrode fabric and negative electrode fabric wrapped by it are immersed together in a coagulation bath of 2 mol / L lithium sulfate for 10 min. Component B in the gel electrolyte cross-links to form a whole, and then it is washed with 2 mol / L lithium sulfate solution. Step 3: Printing and encapsulating the energy storage fabric (1) Mix photocurable polyurethane acrylate and 4% photoinitiator 1173, and add the same mass of polyethylene glycol acrylate monomer as solvent. After stirring and removing bubbles, transfer the mixture into the 3D printer syringe. (2) Set the printing extrusion speed to 2~3 mm 3 The printing speed is 3~6 mm / s, and printing is performed on both sides. During the printing process, ultraviolet light is applied to encapsulate the battery on the outer layer of the gel electrolyte, thereby obtaining the energy storage fabric.

2. The method for 3D printing to prepare energy storage battery fabric according to claim 1, characterized in that: The viscosity of the paste used for printing electrodes is 10. 2 ~10 4 The viscosity is Pa·s, and decreases with increasing shear rate. Furthermore, the storage modulus is higher than the loss modulus under low shear stress, but becomes lower than the loss modulus after being subjected to a certain shear stress.

3. The method for 3D printing to prepare energy storage battery fabric according to claim 1, characterized in that: The coagulation bath used is a solution that enables component B in the composite polymer to undergo rapid physical cross-linking. For sodium alginate, it is a calcium chloride solution, and for chitosan, it is a sodium hydroxide solution.

4. The method for 3D printing to prepare energy storage battery fabric according to claim 1, characterized in that: After printing the gel electrolyte and the photocurable polymer, the rapid cross-linking and curing of the polymer encapsulates the material, preventing further flow and blockage of the pores in the mesh electrode fabric, thus preserving the fabric's breathability.

5. The method for 3D printing to prepare energy storage battery fabric according to claim 1, characterized in that: The prepared energy storage fabric has good flexibility due to the intrinsic flexibility of the electrodes, gel electrolyte, and encapsulating polymer, and can maintain stable charge and discharge performance during bending.

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