Structural energy storage integrated lithium ion battery, preparation method thereof and application of structural energy storage integrated lithium ion battery in cubesat

Abstract

The invention belongs to the technical field of structural batteries, and particularly discloses a structural energy storage integrated lithium ion battery, a preparation method thereof and application of the structural energy storage integrated lithium ion battery in a cubesat. The method comprises the following steps: coating the surface of a carbon fiber braided fabric with electrode slurry to respectively obtain a battery positive electrode and a battery negative electrode; and then placing the electrolyte, the diaphragm, the battery positive electrode and the battery negative electrode in the resin matrix, arranging the carbon fiber braided fabrics on two sides, and integrally curing with the resin matrix through a vacuum infusion or lamination curing molding process to obtain the structural energy storage integrated lithium ion battery. According to the structural energy storage integrated lithium ion battery prepared by the invention, the active material of the lithium ion battery can be directly integrated into the carbon fiber reinforced resin matrix to form a composite material with structural strength and an energy storage function; and the method is applied to the fields of miniature cubesat and other spacecrafts or unmanned aerial vehicles with high requirements on weight reduction and volume utilization rate.

Description

Technical Field

[0001] The present invention relates to the technical field of structural batteries, and in particular to a structural energy storage integrated lithium-ion battery, a preparation method thereof, and an application in a cube satellite. Background Art

[0002] With the rapid development of aerospace technology, CubeSats are attracting increasing attention due to their small size, light weight, short development cycle, and low cost. Traditionally, CubeSats require specialized battery modules (such as individually packaged lithium-ion battery packs), which not only consumes valuable internal space but also complicates assembly and maintenance. Therefore, integrating power systems that achieve high specific energy density and excellent mechanical performance within limited space has long been a key research topic in the CubeSat field.

[0003] Currently, carbon fiber reinforced composites have been widely used in the aerospace field. Their high specific strength and high specific modulus are conducive to reducing the weight of aircraft. However, the concept of integrating energy storage functions directly with structural parts, namely "structural batteries" or "structured energy storage composites", is still in the stage of continuous exploration and improvement in terms of achieving high-performance lithium-ion batteries while also maintaining structural mechanical properties. Although there have been studies on embedding ready-made lithium batteries into carbon fiber composites, problems such as material discontinuity, poor interface bonding, and increased overall weight often occur, and the value of the "structure + energy storage" multifunctional integration has not been fully realized.

[0004] Therefore, how to provide a structural energy storage integrated lithium-ion battery and its preparation method and application in cube satellites to directly replace the original skin or body structure of the spacecraft (especially cube satellites), thereby effectively saving internal space and reducing the total mass, and significantly improving the system-level specific energy utilization and structural efficiency is a difficult problem that needs to be solved urgently in this field. Summary of the Invention

[0005] In view of this, the present invention provides a structural energy storage integrated lithium-ion battery, a preparation method thereof, and an application in a cube satellite, in order to solve the problems of poor interface bonding and high overall weight of existing structural energy storage integrated composite materials, which cannot fully realize the value of the "structure + energy storage" multifunctional integration.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a structural energy storage integrated lithium-ion battery comprises the following steps:

[0008] 1) coating the electrode slurry on the surface of the carbon fiber braid to obtain the battery positive electrode and battery negative electrode respectively;

[0009] 2) Place the electrolyte, separator, battery positive electrode, and battery negative electrode in a resin matrix, and set carbon fiber woven fabrics on both sides. Through a vacuum infusion or lamination curing process, they are integrally cured with the resin matrix to obtain a structural energy storage integrated lithium-ion battery;

[0010] Among them, the resin matrix includes a resin material, a curing agent, and a modifier.

[0011] Preferably, the areal density of the carbon fiber woven fabric is 50 - 300 g / m 2 , the weaving method is plain weave, twill weave or warp knitting, the conductivity is 10 2 ~1.5×10 4 S / m, and the tensile strength ≥ 2 GPa.

[0012] Preferably, the electrode paste includes a positive electrode paste and a negative electrode paste;

[0013] The preparation method of the electrode paste is: mix the electrode active material, conductive agent, binder, and solvent to obtain the electrode paste;

[0014] When the electrode active material is a positive electrode material, a positive electrode paste is obtained; when the electrode active material is a negative electrode material, a negative electrode paste is obtained;

[0015] The mass ratio of the electrode active material, conductive agent, and binder is 20 - 80:5 - 90:5 - 10;

[0016] The positive electrode material includes one or more of LiFePO4, LiNi x Co y Mn z O2 and LiCoO2;

[0017] The negative electrode material includes one or more of graphite, graphene, and Si / C composites.

[0018] Preferably, in step 1), the coating amount of the positive electrode material in the battery positive electrode is 4 - 12 mg / cm 2 ;

[0019] The coating amount of the negative electrode material in the battery negative electrode is 3 - 9 mg / cm 2 .

[0020] Preferably, the electrolyte includes an ionic liquid electrolyte and / or a polymer gel electrolyte.

[0021] Preferably, the mass ratio of the resin material, curing agent, and modifier in the resin matrix is 100:20 - 35:0 - 15.

[0022] Preferably, the resin material includes one or more of epoxy resin, phenolic resin, bismaleimide, and polyimide resin;

[0023] The curing agent includes one or more of amine curing agents, anhydride curing agents, imidazole curing agents, and phenolic compounds;

[0024] The modifier includes a toughening agent and / or a coupling agent.

[0025] Preferably, the area ratio of the addition amount of the resin matrix to the carbon fiber woven fabric is 0.05 - 0.10 g / cm 2 .

[0026] Another object of the present invention is to provide a structural energy storage integrated lithium-ion battery prepared by the above preparation method.

[0027] Another object of the present invention is to provide an application of the structural energy storage integrated lithium-ion battery in a CubeSat. The structural energy storage integrated lithium-ion battery can be used as the outer shell or load-bearing surface of the CubeSat.

[0028] Through the above technical solutions, compared with the prior art, the present invention has the following beneficial effects:

[0029] System-level weight reduction and volume utilization improvement

[0030] Since the battery active layer and the carbon fiber load-bearing layer are co-cured into a single integral component, the metal shell, independent module bracket, and redundant cable connections are eliminated. The weight of the 1U-CubeSat is reduced by 25 - 30% compared with the traditional solution, and the available internal volume increases by ≥10%. At the same time, the panel energy density (calculated based on the mass of the entire composite board) can reach 35 - 45 Wh / kg, which is more than 30% higher than the existing "embedded" or "attached" batteries.

[0031] Structural / energy storage dual-performance coordination

[0032] By the method of the present invention, the tensile strength of the composite board is ≥210 MPa and the bending strength is ≥280 MPa, meeting the mechanical requirements of satellite skins and UAV hatch covers for load-bearing components. High-modulus Pitch-based carbon fibers can further increase the tensile strength to ≥300 MPa. At the same time, due to its high conductivity (≈1.5×10 4 Sm -1 ), the internal resistance of the electrode is reduced and the rate performance is significantly improved.

[0033] Interface integration and reliability improvement

[0034] The electrode paste is directly coated on the fiber fabric, and the resin to be cured penetrates into the active layer to form chemical bonds / physical interlocks; the "co-cured" interface has an interlaminar shear strength of the embedded battery layer increased by ≥40% compared with bolt or paste fixation, and there is no significant delamination after vibration (5 - 1000 Hz).

[0035] The gelled ionic liquid electrolyte fills the fabric micropores and is coated by the resin matrix, inhibiting the volatilization and leakage of the electrolyte. The capacity retention rate is >88% @ 200 cycles after thermal vacuum ( cycling).

[0036] Safety and environmental adaptability

[0037] The ionic liquid system has the characteristics of intrinsic flame retardancy and low vapor pressure; the resin-fiber network provides three-dimensional encapsulation, and the risk of thermal runaway is significantly reduced compared with the liquid carbonate system.

[0038] The composite board remains structurally intact in thermal vacuum, ultraviolet irradiation and micro-impact experiments, meeting the design requirements for a 3-year service life of low-earth orbit satellites.

[0039] Modular design possible, easy to series and parallel connect

[0040] Principle breakthrough

[0041] Through the idea of "co-curing - co-loading", for the first time, highly conductive carbon fibers are used as both the stress-bearing skeleton and the current collector, and the resin matrix is used to simultaneously achieve the triple functions of mechanical connection, ion isolation and heat conduction, fundamentally solving the bottlenecks of traditional split systems such as "poor interface bonding, complex assembly, and weight duplication", and giving full play to the multi-functional coupling benefits of materials. Specific implementation method

[0042] The present invention provides a preparation method of a structural energy storage integrated lithium-ion battery, including the following steps:

[0043] 1) Coat the electrode paste on the surface of the carbon fiber fabric to obtain the battery positive electrode and the battery negative electrode respectively;<>

[0044] 2) Place the electrolyte, separator, battery positive electrode and battery negative electrode in the resin matrix, set carbon fiber fabrics on both sides, and integrally cure with the resin matrix through a vacuum infusion or lamination curing molding process to obtain a structural energy storage integrated lithium-ion battery.

[0045] In the present invention, the resin matrix includes a resin material, a curing agent and a modifier.

[0046] In the present invention, the areal density of the carbon fiber fabric is 50 - 300 g / m 2 , specifically it can be 60 g / m 2 , 80 g / m 2 , 100 g / m2 、150 g / m 2 、200 g / m 2 、250 g / m 2 ; The weaving method is plain weave, twill weave or warp knitting, and the conductivity is 10 2 ~1.5×10 4 S / m, specifically it can be 10 3 S / m, 10 4 S / m, 1.2×10 4 S / m; The tensile strength ≥ 2 GPa, specifically it can be 2.5 GPa, 3 GPa, 3.5 GPa, 4 GPa.

[0047] In the present invention, the carbon fiber woven fabric includes PAN-based carbon fiber and / or pitch-based carbon fiber, and the carbon fiber woven fabric further includes a pretreatment step.

[0048] In the present invention, the pretreatment includes removing sizing agent treatment or surface modification treatment.

[0049] In the present invention, the electrode paste includes a positive electrode paste and a negative electrode paste; the preparation method of the electrode paste is: mixing electrode active material, conductive agent, binder and solvent to obtain the electrode paste.

[0050] In the present invention, when the electrode active material is a positive electrode material, the positive electrode paste is obtained; when the electrode active material is a negative electrode material, the negative electrode paste is obtained.

[0051] In the present invention, the mass ratio of the electrode active material, conductive agent and binder is 20~80:5~90:5~10, preferably 40~60:20~80:6~9, and further preferably 50:50~60:5~8.

[0052] In the present invention, the positive electrode material includes one or more of LiFePO4, LiNi x Co y Mn z O2 and LiCoO2; the negative electrode material includes one or more of graphite, graphene and Si / C composite; the conductive agent includes one or more of conductive carbon black, carbon nanotubes and graphene; the binder includes one or more of polyvinylidene fluoride (PVDF), aqueous styrene-butadiene rubber / carboxymethyl cellulose (SBR / CMC) combination and polyacrylic acid (PAA).

[0053] In the present invention, the coating amount of the positive electrode material in the battery positive electrode in step 1) is 4~12 mg / cm 2 , specifically it can be 5 mg / cm 2 、6 mg / cm 2 、7 mg / cm2 、 8 mg / cm 2 、 9 mg / cm 2 、 10 mg / cm 2 、 11 mg / cm 2 。

[0054] In the present invention, the coating amount of the negative electrode material in the battery negative electrode is 3-9 mg / cm 2 , specifically it can be 4 mg / cm 2 、 5 mg / cm 2 、 6 mg / cm 2 、 7 mg / cm 2 、 8 mg / cm 2 。

[0055] In the present invention, the electrolyte includes an ionic liquid electrolyte and / or a polymer gel electrolyte.

[0056] In the present invention, the mass ratio of the resin material, curing agent and modifier in the resin matrix is 100:20-35:0-15, the addition amount of the modifier is not 0, preferably 100:25-30:5-10, and more preferably 100:25:5.

[0057] In the present invention, the resin material includes one or more of epoxy resin, phenolic resin, bismaleimide and polyimide resin; the curing agent includes one or more of amine curing agents, acid anhydride curing agents, imidazole curing agents and phenolic compounds; the modifier includes a toughening agent and / or a coupling agent.

[0058] In the present invention, the area ratio of the addition amount of the resin matrix to the carbon fiber woven fabric is 0.05-0.10 g / cm 2 , specifically it can be 0.06 g / cm 2 、 0.07 g / cm 2 、 0.08 g / cm 2 、 0.09 g / cm 2 。

[0059] In the present invention, the areas of the carbon fiber woven fabrics in the battery positive electrode and the battery negative electrode are equal.

[0060] In the present invention, before the vacuum infusion or lamination curing molding process, the positional relationship in the numerical substrate is carbon fiber woven fabric|battery positive electrode|separator (loaded with electrolyte)|battery negative electrode|carbon fiber woven fabric.

[0061] The present invention also provides a structural energy storage integrated lithium-ion battery prepared by the described preparation method.

[0062] The present invention also provides an application of the integrated structural energy storage lithium-ion battery in a CubeSat, and the integrated structural energy storage lithium-ion battery can be used as the outer shell or the load-bearing surface of the CubeSat.

[0063] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention (all steps in the embodiments and experiments of the present invention that are sensitive to water are operated in a dry glove box with moisture < 20 ppm).

[0064] Example 1

[0065] Select a T700 grade PAN-based carbon fiber fabric with a areal density of 200 g / m 2 , the weaving method is plain weave, and the warp and weft density is 6 ends / cm -1 ×6 picks / cm -1 , after being treated with a chemical desizing agent (degreased with acetone at 50 °C for 30 min, sized with 5 g / L NaOH at 70 °C for 20 min → neutralized with HCl → rinsed with deionized water → dried at 120 °C), the conductivity is 8×10 -1 S / m, and the tensile strength is 4.5 GPa. 2

[0066] Mix LiFePO4 (from MTI Corporation, particle size < 1 μm), Super P conductive carbon black, and PVDF binder in a mass ratio of 65:20:15, and dissolve them in N-methylpyrrolidone to obtain a positive electrode slurry. Coat the positive electrode slurry on both surfaces of the above carbon fiber fabric and dry it at 80 °C for 12 hours to obtain a battery positive electrode, and the coating amount of the positive electrode material is 6 mg / cm -2 .

[0067] Mix graphite powder (from Sigma-Aldrich, particle size < 20 μm), Super P conductive carbon black, and PVDF binder in a mass ratio of 80:10:10, and dissolve them in N-methylpyrrolidone to obtain a negative electrode slurry. Coat the negative electrode slurry on both surfaces of the above carbon fiber fabric and dry it at 80 °C for 12 hours to obtain a battery negative electrode, and the coating amount of the negative electrode material is 5 mg / cm -2 .

[0068] Mix Epon 828 epoxy resin (from Hexion, epoxy equivalent EEW ≈ 185 g / eq), curing agent MHHPA (methylhexahydrophthalic anhydride), and CTBN (carboxy-terminated butadiene acrylonitrile rubber) liquid toughening agent in a mass ratio of 100:25:5 to obtain a resin matrix.

[0069] Dissolve 287 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in 1000 mL of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4), and stir magnetically at 60 °C for 4 h to obtain a 1 mol / L ionic liquid electrolyte (the molar mass of LiTFSI is 287 g / mol).

[0070] Assembly of the structural energy storage integrated lithium-ion battery:

[0071] Place a Whatman glass fiber separator between the positive electrode and the negative electrode of the battery, and drop the electrolyte on the separator; then assemble the above electrode assembly together with the blank carbon fiber layers on both sides (uncoated carbon fiber surface layer (200 g / m 2 , plain weave) / positive electrode of the battery / pre-impregnated with 0.5 mg / cm 2 Whatman glass fiber separator of ionic liquid / negative electrode of the battery / uncoated carbon fiber surface layer) for resin matrix vacuum infusion (the resin matrix vacuum infusion amount is 4.2 g); under the condition of a vacuum of 10 3 Pa, impregnate for 4 h, then cure at 80 °C for 10 h, and then keep warm at the curing temperature of 120 °C for 2 h. Finally, a carbon fiber reinforced structural battery composite plate (structural energy storage integrated lithium-ion battery) with a size of 8 cm × 8 cm is obtained.

[0072] Performance testing:

[0073] Mechanical property testing conditions: Tensile strength: GB / T 3357-2014 (equivalent to ASTM D3039); Bending strength: GB / T 1449-2005 (equivalent to ASTM D7264) three-point bending method. The test results show that its tensile strength reaches 210 MPa and the bending strength is 280 MPa;

[0074] Electrochemical property testing conditions:

[0075] Take out the cured battery composite plate with a size of 8 cm × 8 cm, and directly use the uncoated carbon fiber surface layers on both sides as the positive and negative current collectors. Gently clamp the exposed carbon fiber layers at both ends of the composite plate with metal clamps. A layer of ultra-thin conductive copper foil or conductive silver paste can be laid on the clamping surface first to ensure that the contact resistance < 0.1 Ω.

[0076] Testing environment:

[0077] Room temperature (25 ± 1 °C); The testing system uses LAND CT2001A.

[0078] Charge and discharge parameters:

[0079] Constant current charge and discharge at 0.2C (34 mA), voltage range 2.5V - 4.2V, without constant voltage stage; cycle 50 times, record the initial discharge specific capacity and cycle retention rate.

[0080] Test results: Initial specific capacity 30 mAh·g -1 (calculated based on the total mass of the composite plate), energy density 35 Wh·kg -1 , capacity retention rate 92% after 50 cycles.

[0081] This example shows that the battery with this structure can exhibit good energy storage performance at low rates, while maintaining a high tensile strength, which verifies the feasibility of using it as a material for both load-bearing and energy storage. It can accurately reflect the design concept that the "structural battery" itself is both a load-bearing component and a positive and negative current collector, eliminating the need to attach traditional metal foils.

[0082] Example 2

[0083] The difference between this example and Example 1 is that SuperP conductive carbon black and multi-walled carbon nanotubes with a ratio of 15:5 are used instead of the SuperP conductive carbon black in Comparative Document 1; the coating amount of the positive electrode material is adjusted to 8 mg / cm -2 .

[0084] Performance test:

[0085] Mechanical properties: After modification with carbon nanotubes, the interfacial bonding between the overall resin matrix and the electrode layer is enhanced, with a tensile strength of 220 MPa and a flexural strength of 290 MPa;

[0086] Electrochemical properties: At a rate of 0.5C, the panel specific capacity reaches 32 mAh / g, the energy density can reach 36 Wh / kg, and the capacity retention rate is 90% after 100 cycles. Compared with Example 1, the conductivity is better and the rate performance is improved.

[0087] Example 3

[0088] The difference between this embodiment and Embodiment 1 lies only in the preparation method of the electrolyte: 1.0 g of poly(vinylidene fluoride - hexafluoropropylene) (P(VDF - HFP)) was dissolved in 1.0 g of pre - weighed 1 - ethyl - 3 - methylimidazolium tetrafluoroborate (EMIMBF4), and magnetically stirred at 60 °C for 1 h to obtain an initial viscous solution; subsequently, the remaining 3.0 g of EMIMBF4 was added step - by - step and stirred until the solution returned to a uniformly flowing state; then 1.07 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was added dropwise to this system to make the LiTFSI concentration reach 1.2 mol / L, and stirring was continued at 60 °C for 1 h to obtain a homogeneous semi - gel electrolyte. The electrolyte prepared in this embodiment is in a semi - gel state, which can improve the static encapsulation effect and enhance the overall mechanical compatibility. Based on the state of the electrolyte, the method of dropping the electrolyte in Embodiment 1 was adjusted to scraping coating.

[0089] Performance test:

[0090] Since the gel electrolyte has a certain self - supporting force and better interfacial bonding, the peel strength of the panel is increased by 10%.

[0091] Electrochemical performance: The discharge specific capacity can reach 30 mAh / g at 0.5 C, and the cycle stability is still excellent. The capacity retention rate is 88% after 200 cycles.

[0092] This embodiment shows that by introducing a polymer - based gel into the ionic liquid, the interfacial stability and safety can be further improved, which is suitable for spacecraft application scenarios that require higher cycle life and reduced risk of electrolyte flow.

[0093] Embodiment 4

[0094] Pitch - based high - modulus carbon fiber (Toray M55J) with a surface density of 120 g / m 2 , and the weaving method is plain weave. After chemical pretreatment + vacuum heat annealing (vacuum annealing at 350 °C for 2 h in a nitrogen atmosphere), the conductivity is 1.5×10 4 S / m, and the tensile strength is 3300 MPa (corresponding tensile modulus of 540 GPa).

[0095] Mix LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), Super P conductive carbon black, and PVDF binder in a mass ratio of 70:15:15, and dissolve them in N - methylpyrrolidone to obtain a positive electrode slurry. The positive electrode slurry is coated on both surfaces of the above - mentioned carbon fiber fabric and dried at 80 °C for 12 hours to obtain a battery positive electrode, and the coating amount of the positive electrode material is 8 mg / cm 2 .

[0096] Graphite powder (Sigma-Aldrich, particle size <20 μm), Super P conductive carbon black, and SBR+CMC binder (ZEON BM-451B: Sunrose HT-2000 = 5:1) were mixed at a mass ratio of 80:10:10, dissolved in N-methylpyrrolidone to obtain the negative electrode slurry. The negative electrode slurry was coated on both surfaces of the above carbon fiber fabric and dried at 80 °C for 12 hours to obtain the battery negative electrode, and the coating amount of the negative electrode material was 7 mg / cm 2 .

[0097] The modified bismaleimide resin (Araldite BMI T012, Huntsman), curing agent (4,4'-diaminodiphenyl ether DDS), and silane coupling agent (KH-560) were mixed at a mass ratio of 100:25:5 to obtain the resin matrix.

[0098] 1 mol / L LiPF6 was dissolved in an improved ionic liquid mixed system of EC:DEC = 1:1 (volume ratio) (containing 30% EMIMBF4) to balance the combination of conventional carbonate solvents and ionic liquids.

[0099] The carbonate mixed solvent of EC:DEC = 1:1 (mL / mL) (3.5 mL EC + 3.5 mL DEC) was mixed with 30 wt% EMIM-BF4 ionic liquid (3.0 mL), and stirred at 60 °C for 1 h; then 1 mol / L LiPF6 (containing 1.27 g LiPF6 in 10 mL of the above solvent system) was added, and stirring was continued for 2 h to obtain a translucent flowing electrolyte.

[0100] Assembly of the structural energy storage integrated lithium-ion battery:

[0101] A Celgard 2325 PP / PE / PP three-layer microporous membrane (thickness 25 μm, Celgard) was placed between the battery positive electrode and the battery negative electrode, and the electrolyte was dropped on the membrane (0.6 mg / cm of the electrolyte was scrape-coated on the membrane, and left standing for 2 min and then the surface free liquid was gently sucked); then the above electrode assembly and the blank carbon fiber layers on both sides were subjected to vacuum perfusion of the resin matrix (the addition amount of the resin matrix was 2.5 g); under the condition of a vacuum of 10 2 Pa, after impregnation for 4 hours, cured at 120 °C for 4 hours, and then cured at 180 °C for 2 hours. Finally, a carbon fiber reinforced structural battery composite board (structural energy storage integrated lithium-ion battery) with a size of 8 cm × 8 cm was obtained. 3 Pa conditions for 4 hours, cured at 120 °C for 4 hours, and then cured at 180 °C for 2 hours. Finally, a carbon fiber reinforced structural battery composite board (structural energy storage integrated lithium-ion battery) with a size of 8 cm × 8 cm was obtained.

[0102] Performance test:

[0103] Mechanical strength: Tensile strength is increased to 300 MPa, flexural strength is above 350 MPa, and modulus > 100 GPa;

[0104] Electrochemistry: Benefiting from the high specific capacity of NCM811 and the good electrical conductivity of Pitch-based carbon fiber, the energy density of the whole plate can reach 40 - 45 Wh / kg at a rate of 0.5C. After 300 cycles, the capacity retention rate is 82%, featuring long-life characteristics.

[0105] This example demonstrates that by selecting Pitch-based carbon fibers with higher modulus and higher electrical conductivity, and using the high specific capacity cathode NCM811, the comprehensive mechanical and electrochemical properties of the structural composite plate can be further improved.

[0106] Example 5

[0107] Assembly and Application in 1U CubeSat

[0108] 1. Panel assembly:

[0109] Select 4 pieces of 8 cm × 8 cm panels prepared in Example 2, and connect them in series through metal connecting pieces, with the total voltage reaching 12 - 14V.

[0110] Assemble the 4 panels onto the skeleton of a 1U-sized (10 cm × 10 cm × 10 cm) CubeSat, replacing the original satellite outer shell panel.

[0111] 2. Testing:

[0112] Under a 1A load, it can continuously discharge for about 30 minutes, during which there is no obvious deformation or stress concentration on the panel shell;

[0113] 10% additional space can be vacated inside the whole satellite for scientific payloads or other equipment;

[0114] After the mechanical vibration test (5 - 1000 Hz), there are no visible cracks or delaminations on the panel surface, and the battery discharge performance has no significant attenuation.

[0115] Under the thermal vacuum test environment (-30°C to 50°C cycle), the panel functions remain stable.

[0116] This example clearly demonstrates the practical process and effects of applying the structural battery composite panel of the present invention to CubeSats. Compared with the design of traditional independent battery modules, the present invention reduces the system weight by 25 - 30% under the same power supply capacity and leaves more internal space for payload use.

[0117] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0118] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of a structural energy storage integrated lithium-ion battery, characterized in that, It includes the following steps: 1) Coating electrode slurries on the surface of carbon fiber woven fabrics to obtain the positive electrode and negative electrode of the battery respectively; 2) Placing the electrolyte, separator, positive electrode and negative electrode of the battery in a resin matrix, with carbon fiber woven fabrics arranged on both sides, and integrally curing with the resin matrix through a vacuum infusion or lamination curing molding process to obtain a structural energy storage integrated lithium-ion battery; Among them, the resin matrix includes a resin material, a curing agent and a modifier.

2. The preparation method of an integrated structural energy storage lithium-ion battery according to claim 1, wherein, The areal density of the carbon fiber fabric is 50 to 300 g / m 2 , the weaving method is plain weave, twill weave or warp knitting, and the conductivity is 10 2 ~1.5×10 4 S / m, and the tensile strength is ≥2 GPa.

3. The preparation method of an integrated structure energy storage lithium ion battery according to claim 2, characterized in that, The electrode slurries include a positive electrode slurry and a negative electrode slurry; The preparation method of the electrode slurry is: mixing an electrode active material, a conductive agent, a binder and a solvent to obtain the electrode slurry; When the electrode active material is a positive electrode material, a positive electrode slurry is obtained; when the electrode active material is a negative electrode material, a negative electrode slurry is obtained; The mass ratio of the electrode active material, the conductive agent and the binder is 20-80:5-90:5-10; The positive electrode material includes one or more of LiFePO4, LiNi x Co y Mn z O2, and LiCoO2; The negative electrode material includes one or more of graphite, graphene and Si / C composites.

4. The preparation method of an integrated structural energy storage lithium-ion battery according to claim 3, characterized in that, The coating amount of the positive electrode material in the positive electrode of the battery described in step 1) is 4 to 12 mg / cm 2 ; The coating amount of the negative electrode material in the battery negative electrode is 3-9 mg / cm 2 .

5. The preparation method of an integrated structure energy storage lithium ion battery according to any one of claims 1 to 4, characterized in that, The electrolyte includes an ionic liquid electrolyte and / or a polymer gel electrolyte.

6. The preparation method of an integrated structural energy storage lithium-ion battery according to claim 5, characterized in that, The mass ratio of the resin material, the curing agent and the modifier in the resin matrix is 100:20-35:0-15.

7. The preparation method of an integrated structural energy storage lithium-ion battery according to claim 6, wherein The resin material includes one or more of epoxy resin, phenolic resin, bismaleimide and polyimide resin; The curing agent includes one or more of amine curing agents, anhydride curing agents, imidazole curing agents and phenolic compounds; The modifier includes a toughening agent and / or a coupling agent.

8. The preparation method of an integrated structural energy storage lithium-ion battery according to claim 7, characterized in that, The area ratio of the addition amount of the resin matrix to the carbon fiber woven fabric is 0.05 to 0.10 g / cm 2 .

9. A structural energy storage integrated lithium-ion battery prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the integrated lithium-ion battery with structural energy storage described in claim 9 in a cube satellite, characterized in that, The structural energy storage integrated lithium-ion battery can be used as the outer shell or load-bearing surface of a cube satellite.