Current collector, electrode plate, battery, battery pack and electric equipment

Abstract

The invention provides a current collector, an electrode plate, a battery, a battery pack and electric equipment. The current collector comprises a porous polymer matrix and a reinforcing material existing in the porous polymer matrix. According to the current collector provided by the invention, the reinforcing material and the porous structure of the porous polymer matrix exist in the porous polymer matrix, so that the rapid transmission of ions is facilitated, the ion transmission resistance is reduced, and the rate capability of the battery is improved. The reinforcing material is dispersed in the porous polymer matrix, so that the mechanical strength of the current collector can be improved, deformation and degradation of the battery in charge and discharge cycles are reduced, and the cycle performance of the battery is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a current collector, an electrode sheet, a battery, a battery pack and an electrical device. Background Art

[0002] In the development of battery technology, current collectors, as key components of battery electrodes, play a vital role. Traditional current collector materials are mainly aluminum foil and copper foil, which are widely used due to their excellent conductivity.

[0003] However, the main function of traditional current collectors is to provide an electron conduction path, and they have poor ion transport performance and mechanical strength, which affects the rate performance and cycle performance of the battery. Summary of the Invention

[0004] The main purpose of the present invention is to provide a current collector with excellent ion transport performance and high mechanical strength, which can improve the rate performance and cycle performance of the battery.

[0005] The present invention also provides a method for preparing a current collector, which can prepare the above-mentioned current collector, has a simple process and low cost.

[0006] The present invention also provides an electrode sheet comprising the above-mentioned current collector. Therefore, when the electrode sheet is applied to a battery, the rate performance and cycle performance of the battery can be improved.

[0007] The present invention also provides a battery comprising the electrode sheet, so that the battery has higher rate performance and cycle performance.

[0008] The present invention also provides a battery pack comprising at least two of the above batteries, so that the battery pack has higher rate performance and cycle performance.

[0009] The present invention also provides an electrical device comprising the above-mentioned battery or the above-mentioned battery pack. Therefore, the performance of the battery related to the electrical device is relatively excellent.

[0010] In a first aspect, the present invention provides a current collector comprising a porous polymer matrix and a reinforcing material present in the porous polymer matrix.

[0011] In the current collector as described above, the reinforcing material includes carbon material and / or ceramic material.

[0012] In the current collector as described above, the reinforcing material includes fibrous material and / or granular material.

[0013] In the current collector as described above, the reinforcing material includes carbon nanofibers and / or nano-ceramic particles.

[0014] In the current collector as described above, the reinforcing material accounts for 0.1%-10% of the total mass of the porous polymer matrix and the reinforcing material.

[0015] In the current collector as described above, the porous polymer matrix contains imine bonds.

[0016] As described above, the monomer raw materials for forming the porous polymer matrix include aldehyde monomers and amino monomers; the aldehyde monomers include at least one of the structures shown in Formula 1-1 to Formula 1-3:

[0017]

[0018] wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4;

[0019]

[0020] wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4;

[0021]

[0022] wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4;

[0023] And / or, the amino monomer includes at least one of the structures shown in Formula 2-1 to Formula 2-5:

[0024]

[0025] The current collector as described above has a porosity of 30%-70%.

[0026] The current collector as described above further comprises: a metal layer present on at least one side of the porous polymer matrix;

[0027] Preferably, the metal layer is present on both sides of the porous polymer matrix.

[0028] As for the current collector described above, the single metal layer has an average pore size of 5 μm to 20 μm in a region with a thickness of 3 μm to 8 μm from the outside to the inside.

[0029] As described above, the current collector, the metal layer includes a porous metal foil, and the porous metal foil includes one or more of Li, Al, Na, K, Mg, Ca, Sr, Ba, Ga, In, Ge, Sn, and transition metals.

[0030] The current collector as described above, wherein the thickness of the current collector is 21 μm-31 μm;

[0031] And / or, the tensile strength of the current collector is greater than or equal to 280 MPa.

[0032] In a second aspect, the present invention provides a method for preparing the current collector as described above, comprising the following steps:

[0033] A raw material system including monomer raw materials and reinforcing materials for forming the porous polymer matrix is ​​polymerized to obtain the current collector.

[0034] The method for preparing the current collector as described above further comprises: providing a metal layer on at least one surface of the current collector;

[0035] Preferably, a metal layer is provided on both side surfaces of the current collector.

[0036] In the above-mentioned method for preparing the current collector, the mass percentage of the reinforcing material in the raw material system is 0.15%-15%.

[0037] In a third aspect, the present invention provides an electrode sheet comprising the current collector as described above or a current collector prepared according to the method for preparing the current collector as described above.

[0038] In the electrode sheet as described above, one side of the current collector is the positive electrode active material layer, and the other side is the negative electrode active material layer.

[0039] In a fourth aspect, the present invention provides a battery comprising the electrode sheet as described above.

[0040] In a fifth aspect, the present invention provides a battery pack comprising at least two batteries as described above.

[0041] In a sixth aspect, the present invention provides an electrical device comprising the battery or the battery pack as described above.

[0042] The current collector provided by the present invention incorporates a reinforcing material within a porous polymer matrix. The porous structure of the porous polymer matrix facilitates rapid ion transport, reduces ion transport resistance, and thus improves the battery's rate performance. The reinforcing material dispersed within the porous polymer matrix enhances the mechanical strength of the current collector, reducing deformation and degradation during charge and discharge cycles, thereby improving the battery's cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present invention or related technologies. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0044] Figure 1 A schematic structural diagram of a current collector provided by the present invention;

[0045] Figure 2 This is a schematic structural diagram of an electrode sheet provided by the present invention. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0047] With the increasing global demand for renewable energy, energy storage batteries, particularly lithium-ion and sodium-ion batteries, are becoming an attractive alternative to traditional energy storage solutions due to their high energy density and excellent cycle performance. However, the energy degradation faced by these batteries during high-rate charge and discharge remains a challenge that needs to be addressed. As a key component of battery electrodes, the structural design and performance optimization of the current collector are particularly important for improving the overall battery performance.

[0048] The inventors of this application have discovered that although traditional current collector materials, such as aluminum foil and copper foil, have good electronic conductivity, their dense metal foil structure exposes some key defects in battery applications. First, traditional metal foil lacks a porous structure, which makes it difficult for the electrolyte to effectively penetrate into the interior of the electrode material. This structure limits the transmission path of lithium ions and sodium ions, so that the ions can only diffuse unidirectionally through the electrode material body. Under high-rate (such as ≥3C) charge and discharge conditions, this restricted transmission mode will lead to significant concentration polarization, resulting in a sharp decline in battery capacity. In addition, the electrode material will undergo volume changes during the charge and discharge process, especially materials such as silicon negative electrodes, whose volume expansion rate can be as high as 300%. This volume change will produce local stress concentration at the solid-solid contact interface, leading to delamination and detachment between the current collector and the active material. According to statistics, more than 70% of battery capacity decay can be attributed to mechanical failure at the interface. That is, the traditional current collector can only serve as an electron transport medium and cannot simultaneously meet the multifunctional requirements such as ion path optimization and stress buffering.

[0049] By adding reinforcing materials to the polymer matrix, the ion transport performance and mechanical strength of the current collector can be improved, thereby improving the rate performance and cycle performance of the battery.

[0050] Based on this, in the first aspect, the present invention provides a current collector, such as Figure 1As shown, it includes a porous polymer matrix and a reinforcing material present in the porous polymer matrix.

[0051] The reinforcing material in the present invention can provide certain mechanical properties, generally has higher strength and stiffness, and can improve the overall mechanical properties of the composite material. For example, it can include at least one of carbon materials, ceramic materials, metal materials, and silicon materials.

[0052] The current collector provided by the present invention has reinforcing materials in the porous polymer matrix, which can improve the ion transmission performance and mechanical strength of the current collector, thereby improving the rate performance and cycle performance of the battery. The reason for this is that the porous structure of the porous polymer matrix provides a large number of channels, which is conducive to the rapid transmission of ions and significantly reduces the ion transmission resistance, thereby improving the rate performance of the battery. In addition, the porous structure can better adsorb and retain the electrolyte, increase the contact area between the electrolyte and the electrode material, and further enhance the ion transmission efficiency. The reinforcing materials are dispersed in the porous polymer matrix, which can significantly improve the overall mechanical strength and thermal stability of the current collector, which is conducive to maintaining the stability of the battery structure, reducing the deformation and degradation of the battery during the charge and discharge cycle, thereby improving the cycle performance of the battery.

[0053] In the present invention, the porous polymer matrix may be a cross-linked structure.

[0054] Thus, the current collector provided by the present invention comprises a reinforcing material within a porous polymer matrix. The porous structure of the porous polymer matrix facilitates rapid ion transport, reduces ion transport resistance, and thus improves the battery's rate performance. The reinforcing material dispersed within the porous polymer matrix enhances the mechanical strength and thermal stability of the current collector, reducing deformation and degradation during charge and discharge cycles, thereby improving the battery's cycle performance.

[0055] In some embodiments of the present invention, the reinforcing material includes carbon material and / or ceramic material, which can further improve the mechanical strength and stability of the current collector, prevent it from deformation or degradation during use, improve the stability of the battery in repeated charge and discharge cycles, and improve the cycle life of the battery.

[0056] In some embodiments of the present invention, the reinforcement material comprises a fibrous material and / or a granular material.

[0057] Fiber materials have high tensile strength and toughness, which can significantly enhance the mechanical properties of current collectors, helping to improve their crack resistance and wear resistance. Granular materials can be filled into porous polymer matrices to provide additional structural support, thereby improving the overall strength and rigidity of the current collector. Furthermore, fiber and granular materials can optimize the pore structure and provide more efficient ion transport channels, which can help improve the battery's rate performance.

[0058] Specifically, the reinforcing material includes carbon nanofibers and / or nano-ceramic particles, which can further improve the ion transport performance and mechanical strength of the current collector, thereby improving the rate performance and cycle performance of the battery.

[0059] In some embodiments of the present invention, the percentage of the reinforcing material to the total mass of the porous polymer matrix and the reinforcing material is 0.1%-10%, for example, it can be 0.1%, 1%, 5%, 7%, 9%, 10% or any two thereof.

[0060] In the present invention, the percentage of the reinforcing material in the total mass of the porous polymer matrix and the reinforcing material within the above range can effectively improve the mechanical strength and stability of the current collector, optimize the ion and electron transport pathways of the electrode, and thus improve the rate capability and cycle performance of the battery. It can also reduce the aggregation of the reinforcing material in the porous polymer matrix.

[0061] In some embodiments of the present invention, the porous polymer matrix contains imine bonds.

[0062] The porous polymer matrix of the present invention contains imine bonds, which possess high strength and toughness, enabling the porous polymer matrix to withstand higher mechanical stresses and improving the structural stability of the current collector. Furthermore, the imine bonds possess high thermal stability, maintaining their structural integrity at higher temperatures, thereby enhancing the safety and stability of the battery in high-temperature environments. Furthermore, the imine bonds enhance the overall stability of the porous polymer matrix, making it more resistant to harsh chemical environments such as battery electrolytes, thereby extending the battery's service life.

[0063] In addition, the porous polymer matrix of the present application constructs a dynamic cross-linking network through hydrogen bonds (formed by hydrogen atoms covalently linked to electronegative atoms, such as O and N, and another electronegative site, such as O, F, Cl, Br or activated CH). A large number of intermolecular hydrogen bonds connect the porous polymer matrix like a "zipper", giving the material excellent mechanical strength and toughness. At the same time, due to the dynamic reversibility of hydrogen bonds (which can be broken by heat or solvent action and can be reorganized after conditions are restored), it has recyclability that is difficult for traditional polymers to achieve both. Compared with traditional materials such as polyimide (PI) that rely on permanent covalent cross-linking to obtain high performance but are difficult to recycle, the porous polymer matrix of the present application achieves a balance between mechanical strength and multiple recycling capabilities through reversible hydrogen bonds, providing a new approach for the sustainable development of high-performance materials.

[0064] In some embodiments of the present invention, the monomer raw materials for forming the porous polymer matrix include aldehyde monomers and amino monomers; the aldehyde monomers include at least one of the structures shown in Formulas 1-1 to 1-3:

[0065]

[0066] wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4;

[0067]

[0068] wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4;

[0069]

[0070] wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4;

[0071] In some embodiments, the amino monomer includes at least one of the structures shown in Formula 2-1 to Formula 2-5:

[0072]

[0073] In the present invention, the reaction ratio of aldehyde monomers and amino monomers is efficient and has strong reversibility, which can effectively form the structure of porous polymer. Amino monomers can provide multiple reaction sites, form a cross-linked structure with aldehyde monomers, and improve the mechanical strength and thermal stability of polymer. In addition, amino monomers can enhance the interfacial compatibility of polymer matrix and reinforcing material through hydrogen bonds and other weak interactions.

[0074] In the present invention, the molar ratio of the aldehyde monomer to the amino monomer may be 1:(0.5-2), and the concentration of the aldehyde monomer in the raw material system may be 0.1 mol / L-0.2 mol / L.

[0075] In some embodiments of the present invention, the porosity of the current collector is 30%-70%, for example, it can be 30%, 40%, 50%, 60%, 70% or any two thereof.

[0076] In the present invention, the porosity of the current collector within the above range provides sufficient space for electrolyte penetration and ion migration, which helps improve ion transport efficiency, thereby enhancing the battery's rate performance and overall energy efficiency. At the same time, it maintains the mechanical strength and structural integrity of the porous polymer matrix, preventing deformation or damage to the current collector during charge and discharge cycles.

[0077] In the present invention, the porous polymer matrix is ​​usually present in a layered form.

[0078] In some embodiments of the present invention, the current collector further comprises: a metal layer present on at least one side of the porous polymer matrix; preferably, the metal layer exists on both sides of the porous polymer matrix.

[0079] In the present invention, the presence of the metal layer provides an excellent electron conduction path, significantly reducing the resistance of the current collector, thereby improving the battery's energy efficiency and rate performance. Furthermore, the metal layer increases the mechanical strength and rigidity of the current collector, providing additional structural support and preventing deformation or damage during the battery's charge and discharge cycles.

[0080] In some embodiments of the present invention, the metal layer has an average pore size of 5 μm to 20 μm in a region with a thickness of 3 μm to 8 μm from the outside to the inside.

[0081] For example, the thickness may be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or a range consisting of any two thereof; the pore size may be 5 μm, 10 μm, 12 μm, 15 μm, 20 μm or a range consisting of any two thereof.

[0082] In the present invention, the metal layer has a thickness of 3μm-8μm from the outside to the inside, and a pore size of 5μm-20μm, that is, the surface layer of the metal layer is kept at a submicron pore size, allowing the electrolyte to quickly penetrate into the porous polymer matrix, thereby improving the ion transmission efficiency and rate performance of the battery.

[0083] In some specific embodiments of the present invention, the metal layer includes a porous metal foil, and the porous metal foil includes one or more of Li, Al, Na, K, Mg, Ca, Sr, Ba, Ga, In, Ge, Sn, and transition metals.

[0084] In the present invention, the metal layer includes a porous metal foil. The type of the porous metal foil is within the above range. These metals have good electrical conductivity, can significantly reduce the resistance of the current collector, and improve the energy efficiency and rate performance of the battery.

[0085] In some embodiments of the present invention, the thickness of the current collector is 21 μm to 31 μm, for example, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, or any two thereof. This thickness range provides sufficient material to ensure good conductivity while maintaining a lightweight design. This helps provide a stable electron and ion transport path without significantly increasing the weight of the battery.

[0086] In some embodiments, the tensile strength of the current collector is greater than or equal to 280 MPa, for example, 280 MPa, 290 MPa, 300 MPa, 320 MPa, 340 MPa, 360 MPa, or a range consisting of any two thereof.

[0087] In the present invention, the tensile strength of the current collector ensures that the current collector can withstand mechanical stress without breaking or deforming during manufacturing, assembly and operation, which is crucial to the long-term reliability and durability of the battery.

[0088] In a second aspect, the present invention provides a method for preparing the current collector as described above, comprising the following steps:

[0089] A raw material system including a monomer raw material for forming a porous polymer matrix and a reinforcing material is polymerized to obtain a current collector.

[0090] In the present invention, the raw material system is subjected to a polymerization reaction. During the polymerization process, the monomer raw materials used to form the porous polymer matrix are converted into the porous polymer matrix, and the reinforcing material is uniformly dispersed in the porous polymer matrix, which is beneficial to improving the mechanical strength and ion transport performance of the current collector, and can improve the rate performance and cycle performance of the battery.

[0091] Specifically, the following steps may be included:

[0092] 1) Mixing monomer raw materials for forming a porous polymer matrix and a reinforcing material in a solvent to form a precursor solution.

[0093] 2) Add a small amount of acidic solvent to the precursor solution and stir to obtain a mixed solution.

[0094] 3) The mixed solution formed above is subjected to a film forming process to obtain a current collector.

[0095] Wherein, the solvent may be methyl pyrrolidone solution.

[0096] The acidic solvent, such as acetic acid, is added as a catalyst to promote the reaction of monomer raw materials for forming the porous polymer matrix, thereby forming the porous polymer matrix.

[0097] In some embodiments of the present invention, the method further comprises: disposing a metal layer on at least one surface of the current collector; preferably, disposing a metal layer on both surfaces of the current collector.

[0098] In this invention, a metal layer is placed on the surface of the current collector. This metal layer provides an excellent electron conduction path, significantly reducing the current collector's resistance and improving the battery's energy efficiency and rate performance. Furthermore, the metal layer increases the mechanical strength and rigidity of the current collector, providing additional structural support and preventing deformation or damage during the battery's charge and discharge cycles.

[0099] In some embodiments of the present invention, the mass percentage of the reinforcing material in the raw material system is 0.15%-15%, for example, it can be 0.15%, 1.5%, 7.5%, 10.5%, 13.5%, 15% or any two thereof.

[0100] In the present invention, the mass percentage of the reinforcing material in the raw material system is within the above range, which can effectively improve the mechanical strength and stability of the current collector, improve the conductivity and ion transport properties of the polymer matrix, and thus improve the rate performance and cycle performance of the battery.

[0101] In a third aspect, the present invention provides an electrode sheet comprising the current collector as described above or a current collector prepared according to the current collector preparation method as described above. Therefore, the electrode sheet is applied to a battery to improve the rate performance and cycle performance of the battery.

[0102] In some embodiments of the present invention, Figure 2 As shown, one side of the current collector contains the positive electrode active material layer, and the other side contains the negative electrode active material layer. This reduces material usage and the overall battery volume, improving material utilization and the battery's energy density. It also shortens the electron and ion transmission paths, lowering the battery's internal resistance, thereby improving the battery's rate performance and energy efficiency. This also helps balance the mechanical stress of the electrodes, reducing deformation and damage caused by volume changes during charge and discharge, and extending the battery's cycle life.

[0103] In a fourth aspect, the present invention provides a battery comprising the electrode sheet as described above. The battery has advantages corresponding to those of the electrode sheet, which will not be described in detail.

[0104] The battery of the present invention includes, in addition to the electrode sheet, an electrolyte, wherein the electrolyte can be any electrolyte conventionally used in the art.

[0105] It should be noted that the current collector of the present invention can be applied to solid-state batteries. By optimizing the porosity and electrolyte wettability of the porous polymer matrix, it can adapt to the solid electrolyte interface and improve ion transmission efficiency. The current collector of the present invention can also be applied to sodium-ion batteries and zinc-ion batteries. The porosity of the metal layer can be adjusted to adapt to the transmission requirements of different ionic radii.

[0106] In a fifth aspect, the present invention provides a battery pack comprising at least two batteries as described above. The battery pack has advantages corresponding to those of the electrode sheet described above, which will not be described in detail.

[0107] In a sixth aspect, the present invention provides an electrical device comprising the battery as described above. The electrical device has advantages corresponding to those of the electrode sheet described above, which will not be described in detail.

[0108] The electrical equipment of the present invention can be conventional electrical equipment in the field, such as power equipment (such as electric vehicles), electronic equipment (such as computers, mobile phones, digital cameras, printers, fax machines, etc.), wearable devices (such as watches, bracelets, VR glasses, etc.), household appliances (such as air conditioners, refrigerators, washing machines, microwave ovens, etc.), etc., without special restrictions.

[0109] The technical solution of the present invention is further described below with reference to specific embodiments.

[0110] Example 1

[0111] The method for preparing the battery of this embodiment includes the following steps:

[0112] 1) Dialdehyde-bis(ethylpropyl)-perylenetetracarboxylic acid diimide, 4,4-diaminodiphenyl ether (structure shown in Formula 2-1), and carbon nanofibers are added to a methyl pyrrolidone solution to form a precursor solution. The molar ratio of dialdehyde-bis(ethylpropyl)-perylenetetracarboxylic acid diimide to 4,4-diaminodiphenyl ether is 1:1, the concentration of dialdehyde-bis(ethylpropyl)-perylenetetracarboxylic acid diimide in the precursor solution is 0.1 mol / L, and the mass percentage of carbon nanofibers in the raw material system of dialdehyde-bis(ethylpropyl)-perylenetetracarboxylic acid diimide, 4,4-diaminodiphenyl ether, and carbon nanofibers is 0.15%.

[0113] 2) Add 0.1M acetic acid to the precursor solution obtained in step 1), stir at 60°C, and cast the solution onto a metal substrate. Using a doctor blade, control the thickness of the separator to 15μm. Then, imidize the composite material in a box furnace and form a thin film using a step-by-step ramp procedure. The imidization temperature program is as follows: (a) increase the temperature from 25°C to 100°C at a rate of 5°C / min; (b) hold at 100°C for 30 minutes; (c) increase the temperature to 200°C at a rate of 5°C / min; (d) hold at 200°C for 30 minutes; (e) increase the temperature to 300°C at a rate of 5°C / min; (f) hold at 300°C for 30 minutes; (g) cool to room temperature in the furnace and dry to obtain the current collector precursor.

[0114] 3) coating both sides of the current collector precursor obtained in step 2) with Al metal to obtain a current collector. The current collector comprises a porous polymer matrix and carbon nanofibers as a reinforcement material present in the porous polymer matrix, wherein the reinforcement material accounts for 0.1% by weight of the current collector, the porous polymer matrix contains imine bonds, and Al metal layers are present on both sides of the porous polymer matrix. The average pore size of the single Al metal layer from the outer to the inner 6 μm thickness region is 20 μm. The porosity of the current collector is 42%, the thickness of the current collector is 21 μm, and the tensile strength of the current collector is 282 MPa.

[0115] 4) Sodium ferric pyrophosphate (NFPP) powder: conductive carbon nanotubes: PVDF are mixed in a mass ratio of 100:2.5:2.5, with a solid content of 56%, to form a positive electrode slurry; hard carbon: conductive carbon nanotubes: SBR: CMC are mixed in a mass ratio of 100:2:2:2.5, with a solid content of 48%, to form a negative electrode slurry. After ensuring that the viscosity and fineness of the slurry are qualified, they are coated on the front and back sides of the above-mentioned current collector respectively. After coating, they are rolled, slit, die-cut, laminated, hot-pressed, assembled, dried, and then injected with electrolyte (1.0M NaPF6 / EC:PC:DEC=1:1:1 (volume ratio) + 2wt% VC). After chemical composition, a sodium ion soft-pack battery is obtained.

[0116] Example 2

[0117] The preparation method of the battery of Example 2 is basically the same as that of Example 1, except that the mass percentage of carbon nanofiber in the raw material system is 1.5%.

[0118] Example 3

[0119] The preparation method of the battery of Example 3 is basically the same as that of Example 1, except that the carbon nanofiber accounts for 7.5% by weight of the raw material system.

[0120] Example 4

[0121] The preparation method of the battery of Example 4 is basically the same as that of Example 1, except that the carbon nanofiber accounts for 15% by weight of the raw material system.

[0122] Example 5

[0123] The preparation methods of the battery of Example 5 are basically the same as those of Example 1, except that the average pore size of the 6 μm thick region from the outside to the inside of the single-layer Al metal layer is 5 μm.

[0124] Example 6

[0125] The preparation methods of the batteries of Example 6 and Example 1 are basically the same, except that in step 2), the thickness of the separator is controlled to be 25 μm and the thickness of the current collector is controlled to be 31 μm by a scraper.

[0126] Example 7

[0127] The preparation method of the battery of Example 7 is basically the same as that of Example 6, except that the mass percentage of carbon nanofiber in the raw material system is 1.5%.

[0128] Example 8

[0129] The preparation method of the battery of Example 8 is basically the same as that of Example 6, except that the carbon nanofiber accounts for 7.5% by weight of the raw material system.

[0130] Example 9

[0131] The preparation method of the battery of Example 9 is basically the same as that of Example 6, except that the carbon nanofiber accounts for 15% by weight of the raw material system.

[0132] Example 10

[0133] The preparation methods of the batteries of Example 10 and Example 6 are basically the same, except that the average pore size of the 6 μm thick region from the outside to the inside of the single-layer Al metal layer is 5 μm.

[0134] Example 11

[0135] The preparation method of the battery of Example 11 is basically the same as that of Example 1, except that the carbon nanofibers in step 1) are replaced with nano-ceramic particles of aluminum oxide.

[0136] Comparative Example 1

[0137] The preparation methods of the batteries of Comparative Example 1 and Example 1 are basically the same, except that no reinforcing material carbon nanofiber is added to the raw material system.

[0138] Comparative Example 2

[0139] The preparation methods of the batteries of Comparative Example 2 and Example 6 are basically the same, except that no reinforcing material carbon nanofiber is added to the raw material system.

[0140] Comparative Example 3

[0141] The preparation method of the battery of Comparative Example 3 is basically the same as that of Example 1, except that the current collector is a 15 μm polyimide film purchased from the supplier Xingyuan Materials.

[0142] Test example:

[0143] 1. The percentage of reinforcing material in the total mass of porous polymer matrix and reinforcing material:

[0144] 1) Accurately weigh a certain amount of current collector sample (such as 10mg-50mg). 2) If the metal layer of the current collector is copper foil, soak the current collector in sulfuric acid or nitric acid. If the metal layer of the current collector is aluminum foil, soak the current collector in sodium hydroxide. 4) Filter, wash, and obtain insoluble porous polymer and reinforcing material, and dry them to constant weight (recorded as m0). 5) Then dissolve the porous polymer and reinforcing material in 3M H2SO4+5% H2O2 and stir. 6) Filter, wash, and obtain insoluble reinforcing material residue, and dry it to constant weight. 6) Accurately weigh the mass of the reinforcing material residue (recorded as m1). 7) Calculate the mass percentage of the reinforcing material: mass percentage of reinforcing material = m1 / m0×100%.

[0145] 2. Metal layer aperture test:

[0146] 1) Take the current collector and randomly select 5-10 holes in the metal layer using a scanning electron microscope (SEM). Count the diameter of each hole. 2) Use software (such as ImageJ) to assist in the measurement and statistics to obtain the average pore diameter.

[0147] 3. Current collector thickness test:

[0148] 1) Equipment Selection: Precision micrometer, micrometer screw (0.001mm graduation). 2) Zero Calibration: Calibrate the equipment to zero before measurement. 3) Sampling: Cut a current collector test piece, ensuring that the surface is free of wrinkles. 4) Multi-Point Measurement: Take multiple measurements at different locations (e.g., 5-10 points) and take the average value to determine the current collector thickness.

[0149] 4. Mechanical strength test:

[0150] Equipment: Universal material testing machine (equipped with high-precision force sensor and displacement sensor), manual clamps (to ensure that the sample is firmly clamped and does not slip), sample cutting molds (to ensure that the sample size is consistent).

[0151] Sample Preparation: Size: Cut the current collector sample according to the standard (such as ASTM D882). The recommended size is 100mm × 10mm (length × width). Quantity: Prepare at least 5 samples for each test.

[0152] Pretreatment: Place under constant temperature and humidity conditions (such as 25°C, 50% RH) for 24 hours to eliminate the impact of the environment on performance.

[0153] Test conditions: Temperature: 25°C, Humidity: 50% RH, Tensile rate: 10 mm / min.

[0154] Test steps: 1) Secure the current collector in the fixture, ensuring the clamping area is flat and wrinkle-free. 2) Set the testing machine parameters (e.g., stretch rate, initial gauge length). 3) Start the test and record the load-displacement curve until the current collector breaks. 4) Record the tensile strength at the time of fracture. 5) Repeat the test for at least five samples and take the average value.

[0155] 5. Porosity test:

[0156] Test equipment: gas permeameter (equipped with pressure sensor and flow meter), sample clamp (ensure good sealing), gas source (nitrogen).

[0157] Sample Preparation Size: Cut the current collector sample according to the equipment requirements, usually a circular sample with a diameter of 25mm. Quantity: Test at least 3 samples per group and take the average value.

[0158] Pretreatment: Place under constant temperature and humidity conditions (25°C, 50% RH) for 24 hours.

[0159] Test conditions: Gas: Nitrogen. Pressure: 0.1 bar - 0.5 bar. Temperature: 25°C.

[0160] Test steps: Secure the current collector sample in a fixture, ensuring a good seal. Introduce gas and adjust to the set pressure. Record the gas flow rate (Q) and time (t) through the current collector sample. Porosity = Q / t. Repeat the test for at least three samples and calculate the average value.

[0161] 6. Rate performance test: Place the battery in a constant temperature box at 25℃ for 2 hours, then charge it to 3.8V at a constant current and constant voltage of 0.25C, and cut off at 0.05C. Record the corresponding charge capacity Q 充 Then charge at 0.1C constant current and constant voltage to 3.8V, and cut off at 0.025C. Leave for 5 minutes, and discharge at different rates (1C, 2C, 5C, 10C, 20C) to 2.0V, and record the discharge capacity Q. 放 , and the charge Q 充 Comparison can get the discharge rate under different rates, discharge rate = Q 放 / Q 充 .

[0162] 7. Cycle performance: At 25°C, charge the battery to 3.8V at a constant current of 1C, then charge it to 3.8V at a constant voltage of 0.5C, and then discharge it to 2.0V at a discharge rate of 1C. Repeat this charge and discharge cycle 300 times. Measure the discharge capacity Q1 at the first cycle and the discharge capacity Q at the 300th cycle. 300 The capacity retention rate after 300 cycles is Q = Q 300 / Q1×100%.

[0163] Table 1

[0164]

[0165]

[0166] As shown in Table 1, the current collector provided by the present invention comprises a reinforcing material within a porous polymer matrix. The porous structure of the porous polymer matrix facilitates rapid ion transport, reduces ion transport resistance, and thus improves the battery's rate performance. The reinforcing material dispersed within the porous polymer matrix enhances the mechanical strength and thermal stability of the current collector, reducing deformation and degradation during charge and discharge cycles, thereby improving the battery's cycle performance.

[0167] From the comparison of Examples 1-4 and Examples 6-9, it can be seen that as the mass percentage of the reinforcing material in the porous polymer matrix increases, the discharge rate and cycle performance of the battery gradually improve.

[0168] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A current collector, characterized in that: The invention comprises a porous polymer matrix and a reinforcing material existing in the porous polymer matrix.

2. The current collector according to claim 1, characterized in that The reinforcing material includes carbon material and / or nano-ceramic material.

3. The current collector according to claim 1 or 2, characterized in that: The reinforcement material includes fibrous material and / or granular material.

4. The current collector according to any one of claims 1 to 3, characterized in that: The reinforcing material includes carbon nanofibers and / or nano-ceramic particles.

5. The current collector according to any one of claims 1 to 4, characterized in that: The percentage of the reinforcing material to the total mass of the porous polymer matrix and the reinforcing material is 0.1%-10%.

6. The current collector according to any one of claims 1 to 5, characterized in that: The porous polymer matrix contains imine bonds.

7. The current collector according to any one of claims 1 to 6, characterized in that: The monomer raw materials for forming the porous polymer matrix include aldehyde monomers and amino monomers; the aldehyde monomers include at least one of the structures shown in Formula 1-1 to Formula 1-3: wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4; wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4; wherein X is selected from at least one of H, F, Cl, and Br, and n is selected from any integer from 1 to 4; And / or, the amino monomer includes at least one of the structures shown in Formula 2-1 to Formula 2-5:

8. The current collector according to any one of claims 1 to 7, characterized in that: The porosity of the current collector is 30%-70%.

9. The current collector according to any one of claims 1 to 8, characterized in that: Also includes: a metal layer present on at least one side of the porous polymer matrix; Preferably, the metal layer is present on both sides of the porous polymer matrix.

10. The current collector according to claim 9, characterized in that The metal layer has a thickness of 3 μm to 8 μm from the outside to the inside, and an average pore size of 5 μm to 20 μm.

11. The current collector according to claim 9 or 10, characterized in that: The metal layer includes a porous metal foil, and the porous metal foil includes one or more of Li, Al, Na, K, Mg, Ca, Sr, Ba, Ga, In, Ge, Sn, and transition metals.

12. The current collector according to any one of claims 1 to 11, characterized in that: The thickness of the current collector is 21 μm-31 μm; And / or, the tensile strength of the current collector is greater than or equal to 280 MPa.

13. A method for preparing the current collector according to any one of claims 1 to 12, characterized in that: The following steps are involved: A raw material system including monomer raw materials and reinforcing materials for forming the porous polymer matrix is ​​polymerized to obtain the current collector.

14. The method for preparing a current collector according to claim 13, wherein: Also includes: Disposing a metal layer on at least one side surface of the current collector; Preferably, a metal layer is provided on both side surfaces of the current collector.

15. The method for preparing a current collector according to claim 13 or 14, characterized in that: The mass percentage of the reinforcing material in the raw material system is 0.15%-15%.

16. An electrode sheet, characterized in that: The present invention relates to a current collector according to any one of claims 1 to 12 or a current collector prepared according to the method for preparing the current collector according to any one of claims 13 to 15.

17. The electrode sheet according to claim 16, characterized in that: One side of the current collector is a positive electrode active material layer, and the other side is a negative electrode active material layer.

18. A battery, characterized in that: The electrode sheet according to claim 16 or 17 is included.

19. A battery pack, characterized in that: Comprising at least two batteries according to claim 18.

20. An electrical device, characterized in that: Comprising the battery according to claim 18 or the battery pack according to claim 19.

Images