Method and apparatus for producing a nickel-iron alloy foil

Abstract

The application provides a preparation method and device of a nickel-iron alloy foil. The preparation method of the nickel-iron alloy foil comprises the following steps: providing an insoluble anode, an electroplating solution and a cathode, performing electroplating treatment to form a nickel-iron alloy film layer on the surface of the cathode; the main salt of the electroplating solution comprises divalent nickel salt and divalent iron salt; during the electroplating treatment, the electroplating solution is sequentially circulated for electroplating, reduction treatment and filtration treatment, and the concentration of trivalent iron ions in the electroplating solution is less than or equal to 1 g / L; and the nickel-iron alloy film layer is separated from the surface of the cathode to prepare a nickel-iron alloy foil. The preparation method can prepare a nickel-iron alloy foil with more uniform thickness, good strength and good bending resistance, and can continuously and efficiently prepare a long roll.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method and apparatus for preparing nickel-iron alloy foil. Background Technology

[0002] In recent years, the application range of batteries such as lithium-ion batteries has become increasingly wide, and they are now widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in many fields such as power tools, electric bicycles, electric motorcycles, and electric vehicles. Due to the significant advancements in battery technology, higher requirements have been placed on their energy density, cycle performance, and safety performance.

[0003] Nickel-iron alloy foil, with its superior strength, is increasingly attracting attention as a negative electrode current collector due to its ability to effectively resist the expansion of high-energy-density negative electrode materials and reduce the likelihood of electrode cracking caused by expansion. Traditionally, nickel-iron alloy foil is prepared by electroplating using a soluble anode. However, this method results in uneven thickness and plating contamination, leading to a decrease in the foil's strength and bending resistance. Summary of the Invention

[0004] Based on this, this application provides a method for preparing a nickel-iron alloy foil with good strength and bending resistance, as well as an apparatus for preparing the nickel-iron alloy foil.

[0005] The first aspect of this application provides a method for preparing a nickel-iron alloy foil, comprising the following steps:

[0006] An insoluble anode, an electroplating solution, and a cathode are provided for electroplating treatment, forming a nickel-iron alloy film on the surface of the cathode;

[0007] The main salts of the electroplating solution include divalent nickel salt and divalent iron salt; during the electroplating process, the electroplating solution is circulated sequentially for electroplating, reduction treatment and filtration treatment, and the concentration of trivalent iron ions in the electroplating solution is ≤1g / L;

[0008] The nickel-iron alloy film is separated from the surface of the cathode to prepare a nickel-iron alloy foil.

[0009] This application attempts to utilize an insoluble anode in the preparation of nickel-iron alloy foil. During electroplating, the electroplating solution is circulated and reduced, ensuring that the concentration of ferric ions in the solution is ≤1 g / L. Combined with filtration, this reduces the amount of reducing agent returning to the electroplating process as impurities, thus minimizing its impact on the coating quality. Therefore, by using an insoluble anode, the prepared nickel-iron alloy foil exhibits good strength, bending resistance, and uniform thickness. Furthermore, by replacing traditional soluble anodes with insoluble anodes, the problems associated with soluble anodes are reduced, resulting in good thickness consistency of the nickel-iron alloy foil in both the conveying and perpendicular directions. No anode sludge is generated, reducing contamination of the plating solution and coating. It is not limited by anode dissolution, allowing for continuous production of long rolls (≥5000 m) without frequent anode plate replacements, resulting in high production efficiency.

[0010] In some embodiments, the reducing agent used in the reduction process includes an inorganic reducing agent; optionally, the inorganic reducing agent includes one or more of sulfides and sulfurous compounds.

[0011] Further optionally, the sulfide includes one or more of hydrogen sulfide, ammonium sulfide, ferrous sulfide, ferric disulfide, nickel sulfide, and sodium sulfide;

[0012] Further optionally, the sulfurous compound includes one or more of sulfurous acid, ammonium sulfite, sodium sulfite, and potassium sulfite.

[0013] In some embodiments, the mass ratio of the inorganic reducing agent to the electroplating solution is 1:(100~100000). By using a reasonable amount of inorganic reducing agent, a good reduction effect can be achieved while avoiding the introduction of excessive additives, which would affect subsequent filtration and separation, and reduce the amount of additives entering the electroplating step.

[0014] In some embodiments, the filtration process uses a filter medium comprising a fibrous material, optionally including one or more of polyester fiber, glass fiber, and flax fiber. By employing a suitable filter medium, unreacted reducing agents or post-reaction precipitates can be effectively filtered and removed, reducing their adverse effects on the electroplating coating and resulting in a coating with better strength and bending resistance.

[0015] In some embodiments, the reduction treatment temperature is 0°C to 100°C; and / or the reduction treatment time is 0.1 min to 60 min.

[0016] In some embodiments, the reducing agent used in the reduction treatment includes an organic reducing agent; optionally, the organic reducing agent includes one or more of glucose, ascorbic acid, phenol, catechol, hydroquinone, and citric acid.

[0017] In some embodiments, the mass ratio of the organic reducing agent to the electroplating solution is 1:(100~100000). By using a reasonable amount of organic reducing agent, a good reduction effect can be achieved while avoiding the introduction of excessive additives, which would affect subsequent filtration and separation, and reduce the amount of additives entering the electroplating step.

[0018] In some embodiments, the filtration process uses activated carbon as the filter medium. Using a suitable filter medium can effectively remove both reacted and unreacted organic matter, reducing its adverse effects on the plating layer and resulting in a plating layer with better strength and bending resistance.

[0019] In some embodiments, the reduction treatment temperature is 0°C to 100°C; and / or the reduction treatment time is 0.1 min to 30 min.

[0020] In some embodiments, the filtration process is followed by an additive replenishment step between electroplating and the filtration process. The added additives include one or more of the following: primary brighteners, secondary brighteners, wetting agents, and complexing agents. After the electroplating solution is filtered by activated carbon, some of the electroplating additives are adsorbed and lost. This additive replenishment step can be added to maintain a balance of additive content in the electroplating solution.

[0021] A second aspect of this application provides an apparatus for preparing nickel-iron alloy foil, comprising an electroplating apparatus, a reduction apparatus, and a filter connected in sequence by pipelines, wherein the reduction apparatus includes a reducing agent;

[0022] Optionally, an additive replenishment device is also provided between the filter and the electroplating device. Attached Figure Description

[0023] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0024] Figure 1 This is a schematic diagram of the apparatus for preparing nickel-iron alloy foil according to one embodiment of this application.

[0025] Figure 2 This is a schematic diagram of an apparatus for preparing nickel-iron alloy foil according to another embodiment of this application.

[0026] Figure 3This is a schematic diagram of a secondary battery according to one embodiment of this application.

[0027] Figure 4 for Figure 3 An exploded view of a secondary battery according to one embodiment of this application is shown.

[0028] Figure 5 This is a schematic diagram of an electrical device that uses a secondary battery as a power source according to one embodiment of this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Secondary battery; 11. Housing; 12. Electrode assembly; 13. Cover plate; 2. Electrical device. Detailed Implementation

[0031] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be independently included or excluded, and they can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0034] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0035] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0037] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0038] In this application, unless otherwise specified, A (e.g., B) means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0039] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0040] In this application, "insoluble anode" refers to an anode that does not dissolve itself when an electric current passes through it, but only undergoes an oxidation reaction.

[0041] During battery cycling, some batteries experience electrode cracking, leading to battery failure, especially wound battery systems with high expansion forces, such as high-energy-density battery systems using silicon anode materials and thin current collectors. Furthermore, some stacked systems with high expansion forces also exhibit electrode edge cracking. In some embodiments, electrode cracking during battery cycling can be mitigated by increasing the current collector strength, for example, by replacing traditional copper foil with nickel-iron alloy foil.

[0042] In some embodiments, nickel-iron alloy foil can be prepared by electroplating using a soluble anode. The principle is as follows: the anode plate is composed of nickel, iron, and graphite plates arranged in a certain area ratio; the cathode is typically a titanium roller. During electroplating, divalent nickel and divalent iron ions in the electrolyte deposit on the surface of the titanium roller to form a nickel-iron alloy coating. Simultaneously, nickel and iron from the anode dissolve into divalent nickel and divalent iron ions, which replenish the cations consumed in the plating solution. After electroplating, the nickel-iron alloy coating is peeled off from the cathode to obtain the nickel-iron alloy foil. If the concentration of trivalent iron ions in the plating solution is high, their corresponding oxides or hydroxides will be incorporated into the coating, increasing its brittleness. Using a soluble anode in the preparation of nickel-iron alloy foil can reduce the formation of trivalent iron ions.

[0043] However, research has shown that nickel-iron alloy foils prepared using soluble anodes suffer from uneven foil thickness and coating contamination, leading to a decrease in foil strength and bending resistance. Furthermore, the anode plates dissolve and require frequent replacement, making continuous and efficient foil preparation difficult and resulting in low production efficiency.

[0044] One embodiment of this application provides a method for preparing nickel-iron alloy foil, comprising the following steps:

[0045] Electroplating is performed in the presence of an insoluble anode, an electroplating solution, and a cathode to form a nickel-iron alloy film on the surface of the cathode.

[0046] The main salts of the electroplating solution include divalent nickel salt and divalent iron salt; during the electroplating process, the electroplating solution is circulated sequentially for electroplating, reduction treatment and filtration treatment, and the concentration of trivalent iron ions in the electroplating solution is ≤1g / L;

[0047] The nickel-iron alloy film is separated from the surface of the cathode to prepare a nickel-iron alloy foil.

[0048] This application attempts to employ an insoluble anode in the preparation of nickel-iron alloy foil. During electroplating, the electroplating solution is circulated and reduced, ensuring that the concentration of ferric ions in the solution is ≤1 g / L. Combined with filtration, this reduces the amount of reducing agent returning to the electroplating process as impurities, thus minimizing its impact on the coating quality. Therefore, by utilizing an insoluble anode, nickel-iron alloy foil with good strength, bending resistance, and uniform thickness can be prepared.

[0049] In other examples of this application, since insoluble anodes can be used instead of traditional soluble anodes, the problems associated with soluble anodes can be reduced, resulting in good thickness consistency of nickel-iron alloy foil in both the conveying direction and the direction perpendicular to the conveying direction; no anode sludge is generated, reducing the contamination of the plating solution and coating by anode sludge; it is not limited by anode dissolution, and long rolls of, for example, ≥5000m can be continuously produced without the need for frequent replacement of anode plates, resulting in high production efficiency.

[0050] Without restriction, an oxidation reaction occurs on the anode surface, with ionic reaction formulas as shown in (1) and (2). Oxygen is released from the anode, and simultaneously, ferrous iron in the plating solution is oxidized to ferric iron. A reduction reaction occurs on the cathode roller surface, with ionic reaction formulas as shown in (3), (4), (5), and (6). While a nickel-iron alloy plating layer is deposited on the cathode roller surface, a small amount of hydrogen is produced. Examples of reactions involved in the electroplating process are shown below:

[0051] Reaction at the insoluble anode:

[0052] (1);

[0053] (2);

[0054] The reaction on the cathode titanium roller:

[0055] (3);

[0056] (4);

[0057] (5);

[0058] (6).

[0059] As the electroplating time progresses, the ferrous ions in the plating solution are oxidized to ferric ions. The inclusion of ferric ions in the plating layer increases the brittleness of the plating layer and reduces its overall performance. This application uses a circulating method to perform reduction and filtration treatment on the plating solution during electroplating, which can fully reduce the ferric ions in the electroplating solution to ferrous ions, without introducing additional impurities.

[0060] Without limitation, the reducing agent used in the reduction treatment includes one or more of organic and inorganic reducing agents.

[0061] In some embodiments, the reducing agent used in the reduction process includes an inorganic reducing agent. Further, the inorganic reducing agent includes one or more of sulfides and sulfite compounds.

[0062] As an example, the chemical reaction formula for the reaction of sulfides with ferric ions is as follows (7):

[0063] (7)

[0064] As an example, the chemical reaction formula for the reaction of sulfite compounds with ferric ions is as follows (8):

[0065] (8)

[0066] Formulas (7) and (8) can be used to counteract the ferric ions generated by the anodic reaction (1).

[0067] Without limitation, the sulfide includes one or more of hydrogen sulfide, ammonium sulfide, ferrous sulfide, ferric disulfide, nickel sulfide, and sodium sulfide; the sulfurous compound includes one or more of sulfurous acid, ammonium sulfite, sodium sulfite, and potassium sulfite.

[0068] In some embodiments, during the electroplating process, the concentration of ferric ions in the electroplating solution is ≤0.5g / L, further ≤0.3g / L, and even further ≤0.2g / L.

[0069] In some embodiments, the mass ratio of the inorganic reducing agent to the electroplating solution is 1:(100~100000). Specifically, the mass ratio of the inorganic reducing agent to the electroplating solution includes, but is not limited to: 1:100, 1:500, 1:1000, 1:2000, 1:5000, 1:10000, 1:50000, and 1:100000. Using a reasonable amount of inorganic reducing agent can achieve a good reduction effect while avoiding the introduction of excessive additives, which could affect subsequent filtration and separation, and reduce the amount of additives entering the electroplating step.

[0070] In some embodiments, the filter medium used in the filtration process includes fibrous materials. By employing a suitable filter medium, unreacted reducing agents or post-reaction precipitates can be effectively filtered and removed, reducing their adverse effects on the electroplating coating and resulting in a coating with better strength and bending resistance. Further, the fibrous material includes one or more of polyester fibers, glass fibers, and flax fibers.

[0071] In some embodiments, the reduction treatment temperature is 0°C to 100°C. Specifically, the reduction treatment temperature includes, but is not limited to: 0°C, 10°C, 20°C, 50°C, 80°C, 100°C, or any range between the two.

[0072] Furthermore, the reduction treatment time can be adjusted according to the activity of the reducing agent. In some embodiments, the reduction treatment time is 0.1 min to 60 min. Specifically, the reduction treatment time includes, but is not limited to: 0.1 min, 0.5 min, 1 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, or any range between the foregoing.

[0073] Without restriction, stirring can also be performed during the reduction process to ensure a more thorough and rapid reduction.

[0074] In some other embodiments, the reducing agent used in the reduction treatment includes an organic reducing agent. Further, the organic reducing agent includes one or more of glucose, ascorbic acid, phenol, catechol, hydroquinone, and citric acid.

[0075] As an example, the principle of glucose reducing ferric ions is to utilize the reducing property of glucose to reduce ferric ions to ferrous ions, during which glucose itself is oxidized to aldehydes and ketoses. The specific reaction process is shown in equations (9) and (10):

[0076] (9)

[0077] (10)

[0078] As an example, the principle of ascorbic acid reduction of ferric ions is to utilize the reducing property of ascorbic acid to reduce ferric ions to ferrous ions. During the reduction process, ascorbic acid itself is oxidized to sucrose. The specific reaction process is as follows (11):

[0079] (11)

[0080] As an example, the principle of phenol reducing ferric ions is to use the reducing property of phenol to reduce ferric ions to ferrous ions. During the reduction process, phenol reacts with ferric ions to generate phenylferric ions and water. The specific reaction process is as follows (12):

[0081] (12)

[0082] Formulas (9), (11), and (12) can be used to counteract the ferric ions generated by the anodic reaction (1).

[0083] In some embodiments, the mass ratio of the organic reducing agent to the electroplating solution is 1:(100~100000). Specifically, the mass ratio of the inorganic reducing agent to the electroplating solution includes, but is not limited to: 1:100, 1:500, 1:1000, 1:2000, 1:5000, 1:10000, 1:50000, and 1:100000. Using a reasonable amount of organic reducing agent can achieve a good reduction effect while avoiding the introduction of excessive additives, which could affect subsequent filtration and separation, and reduce the amount of additives entering the electroplating step.

[0084] In some embodiments, the filtration process uses activated carbon as the filter medium. Using a suitable filter medium can effectively remove both reacted and unreacted organic matter, reducing its adverse effects on the plating layer and resulting in a plating layer with better strength and bending resistance.

[0085] In some embodiments, the reduction treatment temperature is 0°C to 100°C. Specifically, the reduction treatment temperature includes, but is not limited to: 0°C, 10°C, 20°C, 50°C, 80°C, 100°C, or any range between the foregoing.

[0086] Furthermore, the reduction treatment time can be adjusted according to the activity of the reducing agent. In some embodiments, the reduction treatment time is 0.1 min to 30 min. The reduction treatment time is 0.1 min to 60 min. Specifically, the reduction treatment time includes, but is not limited to: 0.1 min, 0.5 min, 1 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, or any range between the foregoing.

[0087] Without restriction, stirring can also be performed during the reduction process to ensure a more thorough and rapid reduction.

[0088] In some embodiments, an additive replenishment step is included between the filtration process and the electroplating process. The added additives include one or more of the following: primary brightener, secondary brightener, wetting agent, and complexing agent. After the electroplating solution is filtered by activated carbon, some of the electroplating additives are adsorbed and lost. This additive replenishment step can be added to maintain a balance of additive content in the electroplating solution. Understandably, the primary brightener, secondary brightener, wetting agent, and complexing agent used here should be consistent with the materials in the original electroplating solution.

[0089] Without limitation, the material of the insoluble anode includes titanium metal. Specifically, it can be, for example, a titanium metal mesh. Optionally, its surface may be provided with an anti-oxidation coating, the material of which is, for example, platinum, iridium-tantalum alloy, ruthenium-iridium alloy, rhodium, etc.

[0090] Without limitation, the cathode material includes titanium metal. Specific examples include titanium rollers, titanium foil, etc.

[0091] Understandably, the electroplating solution may be an electroplating solution used in the art for conventional nickel-iron alloy foils.

[0092] In some embodiments, the electroplating solution comprises a main salt and additives.

[0093] Furthermore, the divalent nickel salt in the main salt can be one or both of nickel sulfate and nickel chloride, and the divalent ferric salt can be ferrous sulfate.

[0094] Further, the additives may include one or more of the following: a complexing agent, a stabilizer, a pH buffer, a primary brightener, a secondary brightener, and a wetting agent. Without limitation, the complexing agent includes one or more of citric acid, sodium citrate, sodium gluconate, and gluconic acid; the stabilizer includes one or more of hydroquinone, catechol, o-phenylenediamine, and p-phenylenediamine; the pH buffer includes boric acid; the primary brightener includes saccharin; the secondary brightener includes one or two of 1,4-butynediol and 791 brightener; and the wetting agent includes one or two of sodium dodecylbenzenesulfonate and sodium dodecyl sulfate.

[0095] In some embodiments, the electroplating solution comprises:

[0096] Nickel sulfate 150g / L ~300g / L, nickel chloride 30g / L ~60g / L, ferrous sulfate 1g / L ~90g / L, pH buffer 20g / L ~70g / L, complexing agent 20g / L ~60g / L, stabilizer 5g / L ~20g / L, primary brightener 2g / L ~15g / L, secondary brightener 0.2g / L ~1g / L, and wetting agent 0.01g / L ~1g / L.

[0097] In some embodiments, the pH of the electroplating solution is 1.5 to 4.

[0098] In addition, without limitation, the electroplating parameters include: a current density of 2A / dm³. 2 ~20A / dm 2 The temperature is 30℃~70℃.

[0099] In other embodiments of this application, an apparatus for preparing nickel-iron alloy foil is provided, such as... Figure 1 As shown, the device includes an electroplating apparatus 200, a reduction apparatus 300, and a filter 400, which are connected in sequence by a pipeline 100. A reducing agent is placed in the reduction apparatus 300.

[0100] Understandably, when the reducing agent is an inorganic reducing agent, it can be directly used as follows: Figure 1 The apparatus shown is for a nickel-iron alloy foil. Further, the filter medium of filter 400 comprises a fibrous material. Further, the fibrous material comprises one or more of polyester fiber, glass fiber, and flax fiber.

[0101] Understandably, when the reducing agent is an organic reducing agent, in Figure 1 Based on this, an additive replenishment device 500 is installed, specifically as follows: Figure 2 As shown, the device includes an electroplating apparatus 200, a reduction apparatus 300, a filter 400, and an additive replenishment apparatus 500, which are connected in sequence by a pipeline 100. A reducing agent is added to the reduction apparatus 300.

[0102] Furthermore, the filter medium of filter 400 includes activated carbon.

[0103] Understandably, the apparatus for preparing nickel-iron alloy foil is used to prepare nickel-iron alloy foil according to the above preparation method, and has similar schemes and advantages, which will not be elaborated here.

[0104] In other embodiments of this application, a current collector is provided, comprising a nickel-iron alloy foil prepared by the preparation method described above. The nickel-iron alloy foil prepared by the preparation method described above has a relatively uniform thickness and relatively high strength, and is particularly suitable for battery systems with high silicon (silicon-based material mass percentage ≥20% in the negative electrode active material) negative electrode.

[0105] Understandably, the current collector is a negative electrode current collector, which can be a single nickel-iron alloy foil or a negative electrode current collector. The composite current collector may include a polymer material substrate and a nickel-iron alloy foil formed on at least one surface of the polymer material substrate. Non-limiting examples of the polymer material substrate may include one or more of the following substrates: polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0106] In other embodiments of this application, an electrode is provided, comprising the current collector as described above.

[0107] Understandably, the electrode is a negative electrode. The negative electrode includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, the negative active material layer comprising a negative active material.

[0108] As a non-limiting example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0109] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0110] In some embodiments, the negative electrode active material layer may optionally include a binder. The binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0111] In some embodiments, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0112] In some embodiments, the negative electrode active material layer may also optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0113] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder, and any other components, in a solvent (a non-limiting example of a solvent is deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto at least one surface of a negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing, and other processes. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 40wt%~60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000mPa·s~10000mPa·s. When coating the negative electrode slurry, the coating unit areal density (dry weight, deducting solvent) can be 75g / m². 2 ~220g / m 2 The compaction density of the negative electrode sheet can be 1.0 g / cm³. 3 ~ 1.8g / cm 3 .

[0114] In other embodiments of this application, a battery is provided, including a current collector as described above or an electrode as described above.

[0115] In other embodiments of this application, an electrical device is provided, including a current collector, electrode, or battery as described above.

[0116] The battery and power supply device of this application will be described below with appropriate reference to the accompanying drawings.

[0117] Typically, a battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and releasing. The electrolyte acts as a conductor between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.

[0118] The negative electrode is as described above.

[0119] The positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0120] As a non-limiting example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0121] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be obtained by forming a metal material on a polymer material substrate. Non-limiting examples of the metal material in the positive electrode current collector may include one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limiting examples of the polymer material substrate in the positive electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0122] In some embodiments, the positive electrode active material may be a known positive electrode active material for batteries. As a non-limiting example, the positive electrode active material may include one or more of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their modified compounds. Non-limiting examples of lithium-containing phosphates with an olivine structure include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium manganese iron phosphate and carbon composites. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 Examples of lithium nickel cobalt aluminum oxides include LiNi, etc. 0.8 Co 0.15 Al 0.05 O2.

[0123] In some embodiments, the positive electrode active material layer may optionally include a binder. As a non-limiting example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0124] In some embodiments, the positive electrode active material layer may optionally include a conductive agent. As a non-limiting example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0125] In some embodiments, the positive electrode sheet can be prepared by dispersing the components used to prepare the positive electrode sheet, such as the positive electrode active material, conductive agent, binder, and any other components, in a solvent to form a positive electrode slurry; coating the positive electrode slurry onto at least one surface of the positive electrode current collector, and then obtaining the positive electrode sheet through processes such as drying and cold pressing. The solvent can be selected from, but is not limited to, any of the solvents described in the foregoing embodiments, such as N-methylpyrrolidone (NMP). The surface of the positive electrode current collector coated with the positive electrode slurry can be a single surface or both surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40wt% to 80wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000 mPa·s to 25000 mPa·s. When coating the positive electrode slurry, the coating areal density per unit area (dry weight, minus solvent) can be 15 mg / cm³. 2 ~35mg / cm 2 The compaction density of the positive electrode sheet can be 3.0 g / cm³. 3 ~3.6g / cm 3 3.3g / cm³ is an option. 3 ~3.5g / cm 3 .

[0126] Electrolytes function to conduct ions between the positive and negative electrode plates. This application does not impose any particular restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or completely solid.

[0127] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution comprises an electrolyte salt and a solvent.

[0128] In some embodiments, the electrolyte salt may include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorophosphate (LiPO2F2), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0129] In some embodiments, the solvent may include ethylene carbonate (EC, ), propylene carbonate (PC, ), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butene carbonate ( One or more of the following: fluoroethylene carbonate (FEC), methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0130] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0131] In some embodiments, the additives in the electrolyte may include, but are not limited to, one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), trifluoromethyl ethylene carbonate (TFPC), etc.

[0132] In some embodiments, the battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0133] In some embodiments, the material of the separator may include one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0134] In some embodiments, the thickness of the isolation membrane is 6μm to 40μm, and optionally 12μm to 20μm.

[0135] In some embodiments, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0136] In some embodiments, the battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0137] In some embodiments, the battery's outer packaging can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The battery's outer packaging can also be a soft pack, such as a pouch. The soft pack can be made of plastic; further, non-limiting examples of plastic may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0138] A battery includes at least one battery cell. A battery may include one or more battery cells.

[0139] In this application, unless otherwise specified, "cell battery" refers to the basic unit capable of converting chemical energy into electrical energy, and generally includes at least a positive electrode, a negative electrode, and an electrolyte. During the charging and discharging process of the battery, active ions move back and forth between the positive and negative electrode plates, inserting and extracting. The electrolyte acts as a conductor for the active ions between the positive and negative electrode plates.

[0140] This application does not impose any particular limitation on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 3 This is a square-structured battery 1 used as an example.

[0141] In some of these implementations, reference is made to... Figure 4 The outer packaging may include a housing 11 and a cover plate 13. The housing 11 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 11 has an opening communicating with the receiving cavity, and the cover plate 13 can be placed over the opening to close the receiving cavity. The positive electrode, negative electrode, and separator may be formed into an electrode assembly 12 by a winding process or a stacking process. The electrode assembly 12 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 12. The battery 1 may contain one or more electrode assemblies 12, which can be selected by those skilled in the art according to actual needs.

[0142] The battery can be a battery module or a battery pack.

[0143] A battery module includes at least one battery cell. The number of battery cells in a battery module can be one or more, and those skilled in the art can select an appropriate number based on the application and capacity of the battery module.

[0144] In a battery module, multiple battery cells can be arranged sequentially along the length of the module. Of course, they can also be arranged in any other manner. Furthermore, these battery cells can be secured using fasteners.

[0145] Optionally, the battery module may also include a housing with a receiving space in which multiple battery cells are housed.

[0146] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the battery pack may contain one or more battery modules. Those skilled in the art can select an appropriate number based on the application and capacity of the battery pack.

[0147] The battery pack may include a battery box and multiple battery modules disposed within the battery box. The battery box includes an upper body and a lower body, with the upper body covering the lower body to form a closed space for accommodating the battery modules. The multiple battery modules can be arranged in any manner within the battery box.

[0148] In addition, this application also provides an electrical device, which includes the battery provided in this application. The battery can be used as a power source for the electrical device or as an energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Among them, mobile devices may be, for example, mobile phones, laptops, etc.; electric vehicles may be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc., but are not limited to.

[0149] As an electrical device, the battery can be selected according to its usage requirements.

[0150] Figure 5 Here is an example of an electrical device 2. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device, a battery pack or battery module can be used.

[0151] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source.

[0152] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0153] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0154] Example 1

[0155] Adopting such Figure 1 The apparatus shown is used to prepare nickel-iron alloy foil.

[0156] Electroplating apparatus 200:

[0157] The anode is a titanium mesh with a ruthenium-iridium alloy coating on its surface, and the cathode is a titanium roller.

[0158] The electroplating solution consists of (water as solvent): nickel sulfate 200 g / L, nickel chloride 40 g / L, ferrous sulfate 50 g / L, boric acid 40 g / L, citric acid 30 g / L (complexing agent), hydroquinone 10 g / L (stabilizer), saccharin 3 g / L (primary brightener), 1,4-butynediol 0.5 g / L (secondary brightener), and sodium dodecyl sulfate 0.1 g / L (wetting agent).

[0159] Electroplating parameters are: current density 10A / dm 2 Temperature 50℃, pH 2.5.

[0160] During electroplating, the electroplating solution is circulated sequentially between the electroplating device 200, the reduction device 300, and the filter 400; ferrous sulfide is added to the reduction device 300 at a mass ratio of 1:1000 to the electroplating solution; the filter medium in the filter 500 is polyester fiber.

[0161] The temperature of the reduction device 300 is 50°C, and the reaction time of the electroplating solution in it is 40 seconds.

[0162] A nickel-iron alloy film is formed by electroplating on a titanium roller, and then peeled off to obtain a nickel-iron alloy foil with a thickness of 6μm.

[0163] The above preparation method can continuously produce long rolls of nickel-iron alloy foil with a length of ≥5000m.

[0164] Example 2

[0165] The preparation method of the nickel-iron alloy foil provided in this embodiment is the same as that in Embodiment 1, the main difference being that ferrous sulfide is replaced with an equal amount of ammonium sulfide.

[0166] Example 3

[0167] The preparation method of the nickel-iron alloy foil provided in this embodiment is the same as that in Embodiment 1, the main difference being that ferrous sulfide is replaced with an equal amount of sodium sulfite.

[0168] Example 4

[0169] Adopting such Figure 2 The apparatus shown is used to prepare nickel-iron alloy foil.

[0170] Electroplating apparatus 200:

[0171] The anode is a titanium mesh with a ruthenium-iridium alloy coating on its surface, and the cathode is a titanium roller.

[0172] The composition of the electroplating solution and the electroplating parameters are the same as in Example 1.

[0173] During electroplating, the electroplating solution is circulated sequentially between the electroplating device 200, the reduction device 300, the filter 400, and the additive replenishment device 500; glucose is added to the reduction device 300 at a mass ratio of 1:1000 to the electroplating solution; activated carbon is used as the filter medium in the filter 500.

[0174] The reduction device 300 has a temperature of 55°C and a reaction time of 40 seconds in the electroplating solution. The additive replenishment device 500 is equipped with an automatic additive replenishment system, which can automatically replenish the amount of plating solution additives consumed by activated carbon filtration. For every liter of plating solution filtered, 0.2g of saccharin (primary brightener), 0.05g of 1,4-butynediol (secondary brightener), and 0.02g of sodium dodecyl sulfate (wetting agent) are added.

[0175] A nickel-iron alloy film is formed by electroplating on a titanium roller, and then peeled off to obtain a nickel-iron alloy foil with a thickness of 6μm.

[0176] Example 5

[0177] The preparation method of the nickel-iron alloy foil provided in this embodiment is the same as that in Embodiment 4, the main difference being that glucose is replaced with an equal amount of phenol.

[0178] Comparative Example 1

[0179] The preparation method of the nickel-iron alloy foil provided in this comparative example is the same as that in Example 1, the main difference being that: the reduction device 300 and the filter 400 are not set up, that is, the electroplating solution is not circulated; ferrous sulfide is directly added to the electroplating device 100 in the specified amount and electroplating is performed according to the electroplating parameters.

[0180] Comparative Example 2

[0181] The preparation method of the nickel-iron alloy foil provided in this comparative example is the same as that in Example 5, the main difference being that: the reduction device 300 and the filter 400 are not set up, that is, the electroplating solution is not circulated; phenol is directly added to the electroplating device 100 according to the electroplating parameters for electroplating.

[0182] Test example:

[0183] (1) Concentration test of ferric ions in electroplating solution

[0184] Test method: Pipette 2 mL of electroplating solution into a 250 mL Erlenmeyer flask, add 5 mL of 50% hydrochloric acid; add 1 g of potassium iodide, shake well, add 50 mL of 70℃ hot water, add 1 mL of 1% starch indicator, and it turns blue; titrate with 0.01 mol / L sodium thiosulfate standard solution until the blue color disappears, and record the volume of sodium thiosulfate consumed, V (mL).

[0185] P(Fe 3+ =MV × 55.85 / 2 (g / L)

[0186] Note: M represents the concentration of sodium thiosulfate standard solution.

[0187] (2) Tensile strength test

[0188] Test method: According to GB / T 5230-1995 "Electrolytic Copper Foil", tensile specimens were cut into length L0 of 200 mm and width of 15 mm. The specimens were weighed on a balance and the mass was recorded as m. Tensile properties were tested using a universal testing machine at 25℃, with the tensile rate set to 50 mm / min. The cross-sectional area S0 of the tensile specimen is then calculated as S0 = m / (ρ × L0), where ρ is 8.96 g / cm³. 3 The unit of m is grams, and the unit of L0 is centimeters. The specimen is continuously loaded until it breaks. The maximum load F is read from the force gauge or the tensile curve, and the tensile strength σb is calculated according to formula (Ⅰ):

[0189] σb=F / S0 (Ⅰ).

[0190] The distance between the two lines after the specimen breaks is L1, which can be measured on the specimen or read from the tensile curve. L1 can be measured using the linear method or the displacement method, and the elongation at break δ can be calculated according to formula (II):

[0191] δ=(L1-L0) / L0 (Ⅱ).

[0192] (3) Thickness uniformity test: The cross-sectional sample of the current collector was prepared by liquid nitrogen quenching. The secondary electronic phase morphology of the current collector cross-section was observed and the thickness was measured by scanning electron microscopy (1000-30000 times magnification). The minimum resolution can reach the nanometer level. The thickness of the foil was measured at 10 points at equal intervals perpendicular to the tape direction, and the thickness range was calculated.

[0193] The test results are shown in Table 1:

[0194] Table 1

[0195]

[0196] As can be seen from the comparison between Examples 1-3 and Comparative Example 1, and Examples 4-5 and Comparative Example 2, this application, when using an insoluble anode, can significantly reduce the concentration of ferric ions in the electroplating solution by setting up a reduction device and a filter, that is, by performing reduction and filtration treatment on the plating solution during the electroplating process, thereby improving the electroplating effect and enhancing the strength, bending resistance, and thickness uniformity of the prepared nickel-iron alloy foil.

[0197] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0198] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a nickel-iron alloy foil, characterized in that, Includes the following steps: An insoluble anode, an electroplating solution, and a cathode are provided for electroplating treatment, forming a nickel-iron alloy film on the surface of the cathode; The main salts of the electroplating solution include divalent nickel salt and divalent iron salt; during the electroplating process, the electroplating solution is circulated sequentially for electroplating, reduction treatment and filtration treatment, and the concentration of trivalent iron ions in the electroplating solution is ≤1g / L; The nickel-iron alloy film is separated from the surface of the cathode to prepare a nickel-iron alloy foil.

2. The method for preparing nickel-iron alloy foil according to claim 1, characterized in that, The reducing agent used in the reduction treatment includes an inorganic reducing agent; optionally, the inorganic reducing agent includes one or more of sulfides and sulfurous compounds. Further optionally, the sulfide includes one or more of hydrogen sulfide, ammonium sulfide, ferrous sulfide, ferric disulfide, nickel sulfide, and sodium sulfide; Further optionally, the sulfurous compound includes one or more of sulfurous acid, ammonium sulfite, sodium sulfite, and potassium sulfite.

3. The method for preparing nickel-iron alloy foil according to claim 2, characterized in that, The mass ratio of the inorganic reducing agent to the electroplating solution is 1:(100~100000).

4. The method for preparing nickel-iron alloy foil according to claim 2 or 3, characterized in that, The filtration process uses a filter medium that includes fibrous materials, which may optionally include one or more of polyester fibers, glass fibers, and flax fibers.

5. The method for preparing nickel-iron alloy foil according to any one of claims 2 to 4, characterized in that, The reduction treatment temperature is 0℃~100℃; and / or The reduction process takes 0.1 min to 60 min.

6. The method for preparing nickel-iron alloy foil according to claim 1, characterized in that, The reducing agent used in the reduction treatment includes organic reducing agents; Optionally, the organic reducing agent includes one or more of glucose, ascorbic acid, phenol, catechol, hydroquinone, and citric acid; Optionally, the mass ratio of the organic reducing agent to the electroplating solution is 1:(100~100000).

7. The method for preparing nickel-iron alloy foil according to claim 6, characterized in that, The filtration process uses activated carbon as the filter medium.

8. The method for preparing nickel-iron alloy foil according to claim 6 or 7, characterized in that, The reduction treatment temperature is 0℃~100℃; and / or The reduction process takes 0.1 min to 30 min.

9. The method for preparing nickel-iron alloy foil according to any one of claims 6 to 8, characterized in that, The process between filtration and electroplating also includes an additive addition step, whereby the additives include one or more of the following: primary brightener, secondary brightener, wetting agent, and complexing agent.

10. An apparatus for preparing nickel-iron alloy foil, characterized in that, The device includes an electroplating unit, a reduction unit, and a filter, which are connected in sequence by pipelines, and the reduction unit includes a reducing agent. Optionally, an additive replenishment device is also provided between the filter and the electroplating device.

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