Metal foil, negative electrode material for battery, and battery

Abstract

The application discloses a metal foil, a negative electrode material applied to a battery and the battery. The metal foil comprises at least one non-conductive support body and conductive layers respectively arranged on two surfaces of the support body, namely a first conductive layer and a second conductive layer. A side surface of the first conductive layer away from the support body is a first surface, and a side surface of the second conductive layer away from the support body is a second surface. A roughness Rz(at) of the first surface in a TD direction is equal to or greater than a roughness Rz(am) of the first surface in an MD direction. A roughness Rz(bt) of the second surface in the TD direction is equal to or greater than a roughness Rz(bm) of the second surface in the MD direction. By optimizing the roughness of the surface of the metal foil, the uniformity and rationality of the structural performance of the surface of the metal foil are effectively improved, and the quality of the metal foil and products applying the metal foil is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal foils, and in particular to a metal foil, a negative electrode material used for a battery, and a battery. Background Art

[0002] With the rapid development of the electronics industry, metal foil has been widely used in printed circuit boards, battery negative electrode materials, chip packaging and other fields. As the current collector of the negative electrode of new energy batteries, metal foil is the core raw material for making new energy batteries. The development of its production technology and the quality of its performance directly affect the manufacturing process, performance and production cost of new energy batteries.

[0003] To address the problem of excessive thickness and weight hindering the improvement of battery energy density, existing negative electrode materials for new energy batteries often use organic films such as PET as a support, with conductive layers formed into metal foil on both sides of the support. However, the inventors have discovered that the prior art has at least the following problems: Because the PET and other organic material films are too thin, they are prone to adhesion and bonding during production, resulting in wrinkles or fine streaks. Furthermore, the resulting wrinkles and fine streaks are mostly distributed along the MD direction (parallel to the conveying direction of the production line), causing the surface roughness in the TD direction (perpendicular to the conveying direction of the production line) in the wrinkled area to increase. The TD direction roughness is much greater than the MD direction roughness, resulting in uneven structural properties on both sides of the metal foil in the MD and TD directions. The metal foil surface also exhibits significant unevenness, which is prone to warping and other problems, negatively impacting the adhesion of the negative electrode active material. The presence of wrinkles and fine streaks seriously affects the uniform spreading of the negative electrode active material on the copper foil surface, resulting in uneven thickness of the active material after spreading, which can cause imbalance in the subsequent electrochemical reaction process. Furthermore, in some wrinkled areas, the negative electrode active material cannot effectively penetrate and evenly spread within the wrinkled areas. Furthermore, more negative electrode active material accumulates in the "grooves" of the stripes, while it is more difficult to apply negative electrode material to the "raised" areas of the stripes. Specifically, more negative electrode material is applied to the grooves, while less is applied to the raised areas. This can easily lead to uneven gaps between the active material on the negative electrode current collector and the battery separator and positive electrode. This can also cause the lithium ions in the battery's chemical reactions to move along different paths, negatively impacting the balance of the battery's chemical reactions. Furthermore, in areas with a high concentration of negative electrode active material, excessive lithium ion accumulation can lead to excessive heat generation, resulting in uneven heat distribution within the battery's chemical reactions. This increases the probability of expansion and bulging in overheated areas, which in turn reduces battery safety, stability, and reliability. Furthermore, the presence of uneven surface roughness and wrinkles can also negatively impact the material production process. For example, the metal foil can easily stick to the roller surface and tilt during conveying and winding, creating more wrinkles. Therefore, the uniformity of the structural properties in the MD and TD directions of the metal foil surface and between the upper and lower surfaces plays a key role in the quality of the metal foil and even the product quality when the metal foil is used as the negative electrode material of new energy batteries. Summary of the Invention

[0004] In order to solve the various problems mentioned above, the purpose of the embodiments of the present invention is to provide a metal foil, a negative electrode material for a battery, and a battery. By optimizing the surface morphology of the metal foil, the uniformity and rationality of the structural performance of the metal foil surface are effectively improved, and the quality of the metal foil and the products using the metal foil is improved.

[0005] To achieve the above-mentioned purpose, an embodiment of the present invention provides a metal foil, comprising at least one non-conductive support, and conductive layers respectively located on two surfaces of the support, namely a first conductive layer and a second conductive layer, wherein the surface of the first conductive layer on the side away from the support is the first surface, and the surface of the second conductive layer on the side away from the support is the second surface; the roughness Rz(at) of the first surface in the TD direction is equal to or greater than the roughness Rz(am) of the first surface in the MD direction; the roughness Rz(bt) of the second surface in the TD direction is equal to or greater than the roughness Rz(bm) of the second surface in the MD direction.

[0006] As an improvement to the above solution, the ratio of the roughness Rz(am) of the first surface in the MD direction to the roughness Rz(at) of the first surface in the TD direction is between between;

[0007] and / or, the ratio of the roughness Rz(bm) in the MD direction of the second surface to the roughness Rz(bt) in the TD direction of the second surface is between between.

[0008] As an improvement to the above solution, the ratio of the root mean square roughness Rq(am) in the MD direction of the first surface to the root mean square roughness Rq(at) in the TD direction of the first surface is between;

[0009] And / or, the ratio of the root mean square roughness Rq(bm) in the MD direction of the second surface to the root mean square roughness Rq(bt) in the TD direction of the second surface is in the range of between.

[0010] As an improvement to the above solution, the ratio of the arithmetic mean roughness Ra (am) in the MD direction of the first surface to the arithmetic mean roughness Ra (bm) in the MD direction of the second surface is between between;

[0011] And / or, the ratio of the arithmetic average roughness Ra(at) in the TD direction of the first surface to the arithmetic average roughness Ra(bt) in the TD direction of the second surface is in between.

[0012] As an improvement of the above solution, the thickness H of the metal foil is ≤ 12 μm.

[0013] As an improvement of the above solution, the thickness of the support is less than or equal to 10 μm.

[0014] As an improvement to the above solution, the metal foil also includes metal padding layers located on both surfaces of the support, namely a first metal padding layer and a second metal padding layer. The first metal padding layer is located between the support and the first conductive layer, and the second metal padding layer is located between the support and the second conductive layer.

[0015] As an improvement of the above solution, the elastic modulus of the metal pad layer in the MD direction is greater than the elastic modulus of the metal pad layer in the TD direction, and the roughness Rz of the metal pad layer is between 0.6 and 2.5 μm.

[0016] As an improvement of the above scheme, the material of the conductive layer includes at least one metal selected from the group consisting of copper, aluminum, iron, zinc, titanium, cobalt, gold, silver, nickel, chromium, indium, gallium, tin, thallium, lead, bismuth, germanium, antimony, polonium, beryllium, magnesium, calcium, strontium, barium, radium, lanthanide metals, actinide metals and transition metals and / or an alloy formed by at least one of them.

[0017] As an improvement of the above solution, the metal foil further includes an anti-oxidation layer, which is located on at least one surface of the conductive layer and has a thickness of 0.8% to 30% of the thickness of the conductive layer.

[0018] An embodiment of the present invention provides a negative electrode material for a battery, the negative electrode material comprising a negative electrode active material and the metal foil according to any one of the above claims, wherein the metal foil is tightly bonded to the negative electrode active material.

[0019] As an improvement to the above solution, the support in the metal foil is an insulating material.

[0020] An embodiment of the present invention provides a battery, wherein the negative electrode material of the battery is the negative electrode material applied to the battery as described above.

[0021] Compared with the prior art, the metal foil, the negative electrode material for use in a battery, and the battery disclosed in the embodiments of the present invention include at least one non-conductive support and conductive layers respectively located on two surfaces of the support, namely a first conductive layer and a second conductive layer. The surface of the first conductive layer on the side away from the support is the first surface, and the surface of the second conductive layer on the side away from the support is the second surface. The roughness Rz(at) of the first surface in the TD direction is equal to or slightly greater than the roughness Rz(am) of the first surface in the MD direction. The roughness Rz(bt) of the second surface in the TD direction is equal to or slightly greater than the roughness Rz(bm) of the second surface in the MD direction. According to the embodiment of the present invention, by controlling the topography of the first surface A and the second surface B, the difference in the roughness parameter Rz of the two outer surfaces of the metal foil in the MD direction and the TD direction is minimized, and by further optimizing the relationship and numerical range of the roughness Rz, the arithmetic mean roughness Ra and the root mean square roughness Rq of the two outer surfaces of the metal foil in the MD direction and the TD direction, combined with improvements in the thickness and structural composition of the metal foil, the structures and properties of the two surfaces in the MD direction and the TD direction are made more uniform, and the wrinkles and fine stripes of the metal foil are significantly reduced, or even if wrinkles and fine stripes exist, the metal foil is smoothed. The micro-streaks are small, but the wrinkles and fine streaks are very small, and the resulting roughness fluctuations are significantly reduced, ensuring the flatness and thickness uniformity of the two surfaces of the metal foil. It is not prone to warping and other problems, effectively improving the quality of the metal foil product, facilitating the uniform spreading and adhesion of the metal foil and the negative electrode material active material, reducing the fluctuation of the overall thickness of the negative electrode material with the active material attached, and avoiding the problems of uneven electrochemical reactions in the battery and excessive local heating. It improves the dimensional stability of the battery material and the balance and reliability of the electrochemical reaction process, and helps improve the electrochemical reaction efficiency, improves the battery energy density, and effectively reduces the weight and thickness of the battery. At the same time, it also reduces the problems of metal foil sticking to the roller surface and tilting during the coating of active reaction materials and winding, improving the product qualification rate and transportation efficiency, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a first metal foil provided by an embodiment of the present invention;

[0023] Figure 2 1 is a schematic structural diagram of a second metal foil provided by an embodiment of the present invention;

[0024] Figure 3 1 is a schematic structural diagram of a third metal foil provided by an embodiment of the present invention;

[0025] Figure 4 1 is a schematic structural diagram of a fourth metal foil provided by an embodiment of the present invention;

[0026] Figure 5 1 is a schematic structural diagram of a fifth metal foil provided by an embodiment of the present invention;

[0027] Figure 6 1 is a schematic structural diagram of a sixth metal foil provided by an embodiment of the present invention;

[0028] Among them, 1. support; 2. conductive layer; 21. first conductive layer; 22. second conductive layer; 3. metal pad layer; 31. first metal pad layer; 32. second metal pad layer; 4. anti-oxidation layer; 5. bonding layer. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] In the description of the specification and claims, it should be understood that the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0031] Furthermore, the terms "first," "second," and so on, in the specification and claims, are used solely for descriptive purposes to distinguish between identical technical features and are not to be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referenced, nor do they necessarily describe a sequential or chronological order. The terms are interchangeable where appropriate. Thus, a feature qualified as "first" or "second" may explicitly or implicitly include at least one of those features.

[0032] See also Figure 1 , is a schematic diagram of the structure of a first metal foil provided by an embodiment of the present invention. The embodiment of the present invention provides a metal foil comprising at least one non-conductive support 1, and conductive layers 2, namely a first conductive layer 21 and a second conductive layer 22, located on two surfaces of the support.

[0033] The metal foil of the embodiment of the present invention is formed by providing at least one support 1 and disposing a conductive layer 2 on both surfaces of the support 1. Compared to the metal foil formed by stacking multiple metal layers in the prior art, the thickness and weight of the metal foil of the embodiment of the present invention can be significantly reduced, avoiding excessive density, thickness, and weight of the metal foil. Moreover, when the metal foil is used as the negative electrode material of a new energy battery, the three-layer structure design provides active materials for the battery reaction on the surfaces of the conductive layers on both sides of the support, allowing the metal foil and the negative electrode material to fully undergo an electrochemical reaction, improving the utilization rate of the battery's negative electrode material and effectively increasing the battery's energy density. At the same time, the three-layer symmetrical structure is more beneficial and stable for the battery's material properties and electrochemical reactions as a whole.

[0034] It should be noted that, in practical applications, the metal foil is preferably used in the field of new energy batteries. Of course, the metal foil can also be used in many other fields, such as the circuit board field, the semiconductor material field, etc. In an optional embodiment, when the metal foil is used in the field of new energy batteries, the metal foil is used as the negative electrode material of the battery, and is tightly bonded to the negative electrode active material in the negative electrode material through the conductive layer.

[0035] See also Figure 1 , the surface of the first conductive layer 21 away from the support 1 is referred to as the first surface A, and the surface of the second conductive layer 22 away from the support 1 is referred to as the second surface B. Then, the roughness Rz(at) in the TD direction of the first surface A is equal to or slightly greater than the roughness Rz(am) in the MD direction of the first surface A; the roughness Rz(bt) in the TD direction of the second surface B is equal to or slightly greater than the roughness Rz(bm) in the MD direction of the second surface B.

[0036] It should be noted that the MD direction of the metal foil refers to the length direction of the metal foil, that is, parallel to the conveying direction of the production line, and the TD direction of the metal foil refers to the thickness direction of the metal foil, that is, perpendicular to the conveying direction of the production line.

[0037] It should be noted that the roughness Rz is the sum of the average of the n largest profile peak heights and the average of the n largest profile valley depths within the sampling length, where n≥1; preferably, n=5. The roughness Rz can fully reflect the peak height of the profile.

[0038] In an embodiment of the present invention, the relationship between the roughness Rz(am) of the first surface A in the MD direction and the roughness Rz(at) of the first surface A in the TD direction is optimized.

[0039] In the first embodiment, Rz(at)=Rz(am), and the roughness Rz in the TD direction and the MD direction of the first surface A is controlled to be the same, so that the structure and performance of the first surface A in the TD direction and the MD direction are more uniform and consistent, and no wrinkles or fine stripes will be generated during the production process, or even if wrinkles and fine stripes are generated, they are very small, and the resulting roughness fluctuations are significantly reduced.

[0040] In the second embodiment, Rz(at)>Rz(am), and the difference between Rz(at) and Rz(am) is controlled within a certain numerical range, so that Rz(at) is only slightly larger than Rz(am). By controlling the roughness Rz in the TD direction of the first surface A to approach the roughness Rz in the MD direction, the structure and performance of the first surface A in the MD direction and the TD direction tend to be uniform, the wrinkles and fine stripes generated during the production process are very small, and the resulting roughness fluctuations are significantly reduced.

[0041] Likewise, the magnitude relationship between the roughness Rz(bm) of the second surface B in the MD direction and the roughness Rz(bt) of the second surface B in the TD direction is optimized.

[0042] In the first embodiment, Rz(bt)=Rz(bm), and by controlling the roughness Rz of the first surface A in the TD direction and the MD direction to be the same, the structure and performance of the second surface B in the TD direction and the MD direction are made more uniform.

[0043] In the second embodiment, Rz(bt)>Rz(bm), and the difference between Rz(bm) and Rz(bt) is controlled within a certain numerical range, so that Rz(bt) is only slightly larger than Rz(bm). By controlling the roughness Rz in the TD direction of the second surface B to approach the roughness Rz in the MD direction, the structure and performance of the second surface B in the MD direction and the TD direction tend to be uniform.

[0044] By employing the technical means of the embodiments of the present invention, and by controlling the topography, structure, and production process of the first surface A and the second surface B, the roughness Rz of the two outer surfaces of the metal foil in the MD and TD directions tends to be equal or differs very little. The structure and performance of the two surfaces in the MD and TD directions are more uniform and consistent. Wrinkles and fine streaks are eliminated or very small during the production process, resulting in significantly reduced roughness fluctuations. This ensures the flatness and thickness uniformity of the two surfaces of the metal foil, making warping less likely and effectively improving the quality of the metal foil product. When applied to new energy batteries, this facilitates the uniform spreading and adhesion of the metal foil and the active material of the negative electrode material, improves the dimensional stability of the battery material, and the balance and reliability of the electrochemical reaction process. It avoids local overheating, helps improve the electrochemical reaction efficiency, increases the battery energy density, and effectively reduces the weight and thickness of the battery.

[0045] As a preferred embodiment, the ratio of the roughness Rz(am) of the first surface in the MD direction to the roughness Rz(at) of the first surface in the TD direction is between The ratio of the roughness Rz (bm) in the MD direction of the second surface to the roughness Rz (bt) in the TD direction of the second surface is between between.

[0046] In the embodiment of the present invention, the ratio of the roughness Rz of the two surfaces of the metal foil in the MD direction and the TD direction is further optimized, wherein, for the first surface A, The value of For the second surface A, The value of The roughness Rz values ​​of the two surfaces of the metal foil in the MD direction and the TD direction are close to or have tended to the closest ratio, which significantly improves the uniformity of the surface structure and properties of the two surfaces, effectively improves the overall quality of the metal foil product, and further helps to improve the adhesion uniformity of the electrolyte and the negative electrode material active substance on the surface of the metal foil product, ensuring that the thickness fluctuation rate of the metal foil is within a relatively low range. The battery using the metal foil as the negative electrode material has a significantly improved battery energy density, and the battery weight and thickness are relatively low.

[0047] Preferably, Rz(am) is between 1.8 and 3.6 μm, for example, it can be 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.5 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 3.3 μm or 3.6 μm.

[0048] Rz(at) is between 2.4 and 4.5 μm, for example, it can be 2.4 μm, 2.6 μm, 2.8 μm, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.5 μm, 3.8 μm, 4 μm, 4.2 μm or 4.5 μm.

[0049] Rz(bm) is between 2.4 and 3 μm, for example, it can be 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm or 3 μm.

[0050] Rz(bt) is between 3.2 and 4.8 μm, for example, it can be 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4 μm, 4.1 μm, 4.2 μm, 4.5 μm or 4.8 μm.

[0051] By using the technical means of the embodiments of the present invention, the size and ratio of the roughness Rz of the two surfaces of the metal foil in the MD direction and the TD direction are optimized, making the distribution of the roughness Rz of the two surfaces of the metal foil in the MD direction and the TD direction more uniform and reasonable. During the production process, no wrinkles or fine streaks are generated, or the wrinkles and fine streaks that are generated are very small. The resulting roughness fluctuations are significantly reduced, and the fluctuations are all within an optimal and reasonable range. This ensures the flatness and thickness uniformity of the two surfaces of the metal foil, making it less prone to warping and other problems. This effectively improves the quality of the metal foil product, which is beneficial for use as a negative electrode material for new energy batteries to improve the quality of the battery. At the same time, it also reduces the problems of sticking to the roller and tilting during the coating of active materials and winding. It improves the conveying efficiency and product yield of the battery negative electrode material production process.

[0052] As a preferred embodiment, the embodiment of the present invention is further implemented on the basis of any of the above embodiments, and the ratio of the root mean square roughness Rq(am) in the MD direction of the first surface to the root mean square roughness Rq(at) in the TD direction of the first surface is The ratio of the root mean square roughness Rq (bm) in the MD direction of the second surface to the root mean square roughness Rq (bt) in the TD direction of the second surface is between between.

[0053] Preferably, Rq(am) is between 0.4 and 0.96, for example, it can be 0.4 μm, 0.5 μm, 0.6 μm, 0.65 μm, 0.7 μm, 0.75 μm, 0.8 μm, 0.85 μm, 0.9 μm or 0.96 μm.

[0054] Rq(at) is between 0.56 and 1.54 μm, for example, it can be 0.56 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.15 μm, 1.2 μm, 1.25 μm, 1.3 μm, 1.35 μm, 1.45 μm or 1.54 μm.

[0055] Rq(bm) is between 0.4 and 0.98, for example, it can be 0.4μm, 0.5μm, 0.6μm, 0.65μm, 0.7μm, 0.75μm, 0.8μm, 0.85μm, 0.9μm or 0.98μm.

[0056] Rq(bt) is between 0.56 and 1.48, for example, it can be 0.56μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.15μm, 1.2μm, 1.25μm, 1.3μm, 1.35μm, 1.4μm or 1.48μm.

[0057] It should be noted that the root mean square roughness Rq is specifically the root mean square value of the contour ordinate value Z(x) within a sampling length. The ordinate value Z(x) refers to the distance from each point on the contour to the contour centerline, which can fully reflect the height characteristics of the surface micro-geometry.

[0058] In an embodiment of the present invention, by controlling the values ​​of the root mean square roughness Rq of the two surfaces of the metal foil in the MD direction and the TD direction to be close to or approaching the closest ratio within their respective preferred ranges, the distribution of the root mean square roughness Rq of the two surfaces of the metal foil in the MD direction and the TD direction is made more uniform and reasonable, thereby further improving the uniformity of the surface structure and properties of the two surfaces, ensuring the flatness and thickness uniformity of the two surfaces of the metal foil, and making it less prone to problems such as warping. Moreover, when the size and ratio of the roughness Rz of the two surfaces of the metal foil in the MD direction and the TD direction meet the preferred range of the above embodiment, the ratio and size between the root mean square roughness Rq of the two surfaces of the metal foil in the MD direction and the TD direction are further optimized. The roughness characteristics of the roughened surface are characterized by combining the root mean square roughness Rq and the roughness Rz, which not only fully reflects the height characteristics of the surface micro-geometry of the metal foil, but also fully reflects the peak height of the profile of the roughened surface, making the roughness of the metal foil surface more reasonable, effectively improving the overall quality of the metal foil product, and further helping to improve the adhesion uniformity of the electrolyte and the negative electrode material active substance on the surface of the metal foil product, ensuring that the thickness fluctuation rate of the metal foil is within a lower range, and the battery using the metal foil as the negative electrode material has a significantly improved battery energy density, and the battery weight and thickness are both low, thereby improving the quality of the battery.

[0059] As a preferred embodiment, the embodiment of the present invention is further implemented on the basis of any of the above embodiments, and the ratio of the roughness Rz (am) of the first surface in the MD direction to the arithmetic average roughness Ra (am) of the first surface in the MD direction is The ratio of the roughness Rz(at) in the TD direction of the first surface to the arithmetic average roughness Ra(at) in the TD direction of the first surface is between between.

[0060] Furthermore, the ratio of the roughness Rz (bm) of the second surface in the MD direction to the arithmetic mean roughness Ra (bm) of the second surface in the MD direction is between The ratio of the roughness Rz(bt) in the TD direction of the second surface to the arithmetic average roughness Ra(bt) in the TD direction of the second surface is between between.

[0061] Preferably, Ra(am) is between 0.24 and 0.82, for example, it can be 0.24 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.65 μm, 0.7 μm, 0.75 μm, 0.78 μm or 0.82 μm.

[0062] Ra(at) is between 0.48 and 1.26 μm, for example, it can be 0.48 μm, 0.56 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.15 μm, 1.2 μm or 1.26 μm.

[0063] Ra(bm) is between 0.28 and 0.86, for example, it can be 0.24μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.65μm, 0.7μm, 0.75μm, 0.8μm or 0.86μm.

[0064] Ra(bt) is between 0.48 and 1.40, for example, it can be 0.48μm, 0.55μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.15μm, 1.2μm, 1.25μm, 1.3μm, 1.35μm or 1.4μm.

[0065] It should be noted that the arithmetic mean roughness (Ra) is the arithmetic mean of the absolute values ​​of the profile's ordinate (Z(x)) within a sampling length. The ordinate (Z(x)) refers to the distance from each point on the profile to the profile's midline. The arithmetic mean roughness (Ra) is used to assess the arithmetic mean deviation of the surface profile and fully reflects the height characteristics of the surface's microscopic geometry.

[0066] In an embodiment of the present invention, the ratio between the roughness Rz and the arithmetic average roughness Ra of the two surfaces of the metal foil in the MD direction or the TD direction is further optimized. According to the definitions of roughness Rz and arithmetic average roughness Ra, roughness Rz represents the peak height of the surface profile, that is, the maximum height, while arithmetic average roughness Ra represents the average height level of the surface profile. By optimizing the ratio of the two roughnesses with different meanings, the ratio of the two is made to be within a preferred reasonable range, thereby controlling the overall roughness and morphological structure of the metal foil surface in the same direction, avoiding a situation where the roughness Rz and the arithmetic average roughness Ra of the metal foil surface differ too much, resulting in the metal foil surface being not flat and uniform. This further ensures the flatness and thickness uniformity of the two surfaces of the metal foil, makes it less prone to warping, effectively improves the overall quality of the metal foil product, and helps solve the problems of battery stability, safety, reliability, etc. using metal foil as the negative electrode material and the problem of transportation during the product production process.

[0067] As a preferred embodiment, the embodiment of the present invention is further implemented on the basis of any of the above embodiments, and the ratio of the arithmetic average roughness Ra (am) in the MD direction of the first surface to the arithmetic average roughness Ra (bm) in the MD direction of the second surface is The ratio of the arithmetic average roughness Ra (at) in the TD direction of the first surface to the arithmetic average roughness Ra (bt) in the TD direction of the second surface is between between.

[0068] In an embodiment of the present invention, the ratio of the arithmetic mean roughness Ra of the first surface A and the second surface B of the metal foil in the same direction (including the MD and TD directions) is further optimized. Furthermore, the arithmetic mean roughness Ra of the two surfaces of the metal foil is kept within a reasonable range, which further improves the uniformity of the surface structure and properties of the two surfaces, ensures the flatness and thickness uniformity of the two surfaces of the metal foil, and reduces the risk of warping and other problems. This effectively improves the overall quality of the metal foil product and ensures that the thickness fluctuation of the metal foil is within a low range. Batteries using this metal foil as the negative electrode material significantly improve the uniformity of the electrolyte and the negative electrode material active material on the surface of the metal foil product, improving the dimensional stability of the battery material and the balance and reliability of the electrochemical reaction process. This helps improve the electrochemical reaction efficiency, battery energy density, and battery quality. Furthermore, it reduces the problems of roller sticking and skewing during the application of active material and winding, thereby improving the conveying efficiency and product yield of the battery negative electrode material production process.

[0069] As a preferred embodiment, the thickness H of the metal foil is ≤ 12 μm.

[0070] More preferably, the thickness H of the metal foil satisfies 4.0 μm≤H≤8 μm.

[0071] In an embodiment of the present invention, the overall thickness of the metal foil is further optimized. The thickness H of the metal foil is less than or equal to 12 μm, preferably between 4 and 8 μm, and can be, for example, 4 μm, 4.2 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, 5 μm, 5.1 μm, 5.2 μm, 5.3 μm, 5.4 μm, 5.5 μm, 5.6 μm, 5.7 μm, 5.8 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, or 8 μm. Of course, the thickness of the metal foil can also be any other value between 4 and 8 μm, which will not be repeated here.

[0072] By adopting the technical means of the embodiments of the present invention, the structure of the metal foil is relatively thinner and lighter, and is neither too thin nor too thick, but falls within an optimal and reasonable range. When the metal foil is applied to new energy batteries, the total thickness of the metal foil is not too thin, thereby avoiding the situation where the metal foil is easily damaged or the negative electrode material is broken during the winding process during the battery preparation process. It is also not too thick, thereby avoiding the excessive weight and volume of the metal foil, which is conducive to reducing the weight of the battery. In a battery pack of a certain volume, the thinner the metal foil structure, the more metal foil material is wound, and the more electrolyte and negative electrode material active substances are coated on the surface, thereby effectively improving the energy density of the battery, and then effectively improving the battery's range.

[0073] As a preferred embodiment, the thickness of the support 1 is less than or equal to 10 μm. More preferably, the thickness of the support 1 is between 2.5 and 6 μm.

[0074] In the embodiment of the present invention, the thickness of the support in the metal foil is further optimized. The thickness of the support 1 is less than or equal to 10 μm, preferably between 2.5 and 6 μm, and can be, for example, 2.5 μm, 3 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 4 μm, 4.2 μm, 4.5 μm, 4.8 μm, 5 μm, 5.3 μm, 5.5 μm, 5.7 μm, or 6 μm. Of course, the thickness of the metal foil can also be any other value between 2.5 and 6 μm, which will not be repeated here.

[0075] The technical measures employed in the embodiments of the present invention ensure that the support is not too thin, ensuring that its thickness is sufficient to support the entire metal foil skeleton and facilitate the production and manufacturing of the metal foil. If the support is too thin, it can easily adhere to the surface of the conveyor roller during the installation of the conductive layer, leading to a large number of defects such as wrinkles and fine lines. At the same time, it is not too thick, preventing the metal foil from being excessively bulky and heavy. This is beneficial when the metal foil is used in the field of new energy batteries, as the overall weight and volume of the battery are not excessively large. Therefore, the preferred thickness of the support can reduce the occurrence of the above-mentioned problems, improve the yield of the metal foil product, and ensure sufficient strength performance.

[0076] As a preferred embodiment, see Figure 2 , is a schematic diagram of the structure of a second metal foil provided by an embodiment of the present invention. This embodiment of the present invention is further implemented based on any of the above embodiments. The metal foil includes a support 1 and a conductive layer 2, and further includes metal pad layers 3 located on both surfaces of the support 1, namely a first metal pad layer 31 and a second metal pad layer 32. The first metal pad layer 31 is located between the support 1 and the first conductive layer 21, and the second metal pad layer 32 is located between the support 1 and the second conductive layer 22.

[0077] In an embodiment of the present invention, by first arranging the metal paving layer 3 on both surfaces of the support 1 and then arranging the conductive layer 2, the formation of the conductive layer 2 is facilitated, the formation efficiency and density of the conductive layer 2, and the surface flatness of the conductive layer 2 are improved, and the generation of wrinkles and fine lines on the surface of the metal foil is helped to be reduced.

[0078] The material of the metal pad layer 3 specifically includes at least one metal such as copper, nickel, or an alloy formed by at least one of them; the formation process of the conductive layer 2 can be various methods such as electroplating, evaporation plating or vacuum sputtering, which are not limited here.

[0079] Preferably, after the first metal pad layer and the second metal pad layer are respectively provided on the two surfaces of the support 1, when no conductive layer is further provided on the two side surfaces, the elastic modulus of the metal pad layer (the first metal pad layer or the second metal pad layer) in the MD direction is greater than the elastic modulus of the metal pad layer in the TD direction. Furthermore, the ratio of the elastic modulus of the metal pad layer in the MD direction to the elastic modulus in the TD direction is This ratio is further preferably More preferably

[0080] Preferably, the roughness Rz of the metal pad layer is 0.6-2.5 μm.

[0081] By adopting the technical means of the embodiment of the present invention, the roughness and elastic modulus of the metal pad layer of the metal foil before the conductive layer is formed are optimized, thereby creating a reasonable structural foundation for the subsequent formation of the conductive layer. The presence of a certain roughness on the surface of the metal pad layer is conducive to the formation of the conductive layer, and can ensure the bonding force between the conductive layer and the surface of the metal pad layer, so that the conductive layer is firmly formed on its surface and is not easy to peel off or fall off, providing excellent surface performance and strength foundation for the next application in battery negative electrode materials as active materials attached to the surface of the current collector. At the same time, the optimization of the ratio of the elastic modulus in the MD direction and the TD direction of the metal pad layer can better adapt to the scenario where winding is required during the preparation of battery negative electrode materials, provide a favorable foundation for the strength requirements of the metal foil during winding, avoid the situation where it is easy to break during the winding process in the MD direction, make it not easy to break during the winding process and be able to resist excessive stretching, thereby ensuring product yield and quality.

[0082] As a preferred embodiment, the conductive layer 2 includes a single metal conductive layer and / or an alloy conductive layer; wherein the single metal conductive layer is made of any one of copper, aluminum, iron, zinc, titanium, cobalt, gold, silver, nickel, chromium, indium, gallium, tin, thallium, lead, bismuth, germanium, antimony, polonium, beryllium, magnesium, calcium, strontium, barium, radium, lanthanide metals, actinide metals and transition metals; the alloy conductive layer is made of any two or more of copper, aluminum, iron, zinc, titanium, cobalt, gold, silver, nickel, chromium, indium, gallium, tin, thallium, lead, bismuth, germanium, antimony, polonium, beryllium, magnesium, calcium, strontium, barium, radium, lanthanide metals, actinide metals and transition metals; and can also be made of a mixture of any two or more of the above metals and other materials.

[0083] Furthermore, the thickness of the first conductive layer and / or the second conductive layer is less than or equal to 1 μm, and the total thickness of the first conductive layer and the second conductive layer is less than or equal to 1.5 μm.

[0084] By adopting the technical means of the embodiments of the present invention, the material, single layer thickness and total thickness of the conductive layer are optimized, and the total thickness and weight of the metal foil are further reduced. When applied in the field of new energy batteries, it is beneficial to improve the energy density of the battery and reduce the weight of the battery.

[0085] As a preferred embodiment, the metal foil further includes an anti-oxidation layer 4 , which is located on at least one surface of the conductive layer 2 , preferably on the surface on the side away from the support 1 .

[0086] Specifically, in one embodiment, see Figure 3, is a schematic structural diagram of a third metal foil provided by an embodiment of the present invention. The metal foil comprises a first conductive layer 21, a support 1, and a second conductive layer 22 stacked in sequence, with an anti-oxidation layer 4 added to the outer surfaces of the first conductive layer 21 and the second conductive layer 22, respectively.

[0087] In another embodiment, see Figure 4 , which is a schematic diagram of the structure of a fourth metal foil provided by an embodiment of the present invention. The metal foil comprises a first conductive layer 21, a first metal pad layer 31, a support 1, a second metal pad layer 32, and a second conductive layer 22, stacked in sequence. Anti-oxidation layers 4 are additionally provided on the outer surfaces of the first conductive layer 21 and the second conductive layer 22.

[0088] Preferably, the thickness of the anti-oxidation layer 4 is 0.8% to 30% of the thickness of the conductive layer 2 .

[0089] More preferably, the thickness of the anti-oxidation layer 4 is 1.5% to 19% of the thickness of the conductive layer 2 .

[0090] The technical approach of the embodiments of the present invention effectively improves the antioxidant properties of the conductive layer by coating the conductive layer with an antioxidant layer. When used in new energy batteries, this effectively prevents oxidation reactions between the conductive layer's surface and active materials, as well as oxidation when the conductive layer's surface comes into contact with the electrolyte. This improves the lifespan of the metal foil and the stability of the battery. Furthermore, by optimizing the thickness of the antioxidant layer, the antioxidant properties of the conductive layer and the utilization rate of the battery material are effectively improved without excessively increasing the weight of the metal foil or the internal resistance of the battery reaction.

[0091] As a preferred embodiment, the metal foil further includes a bonding layer 5 .

[0092] In an alternative embodiment, see Figure 5 , is a schematic structural diagram of the fifth metal foil provided in an embodiment of the present invention. The metal foil includes a support 1, a conductive layer 2 and a bonding layer 5, and the bonding layer 5 is located on the surface of the conductive layer 2 on the side away from the support 1. As an example, when the metal foil is a three-layer structure in which a first conductive layer 21, a support 1 and a second conductive layer 22 are stacked in sequence, a bonding layer 5 is added to the outer surface of the first conductive layer 21, and a bonding layer 5 is added to the outer surface of the second conductive layer 22. And the adhesion amount of the bonding layer on the surface of the first conductive layer 21 and the second conductive layer 22 is less than or equal to 150 mg / m 2 .

[0093] In another alternative embodiment, see Figure 6, is a schematic structural diagram of the sixth metal foil provided by an embodiment of the present invention. The metal foil includes a support 1, a conductive layer 2, an anti-oxidation layer 3 and a bonding layer 5, and the bonding layer 5 is located on the surface of the anti-oxidation layer 3 on the side away from the conductive layer 2. For example, when the metal foil is a multilayer structure in which the anti-oxidation layer 3, the first conductive layer 21, the support 1, the second conductive layer 22 and the anti-oxidation layer 3 are stacked in sequence, a bonding layer 5 is added to the surface of the anti-oxidation layer 3 on both sides, that is, the anti-oxidation layer 3 is located between the conductive layer 2 and the bonding layer 5, and the adhesion amount of the bonding layer on the surface of the anti-oxidation layer is less than or equal to 150 mg / m 2 .

[0094] By adopting the technical means of the embodiments of the present invention, by designing the bonding layer and optimizing its adhesion amount, when applied in the field of new energy batteries, it is possible to ensure the maximum adhesion and bonding between the conductive layer surface of the metal foil and the negative active material of the battery, thereby preventing the negative active material from peeling off or falling off on the surface of the conductive layer. At the same time, it is possible to ensure that the adhesion amount of the bonding layer is within a reasonable range, thereby avoiding an excessive amount of bonding aid in the bonding layer that increases the weight and volume of the metal foil itself, thereby affecting the weight control and energy density improvement of the battery.

[0095] It should be noted that the bonding aid forming the bonding layer is specifically an organic bonding aid, or an inorganic aid, or a mixture of the two in a certain proportion, which can not only improve the adhesion between the active material and the metal foil, but also contain groups that can be cross-linked or chemically bonded with the negative electrode active material through its own chemical bonds, such as carboxyl groups, hydroxyl groups, etc. The specific type of bonding aid is not limited.

[0096] As a preferred embodiment, the adhesion amount of the bonding layer on the surface of the conductive layer or the anti-oxidation layer is less than or equal to 120 mg / m 2 , and greater than or equal to 26mg / m 2 .

[0097] By adopting the technical means of the embodiments of the present invention, the adhesion amount of the bonding layer is further optimized so that it is within a reasonable range, neither too large nor too small. This ensures the adhesion and bonding between the conductive layer and the negative electrode active material while avoiding an increase in the weight and volume of the metal foil itself, thereby ensuring that the battery has a light weight and a high energy density.

[0098] It is understandable that the metal foil may also include a support 1, a conductive layer 2, a metal pad layer 3, an anti-oxidation layer 4 and a bonding layer 5. In this case, the structural layer arrangement of the metal foil may refer to the above embodiment and will not be repeated here.

[0099] Ordinary metal foil was used as a control sample, and specific examples were used to test the surface wrinkles or stripes, the number of surface oxidation points, and the tensile strength of the ordinary metal foil and the metal foil with the structure of the embodiment of the present invention. Among them, S represents the metal foil with the structure of the embodiment of the present invention, including samples S1, S2, S3, S4, S5, S6 and S7; R represents ordinary metal foil, including control samples R1 and R2.

[0100] The test data of the arithmetic mean roughness Ra, root mean square roughness Rq and roughness Rz of the first surface A and the second surface B of the metal foil S of the embodiment of the present invention and the control metal foil R in the MD direction and TD direction are shown in Table 1: (Unit: μm)

[0101] Table 1

[0102]

[0103]

[0104] The comparison results of various performances are shown in Table 2:

[0105] Table 2

[0106]

[0107]

[0108] The surface wrinkles or streaks of the metal foil, as well as the number of surface oxidation points, are determined by observing, counting, and analyzing the first and second surfaces A and B of the metal foil. Elongation and tensile strength can be measured using an electronic universal testing machine by inputting parameters such as the thickness, length, and width of the metal foil into the testing software. To improve test accuracy, each data set is repeated at least 30 times, and the average of all results is calculated as the final test result. The metal foil test sample is greater than 150 mm in length and 10 mm in width.

[0109] From the comparison of Table 1 and Table 2, it can be seen that the metal foil product of the embodiment of the present invention is thinner, with fewer or even no obvious surface wrinkles or stripes, while ensuring strength performance, indicating that its surface is smoother, the surface roughness parameters on both sides are close, and the surface oxidation resistance is stronger. Moreover, when the thickness is equivalent, the metal foil product of the embodiment of the present invention has higher elongation and tensile strength, and various performances are better than those of the control samples R1 and R2.

[0110] An embodiment of the present invention further provides a negative electrode material for a battery, the negative electrode material comprising a negative electrode active material and the metal foil as described in any of the above embodiments, wherein the metal foil is tightly bonded to the negative electrode active material. Specifically, the bonding force between the active material and the surface of the metal foil is no less than the bonding force between the conductive layer and the support.

[0111] An embodiment of the present invention further provides a battery, wherein the negative electrode material of the battery is the negative electrode material applied to the battery as described above.

[0112] It should be noted that the structure of the metal foil may refer to the structure of the metal foil described in any of the above embodiments, and will not be described in detail here.

[0113] The technical means of the embodiments of the present invention and the use of the metal foil as the negative electrode carrier or current collector of the above battery have the following advantages: by controlling the morphology structure and production process of the first surface A and the second surface B, the roughness Rz, arithmetic mean roughness Ra and root mean square roughness Rq of the two outer surfaces of the metal foil in the MD direction and TD direction are optimized to be within a reasonable range, and the relationship between them is more reasonable. In addition, with the improvement of the thickness and structural composition of the metal foil, the structure and performance of the two surfaces in the MD direction and TD direction are more uniform and consistent. No wrinkles or fine stripes are generated during the production process, or the wrinkles and fine stripes generated are very small, and the resulting roughness fluctuation is significantly reduced, ensuring the flatness and thickness uniformity of the two surfaces of the metal foil, and not prone to warping and other problems. The quality of the metal foil product is effectively improved, which is conducive to the uniform spreading and adhesion of the metal foil and the negative electrode material active substance, improving the dimensional stability of the battery material and the balance and reliability of the electrochemical reaction process, and helping to improve the electrochemical reaction efficiency, improve the battery energy density, and effectively reduce the battery weight and thickness, thereby improving the battery safety.

[0114] As a preferred embodiment, the support in the metal foil is an insulating material.

[0115] Specifically, the insulating material can be any one of: polyethylene naphthalate (PEN), polyamide, polyethylene terephthalate (PET), polyimide (PI), polyterephthalate, polytetrafluoroethylene, polyethylene (PE), polyvinyl chloride, polystyrene, polypropylene (PP), acrylonitrile-butadiene-styrene copolymer, silicone rubber, polybutylene terephthalate, poly(p-phenylene terephthalamide), polypropylene, polyoxymethylene, epoxy resin, polycarbonate, phenolic resin, and polyvinylidene fluoride.

[0116] By adopting the technical means of the embodiment of the present invention and using insulating material as a support for the metal foil, short circuits in extreme conditions inside the battery, such as excessive heat inside the battery, can be effectively reduced, thereby improving the safety of the battery.

[0117] It should be noted that the battery provided in the embodiments of the present invention can be applied to various types of devices, including but not limited to portable electronic devices, electric vehicles, electric toys and electric tools. For example, portable electronic devices include mobile phones and laptops, electric vehicles include battery vehicles, electric vehicles, electric ships and spacecraft, electric toys include game consoles and electric car toys, and electric tools include electric drills, electric wrenches and electric screwdrivers, etc. Of course, it can also be applied to other devices according to actual conditions, which will not be elaborated here.

[0118] An embodiment of the present invention further provides a conductive material using the metal foil provided in any of the above embodiments. The structure of the metal foil can refer to the structure of the metal foil described in any of the above embodiments, and will not be described in detail here.

[0119] When used as other conductive materials, the metal foil support is a conductive material, the specific form of which is not limited. In one optional embodiment, a plurality of conductive particles can be dispersed within the support to provide conductivity. The conductive particles can be one or more metal ions selected from the material types listed above for the conductive layer. The metal particles have a particle size of 30 nm or less, preferably 15 nm or less.

[0120] In another optional manner, a conducting channel is opened in the support body, and a conducting material is arranged in the channel for conduction. The shape of the conducting channel can be square, circular, irregular, etc. The opening area of ​​the conducting channel accounts for 30% to 70% of the largest side surface area of ​​the support body. After the conducting channel is set, the weight ratio of the conducting material is more than 50% of that when the conducting channel is not opened, preferably 60% to 85%. The conducting material can also be divided into metal or non-metallic materials. When it is a metal material, it can be specifically selected from one or more of the material selection types of the conductive layer in the above embodiment. When the conducting material is non-metallic, it can be graphite, conductive carbon black, graphene, carbon nanotubes, carbon nanospheres / microparticles, etc. The conducting material is arranged inside the conducting channel, specifically on the inner wall, or filled in the conducting channel, which does not affect the beneficial effects of the present invention.

[0121] In another optional embodiment, the support body is configured to be a modified metallic conductive material or non-metallic conductive material with strong ductility and elastic modulus, and the non-metallic conductive material is, for example, conductive carbon black, graphite, graphene, CNT (carbon nanotube), etc.

[0122] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A metal foil, characterized in that The invention comprises at least one non-conductive support and conductive layers located on two surfaces of the support, namely a first conductive layer and a second conductive layer, wherein the surface of the first conductive layer away from the support is the first surface, and the surface of the second conductive layer away from the support is the second surface; the roughness Rz(at) of the first surface in the TD direction is equal to or greater than the roughness Rz(am) of the first surface in the MD direction; the roughness Rz(bt) of the second surface in the TD direction is equal to or greater than the roughness Rz(bm) of the second surface in the MD direction, so that the structures and properties of the first surface and the second surface are uniform and consistent, and surface wrinkles are reduced; The ratio of the roughness Rz(am) in the MD direction of the first surface to the roughness Rz(at) in the TD direction of the first surface is and / or, the ratio of the roughness Rz(bm) in the MD direction of the second surface to the roughness Rz(bt) in the TD direction of the second surface is between between; Furthermore, the ratio of the arithmetic mean roughness Ra (am) of the first surface in the MD direction to the arithmetic mean roughness Ra (bm) of the second surface in the MD direction is between and / or the ratio of the arithmetic average roughness Ra(at) in the TD direction of the first surface to the arithmetic average roughness Ra(bt) in the TD direction of the second surface is between between.

2. The metal foil according to claim 1, wherein The ratio of the root mean square roughness Rq(am) in the MD direction of the first surface to the root mean square roughness Rq(at) in the TD direction of the first surface is between; And / or, the ratio of the root mean square roughness Rq(bm) in the MD direction of the second surface to the root mean square roughness Rq(bt) in the TD direction of the second surface is in the range of between.

3. The metal foil according to claim 1 or 2, wherein The thickness H of the metal foil is ≤ 12 μm.

4. The metal foil according to claim 3, wherein The thickness of the support is less than or equal to 10 μm.

5. The metal foil according to claim 1 or 2, wherein The metal foil further includes metal pad layers located on both surfaces of the support, namely a first metal pad layer and a second metal pad layer. The first metal pad layer is located between the support and the first conductive layer, and the second metal pad layer is located between the support and the second conductive layer.

6. The metal foil according to claim 5, wherein The elastic modulus of the metal pad layer in the MD direction is greater than the elastic modulus of the metal pad layer in the TD direction, and the roughness Rz of the metal pad layer is between 0.6 and 2.5 μm.

7. The metal foil according to claim 1 or 2, wherein The material of the conductive layer includes at least one metal selected from the group consisting of copper, aluminum, iron, zinc, titanium, cobalt, gold, silver, nickel, chromium, indium, gallium, tin, thallium, lead, bismuth, germanium, antimony, polonium, beryllium, magnesium, calcium, strontium, barium, radium, lanthanide metals, and actinide metals, and / or an alloy formed from at least one of them.

8. The metal foil according to claim 1 or 2, wherein The metal foil further includes an anti-oxidation layer, which is located on at least one surface of the conductive layer, and has a thickness of 0.8% to 30% of the thickness of the conductive layer.

9. A negative electrode material for a battery, characterized in that: The negative electrode material includes a negative electrode active material and the metal foil according to any one of claims 1 to 8, and the metal foil is tightly bonded to the negative electrode active material.

10. The negative electrode material for battery according to claim 9, characterized in that: The support in the metal foil is an insulating material.

11. A battery, characterized in that: The negative electrode material of the battery is the negative electrode material for battery according to claim 9 or 10.

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