Bipolar current collector and battery

Abstract

The utility model aims to provide the bipolar current collector and the battery, the bipolar current collector adopts the design that the edge is provided with the blank area, so that the metal conductive area cannot be influenced in the slitting process, the problem of internal short circuit of the bipolar current collector is effectively improved, and the service life of the battery is prolonged. The method is of great significance to preparation of the bipolar current collector in the actual production process, and does not affect the workshop environment and the product quality.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a bipolar current collector and a battery. Background Art

[0002] In a bipolar battery, the positive and negative electrodes are respectively coated on both sides of the same current collector. The battery only needs the current collector for connection and sealing, which greatly reduces the introduction of inactive components. The bipolar current collector is slit after coating the electrode sheet; during the slitting process, the copper layer and the aluminum layer will be sheared, generating metal wires and metal powders, resulting in conduction between both sides of the bipolar current collector and causing an internal short circuit, reducing the battery life.

[0003] In view of this, it is of great practical significance to provide a new bipolar current collector structure to solve the problem of internal short circuit between the positive and negative electrodes caused during the slitting process after coating the electrode sheet. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a bipolar current collector and a battery. The bipolar current collector adopts a design with blank areas arranged at the edges, which can avoid affecting the metal conductive areas during the slitting process, effectively improving the problem of internal short circuit in the bipolar current collector, being of great significance for preparing the bipolar current collector in the actual production process, and not affecting the workshop environment and product quality.

[0005] According to the first aspect of the utility model, a bipolar current collector is provided, which sequentially includes a positive electrode metal layer, a polymer layer, and a negative electrode metal layer; the positive electrode metal layer and the negative electrode metal layer are respectively located on the first surface and the second surface opposite to each other of the polymer layer; the first surface has a first edge area, a positive electrode metal area, and a second edge area, and the positive electrode metal area is covered by the positive electrode metal layer; the second surface has a third edge area, a negative electrode metal area, and a fourth edge area, and the negative electrode metal area is covered by the negative electrode metal layer; the first edge area and the third edge area are arranged opposite to each other, and the second edge area and the fourth edge area are arranged opposite to each other; at least one of the first edge area and the third edge area is a blank area; at least one of the second edge area and the fourth edge area is a blank area.

[0006] In the bipolar current collector provided by the present utility model, a total of four edge regions are provided on both sides, and at least one of the two edge regions on each side is a blank region. In this way, during slitting, the generation of metal wires and metal powders can be greatly reduced, thus effectively avoiding the risk of short circuit between the positive and negative electrodes, reducing the risk of cell failure, improving the production efficiency and product quality while further increasing the service life of the battery module. In addition, during the slitting process, the generation of metal wires and metal powders is greatly reduced, which can also reduce the impact on the workshop environment, improve the workshop environment level, and prevent metal wires or metal powders from floating in the air and affecting the operation of the production line and the quality of the products.

[0007] Preferably, the first edge region, the second edge region, the third edge region, and the fourth edge region are all blank regions. When all four edge regions are blank regions, the amount of metal wires and metal powders generated during the slitting process can be further reduced, thereby further reducing the risk of short circuit between the positive and negative electrodes in the current collector, improving the product yield, and increasing the service life of the battery pack.

[0008] Preferably, when the first edge region or the third edge region is a first non-blank region, the first non-blank region is covered with the same metal as the positive electrode metal layer to form an edge positive electrode metal layer; and the thickness of the edge positive electrode metal layer is not greater than that of the positive electrode metal layer; and when the second edge region or the fourth edge region is a second non-blank region, the second non-blank region is covered with the same metal as the negative electrode metal layer to form an edge negative electrode metal layer; and the thickness of the edge negative electrode metal layer is not greater than that of the negative electrode metal layer. Setting the non-blank regions as the edge positive electrode metal layer and the edge negative electrode metal layer can ensure that no other impurities are incorporated after the bipolar current collector is slit, and the performance of the bipolar current collector is not affected. And ensuring that the thicknesses of the edge positive electrode metal layer and the edge negative electrode metal layer are not higher than those of the positive electrode metal layer and the negative electrode metal layer respectively can result in fewer metal wires or metal powders during slitting, avoiding the conduction and short circuit between the positive and negative electrodes of the bipolar current collector. Because if the thicknesses of the edge positive electrode metal layer and the edge negative electrode metal layer are too high, although the opposite side is a blank region, a large amount of metal wires or metal powders will be generated during slitting due to the too thick edge metal layer, increasing the risk of conduction and short circuit between the positive and negative electrodes of the bipolar current collector.

[0009] Preferably, when the first edge region or the third edge region is a first non-blank region, the first non-blank region is covered with the same metal as the positive electrode metal layer to form an edge positive electrode metal layer; and the thickness of the edge positive electrode metal layer is less than that of the positive electrode metal layer; and when the second edge region or the fourth edge region is a second non-blank region, the second non-blank region is covered with the same metal as the negative electrode metal layer to form an edge negative electrode metal layer; and the thickness of the edge negative electrode metal layer is less than that of the negative electrode metal layer.

[0010] Preferably, the thicknesses of the edge positive electrode metal layer and the edge positive electrode metal layer do not exceed 1 μm.

[0011] Preferably, the orthographic projection part of the first edge region on the polymer layer is the first edge polymer layer, and the orthographic projection part of the fourth edge region on the polymer layer is the second edge polymer layer; the thickness of the first edge polymer layer is greater than that of the polymer layer; and / or, the thickness of the second edge polymer layer is greater than that of the polymer layer. Making the thickness of the first edge polymer layer greater than that of the polymer layer (in the middle part), and making the thickness of the second edge polymer layer greater than that of the polymer layer, when slitting, on the one hand, it reduces the metal wires and metal powders generated by cutting the edge metal layer. On the other hand, even if a certain amount of metal wires and metal powders are generated during the cutting process, due to the relatively large thickness of the edge polymer layer in the middle, the contact spacing of the metal wires and metal powders generated by the positive and negative electrode metal layers is increased. Therefore, the risk of short circuit between the positive and negative electrodes in the current collector can be further reduced, the quality and production efficiency of the current collector product can be improved, and the life of the battery module can be improved.

[0012] Preferably, the sum of the thicknesses of the edge positive electrode metal layer and the first edge polymer layer or the second edge polymer layer is equal to the sum of the thicknesses of the positive electrode metal layer and the polymer layer; the sum of the thicknesses of the edge negative electrode metal layer and the first edge polymer layer or the second edge polymer layer is equal to the sum of the thicknesses of the negative electrode metal layer and the polymer layer. Making the sum of the thicknesses of each layer at the edge of the bipolar current collector consistent with the sum of the thicknesses of the corresponding layers in the middle can ensure that the cutting surface is flat during slitting, and at the same time reduce the structural defects caused by inconsistent thickness during cutting, which deteriorate the quality or performance of the current collector product.

[0013] Preferably, the width of the first edge region is 1 - 10 mm; the width of the second edge region is 1 - 10 mm; the width of the third edge region is 1 - 10 mm; the width of the fourth edge region is 1 - 10 mm. The widths of these edge regions cannot be too small. If they are too small, during slitting, processing errors may cause the cut edges to be misaligned, and there is a risk of cutting into the metal layer area in the middle part, which is likely to produce burrs and cause the risk of short circuit between the positive and negative metal layers; the widths of the edge regions cannot be too large. If they are too large, it will waste the internal space of the battery, reduce the space utilization rate, and the battery energy density will decrease.

[0014] Preferably, the positive electrode metal layer and the negative electrode metal layer are made of different metals.

[0015] Preferably, the thickness of the positive electrode metal layer is 0.5 - 4 μm; the thickness of the negative electrode metal layer is 0.5 - 4 μm; the thickness of the polymer layer is 3 - 10 μm.

[0016] Preferably, the method for forming the positive electrode metal layer includes at least one of the following methods: physical vapor deposition method; the method for forming the negative electrode metal layer includes at least one of the following methods: hydroplating method, magnetron sputtering method.

[0017] According to another aspect of the present invention, there is provided a battery including the above bipolar current collector. For the battery prepared by using the bipolar current collector provided by the present invention, since the risk of short circuit between the positive and negative electrodes inside the bipolar current collector is greatly reduced, the product quality of the bipolar current collector is improved, and thus the risk of cell failure is reduced, so the service life of the battery module is prolonged. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the bipolar current collector in Embodiment 1 of the present invention.

[0019] Figure 2 It is a schematic structural diagram of one of the bipolar current collectors in Embodiment 2 of the present invention.

[0020] Figure 3 It is a schematic structural diagram of one of the bipolar current collectors in Embodiment 2 of the present invention.

[0021] Figure 4 It is a schematic structural diagram of one of the bipolar current collectors in Embodiment 3 of the present invention.

[0022] Figure 5 It is a schematic structural diagram of one of the bipolar current collectors in Embodiment 3 of the present invention.

[0023] The following is the description of the corresponding reference numerals:

[0024] 1-1, positive electrode metal layer; 1-3, polymer layer; 1-2, negative electrode metal layer; 2-1, first edge region; 2-2, second edge region; 2-3, third edge region; 2-4, fourth edge region; 2-1-1, edge positive electrode metal layer; 2-4-1, edge negative electrode metal layer; 2-1-2, first edge polymer layer; 2-4-2, second edge polymer layer. Detailed Embodiments

[0025] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0026] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs. The terms used in the description of the present utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model.

[0028] Embodiment 1

[0029] Reference Figure 1 , which is a schematic diagram of one of the bipolar current collector structures provided by the present utility model. The bipolar current collector sequentially includes a positive electrode metal layer 1-1, a polymer layer 1-3, and a negative electrode metal layer 1-2. The positive electrode metal layer 1-1 is an aluminum layer, and the negative electrode metal layer 1-2 is a copper layer; the thickness of the positive electrode metal layer 1-1 is 0.5 - 4 μm, the thickness of the polymer layer 1-3 is 3 - 10 μm, and the thickness of the negative electrode metal layer 1-2 is 0.5 - 4 μm.

[0030] Moreover, on the first surface and the second surface of the polymer layer 1-3 that are oppositely arranged, first edge regions 2-1, second edge regions 2-2, third edge regions 2-3, and fourth edge regions 2-4 are respectively arranged at the edges. The widths of these four edge regions are 1 - 10 mm, and these four edge regions are all blank regions. When these four edge regions are all blank regions, when the bipolar current collector is slit, the amount of metal wires and metal powders generated during the slitting process can be significantly reduced, thereby further reducing the risk of short circuit between the positive and negative electrodes in the current collector, improving the product yield, and increasing the battery pack life.

[0031] Embodiment 2

[0032] Reference Figure 2 , which is a schematic diagram of one of the bipolar current collector structures provided by the present utility model. The bipolar current collector sequentially includes a positive electrode metal layer 1-1, a polymer layer 1-3, and a negative electrode metal layer 1-2. The positive electrode metal layer 1-1 is an aluminum layer, and the negative electrode metal layer 1-2 is a copper layer; the thickness of the positive electrode metal layer 1-1 is 0.5 - 4 μm, the thickness of the polymer layer 1-3 is 3 - 10 μm, and the thickness of the negative electrode metal layer 1-2 is 0.5 - 4 μm.

[0033] Moreover, on the first surface and the second surface which are oppositely arranged on the polymer layer 1-3, at the edge, the first edge region is covered by the edge positive electrode metal layer 2-1-1. The metal used in the edge positive electrode metal layer 2-1-1 is the same as that in the positive electrode metal layer 1-1, and the thickness is also the same as that of the positive electrode metal layer 1-1. At the same time, at the edge, the fourth edge region is covered by the edge negative electrode metal layer 2-4-1. The metal used in the edge negative electrode metal layer 2-4-1 is the same as that in the negative electrode metal layer 1-2, and the thickness is also the same as that of the negative electrode metal layer 1-2. In this way, in the two edge regions on both sides respectively, one of them is a blank region. When cutting, the generated metal wires and metal powders can be greatly reduced, so that the risk of short circuit between the positive and negative electrodes can be effectively avoided, the risk of cell failure can be reduced. While further improving the life of the battery module, the production efficiency and product quality can be improved. In addition, during the cutting process, the generated metal wires and metal powders are greatly reduced, which can also reduce the impact on the workshop environment, improve the workshop environment level, and prevent metal wires or metal powders from floating in the air, thus affecting the operation of the production line and the quality of the products.

[0034] The widths of the edge positive electrode metal layer 2-1-1, the second edge region 2-2, the third edge region 2-3, and the edge negative electrode metal layer 2-4-1 are 1-10 mm, and the second edge region 2-2 and the third edge region 2-3 are both blank regions.

[0035] It should be noted here that the thickness of the edge positive electrode metal layer 2-1-1 can be inconsistent with that of the positive electrode metal layer 1-1, and the thickness of the edge negative electrode metal layer 2-4-1 can also be inconsistent with that of the negative electrode metal layer 1-2. Refer to Figure 3 , the thickness of the edge positive electrode metal layer 2-1-1 is less than that of the positive electrode metal layer 1-1, and the thickness of the edge negative electrode metal layer 2-4-1 is less than that of the negative electrode metal layer 1-2.

[0036] Embodiment 3

[0037] Refer to Figure 4 , which is a schematic diagram of one of the bipolar current collectors provided by the present invention. The double-current collector sequentially includes a positive electrode metal layer 1-1, a polymer layer 1-3, and a negative electrode metal layer 1-2. The positive electrode metal layer 1-1 is an aluminum layer, and the negative electrode metal layer 1-2 is a copper layer. The thickness of the positive electrode metal layer 1-1 is 0.5-4 μm, the thickness of the polymer layer 1-3 is 3-10 μm, and the thickness of the negative electrode metal layer 1-2 is 0.5-4 μm.

[0038] Moreover, on the first surface and the second surface which are oppositely arranged on the polymer layer 1-3, at the edge, the first edge region is covered by the edge positive metal layer 2-1-1 and the first edge polymer layer 2-1-2. The metal used for the edge positive metal layer 2-1-1 is the same as that of the positive metal layer 1-1, and its thickness is less than that of the positive metal layer 1-1. The first edge polymer layer 2-1-2 is made of the same material as the polymer layer 1-3, and the sum of the thicknesses of the edge positive metal layer 2-1-1 and the first edge polymer layer 2-1-2 is equal to the thickness of the positive metal layer 1-1. At the same time, at the edge, the fourth edge region is covered by the edge negative metal layer 2-4-1 and the second edge polymer layer 2-4-2. The metal used for the edge negative metal layer 2-4-1 is the same as that of the negative metal layer 1-2, and its thickness is less than that of the negative metal layer 1-2. The second edge polymer layer 2-4-2 is made of the same material as the polymer layer 1-3, and the sum of the thicknesses of the edge negative metal layer 2-4-1 and the second edge polymer layer 2-4-2 is equal to the thickness of the negative metal layer 1-2. By making the sum of the thicknesses of each layer at the edge of the bipolar current collector equal to the sum of the thicknesses of the corresponding layers in the middle, it can ensure that the cutting surface remains flat during slitting, and at the same time reduce the generation of some structural defects during cutting due to inconsistent thickness, which may deteriorate the quality or performance of the current collector product.

[0039] The widths of the edge positive metal layer 2-1-1, the first edge polymer layer 2-1-2, the second edge region 2-2, the third edge region 2-3, the edge negative metal layer 2-4-1, and the second edge polymer layer 2-4-2 are 1 to 10 mm, and the second edge region 2-2 and the third edge region 2-3 are both blank regions.

[0040] It should be noted here that the sum of the thicknesses of the edge positive metal layer 2-1-1 and the first edge polymer layer 2-1-2 may not be the same as the thickness of the positive metal layer 1-1; and the sum of the thicknesses of the edge negative metal layer 2-4-1 and the second edge polymer layer 2-4-2 may also not be the same as the thickness of the negative metal layer 1-2. Refer to Figure 5 , the sum of the thicknesses of the edge positive metal layer 2-1-1 and the first edge polymer layer 2-1-2 is less than the thickness of the positive metal layer 1-1, and the sum of the thicknesses of the edge negative metal layer 2-4-1 and the second edge polymer layer 2-4-2 is less than the thickness of the negative metal layer 1-2. Only the inconsistent thickness may cause some structural defects during cutting due to the uneven cutting surface, deteriorating the quality or performance of the current collector product.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced, but these modifications or replacements are all within the protection scope of the present invention.

Claims

1. A bipolar current collector, characterized in that: It includes a positive electrode metal layer, a polymer layer, and a negative electrode metal layer in sequence; The positive electrode metal layer and the negative electrode metal layer are respectively located on a first surface and a second surface of the polymer layer that are opposite to each other; The first surface has a first edge region, a positive metal region, and a second edge region, and the positive metal region is covered by the positive metal layer; The second surface has a third edge region, a negative metal region, and a fourth edge region, and the negative metal region is covered by the negative metal layer; The first edge area is arranged opposite to the third edge area, and the second edge area is arranged opposite to the fourth edge area; at least one of the first edge area and the third edge area is a blank area; at least one of the second edge area and the fourth edge area is a blank area.

2. The bipolar current collector according to claim 1, wherein: The first edge area, the second edge area, the third edge area, and the fourth edge area are all blank areas.

3. The bipolar current collector according to any one of claims 1 to 2, characterized in that: When the first edge region or the third edge region is a first non-blank region, the first non-blank region is covered with the same metal as the positive metal layer to form an edge positive metal layer; and the thickness of the edge positive metal layer is not greater than that of the positive metal layer; And when the second edge area or the fourth edge area is a second non-blank area, the second non-blank area is covered with the same metal as the negative metal layer to form an edge negative metal layer; and the thickness of the edge negative metal layer is not greater than that of the negative metal layer.

4. The bipolar current collector according to claim 3, wherein: The thickness of the edge positive electrode metal layer and the edge positive electrode metal layer does not exceed 1 μm.

5. The bipolar current collector according to claim 3, wherein: The orthographic projection of the first edge region on the polymer layer is defined as the first edge polymer layer, and the orthographic projection of the fourth edge region on the polymer layer is defined as the second edge polymer layer; The thickness of the first edge polymer layer is greater than that of the polymer layer; and / or the thickness of the second edge polymer layer is greater than that of the polymer layer.

6. The bipolar current collector according to claim 5, wherein: The sum of the thicknesses of the edge positive electrode metal layer and the first edge polymer layer or the second edge polymer layer is equal to the sum of the thicknesses of the positive electrode metal layer and the polymer layer; The sum of the thicknesses of the edge negative electrode metal layer and the first edge polymer layer or the second edge polymer layer is equal to the sum of the thicknesses of the negative electrode metal layer and the polymer layer.

7. The bipolar current collector according to claim 1, wherein: The width of the first edge region is 1 to 10 mm; the width of the second edge region is 1 to 10 mm; the width of the third edge region is 1 to 10 mm; and the width of the fourth edge region is 1 to 10 mm.

8. The bipolar current collector according to claim 1, characterized in that: The positive electrode metal layer and the negative electrode metal layer are made of different metals.

9. The bipolar current collector according to claim 1, wherein: The thickness of the positive electrode metal layer is 0.5 to 4 μm; The thickness of the negative electrode metal layer is 0.5 to 4 μm; The thickness of the polymer layer is 3 to 10 μm.

10. A battery, characterized in that: The invention comprises the bipolar current collector according to any one of claims 1 to 9.

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