Composite current collector, composite pole piece and lithium battery

Abstract

The utility model discloses a composite current collector, which comprises an insulating layer, and an anode metal layer and a cathode metal layer which are compounded on two sides of the insulating layer, wherein the anode metal layer is provided with an anode tab extending to the outside of the insulating layer, the cathode metal layer is provided with a cathode tab extending to the outside of the insulating layer, and the anode tab and the cathode tab extend in opposite directions. The utility model also comprises a composite pole piece and a lithium battery. The anode metal layer and the cathode metal layer are directly compounded on the surface of the insulating layer, meanwhile, the anode metal layer is directly provided with the anode tab, the cathode metal layer is directly provided with the cathode tab, tab welding through a subsequent welding process is not needed any more, the process is simplified, the tab yield is increased, and the yield is greatly increased; in addition, the tabs are in the same layer with the anode metal layer and the cathode metal layer, so that the thickness is not increased, and the volume of the battery is favorably reduced.

Description

Technical Field

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

[0002] Lithium battery is a widely used product with many advantages such as long cycle life, low self-discharge, high energy density and environmental protection, and is in demand in various fields.

[0003] Conventional lithium batteries are composed of a positive electrode, a separator, a negative electrode and an electrolyte. The positive electrode, separator and negative electrode are arranged in sequence and then wound or stacked to form a bare cell. After the electrolyte, shell and circuit board are added, a battery is formed. However, this conventional battery structure has problems such as difficulty in increasing energy density and difficulty in further reducing volume.

[0004] The composite current collector is a new type of pole piece structure, which is formed through processes such as magnetron sputtering and evaporation technology. Its shortcomings are complex process, low output, and great instability in the welding of the pole ears. At the same time, it is difficult to further reduce the volume of the battery. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides a composite current collector, a composite pole piece and a lithium battery.

[0006] The utility model discloses a composite current collector, comprising: an insulating layer, and an anode metal layer and a cathode metal layer composited on both sides of the insulating layer; wherein the anode metal layer is provided with an anode pole ear extending to the outside of the insulating layer, and the cathode metal layer is provided with a cathode pole ear extending to the outside of the insulating layer, and the anode pole ear and the cathode pole ear extend in opposite directions.

[0007] According to one embodiment of the present invention, the calculation formula for the extension length L of the anode tab and / or the cathode tab is:

[0008] L = 2H + a;

[0009] Wherein, H is the pit depth; a is the tolerance, and a=±1.5mm.

[0010] According to an embodiment of the present invention, the insulating layer is made of a polymer insulating material.

[0011] According to an embodiment of the present invention, the insulating layer is selected from any one of polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene and polyimide.

[0012] According to one embodiment of the present invention, the thickness of the anode metal layer and / or the cathode metal layer is 2 μm-50 μm.

[0013] The utility model discloses a composite pole piece, the composite current collector, the anode active material layer and the cathode active material layer, the anode active material layer is coated on the side of the anode metal layer of the composite current collector away from the insulating layer, and the cathode active material layer is coated on the side of the cathode metal layer of the composite current collector away from the insulating layer.

[0014] According to one embodiment of the present invention, the coating thickness of the anode active material layer is greater than the coating thickness of the cathode active material layer.

[0015] According to one embodiment of the utility model, the coating thickness of the anode active material layer is 20 μm-150 μm; the coating thickness of the cathode active material layer (5) is 15 μm-145 μm.

[0016] According to one embodiment of the utility model, the anode active material layer is any one of soft carbon, hard carbon, artificial graphite and natural graphite; the cathode active material layer is any one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium-rich manganese base, lithium iron phosphate, lithium manganese oxide and lithium iron manganese phosphate.

[0017] The utility model discloses a lithium battery, the composite pole piece and a diaphragm arranged on one side of an anode metal layer or one side of a cathode metal layer.

[0018] The beneficial effect of the utility model is that an anode metal layer and a cathode metal layer are directly compounded on the surface of the insulating layer. At the same time, an anode tab is directly opened on the anode metal layer, and a cathode tab is directly opened on the cathode metal layer. There is no need to weld the tabs through a subsequent welding process, which not only simplifies the process and improves the tab yield rate, but also greatly increases the output. In addition, the tabs are in the same layer as the anode metal layer and the cathode metal layer, which will not cause an increase in thickness and is conducive to reducing the volume of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1 is a schematic side cross-sectional view of a composite current collector;

[0021] Figure 2 It is a schematic diagram of the front side of the composite current collector;

[0022] Figure 3 It is the later processing of the tab;

[0023] Figure 4 is a schematic side cross-sectional view of a composite pole piece;

[0024] Figure 5It is a front schematic diagram of the anode side of the composite pole piece;

[0025] Figure 6 It is a front schematic diagram of the cathode side of the composite pole piece;

[0026] Figure 7 Schematic diagram of the internal structure of a lithium battery;

[0027] Figure 8 This is a schematic diagram of the front view of a lithium battery.

[0028] Description of Reference Numerals

[0029] 1. Insulation layer;

[0030] 2. Anode metal layer; 21. Anode ear;

[0031] 3. Cathode metal layer; 31. Cathode ear;

[0032] 4. Anode active material layer;

[0033] 5. cathode active material layer;

[0034] 6. Diaphragm;

[0035] 7. Anode side;

[0036] 8. Cathode side. DETAILED DESCRIPTION

[0037] The following will disclose multiple embodiments of the present invention with drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and components will be depicted in a simple schematic manner in the drawings.

[0038] In addition, in the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present utility model. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0039] Embodiment 1

[0040] like Figure 1 , Figure 2 and Figure 3 As shown, Figure 1 is a schematic side cross-sectional view of a composite current collector; Figure 2 It is a schematic diagram of the front side of the composite current collector; Figure 3 The composite current collector of the present application includes an insulating layer 1, an anode metal layer 2 and a cathode metal layer 3. The insulating layer 1 has two opposite sides, one side of which is provided with an anode metal layer 2 and the other side of which is provided with a cathode metal layer 3. The anode metal layer 2 is provided with an anode tab 21, which extends to the outside of the insulating layer 1; the cathode metal layer 3 is provided with a cathode tab 31, which extends to the outside of the insulating layer 1; wherein the direction in which the anode tab 21 extends is opposite to the direction in which the cathode tab 31 extends.

[0041] In this embodiment, the length of the anode tab 21 and the cathode tab 31 is not too limited, and the extension length of the two can be adjusted accordingly according to the subsequent different forming processes; for example: if multiple anode tabs 21 and cathode tabs 31 need to be transferred to Tab and bent, the anode tab 21 and the cathode tab 31 need to meet the size requirements of at least twice the depth of the pit. At the same time, there will be a certain tolerance in the process, and a certain tolerance amount needs to be appropriately increased, that is, the length of the anode tab 21 is at least twice the depth of the pit plus the tolerance amount, thereby ensuring that the length of the tab meets the use requirements of welding and bending; specifically, the length of the anode tab 21 and / or the cathode tab 31 is set to L, the pit depth is H, the tolerance amount is a, and a=±1.5, then L=2H+a. Specifically, the thickness of the anode metal layer 2 and the cathode metal layer 3 is 2μm-50μm.

[0042] Furthermore, the anode metal layer 2 and the cathode metal layer 3 are independent layers, that is, the anode metal layer 2 is not plated on the surface of the insulating layer 1 using processes such as magnetron sputtering and evaporation technology, but the anode metal layer 2 and the cathode metal layer 3 are independent materials and are attached to the surface of the insulating layer 1 using existing composite processes.

[0043] In specific applications, the anode metal layer 2 is made of copper material, such as existing copper foil material. The cathode metal layer 3 is made of aluminum material, such as existing aluminum foil material. The insulating layer 1 is made of any one of polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene and polyimide.

[0044] The anode metal layer 2 and the cathode metal layer 3 are directly compounded on the surface of the insulating layer 1. At the same time, the anode metal layer 2 is directly provided with an anode tab 21, and the cathode metal layer 3 is directly provided with a cathode tab 31. There is no need to weld the tabs through a subsequent welding process, which not only simplifies the process and improves the tab yield rate, but also greatly increases the output. In addition, the tabs are in the same layer as the anode metal layer 2 and the cathode metal layer 3, which will not cause an increase in thickness and is beneficial to reducing the volume of the battery.

[0045] Embodiment 2

[0046] like Figure 4-Figure 6 As shown, Figure 4 is a schematic side cross-sectional view of a composite pole piece; Figure 5 It is a front schematic diagram of the anode side 7 in the composite pole piece; Figure 6 1 is a front view of the cathode side 8 of the composite electrode. The composite electrode in this embodiment is made of the composite current collector in the first embodiment, so the structure of the composite current collector in the first embodiment will be directly cited in the following description.

[0047] The composite pole piece includes a composite current collector, an anode active material layer 4 and a cathode active material layer 5. The anode active material layer 4 is located on the side of the anode metal layer 2 away from the insulating layer 1, thereby forming an anode side 7 of the composite pole piece; the cathode active material layer 5 is located on the side of the cathode metal layer 3 away from the insulating layer 1, thereby forming a cathode side 8 of the composite pole piece.

[0048] In specific applications, the anode active material layer 4 is made of any one of soft carbon, hard carbon, artificial graphite and natural graphite; the cathode active material layer 5 is made of any one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium-rich manganese base, lithium iron phosphate, lithium manganese oxide and lithium iron manganese phosphate.

[0049] Specifically, the coating thickness of the anode active material layer 4 is 20μm-150μm; the coating thickness of the cathode active material layer 5 is 15μm-145μm; when used specifically, it should be ensured that the coating thickness of the anode active material layer 4 is greater than the coating thickness of the cathode active material layer 5 to ensure A / Coverhang after subsequent winding.

[0050] Embodiment 3

[0051] like Figure 7 and Figure 8 As shown, Figure 7 Schematic diagram of the internal structure of a lithium battery; Figure 8 The lithium battery in this embodiment is made of the composite pole piece in the second embodiment, so the structure of the composite pole piece in the second embodiment will be directly cited in the following description.

[0052] The lithium battery comprises a composite pole piece and a diaphragm 6, wherein the diaphragm 6 is located on the anode side 7 or cathode side 8 of the composite pole piece, and then the composite pole piece and the diaphragm 6 are wound and formed. Compared with the traditional lithium battery structure, the lithium battery structure of this embodiment can save a layer of diaphragm 6, which not only reduces the material cost, but also reduces the volume of the lithium battery.

[0053] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A composite current collector, characterized in that: include: An insulating layer (1), and an anode metal layer (2) and a cathode metal layer (3) composited on both sides of the insulating layer (1); wherein the anode metal layer (2) is provided with an anode pole ear (21) extending to the outside of the insulating layer (1), and the cathode metal layer (3) is provided with a cathode pole ear (31) extending to the outside of the insulating layer (1), and the anode pole ear (21) and the cathode pole ear (31) extend in opposite directions.

2. The composite current collector according to claim 1, characterized in that: The calculation formula for the extension length L of the anode tab (21) and / or the cathode tab (31) is: L = 2H + a; Wherein, H is the pit depth; a is the tolerance, and a=±1.5mm.

3. The composite current collector according to claim 1, characterized in that: The insulating layer (1) is made of polymer insulating material.

4. The composite current collector according to claim 3, characterized in that: The insulating layer (1) is made of any one of polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene and polyimide.

5. The composite current collector according to any one of claims 1 to 4, characterized in that: The thickness of the anode metal layer (2) and / or the cathode metal layer (3) is 2 μm-50 μm.

6. A composite pole piece, characterized in that: include: The composite current collector, anode active material layer (4) and cathode active material layer (5) as described in any one of claims 1 to 5, wherein the anode active material layer (4) is coated on the side of the anode metal layer (2) of the composite current collector away from the insulating layer (1), and the cathode active material layer (5) is coated on the side of the cathode metal layer (3) of the composite current collector away from the insulating layer (1).

7. The composite pole piece according to claim 6, characterized in that: The coating thickness of the anode active material layer (4) is greater than the coating thickness of the cathode active material layer (5).

8. The composite pole piece according to claim 7, characterized in that: The coating thickness of the anode active material layer (4) is 20 μm-150 μm; the coating thickness of the cathode active material layer (5) is 15 μm-145 μm.

9. The composite pole piece according to claim 8, characterized in that: The anode active material layer (4) is any one of soft carbon, hard carbon, artificial graphite and natural graphite; the cathode active material layer (5) is any one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium-rich manganese base, lithium iron phosphate, lithium manganese oxide and lithium iron manganese phosphate.

10. A lithium battery, characterized in that: It comprises the composite pole piece as claimed in any one of claims 6 to 9, and a diaphragm (6) arranged on one side of the anode metal layer (2) or on one side of the cathode metal layer (3).

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