Pole piece and lithium ion battery

Abstract

The utility model discloses a pole piece and a lithium ion battery using the same. The pole piece comprises a current collector and a tab, a heat conduction layer is arranged in the current collector, and a tab welding area is arranged on the surface of the current collector; the tab is welded in the tab welding area; an extension part is integrally arranged at a position, corresponding to the tab welding area, in the current collector, and the extension part extends in the direction away from the tab welding area and is embedded into the heat conduction layer. By adopting the structure, the heat conduction layer can quickly transfer heat generated at the welding position of the tab and the current collector to the whole current collector, and the temperature of the tab and / or the tab welding area is prevented from being greatly increased, so that a diaphragm or protective glue near the welding position of the tab and the current collector can be prevented from shrinking; the probability of combustion caused by contact short circuit of the positive plate and the negative plate is greatly reduced; the extension part can enhance the structural strength of the tab welding area, so that the welding between the tab and the tab welding area is firmer.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an electrode and a lithium-ion battery using the electrode. Background Technology

[0002] As we all know, with social development and the continuous progress of science and technology, the entertainment attributes of mobile phones and other electronic products are becoming stronger and stronger, which puts forward higher requirements for the large capacity and high discharge rate performance of consumer batteries.

[0003] To evaluate the discharge performance of high-capacity batteries and reduce the safety risks associated with their actual use, the industry standard is to require them to meet high-temperature short-circuit performance requirements. During high-temperature short-circuit testing, a significant amount of heat is generated at the welding points between the tabs (the positive electrode is typically pure aluminum, and the negative electrode is pure nickel or nickel-plated copper) and the current collector. This causes a substantial increase in temperature at the welding points, leading to shrinkage of the separator or protective adhesive near the tab weld. In severe cases, this can cause a short circuit between the positive and negative electrodes, potentially resulting in combustion.

[0004] Therefore, there is an urgent need for a lithium-ion battery that can reduce the significant temperature rise at the welding point between the current collector and the electrode tab, thereby improving the performance of lithium-ion batteries in high-temperature external short circuits and enhancing the safety of consumer electronics. Utility Model Content

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an electrode sheet that can quickly conduct heat generated at the welding point between the electrode tab and the current collector to the entire current collector, helping to prevent a significant temperature rise at the welding point. This invention also proposes a lithium-ion battery using the aforementioned electrode sheet, improving the high-temperature external short-circuit performance of the lithium-ion battery and contributing to enhanced safety performance in consumer electronics products using the lithium-ion battery of this invention.

[0006] An electrode sheet according to an embodiment of the present invention includes: a current collector and an electrode tab, wherein a heat-conducting layer is disposed inside the current collector, and an electrode tab welding area is disposed on the surface of the current collector; the electrode tab is welded to the electrode tab welding area; wherein an extension portion is disposed inside the current collector at a position corresponding to the electrode tab welding area, the extension portion extends in a direction away from the electrode tab welding area and is embedded inside the heat-conducting layer, and the extension portion and the current collector are integrally structured.

[0007] An electrode sheet according to an embodiment of the present invention has at least the following beneficial effects: By providing a heat-conducting layer inside the current collector, and welding the tab to the tab welding area on the surface of the current collector, when a large amount of heat is generated at the welding point between the tab and the current collector, the heat-conducting layer inside the current collector can quickly transfer the heat generated at the welding point between the tab and the current collector to the entire current collector, avoiding heat accumulation at the welding point between the tab and the current collector, which would cause a significant increase in the temperature of the tab and / or the tab welding area. Therefore, it can prevent the diaphragm or protective adhesive near the welding point between the tab and the current collector from shrinking, greatly reducing the probability of short circuit between the positive and negative electrodes causing combustion. At the same time, an extension is provided inside the current collector at a position corresponding to the tab welding area. The extension and the current collector are an integral structure. By adopting the above structure, it helps to increase the thickness of the tab welding area and enhance the structural strength of the tab welding area, thereby making the welding between the tab and the tab welding area more secure, ensuring that the welding between the tab and the current collector is firm and reliable and not easy to loosen. In addition, it can also improve the conductivity between the tab and the current collector.

[0008] According to some embodiments of the present invention, the current collector includes a first metal layer, a second metal layer and the thermally conductive layer, wherein the first metal layer, the thermally conductive layer and the second metal layer are stacked sequentially.

[0009] According to some embodiments of the present invention, the electrode welding area is disposed on the outer surface of the first metal layer, the extension is disposed on the inner surface of the first metal layer, and the extension and the first metal layer are integrally formed.

[0010] According to some embodiments of the present invention, the electrode tab has an electrode tab welding portion, which is welded to the electrode tab welding area of ​​the current collector;

[0011] Projecting along the vertical direction, the projection of the tab welding part is located inside the projection of the extension part, or the projection of the tab welding part and the projection of the extension part coincide.

[0012] According to some embodiments of this utility model, the width of the extension is L1, and the width of the electrode welding part is L2, satisfying L1 > L2.

[0013] According to some embodiments of this utility model, the width of the extension is L1, and the width of the electrode welding part is L2, satisfying L1-L2>2mm.

[0014] According to some embodiments of this utility model, the thickness of the current collector is X, and the thickness of the heat-conducting layer is Y, satisfying Y≤0.5X.

[0015] According to some embodiments of this utility model, the thickness of the extension is Z, which satisfies Z≥0.5Y.

[0016] According to some embodiments of this utility model, the thermally conductive layer is a graphene layer, a basic copper carbonate layer, an ammonium chloride layer, or an ammonium nitrate layer.

[0017] A lithium-ion battery according to an embodiment of the present invention includes a lithium-ion battery body, wherein the lithium-ion battery body is configured with one of the aforementioned electrode sheets.

[0018] A lithium-ion battery according to an embodiment of the present invention has at least the following beneficial effects: By employing the aforementioned electrode, when the lithium-ion battery is in a high-temperature external short-circuit state, the large amount of heat generated at the welding point between the electrode tab and the current collector can be quickly transferred to the entire current collector through the heat-conducting layer. This prevents a large amount of heat from accumulating at the welding point between the electrode tab and the current collector, thus avoiding a significant increase in the temperature of the electrode tab and / or the welding area. Therefore, it can prevent the separator or protective adhesive near the welding point between the electrode tab and the current collector from shrinking, greatly reducing the probability of combustion caused by a short circuit between the positive and negative electrode plates. This invention significantly improves the performance of lithium-ion batteries in high-temperature external short circuits, which helps to enhance the safety performance of consumer electronic products using lithium-ion batteries of this invention. Furthermore, an extension is provided inside the current collector corresponding to the tab welding area. The extension and the current collector are integrally structured. This structure helps to increase the thickness of the tab welding area, enhancing its structural strength and making the welding between the tab and the current collector more robust. This ensures a strong and reliable weld between the tab and the current collector, preventing it from easily loosening. Additionally, it improves the conductivity between the tab and the current collector.

[0019] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0021] Figure 1 This is a schematic diagram of the external structure of the electrode sheet according to a certain embodiment of the present invention;

[0022] Figure 2 for Figure 1 The cross-sectional view of the electrode shown in the figure;

[0023] Figure 3 for Figure 1 The figure shows an exploded cross-sectional view of the electrode tab and the first metal layer in the electrode sheet;

[0024] Figure 4 for Figure 1 The diagram shows a cross-sectional view of the mating structure of the first metal layer and the heat-conducting layer in the electrode.

[0025] Reference numerals: current collector 100, first metal layer 101, second metal layer 102, heat-conducting layer 110, electrode welding area 120, extension 130, electrode 200, electrode welding part 210. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0027] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0029] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0030] Reference Figures 1 to 4This invention discloses an electrode sheet (sometimes referred to as an electrode sheet in the following embodiments). The electrode sheet includes a current collector 100 and a tab 200. In this embodiment, the current collector 100 is generally flat. A heat-conducting layer 110 is disposed inside the current collector 100, arranged along the inner surface of the current collector 100. A tab welding area 120 is disposed on the surface of the current collector 100, and the tab 200 is welded to the tab welding area 120. In this embodiment, the area where the tab 200 contacts the surface of the current collector 100 is the tab welding area 120. An extension portion 130 is disposed inside the current collector 100 at a position corresponding to the tab welding area 120. The extension portion 130 extends away from the tab welding area 120 and is embedded inside the heat-conducting layer 110. The extension portion 130 and the current collector 100 are an integral structure.

[0031] By adopting the above structure, a heat-conducting layer 110 is provided inside the current collector 100, extending along the inner surface of the current collector 100. The heat-conducting layer 110 is made of a material with good thermal conductivity. The tab 200 is welded to the tab welding area 120 on the surface of the current collector 100. When the electrode in this embodiment is short-circuited, a large amount of heat is generated at the tab welding area 120 where the tab 200 and the current collector 100 are welded. The heat is transferred from the tab welding area 120 to the heat-conducting layer 110, and then the heat-conducting layer 110 quickly transfers the heat to various locations of the current collector 100, so that the heat can be quickly transferred to the entire current collector 100, avoiding a large amount of heat accumulation at the tab welding area 120 where the tab 200 and the current collector 100 are welded, which would cause the tab welding to fail. The temperature at the junction area 120 and / or the temperature of the tab 200 increases significantly, thus preventing the diaphragm or protective adhesive near the tab welding area 120 where the tab 200 is welded to the current collector 100 from shrinking. This greatly reduces the probability of short circuits between the positive and negative electrodes, which could lead to combustion. In addition, an extension 130 is provided inside the current collector 100 at a position corresponding to the tab welding area 120. The extension 130 and the current collector 100 are an integral structure. By adopting the above structure, the thickness of the tab welding area 120 is increased, enhancing the structural strength of the tab welding area 120. This makes the weld between the tab 200 and the tab welding area 120 more secure, ensuring that the weld between the tab 200 and the current collector 100 is firm, reliable, and not easily loosened.

[0032] Reference Figure 2 and Figure 4To enable the heat-conducting layer 110 to better transfer heat to the entire collector 100, in some embodiments of this invention, the heat-conducting layer 110 is disposed inside the collector 100, extending outward along the inner surface of the collector 100, and reaching the ends of each end face of the collector 100. That is, when projected vertically, the projection of the heat-conducting layer 110 coincides with the projection of the collector 100. By adopting the above structure, the heat-conducting layer 110 can effectively transfer heat to the entire collector 100, resulting in better heat conduction.

[0033] Reference Figure 2 , Figure 3 and Figure 4 To facilitate the production and processing of the electrode sheet in this embodiment, in some embodiments of this utility model, the current collector 100 includes a first metal layer 101, a second metal layer 102, and a thermally conductive layer 110, which are sequentially stacked. By adopting the above structure, the first metal layer 101, the second metal layer 102, and the thermally conductive layer 110 can be fabricated separately, and then the first metal layer 101, the thermally conductive layer 110, and the second metal layer 102 can be sequentially stacked to obtain the current collector 100 of this embodiment. Then, the tab 200 can be correspondingly welded to the tab welding area 120, greatly simplifying the electrode sheet manufacturing process and making the electrode sheet manufacturing of this embodiment simpler and more convenient, thus helping to reduce the production cost of the electrode sheet.

[0034] It should be noted that in the above embodiments, the first metal layer 101 and the second metal layer 102 are made of the same metal material. However, in other embodiments of this utility model, the first metal layer 101 and the second metal layer 102 can be made of different metal materials. For example, the first metal layer 101 can be a copper metal layer made of copper, while the second metal layer 102 can be an aluminum metal layer made of aluminum. The first metal layer 101 and the second metal layer 102 can be made of different metal materials according to actual needs, without limiting the first metal layer 101 to a copper metal layer or the second metal layer 102 to an aluminum metal layer.

[0035] In some embodiments of this invention, the tab welding area 120 is disposed on the outer surface of the first metal layer 101, and the extension 130 is disposed on the inner surface of the first metal layer 101, with the extension 130 and the first metal layer 101 forming an integral structure. In this embodiment, the outer surface of the first metal layer 101 refers to the surface of the first metal layer 101 away from the heat-conducting layer 110, while the inner surface of the first metal layer 101 refers to the surface of the first metal layer 101 in contact with the heat-conducting layer 110. By adopting the above structure, the first metal layer 101 and the extension 130 can be integrally formed, thereby making the first metal layer 101 and the extension 130 form an inseparable whole, which is convenient for manufacturing and processing, helps to reduce production costs, and facilitates the alignment of the tab welding area 120 and the extension 130. After the first metal layer 101 and the extension 130 are obtained by integral molding, the first metal layer 101, the heat-conducting layer 110 and the second metal layer 102 can be stacked in sequence to form a current collector 100. Then, the tab 200 can be welded to the tab welding area 120 on the upper surface of the first metal layer 101. The operation is simple and convenient.

[0036] It should be noted that in the above embodiment, the tab welding area 120 is disposed on the outer surface of the first metal layer 101, and the extension 130 is disposed on the inner surface of the first metal layer 101. In other embodiments of this utility model, the tab welding area 120 is disposed on the outer surface of the second metal layer 102, and the extension 130 is disposed on the inner surface of the second metal layer 102, and the extension 130 and the second metal layer 102 are integrally formed. The outer surface of the second metal layer 102 refers to the surface of the second metal layer 102 away from the heat-conducting layer 110, and the inner surface of the second metal layer 102 refers to the surface of the second metal layer 102 in contact with the heat-conducting layer 110. By adopting the above structure, the second metal layer 102 and the extension 130 can be integrally formed, and then the first metal layer 101, the heat-conducting layer 110 and the second metal layer 102 can be sequentially stacked to form the current collector 100. Then, the tab 200 can be correspondingly welded to the tab welding area 120 on the surface of the second metal layer 102, which is simple and convenient to operate.

[0037] Reference Figures 1 to 4In some embodiments of this invention, the tab 200 has a tab welding portion 210 for welding with the current collector 100. The tab welding portion 210 is welded to the tab welding area 120 of the current collector 100. Projected along the vertical direction, the projection of the tab welding portion 210 is located inside the projection of the extension 130, or the projection of the tab welding portion 210 and the projection of the extension 130 coincide. By adopting the above structure, the tab welding portion 210 can be welded to the area where the current collector 100 and the extension 130 coincide. The extension 130 can enhance the structural strength of the welding position between the tab welding portion 210 and the current collector 100, ensuring a firm and reliable connection between the tab 200 and the current collector 100. At the same time, it ensures good conductivity between the tab 200 and the current collector 100, so that the conductivity of the electrode can well meet the user's needs.

[0038] To ensure that the welding position between the tab 200 and the current collector 100 is better located within the overlapping area of ​​the extension 130 and the current collector 100, in some embodiments of this invention, the width of the extension 130 is L1, and the width of the tab welding portion 210 is L2, satisfying L1 > L2. Further, the width of the extension 130 is L1, and the width of the tab welding portion 210 is L2, satisfying L1 - L2 > 2mm. Specifically, when the width L2 of the tab welding portion 210 is 7mm, the width L1 of the extension 130 is > 9mm; when the width L2 of the tab welding portion 210 is 6mm, the width L1 of the extension 130 is > 8mm; and when the width L2 of the tab welding portion 210 is 5mm, the width L1 of the extension 130 is > 7mm. By adopting the above structure, when the tab 200 is welded to the current collector 100, the welding position of the tab 200 and the current collector 100 can be accurately located in the area where the extension 130 overlaps with the current collector 100.

[0039] To ensure good electrical conductivity of the current collector 100, in some embodiments of this invention, the thickness of the current collector 100 is X, and the thickness of the thermally conductive layer 110 is Y, satisfying Y ≤ 0.5X. Specifically, when the thickness X of the current collector 100 is 12 μm, the thickness Y of the thermally conductive layer 110 is ≤ 6 μm; when the thickness X of the current collector 100 is 10 μm, the thickness Y of the thermally conductive layer 110 is ≤ 5 μm; and when the thickness X of the current collector 100 is 8 μm, the thickness Y of the thermally conductive layer 110 is ≤ 4 μm. By adopting the above structure, the thermally conductive layer 110 has sufficient thermal conductivity, enabling it to quickly transfer the heat generated at the welding point between the tab 200 and the current collector 100 to the entire current collector 100, while simultaneously ensuring sufficient electrical conductivity to meet user requirements.

[0040] Furthermore, to ensure structural strength at the point where the extension 130 overlaps with the current collector 100, in some embodiments of this invention, the thickness of the thermally conductive layer 110 is Y, and the thickness of the extension 130 is Z, satisfying Z ≥ 0.5Y. Specifically, when the thickness Y of the thermally conductive layer 110 is 6 μm, the thickness Z of the extension 130 is ≥ 3 μm; when the thickness Y of the thermally conductive layer 110 is 5 μm, the thickness Z of the extension 130 is ≥ 2.5 μm; and when the thickness Y of the thermally conductive layer 110 is 4 μm, the thickness Z of the extension 130 is ≥ 2 μm. By adopting the above structure, the point where the extension 130 overlaps with the current collector 100 has sufficient thickness, thereby ensuring sufficient strength at the point where the current collector 100 is welded to the tab 200, guaranteeing a firm and reliable weld between the current collector 100 and the tab 200.

[0041] To ensure good thermal conductivity of the heat-conducting layer 110, in some embodiments of this invention, the heat-conducting layer 110 is a graphene layer, a basic copper carbonate layer, an ammonium chloride layer, or an ammonium nitrate layer; that is, the heat-conducting layer 110 is made of graphene, basic copper carbonate, ammonium chloride, or ammonium nitrate. Alternatively, the heat-conducting layer 110 can be composed of one or more composites of graphene, basic copper carbonate, ammonium chloride, and ammonium nitrate. By adopting the above structure, the heat-conducting layer 110 can achieve good thermal conductivity.

[0042] Reference Figures 1 to 4This utility model discloses a lithium-ion battery according to certain embodiments, including a lithium-ion battery body with an electrode sheet as described above. By employing the electrode sheet described above, when the lithium-ion battery is in a high-temperature external short-circuit state, the large amount of heat generated at the welding point between the tab 200 and the current collector 100 can be quickly transferred to the entire current collector 100 through the heat-conducting layer 110. This prevents a large amount of heat from accumulating at the welding point between the tab 200 and the current collector 100, thus avoiding a significant increase in the temperature of the tab 200 and / or the tab welding area 120. Therefore, it can prevent the separator or protective adhesive near the welding point between the tab 200 and the current collector 100 from shrinking, greatly reducing the probability of combustion caused by a short circuit between the positive and negative electrodes, and significantly improving the protection against high-temperature external short circuits in lithium-ion batteries. The improved performance helps enhance the safety of consumer electronics products using the lithium-ion battery of this invention. Furthermore, an extension 130 is provided inside the current collector 100 at a position corresponding to the tab welding area 120. The extension 130 and the current collector 100 are integrally formed. This structure helps increase the thickness of the tab welding area 120, strengthening its structural strength and resulting in a more robust weld between the tab 200 and the tab welding area 120. This ensures a strong and reliable weld between the tab 200 and the current collector 100, preventing it from easily loosening. Additionally, it improves the conductivity between the tab 200 and the current collector 100.

[0043] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The present invention has been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the invention.

Claims

1. An electrode sheet, characterized in that, include: A current collector (100) is provided with a heat-conducting layer (110) inside the current collector (100) and a tab welding area (120) is provided on the surface of the current collector (100); A tab (200) is welded to the tab welding area (120); The current collector (100) has an extension (130) located inside the current collector (100) at a position corresponding to the electrode welding area (120). The extension (130) extends away from the electrode welding area (120) and is embedded inside the heat-conducting layer (110). The extension (130) and the current collector (100) are an integral structure.

2. The electrode sheet according to claim 1, characterized in that, The current collector (100) includes a first metal layer (101), a second metal layer (102) and a heat-conducting layer (110), wherein the first metal layer (101), the heat-conducting layer (110) and the second metal layer (102) are stacked sequentially.

3. The electrode sheet according to claim 2, characterized in that, The electrode welding area (120) is disposed on the outer surface of the first metal layer (101), the extension (130) is disposed on the inner surface of the first metal layer (101), and the extension (130) and the first metal layer (101) are integrally formed.

4. An electrode sheet according to claim 1, characterized in that, The electrode tab (200) has an electrode tab welding portion (210), which is welded to the electrode tab welding area (120) of the current collector (100); Projecting along the vertical direction, the projection of the tab welding part (210) is located inside the projection of the extension part (130), or the projection of the tab welding part (210) and the projection of the extension part (130) coincide.

5. An electrode sheet according to claim 4, characterized in that, The width of the extension (130) is L1, and the width of the electrode welding part (210) is L2, satisfying L1 > L2.

6. An electrode sheet according to claim 5, characterized in that, The width of the extension (130) is L1, and the width of the electrode welding part (210) is L2, satisfying L1-L2>2mm.

7. An electrode sheet according to claim 1, characterized in that, The thickness of the current collector (100) is X, and the thickness of the heat-conducting layer (110) is Y, satisfying Y≤0.5X.

8. An electrode sheet according to claim 7, characterized in that, The thickness of the extension (130) is Z, which satisfies Z≥0.5Y.

9. An electrode sheet according to claim 1, characterized in that, The thermally conductive layer (110) is a graphene layer, a basic copper carbonate layer, an ammonium chloride layer, or an ammonium nitrate layer.

10. A lithium-ion battery, characterized in that, It includes a lithium-ion battery body, wherein the lithium-ion battery body is configured with an electrode as described in any one of claims 1 to 9.

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