Current collector plate, battery cell and battery

Abstract

Current collector plate, wherein the current collector plate comprises a current collector plate body (1) and a surface aluminium layer (2), wherein the current collector plate body (1) is made of copper and the surface aluminium layer (2) encloses an outer surface of the current collector plate body (1).

Description

Technical field

[0001] The present application relates to the technical field of battery technology and in particular to a current collector plate, a battery cell and a battery. background

[0002] The current collector plate is a component of the battery cell and is commonly used in various battery types, such as lithium-ion batteries. In the relevant technology, the current collector plate is typically welded to the exposed tabs of the winding core using a laser welding process. Generally, current collector plates are divided into positive and negative collector plates. Disclosure of registration

[0003] In related technologies, the base material of the current collector plate is aluminum. However, an aluminum-based current collector plate has a relatively high electrical resistance, resulting in a higher internal resistance of the battery cell. This significantly increases the internal heat generation of the battery cell. Some current collector plates are made of other materials with lower internal resistance. However, these current collector plates tend to corrode on their surface due to the electrolyte, leading to performance defects.

[0004] This application relates to a current collector plate. The current collector plate comprises a current collector plate body and a surface aluminum layer. The current collector plate body is made of copper, and the surface aluminum layer encases the outer surface of the current collector plate body.

[0005] This application also relates to a battery cell. The battery cell comprises the current collector plate described above.

[0006] This application also concerns a battery. The battery comprises the battery cell described above. Beneficial effects

[0007] The current collector plate, battery cell, and battery provided in this application are distinguished by the fact that the current collector plate body is made of copper instead of the aluminum used in conventional current collector plates. This reduces the internal resistance of the current collector plate during operation, which significantly reduces the likelihood of heat generation. Furthermore, a surface aluminum layer is applied to the outside of the copper current collector plate body. When welding the current collector plate body as part of the battery cell, the high temperature generated by the welding process can be used to initiate a chemical reaction between the surface aluminum layer and the oxygen in the air. This results in the formation of a dense oxide film coating in the welded area of ​​the current collector plate body.This dense oxide film coating exhibits good corrosion resistance and does not readily react with the electrolyte. Thus, during the battery cell's production and operation, direct contact between the electrolyte and the current collector plate occurs at the weld point of the current collector plate. This prevents the electrolyte from directly corroding the weld joint of the current collector plate, thereby mitigating corrosion of the weld area caused by contact between the current collector plate surface and the electrolyte. Description of the drawings Fig. Figure 1 is a schematic sectional view of the current collector plate according to some embodiments of the present application; Fig. 2 is a schematic structural representation of the current collector plate according to some embodiments of the present application; Fig. Figure 3 is a schematic cross-sectional view of the current collector plate made of Fig. 2; Fig. 4 is a schematic structural representation of the battery cell according to some embodiments of the present application; Fig. 5 is a schematic structural representation of section A from Fig. 4. Reference symbol:

[0008] 1, Current collector plate body; 11, Liquid inlet opening; 2, Surface aluminum layer; 5, Winding core; 7, Dense oxide film coating. Implementations of the application

[0009] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or suggesting a relative importance or the number of technical features specified. Accordingly, a feature designated as "first" or "second" may expressly or implicitly comprise one or more features. In the description of this application, "several" means two or more, unless expressly stated otherwise.

[0010] A current collector plate is a component that serves to collect the electrical energy of the battery cell in order to transfer it to a powered device, or to transfer the electrical energy to the battery cell during the charging process. The current collector plate is usually connected to the winding core, thus forming a battery cell.

[0011] The current collector plate is typically connected to the tabs of the winding core. The connection method is usually welding, with laser welding frequently used in the relevant technology to ensure weld strength and efficiency.

[0012] In the relevant technology, however, the base material of the current collector plate is aluminum. When aluminum is used as the base material of the current collector plate, the internal resistance of the battery cell is too high, leading to significant internal heat generation within the battery cell. This not only causes energy loss but can also lead to abnormal overheating, damaging the battery cell and ultimately causing battery failure. Although other materials with low internal resistance can be used to manufacture the current collector plate in the relevant technology, the surfaces of current collector plates made from most of these materials tend to corrode easily with the electrolyte.

[0013] First aspect, with reference to Fig. 1 shows Fig. Figure 1 shows a schematic cross-sectional structure diagram of the current collector plate provided in the present application. The present application provides a current collector plate comprising a current collector plate body 1 and a surface aluminum layer 2. The current collector plate body 1 is made of copper, and the surface aluminum layer 2 covers the outer surface of the current collector plate body 1.

[0014] It is understood that the way in which the surface aluminium layer 2 envelops the outside of the current collector plate body 1 can be achieved both by adhesion and by a fixed connection.

[0015] It is understandable that the current collector plate in the relevant technology consists of an aluminum plate, and its surface is typically not coated with a composite layer structure. While the aluminum construction makes the current collector plate economical, it also results in high internal resistance. When the current collector plate is in operation, this high internal resistance can cause heat to be generated during the input and output of electrical energy. This leads to energy loss and poses a risk of damaging components near the current collector plate, thus shortening the battery cell's lifespan.

[0016] In the present application, the material of the current collector plate body is changed from the conventionally used aluminum to copper, thereby reducing the internal resistance of the current collector plate during operation. This leads to a significant reduction in the likelihood of heat generation from the current collector plate during operation. A surface layer of aluminum is applied to the outer side surface of the copper current collector plate body. This surface layer allows the aluminum layer to chemically react with oxygen in the air due to the high temperatures generated during the welding of the current collector plate as part of the battery cell. This reaction forms a dense oxide film coating in the weld zone of the current collector plate. This dense oxide film coating exhibits good corrosion resistance and reacts only minimally with the electrolyte.This ensures that during the manufacturing and operation of the battery cell, the current collector plate inside the battery cell is not directly exposed to the electrolyte. Instead, the electrolyte comes into direct contact with the dense oxide film coating in the weld zone. This prevents the electrolyte from directly corroding the weld zone of the current collector plate, thus reducing corrosion of the weld zone caused by contact between the surface of the current collector plate and the electrolyte.

[0017] In some embodiments of the present application, see Fig. 2 and Fig. 3, shows Fig. 2 a schematic representation of the structure of the current collector plate provided in this application, and Fig. Figure 3 shows a schematic cross-sectional view of the current collector plate made of Fig. 2. As an example, the current collector plate is a positive current collector plate. A liquid inlet opening is provided on the surface of the current collector plate body, through which electrolyte can be injected into the interior of the battery cell housing. The surface aluminum layer also covers the wall surface of the liquid inlet opening.

[0018] It is understandable that in the battery cell production process, the current collector plate body 1 is coated with an aluminum layer by electroplating or chemical coating. Subsequently, the coated current collector plate body 1 is oxidized under the high temperature generated during the welding process with the winding core, resulting in the formation of a dense oxide film 7 on the coating. It is then assembled with the battery cell housing. After assembly, an electrolyte must be introduced into the battery cell through the liquid inlet opening 11, which is located on the surface of the positive current collector plate. During the introduction of the electrolyte, it inevitably comes into contact with the liquid inlet opening 11.

[0019] It is understandable that the current collector plate can generally be divided into a positive current collector plate and a negative current collector plate. The surface of the positive current collector plate is usually provided with a liquid inlet opening 11, which serves for filling the battery cell with electrolyte. In general, the electrolyte tends to corrode the liquid inlet opening 11 during the filling process. In the present application, if the current collector plate is a positive current collector plate, the liquid inlet opening 11 is also coated on its wall with a surface aluminum layer 2. Under the high temperature generated during the welding process, a dense oxide film coating 7 forms on the surface of the surface aluminum layer 2.This allows the wall of the liquid inlet opening 11 to develop resistance to corrosion by the electrolyte during the filling process.

[0020] It should be noted that under normal temperature conditions, the surface of the aluminum layer 2 reacts with oxygen to form a thin, dense oxide film 7. However, at high temperatures, it reacts rapidly with oxygen, resulting in a thicker, denser oxide film 7. The high temperature generated by welding can meet these high-temperature requirements, causing at least a portion of the surface of the aluminum layer 2 to react rapidly with oxygen and form a dense oxide film 7.

[0021] In some embodiments of this application, the surface aluminium layer 2 is a coating.

[0022] It is understandable that the bonding method between the surface aluminum layer 2 and the current collector plate body 1 can be achieved by extrusion, in which the surface aluminum layer 2 is extruded onto the current collector plate body 1 to form a composite structure. Alternatively, the surface aluminum layer 2 can be applied to the current collector plate body 1 by electroplating or chemical coating, resulting in a coating structure. Another possibility is to deposit the surface aluminum layer 2 onto the current collector plate body 1 by thin-film deposition, resulting in a thin-film deposition structure. Among these methods, the coating structure formed on the current collector plate body 1 by electroplating or chemical coating has a more uniform thickness compared to the composite structure formed by extrusion.In comparison to the thin-film deposition structure formed by thin-film deposition, this method is also more economical and practical.

[0023] For example, the surface aluminum layer 2 can be a chemical coating.

[0024] It is understandable that a coating is present on the surface of the current collector plate body 1. Typically, the surface aluminum layer 2 can be formed by electroplating. Alternatively, the surface aluminum layer 2 can be formed by chemical coating. Since the coating thickness is relatively small, the formation rate of an electroplated coating is generally faster than that of a chemical coating. However, chemical coatings exhibit a more uniform layer formation compared to electroplating.Therefore, the formation of a chemical coating by chemically coating the surface aluminium layer 2 allows the thickness of the surface aluminium layer 2 formed on the surface of the current collector plate body 1 to be more uniform, which improves the corrosion resistance of the surface of the current collector plate body 1 against electrolyte solutions.

[0025] In some embodiments of the present application, the thickness of the current collector plate body 1 is 0.1 mm to 0.5 mm. Alternatively, the thickness of the current collector plate body 1 can be 0.15 mm to 0.25 mm, for example 0.15 mm, 0.20 mm, or 0.25 mm. In this thickness range, the current collector plate body 1 exhibits improved structural strength and stability, thereby ensuring the weld quality of the welded battery cell. At the same time, material consumption is reduced, thus saving material costs.

[0026] In some embodiments of the present application, the thickness of the surface aluminum layer 2 is 0.3 µm to 3.5 µm, for example 0.3 µm, 0.5 µm, 0.8 µm, 1 µm, 1.3 µm, 1.6 µm, 2 µm, 2.4 µm, 2.7 µm, 3 µm, 3.2 µm, or 3.5 µm. Within this thickness range, the surface aluminum layer 2 exhibits improved corrosion and wear resistance. It can effectively protect the outer surface of the current collector plate body 1 from corrosion by electrolytes or other media while simultaneously reducing the material costs of the surface aluminum layer 2.

[0027] In a second aspect, see Fig. 4, shows Fig. 4. A structural diagram of a battery cell according to some embodiments of the present application, specifically a structural diagram of a battery cell with a negative current collector plate. An embodiment of the present application further provides a battery cell comprising a current collector plate according to one of the embodiments of the first aspect.

[0028] Since the current collector plate provided in the present application is able to reduce the corrosion of the current collector plate body 1, i.e. the copper layer, caused by contact of the surface with the electrolyte during operation, the battery cell comprising this current collector plate also exhibits the advantageous effects described above.

[0029] In some embodiments of the present application, the battery cell comprises a winding core 5 and a current collector plate, wherein the tabs of the current collector plate and the winding core 5 are attached by welding. In the welded area of ​​the current collector plate, the surface aluminum layer 2 is oxidized during the welding process to form a dense oxide film coating 7.

[0030] In the present application, the current collector plate body 1 is combined with an aluminum material. This combination can be achieved by electroplating, chemical coating, or extrusion. The current collector plate obtained by this combination is affected by the high temperature generated during welding in such a way that a dense oxide film coating 7 is formed on the surface of the aluminum layer 2, at least in the weld area. Since the dense oxide film coating 7 exhibits good resistance to electrolyte corrosion, it can effectively protect the weld area of ​​the current collector plate during contact with the electrolyte, thus preventing direct corrosion. This improves the overall corrosion resistance of the current collector plate to the electrolyte.

[0031] In some embodiments of the present application, with reference to the Fig. 4 and Fig. 5, where the Fig. 5 a schematic structure diagram of part A in Fig. As shown in Figure 4, the tabs of the current collector plate and the winding core 5 are attached by welding.

[0032] In some embodiments of the present application, the battery cell can comprise a winding core 5 and a current collector plate. In the relevant technology, the current collector plate is frequently welded to the winding core 5. The welding methods can include electric welding, laser welding, and other processes.

[0033] In some embodiments of the present application, the positive tab of the winding core 5 consists of aluminum foil, while the negative tab of the winding core 5 consists of copper foil.

[0034] It is important to understand that the positive tab of the winding core 5 is made of aluminum foil and the negative tab of the winding core 5 is made of copper foil. This significantly reduces the internal resistance and heat generation of the current collector plate, resulting in a considerable extension of the battery cell's lifespan.

[0035] Thirdly, the present application also provides a battery comprising a battery cell according to one of the embodiments described in the second aspect.

[0036] Since the battery cell of the present application, after welding to the current collector plate, is in contact with the electrolyte fluid, and the surface aluminum layer 2 in the welded area is oxidized, forming a corrosion-resistant, dense oxide film coating 7, the welded area of ​​the current collector plate is not easily corroded by the electrolyte fluid. Consequently, the battery containing this battery cell also exhibits the aforementioned advantageous effects.

[0037] For example, the battery includes at least one of the following components: battery module, battery pack, and energy storage container.

Claims

[1] Current collector plate, wherein the current collector plate comprises a current collector plate body (1) and a surface aluminium layer (2), wherein the current collector plate body (1) is made of copper and the surface aluminium layer (2) encloses an outer surface of the current collector plate body (1). [2] Current collector plate according to claim 1, wherein the current collector plate is a positive current collector plate, a surface of the current collector plate body (1) is provided with a liquid inlet opening (11) and the surface aluminium layer (2) covers the wall surface of the liquid inlet opening (11). [3] Current collector plate according to claim 1 or 2, wherein the surface aluminium layer (2) is a coating. [4] Current collector plate according to one of claims 1 to 3, wherein the thickness of the current collector plate body (1) is between 0.1 mm and 0.5 mm. [5] Current collector plate according to one of claims 1 to 4, wherein the thickness of the surface aluminium layer (2) is between 0.3 µm and 3.5 µm. [6] Current collector plate according to any one of claims 1 to 5, wherein the surface aluminium layer (2) is connected to the current collector plate body (1) by extrusion. [7] Current collector plate according to any one of claims 1 to 6, wherein the surface aluminium layer (2) is a coating structure applied to the current collector plate body (1) by electroplating or chemical coating. [8] Current collector plate according to any one of claims 1 to 6, wherein the surface aluminium layer (2) is a thin-film deposition structure deposited on the current collector plate body (1) by thin-film deposition. [9] Battery cell comprising a current collector plate according to any one of claims 1 to 8. [10] Battery cell according to claim 9, wherein the battery cell comprises a winding core (5) and the current collector plate, wherein the tabs of the winding core (5) are attached to the current collector plate by welding, and a dense oxide film coating (7) is formed on the surface of the welded area of ​​the current collector plate, which is formed by the oxidation of at least a part of the surface aluminium layer (2). [11] Battery cell according to claim 10, wherein the tabs of the winding core (5) are attached to the current collector plate by welding. [12] Battery cell according to claim 11, wherein the positive tab of the winding core (5) is made of aluminum foil and the negative tab of the winding core (5) is made of copper foil. [13] Battery, comprising the battery cell according to any one of claims 1 to 12.

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