Convergence plate, battery cell and battery

Abstract

The utility model relates to the technical field of batteries, and provides a confluence plate, a battery cell and a battery to achieve the purpose that after the confluence plate is welded into a part of the battery cell, the surface of a welding area of the confluence plate makes contact with electrolyte, and the welding area of the confluence plate is not prone to being corroded by the electrolyte. The confluence plate comprises a confluence plate body and a surface aluminum layer, the confluence plate body is a copper layer, and the surface aluminum layer wraps the outer surface of the confluence plate body.

Description

[0001] This application claims the priority of a Chinese patent application with the application number 202311750512.5, which was filed with the Chinese Patent Office on December 18, 2023. The entire content of the above application is incorporated herein by reference. Technical Field

[0002] This application relates to the technical field of batteries, and in particular, to a bus bar, a battery cell, and a battery. Background Art

[0003] The bus bar structure is an integral part of a battery cell and is commonly used in the production process of various batteries, such as lithium-ion batteries. In the related art, batteries usually use laser welding to weld the bus bar to the exposed tab of the wound core. The bus bar is generally divided into a positive bus bar and a negative bus bar.

[0004] In the related art, the base material of the bus bar is aluminum. The bus bar made of aluminum base material has a relatively high resistance, resulting in a relatively high internal resistance of the battery cell and serious internal heat generation of the battery cell. There are also some bus bars made of other materials with lower internal resistance, but the surfaces of these bus bars are easily corroded by the electrolyte, causing performance defects. Summary of the Utility Model

[0005] In view of this, this application provides a bus bar, a battery cell, and a battery to improve the problem that the bus bar is easily corroded by the electrolyte.

[0006] The technical solution adopted by this application to solve the above technical problems is as follows:

[0007] In a first aspect, this application provides a bus bar. The bus bar includes a bus bar body and a surface aluminum layer. The bus bar body is a copper layer, and the surface aluminum layer covers the outer surface of the bus bar body.

[0008] In some embodiments of this application, the bus bar is a positive bus bar. Liquid inlet holes are formed on the surface of the bus bar body, and the surface aluminum layer also covers the pore walls of the liquid inlet holes.

[0009] In some embodiments of this application, the surface aluminum layer is a coating layer.

[0010] In some embodiments of this application, the thickness of the bus bar body is from 0.1 millimeter to 0.5 millimeter.

[0011] In some embodiments of this application, the thickness of the surface aluminum layer is from 0.3 micrometer to 3.5 micrometers.

[0012] In a second aspect, this application further provides a battery cell, including the bus bar as described in any one of the above.

[0013] In some embodiments of the present application, the battery cell includes a wound core and the current collector plate. The current collector plate and the tab of the wound core are fixed by welding. In the welding area of the current collector plate, a dense oxide film layer formed by oxidizing at least a part of the surface aluminum layer is formed on the surface of the welding area.

[0014] In some embodiments of the present application, the current collector plate is fixed by welding to the tab of the wound core.

[0015] In some embodiments of the present application, the positive tab of the wound core is an aluminum foil, and the negative tab of the wound core is a copper foil.

[0016] In a third aspect, the present application further provides a battery, including the battery cell as described in any one of the above.

[0017] In summary, due to the adoption of the above technical solutions, the present application has at least the following beneficial effects:

[0018] For a current collector plate, a battery cell and a battery provided by the present application, mainly by changing the material of the current collector plate body from the aluminum material used in the traditional current collector plate to a copper material, the internal resistance of the current collector plate during operation can be reduced, and the probability of the current collector plate generating heat during operation can be greatly reduced. Then, a surface aluminum layer is coated on the outer surface of the copper current collector plate body. When the current collector plate body is welded to become a part of the battery cell, the high temperature generated by the welding can be utilized to cause a chemical reaction between the surface aluminum layer and oxygen in the air, thereby generating a dense oxide film layer in the welding area of the current collector plate body. This dense oxide film layer has a good corrosion resistance effect and is not easily chemically reacted with the electrolyte. Therefore, during the production and operation of the battery cell, when the current collector plate in the battery cell comes into contact with the electrolyte, the electrolyte directly contacts the dense oxide film layer in the welding area, making it difficult for the electrolyte to directly corrode the welding area, thereby improving the corrosion of the welding area of the current collector plate caused by the contact between the surface after welding and the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present application and do not limit the present application, where:

[0020] Figure 1 is a schematic cross-sectional structure diagram of the current collector plate provided by the embodiment of the present application;

[0021] Figure 2 is a schematic structure diagram of the current collector plate provided by the embodiment of the present application;

[0022] Figure 3 is Figure 2 a schematic cross-sectional view of the current collector plate in

[0023] Figure 4 It is a schematic structural diagram of the battery cell provided by the embodiment of the present application;

[0024] Figure 5 is Figure 4 a schematic structural diagram of part A in

[0025] The attached drawings are described as follows:

[0026] 1. Busbar body; 11. Liquid inlet hole; 2. Surface aluminum layer; 5. Winding core; 7. Dense oxide film layer. Specific embodiments

[0027] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the attached drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope protected by the present application.

[0028] In the description of the present application, it should be understood that the terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0029] In the present application, the term "exemplary" is used to mean "serving as an example, illustration, or description". Any embodiment described as "exemplary" in the present application is not necessarily construed as being more preferred or having more advantages than other embodiments. For any person skilled in the art to implement and use the present application, the following description is given. In the following description, details are set forth for the purpose of explanation. It should be understood that those skilled in the art can recognize that the present application can also be implemented without using these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope in accordance with the principles disclosed in the present application.

[0030] A busbar is a component used to collect the electrical energy of a battery cell to an energized device to achieve power transmission or transfer electrical energy to the battery cell when charging the battery cell. The busbar is usually connected to the winding core to form a battery cell.

[0031] The busbar is generally connected to the tab of the winding core, and the connection method can generally be welding. In the related art, laser welding is usually used to ensure the welding strength and welding efficiency.

[0032] However, in the related art, the base material of the bus bar is aluminum. However, when aluminum is used as the base material of the bus bar, the internal resistance of the battery cell is too high, and the internal heat generation of the battery cell is relatively serious. It not only consumes electric energy, but may also cause abnormal heating and burn out the battery cell, resulting in the failure of the battery to operate. Although other materials with low internal resistance can be used to manufacture the bus bar in the related art, the surface of the bus bar made of most materials with low internal resistance is prone to corrosion with the electrolyte.

[0033] Based on the above-mentioned bus bar, please refer to Figure 1 , Figure 1 which is a schematic cross-sectional structure diagram of the bus bar provided by an embodiment of the present application. The present application provides a bus bar, which includes a bus bar body 1 and a surface aluminum layer 2. The bus bar body 1 is a copper layer, and the surface aluminum layer 2 covers the outer surface of the bus bar body 1.

[0034] It should be understood that the way of covering the surface aluminum layer 2 outside the bus bar body 1 can be a fitting way or a tightly fixed way.

[0035] It can be understood that the bus bar in the related art is a sheet made of aluminum, and generally there is no composite layer structure on the surface of the bus bar. Since the bus bar made of aluminum material is economical but has a high internal resistance, when the bus bar is in the working state, it is easy to generate heat during the input and output of electric energy due to its own high internal resistance, consuming electric energy, easily burning out the components near the bus bar, and reducing the service life of the battery cell.

[0036] The beneficial effects of the present application: The present application changes the bus bar body 1 from the aluminum material used in the traditional bus bar to a copper material, so as to reduce the internal resistance of the bus bar during operation and greatly reduce the probability of heat generation of the bus bar during operation. Then, a surface aluminum layer 2 is covered on the outer side of the copper bus bar body 1, which enables the bus bar body 1 to utilize the high-temperature conditions generated by welding when it is welded into a part of the battery cell, so that the surface aluminum layer 2 reacts chemically with the oxygen in the air to generate a dense oxide film layer 7 in the welding area of the bus bar. The dense oxide film layer 7 has a good corrosion resistance effect and is not easy to chemically react with the electrolyte. Therefore, during the production and operation of the battery cell, when the bus bar in the battery cell comes into contact with the electrolyte, the electrolyte directly contacts the dense oxide film layer 7 in the welding area, making it difficult for the electrolyte to directly corrode the welding area, thereby improving the situation that the surface of the bus bar corrodes the welding area of the bus bar after welding when it comes into contact with the electrolyte.

[0037] In some embodiments of the present application, please refer to Figure 2 and Figure 3 , Figure 2Schematic structural diagram of the bus bar provided by the embodiment of the present application Figure 3 Provided by the embodiment of the present application Figure 2 Schematic cross-sectional view of the bus bar in the middle. As an example, the bus bar is a positive bus bar. Liquid inlet holes 11 for injecting electrolyte into the interior of the cell housing are formed on the surface of the bus bar body 1, and the surface aluminum layer 2 also covers the hole walls of the liquid inlet holes 11.

[0038] It can be understood that during the production of the cell, the bus bar body 1 is plated with a coating of aluminum material by electroplating or electroless plating, and then the plated bus bar body 1 is oxidized under high-temperature conditions generated during the welding process with the core to form a dense oxide film layer 7 on the coating. Then it is assembled with the cell housing. After the assembly is completed, electrolyte needs to be injected into the liquid inlet holes 11 formed on the surface of the positive bus bar. During the injection of the electrolyte, it is inevitable that the electrolyte comes into contact with the liquid inlet holes 11.

[0039] It can be understood that the bus bar can generally be divided into a positive bus bar and a negative bus bar. Liquid inlet holes 11 for injecting electrolyte into the cell are generally provided on the surface of the positive bus bar. Generally speaking, the electrolyte is likely to corrode the liquid inlet holes 11 during the injection process. In the present application, when the bus bar is a positive bus bar, the hole walls of the liquid inlet holes 11 are also coated with a surface aluminum layer 2. Under the high-temperature conditions generated during the welding process, a dense oxide film layer 7 is formed on the surface of the surface aluminum layer 2. Thus, the hole walls of the liquid inlet holes 11 can be made to have the ability to resist the corrosion of the electrolyte during the injection process.

[0040] It should be noted that under normal temperature conditions, the surface of the surface aluminum layer 2 will react with oxygen to generate a relatively thin dense oxide film layer 7 under normal temperature conditions. Under high-temperature conditions, it will react quickly with oxygen to generate a relatively thick dense oxide film layer 7. And the high temperature generated by welding can meet the high-temperature conditions, and at least part of the surface aluminum layer 2 reacts quickly with oxygen to generate a dense oxide film layer 7.

[0041] In some embodiments of the present application, the surface aluminum layer 2 is a coating.

[0042] It can be understood that the bonding method between the surface aluminum layer 2 and the busbar body 1 can be to form a composite structure by extruding the surface aluminum layer 2 onto the busbar body 1, or to form a coating structure by electroplating or electroless plating the surface aluminum layer 2 on the busbar body 1, or to deposit the surface aluminum layer 2 on the busbar body 1 by thin film deposition to produce a thin film deposition structure. Among these, the thickness of the coating structure formed by electroplating or electroless plating the surface aluminum layer 2 on the busbar body 1 is more uniform than that of the composite structure formed by extruding the surface aluminum layer 2 onto the busbar body 1, and is more economical and practical than the thin film deposition structure produced by depositing the surface aluminum layer 2 on the busbar body 1 by thin film deposition.

[0043] Exemplarily, the surface aluminum layer 2 can be a chemical coating.

[0044] It can be understood that a coating is plated on the surface of the busbar body 1. Generally, the surface aluminum layer 2 can be electroplated into an electroplated layer by electroplating; or the surface aluminum layer 2 can be plated into a chemical coating by electroless plating. Since the thickness of the coating is small, although the speed of electroplating to produce an electroplated layer is faster than that of electroless plating to produce a chemical coating, the formation effect of the chemical coating is more uniform than that of the electroplated layer. Therefore, forming the surface aluminum layer 2 into a chemical coating by electroless plating can make the thickness of the surface aluminum layer 2 on the surface of the busbar body 1 uniform, which is more conducive to improving the anti-electrolyte corrosion effect on the surface of the busbar body 1.

[0045] In some embodiments of the present application, the thickness of the busbar body 1 is 0.1 mm to 0.5 mm. Optionally, the thickness of the busbar body 1 can be 0.15 mm to 0.25 mm, such as 0.15 mm, 0.20 mm, 0.25 mm, etc. Within this thickness range, the busbar body 1 has better structural strength and stability, thereby ensuring the welding quality of the battery cells formed by welding, and at the same time reducing the material consumption and saving the material cost.

[0046] In some embodiments of the present application, the thickness of the surface aluminum layer 2 is 0.3 μm to 3.5 μm, such as 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, etc. Within this thickness range, the surface aluminum layer 2 has better corrosion resistance and wear resistance, and can effectively prevent the outer surface of the busbar body 1 from being corroded by the electrolyte or other media, while reducing the material cost of the surface aluminum layer 2.

[0047] In a second aspect, see Figure 4 , Figure 4Schematic diagram of the structure of the battery cell provided by the embodiments of the present application. Specifically, it is a schematic diagram of the structure of the battery cell including a negative electrode current collector plate. The present application also provides a battery cell including the current collector plate described in any of the above embodiments.

[0048] Since the current collector plate in the present application can improve the situation where the surface of the current collector plate body 1 comes into contact with the electrolyte liquid during operation, thereby corroding the current collector plate body 1, that is, the copper layer, the battery cell including this current collector plate also has the above beneficial effects.

[0049] In some embodiments of the present application, the battery cell includes a wound core 5 and a current collector plate. The current collector plate and the tab of the wound core 5 are fixed by welding. In the welding area of the current collector plate, the surface aluminum layer 2 is oxidized during welding to form a dense oxide film layer 7.

[0050] In the present application, the current collector plate body 1 and the aluminum material are compounded. The compounding method can be electroplating, electroless plating, extrusion, etc. The compounded current collector plate is subjected to the high-temperature conditions generated by welding, so that at least in the welding area, a dense oxide film layer 7 is formed on the surface of the aluminum layer 2 of the aluminum material. Since the dense oxide film layer 7 has good resistance to electrolyte corrosion, it can protect the welding area of the current collector plate from being directly corroded when in contact with the electrolyte. In this way, the overall electrolyte corrosion resistance of the current collector plate is improved.

[0051] In some embodiments of the present application, refer to Figure 4 and Figure 5 , Figure 5 is a schematic diagram of part A provided by the embodiments of the present application. The current collector plate and the tab of the wound core 5 are fixed by welding. Figure 4 In some embodiments of the present application, the battery cell may include a wound core 5 and a current collector plate. In the related art, the current collector plate and the wound core 5 are often welded, and the welding methods may include electric welding, laser welding, etc.

[0052] In some embodiments of the present application, the positive tab of the wound core 5 is an aluminum foil, and the negative tab of the wound core 5 is a copper foil.

[0053] It can be understood that when the positive tab of the wound core 5 is an aluminum foil and the negative tab of the wound core 5 is a copper foil, the internal resistance and heat generation of the current collector plate are greatly reduced, and the life of the battery cell can be greatly improved.

[0054]

[0055] In the third aspect, the present application also provides a battery including the battery cell described in any of the above embodiments.

[0056] Since the cell and the bus bar in the present application are in contact with the electrolytic liquid after welding, and within the welding area, the surface aluminum layer 2 is oxidized to form a dense oxide film layer 7 with corrosion resistance, thus achieving the purpose that the welding area of the bus bar is not easily corroded by the electrolyte. Therefore, the battery including this cell also has the above beneficial effects.

[0057] As an example, the battery includes at least one of a battery module, a battery pack, and an energy storage container.

[0058] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only an example and does not constitute a limitation to the present application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to the present application. Such modifications, improvements, and corrections are proposed in the present application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of the present application.

[0059] Meanwhile, the present application uses specific terms to describe the embodiments of the present application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the present application can be appropriately combined.

[0060] Similarly, it should be noted that, in order to simplify the description of the present application disclosure and thus help the understanding of one or more application embodiments, in the previous description of the embodiments of the present application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the object of the present application are more than those mentioned in the claims. In fact, the features of the embodiment are fewer than all the features of the above-disclosed single embodiment.

[0061] For each patent, patent application, patent application publication, and other materials cited in the present application, such as articles, books, specifications, publications, documents, etc., hereby incorporate their entire contents into the present application as references, except for the application history documents that are inconsistent with or conflict with the content of the present application, and also except for the documents that limit the broadest scope of the claims of the present application (currently or subsequently attached to the present application). It should be noted that if there are inconsistencies or conflicts between the descriptions, definitions, and / or uses of terms in the attached materials of the present application and the content of the present application, the descriptions, definitions, and / or uses of terms in the present application shall prevail.

Claims

1. A busbar, characterized in that: The busbar comprises a busbar body (1) and a surface aluminum layer (2); the busbar body (1) is a copper layer, and the surface aluminum layer (2) covers the outer surface of the busbar body (1).

2. The busbar according to claim 1, characterized in that: The collector plate is a positive collector plate, a liquid inlet hole (11) is provided on the surface of the collector plate body (1), and the surface aluminum layer (2) also covers the hole wall of the liquid inlet hole (11).

3. The busbar according to claim 1, characterized in that: The surface aluminum layer (2) is a plated layer.

4. The busbar according to claim 1, characterized in that: The thickness of the busbar body (1) is 0.1 mm to 0.5 mm.

5. The busbar according to claim 1, characterized in that: The thickness of the surface aluminum layer (2) is 0.3 micrometers to 3.5 micrometers.

6. A battery cell, characterized in that: Comprising the busbar as claimed in any one of claims 1 to 5.

7. The battery cell according to claim 6, characterized in that: It comprises a winding core (5) and a busbar, wherein the busbar and the winding core (5) are fixed by welding, and within the welding area of ​​the busbar, a dense oxide film layer (7) formed by oxidation of at least a portion of the surface aluminum layer (2) is formed on the surface of the welding area.

8. The battery cell according to claim 7, characterized in that: The busbar is fixed to the pole tab of the winding core (5) by welding.

9. The battery cell according to claim 8, characterized in that: The positive electrode tab of the winding core (5) is aluminum foil, and the negative electrode tab of the winding core (5) is copper foil.

10. A battery, characterized in that: Comprising the battery cell as claimed in any one of claims 6 to 9.

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