Cylindrical battery

Abstract

The utility model relates to battery technical field discloses a cylindrical battery, including the shell and setting in the negative pole current collector disc of shell inside, the shell includes with the first cover plate of negative pole current collector disc connection, the first cover plate includes the substrate and sets up in the multiple protruding parts of substrate's one side near negative pole current collector disc, the side of multiple protruding parts away from the substrate is located in the same plane, and is used for with negative pole current collector disc connection. Negative pole current collector disc and multiple one side of the protruding part located in the same plane can closely adhere, reduce the clearance of protruding part and negative pole current collector disc contact surface department, avoid the welding place of negative pole current collector disc and first cover plate and appear the situation such as false welding or overwelding, and multiple interval setting protruding parts respectively with negative pole current collector disc contact, even if there is protruding part and negative pole current collector disc cannot closely contact, other position's protruding part still can closely contact with negative pole current collector disc, improve negative pole current collector disc and the reliability of first cover plate close connection.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and specifically to a cylindrical battery. Background Technology

[0002] With the increasing market demand for all-tab lithium-ion batteries, both power tools and hybrid electric vehicles require battery modules to provide high-power operation. However, the reliability of the welding between the battery cell and the casing has become a bottleneck for the commercialization of all-tab lithium-ion batteries.

[0003] A cylindrical battery is a type of all-tab lithium-ion battery packaging. It includes a housing and a cell, a positive current collector, a negative current collector, and a positive terminal block disposed inside the housing. The housing includes a side plate and a first cover plate and a second cover plate disposed at intervals along the axial direction of the cylindrical battery on both sides of the side plate. The two ends of the cell are connected to the positive current collector and the negative current collector, respectively. The positive current collector is connected to the positive terminal block, the positive terminal block is connected to the second cover plate, and the negative current collector is directly connected to the first cover plate.

[0004] In existing cylindrical batteries, the side of the first cover plate connected to the negative current collector is set to be flat. When welding the negative current collector to the flat first cover plate, due to the poor flatness of the first cover plate, the fit between the negative current collector and the first cover plate is low and there are many gaps. The welding joint between the negative current collector and the first cover plate is prone to problems such as poor welding or over-welding, resulting in poor reliability of the connection between the negative current collector and the first cover plate. Utility Model Content

[0005] The purpose of this invention is to overcome the problems of poor flatness of the first cover plate in the prior art, low fit and large gap when the negative electrode current collector is fixedly connected to the planar first cover plate, and easy occurrence of incomplete or over-welded joints at the welding point between the negative electrode current collector and the first cover plate, resulting in poor reliability of the connection between the negative electrode current collector and the first cover plate. This invention provides a cylindrical battery that improves the reliability of the tight connection between the negative electrode current collector and the first cover plate.

[0006] To achieve the above objectives, the present invention provides a cylindrical battery, including a housing and a negative electrode current collector disposed inside the housing. The housing includes a first cover plate connected to the negative electrode current collector. The first cover plate includes a substrate and a plurality of protrusions disposed on the side of the substrate near the negative electrode current collector. The sides of the plurality of protrusions away from the substrate are located on the same plane and are used to connect to the negative electrode current collector.

[0007] In some embodiments, the substrate and the plurality of protrusions of the first cover plate are integrally formed by molding.

[0008] In some embodiments, the protrusions are fixedly connected to the negative electrode current collector by welding; and / or a plurality of the protrusions are evenly spaced along the circumference of the first cover plate.

[0009] In some embodiments, along the axial direction of the cylindrical battery, the projection of the welding position of the protrusion and the negative current collector does not coincide with the projection of the welding position of the negative current collector and the cell of the cylindrical battery.

[0010] In some embodiments, the width of the protrusion is set to be more than three times the width of the weld between the protrusion and the negative current collector, and the length of the protrusion is set to be more than 1.1 times the length of the weld between the protrusion and the negative current collector.

[0011] In some embodiments, the housing is cylindrical and made of corrosion-resistant material.

[0012] In some embodiments, the housing is made of nickel-plated steel.

[0013] In some embodiments, the cylindrical battery further includes an adsorption element for adsorbing free electrolyte within the cylindrical battery.

[0014] In some embodiments, the adsorption element is disposed on the side of the substrate near the negative electrode current collector.

[0015] In some embodiments, the adsorbent is made of aramid material.

[0016] Through the above technical solution, the side of the multiple protrusions away from the substrate is located on the same plane, ensuring the flatness of the multiple protrusions connected to the negative current collector. When the negative current collector is connected to the protrusions, the negative current collector and the side of the multiple protrusions located on the same plane can be tightly fitted, reducing the gap at the contact surface between the protrusions and the negative current collector, and avoiding situations such as incomplete soldering or over-soldering at the welding point between the negative current collector and the first cover plate. Moreover, the multiple protrusions arranged at intervals contact the negative current collector respectively. Even if there is a problem that one or some protrusions cannot make close contact with the negative current collector, the protrusions located at other positions on the first cover plate can still make close contact with the negative current collector, ensuring the area of ​​close contact between the protrusions and the negative current collector, and improving the reliability of the tight connection between the negative current collector and the first cover plate.

[0017] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings: Figure 1 This is a schematic diagram of the structure of the cylindrical battery casing disclosed in this utility model; and Figure 2 This is a top view of the first cover plate of the cylindrical battery disclosed in this utility model.

[0019] Explanation of reference numerals in the attached figures 1. Shell; 2. First cover plate; 3. Base plate; 4. Protrusion; 5. Adsorption component. Detailed Implementation

[0020] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0021] In existing cylindrical batteries, the side of the first cover plate connected to the negative current collector is set to be flat. When welding the negative current collector to the flat first cover plate, due to the poor flatness of the first cover plate, the fit between the negative current collector and the first cover plate is low and there are many gaps. The welding joint between the negative current collector and the first cover plate is prone to problems such as poor welding or over-welding, resulting in poor reliability of the connection between the negative current collector and the first cover plate.

[0022] Based on this, the present invention provides a cylindrical battery. See also... Figures 1 to 2 As shown, the cylindrical battery includes a housing 1 and a negative electrode current collector disposed inside the housing 1. The housing 1 includes a first cover plate 2 connected to the negative electrode current collector. The first cover plate 2 includes a substrate 3 and a plurality of protrusions 4 disposed on the side of the substrate 3 near the negative electrode current collector. The sides of the plurality of protrusions 4 away from the substrate 3 are located on the same plane and are used to connect to the negative electrode current collector.

[0023] The sides of the multiple protrusions 4 furthest from the substrate 3 are located on the same plane, thereby ensuring the flatness of the multiple protrusions 4 connected to the negative current collector. When the negative current collector is connected to the protrusions 4, the negative current collector and one side of the multiple protrusions 4 located on the same plane can fit tightly together, reducing the gap at the contact surface between the protrusions 4 and the negative current collector, and avoiding situations such as incomplete welding or over-welding at the welding point between the negative current collector and the first cover plate 2. Moreover, the multiple protrusions 4 arranged at intervals contact the negative current collector respectively. Even if there is a problem that one or some protrusions 4 cannot make tight contact with the negative current collector, the protrusions 4 located at other positions on the first cover plate 2 can still make tight contact with the negative current collector, ensuring the area of ​​tight contact between the protrusions 4 and the negative current collector, and improving the reliability of the tight connection between the negative current collector and the first cover plate 2.

[0024] In the above, the casing 1 of the cylindrical battery is cylindrical, and the first cover plate 2 is circular.

[0025] Preferably, the cylindrical battery proposed in this invention is a multi-tab cylindrical battery.

[0026] In the above, the substrate 3 and multiple protrusions 4 of the first cover plate 2 are integrally formed by mold pressing. The integrally formed first cover plate 2 by mold pressing is simple and efficient in manufacturing process, and at the same time can ensure that the side of the multiple protrusions 4 of the first cover plate 2 away from the substrate 3 is located on the same plane, so as to improve the reliability of the tight connection between the protrusions 4 and the negative electrode current collector.

[0027] Alternatively, the base plate 3 of the first cover plate 2 and multiple protrusions 4 can be stamped together.

[0028] In some embodiments, the protrusion 4 is fixedly connected to the negative current collector by welding. Welding can securely connect the protrusion 4 and the negative current collector, and ensure the strength of the connection between the two.

[0029] In the above, for example Figure 2 As shown, multiple protrusions 4 are evenly spaced along the circumference of the first cover plate 2. The multiple protrusions 4 evenly spaced along the circumference of the first cover plate 2 can be evenly connected to the negative electrode current collector, ensuring the uniformity and firmness of the connection between the two.

[0030] Alternatively, the protrusion 4 and the negative electrode current collector can be welded by a laser welding machine.

[0031] Along the axial direction of the cylindrical battery, if the projection of the welding position between the protrusion 4 and the negative current collector coincides with the projection of the welding position between the negative current collector and the cylindrical battery cell, it will easily cause over-welding or burn-through of the negative current collector, affecting its effectiveness. Therefore, along the axial direction of the cylindrical battery, the projection of the welding position between the protrusion 4 and the negative current collector does not coincide with the projection of the welding position between the negative current collector and the cylindrical battery cell, thereby ensuring the effectiveness of the negative current collector and the stable operation of the cylindrical battery.

[0032] In the above, for example Figure 2 As shown, the shape of the protrusion 4 is as follows Figure 2 The rectangle shown. And the length of the protrusion 4 of the rectangle extends radially along the first cover plate 2.

[0033] Those skilled in the art will understand that the shape of the protrusion 4 of this invention is not limited to the rectangular shape described above. Alternatively, the protrusion 4 can be radially oriented and extend along the radial direction of the first cover plate 2 to improve the reliability and safety of the connection between the negative electrode current collector and the protrusion 4.

[0034] In the above description, the width of the protrusion 4 is set to be at least three times the width of the weld between the protrusion 4 and the negative current collector, and the length of the protrusion 4 is set to be at least 1.1 times the length of the weld between the protrusion 4 and the negative current collector. The ratio of the length and width of the weld to the protrusion 4 is determined according to the welding process to improve the safety and reliability of the welding effect between the protrusion 4 and the negative current collector.

[0035] The electrolyte inside the cylindrical battery is corrosive and easily reacts chemically with the casing 1. The anti-corrosion material can prevent the casing 1 from being corroded and damaged. Therefore, the casing 1 is made of anti-corrosion material.

[0036] Alternatively, the inner side of the housing 1 can be coated with an anti-corrosion material.

[0037] Low-carbon steel or ultra-low-carbon steel is prone to corrosion, so a nickel-iron alloy layer is usually formed on the surface of low-carbon steel or ultra-low-carbon steel through a pre-plating nickel process to improve corrosion resistance. The existing shell 1 is mainly made of low-carbon steel or ultra-low-carbon steel. In order to improve the corrosion resistance of the shell 1, the shell 1 of this utility model is made of nickel-plated steel.

[0038] When the electrolyte is injected into the cylindrical battery, it flows from the top to the bottom of the cylindrical casing 1, providing electrolyte for the cylindrical battery cell. The electrolyte that is not absorbed by the cell flows out from the bottom of the cell and is free in the cylindrical battery. The free electrolyte will affect the formation of the CEI film (interfacial electrochemical film) and SEI film (solid electrolyte interfacial film) of the cylindrical battery, thereby affecting the electrical performance of the cylindrical battery.

[0039] Based on this, the cylindrical battery also includes an adsorption element 5, which is used to adsorb the free electrolyte inside the cylindrical battery. The adsorption element 5 can effectively adsorb the free electrolyte, ensuring the normal formation of the CEI film (interfacial electrochemical film) and SEI film (solid electrolyte interfacial film) of the cylindrical battery, ensuring the electrical performance of the cylindrical battery, and avoiding the waste of electrolyte.

[0040] Furthermore, the electrolyte can be removed from the adsorption element 5 for reuse, thereby improving the utilization rate of the electrolyte.

[0041] In the above, for example Figure 1 As shown, the adsorption element 5 is disposed on the side of the substrate 3 near the negative electrode current collector. The adsorption element 5 disposed on the side of the substrate 3 near the negative electrode current collector can effectively adsorb free electrolyte, improve the electrolyte retention of the cylindrical battery cell, and extend the cycle life of the cylindrical battery.

[0042] Aramid materials have good adsorption properties and do not react with electrolytes; therefore, the adsorbent 5 is made of aramid material.

[0043] Those skilled in the art will understand that the adsorption element 5 of this utility model is not limited to being made of the aforementioned aramid material; other materials that can adsorb electrolyte and do not react with electrolyte should also fall within the protection scope of this utility model.

[0044] Specifically, aramid material is composited on the side of substrate 3 near the negative electrode current collector to form adsorption element 5.

[0045] The center position of the substrate 3 of the first cover plate 2, on the side away from the negative electrode current collector, is used for the assembly welding between batteries.

[0046] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0049] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A cylindrical battery, comprising a housing (1) and a negative electrode current collector disposed inside the housing (1), the housing (1) comprising a first cover plate (2) connected to the negative electrode current collector, characterized in that, The first cover plate (2) includes a substrate (3) and a plurality of protrusions (4) disposed on the side of the substrate (3) near the negative electrode current collector. The sides of the plurality of protrusions (4) away from the substrate (3) are located on the same plane and are used to connect with the negative electrode current collector.

2. The cylindrical battery according to claim 1, characterized in that, The base plate (3) and the plurality of protrusions (4) of the first cover plate (2) are integrally formed by molding.

3. The cylindrical battery according to claim 1, characterized in that, The protrusion (4) is fixedly connected to the negative electrode current collector by welding; and / or The multiple protrusions (4) are evenly spaced along the circumference of the first cover plate (2).

4. The cylindrical battery according to claim 3, characterized in that, Along the axial direction of the cylindrical battery, the projection of the welding position of the protrusion (4) and the negative current collector does not coincide with the projection of the welding position of the negative current collector and the cell of the cylindrical battery.

5. The cylindrical battery according to claim 3, characterized in that, The width of the protrusion (4) is set to be more than 3 times the width of the weld between the protrusion (4) and the negative electrode current collector, and the length of the protrusion (4) is set to be more than 1.1 times the length of the weld between the protrusion (4) and the negative electrode current collector.

6. The cylindrical battery according to claim 1, characterized in that, The shell (1) is cylindrical and made of corrosion-resistant material.

7. The cylindrical battery according to claim 6, characterized in that, The housing (1) is made of nickel-plated steel.

8. The cylindrical battery according to any one of claims 1-7, characterized in that, The cylindrical battery also includes an adsorption element (5), which is used to adsorb the free electrolyte inside the cylindrical battery.

9. The cylindrical battery according to claim 8, characterized in that, The adsorption element (5) is disposed on the side of the substrate (3) near the negative electrode current collector.

10. The cylindrical battery according to claim 9, characterized in that, The adsorbent (5) is made of aramid material.

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