Secondary battery

Abstract

The utility model provides a kind of secondary battery.The secondary battery includes pole, current collecting member and protective layer.Pole is used to realize the electrical connection of secondary battery and outside;Current collecting member has the welding mark formed by welding with pole, and there is preset interval between the welding mark and the circumference of current collecting member;Protective layer is arranged on the side of current collecting member away from pole, and the protective layer covers at least the part of current collecting member with welding mark.The utility model solves the problem that the welding mark formed by welding current collecting member and pole is easy to blacken in the prior art.

Description

Technical Field

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

[0002] In the manufacturing process of secondary batteries, current collectors are typically connected to the cell tabs and cover plate terminals via welding to achieve indirect connection between the cell tabs and cover plate terminals. For example, in the laser welding process, for the copper current collector used in the negative electrode of the secondary battery, copper oxide and cuprous oxide are generated under the high temperature of laser welding. The weld marks and slag of the laser-welded copper current collector contain these copper oxides. During the formation stage, due to the influence of multiple factors such as electrolyte and formation current, these copper oxides will eventually decompose into black copper oxide on the surface of the weld mark and accumulate continuously, causing the weld mark to turn completely black, which in turn affects the conductivity of the weld.

[0003] Therefore, in the existing technology, there is a problem that the weld marks formed by welding the current collector and the pole are prone to blackening. Utility Model Content

[0004] The main purpose of this invention is to provide a secondary battery to solve the problem that the weld marks formed by welding the current collector and the electrode in the prior art are prone to blackening.

[0005] To achieve the above objectives, according to one aspect of the present invention, a secondary battery is provided, comprising: a terminal post for electrically connecting the secondary battery to an external source; a current collector for welding the current collector to the terminal post and having a weld mark formed by welding the current collector to the terminal post, wherein the weld mark and the periphery of the current collector are spaced apart by a predetermined interval; and a protective layer disposed on the side of the current collector away from the terminal post, wherein the protective layer at least covers the portion of the current collector having the weld mark.

[0006] Furthermore, the shortest distance from any point on the solder mark to the periphery of the current collector is greater than or equal to 2.5 mm.

[0007] Furthermore, the longest distance from any point of the solder mark to the periphery of the current collector shall not exceed 3.5 mm.

[0008] Furthermore, the shortest distance from any point on the solder mark to the periphery of the protective layer is greater than or equal to 2.5 mm.

[0009] Furthermore, the protective layer consists of a base film and an adhesive coated on the base film, and the protective layer is attached to the current collector by the adhesive.

[0010] Furthermore, the thickness of the protective layer is greater than or equal to 50 μm, wherein the thickness of the adhesive is greater than or equal to 25 μm.

[0011] Furthermore, the base film is made of polyimide or polyethylene terephthalate.

[0012] Furthermore, the adhesive is an acrylate.

[0013] Furthermore, the protective layer is adhered to the current collection component, and the peel force of the protective layer is ≥0.3N / mm.

[0014] Furthermore, the solder mark shape is either circular or polygonal.

[0015] Applying the technical solution of this utility model, the secondary battery of this application includes terminals, current collectors, and a protective layer. The terminals are used to achieve electrical connection between the secondary battery and the outside; the current collector has a weld mark formed by welding with the terminals, and there is a predetermined gap between the weld mark and the periphery of the current collector; the protective layer is disposed on the side of the current collector away from the terminals, and the protective layer at least covers the portion of the current collector with the weld mark. When using the secondary battery of this application, because the secondary battery has a protective layer, and the protective layer can cover the weld mark on the current collector, the weld mark can be protected by the protective layer to prevent contact between the weld mark on the current collector and the electrolyte, thereby effectively preventing the weld mark from blackening and effectively ensuring the performance of the secondary battery. Therefore, the secondary battery of this application effectively solves the problem of easy blackening of the weld mark formed by welding the current collector and the terminals in the prior art. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0017] Figure 1 A schematic diagram of a current collection component with a protective layer according to a specific embodiment of the present invention is shown;

[0018] Figure 2 It shows Figure 1 A schematic diagram of the current collection component.

[0019] The above figures include the following reference numerals:

[0020] 10. Current collection component; 11. Weld stamp; 20. Protective layer. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0024] A secondary battery typically comprises a casing, a cell, and a cover plate. The casing has an opening, the cell is housed within the casing's internal space, the cover plate seals the casing opening, and the cell has tabs. A cover plate terminal is mounted on the cover plate, and the tabs are connected to the cover plate terminal via current collectors. During the assembly of the secondary battery, the current collector is welded to both the cell tabs and the cover plate terminal to achieve an indirect connection between them. The current collector and cover plate terminal are usually laser-welded. For the copper current collector used in the negative electrode of the secondary battery, the high temperature of laser welding generates copper oxide and cuprous oxide. The weld marks and slag after laser welding of the copper current collector contain these copper oxides. During the formation stage, due to the influence of multiple factors such as the electrolyte and formation current, these copper oxides eventually decompose into black copper oxide on the weld mark surface, accumulating and causing the weld mark to completely blacken, thus affecting the conductivity of the weld.

[0025] To address the problem of blackening of weld marks formed by welding current collectors and terminals in existing technologies, this application provides a secondary battery.

[0026] like Figure 1 and Figure 2As shown, the secondary battery in this application includes terminals (not shown), a current collector 10, and a protective layer 20. The terminals are used to connect the secondary battery to the outside; the current collector 10 is welded to the terminals and has a weld mark 11 formed by welding with the terminals, with a predetermined interval between the weld mark 11 and the periphery of the current collector; the protective layer 20 is disposed on the side of the current collector 10 away from the terminals, and the protective layer 20 at least covers the portion of the current collector 10 with the weld mark 11. When using the secondary battery in this application, because the secondary battery has a protective layer 20, and the weld mark 11 on the current collector 10 can be covered by the protective layer 20, the weld mark 11 can be protected by the protective layer 20 to prevent contact between the weld mark 11 on the current collector 10 and the electrolyte, thereby effectively preventing the weld mark 11 from blackening, thus effectively ensuring the performance of the secondary battery. Therefore, the secondary battery in this application effectively solves the problem of easy blackening of the weld mark formed by welding the current collector and terminals in the prior art.

[0027] Optionally, the shortest distance from any point of the solder mark 11 to the periphery of the current collector 10 is greater than or equal to 2.5 mm. Furthermore, the longest distance from any point of the solder mark 11 to the periphery of the current collector 10 does not exceed 3.5 mm. In other words, in this application, the terminal post will not be welded to the periphery of the current collector 10, thereby ensuring that the solder mark 11 formed after welding the terminal post to the current collector 10 will not be located at the edge of the current collector 10. This effectively ensures the stability of the connection between the terminal post and the current collector 10, and thus guarantees the performance of the secondary battery.

[0028] Optionally, the shortest distance from any point on the solder mark 11 to the periphery of the protective layer 20 is greater than or equal to 2.5 mm. This setting effectively ensures the coverage of the solder mark 11 by the protective layer 20, thereby effectively preventing the solder mark 11 from contacting the electrolyte and thus preventing the solder mark 11 from turning black.

[0029] Optionally, the solder mark 11 can be circular or polygonal, and it can also be linear. Of course, the specific shape of the solder mark 11 in this application can be adapted to meet actual design requirements.

[0030] Specifically, the protective layer 20 consists of a base film and an adhesive coated on the base film. The protective layer 20 is adhered to the current collector 10 by the adhesive, or in other words, the protective layer 20 is an adhesive tape. In the prior art, although there are methods to protect the solder mark 11 using a dispensing process—that is, using a dispensing mechanism to spray hot melt adhesive onto the solder mark 11, allowing it to cure quickly and thus isolate the electrolyte, thereby preventing blackening—this method does effectively solve the blackening problem of the solder mark 11. However, it requires additional dispensing equipment, and the hot melt adhesive often needs to be above 100°C, resulting in high energy consumption and adhesive costs. Furthermore, the time required for the adhesive to solidify affects production capacity. Therefore, in this application, using adhesive tape to cover and protect the solder mark 11 effectively reduces production costs and significantly improves the production efficiency of secondary batteries.

[0031] Optionally, the thickness of the protective layer 20 is greater than or equal to 50 μm, and the thickness of the adhesive is greater than or equal to 25 μm. Of course, the specific thicknesses of the protective layer and the adhesive can be adjusted adaptively according to actual design requirements.

[0032] Optionally, the base film is made of polyimide or polyethylene terephthalate. The adhesive is acrylate.

[0033] Optionally, the tape is PI (polyimide) tape or PET (polyethylene terephthalate) tape. Furthermore, the adhesive coated on the tape is acrylate. Simultaneously, the protective layer 20 is adhered to the manifold 10, and the peel force of the protective layer 20 is ≥0.3 N / mm. Of course, in this application, tapes composed of other types of substrates and adhesives can also be selected according to actual usage requirements, as long as the tape has good high-temperature resistance, anti-aging properties, weather resistance, and good thermal stability, good adhesion to polar surfaces, and low adhesion to non-polar surfaces.

[0034] Preferably, the selected floor tape must be able to withstand immersion in the electrolyte at 85°C for 4 hours without delamination or peeling. Furthermore, before immersion in the electrolyte, the tape must have a peel strength ≥0.3 N / mm as measured by the 180° peel strength test method according to GB / T2742-2014.

[0035] It should also be noted that when applying the tape to the current collector 10, the tape can be applied using an adhesive applicator, by adsorbing the tape and applying it perpendicularly to the surface of the solder mark 11, or by applying it from one end of the solder mark 11 to the other end. It is necessary to ensure that the tape is applied flat without wrinkles or curling edges, so as to ensure the performance of the current collector of the secondary battery.

[0036] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:

[0037] 1. Effectively solves the problem of blackening of weld marks formed by welding current collector components and poles in existing technologies;

[0038] 2. Simple structure and stable performance.

[0039] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0042] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A secondary battery, characterized in that, include: The terminal post is used to make electrical connection between the secondary battery and the outside. A current collector (10) is welded to the pole post and has a weld mark (11) formed by welding with the pole post. The weld mark (11) has a preset interval between itself and the periphery of the current collector. A protective layer (20) is disposed on the side of the current collector (10) away from the pole post, and the protective layer (20) at least covers the portion of the current collector (10) having the solder mark (11).

2. The secondary battery according to claim 1, characterized in that, The shortest distance from any point of the solder mark (11) to the periphery of the current collector (10) is greater than or equal to 2.5 mm.

3. The secondary battery according to claim 2, characterized in that, The longest distance from any point of the solder mark (11) to the periphery of the current collector (10) shall not exceed 3.5 mm.

4. The secondary battery according to claim 1, characterized in that, The shortest distance from any point of the solder mark (11) to the periphery of the protective layer (20) is greater than or equal to 2.5 mm.

5. The secondary battery according to claim 1, characterized in that, The protective layer (20) consists of a base film and an adhesive coated on the base film, and the protective layer (20) is attached to the current collector (10) by the adhesive.

6. The secondary battery according to claim 5, characterized in that, The thickness of the protective layer (20) is greater than or equal to 50 μm, wherein the thickness of the adhesive is greater than or equal to 25 μm.

7. The secondary battery according to claim 5, characterized in that, The base film is made of polyimide or polyethylene terephthalate.

8. The secondary battery according to claim 5, characterized in that, The adhesive is acrylate.

9. The secondary battery according to claim 1, characterized in that, The protective layer (20) is attached to the current collecting member (10), and the peel force of the protective layer (20) is ≥0.3N / mm.

10. The secondary battery according to claim 1, characterized in that, The solder mark (11) is circular or polygonal in shape.

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