Lithium battery tab encapsulation structure

Abstract

The utility model belongs to lithium battery pole ear packaging field, concretely, relate to a lithium battery pole ear packaging structure. Two pole ear bodies, pole ear glue, aluminium plastic film body, pole ear body includes flow guide portion, sealant part, connecting portion, a plurality of convex, sealant part is fixedly connected along its length direction one end and flow guide portion, the other end is fixedly connected with connecting portion, convex is fixedly connected with sealant part, and the interval is set between two adjacent convex, flow guide portion and connecting portion interval set up with convex respectively, through setting up a plurality of convex on sealant part, and the interval is set between convex, make the contact area of pole ear body and pole ear glue bigger in the process that sealant part and pole ear glue heat seal, thereby make the heat seal of pole ear body and pole ear glue more firm, thereby solve the problem that the contact area of existing pole ear glue and pole ear is smaller, when pole ear and aluminium plastic film fusion seal under the action of shearing stress possibly produce fatigue microcrack, and gradually expand and lead to the problem of sealing failure.

Description

Technical Field

[0001] This utility model belongs to the field of lithium battery tab packaging, and more specifically, it relates to a lithium battery tab packaging structure. Background Technology

[0002] The tab encapsulation of pouch batteries is a precise, multi-step thermal process. Its core lies in permanently fusing and sealing the tabs and aluminum-plastic film together using heat and pressure via tab adhesive. However, due to the significant difference in thermal expansion coefficients between the metal tabs and the polymer plastic (aluminum-plastic film), and because the bonding surface between the tabs and the tab adhesive is small, the interface between the tabs and the adhesive is subjected to cyclic shear stress during battery charging and discharging, temperature cycling, and use. This stress can easily lead to fatigue microcracks that gradually propagate and cause seal failure. Utility Model Content

[0003] To address the problem that existing electrode tab sealant has a small contact area with the electrode tab, which can lead to fatigue microcracks under shear stress after the electrode tab is fused and sealed with the aluminum-plastic film, and these microcracks can gradually propagate and cause seal failure, this invention provides a lithium battery electrode tab sealing structure, comprising: Two electrode bodies are spaced apart. Each electrode body includes a flow guide, a sealing portion, a connecting portion, and multiple protrusions. One end of the sealing portion is fixedly connected to the flow guide, and the other end is fixedly connected to the connecting portion. The protrusions are fixedly connected to the sealing portion, and adjacent protrusions are spaced apart. The flow guide and the connecting portion are spaced apart from the protrusions, respectively. The tab adhesive is fixedly connected to the surface of the sealing portion; the tab adhesive is fixedly connected to the protrusion; the protrusion covers the tab adhesive. An aluminum-plastic film body; a battery cell is encapsulated within the aluminum-plastic film body; the end of the connecting portion away from the sealing portion is fixedly connected to the battery cell; the aluminum-plastic film body is sealed and pressed against the electrode adhesive along the surface of the electrode adhesive towards the connecting portion; the sealing portion is located outside the aluminum-plastic film body; the edge portion of the aluminum-plastic film body surrounds and seals the battery cell. In some embodiments, the protrusions are uniformly disposed at both ends of the sealing portion along the thickness direction.

[0004] In some embodiments, the tab adhesive body further includes a plurality of partition grooves; the partition grooves are recessed inward from the end face of the connecting portion along the thickness direction of the connecting portion; the partition grooves are spaced apart from one end of the connecting portion near the sealing portion to one end away from the sealing portion.

[0005] In some embodiments, the tab adhesive body further includes a plurality of partition grooves; the partition grooves are recessed inward from the circumference of the connecting portion along the circumference of the connecting portion; the partition grooves are spaced apart from one end of the connecting portion near the sealing portion to one end away from the sealing portion.

[0006] In some embodiments, the thickness of the flow guide is H1 mm, and the maximum distance between the two ends of the sealing portion protruding in the thickness direction of the sealing portion is H2 mm; the thickness direction of the flow guide is the same as the thickness direction of the sealing portion, wherein 0.96 ≤ H2 / H1 ≤ 1.

[0007] In some embodiments, one of the electrode bodies is made of aluminum, and the connecting part of the electrode body is fixedly connected to the positive electrode of the battery cell; the other electrode body is made of nickel-copper composite material, and the connecting part of the electrode body is fixedly connected to the negative electrode of the battery cell.

[0008] To address the problem that existing electrode adhesives have a small contact area with the electrode tabs, which can lead to fatigue microcracks under shear stress after the electrode tabs are fused and sealed with the aluminum-plastic film, and these microcracks gradually propagate and cause seal failure, this invention has the following advantages: By setting multiple protrusions on the sealing part and spacing them between each other, the contact area between the electrode body and the electrode adhesive is increased during the heat sealing process of the sealing part and the electrode adhesive. This makes the heat seal between the electrode body and the electrode adhesive more secure, thus solving the problem that the existing electrode adhesive and electrode have a small contact area, which may cause fatigue microcracks under shear stress after the electrode and aluminum-plastic film are fused and sealed, and gradually expand, leading to seal failure. Attached Figure Description

[0009] Figure 1 A schematic diagram of a lithium battery tab packaging structure; Figure 2 for Figure 1 Cross-sectional view along the AA direction; Figure 3 for Figure 2 A magnified view of a portion of point A in the middle; Figure 4 A perspective view of a lithium battery tab packaging structure; Figure 5 This is a schematic diagram of the three-dimensional structure of the electrode; Figure 6 for Figure 5 A magnified view of a portion of point B in the middle; Figure 7 This is a schematic diagram of the planar structure of the electrode.

[0010] In the diagram: 100 - tab body; 110 - flow guide; 120 - sealing part; 130 - connecting part; 140 - protrusion; 150 - partition groove; 200 - tab adhesive; 300 - aluminum-plastic film body; 400 - battery cell body. Detailed Implementation

[0011] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0012] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0013] This embodiment discloses a lithium battery tab packaging structure, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, it may include: Two electrode bodies 100 are spaced apart. Each electrode body 100 includes a flow guiding portion 110, a sealing portion 120, a connecting portion 130, and a plurality of protrusions 140. One end of the sealing portion 120 is fixedly connected to the flow guiding portion 110 along its length, and the other end is fixedly connected to the connecting portion 130. The protrusions 140 are fixedly connected to the sealing portion 120, and adjacent protrusions 140 are spaced apart. The flow guiding portion 110 and the connecting portion 130 are spaced apart from the protrusions 140, respectively. The tab adhesive 200 is fixedly connected to the surface of the sealing part 120; the tab adhesive 200 is fixedly connected to the protrusion 140; the protrusion 140 is enclosed within the tab adhesive 200; An aluminum-plastic film body 300 is provided; a battery cell is encapsulated within the aluminum-plastic film body 300; the end of the connecting portion 130 away from the sealing portion 120 is fixedly connected to the battery cell; the aluminum-plastic film body 300 is sealed and pressed against the tab adhesive 200 along the surface of the tab adhesive 200 towards the connecting portion 130; the sealing portion 120 is located outside the aluminum-plastic film body 300; the edge portion of the aluminum-plastic film body 300 surrounds and seals the battery cell. In this embodiment, by providing multiple protrusions 140 on the sealing portion 120 and spacing them apart, the contact area between the tab body 100 and the tab adhesive 200 is increased during the heat sealing process of the sealing portion 120 and the tab adhesive 200. This results in a more secure heat seal between the tab body 100 and the tab adhesive 200, thus solving the problem that the existing tab adhesive 200 has a small contact area with the tab, which may cause fatigue microcracks under shear stress after the tab is fused and sealed with the aluminum-plastic film, and these cracks may gradually expand, leading to seal failure. In this embodiment, the tab adhesive 200 is uniformly coated on the surface of the connecting portion 130. The tab adhesive 200 fully contacts the protrusion 140 and also covers the protrusion 140. The material of the tab adhesive 200 can be polypropylene or its modified compound. In this embodiment, the aluminum-plastic film body 300 is a conventional material used for lithium battery encapsulation. When the tab adhesive 200 (PP-based) and the inner layer (CPP) of the aluminum-plastic film body 300 are heat-sealed, since they are homogeneous materials, they will diffuse and interweave with each other after melting. After cooling, they can form the strongest "eutectic" interface, thereby achieving a more solid seal. In this embodiment, the protrusion 140 can also be formed into various shapes by embossing.

[0014] In some embodiments of this utility model, such as Figure 6 As shown, the protrusions 140 are evenly distributed at both ends of the sealing portion 120 along the thickness direction.

[0015] In this embodiment, by uniformly distributing the protrusions 140 at both ends of the sealing portion 120 along the thickness direction, the sealing portion 120 can form a relatively uniform adhesion force with the aluminum-plastic film at both ends along its thickness direction, thereby making the sealing portion 120 less prone to deformation.

[0016] In some embodiments, such as Figure 5 , Figure 6 As shown, the tab adhesive 200 body also includes a plurality of partition grooves 150; the partition grooves 150 are recessed inward from the end face of the connecting portion 130 along the thickness direction of the connecting portion 130; the partition grooves 150 are spaced apart from one end of the connecting portion 130 near the sealing portion 120 to one end away from the sealing portion 120; in some cases, the tab adhesive 200 body also includes a plurality of partition grooves 150; the partition grooves 150 are recessed inward from the circumferential direction of the connecting portion 130 along the circumferential direction of the connecting portion 130; the partition grooves 150 are spaced apart from one end of the connecting portion 130 near the sealing portion 120 to one end away from the sealing portion 120.

[0017] In this embodiment, in some cases, during long-term use of lithium batteries, the electrolyte (especially the solvent and lithium salt decomposition products, such as HF acid) also has strong permeability and chemical corrosivity. They may slowly migrate and permeate along the polymer interface between CPP and tab adhesive 200. By setting multiple baffle grooves 150, a straight permeation path can be transformed into an extremely tortuous and long path. This will greatly delay the time it takes for the electrolyte to permeate to the outside of the battery or corrode the tab body 100 guide section 110, thereby further improving the battery's lifespan and reliability.

[0018] In some embodiments of this utility model, such as Figure 7 As shown, the thickness of the flow guide 110 is H1mm, and the maximum distance between the two protrusions 140 at both ends of the sealing part 120 along its thickness direction is H2mm; the thickness direction of the flow guide 110 is the same as the thickness direction of the sealing part 120, where 0.96≤H2 / H1≤1.

[0019] In this embodiment, the ratio of H2 to H1 is set to 0.96≤H2 / H1≤1, which makes the thickness of H2 close to or equal to the thickness of H1. This allows the aluminum-plastic film body 300 to avoid bulging at the sealing part 120 after heat sealing with the sealing part 120, thus preventing gaps between the aluminum-plastic film body 300 and the sealing part 120.

[0020] In some embodiments of this utility model, one of the electrode bodies 100 is made of aluminum, and the connecting portion 130 of the electrode body 100 is fixedly connected to the positive electrode of the battery cell (e.g., by welding); the other electrode body 100 is made of nickel-copper composite material, and the connecting portion 130 of the electrode body 100 is fixedly connected to the negative electrode of the battery cell (e.g., by welding).

[0021] The working principle of this utility model is as follows: According to the predetermined procedure, the tab adhesive 200 is evenly applied to the sealing part 120, and the aluminum-plastic film body 300 is heat-pressed by a related hot pressing device, so that the aluminum-plastic film body 300 and the sealing part 120 are heat-sealed.

[0022] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of this disclosure.

Claims

1. A lithium battery tab packaging structure, characterized in that, include: Two electrode bodies are spaced apart. Each electrode body includes a flow guide, a sealing portion, a connecting portion, and multiple protrusions. One end of the sealing portion is fixedly connected to the flow guide, and the other end is fixedly connected to the connecting portion. The protrusions are fixedly connected to the sealing portion, and adjacent protrusions are spaced apart. The flow guide and the connecting portion are spaced apart from the protrusions, respectively. The tab adhesive is fixedly connected to the surface of the sealing portion; the tab adhesive is fixedly connected to the protrusion; the protrusion covers the tab adhesive. An aluminum-plastic film body; a battery cell is encapsulated within the aluminum-plastic film body; the end of the connecting portion away from the sealing portion is fixedly connected to the battery cell; the aluminum-plastic film body is sealed and pressed against the electrode adhesive along the surface of the electrode adhesive towards the connecting portion; the sealing portion is located outside the aluminum-plastic film body; the edge portion of the aluminum-plastic film body surrounds and seals the battery cell.

2. The lithium battery tab packaging structure according to claim 1, characterized in that, The protrusions are evenly distributed at both ends of the sealing portion along the thickness direction.

3. The lithium battery tab packaging structure according to claim 1, characterized in that, The tab adhesive body also includes a plurality of partition grooves; the partition grooves are recessed inward from the end face of the connecting part along the thickness direction of the connecting part; the partition grooves are spaced apart from one end of the connecting part near the sealing part to the end away from the sealing part.

4. The lithium battery tab packaging structure according to claim 1, characterized in that, The tab adhesive body also includes a plurality of partition grooves; the partition grooves are recessed inward from the circumference of the connecting portion along the circumference of the connecting portion; the partition grooves are spaced apart from one end of the connecting portion near the sealing portion to the end away from the sealing portion.

5. A lithium battery tab packaging structure according to claim 1, characterized in that, The thickness of the flow guide is H1mm, and the maximum distance between the two ends of the sealing part protruding along its thickness direction in the thickness direction of the sealing part is H2mm; the thickness direction of the flow guide is the same as the thickness direction of the sealing part, where 0.96≤H2 / H1≤1.

6. The lithium battery tab packaging structure according to claim 1, characterized in that, One of the electrode bodies is made of aluminum, and the connecting part of the electrode body is fixedly connected to the positive electrode of the battery cell; the other electrode body is made of nickel-copper composite material, and the connecting part of the electrode body is fixedly connected to the negative electrode of the battery cell.

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