Tab, pole piece and battery

Abstract

The utility model relates to the technical field of battery manufacturing, and discloses a tab, a pole piece and a battery. The tab comprises a protection sheet, a composite foil material and a collector sheet which are connected in a welding manner, a pre-welding area is formed on the composite foil material, a plurality of holes are formed in the pre-welding area, a plurality of bulges matched with the holes are arranged on the protection sheet, and welding spots of the composite foil material, the protection sheet and the collector sheet at least pass through the axes of part of the holes. The pole piece comprises a pole piece body and two tabs. The battery comprises the pole piece. According to the tab provided by the utility model, the protection sheet, the composite foil and the collector sheet can be directly welded, so that the length of the battery tab is shortened, an electron transmission path is shortened, the overall internal resistance of the battery is reduced, and meanwhile, the manufacturing size of the battery is shortened, or the area of a material area is increased under the condition of the same size; the volume energy density of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery manufacturing, in particular to a pole ear, a pole piece and a battery. Background Art

[0002] The middle of the composite foil structure is a polymer material such as PET, PI or PP, and the upper and lower surfaces are copper / aluminum foil. Composite foil has the advantages of high energy density and high safety. During acupuncture, the PET or PP layer will block the internal short circuit of the metal layer, prevent spontaneous combustion, and improve the safety of the product.

[0003] However, the welding difficulty of composite foil is much more difficult than that of non-composite foil, and it is difficult to ensure the welding effect and conductive effect by direct welding. Therefore, most of the existing technologies adopt the transfer welding method to weld two layers of pure foil on the composite foil as the battery tab, and then weld the welded tab to the current collector to achieve the function of current conduction, and then encapsulate the battery cell with aluminum-plastic film to make a battery structure.

[0004] The pole piece and battery made by this production method increase the transmission path of electrons on the foil, which leads to an increase in the internal resistance of the battery. In addition, the transfer welding position can no longer be welded, so the pole ear will be lengthened, thereby occupying part of the battery space, which cannot effectively utilize the space and reduces the volume energy density of the battery. Utility Model Content

[0005] In order to solve the above technical problems or at least partially solve the above technical problems, the utility model provides a pole ear, a pole piece and a battery.

[0006] The utility model provides a pole ear, comprising a protective sheet, a composite foil and a current collecting sheet connected by welding, a pre-welding area is formed on the composite foil, a plurality of holes are opened on the pre-welding area, a plurality of protrusions matching the holes are provided on the protective sheet, and the welding points of the composite foil, the protective sheet and the current collecting sheet at least pass through part of the axis of the holes.

[0007] Optionally, the plurality of protrusions correspond one-to-one to the plurality of holes; and / or,

[0008] The welding points of the composite foil, the protection sheet and the current collecting sheet pass through the axes of all the holes.

[0009] Optionally, the welding points of the composite foil, the protection sheet and the current collecting sheet pass through the axes of all the holes, and the arrangement of the welding points of the composite foil, the protection sheet and the current collecting sheet is consistent with the arrangement of the holes.

[0010] Optionally, the cross section of the hole is circular or polygonal; and / or,

[0011] The plurality of holes are evenly arranged.

[0012] Optionally, the cross section of the hole is circular, the cross section diameter of the hole is 0.5-10 mm, and the distance between two adjacent holes is 3-10 mm; or,

[0013] The cross section of the hole is square, the side length of the cross section of the hole is 1-5 mm, and the distance between two adjacent holes is 3-10 mm.

[0014] Optionally, the cross-section of the hole is a regular hexagon, and two adjacent holes share part of the hole peripheral wall, so that the plurality of holes form a honeycomb shape.

[0015] Optionally, the composite foil is formed on a pole piece body, and the protection sheet and the current collecting sheet are located on both sides of the composite foil; and / or,

[0016] The size of the protection sheet is larger than that of the composite foil, and the size of the composite foil is larger than that of the current collecting sheet.

[0017] Optionally, the protective sheet is an aluminum sheet, and the thickness of the aluminum sheet is 0.4-1.2 mm; or,

[0018] The protective sheet is a copper sheet, and the thickness of the copper sheet is 0.2-1.0 mm.

[0019] The utility model also provides a pole piece, comprising a pole piece body and the two pole ears above arranged on the pole piece body.

[0020] The utility model also provides a battery, comprising the above-mentioned pole piece.

[0021] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0022] In the pole ear provided by the utility model, a pre-welding area is formed on the composite foil, and a hole is opened in the pre-welding area, and a plurality of protrusions are provided on the protective sheet so that the protrusions can be inserted into the corresponding holes, and the welding points of the composite foil, the protective sheet and the current collecting sheet at least pass through the axis of part of the holes, which can ensure the connection strength and meet the use requirements of the pole ear, so that the protective sheet, the composite foil and the current collecting sheet can be directly welded, thereby shortening the length of the battery pole ear, shortening the transmission path of electrons, reducing the overall internal resistance of the battery, and shortening the manufacturing size of the battery at the same time, or in the case of the same size, increasing the area of ​​the material area and improving the volume energy density of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present utility model, and together with the description, are used to explain the principles of the present utility model.

[0024] In order to more clearly illustrate the implementation mode of the utility model or the technical solution in the prior art, the drawings required for use in the implementation mode or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a schematic diagram of the structure of the pole piece described in the embodiment of the utility model;

[0026] Figure 2 This is a schematic diagram of the structure of the composite foil and the protective sheet when they are matched in the embodiment of the utility model;

[0027] Figure 3 for Figure 2 A partial enlarged view of the middle A;

[0028] Figure 4 This is a schematic diagram of an embodiment of the utility model in which the cross section of the hole is a regular hexagon.

[0029] Description of Reference Numerals

[0030] 1. Protective sheet; 2. Composite foil; 21. Pre-welding area; 211. Holes; 22. First metal layer; 23. Second metal layer; 24. Polymer layer; 3. Current collector; 4. Pole body. DETAILED DESCRIPTION

[0031] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the scheme of the utility model will be further described below. It should be noted that the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

[0032] The following description sets forth many specific details to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; obviously, the implementation methods in the specification are only part of the implementation methods of the present invention, rather than all of the implementation methods.

[0033] Combination Figures 1 to 4 As shown, the tab provided by the embodiment of the utility model comprises a welded protective sheet 1, a composite foil 2 and a current collecting sheet 3. Specifically, the protective sheet 1, the composite foil 2 and the current collecting sheet 3 are welded in sequence so that the protective sheet 1 and the current collecting sheet 3 are located on both sides of the composite foil 2, respectively.

[0034] Combination Figure 2 and Figure 3 As shown, a pre-welding area 21 is formed on the composite foil 2, that is, before welding the composite foil 2 with the protective sheet 1 and the current collecting sheet 3, ultrasonic pre-welding treatment is performed on the position of the pre-welding area 21 of the composite foil 2 to weld the pre-welding area 21 of the composite foil 2 into a tightly connected structure to ensure the structural strength at this position. The area of ​​the pre-welding area 21 can be designed according to actual needs.

[0035] A plurality of holes 211 are provided on the pre-welding area 21, and the shape and size of the holes 211 can also be designed according to actual needs. Here, "multiple" is specially defined, that is, "multiple" can be 1 or 2 or more. A plurality of protrusions matching the holes 211 are provided on the protective sheet 1, and during welding, the protrusions can be inserted into the corresponding holes 211. Among them, the matching here should ensure that the protrusions can be inserted into the holes 211, for example, the outer diameter of the protrusions is smaller than the inner diameter of the holes 211, so that the protrusions and the holes 211 have a clearance fit; for another example, the outer diameter of the protrusions is the same as the inner diameter of the holes 211, or the outer diameter of the protrusions is slightly larger than the inner diameter of the holes 211, so that the protrusions and the holes 211 have an interference fit. It can be seen that the matching method between the protrusions and the holes 211 is not restricted and can be designed according to actual needs.

[0036] The welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 pass through at least part of the axis of the holes 211. Specifically, the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 only pass through part of the axis of the holes 211. Alternatively, the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 pass through the axis of all the holes 211. Alternatively, after the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 pass through the axis of part of the holes 211, they also pass through other corresponding positions of the composite foil 2, the protective sheet 1 and the current collecting sheet 3. Alternatively, after the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 pass through the axis of all the holes 211, they also pass through other corresponding positions of the composite foil 2, the protective sheet 1 and the current collecting sheet 3.

[0037] During welding, laser welding or ultrasonic welding is performed through the side of the protective sheet 1, and the welding point passes through at least part of the axis of the hole 211 to reduce the welding breakdown size and ensure the welding effect. At the same time, the protrusion and the hole 211 are welded together to increase the welding area, thereby ensuring the effective welding of the protective sheet 1 and the current collecting sheet 3 and the welding strength. The metal layer of the composite foil 2 is in a molten state to fill the gap of the hole 211, thereby ensuring the conductivity of the electrode.

[0038] In the pole ear provided by the utility model, a pre-welding area 21 is formed on the composite foil 2, and a hole is opened in the pre-welding area 21 (the welding position of the composite foil 2 is pre-welded and a hole is opened), and a plurality of protrusions are provided on the protective sheet 1 so that the protrusions can be inserted into the corresponding holes 211, and the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 at least pass through the axis of part of the hole 211, which can ensure the connection strength and meet the use requirements of the pole ear, so that the protective sheet 1, the composite foil 2 and the current collecting sheet 3 can be directly welded, thereby shortening the length of the battery pole ear, shortening the transmission path of electrons, reducing the overall internal resistance of the battery, and shortening the manufacturing size of the battery at the same time, or in the case of the same size, increasing the area of ​​the material area and improving the volume energy density of the battery.

[0039] In some embodiments, the composite foil 2 includes a middle polymer layer 24 and a first metal layer 22 and a second metal layer 23 disposed on both sides of the polymer layer 24. The polymer layer 24 may include multiple layers of polymer materials, the polymer material may be PET, PI or PP, etc., the first metal layer 22 may be aluminum foil or copper foil, etc., the second metal layer 23 may also be aluminum foil or copper foil, etc., the first metal layer 22, the second metal layer 23 and the polymer layer 24 are combined together in a composite manner to form the composite foil 2. The number of layers of the polymer material can be designed according to actual needs.

[0040] In some embodiments, the thickness of the composite foil 2 is 6-15 μm. Since polymer components such as PET, PI or PP are added to the composite foil 2, the ductility of the composite foil 2 can be improved, thereby solving the problem of frequent breakage of the composite foil 2 when the thickness is reduced.

[0041] In some embodiments, the polymer layer 24 includes a plurality of PET polymer materials, and the PET polymer materials can effectively isolate short circuits caused by the inside and outside of the product, thereby improving the safety performance of the product.

[0042] In some embodiments, the plurality of protrusions correspond to the plurality of holes 211 one by one. In this design, the number of protrusions is the same as the number of holes 211, and each protrusion corresponds to one hole, so as to avoid the phenomenon of excessive opening of holes and ensure the structural strength of the composite foil 2. The positions corresponding to the protrusions and the holes 211 are welded, and during the welding process, the metal layer of the composite foil 2 is in a molten state to fill the holes 211, which can ensure the connection strength and increase the conductivity of the electrode.

[0043] In some embodiments, the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 pass through the axis of all holes 211. In this design, the welding effect of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 can be ensured. At the same time, all holes 211 are filled with the metal layer of the composite foil 2 in a molten state to ensure the overall conductive performance. On this basis, some welding points do not pass through the axis of the hole 211. In this design, the non-hole 211 axis position of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 can be welded according to actual needs to meet the welding requirements in different situations.

[0044] In some embodiments, the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 pass through the axis of all holes 211, and the arrangement of the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 is consistent with the arrangement of the holes 211. Here, the consistent arrangement means that the welding points of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 correspond to the holes 211 one by one, so that the welding points only pass through the holes. Under this design, the welding effect of the composite foil 2, the protective sheet 1 and the current collecting sheet 3 can be ensured. At the same time, all holes 211 are filled with the metal layer of the composite foil 2 in a molten state to ensure the overall conductive performance. In addition, there is no need to add additional welding points, which minimizes the welding cost and meets the welding requirements of the tabs.

[0045] In some embodiments, the cross section of the hole 211 is circular or polygonal. Specifically, the shape of the hole 211 is not limited and can be designed according to actual needs.

[0046] In some embodiments, the plurality of holes 211 are evenly arranged. The holes 211 are evenly arranged to facilitate the opening of the holes 211, and at the same time, the welding points are evenly arranged to ensure the welding effect of the tab. Here, "evenly arranged" may mean that the plurality of holes 211 are arranged in rows or columns, and the spacing between adjacent holes is equal.

[0047] In some embodiments, the distribution of the plurality of holes 211 may not be regular, that is, a non-uniform arrangement may be adopted to meet welding requirements in different situations.

[0048] In some embodiments, the cross section of the hole 211 is circular, the cross section diameter of the hole 211 is 0.5-10 mm, and the distance between two adjacent holes 211 is 3-10 mm. This design is convenient for opening the hole 211, and accordingly, the protrusion is in an arc structure, which is convenient for the protrusion to be inserted into the hole 211. The opening size of the hole 211 can meet the welding requirements, and the gap between two adjacent holes 211 can ensure the strength requirements of the composite foil 2.

[0049] In some embodiments, the cross section of the hole 211 is square, the side length of the cross section of the hole 211 is 1-5 mm, and the distance between two adjacent holes 211 is 3-10 mm. Specifically, the hole 211 can be a square hole of 1*1-5*5, which can be designed according to actual needs. Accordingly, the protrusion is a columnar structure to increase the welding area, and the gap between two adjacent holes 211 can ensure the strength requirements of the composite foil 2.

[0050] In some embodiments, Figure 4 As shown, the cross section of the hole 211 is a regular hexagon, and two adjacent holes 211 share part of the hole peripheral wall, so that the multiple holes 211 form a honeycomb shape. Here, "hole peripheral wall" refers to the surrounding hole walls that enclose the hole 211. In a regular hexagonal structure, the lengths of the six sides are the same, and the angles between two adjacent sides are the same. In two adjacent regular hexagonal holes 211, one of the sides overlaps, and one of the endpoints of the two overlapping sides is the origin. Since the lengths of the three sides intersecting at the origin are the same, the distances from the origin to the endpoints of the three adjacent sides are the same.

[0051] In this design, multiple holes 211 form a honeycomb structure, and the honeycomb structure has good extensibility in the X and Y directions, and structural stability after extension. In addition, since the holes 211 are filled with metal during the welding process, the conductivity of the pole piece can be improved. The connection position of the connection between the three adjacent holes 211 is the center point, and the distances from the endpoints of the three connecting lines connected to the center point are the same to the center point, that is, the distance of electron transmission is a uniform length, and each point has three adjacent points for electron transmission, thereby achieving stable and consistent conductivity.

[0052] In some embodiments, Figure 1 As shown, the composite foil 2 is formed on the pole piece body 4, and the protective sheet 1 and the current collecting sheet 3 are located on both sides of the composite foil 2. The composite foil 2 can be integrally formed with the pole piece body 4, and the protective sheet 1 and the current collecting sheet 3 are welded on both sides of the composite foil 2.

[0053] In some embodiments, continue to refer to Figure 1 , the size of the protective sheet 1 is larger than the size of the composite foil 2, and the size of the composite foil 2 is larger than the size of the current collecting sheet 3. The size here is the area of ​​the protective sheet 1, the composite foil 2 and the current collecting sheet 3. The current collecting sheet 3 is welded to the composite foil 2 at a position close to the pole piece body 4, and the end of the protective sheet 1 close to the pole piece body 4 is flush with the end of the current collecting sheet 3 close to the pole piece body 4, and the end of the protective sheet 1 extends out of the end of the composite foil 2.

[0054] In some embodiments, the protective sheet 1 is an aluminum sheet, and the thickness of the aluminum sheet is 0.4-1.2 mm. At this time, the tab provided with the aluminum protective sheet 1 is used as the positive electrode of the battery.

[0055] In some embodiments, the protective sheet 1 is a copper sheet, and the thickness of the copper sheet is 0.2-1.0 mm. In this case, the tab provided with the copper protective sheet 1 is used as the negative electrode of the battery.

[0056] Among them, the design of the protection sheet 1 can effectively improve the welding quality and increase the conductive performance.

[0057] In some embodiments, the current collecting sheet 3 is an aluminum sheet with a thickness of 0.3-1.0 mm. The tab provided with the aluminum protective sheet 1 is used as the positive electrode of the battery.

[0058] In some embodiments, the current collecting sheet 3 is a copper sheet with a thickness of 0.3-0.6 mm. The tab provided with the copper protective sheet 1 is used as the negative electrode of the battery.

[0059] The manufacturing process of the tab provided in this application comprises the following steps:

[0060] Step S1, ultrasonic pre-welding treatment is performed on the pre-welding area 21 of the composite foil 2 to weld the pre-welding area 21 of the composite foil 2 into a tightly connected structure, wherein the pre-welding position and the laser drilling position of the hole 211 and the subsequent ultrasonic welding position are the same position, and the area of ​​the weld mark varies according to different design requirements.

[0061] Step S2, laser punching is performed on the composite foil material 2 after ultrasonic welding to obtain a plurality of holes 211, and the size of the laser punching can be 0.5 mm-10 mm.

[0062] Step S3, welding the protective sheet 1 + the composite foil material 2 after laser punching + the current collecting sheet 3 together by ultrasonic welding.

[0063] The welding protrusion of the welding head corresponds to the position of the laser drilling to ensure the firmness and stability of the welding.

[0064] The pole ear obtained by this welding method can reduce the length of the pole ear, thereby improving the volume energy density of the battery and making full use of the effective space of the battery. In addition, the damage to the pole piece caused by the roller welding process in the traditional process of composite foil 2 is reduced, including problems such as pole piece dropout and welding wrinkles.

[0065] The utility model also provides a pole piece, including a pole piece body 4 and the two pole ears arranged on the pole piece body 4, wherein the pole ears include all the technical features of the pole ears, and the two pole ears are used as the positive pole and the negative pole of the pole piece body 4 respectively.

[0066] The utility model also provides a battery, comprising the above-mentioned pole piece, wherein the pole piece includes all the technical features of the above-mentioned pole piece, and further includes all the technical features of the above-mentioned pole lug.

[0067] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0068] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments described herein, but should conform to the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A tab, characterized in that: The invention comprises a protective sheet (1), a composite foil (2) and a current collecting sheet (3) connected by welding, wherein a pre-welding area (21) is formed on the composite foil (2), a plurality of holes (211) are provided on the pre-welding area (21), a plurality of protrusions matching the holes (211) are provided on the protective sheet (1), and the welding points of the composite foil (2), the protective sheet (1) and the current collecting sheet (3) at least pass through a part of the axis of the hole (211).

2. The tab according to claim 1, characterized in that: The plurality of protrusions correspond one-to-one to the plurality of holes (211); and / or, The welding points of the composite foil (2), the protective sheet (1) and the current collecting sheet (3) pass through the axes of all the holes (211).

3. The tab according to claim 1, characterized in that: The welding points of the composite foil (2), the protective sheet (1) and the current collecting sheet (3) pass through the axes of all the holes (211), and the arrangement of the welding points of the composite foil (2), the protective sheet (1) and the current collecting sheet (3) is consistent with the arrangement of the holes (211).

4. The tab according to claim 1, characterized in that: The cross section of the hole (211) is circular or polygonal; and / or, The plurality of holes (211) are evenly arranged.

5. The tab according to claim 1, characterized in that: The cross section of the hole (211) is circular, the cross section diameter of the hole (211) is 0.5-10 mm, and the distance between two adjacent holes (211) is 3-10 mm; or, The cross section of the hole (211) is square, the side length of the cross section of the hole (211) is 1-5 mm, and the distance between two adjacent holes (211) is 3-10 mm.

6. The tab according to claim 1, characterized in that: The cross section of the hole (211) is a regular hexagon, and two adjacent holes (211) share part of the hole peripheral wall, so that the plurality of holes (211) form a honeycomb shape.

7. The tab according to claim 1, characterized in that: The composite foil (2) is formed on the pole piece body (4), and the protection sheet (1) and the current collecting sheet (3) are located on both sides of the composite foil (2); The size of the protection sheet (1) is larger than the size of the composite foil (2), and the size of the composite foil (2) is larger than the size of the current collecting sheet (3).

8. The tab according to claim 1, characterized in that: The protective sheet (1) is an aluminum sheet, and the thickness of the aluminum sheet is 0.4-1.2 mm; or, The protective sheet (1) is a copper sheet, and the thickness of the copper sheet is 0.2-1.0 mm.

9. A pole piece, characterized in that: It comprises a pole piece body (4) and two pole ears as claimed in any one of claims 1 to 8 arranged on the pole piece body (4).

10. A battery, characterized in that: Comprising the pole piece as claimed in claim 9.

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