A current collector, a battery pole piece and a battery

Abstract

The utility model provides a kind of current collector, battery pole piece and battery, wherein current collector includes coating area and blank area, coating area is used to coat active material coating, at least one side of coating area is provided with blank area, the thickness of blank area is D1 μm, the thickness of coating area is D2 μm, D1 μm>D2 μm.Compared with prior art, the current collector disclosed in the utility model can effectively improve the yield of tab production, which is embodied in the following three aspects:1) can effectively improve the structural strength of blank area, greatly improve the support force on tab;2) can effectively reduce the probability of tab collapse caused by electrode rolling process;3) can effectively reduce the probability of tab folding during lamination or winding.

Description

Technical Field

[0001] This utility model belongs to the field of battery manufacturing technology, and specifically relates to a current collector, battery electrode, and battery. Background Technology

[0002] In the field of new energy power batteries, improving energy density and reducing battery weight are among the core development directions. As a key component of the battery, the thickness of the substrate (current collector) of the battery negative electrode sheet has a direct impact on the battery's energy density and weight. The smaller the thickness of the current collector, the more active material can be accommodated per unit volume, resulting in a higher battery energy density, while the overall weight of the battery can also be reduced.

[0003] Currently, the thickness of the negative electrode sheet in batteries has been reduced to 4.5μm. However, while this excessive reduction in thickness brings advantages in weight reduction, it also raises a series of serious mechanical reliability issues:

[0004] 1) Insufficient support for the tab: The tab is the part that is drawn out from the blank area of ​​the current collector. The reduction in the overall thickness of the current collector directly leads to a decrease in the structural stiffness of the blank area, which weakens the support for the tab.

[0005] 2) Collapse of the tab after rolling: During the rolling process of the electrode sheet, the entire electrode sheet will be subjected to high pressure. The ultra-thin blank area is difficult to resist this pressure, which can easily lead to the collapse of the tab.

[0006] 3) Tab folding during manufacturing: In subsequent battery stacking or winding processes, the tabs are prone to folding, bending and other deformations, which leads to poor subsequent welding processes and seriously reduces production yield. Utility Model Content

[0007] In view of this, the purpose of this utility model is to provide a current collector that can not only effectively improve the support force of the tab, but also reduce the probability of tab collapse after rolling and tab folding during stacking or winding, thereby effectively improving the yield of tab production.

[0008] Another objective of this invention is to provide a battery electrode.

[0009] Another objective of this invention is to provide a battery.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] A current collector includes a coating area and a blank area. The coating area is used to coat an active material coating. At least one side of the coating area is provided with a blank area. The thickness of the blank area is D1μm, and the thickness of the coating area is D2μm, where D1μm > D2μm.

[0012] As can be seen from the above technical solutions, compared with the prior art, the current collector disclosed in this utility model can effectively improve the yield of electrode production, which is reflected in the following three aspects:

[0013] 1) It can effectively improve the structural strength of the blank area and greatly enhance the support for the electrode tab;

[0014] 2) It can effectively reduce the probability of electrode tab collapse caused by the electrode rolling process;

[0015] 3) It can effectively reduce the chance of the tabs folding during stacking or winding. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the current collector disclosed in the first embodiment of this utility model;

[0018] Figure 2 for Figure 1 The main view;

[0019] Figure 3 This is a front view of the current collector disclosed in the second embodiment of the present invention;

[0020] Figure 4 This is a front view of the current collector disclosed in the third embodiment of this utility model.

[0021] Explanation of reference numerals in the attached figures:

[0022] 100 - Current collector, 101 - Coated area, 102 - Blank area. Detailed Implementation

[0023] In view of this, the core of this utility model is to provide a current collector that can not only effectively improve the support force of the tab, but also reduce the probability of tab collapse after rolling and tab folding during stacking or winding, thereby effectively improving the yield of tab production.

[0024] Another key aspect of this invention is that it provides a battery electrode.

[0025] Another core aspect of this invention lies in providing a battery.

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model. Please refer to... Figures 1-4 .

[0027] Please refer to Figure 1 and Figure 2 The current collector 100 disclosed in this embodiment of the present invention includes a coating area 101 and a blank area 102. The coating area 101 is used to coat an active material coating. At least one side of the coating area 101 has a blank area 102. The thickness of the blank area 102 is D1 μm, and the thickness of the coating area 101 is D2 μm, where D1 μm > D2 μm. Compared with the prior art, the current collector 100 disclosed in this embodiment of the present invention can effectively improve the yield of tab production, which is reflected in the following three aspects:

[0028] 1) It can effectively improve the structural strength of the blank area 102 and greatly enhance the support for the electrode tab;

[0029] 2) It can effectively reduce the probability of electrode tab collapse caused by the electrode rolling process;

[0030] 3) It can effectively reduce the chance of the tabs folding during stacking or winding.

[0031] As a further embodiment, in the current collector disclosed in this utility model embodiment, 2≤D1-D≤5, that is, the thickness range of the blank area 102 exceeding the coating area 101 is between 2μm and 5μm. If D1-D2<2, the improvement in tensile strength and bending resistance is not significant enough, and it may not be able to effectively resist the stress during rolling and winding, and there is still a risk of collapse and folding; if D1-D2>5, the step height at the connection between the blank area 102 and the coating area 101 is too large. Since the connection between the blank area 102 and the coating area 101 is a stress concentration point, this position is very prone to cracks due to fatigue during subsequent charge and discharge cycles of the battery; the D1-D2 range setting disclosed in this utility model embodiment can not only effectively improve the support force of the tab, but also reduce the probability of tab collapse after rolling and tab folding during stacking or winding.

[0032] It should be noted that D1 - D2 can be 2, 3, 4 or 5.

[0033] As a further embodiment, the present invention discloses that D1-D2 < 1 / 2 × D2. This range of differences ensures the support strength of the blank area 102 while mitigating production and performance risks caused by excessive thickness differences.

[0034] This embodiment of the invention does not limit the specific thicknesses of D1μm and D2μm. Any structure that meets the requirements of this invention is within the protection scope of this invention.

[0035] As one embodiment, the present invention discloses 4.5μm≤D1μm≤15μm and 2μm≤D2μm≤10μm.

[0036] Those skilled in the art can flexibly and optimally set the thickness of different parts of the current collector 100 according to the specific energy density, power density, safety standards, cost targets and production processes of the product.

[0037] For example, D1μm can be 4.5μm, 5μm, 6μm, 8μm, 10μm or 15μm, etc., and D2μm can be 2μm, 3μm, 4μm, 6μm, 7μm or 10μm, etc.

[0038] The current collector disclosed in this embodiment can be either a positive or negative electrode. Preferably, a negative electrode is used in the design of the current collector. When a negative electrode is used, the current collector dimensions are: 4.5μm ≤ D1μm ≤ 9μm, and 2μm ≤ D2μm ≤ 7μm. For example, D1μm can be 4.5μm, 5μm, 6μm, 7μm, 8μm, or 9μm, and D2μm can be 2μm, 3μm, 4μm, 5μm, 6μm, or 7μm.

[0039] As a further embodiment, the width of the blank area 102 disclosed in this utility model embodiment is W, where 20mm ≤ Wmm ≤ 40mm, and 90 ≤ D1 × W ≤ 600. For example, Wmm can specifically be 20mm, 25mm, 30mm, 35mm, or 40mm, and D1 × W can specifically be 90, 100, 200, 300, 500, or 600. This range setting can effectively ensure that the blank area 102 can withstand mechanical external forces during rolling, stacking, or winding processes, without collapse or folding.

[0040] This embodiment of the utility model does not limit the specific setting of the blank area 102. Any structure that meets the usage requirements of this utility model is within the protection scope of this utility model.

[0041] As an embodiment of this utility model, the blank area 102 disclosed in this embodiment includes at least a first blank area and a second blank area, wherein the first blank area and the second blank area are respectively disposed on both sides of the current collector 100 along the width direction of the current collector 100. The arrangement of the first blank area and the second blank area allows for the creation of multiple tabs after a single coating process by cutting, thereby effectively improving processing efficiency.

[0042] As a further embodiment, the widths of the first and second blank areas disclosed in this embodiment of the invention are equal. This arrangement helps to improve the accuracy and consistency of tab cutting.

[0043] As another specific embodiment of this utility model, the blank area 102 disclosed in this embodiment further includes a third blank area, wherein the third blank area is disposed between the first blank area and the second blank area, and is parallel to the first blank area and the second blank area. This arrangement allows the addition of the third blank area to create multiple blank areas along the width direction of the current collector, thereby further improving the processing efficiency of the electrode tab.

[0044] As a further embodiment, the widths of the first and second blank areas disclosed in this utility model embodiment are both half the width of the third blank area. This setting helps to improve the accuracy and consistency of the tab cutting.

[0045] Of course, the blank area 102 disclosed in this embodiment of the present invention may also include a fourth blank area, a fifth blank area, a sixth blank area, etc.

[0046] This embodiment of the utility model does not limit the specific structural design of the blank area 102. Any structure that meets the requirements of this utility model is within the protection scope of this utility model.

[0047] For the first embodiment of this utility model, please refer to the following: Figure 1 and Figure 2 In this embodiment of the invention, a transition step is formed at the junction of the blank area 102 and the coating area 101, wherein the sidewall of the transition step is perpendicular to the plane of the current collector 100. This structural arrangement of the blank area 102 can provide strong resistance to bending in order to prevent tab collapse.

[0048] As a second embodiment of this utility model, the current collector 100 disclosed in this embodiment further includes a transition region, wherein the transition region is disposed at the junction of the coating area 101 and the blank area 102. The provision of this transition region can form a gradient buffer zone between the coating area 101 and the blank area 102, thereby effectively dispersing and absorbing the mechanical stress and thermal stress generated in the electrode sheet rolling process.

[0049] As a further embodiment, the transition region disclosed in this utility model embodiment has a transition surface, wherein the length of the transition surface along the width direction of the current collector 100 is Hmm, and 3mm≤Hmm≤6mm. For example, Hmm can specifically be 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or 6mm. This range not only avoids excessively encroaching on the effective coating area of ​​the coating region 101, but also achieves effective support for the electrode tab.

[0050] This utility model embodiment does not specifically limit the specific structure of the transition surface. Any structure that meets the usage requirements of this utility model is within the protection scope of this utility model.

[0051] As a second embodiment of this utility model, please refer to the following for details. Figure 3 The transition surface disclosed in this embodiment of the utility model is an arc surface. The smooth arc allows for a continuous and smooth transition of stress.

[0052] As a further embodiment, the radius of curvature of the arc surface disclosed in this utility model embodiment is Rmm, where 3mm ≤ Rmm ≤ 12mm. For example, Rmm can specifically be 3mm, 5mm, 8mm, 11mm, or 12mm. This setting ensures that the arc surface has sufficient curvature while preventing the arc surface from being too flat and occupying too much space in the coating area 101.

[0053] As a third specific embodiment of this utility model, please refer to Figure 4 The transition surface disclosed in this embodiment of the invention is an inclined surface. The inclined surface also provides a relatively smooth stress buffer zone, thereby effectively dispersing the stress generated on the electrode sheet during the rolling process.

[0054] As a further embodiment, the angle between the inclined plane and the plane of the current collector 100 disclosed in this embodiment of the present invention is a°, wherein 30°≤a°≤45°. For example, a° can specifically be 30°, 32°, 35°, 38°, 40° or 45°. This setting can effectively ensure that the inclined plane disperses stress and prevents coating cracking, while also avoiding the transition area from occupying too much space due to being too gentle.

[0055] It should be noted that, in the current collector disclosed in this embodiment of the present invention, after the coating area 101 is coated with an active material coating, the maximum height of the active material coating extending beyond the blank area 102 is 250 μm, preferably between 60 μm and 250 μm.

[0056] Typically, current collectors are coated on both sides. The active material coating disclosed in this embodiment of the invention is a single-layer coating with a thickness ranging from 210μm to 215μm. When a negative electrode sheet is used for the current collector design, the thickness of the active material ranges from 60μm to 100μm.

[0057] It should be noted that the thickness range of the active material layer disclosed in the embodiments of this utility model refers to the measurement structure after coating, not the measurement structure after rolling.

[0058] A portion of the active material layer is coated on the blank area 102, and the width of the active material layer on the blank area 102 is less than or equal to 3 mm.

[0059] This utility model embodiment also discloses a battery electrode, including a current collector 100 as disclosed in any of the above embodiments.

[0060] Since the battery electrode uses the current collector 100 disclosed in the present invention, the battery electrode also has the technical advantages of the current collector 100 disclosed in the present invention, and the present invention will not elaborate on these advantages further.

[0061] This utility model embodiment also discloses a battery, including battery electrodes as disclosed in any of the above embodiments.

[0062] Since the battery uses the battery electrode sheet disclosed in the present utility model embodiment, the battery also has the technical advantages of the battery electrode sheet disclosed in the present utility model embodiment, and the present utility model embodiment will not elaborate on these advantages one by one.

[0063] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A current collector, characterized in that, It includes a coating area and a blank area. The coating area is used to coat an active material coating. At least one side of the coating area is provided with a blank area. The thickness of the blank area is D1μm and the thickness of the coating area is D2μm, where D1μm>D2μm.

2. The current collector according to claim 1, characterized in that, 2≤D1 -D2≤5.

3. The current collector according to claim 1, characterized in that, D1 - D2 < 1 / 2 × D2.

4. The current collector according to claim 1, characterized in that, 4.5μm≤D1μm≤15μm, 2μm≤D2μm≤10μm.

5. The current collector according to claim 1, characterized in that, The width of the blank area is W, 20mm≤Wmm≤40mm, 90≤D1×W≤600.

6. The current collector according to claim 1, characterized in that, The blank area includes at least a first blank area and a second blank area, which are respectively disposed on both sides of the collector along the width direction of the collector.

7. The current collector according to claim 6, characterized in that, The widths of the first blank area and the second blank area are equal.

8. The current collector according to claim 6, characterized in that, The blank area also includes a third blank area, which is located between the first blank area and the second blank area and is parallel to the first blank area and the second blank area.

9. The current collector according to claim 8, characterized in that, The widths of the first and second blank areas are both half the width of the third blank area.

10. The current collector according to claim 1, characterized in that, It also includes a transition area, which is located at the boundary between the coated area and the blank area.

11. The current collector according to claim 10, characterized in that, The transition region has a transition surface, the length of which along the width direction of the current collector is H mm, where 3 mm ≤ H mm ≤ 6 mm.

12. The current collector according to claim 11, characterized in that, The transition surface is an arc surface.

13. The current collector according to claim 12, characterized in that, The radius of curvature of the arc surface is Rmm, where 3mm ≤ Rmm ≤ 12mm.

14. The current collector according to claim 11, characterized in that, The transition surface is an inclined plane.

15. The current collector according to claim 14, characterized in that, The angle between the inclined plane and the plane of the current collector is a°, where 30°≤a°≤45°.

16. A battery electrode, characterized in that, Includes the current collector as described in any one of claims 1-15.

17. A battery, characterized in that, Includes the battery electrode as described in claim 16.

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