Battery pole piece and battery

Abstract

The utility model discloses a battery pole piece and discloses a battery with the battery pole piece, the battery pole piece comprises a current collector, a first active material layer, a thickening layer, a second active material layer and a tab, the current collector is provided with a first surface and a second surface which are opposite along the thickness direction of the current collector, the first surface is provided with a first area, and the second surface is provided with a second area. The first surface is provided with a first area, the second surface is provided with a second area, the first area and the second area are oppositely arranged, the first active material layer is arranged on the first surface, the first area is not provided with the first active material layer, the thickening layer is arranged on the second area, the second active material layer is arranged on the second surface, and the second area is covered with the second active material layer; the thickening layer is located between the second active material layer and the second region, the tab is arranged in the first region, and the thickening layer and the tab are oppositely arranged, so that the area of the second active material layer can be increased to improve the energy density of the battery, the defects of pseudo soldering and perforation of the battery pole piece can be effectively avoided, and the yield of the battery pole piece can be improved.

Description

Technical Field

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

[0002] In recent years, with the development of lithium battery technology, lithium-ion batteries have become widely used due to their high operating voltage, long cycle life, and lack of memory effect. The center-tab structure is a type of battery cell structure. Compared to conventional structures, batteries with the center-tab structure, all other factors remaining unchanged, have lower internal resistance and better high-rate discharge performance.

[0003] When the tab is located in the middle of the current collector in a pole piece, blank areas are required on both sides of the current collector's middle to facilitate welding the tab. Because the blank areas occupy a certain amount of space, they cannot be used for coating active material, resulting in low energy density of the battery. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a battery pole piece that can improve the energy density of the battery.

[0005] The utility model also provides a battery having the battery pole piece.

[0006] According to the battery electrode of the embodiment of the first aspect of the present invention, the current collector includes a first active material layer, a thickened layer, a second active material layer and a tab. Along the thickness direction of the current collector, the current collector has a first surface and a second surface relative to each other, the first surface is provided with a first area, the second surface is provided with a second area, the first area and the second area are arranged opposite to each other, the first active material layer is provided on the first surface, the first area is not provided with the first active material layer, the thickened layer is provided in the second area, the second active material layer is provided on the second surface, and the second active material layer covers the second area, the thickened layer is located between the second active material layer and the second area, the tab is provided in the first area, and the thickened layer is arranged opposite to the tab.

[0007] The battery pole piece according to the first embodiment of the present utility model has at least the following beneficial effects:

[0008] When laser welding the tabs, the tabs, current collector, thickened layer and second active material layer are stacked in sequence. The heat generated by the laser beam is transferred to the thickened layer through the current collector to fuse the tabs, current collector and thickened layer. By arranging the thickened layer between the second active material layer and the current collector, on the one hand, the area of the second active material layer can be increased to improve the energy density of the battery. On the other hand, the operator can increase the power of the laser system so that the laser beam can weld through the current collector, but the laser beam does not weld through the thickened layer. When the tabs are fully fused with the current collector, the battery pole piece does not produce a perforation defect, which can effectively avoid the battery pole piece from having cold welding and perforation defects and can improve the yield rate of the battery pole piece.

[0009] According to some embodiments of the present invention, the projected area of the thickened layer in the second region is larger than the area of the first region of the tab.

[0010] According to some embodiments of the present invention, the thickened layer includes metal powder and inorganic powder, and the material of the inorganic powder is one of aluminum oxide, magnesium oxide and barium oxide.

[0011] According to some embodiments of the present invention, the material of the metal powder is the same as the material of the current collector.

[0012] According to some embodiments of the present invention, the thickened layer includes a metal layer and an inorganic layer, the metal layer is located between the current collector and the inorganic layer, and the material of the inorganic layer is one of aluminum oxide, magnesium oxide and barium oxide.

[0013] According to some embodiments of the present invention, the thickness of the thickened layer is D, and D satisfies: 2um≤D≤20um.

[0014] According to some embodiments of the present invention, the thickened layer is bonded to the second region.

[0015] According to some embodiments of the present invention, two first regions are configured, the two first regions are spaced apart from the current collector, and two thickened layers are correspondingly configured.

[0016] According to some embodiments of the present invention, a third area is provided at the end of the first surface, a fourth area is correspondingly provided at the end of the second surface, two of the pole ears and the thickened layer are correspondingly configured, one of the two pole ears is provided in the first area, and the other is provided in the third area, and one of the two thickened layers is provided in the second area, and the other is provided in the fourth area.

[0017] According to the second aspect of the present invention, the battery comprises a shell and a battery cell, wherein the battery cell comprises a battery cell unit, and the battery cell unit comprises a positive electrode sheet, a separator, a negative electrode sheet and a separator stacked in sequence, and the battery cell unit is wound to form the battery cell, and the battery cell is installed in the shell, and the positive electrode sheet and / or the negative electrode sheet are the battery sheets described in the above embodiments.

[0018] The battery according to the second embodiment of the present invention has at least the following beneficial effects:

[0019] When laser welding the tabs, the tabs, current collector, thickened layer and second active material layer are stacked in sequence. The heat generated by the laser beam is transferred to the thickened layer through the current collector to fuse the tabs, current collector and thickened layer. By arranging the thickened layer between the second active material layer and the current collector, on the one hand, the area of the second active material layer can be increased to improve the energy density of the battery. On the other hand, the operator can increase the power of the laser system so that the laser beam can weld through the current collector, but the laser beam does not weld through the thickened layer. When the tabs are fully fused with the current collector, the battery pole piece does not produce a perforation defect, which can effectively avoid the battery pole piece from having cold welding and perforation defects and can improve the yield rate of the battery pole piece.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 A top view of a battery electrode according to a first embodiment of the present invention;

[0023] Figure 2 This is a front view of the battery electrode of the first embodiment of the present utility model;

[0024] Figure 3 A top view of a battery electrode according to a second embodiment of the present invention;

[0025] Figure 4 This is a front view of a battery electrode according to a second embodiment of the present invention;

[0026] Figure 5 A top view of a battery electrode according to a third embodiment of the present invention;

[0027] Figure 6 A front view of a battery electrode according to a third embodiment of the present invention;

[0028] Figure 7 This is a front view of a battery electrode according to a fourth embodiment of the present invention;

[0029] Figure 8 for Figure 7 A partial enlarged view of part A.

[0030] Reference numerals:

[0031] Current collector 100 , first surface 110 , first region 111 , third region 112 , second surface 120 , second region 121 , fourth region 122 , first active material layer 130 , second active material layer 140 , thickening layer 200 , metal layer 210 , inorganic layer 220 , and tab 300 . DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0033] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0034] In the description of this utility model, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0035] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0036] As mentioned above, in the related art, when the tab is located in the middle of the current collector in the electrode sheet, blank areas need to be provided on the surfaces of both sides of the middle of the current collector to facilitate welding of the tab. Since the blank area occupies a certain amount of space, it cannot be used to coat the active material, resulting in a low energy density of the battery. Based on this, the utility model provides a thickened layer in the middle of the side of the current collector away from the tab, and the tab is welded to the thickened layer through the current collector. The thickened layer can be covered by the second active material layer, which can increase the area of the second active material layer and improve the energy density of the battery. On the other hand, when the power of the laser system is too large, although the laser beam can weld through the current collector, the laser beam cannot weld through the thickened layer, so that when the tab is fully fused with the current collector, the battery electrode sheet does not produce perforation defects, which can effectively avoid the occurrence of cold welding and perforation defects in the battery electrode sheet and improve the yield rate of the battery electrode sheet.

[0037] Reference Figure 1 、 Figure 2 According to the battery electrode of the embodiment of the first aspect of the present invention, the battery electrode comprises a current collector 100, a first active material layer 130, a thickened layer 200, a second active material layer 140 and a tab 300. Along the thickness direction of the current collector 100, the current collector 100 has a first surface 110 and a second surface 120 opposite to each other, a first region 111 is provided in the middle of the first surface 110, and a second region 121 is provided in the middle of the second surface 120. Along the thickness direction of the current collector 100, the first region 111 and the second region 121 are arranged opposite to each other, and the first active material layer 130 is provided at the first surface 110. A surface 110, and the first active material layer 130 is not set in the first area 111, the thickened layer 200 is set in the second area 121, the second active material layer 140 is set on the second surface 120, and the second active material layer 140 covers the second area 121, the tab 300 is set in the first area 111, and the tab 300 is partially welded with the thickened layer 200 through the current collector 100, which not only increases the area of the second active material layer 140 to improve the energy density of the battery, but also effectively avoids the occurrence of cold welding and perforation defects in the battery electrode, and can improve the yield rate of the battery electrode.

[0038] Specifically, when laser welding the pole tab 300, the pole tab 300, the current collector 100, the thickened layer 200 and the second active material layer 140 are stacked in sequence. The heat generated by the laser beam is transferred to the thickened layer 200 through the current collector 100 to fuse the pole tab 300, the current collector 100 and the thickened layer 200. By arranging the thickened layer 200 between the second active material layer 140 and the current collector 100, on the one hand, the area of the second active material layer 140 can be increased to improve the energy density of the battery. On the other hand, the operator can increase the power of the laser system so that the laser beam can weld through the current collector 100, but the laser beam does not weld through the thickened layer 200, so that when the pole tab 300 is fully fused with the current collector 100, the battery pole piece does not produce a perforation defect, which can effectively avoid the battery pole piece from having cold welding and perforation defects, and can improve the yield rate of the battery pole piece.

[0039] As another embodiment, the tab 300 may be welded only to the current collector 100 but not to the thickened layer 200. The thickened layer 200 can prevent the current collector 100 from being welded through, thereby improving the yield rate of the battery electrode. This will not be elaborated here.

[0040] It should be noted that the first surface 110 and the second surface 120 are the surfaces with the largest surface areas of the current collector 100 .

[0041] It should be noted that if Figure 2 As shown, the thickness direction of the current collector 100 is Figure 2 In the up-down direction, the first surface 110 is located above the second surface 120 .

[0042] It should be noted that the middle of the current collector 100 may refer to the exact middle of the current collector 100 , or may refer to a position slightly to the left of the middle or slightly to the right of the middle of the current collector 100 , which will not be described in detail here.

[0043] In some embodiments of the present invention, the projected area of the thickened layer 200 in the second region 121 is larger than the projected area of the tab 300 in the first region 111 , which can avoid perforation defects in the battery electrode and improve the yield rate of the battery electrode.

[0044] Specifically, the projection of the thickened layer 200 in the second area 121 covers the projection of the pole tab 300 in the first area 111. During the laser welding of the pole tab 300, it can be ensured that the fusion position of the pole tab 300 and the current collector 100 coincides with the thickened layer 200, so as to avoid perforation defects in the battery electrode and improve the yield rate of the battery electrode.

[0045] It should be noted that if the projection area of the thickened layer 200 in the second region 121 is smaller than the projection area of the tab 300 in the first region 111, the projection of the thickened layer 200 in the second region 121 cannot cover the projection of the tab 300 in the first region 111. When the tab 300 is laser welded, the current collector 100 is likely to be welded through.

[0046] In some embodiments of the present invention, the thickening layer 200 includes metal powder and inorganic powder, and the metal powder and the inorganic powder are mixed to form the thickening layer 200, wherein the inorganic powder is configured to reduce the temperature during welding and transfer it to the second active material layer 140, thereby ensuring that the activity of the second active material layer 140 is not affected by the welding temperature and ensuring the electrochemical capacity of the battery electrode.

[0047] Specifically, metal powder and inorganic powder are stirred and mixed to form a thickened layer 200. Before installing the tab 300, the thickened layer 200 is pre-coated on the second surface 120 by coating. During the coating of the thickened layer 200 and the laser welding of the tab 300, the tab 300, the current collector 100 and the metal powder are fused with each other. The inorganic powder can reduce the temperature during welding and transfer it to the second active material layer 140, thereby ensuring that the activity of the second active material layer 140 is not affected by the welding temperature and ensuring the electrochemical capacity of the battery electrode.

[0048] It should be noted that the material of the inorganic powder can be one of aluminum oxide, magnesium oxide and barium oxide, which will not be described in detail here.

[0049] In some embodiments of the present invention, the material of the metal powder is the same as that of the current collector 100 , which can improve the laser welding effect and thus improve the laser welding quality.

[0050] Specifically, when the battery electrode is configured as a positive electrode, the current collector 100 of the positive electrode is made of aluminum metal. At this time, the material of the metal powder is also aluminum metal. When the battery electrode is configured as a negative electrode, the current collector 100 of the negative electrode is made of copper metal. The material of the metal powder is also copper metal, so that the metal powder in the thickened layer 200 can be fully fused with the current collector 100, which can improve the laser welding effect and thus improve the laser welding quality.

[0051] As another embodiment, refer to Figure 7 、 Figure 8The thickened layer 200 includes a metal layer 210 and an inorganic layer 220. The metal layer 210 is located between the inorganic layer 220 and the current collector 100. One side of the metal layer 210 is connected to the current collector 100, and the other side of the metal layer 210 is connected to the inorganic layer 220. The side of the inorganic layer 220 away from the metal layer 210 is connected to the second active material layer 140. The inorganic layer 220 is configured to reduce the temperature during welding and transfer it to the second active material layer 140, thereby ensuring that the activity of the second active material layer 140 is not affected by the welding temperature and ensuring the electrochemical capacity of the battery electrode.

[0052] It should be noted that the material of the inorganic layer 220 can be one of aluminum oxide, magnesium oxide and barium oxide, which will not be described in detail here.

[0053] It should be noted that the material of the metal layer 210 is the same as that of the current collector 100 , which can improve the laser welding effect and thus improve the laser welding quality.

[0054] In some embodiments of the present invention, the thickness of the thickened layer 200 is D, and D satisfies: 2um≤D≤20um. When D is less than 2μm, the thickness of the thickened layer 200 is too thin. When the pole piece 300 is laser welded, the thickened layer 200 is easily welded through, and perforation defects are easily generated. When D is greater than 20μm, the thickness of the thickened layer 200 is too thick, which easily increases the physical weight of the battery cell, resulting in a decrease in the energy density of the battery. By setting the thickness of the thickened layer 200 to: 2um≤D≤20um, the energy density of the battery can be improved and perforation defects in the battery pole piece can be avoided.

[0055] In some embodiments of the present invention, the thickened layer 200 is bonded to the second region 121 , which can facilitate the installation of the thickened layer 200 and improve the production efficiency of the battery pole pieces.

[0056] Specifically, the thickened layer 200 can be bonded to the second region 121 by an adhesive, and the adhesive can be a PVDF (polyvinylidene fluoride) adhesive, which can facilitate the installation of the thickened layer 200 and improve the production efficiency of the battery electrode.

[0057] It should be noted that PVDF is a high-performance polymer material with excellent chemical resistance, heat resistance and weather resistance, and is widely used in the manufacturing process of batteries such as solar cells and lithium-ion batteries.

[0058] Reference Figure 3 、 Figure 4 In some embodiments of the present invention, two first regions 111 are configured, the two first regions 111 are arranged at intervals, and the two first regions 111 are located in the middle of the current collector 100, and two pole tabs 300 and thickened layers 200 are correspondingly configured, which can be suitable for a double-pole tab 300 type pole piece with the pole tab 300 placed in the middle.

[0059] Specifically, the two first regions 111 are spaced apart along the length direction of the current collector 100 . The first regions 111 , the tabs 300 and the welding auxiliary layer correspond one to one, and are suitable for a bipolar tab 300 type pole piece with a bipolar tab 300 placed in the middle of the bipolar tab 300 .

[0060] Reference Figure 5 、 Figure 6 In some embodiments of the present invention, a third area 112 is provided at the end of the first surface 110, and a fourth area 122 is correspondingly provided at the end of the second surface 120. Two pole tabs 300 and two thickened layers 200 are correspondingly configured, one of the two pole tabs 300 is provided in the first area 111, and the other is provided in the third area 112. One of the two thickened layers 200 is provided in the second area 121, and the other is provided in the fourth area 122, so that one of the two pole tabs 300 is fixed to the middle of the current collector 100, and the other is fixed to the end of the current collector 100, which can be applicable to a double-pole tab 300 type pole piece with a single pole tab 300 placed in the middle.

[0061] Specifically, along the thickness direction of the current collector 100, the first region 111 and the second region 121 are arranged opposite to each other, and the third region 112 and the fourth region 122 are arranged opposite to each other. The first region 111 and the second region 121 are both located in the middle of the current collector 100, and the third region 112 and the fourth region 122 are both located at the end of the current collector 100. One of the two thickened layers 200 is provided in the second region 121, and the other is provided in the fourth region 122, so that one of the two pole ears 300 is fixed to the middle of the current collector 100, and the other is fixed to the end of the current collector 100, which can be used for a double-pole ear 300 type pole piece with a single pole ear 300 placed in the middle.

[0062] Reference Figure 1 、 Figure 2 According to the battery of the embodiment of the second aspect of the present invention, the battery includes a shell and a battery cell, the battery cell includes a battery cell unit, the battery cell unit includes a positive electrode sheet, a diaphragm, a negative electrode sheet and a diaphragm stacked in sequence, the battery cell unit is wound to form a battery cell, and the battery cell is installed in the shell, the positive electrode sheet and / or the negative electrode sheet is the battery sheet of the embodiment of the first aspect of the present invention, which can not only increase the area of the second active material layer 140 to improve the energy density of the battery, but also effectively avoid the battery sheet from having defects such as cold welding and perforation, and can improve the yield rate of the battery sheet.

[0063] Specifically, when laser welding the pole tab 300, the pole tab 300, the current collector 100, the thickened layer 200 and the second active material layer 140 are stacked in sequence, and the heat generated by the laser beam is transferred to the thickened layer 200 through the current collector 100 to fuse the pole tab 300, the current collector 100 and the thickened layer 200. By arranging the thickened layer 200 between the second active material layer 140 and the current collector 100, on the one hand, the area of the second active material layer 140 can be increased to improve the energy density of the battery. On the other hand, the operator can increase the power of the laser system so that the laser beam can weld through the current collector 100, but the laser beam cannot weld through the thickened layer 200. When the pole tab 300 is fully fused with the current collector 100, the battery pole piece does not produce a perforation defect, which can effectively avoid the battery pole piece from having cold welding and perforation defects, and can improve the yield rate of the battery pole piece.

[0064] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The embodiment is described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiment. Various changes can be made within the knowledge of ordinary technicians in the technical field without departing from the present invention.

Claims

1. A battery pole piece, characterized in that: include: A current collector (100), wherein along a thickness direction of the current collector (100), the current collector (100) has a first surface (110) and a second surface (120) opposite to each other, the first surface (110) being provided with a first region (111), the second surface (120) being provided with a second region (121), and the first region (111) and the second region (121) being arranged opposite to each other; A first active material layer (130) is provided on the first surface (110), and the first region (111) is not provided with the first active material layer (130); a thickening layer (200), provided in the second region (121); A second active material layer (140) is provided on the second surface (120), and the second active material layer (140) covers the second region (121), and the thickened layer (200) is located between the second active material layer (140) and the second region (121); The tab (300) is provided in the first region (111), and the thickened layer (200) is arranged opposite to the tab (300).

2. The battery electrode according to claim 1, characterized in that: The projected area of the thickened layer (200) in the second region (121) is larger than the projected area of the tab (300) in the first region (111).

3. The battery electrode according to claim 1, characterized in that: The thickened layer (200) comprises metal powder and inorganic powder, and the material of the inorganic powder is one of aluminum oxide, magnesium oxide and barium oxide.

4. The battery electrode according to claim 3, characterized in that: The material of the metal powder is the same as that of the current collector (100).

5. The battery electrode according to claim 1, characterized in that: The thickened layer (200) comprises a metal layer (210) and an inorganic layer (220), the metal layer (210) is located between the current collector (100) and the inorganic layer (220), and the material of the inorganic layer (220) is one of aluminum oxide, magnesium oxide and barium oxide.

6. The battery electrode according to claim 1, characterized in that: The thickness of the thickened layer (200) is D, and D satisfies: 2um≤D≤20um.

7. The battery electrode according to claim 1, characterized in that: The thickened layer (200) is bonded to the second region (121).

8. The battery electrode according to claim 1, characterized in that: Two first regions (111) are configured, and the two first regions (111) are spaced apart from each other on the current collector (100), and two thickened layers (200) are correspondingly configured.

9. The battery electrode according to claim 1, characterized in that: A third region (112) is provided at the end of the first surface (110), and a fourth region (122) is correspondingly provided at the end of the second surface (120). Two of the pole tabs (300) and the thickened layer (200) are correspondingly configured, one of the two pole tabs (300) is provided in the first region (111), and the other is provided in the third region (112); one of the two thickened layers (200) is provided in the second region (121), and the other is provided in the fourth region (122).

10. A battery, characterized in that: The battery comprises a shell and a battery cell, wherein the battery cell comprises a positive electrode sheet, a separator, and a negative electrode sheet stacked in sequence, and the battery cell is installed in the shell, and the positive electrode sheet and / or the negative electrode sheet are the battery sheets according to any one of claims 1 to 9.

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