Battery pole piece and battery

Abstract

The battery pole piece comprises a current collector, a thickening layer and a tab, the current collector is provided with a first surface and a second surface which are opposite to each other along the thickness direction of the current collector, the first surface is provided with a first area and a second area, the first area is provided with a first active material layer, and the second area is provided with a second active material layer. The second area is configured to be a blank area without the first active material layer, the second area is located at the end of the current collector, the thickening layer is arranged at the position, corresponding to the second area, of the second surface, the tab is arranged in the second area, the tab and the current collector are oppositely arranged, and by arranging the thickening layer, the thickness of the current collector at the corresponding position of the first area can be increased; even if the current collector is welded through by a laser beam, the laser beam does not weld through the thickening layer, so that the defects of pseudo soldering and perforation of the battery pole piece can be 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 batteries, in particular to a battery pole piece and a battery. Background Art

[0002] Laser welding has been widely used in manufacturing, for example in welding automotive parts and metal pipes. However, these applications are typically performed between thicker materials. Battery electrodes generally consist of a current collector and tabs. Because both are made of thin metal foil, laser welding of the tabs can easily lead to problems such as cold welds and perforations, resulting in a low yield rate for battery electrodes. Utility Model Content

[0003] 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 yield rate of the battery pole piece.

[0004] The utility model also provides a battery having the battery pole piece.

[0005] According to the battery pole piece of the embodiment of the first aspect of the present utility model, it includes a current collector, a thickened layer and a pole ear. 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 and a second area, the first area is provided with a first active material layer, the second area is located at the end of the current collector, the thickened layer is provided at a position corresponding to the second area on the second surface, the pole ear is provided in the second area, and the pole ear is arranged opposite to the thickened layer.

[0006] The battery pole piece according to the first embodiment of the present utility model has at least the following beneficial effects:

[0007] Along the length direction of the current collector, the first area and the second area are arranged side by side, and the thickening layer is arranged at a position corresponding to the second area on the second surface. When the pole ear is laser welded, the pole ear, the current collector and the thickening layer are stacked in sequence. When the heat generated by the laser beam is moderate, the pole ear is welded to the current collector, and the heat generated by the laser beam does not melt the thickening layer, so that the thickening layer is not welded to the current collector. When the heat generated by the laser beam is too much, the heat generated by the laser beam is transferred to the thickening layer through the current collector to fuse the pole ear, the current collector and the thickening layer. By setting the thickening layer, 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 thickening layer, so that when the pole ear is 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.

[0008] According to some embodiments of the present invention, the projected area of the thickened layer on the second surface is larger than the projected area of the tab on the second region.

[0009] 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.

[0010] According to some embodiments of the present invention, the material of the metal powder is the same as the material of the current collector.

[0011] 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.

[0012] According to some embodiments of the present invention, the second surface is provided with a third area and a fourth area, the third area is provided with a second active material layer, the thickened layer is provided in the fourth area, and the thickness of the thickened layer is less than or equal to the thickness of the second active material layer.

[0013] According to some embodiments of the present invention, the thickened layer is bonded to the fourth region.

[0014] According to some embodiments of the present invention, the thickness of the thickened layer is D, and D satisfies: 2um≤D≤20um.

[0015] According to some embodiments of the present invention, the first region is configured with two, the two first regions are respectively provided at both ends of the current collector, the pole ear is correspondingly configured with two, and each first region is configured with at least one thickened layer

[0016] According to the second embodiment of the present invention, the battery includes a shell and a battery cell, the battery cell includes a battery cell unit, and the battery cell unit includes a positive electrode plate, a separator and a negative electrode plate stacked in sequence. The battery cell is installed in the shell, and the positive electrode plate and / or the negative electrode plate are the battery plates described in the above embodiments.

[0017] The battery according to the second embodiment of the present invention has at least the following beneficial effects:

[0018] Along the length direction of the current collector, the first area and the second area are arranged side by side, and the thickening layer is arranged at a position corresponding to the second area on the second surface. When the pole ear is laser welded, the pole ear, the current collector and the thickening layer are stacked in sequence. When the heat generated by the laser beam is moderate, the pole ear is welded to the current collector, and the heat generated by the laser beam does not melt the thickening layer, so that the thickening layer is not welded to the current collector. When the heat generated by the laser beam is too much, the heat generated by the laser beam is transferred to the thickening layer through the current collector to fuse the pole ear, the current collector and the thickening layer. By setting the thickening layer, 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 thickening layer, so that when the pole ear is 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.

[0019] 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

[0020] 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:

[0021] Figure 1 A top view of a battery electrode according to a first embodiment of the present invention;

[0022] Figure 2 This is a front view of the battery electrode of the first embodiment of the present utility model;

[0023] Figure 3 A top view of a battery electrode according to a second embodiment of the present invention;

[0024] Figure 4 This is a front view of a battery electrode according to a second embodiment of the present invention;

[0025] Figure 5 A front view of a battery electrode according to a third embodiment of the present invention;

[0026] Figure 6 for Figure 5 A partial enlarged view of part A.

[0027] Reference numerals:

[0028] Current collector 100 , first surface 110 , first region 111 , second region 112 , second surface 120 , third 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

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] As mentioned above, in the related art, the battery pole piece generally includes a current collector and a tab. Since the current collector and the tab are both thin metal foils, when laser welding the tab, if the power of the laser system is low, the weld cannot reach a sufficient temperature, so that the tab and the current collector cannot be fully fused, and the battery pole piece is prone to cold welding defects. If the power of the laser system is high, the laser beam is easy to weld through the current collector, and the battery pole piece is prone to perforation defects, resulting in a low yield rate of the battery pole piece. Based on this, the utility model provides a thickening layer on the side of the current collector away from the tab, and the tab is welded to the thickening layer through the current collector, which can increase the thickness of the current collector at the corresponding position of the first region. When the power of the laser system is too high, although the laser beam can weld through the current collector, the laser beam does not weld through the thickening layer, so that when the tab is fully fused with the current collector, the battery pole piece does not produce a perforation defect, which can effectively avoid cold welding and perforation defects in the battery pole piece and improve the yield rate of the battery pole piece.

[0034] Reference Figure 1 、 Figure 2According to the battery electrode of the embodiment of the first aspect of the present invention, the battery electrode comprises a current collector 100, a thickened layer 200 and a tab 300. Along the thickness direction of the current collector, the current collector 100 has a first surface 110 and a second surface 120 opposite to each other. The first surface 110 and the second surface 120 are the surfaces with the largest surface areas of the current collector 100. The first surface 110 is provided with a first region 111 and a second region 112. The first region 111 is provided with a first active material layer 130. The second region 112 is configured as a blank region where the first active material layer 130 is not provided. The second region 111 is provided with a first active material layer 130. 12 is located at the end of the current collector 100, the thickened layer 200 is arranged at a position of the second surface 120 corresponding to the second area 112, the pole tab 300 is arranged in the second area 112, the pole tab 300 is arranged opposite to the thickened layer 200, and the pole tab 300 is partially welded through the current collector 100 and the thickened layer 200. In this way, when laser welding the pole tab 300, the power of the laser system can be increased so that the laser beam can weld through the current collector 100, but the laser beam does not weld through the thickened layer 200, which can avoid the defects of cold welding and perforation of the battery electrode and can improve the yield rate of the battery electrode.

[0035] Specifically, along the thickness direction of the current collector 100, the first surface 110 and the second surface 120 are arranged opposite to each other, along the length direction of the current collector 100, the first region 111 and the second region 112 are arranged side by side, and the thickening layer 200 is arranged at a position corresponding to the second region 112 on the second surface 120. When the pole tab 300 is laser welded, the pole tab 300, the current collector 100 and the thickening layer 200 are stacked in sequence. When the heat generated by the laser beam is moderate, the current collector 100 is only welded to the pole tab 300, but not to the thickening layer 200. 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 setting the thickened layer 200, 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 the pole tab 300 is fully fused with the current collector 100, and the battery electrode does not produce a perforation defect, which can effectively avoid the battery electrode from having cold welding and perforation defects, and can improve the yield rate of the battery electrode.

[0036] 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.

[0037] It should be noted that the area on the first surface 110 where the first active material layer 130 is provided is the first area 111, and the area on the first surface 110 where the first active material layer 130 is not provided is the second area 112. The edge in the longitudinal direction of the first active material layer 130 is used as the dividing line to separate the first area 111 and the second area 112, which will not be described in detail here.

[0038] 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 .

[0039] In some embodiments of the present invention, the projected area of the thickened layer 200 on the second surface 120 is larger than the projected area of the tab 300 on the second region 112 , which can avoid perforation defects in the battery electrode and improve the yield rate of the battery electrode.

[0040] Specifically, the projection of the thickened layer 200 on the second surface 120 covers the projection of the pole tab 300 on the second area 112. 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.

[0041] It should be noted that if the projection area of the thickened layer 200 on the second surface 120 is smaller than the projection area of the tab 300 on the second region 112, the projection of the thickened layer 200 on the second surface 120 cannot cover the projection of the tab 300 in the second region 112. When the tab 300 is laser welded, the current collector 100 is likely to be welded through.

[0042] Along the width direction of the tab 300 , the width of the tab 300 is smaller than the width of the thickened layer 200 , which can avoid perforation defects in the battery electrode and improve the yield rate of the battery electrode.

[0043] Specifically, when the width of the pole tab 300 is greater than the width of the thickening layer 200, one side of the pole tab 300 in the width direction partially protrudes from one side of the thickening layer 200 in the width direction. During the laser welding of the pole tab 300, the fusion position of the pole tab 300 and the current collector 100 partially protrudes from the thickening layer 200, resulting in a perforation defect in the current collector 100. By setting the width of the pole tab 300 to be greater than the width of the thickening layer 200, it is possible to ensure that one side of the pole tab 300 in the width direction does not protrude from one side of the thickening layer 200 in the width direction, so that the fusion position of the pole tab 300 and the current collector 100 is within the range of the width direction of the thickening layer 200, which can avoid perforation defects in the battery electrode and improve the yield rate of the battery electrode.

[0044] It should be noted that the width direction of the tab 300 refers to the length direction of the current collector 100, that is, Figure 1 Left and right directions shown.

[0045] 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 first active material layer 130, thereby ensuring that the activity of the first active material layer 130 is not affected by the welding temperature and ensuring the electrochemical capacity of the battery electrode.

[0046] 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 first active material layer 130, thereby ensuring that the activity of the first active material layer 130 is not affected by the welding temperature and ensuring the electrochemical capacity of the battery electrode.

[0047] It should be noted that the inorganic powder is made of heat-resistant material. The material of the inorganic powder can be any one of boehmite, aluminum oxide, magnesium oxide and barium oxide. The material of the inorganic powder can also be any combination of boehmite, aluminum oxide, magnesium oxide and barium oxide, which will not be described in detail here.

[0048] 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.

[0049] 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.

[0050] As another embodiment, refer to Figure 5 、 Figure 6The 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.

[0051] 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.

[0052] 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.

[0053] In some embodiments of the present invention, the second surface 120 is provided with a third area 121 and a fourth area 122, the third area 121 is provided with a second active material layer 140, and the thickened layer 200 is provided in the fourth area 122. The thickness of the thickened layer 200 is less than or equal to the thickness of the second active material layer 140, which can avoid the thickened layer 200 from increasing the volume of the battery cell and can improve the energy density of the battery.

[0054] Specifically, when the thickness of the thickened layer 200 is greater than the thickness of the second active material layer 140, there is a gap between the second active material layer 140 and the diaphragm. The accumulation of several gaps will cause the volume of the battery cell to increase, resulting in a decrease in the energy density of the battery; when the thickness of the thickened layer 200 is less than or equal to the thickness of the second active material layer 140, there is no gap between the second active material layer 140 and the diaphragm, which can avoid the thickened layer 200 increasing the volume of the battery cell and improve the energy density of the battery.

[0055] It should be noted that 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.

[0056] In some embodiments of the present invention, the thickened layer 200 is bonded to the fourth region 122 , which can facilitate the installation of the thickened layer 200 and improve the production efficiency of the battery pole pieces.

[0057] Specifically, the thickened layer 200 can be bonded to the fourth region 122 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.

[0058] 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.

[0059] Reference Figure 3 、 Figure 4 In some embodiments of the present invention, two first regions 111 are configured, and the two first regions 111 are respectively arranged at both ends of the current collector 100, and two pole tabs 300 and thickened layers 200 are correspondingly configured, which can be applicable to double-pole tab 300 type pole pieces.

[0060] Specifically, along the length direction of the current collector 100 , the second region 112 is located between the two first regions 111 . The second region 112 , the tab 300 , and the thickened layer 200 correspond one to one, and are applicable to a double-tab 300 type pole piece.

[0061] Reference Figure 1 、 Figure 2 According to the battery of the embodiment of the second aspect of the present invention, it 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 separator and a negative electrode sheet stacked in sequence, the battery cell is installed in the shell, the positive electrode sheet and / or the negative electrode sheet is the battery electrode sheet of the embodiment of the first aspect of the present invention, when laser welding the tab 300, the power of the laser system can be increased so that the laser beam can weld through the current collector 100, but the laser beam does not weld through the thickened layer 200, which can avoid the defects of cold welding and perforation of the battery electrode sheet and can improve the yield rate of the battery electrode sheet.

[0062] Specifically, along the thickness direction of the current collector 100, the first surface 110 and the second surface 120 are arranged opposite to each other, along the length direction of the current collector 100, the first region 111 and the second region 112 are arranged side by side, and the thickening layer 200 is arranged at a position corresponding to the second region 112 on the second surface 120. When the pole tab 300 is laser welded, the pole tab 300, the current collector 100 and the thickening layer 200 are stacked in sequence. When the heat generated by the laser beam is moderate, the current collector 100 is only welded to the pole tab 300, but not to the thickening layer 200. 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 setting the thickened layer 200, 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 the pole tab 300 is fully fused with the current collector 100, and the battery electrode does not produce a perforation defect, which can effectively avoid the battery electrode from having cold welding and perforation defects, and can improve the yield rate of the battery electrode.

[0063] It should be noted that the battery cell may also include multiple battery cell units, each of which includes a positive electrode sheet, a separator, a negative electrode sheet and a separator stacked in sequence. Multiple battery cell units are stacked to form a battery cell, which will not be described in detail here.

[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) is provided with a first region (111) and a second region (112), the first region (111) is provided with a first active material layer (130), and the second region (112) is located at an end of the current collector (100); a thickening layer (200) provided at a position corresponding to the second surface (120) and the second region (112); A tab (300) is provided in the second region (112), and the tab (300) is arranged opposite to the thickened layer (200).

2. The battery electrode according to claim 1, characterized in that: The projected area of the thickened layer (200) on the second surface (120) is larger than the projected area of the tab (300) on the second region (112).

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 second surface (120) is provided with a third region (121) and a fourth region (122), the third region (121) is provided with a second active material layer (140), the thickened layer (200) is provided in the fourth region (122), and the thickness of the thickened layer (200) is less than or equal to the thickness of the second active material layer (140).

7. The battery electrode according to claim 6, characterized in that: The thickened layer (200) is bonded to the fourth region (122).

8. 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.

9. The battery electrode according to claim 1, characterized in that: There are two first regions (111), which are respectively arranged at the two ends of the current collector (100), and two pole tabs (300) are correspondingly arranged. Each first region (111) is configured with at least one thickened layer (200).

10. A battery, characterized in that: The battery cell 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 and a negative electrode sheet stacked in sequence. 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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