Battery pole piece

Abstract

This application relates to the technical field of batteries, and more particularly to a battery pole piece comprising a pole piece body and a tab, the pole piece body including a current collector and a coating applied to the surface of the current collector, the pole piece body having a slot area and a thinned area on its surface, the current collector exposed on the surface of the slot area of ​​the pole piece body and welded to the end of the tab, and the coating exposed on the surface of the thinned area of ​​the pole piece body and adjacent to the tab. By optimizing the pole piece structure, this application simplifies the production process, avoids battery safety issues, and helps improve battery quality. Furthermore, this application discloses a method for manufacturing battery pole pieces.

Description

[Technical Field]

[0001] The present application relates to the technical field of batteries, and more particularly to battery pole pieces and methods of manufacturing the same. [Background technology]

[0002] In the current mobile phone consumer market, in order to occupy a certain market share and have sufficient product competitiveness, products with fast charging, high energy density, high safety and long cycle life are becoming mainstream.

[0003] In terms of structure, the mainstream adopts a center-positioned tab structure. In contrast to the current center-positioned structure, conventional technologies primarily pre-install slots for welding the tabs before cutting, and then die-cut the scrap material facing the tabs in the slots during the winding process after cutting. However, this requires additional equipment for the die-cutting workstation, increases equipment costs, increases the frequency of tape breakage during the process, reduces winding efficiency, and introduces pole powder generated by the die-cutting, which falls into the cell and affects performance such as the K value. Another approach is to cut the tape in the slot area, leaving some slots in advance where the tabs of adjacent pole pieces face opposite each other. However, the slots that cut the non-welded areas must be treated to prevent the aluminum foil in the slots facing the negative electrode from directly contacting the anode if the diaphragm is punctured, posing a security risk of a short circuit. Summary of the Invention

[0004] The first objective of the present application is to provide a battery pole piece that can simplify the production process, avoid the occurrence of battery safety issues, and help improve the quality of batteries by optimizing the pole piece structure to address the problems of the prior art.

[0005] To achieve the above object, the present application adopts the following technical solution. A battery pole piece comprising a pole piece body and a tab, the pole piece body comprising a current collector and a coating applied to the surface of the current collector, the surface of the pole piece body having a slot area and a thinned area, the current collector exposed on the surface of the slot area of ​​the pole piece body and welded to the end of the tab, the coating exposed on the surface of the thinned area of ​​the pole piece body and adjacent to the tab.

[0006] Preferably, the thinned area of ​​the pole piece body is located between an edge of the slot area and an edge of the pole piece body.

[0007] Preferably, in the width direction Y of the pole piece body, the distance W between the edge of the slot area and the edge of the pole piece body is smaller than the width L of the thinned area, but 0 <W≦8mmである。

[0008] Preferably, the coating located in the thinned area has a thinned portion formed therein, the tab is adjacent to the thinned portion, and the thickness h of the thinned portion is 10 to 50 μm.

[0009] Preferably, the thickness H of the coating located in the thinned area before thinning is 20 to 100 μm.

[0010] Preferably, the thinned thickness h1 of the coating located in the thinned area is 10-80 um.

[0011] Preferably, the coating is a single layer or a multi-layer structure.

[0012] Preferably, the coating includes, in its thickness direction, at least one of an active material layer, a security coating, a carbon coating, and an insulating coating.

[0013] Preferably, the coating located in the slot area has a slot formed therein, the slot including a bottom and a side wall, the side wall extending upward from the bottom, the bottom being a current collector exposed on the surface of the pole piece body, and the coating surrounding the bottom to form the side wall.

[0014] The second object of this application is to applying a coating slurry to a current collector; forming the slot by scraping or laser cleaning the coating in the slot area; forming a thinned portion by thinning the coating in the thinned area; The pole pieces are washed, roll pressed, and cut into pieces in order. welding an end of the tab to the slot so that a portion of the tab is adjacent to the thinned portion; The present invention provides a method for manufacturing a battery pole piece, including:

[0015] The beneficial effects of the present application are as follows: By thinning the coating located in the thinned area of ​​the pole piece body, i.e., by thinning the coating at the position facing the tab, there is no need to die-cut the slot or cut into the slot area after cutting, which not only simplifies the production process but also avoids battery safety issues that may occur during the process, thereby improving battery manufacturing efficiency and yield rate; furthermore, a slot area is provided on the surface of the pole piece body, allowing the end of the tab to be welded to the current collector exposed on the surface of the slot area, and preventing the tab from being close to the top surface of the coating in the thinned area, thereby avoiding an impact on the overall thickness of the cell; by optimizing the pole piece structure, the present application simplifies the production process, avoids battery safety issues, and helps improve battery quality. [Brief explanation of the drawings]

[0016] The features, advantages, and technical effects of exemplary embodiments of the present application are described below with reference to the drawings. [Figure 1] FIG. 1 is a first structural schematic diagram of a pole piece body according to the present application. [Figure 2] FIG. 1 is a first schematic diagram of a pole piece body according to the present application before being thinned. [Figure 3] FIG. 2 is a second structural schematic diagram of the pole piece body according to the present application. [Figure 4] FIG. 10 is a second schematic diagram of the pole piece body according to the present application before thinning. [Figure 5] FIG. 2 is a schematic diagram of a wide pole piece according to the present application. [Figure 6] FIG. 10 is a schematic diagram of the wide pole piece according to the present application after cutting. [Figure 7] FIG. 1 is a schematic diagram of laser cleaning of a pole piece according to the present application. [Figure 8] 1 is a schematic diagram illustrating the operation of a laser emitter according to the present application; [Figure 9] 1 is a schematic diagram of a blade treatment according to the present application. DETAILED DESCRIPTION OF THE INVENTION

[0017] The specification and claims use several terms to refer to specific assemblies. Those skilled in the art will understand that hardware manufacturers may refer to the same assembly by different nouns. The specification and claims do not distinguish between assemblies based on differences in name, but rather use the functional differences between assemblies as the basis for distinction. The term "including" used throughout the specification and claims is an open term and should be interpreted as "including, but not limited to." The term "generally" means within an acceptable margin of error, allowing a person skilled in the art to solve a technical problem and achieve a fundamental technical effect within a certain margin of error.

[0018] Furthermore, terms such as "first," "second," etc. are used merely for descriptive purposes and should not be understood as denoting or implying relative importance.

[0019] In this application, unless otherwise clearly defined or limited, the terms "attach," "couple," "connect," "fix," etc. should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0020] The present application will be described in more detail below in conjunction with FIGS. 1 to 9, but is not limited thereto.

[0021] First embodiment The battery pole piece comprises a pole piece body 1 and a tab 2, the pole piece body 1 comprising a current collector 11 and a coating 12 applied to the surface of the current collector 11, the surface of the pole piece body 1 having a slot area 3 and a thinned area 4, the current collector 11 being exposed on the surface of the slot area 3 of the pole piece body 1 and welded to the end of the tab 2, the coating 12 being exposed on the surface of the thinned area 4 of the pole piece body 1 and being adjacent to the tab 2.

[0022] The conventional structure requires additional equipment for the die-cutting workstation, which increases equipment costs, increases the frequency of tape breakage during the process, reduces winding efficiency, and introduces pole powder generated by the die-cutting process, which falls into the cell and affects performance such as the K value, resulting in a series of problems. It is necessary to process a slot to cut out the non-welded area, which would cause the anode to come into direct contact with the aluminum foil when the diaphragm is broken, resulting in a security risk of a short circuit. Therefore, by thinning the coating 12 located in the thinned area 4 of the pole piece body 1, i.e., the coating 12 facing the tab 2, it is not necessary to die-cut the slot or cut out the slot area after cutting out, which not only simplifies the production process but also avoids battery safety issues that may occur in the above process, thereby improving the manufacturing efficiency and yield rate of the battery. Furthermore, the slot area 3 is provided on the surface of the pole piece body 1, and the end of the tab 2 can be welded to the current collector 11 exposed on the surface of the slot area 3. Furthermore, the tab 2 is close to the upper surface of the coating 12 in the thinned area 4, which avoids affecting the overall thickness of the cell.

[0023] In the battery pole piece according to the present application, the thinned area 4 of the pole piece body 1 is located between the edge of the slot area 3 and the edge of the pole piece body 1. Specifically, the shape of the slot area 3 is rectangular, and the slot area 3 is close to one edge of the pole piece body 1 in the width direction Y, and the area between the slot area 3 and the edge of the pole piece body 1 can be understood as the thinned area 4, which is the end of the slot in the direction in which the tab 2 protrudes, i.e., the coating 12 located in the thinned area 4. However, the protruding direction of the tab is the same as the width direction Y of the pole piece body 1.

[0024] In the battery pole piece according to the present application, in the width direction Y of the pole piece body 1, the distance W between the edge of the slot area 3 and the edge of the pole piece body 1 is smaller than the width L of the thinning area 4, provided that 0 < W ≤ 8 mm. Specifically, the width L of the thinning area 4 can be understood as the thinned length of the end material of the slot in the direction in which the tab 2 protrudes. The distance W between the edge of the slot area 3 and the edge of the pole piece body 1 can be understood as the width of the end material facing the tab 2, and W ≤ L. After cutting the thinly shaved coating 12, it is not necessary to die-cut the paint remaining on the edge of the slot, and it is ensured that the thickness of the entire cell is not affected, thereby improving the efficiency, yield and quality of the battery manufacturing process.

[0025] In the battery pole piece according to the present application, the coating 12 located in the thinning area 4 has a thinning portion 5 formed therein. The tab 2 is close to the thinning portion 5, and the thickness h of the thinning portion 5 is 10 to 50 μm. Controlling the thickness h of the thinning portion 5 is to avoid affecting the thickness of the entire cell. It can be understood that the thickness of the end material of the slot in the direction in which the tab 2 protrudes, for example, the thickness after thinning can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc., so as to be suitable for the tab 2.

[0026] In the battery pole piece according to the present application, the thickness H of the coating 12 located in the thinning area 4 before thinning is 20 to 100 μm. The thickness of the end material of the slot in the direction in which the tab 2 protrudes before thinning is controlled. For example, it can be understood that the thickness before thinning is controlled to be 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc. The thickness may be the same as or different from the thickness of the coating 2 in other areas, and is not limited here.

[0027] In the battery pole piece of the present application, the thinned thickness h1 of the coating 12 located in the thinned area 4 is 10 to 80 um, which can be understood as controlling the thinned thickness of the end material of the slot in the direction in which the tab 2 protrudes, for example, to be controlled to be 10 um, 20 um, 30 um, 40 um, 50 um, 60 um, 70 um, 80 um, etc., and the thinned thickness can be adapted to the thickness of the tab 2 to avoid affecting the thickness of the entire cell.

[0028] The lithium ion battery includes a cell, and the cell may include at least two pole pieces stacked on top of each other and having opposite polarities, the pole pieces being a positive pole piece and a negative pole piece of the battery, respectively. To prevent short circuits between the positive pole piece and the negative pole piece, a diaphragm is installed between each two adjacent pole pieces, and the pole pieces having opposite polarities are electrically isolated by the diaphragm. At least one of the pole pieces may be the battery pole piece.

[0029] The at least two pole pieces may include a first pole piece and a second pole piece, the polarities of the first pole piece and the second pole piece being opposite, and the first pole piece and the second pole piece being arranged on top of each other.

[0030] Specifically, the first pole piece may be a positive pole piece and may adopt the positive pole piece structure according to Examples 1 to 8 above, and the second pole piece may be a negative pole piece, or the first pole piece may be a negative pole piece and the second pole piece may be a positive pole piece, and there are no limitations here.

[0031] In some examples, the cell may be a winding cell, in which the first pole piece and the second pole piece are one and the first pole piece, the diaphragm, and the second pole piece are sequentially stacked and wound around a winding center to form a winding structure.

[0032] In another example, the cell may be a stacked cell, in which there are a plurality of first pole pieces and a plurality of second pole pieces, the plurality of first pole pieces and the plurality of second pole pieces are stacked alternately in the same direction, and a diaphragm is provided between each adjacent first pole piece and each adjacent second pole piece to electrically insulate the first pole piece from the second pole piece.

[0033] The working principle of the present application is as follows. By thinning the coating 12 located in the thinned area 4 of the pole piece body 1, i.e., by thinning the coating 12 at the position facing the tab 2, it is no longer necessary to die-cut the slot or cut into the slot area after cutting, which not only simplifies the production process but also avoids battery safety issues that may occur in the above process, thereby improving the manufacturing efficiency and yield rate of the battery; furthermore, the slot area 3 is provided on the surface of the pole piece body 1, and the end of the tab 2 can be welded to the current collector 11 exposed on the surface of the slot area 3, and the tab 2 is close to the upper surface of the coating 12 in the thinned area 4, which avoids affecting the thickness of the entire cell.

[0034] Second embodiment The difference from the first embodiment is that the coating 12 according to this embodiment has a single-layer or multi-layer structure, and the coating 12 includes at least one of an active material layer, a security coating, a carbon coating, and an insulating coating in its thickness direction. Specifically, the thickness of the coating 12 may include the thickness of a single coating, or may be composed of two or more coatings. Among these, the single coating may be an active material coating; the two coatings may be a combination of an active material coating and a highly conductive carbon coating, or a combination of an active material coating and a thermally stable security coating, or a coating with stable chemical properties such as lithium iron phosphate, or an active material coating and a porous insulating coating such as a ceramic coating. The three or more coatings may be a combination of any of the above coatings.

[0035] The other structures are the same as those of the first embodiment, so detailed descriptions will not be repeated here.

[0036] Third embodiment The difference from the first embodiment is that the coating 12 located in the slot area 3 of this embodiment has a slot 6 formed therein, the slot 6 including a bottom and side walls, the side walls extending upward from the bottom, the bottom being a current collector 11 exposed on the surface of the pole piece body 1, and the coating 12 surrounding the slot 6 to form the side walls. Therein, the slot 6 has four side walls, the four side walls and the bottom surrounding the slot 6, the bottom being a current collector 11 exposed to the outside, and the tab 2 is welded to the current collector 11 therein.

[0037] The other structures are the same as those of the first embodiment, so detailed descriptions will not be repeated here.

[0038] Manufacturing method of battery pole pieces The manufacturing method of the battery pole piece is as follows: applying a slurry of coating 12 to a current collector 11; forming the slot 6 by scraping or laser cleaning the coating 12 in the slot area 3; forming a thinned portion 5 by thinning the coating 12 in the thinned area 4; The pole piece is washed, roll pressed and cut in order, and the wide pole piece is cut into a plurality of pole piece bodies 1; welding an end of the tab 2 to the slot 6 so that a portion of the tab 2 is adjacent to the thinned portion 5; Includes:

[0039] However, the active material slurry is applied to the current collector 11 by a coater, and is applied to both sides, and then the current collector 11 is dried by baking and wound up.

[0040] Referring to FIG. 5, the wide pole piece is cleaned by a laser to form a slot 6, scraped by a blade method to form a slot 6, or otherwise formed with a slot 6 for welding the tab 2.

[0041] In the process of creating the slots 6, the coating material on the current collector 11 can be cleaned by focusing the energy generated by the laser. After cleaning to form the slots 6, the coating 12 on the edge of the slots 6 can be cleaned again or the surface coating 12 can be thinned with a blade. In this process, a vacuum negative pressure dust removal device 103 is added at the same time as the laser cleaning or blade treatment to remove the pole powder generated on the pole pieces, and the laser power when cleaning the coating 12 on the edge of the slots 6 again is smaller than the laser power when cleaning the slots 6.

[0042] 7 and 8, the laser cleaning device includes, but is not limited to, a laser emitter 7, a galvanometer mirror 8, a field lens 9, and a platform 10, arranged in this order from top to bottom. A total reflection mirror and an output reflection mirror are arranged in parallel within the laser emitter 7, and the laser passes through the total reflection mirror and output reflection mirror in sequence, and then passes through an isolator before being emitted. The isolator serves a protective role, isolating the laser that is reflected back during operation and ensuring the safety of the optical path. The galvanometer mirror 8 can reflect the laser and refract it at different angles. The field lens 9 can control the focal length of the laser and the marking area. The platform 10 is located at the bottom and can transport the pole piece to a pre-installed position to perform laser cleaning.

[0043] 9, the blade treatment includes, but is not limited to, a blade 101, a fan 102, a vacuum negative pressure dust removal device 103, and a stage 104. The blade 101 and the stage 104 can be made of tungsten steel or other metals, the pole piece is fixed on the stage 104, the blade 101 is perpendicular to the pole piece and scrapes off the coating 12 by reciprocating motion, and the fan 102 and the vacuum negative pressure dust removal device 103 are located on both sides of the blade 101 and can remove the pole powder generated on the pole piece.

[0044] Referring to Figures 1 to 4, the thinned coating 12 may be the coating on the surface where the tab 2 is welded, or it may be a coating on both sides. Depending on the actual situation, the slot 6 and the thinned coating 12 obtained by laser cleaning or blade method can be physically cleaned again with a brush to clean loose floating dust on the surface again, and the workstation can be wiped with dust-free paper to wipe off the dust on the surface, so that the coating 12 in the thinned area will not shed powder in the subsequent processing process. In this, the thinned length L of the slot end material in the direction in which each tab 2 protrudes is W≦L, the thickness H of the slot end material in the direction in which each tab 2 protrudes before thinning is controlled to 20 to 100 um, the thinned thickness h1 of the slot end material in the direction in which each tab 2 protrudes is controlled to 10 to 80 um, and the thickness h of the slot end material in the direction in which each tab 2 protrudes after thinning is controlled to 10 to 50 um, and the coating 12 on the surface in contact with the tab 2 may be thinned, or the coating 12 on both surfaces may be thinned.

[0045] Referring to Figures 5 and 6, the pole pieces are subjected to a roll pressing and cutting process, in which the wide pole pieces are cut into small pole pieces.

[0046] According to the disclosure and teachings of the above specification, those skilled in the art of the present application may make changes and modifications to the above-described embodiments. Therefore, the present application is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present application fall within the scope of protection of the present application. In addition, although some specific terms are used in this specification, these terms are merely for the purpose of facilitating description and do not impose any limitations on the present application. [Explanation of symbols]

[0047] 1 Pole piece body 11 Current collector 12 Coating 2 Tabs 3 Slot Area 4 Thinning area 5 Thinned part 6 slots 7 Laser Emitter 8 Galvanometer Mirror 9 Field Lens 10 Platform 101 Blade 102 Fans 103 Vacuum negative pressure dust removal device 104 Stages Y width direction

Claims

1. It includes a pole piece body (1) and a tab (2), The pole piece body (1) includes a current collector (11) and a coating (12) applied to the surface of the current collector (11), and the surface of the pole piece body (1) has a slot area (3) and a thinned area (4), The current collector (11) is exposed on the surface of the slot area (3) of the pole piece body (1) and is welded to the end of the tab (2); The battery pole piece is characterized in that the coating (12) is exposed on the surface of the thinned area (4) of the pole piece body (1) and is adjacent to the tab (2).

2. 2. The battery pole piece according to claim 1, characterized in that the thinned area (4) of the pole piece body (1) is located between the edge of the slot area (3) and the edge of the pole piece body (1).

3. The battery pole piece according to claim 1, characterized in that the distance W between the edge of the slot area (3) and the edge of the pole piece body (1) in the width direction (Y) of the pole piece body (1) is smaller than the width L of the thinned area (4), provided that 0 < W ≦ 8 mm.

4. The battery pole piece according to claim 1, characterized in that the coating (12) located in the thinned area (4) has a thinned portion (5) formed therein, the tab (2) is adjacent to the thinned portion (5), and the thickness h of the thinned portion (5) is 10 to 50 μm.

5. The battery pole piece according to claim 4, characterized in that the thickness H of the coating (12) located in the thinned area (4) before thinning is 20 to 100 um.

6. The battery pole piece according to claim 4, characterized in that the thinned thickness h1 of the coating (12) located in the thinned area (4) is 10 to 80 um.

7. 2. The battery pole piece according to claim 1, wherein the coating (12) has a single layer structure or a multi-layer structure.

8. 8. The battery pole piece according to claim 7, wherein the coating (12) comprises, in its thickness direction, at least one of an active material layer, a security coating, a carbon coating, and an insulating coating.

9. 2. The battery pole piece according to claim 1, characterized in that the coating (12) located in the slot area (3) has a slot (6) formed therein, the slot (6) including a bottom and a side wall, the side wall extending upward from the bottom, the bottom being a current collector (11) exposed on the surface of the pole piece body (1), and the coating (12) surrounding it to form the side wall.

10. Applying a slurry of coating (12) to a current collector (11); forming a slot (6) by scraping or laser cleaning the coating (12) in the slot area (3); forming a thinned portion (5) by thinning the coating (12) in the thinned area (4); The pole pieces are washed, roll pressed, and cut into pieces in order. welding an end of the tab (2) to the slot (6) so that a portion of the tab (2) is adjacent to the thinned portion (5); A method for manufacturing a battery pole piece, comprising:

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