Battery pole piece coating roller and lithium battery pole piece preparation method

Abstract

The application provides a battery pole piece coating roller and a lithium battery pole piece preparation method, and belongs to the technical field of lithium ion battery preparation. The battery pole piece coating roller comprises a roller body and a connecting shaft. The roller body is provided with a first roller pressing end face and a second roller pressing end face at both ends in the length direction. The first roller pressing end face and the second roller pressing end face are perpendicular to the axis of the roller body, the edge of the first roller pressing end face is provided with a plurality of first strip-shaped recesses which are recessed along the axis direction of the roller body, and the plurality of first strip-shaped recesses are uniformly and spacedly arranged around the circumference of the roller body. The connecting shaft is used for driving the roller body to rotate around the axis, and the connecting shaft is perpendicularly connected to the first roller pressing end face and the second roller pressing end face and coaxial with the roller body. The battery pole piece coating roller can realize accurate coating of the battery pole piece, increase the area of the current collector pole piece coated with active material, ensure the number of blank areas of the lug welding position, reduce the processing procedure, and improve the yield of the battery pole piece.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion battery preparation, and in particular to a battery pole piece coating roller and a lithium battery pole piece preparation method. BACKGROUND

[0002] Nowadays, electric vehicles have entered a rapid development stage, but charging time and cruising range are still the pain points hindering the development of electric vehicles. Lithium ion power batteries have become the preferred power source for new energy vehicles due to their high energy density, long cycle life, environmental friendliness and other characteristics.

[0003] In related technologies, the winding type electrode structure is the main form of the current lithium ion battery assembly process. When preparing lithium ions, a position for welding the tab is left on the current collector, and the rest is coated with electrode paste. In order to ensure the blank area for welding the tab, a peelable adhesive sheet is usually pasted on the current collector. After the current collector is coated with active paste and dried by heating, the adhesive sheet falls off, and the original adhesive position exposes the current collector foil, which is used for welding the tab.

[0004] Using the coating method in related technologies, additional adhesive sheet pasting equipment needs to be added in the preparation process of the pole piece, the process is complex, and the production cost is high. At the same time, there is a probability that the coating layer near the adhesive sheet will be peeled off from the pole piece along with the adhesive sheet during the drying and falling off process, resulting in a low yield of the battery pole piece. SUMMARY

[0005] The present application provides a battery pole piece coating roller and a lithium battery pole piece preparation method, which can realize accurate coating of the battery pole piece, increase the area of the current collector pole piece coated with active material, and ensure the number of blank areas for tab welding position, reduce the processing procedure, and improve the yield of the battery pole piece. The technical solution is as follows:

[0006] In the first aspect, the present application provides a battery pole piece coating roller, comprising:

[0007] A roller body has a first roller pressing end face and a second roller pressing end face at both ends in the length direction, the first roller pressing end face and the second roller pressing end face are perpendicular to the axis of the roller body, the edge of the first roller pressing end face has a plurality of first strip-shaped grooves recessed along the axis direction of the roller body, and a plurality of the first strip-shaped grooves are uniformly and spacedly arranged around the circumference of the roller body.

[0008] A connecting shaft is used to drive the roller body to rotate around the axis, and the connecting shaft is connected perpendicularly to the first roller pressing end face and the second roller pressing end face and coaxially with the roller body.

[0009] Optionally, the edge of the second roll-pressing end surface has a plurality of second strip-shaped grooves recessed along the axial direction of the roller body, and the plurality of second strip-shaped grooves are uniformly and spacedly arranged around the circumferential direction of the roller body.

[0010] Optionally, the number of the plurality of second strip-shaped grooves is the same as that of the plurality of first strip-shaped grooves, the depth of the second strip-shaped grooves and the first strip-shaped grooves in the axial direction of the roller body is the same, and the width of the second strip-shaped grooves and the first strip-shaped grooves in the circumferential direction of the roller body is different.

[0011] Optionally, the number of the plurality of second strip-shaped grooves is the same as that of the plurality of first strip-shaped grooves, the depth of the second strip-shaped grooves and the first strip-shaped grooves in the axial direction of the roller body is the same, and the width of the second strip-shaped grooves and the first strip-shaped grooves in the circumferential direction of the roller body is different.

[0012] Optionally, the number of the plurality of second strip-shaped grooves is different from that of the plurality of first strip-shaped grooves, and the depth of the second strip-shaped grooves and the first strip-shaped grooves in the axial direction of the roller body and the width of the second strip-shaped grooves and the first strip-shaped grooves in the circumferential direction of the roller body are the same.

[0013] Optionally, the number of the plurality of second strip-shaped grooves is different from that of the plurality of first strip-shaped grooves, the depth of the second strip-shaped grooves and the first strip-shaped grooves in the axial direction of the roller body is the same, and the width of the second strip-shaped grooves and the first strip-shaped grooves in the circumferential direction of the roller body is different.

[0014] Optionally, the battery pole piece coating roller further comprises a first combined cover plate and a second combined cover plate, the first combined cover plate comprises a first disc cover body and a plurality of first filling blocks, the first disc cover body is slidably mounted on the connecting shaft connected with the first roll-pressing end surface, the first disc cover body is parallel to the first roll-pressing end surface and has the same diameter as the roller body, the plurality of first filling blocks are circumferentially and spacedly arranged on one side of the first disc cover body facing the first roll-pressing end surface, and the plurality of first filling blocks are matched with and correspond to the plurality of first strip-shaped grooves.

[0015] The second combined cover plate comprises a second disc cover body and a plurality of second filling blocks, the second disc cover body is slidably mounted on the connecting shaft connected with the second roll-pressing end surface, the second disc cover body is parallel to the second roll-pressing end surface and has the same diameter as the roller body, the plurality of second filling blocks are circumferentially and spacedly arranged on one side of the second disc cover body facing the second roll-pressing end surface, and the plurality of second filling blocks are matched with and correspond to the plurality of second strip-shaped grooves.

[0016] Optionally, the first strip-shaped groove has a depth of 20 mm in the axial direction of the roller body, and a width of 30 mm in the circumferential direction of the roller body.

[0017] In a second aspect, the embodiments of the present application further provide a lithium battery pole piece preparation method, which is realized based on the battery pole piece coating roller of the first aspect, and the method comprises the following steps of:

[0018] A current collector foil is provided, and a tab is welded on the side edge of the current collector foil at a predetermined interval in the coating direction;

[0019] An active slurry is coated on the current collector foil by using a coating machine provided with the battery pole piece coating roller to form a pole piece.

[0020] Optionally, the lithium battery pole piece preparation method further comprises the following steps of:

[0021] The pole piece coated with the active slurry is dried;

[0022] The pole piece is cold-pressed by using a cold-pressing roller, the cold-pressing roller has the same length and diameter as the roller body, the two ends of the cold-pressing roller in the length direction have third roller pressing end faces and fourth roller pressing end faces, the third roller pressing end faces and the fourth roller pressing end faces are perpendicular to the axis of the cold-pressing roller, the edge of the third roller pressing end face has a plurality of third strip-shaped grooves recessed in the axial direction of the cold-pressing roller, the plurality of third strip-shaped grooves are uniformly and spacedly arranged in the circumferential direction of the cold-pressing roller, the number of the plurality of third strip-shaped grooves is the same as and one-to-one corresponds to the number of the plurality of first strip-shaped grooves, the depth of the third strip-shaped groove in the axial direction of the cold-pressing roller is the same as the depth of the first strip-shaped groove in the axial direction of the roller body, and the width of the third strip-shaped groove in the circumferential direction of the cold-pressing roller is the same as the width of the first strip-shaped groove in the circumferential direction of the roller body.

[0023] A protective tape is double-sidedly attached to the tab welding position of the pole piece.

[0024] The technical scheme provided by the embodiments of the present application has at least the following beneficial effects:

[0025] The first plurality of strip-shaped grooves are evenly and circumferentially arranged on the first roller pressing end face, i.e., one end face of the roller body in the length direction. In the process of rotation of the roller body, the vacant positions of the first plurality of strip-shaped grooves will not be in contact with the current collector foil, i.e., the active slurry will not be coated on the current collector foil passing through the vacant positions, so as to form the blank area on the current collector foil for the welding of the tab. The tab can be welded on the specified position of the current collector foil before the coating process of the battery tab, and the opening position of the first plurality of strip-shaped grooves on the side surface of the roller body can accommodate the welded tab to pass through, without coating the active slurry on the tab. The battery tab is coated with the electrode slurry on the whole part except the tab position, and the battery tab prepared in this form can increase the coating area of the active material on the tab, and simultaneously improve the power performance and energy density without changing the material formula.

[0026] The battery tab coating roller provided by the embodiment of the present application can realize accurate coating of the battery tab by adjusting and optimizing the structure of the roller body, increase the area of the current collector tab coated with the active material, and ensure the number of blank areas of the tab welding position. The tab welding position on the current collector foil does not need to be shielded by the adhesive sheet, or the corresponding adhesive sheet is removed after the coating of the electrode slurry is completed, so that the processing procedure is reduced, and the yield of the battery tab is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 is a schematic diagram of the three-dimensional structure of the battery tab coating roller in operation provided by the embodiment of the present application;

[0029] Figure 2 is a schematic diagram of the front view structure of the battery tab coating roller provided by the embodiment of the present application;

[0030] Figure 3 is a schematic diagram of the structure of the first roller pressing end face and the second roller pressing end face in the first implementation manner of the embodiment of the present application;

[0031] Figure 4 is a schematic diagram of the structure of the first roller pressing end face and the second roller pressing end face in the second implementation manner of the embodiment of the present application;

[0032] Figure 5 is a schematic diagram of the structure of the first roller pressing end face and the second roller pressing end face in the third implementation manner of the embodiment of the present application;

[0033] Figure 6 Fig. 4 is a structural schematic diagram of the first and second roller pressing end faces in a fourth implementation manner of the embodiment of the present application;

[0034] Figure 7 Fig. 5 is a three-dimensional structural schematic diagram of another battery pole piece coating roller in work provided by the embodiment of the present application;

[0035] Figure 8 Fig. 6 is a front structural schematic diagram of another battery pole piece coating roller provided by the embodiment of the present application;

[0036] Figure 9 Fig. 7 is a three-dimensional structural schematic diagram of a cold pressing roller provided by the embodiment of the present application;

[0037] Figure 10 Fig. 8 is a flow chart of a lithium battery pole piece preparation method provided by the embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the object, technical scheme and advantages of the present application more clear, the embodiment of the present application will be further described in detail below with reference to the drawings.

[0039] In the related art, the winding type electrode structure is the main form of the current lithium ion battery assembly process. When the lithium ion is prepared, the position for welding the pole lug is left on the current collector, and the other parts are entirely coated with the electrode paste. In order to ensure the blank area for welding the pole lug, the peelable adhesive sheet is usually pasted on the current collector. After the current collector is coated with the active paste and is dried by heating, the adhesive sheet is peeled off, and the original pasted glue position exposes the current collector foil, which is used for welding the pole lug.

[0040] In the preparation process of the pole piece, the pasting equipment of the adhesive sheet needs to be additionally increased by using the coating method in the related art, and the process is complex and the production cost is high. Meanwhile, there is a probability that the coating layer coated near the adhesive sheet is peeled off from the pole piece along with the adhesive sheet in the process of drying and peeling off, which leads to the low yield of the battery pole piece.

[0041] Figure 1 Fig. 1 is a three-dimensional structural schematic diagram of a battery pole piece coating roller in work provided by the embodiment of the present application. Figure 2 Fig. 2 is a front structural schematic diagram of a battery pole piece coating roller provided by the embodiment of the present application. Figure 3 Fig. 3 is a structural schematic diagram of the first and second roller pressing end faces in a first implementation manner of the embodiment of the present application; Figure 4 Fig. 4 is a structural schematic diagram of the first and second roller pressing end faces in a fourth implementation manner of the embodiment of the present application; Figure 5 Fig. 5 is a structural schematic diagram of the first and second roller pressing end faces in a third implementation manner of the embodiment of the present application; Figure 6is a structural schematic diagram of a first roller pressing end face and a second roller pressing end face in a fourth implementation manner of the embodiment of the present application. Figure 7 is a three-dimensional structural schematic diagram of another battery pole piece coating roller in operation provided by the embodiment of the present application. Figure 8 is a front view structural schematic diagram of another battery pole piece coating roller provided by the embodiment of the present application. Figures 1 to 3 As shown, through practice, the applicant provides a battery pole piece coating roller, which comprises a roller body 1 and a connecting shaft 2.

[0042] The roller body 1 has a first roller pressing end face 11 and a second roller pressing end face 12 at two ends in the length direction. The first roller pressing end face 11 and the second roller pressing end face 12 are perpendicular to the axis of the roller body 1, and the edge of the first roller pressing end face 11 has a plurality of first strip-shaped grooves 111 recessed in the axis direction of the roller body 1. The plurality of first strip-shaped grooves 111 are uniformly and spacedly arranged around the circumference of the roller body 1.

[0043] The connecting shaft 2 is used to drive the roller body 1 to rotate around the axis, and the connecting shaft 2 is connected perpendicularly to the first roller pressing end face 11 and the second roller pressing end face 12 and coaxial with the roller body 1.

[0044] In the embodiment of the present application, the battery pole piece coating roller provided by the embodiment of the present application is used to coat the active slurry on the battery pole piece. The roller body 1 can be installed on a coating machine, the connecting shaft 2 is used to drive the roller body 1 to rotate around the axis, and the roller body 1 is used to transfer the active slurry to the current collector foil passing through. A plurality of first strip-shaped grooves 111 are uniformly and spacedly arranged around the circumference of the first roller pressing end face 11, that is, one end face of the roller body 1 in the length direction. In the process of rotating the roller body 1, the vacant position of the first strip-shaped groove 111 will not be in contact with the current collector foil, that is, the active slurry will not be coated on the current collector foil passing through this part of the vacant position, which is a blank area for welding the tab on the current collector foil. The tab can be welded on the specified position of the current collector foil before the coating process of the battery pole piece, and the opening position of the first strip-shaped groove 111 on the side surface of the roller body 1 can accommodate the welded tab to pass through when passing through the roller body 1, so that the active slurry will not be coated on the tab. The battery pole piece prepared in this form can increase the coating area of the active material on the pole piece, improve the power performance and energy density at the same time without changing the material formula. The battery pole piece coating roller provided by the embodiment of the present application can realize accurate coating of the battery pole piece by adjusting and optimizing the structure of the roller body 1, increase the area of the current collector pole piece coated with active material, and ensure the number of blank areas of the tab welding position. It is not necessary to stick a piece of adhesive film to shield the tab welding position on the current collector foil, or to scrape off the corresponding part after coating the electrode slurry, which reduces the processing procedure and effectively improves the yield of the battery pole piece.

[0045] Exemplarily, in the embodiment of the present application, according to different processes, the battery pole piece coating roller can also be used to weld the pole piece on the blank area left on the current collector foil after the active slurry coating is completed, and the embodiment of the present application does not limit this.

[0046] It should be noted that, in the embodiment of the present application, Figure 1 The processing shown is only one of the processing in actual production. In other possible implementations, the length of the roller body 1 can also be greater than the current collector foil to be coated, so that only the pole piece to be processed on one side is coated.

[0047] Optionally, the depth of the first strip-shaped groove 111 in the axial direction of the roller body 1 is 20 mm, and the width of the first strip-shaped groove 111 in the circumferential direction of the roller body 1 is 30 mm.

[0048] Optionally, the edge of the second roller pressing end face 12 has a plurality of second strip-shaped grooves 121 recessed in the axial direction of the roller body 1, and the plurality of second strip-shaped grooves 121 are uniformly and spaced apart in the circumferential direction of the roller body 1. Exemplarily, in the embodiment of the present application, a plurality of second strip-shaped grooves 121 are uniformly and spaced apart in the circumferential direction on the second roller pressing end face 12, that is, the other end face of the roller body 1 in the length direction. In the process of rotating the roller body 1, the hollow position of the second strip-shaped groove 121 will not be in contact with the current collector foil, that is, the active slurry will not be coated on the current collector foil passing through this part of the hollow position, leaving a blank area on the current collector foil for welding the tab. By using the roller body 1 provided with strip-shaped grooves on both ends, the blank area for welding the pole piece can be processed on both ends of the pole piece at the same time, or according to the interval between the adjacent two first strip-shaped grooves 111 and the adjacent two second strip-shaped grooves 121, the tab is welded on the specified position on both sides of the current collector foil before the coating process of the battery pole piece, and then the coating process is carried out, thereby improving the processing efficiency of the battery pole piece coating process.

[0049] Optionally, referring to Figure 3, the number of the plurality of second strip-shaped grooves 121 is the same as the number of the plurality of first strip-shaped grooves 111, the depth of the second strip-shaped groove 121 and the first strip-shaped groove 111 in the axial direction of the roller body 1 and the width in the circumferential direction of the roller body 1 are the same, and the second strip-shaped groove 121 and the corresponding first strip-shaped groove 111 are symmetrically arranged with respect to the roller body 1. For example, in one possible implementation, the plurality of first strip-shaped grooves 111 and the plurality of second strip-shaped grooves 121 at both ends of the roller body 1 are one-to-one corresponding, the corresponding first strip-shaped groove 111 and the second strip-shaped groove 121 are symmetrically arranged with respect to the roller body 1, and the opening width and the depth are the same. With such a roller body 1, the coating of the pole piece which requires the same size and spacing of the tabs on both sides can be realized.

[0050] Optionally, referring to Figure 4 , the number of the plurality of second strip-shaped grooves 121 is the same as the number of the plurality of first strip-shaped grooves 111, the depth of the second strip-shaped groove 121 and the first strip-shaped groove 111 in the axial direction of the roller body 1 is the same, and the width in the circumferential direction of the roller body 1 is different. For example, in another possible implementation, the corresponding width of the second strip-shaped groove 121 can be adaptively widened or reduced when forming, while the number or the corresponding relationship remains unchanged, with respect to the width of the first strip-shaped groove 111 in the circumferential direction of the roller body 1. When the number of tabs to be welded on both sides of the pole piece is the same, but the width size of the tabs in the coating direction is different, the roller body 1 provided in the embodiment can be used for coating processing.

[0051] Optionally, referring to Figure 5 , the number of the plurality of second strip-shaped grooves 121 is different from the number of the plurality of first strip-shaped grooves 111, the depth of the second strip-shaped groove 121 and the first strip-shaped groove 111 in the axial direction of the roller body 1 and the width in the circumferential direction of the roller body 1 are the same. For example, in another possible implementation, a plurality of second strip-shaped grooves 121 and first strip-shaped grooves 111 with the same opening width and depth can also be arranged at both ends of the roller body 1, but the number of the second strip-shaped grooves 121 is adjusted to be greater or less than the number of the first strip-shaped grooves 111. When the number of tabs to be welded on both sides of the pole piece is different, but the width size of the tabs in the coating direction is the same, the roller body 1 provided in the embodiment can be used for coating processing.

[0052] Exemplarily, in the embodiment of the present application, the internal shape of the first strip-shaped groove 111 or the second strip-shaped groove 121 can be rectangular or circular arc type, for example, the second strip-shaped groove 121 in the axial direction of the roller body 1 is circular arc type. The use of a circular arc type groove facilitates turning machining preparation and reduces machining procedures and difficulty. The embodiment of the present application does not limit the internal shape of the first strip-shaped groove 111 or the second strip-shaped groove 121, as long as it can ensure that the opening on the roller body 1 can avoid the lug welding position.

[0053] Optionally, referring to Figure 6 , the number of the plurality of second strip-shaped grooves 121 is different from the number of the plurality of first strip-shaped grooves 111, the depth of the second strip-shaped groove 121 and the first strip-shaped groove 111 in the axial direction of the roller body 1 is the same, and the width of the second strip-shaped groove 121 and the first strip-shaped groove 111 in the circumferential direction of the roller body 1 is different. Exemplarily, in another possible implementation manner of the embodiment of the present application, the number of the second strip-shaped groove 121 and the first strip-shaped groove 111 and the width in the circumferential direction of the roller body 1 can also be set to be different, so as to adapt to the case that the number of lugs required to be welded on both sides of the pole piece and the width of the lugs in the coating direction are different.

[0054] It should be noted that the above four types of roller body 1 can be adaptively switched according to different machining conditions, the roller body 1 and the connecting shaft 2 can be arranged in a detachable connection structure, and the above four types of roller body 1 can be simultaneously produced and arranged on the production line according to the actual working condition, so as to realize switching at any time and further improve the adaptability and practicality of the battery pole piece coating roller.

[0055] Optionally, referring to Figures 7 to 8 , the battery pole piece coating roller further comprises a first combined cover plate 21 and a second combined cover plate 22, the first combined cover plate 21 comprises a first disc cover body 211 and a plurality of first filling blocks 212, the first disc cover body 211 is slidably installed on the connecting shaft 2 connected with the first roller pressing end face 11, the first disc cover body 211 is parallel to the first roller pressing end face 11 and has the same diameter as the roller body 1, the plurality of first filling blocks 212 are circumferentially arranged on one side of the first disc cover body 211 facing the first roller pressing end face 11, the plurality of first filling blocks 212 are matched with and correspond to the plurality of first strip-shaped grooves 111;

[0056] The second combined cover plate 22 comprises a second disc cover body 221 and a plurality of second filling blocks 222. The second disc cover body 221 is slidably mounted on the connecting shaft 2 connected with the second roller pressing end face 12, and is parallel to the second roller pressing end face 12 and has the same diameter as the roller body 1. The plurality of second filling blocks 222 are circumferentially arranged on one side of the second disc cover body 221 facing the second roller pressing end face 12, and are matched with and correspond to the plurality of second strip-shaped grooves 121. For example, when the tabbed pole piece needs to be coated, the first combined cover plate 21 and the second combined cover plate 22 can be adjusted along the connecting shaft 2 to move away from the roller body 1, and the current collector foil is coated by using the roller body 1 with the first strip-shaped groove 111 and the second strip-shaped groove 121.

[0057] In another processing procedure, the first combined cover plate 21 and the second combined cover plate 22 can be adjusted in the opposite direction along the connecting shaft 2 to combine the first combined cover plate 21 and the second combined cover plate 22 with the roller body 1. The first disc cover body 211 is attached to the first roller pressing end face 11, and the plurality of first filling blocks 212 are correspondingly inserted into the plurality of first strip-shaped grooves 111. The second disc cover body 221 is attached to the second roller pressing end face 12, and the plurality of second filling blocks 222 are correspondingly inserted into the plurality of second strip-shaped grooves 121. The first combined cover plate 21, the roller body 1 and the second combined cover plate 22 are combined into a coating roller structure with a flat outer circular arc surface, and the tabbed pole piece which does not need to be left white for tab welding can be coated by using the combined coating roller structure. The two working conditions can be flexibly switched, further improving the practicality of the battery pole piece coating roller.

[0058] Figure 9 is a three-dimensional structure schematic diagram of a cold pressing roller provided by an embodiment of the present application. Figure 10 is a flowchart of a lithium battery pole piece preparation method provided by an embodiment of the present application. Figure 1 only Figure 10 As shown in the figure, the present application also provides a lithium battery pole piece preparation method based on the battery pole piece coating roller. Figures 1 to 8 The method comprises the following steps:

[0059] S1, providing a current collector foil, and welding tabs on the side edges of the current collector foil at a predetermined interval in the coating direction.

[0060] S2, using a coating machine provided with the battery pole piece coating roller to coat active paste on the current collector foil to make a pole piece.

[0061] Exemplarily, in this step, the coating machine provided with the aforementioned battery pole piece coating roller is used to coat and prepare the pole piece. Through the structural adjustment and optimization of the roller body, accurate coating of the battery pole piece can be realized, the area of the current collector pole piece coated with active material is increased, and the number of blank areas at the tab welding position is ensured. There is no need to stick a piece to shield the tab welding position on the current collector foil, or to scrape it after coating the electrode slurry, reducing the processing procedures and effectively improving the yield of the battery pole piece.

[0062] S3, drying the pole piece coated with the active slurry.

[0063] S4, cold pressing the pole piece by using a cold pressing roller 3, the length and diameter of the cold pressing roller 3 are the same as those of the roller body 1, the cold pressing roller 3 has a third roller pressing end face 31 and a fourth roller pressing end face 32 at both ends in the length direction, the third roller pressing end face 31 and the fourth roller pressing end face 32 are perpendicular to the axis of the cold pressing roller 3, the edge of the third roller pressing end face 31 has a plurality of third strip-shaped grooves 311 recessed in the axis direction of the cold pressing roller 3, the plurality of third strip-shaped grooves 311 are uniformly and spaced apart around the circumference of the cold pressing roller 3, the number of the plurality of third strip-shaped grooves 311 is the same as and one-to-one corresponds to the number of the plurality of first strip-shaped grooves 111, the depth of the third strip-shaped groove 311 in the axis direction of the cold pressing roller 3 is the same as the depth of the first strip-shaped groove 111 in the axis direction of the roller body 1, and the width of the third strip-shaped groove 311 in the circumferential direction of the cold pressing roller 3 is the same as the width of the first strip-shaped groove 111 in the circumferential direction of the roller body 1.

[0064] Exemplarily, in this step, after coating and drying, the pole piece enters the cold pressing stage. By using the cold pressing roller 3 with the same outer shape as the battery pole piece coating roller to cold press the coated pole piece, the hollow position of the third strip-shaped groove 311 will not contact the tab on the pole piece during the rotation of the cold pressing roller 3, avoiding extrusion and ensuring the yield of the battery pole piece.

[0065] S5, double-sidedly pasting a protective tape at the tab welding position of the pole piece.

[0066] Exemplarily, the battery pole group is formed by winding the positive and negative pole pieces and the separator. In this step, by double-sidedly pasting a protective tape at the tab welding position after the cold pressing process, it can prevent the welding spot at the tab welding position from piercing the separator during the subsequent winding process of the battery pole group and causing safety accidents.

[0067] Unless otherwise defined, technical terms or scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terms "first", "second", and similar terms do not denote any order, quantity, or importance, but are used to identify different components. Also, the terms "one", "another", and similar terms mean at least one. The terms "including", "containing", and similar terms are meant to be inclusive and are meant not to be limited to the components or objects listed after the terms. The terms "connected", "coupled", and similar terms are meant to be broad terms of functional adaption, and can include wired or wireless terms of connection or connection or connection that is direct or indirect, and can include active or passive connection or connection. The terms "upper", "lower", "left", "right", and similar terms are only used to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships may also be changed accordingly.

[0068] The above description is only optional embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing lithium battery electrodes, characterized in that, include: Provide current collector foil, and weld electrode tabs at predetermined intervals along the coating direction on the side of current collector foil; An active slurry is coated onto the current collector foil using a coating machine equipped with a battery electrode coating roller to form an electrode. The battery electrode coating roller includes: The roller body (1) has a first roller pressing end face (11) and a second roller pressing end face (12) at both ends in the length direction. The first roller pressing end face (11) and the second roller pressing end face (12) are perpendicular to the axis of the roller body (1). The edge of the first roller pressing end face (11) has a plurality of first strip grooves (111) recessed along the axis of the roller body (1). The plurality of first strip grooves (111) are evenly spaced around the circumference of the roller body (1). A connecting shaft (2) is used to drive the roller body (1) to rotate around the axis. The connecting shaft (2) is perpendicularly connected to the first roller pressing end face (11) and the second roller pressing end face (12) and is coaxial with the roller body (1). The edge of the second roller end face (12) has a plurality of second strip grooves (121) recessed along the axial direction of the roller body (1), and the plurality of second strip grooves (121) are evenly spaced around the circumference of the roller body (1); The battery electrode coating roller also includes a first combined cover plate (21) and a second combined cover plate (22). The first combined cover plate (21) includes a first disc cover body (211) and a plurality of first filler blocks (212). The first disc cover body (211) is slidably mounted on the connecting shaft (2) connected to the first roller pressing end face (11). The first disc cover body (211) is parallel to the first roller pressing end face (11) and has the same diameter as the roller body (1). The plurality of first filler blocks (212) are circumferentially spaced on the side of the first disc cover body (211) facing the first roller pressing end face (11). The plurality of first filler blocks (212) match and correspond one-to-one with the plurality of first strip grooves (111). The second combined cover plate (22) includes a second disc cover (221) and a plurality of second filler blocks (222). The second disc cover (221) is slidably mounted on the connecting shaft (2) connected to the second roller end face (12). The second disc cover (221) is parallel to the second roller end face (12) and has the same diameter as the roller body (1). The plurality of second filler blocks (222) are circumferentially spaced on one side of the second disc cover (221) facing the second roller end face (12). The plurality of second filler blocks (222) match and correspond one-to-one with the plurality of second strip grooves (121). The electrode sheet coated with the active slurry is dried; The electrode sheet is cold-pressed using a cold pressing roller (3). The cold pressing roller (3) has the same length and diameter as the roller body (1). The cold pressing roller (3) has a third pressing end face (31) and a fourth pressing end face (32) at both ends in the length direction. The third pressing end face (31) and the fourth pressing end face (32) are perpendicular to the axis of the cold pressing roller (3). The edge of the third pressing end face (31) has a plurality of third strip-shaped grooves (311) that are recessed along the axis of the cold pressing roller (3). The plurality of third strip-shaped grooves (311) are evenly spaced around the circumference of the cold pressing roller (3). The number of the plurality of third strip grooves (311) is the same as the number of the plurality of first strip grooves (111) and they correspond one-to-one. The depth of the third strip groove (311) in the axial direction of the cold pressing roller (3) is the same as the depth of the first strip groove (111) in the axial direction of the roller body (1). The width of the third strip groove (311) in the circumferential direction of the cold pressing roller (3) is the same as the width of the first strip groove (111) in the circumferential direction of the roller body (1). The empty position of the third strip groove (311) will not contact the tab on the electrode sheet. Protective tape is applied to both sides of the electrode tab welding position on the electrode sheet.

2. The method for preparing lithium battery electrodes according to claim 1, characterized in that, The number of the second strip grooves (121) is the same as the number of the first strip grooves (111) and they correspond one-to-one. The second strip grooves (121) and the first strip grooves (111) have the same depth in the axial direction of the roller body (1) and the same width in the circumferential direction of the roller body (1). The second strip grooves (121) and the corresponding first strip grooves (111) are arranged symmetrically with respect to the roller body (1).

3. The method for preparing lithium battery electrodes according to claim 1, characterized in that, The number of the second strip grooves (121) is the same as the number of the first strip grooves (111). The second strip grooves (121) and the first strip grooves (111) have the same depth in the axial direction of the roller body (1). The second strip grooves (121) and the first strip grooves (111) have different widths in the circumferential direction of the roller body (1).

4. The method for preparing lithium battery electrodes according to claim 1, characterized in that, The number of the second strip grooves (121) is different from the number of the first strip grooves (111). The second strip grooves (121) and the first strip grooves (111) have the same depth in the axial direction of the roller body (1) and the same width in the circumferential direction of the roller body (1).

5. The method for preparing lithium battery electrodes according to claim 1, characterized in that, The number of the second strip grooves (121) is different from the number of the first strip grooves (111). The second strip grooves (121) and the first strip grooves (111) have the same depth in the axial direction of the roller body (1). The second strip grooves (121) and the first strip grooves (111) have different widths in the circumferential direction of the roller body (1).

6. The method for preparing lithium battery electrode according to any one of claims 1 to 5, characterized in that, The first strip groove (111) has a depth of 20 mm in the axial direction of the roller body (1) and a width of 30 mm in the circumferential direction of the roller body (1).

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