Pole piece die cutting mechanism, die cutting machine and battery production line

Abstract

The utility model provides a pole piece die cutting mechanism, a die cutting machine and a battery production line, and belongs to the technical field of battery manufacturing. The pole piece die cutting mechanism comprises two passing rollers which are arranged in parallel and oppositely and a cutting structure, the cutting structure comprises an ultrasonic knife roller and an auxiliary roller which are arranged in parallel and oppositely, part of the pole piece passes through the space between the two passing rollers, and the side edge of the pole piece passes through the space between the ultrasonic knife roller and the auxiliary roller. A cutter is arranged on the outer circumferential face of the ultrasonic cutter roller in a protruding mode, and a cutter avoiding concave part is arranged on the outer circumferential face of the auxiliary roller. When the pole piece die cutting mechanism works, the ultrasonic knife roll and the auxiliary roll synchronously rotate in the opposite directions, and the cutter is in running fit with the cutter avoiding concave part, so that the side edge of a pole piece which moves in the conveying direction is cut to form a pole lug. Die cutting is achieved by means of the characteristic of ultrasonic vibration, the die cutting precision is improved, burrs generated on the edge of the formed pole piece are effectively reduced, and therefore the safety of the manufactured single battery is improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing, and in particular to a pole piece die-cutting mechanism, a die-cutting machine and a battery production line. Background Art

[0002] The pole piece of a battery cell includes a current collector and an active material layer coated on the surface of the current collector. During the pole piece forming stage, a die-cutting machine is usually required to cut the blank area on the pole piece that is not covered by the active material layer to form a pole ear. The current of the battery cell is conducted through the pole ear. However, a large number of burrs are generated on the edge of the pole piece after the pole ear is formed, which affects the safety of the battery cell. Utility Model Content

[0003] The present application aims to solve at least one of the technical problems in the background technology. To this end, one purpose of the present application is to provide a pole piece die-cutting mechanism, a die-cutting machine and a battery production line, which can effectively reduce the burrs generated on the edge of the pole piece after the pole ear is formed, thereby improving the safety of the manufactured battery cell.

[0004] The embodiment of the first aspect of the present application provides a pole piece die-cutting mechanism, including: a cutting structure and two rollers. The two rollers are arranged in parallel and opposite to each other, and the space between the two rollers is used for part of the pole piece to pass through. The cutting structure includes an ultrasonic knife roller and an auxiliary roller arranged in parallel and opposite to each other, and the space between the ultrasonic knife roller and the auxiliary roller is used for the side edge of the pole piece to pass through. The ultrasonic knife roller is coaxially arranged with one of the rollers and is sequentially distributed along the axis of one of the rollers. A cutter is protrudingly arranged on the outer circumferential surface of the ultrasonic knife roller, and the ultrasonic knife roller is configured to receive ultrasonic vibrations. The auxiliary roller is coaxially arranged with the other roller and is sequentially distributed along the axis of the other roller, and a knife-avoiding recess is provided on the outer circumferential surface of the auxiliary roller. Among them, the ultrasonic knife roller and the auxiliary roller are configured to be able to rotate synchronously in the opposite direction. When the ultrasonic knife roller and the auxiliary roller rotate, the cutter rotates and cooperates with the knife-avoiding recess, so that the side edge of the pole piece traveling along the transmission direction is cut to form a pole ear, and the cutter does not contact the auxiliary roller.

[0005] The pole piece die-cutting mechanism of the embodiment of the present application realizes die-cutting through the cooperation of the ultrasonic knife roller and the auxiliary roller. The ultrasonic knife roller can receive ultrasonic vibration. With the characteristics of ultrasonic vibration, the cutter of the ultrasonic knife roller can instantly and accurately transfer high-frequency vibration energy and heat to the surface of the side edge of the pole piece that contacts the cutter, so that the part is partially melted or softened and then cut. In this way, the die-cutting accuracy can be effectively improved, and the burrs generated on the edge of the pole piece after the pole ear is formed can be effectively reduced, thereby improving the safety of the manufactured battery cell.

[0006] In some embodiments, the auxiliary roller is constructed to include a first roller segment and a second roller segment arranged coaxially, the first roller segment is located on the side of the second roller segment that is opposite to the coaxial roller, the diameter of the second roller segment is smaller than the diameter of the first roller segment, the outer circumferential surface of the first roller segment and the outer circumferential surface of the second roller segment are connected by a connecting surface, the connecting surface and the outer circumferential surface of the second roller segment jointly define a knife-avoiding recess, and the connecting surface is at an angle to the axial direction of the auxiliary roller.

[0007] In this embodiment, the diameter of the portion of the auxiliary roller corresponding to the cutter is smaller than the diameter of the remaining portion, so as to form a cutter avoidance recess for avoiding the cutter. The design of the auxiliary roller in this example is simple, so as to simplify the manufacturing process of the auxiliary roller.

[0008] In some embodiments, the cutting knife includes a tab cutter and a straight-edge cutter. The straight-edge cutter is arranged along the circumference of the ultrasonic knife roller, and the two ends of the straight-edge cutter are respectively connected to the two ends of the tab cutter; the knife avoiding recessed portion is a knife avoiding groove structure formed by removing the portion of the outer circumferential surface of the auxiliary roller corresponding to the cutting knife, and the knife avoiding groove structure includes a curved groove and a tab-shaped groove. The curved groove is arranged along the circumference of the auxiliary roller, the curved groove cooperates with the straight-edge cutter, the tab-shaped groove cooperates with the tab cutter, and the two ends of the tab-shaped groove are connected to the curved groove.

[0009] In this embodiment, the knife-avoiding recessed portion is formed into a knife-avoiding groove structure, so that the knife-avoiding recessed portion and the cutter are more accurately matched. In this example, less material is removed from the outer circumferential surface of the auxiliary roller, which is conducive to making the auxiliary roller have a higher structural strength, and the auxiliary roller has a larger area for corresponding matching with the ultrasonic knife roller, which is conducive to improving the stability of the matching between the auxiliary roller and the ultrasonic knife roller.

[0010] In some embodiments, the connection between the straight-edge cutter and the tab cutter is smoothly transitioned, and the connection between the curved groove and the tab-shaped groove is smoothly transitioned. In this way, the connection between the tab of the pole piece obtained by die cutting and the side of the main body is also smoothly transitioned, which is conducive to reducing the stress concentration at the connection between the tab of the pole piece and the side of the main body, and helps to improve the quality of the pole piece.

[0011] In some embodiments, the first end of the ultrasonic knife roller is in contact with a coaxial roller, and the straight-edge cutter is arranged at the edge of the first end of the ultrasonic knife roller; the first end of the auxiliary roller is in contact with the axial end face of the coaxial roller, and the curved groove is arranged at the edge of the first end of the auxiliary roller.

[0012] In this embodiment, the curved groove is located at the edge of the first end of the auxiliary roller. When the curved groove is formed by machining such as turning and milling, chip removal is smoother during the machining process, which helps to reduce the machining difficulty.

[0013] In some embodiments, the knife avoidance groove structure has a first groove wall and a second groove wall, and the first groove wall and the second groove wall are arranged opposite to each other along the axial direction of the auxiliary roller. When the cutting knife and the knife avoidance groove structure rotate and cooperate, a gap is formed between the cutting knife and the first groove wall and between the cutting knife and the second groove wall, and the width of the gap is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0014] This embodiment achieves a good balance between the structural strength of the auxiliary roller and the tolerance of the pole piece die-cutting mechanism to errors, which can have a positive effect on improving the die-cutting quality.

[0015] In some embodiments, the height of the cutter is h, the depth of the cutter avoidance recess is H, and 0.5mm≤Hh≤2mm. This embodiment achieves a good balance between the structural strength of the auxiliary roller and the tolerance of the pole piece die-cutting mechanism to errors, which can have a positive effect on improving the die-cutting quality.

[0016] In some embodiments, the thickness of the cutter changes from being uniform everywhere to gradually decreasing from the root of the cutter to the tip of the cutter. This embodiment enables the cutter to withstand a larger cutting force, which can have a positive effect on the stability of the cutter in cutting the electrode sheet and is conducive to improving the cutting accuracy.

[0017] In some embodiments, a first negative pressure air duct is provided on the ultrasonic knife roller, and the air inlet end of the first negative pressure air duct passes through the outer circumference of the ultrasonic knife roller; the electrode die-cutting mechanism also includes an annular cover, and the number of annular covers is the same as the number of cutting structures; the annular cover is located on the side of the ultrasonic knife roller included in the corresponding cutting structure that is opposite to one of the rollers, and the annular cover is fixed by sliding cooperation with the rotating shaft connected to the corresponding ultrasonic knife roller through a first bearing, and the annular cover is provided with a second negative pressure air duct, and the air outlet end of the second negative pressure air duct passes through the outer circumference of the annular cover; during one rotation of the ultrasonic knife roller, the air inlet end of the first negative pressure air duct is connected to the air inlet end of the second negative pressure air duct when the ultrasonic knife roller is on the side opposite to the electrode material feeding direction, and the air outlet end of the first negative pressure air duct is cut off from the air inlet end of the second negative pressure air duct when the ultrasonic knife roller is on the side facing the electrode material feeding direction.

[0018] This embodiment utilizes the change in the connection relationship between the first negative pressure air channel and the second negative pressure air channel during one rotation of the ultrasonic knife roller, so that the waste formed by cutting is first adsorbed on the ultrasonic knife roller, so as to prevent the waste from continuing to be transported forward along the transmission direction with the electrode, and then the waste is allowed to fall naturally, so as to facilitate the subsequent cutting and collection of the waste.

[0019] In some embodiments, the first negative pressure air duct includes a negative pressure chamber and an exhaust hole, the negative pressure chamber penetrates the ultrasonic cutter roller along the axial direction of the ultrasonic cutter roller, the exhaust hole is arranged on the outer circumferential surface of the ultrasonic cutter roller and one end penetrates through the cavity wall of the negative pressure chamber; the second negative pressure air duct includes a connecting cavity and a negative pressure air port, one end of the connecting cavity penetrates through a side of the annular cover facing the ultrasonic cutter roller and is located on the side of the annular cover facing away from the direction of the electrode material, the negative pressure air port is arranged on the outer circumferential surface of the ultrasonic cutter roller and one end penetrates through the cavity wall of the connecting cavity.

[0020] In some embodiments, a plurality of rows of air extraction holes are arranged on the outer circumferential surface of the ultrasonic knife roller along its own axial direction, and each row of air extraction holes includes a plurality of air extraction holes arranged in sequence along the circumference of the ultrasonic knife roller.

[0021] In this embodiment, a plurality of air suction holes are provided and the plurality of air suction holes are arranged in multiple rows and columns, which not only provides a larger adsorption area, so that a larger area of ​​waste is adsorbed, but also helps to form a more uniform negative pressure distribution on the outer circumference of the ultrasonic knife roller.

[0022] In some embodiments, the pole piece die-cutting mechanism also includes two parallel and oppositely arranged rotating shafts, the two rotating shafts are configured to rotate synchronously in opposite directions and the speed is controllable, the two rotating shafts correspond one by one to the two rollers, the rollers are arranged on the corresponding rotating shafts through the second bearing, and the pole piece travels along the transmission direction, which can drive the rollers to rotate relative to the rotating shafts.

[0023] In this embodiment, the rotation speed of the ultrasonic knife roller and the auxiliary roller can be different from or the same as the rotation speed of the over roller, so that the rotation speed of the rotating shaft can be flexibly controlled, and the rotation speed of the ultrasonic knife roller and the auxiliary roller can be controlled, and then the width and spacing of the die-cut pole lugs can be controlled. Therefore, the pole lugs of the required width and the required size of the pole lug spacing can be processed according to the design requirements, and the pole piece die-cutting mechanism has good process compatibility and applicability.

[0024] An embodiment of the second aspect of the present application provides a die-cutting machine, which includes a conveying mechanism and a pole piece die-cutting mechanism of any one of the embodiments of the first aspect of the present application, the conveying mechanism is used to convey the pole piece, and the pole piece die-cutting mechanism is located downstream of the conveying mechanism.

[0025] An embodiment of the third aspect of the present application provides a battery production line, which includes a die-cutting machine according to any one of the embodiments of the second aspect of the present application.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0028] Figure 1 A schematic diagram of the three-dimensional structure of a pole piece die-cutting mechanism in some embodiments of the present application;

[0029] Figure 2 This is a schematic diagram of the structure of an ultrasonic knife roller according to some embodiments of the present application;

[0030] Figure 3 A partial schematic diagram of a pole piece die-cutting mechanism of some embodiments of the present application;

[0031] Figure 4 for Figure 3 A local enlarged schematic diagram of the middle A;

[0032] Figure 5 A partial schematic diagram of a molded pole piece produced by using a pole piece die-cutting mechanism according to some embodiments of the present application;

[0033] Figure 6 This is a schematic diagram of the structure of the auxiliary roller in some embodiments of the present application;

[0034] Figure 7 A cross-sectional schematic diagram of a partial structure of a pole piece die-cutting mechanism in some embodiments of the present application;

[0035] Figure 8 A three-dimensional schematic diagram of a partial mechanism of a pole piece die-cutting mechanism in some embodiments of the present application at a first viewing angle;

[0036] Fig. 9 This is a three-dimensional schematic diagram of a partial structure of a pole piece die-cutting mechanism in some embodiments of the present application at a second viewing angle.

[0037] Description of reference numerals:

[0038] Pole piece die cutting mechanism 100;

[0039] A roller 110, a first roller 110a, and a second roller 110b;

[0040] Cutting structure 120, ultrasonic knife roller 121, cutter 1211, tab cutter 1211a, straight edge cutter 1211b, air extraction hole 1212, negative pressure chamber 1213, second part 1214, auxiliary roller 122, knife avoidance recess 1221, tab-shaped groove 1221a, curved groove 1221b, first part 1222, first roller segment 1223, second roller segment 1224;

[0041] Rotating shaft 130, first rotating shaft 130a, second rotating shaft 130b;

[0042] An annular cover 140, a communicating cavity 141, a negative pressure air port 142, and a first bearing 143;

[0043] Driver 150;

[0044] Support plate 160;

[0045] Pole piece 200 , pole ear 210 , main body 220 , and waste material 230 . DETAILED DESCRIPTION

[0046] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0048] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0049] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0050] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0051] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0052] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0053] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements.

[0054] The term "parallel" in this application includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; at the same time, "vertical" also includes not only the absolutely vertical situation, but also the roughly vertical situation conventionally recognized in engineering. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0055] At present, some die-cutting machines of related technologies use laser cutting technology to realize the forming of the pole ear. The cutting principle is: the laser emits a high-energy laser beam, which irradiates the surface of the pole piece, causing the temperature of the local area of ​​the pole piece surface to rise sharply and then melt or vaporize, thereby realizing cutting. The die-cutting accuracy of the pole piece is not affected by a single factor, but is the comprehensive result of multiple factors. Among them, the factors affecting the die-cutting accuracy include the jitter of the incoming pole piece, the wrinkling of the pole piece, the fluctuation of the thickness of the active material layer, the die-cutting speed, etc. Based on this, when the laser uses the same process parameters to cut different batches of pole pieces, although the process parameters (such as laser power, speed, frequency, etc.) remain consistent, these factors will directly affect the die-cutting quality, resulting in the pole piece edge frying and a large number of burrs on the edge of the pole piece. For example, when the thickness of the active material layer of the electrode is uneven, the laser beam irradiates the thin part of the active material layer, and excessive heat is concentrated in this area, causing local overheating. The active material layer in this area will shrink, fall off, melt, etc. The melted active material layer will form molten beads in the cutting area, and excessive heat may also cause the current collector to melt and flow.

[0056] Some other related die-cutting machines are equipped with a cutter die mechanism, which includes a convex upper die and a concave lower die. The pole piece can be cut out of the pole ear through the cooperation of the convex upper die and the concave lower die. Although this can avoid the pole piece edge blasting due to laser overheating, the principle of this method of cutting is to squeeze and shear the pole piece through the convex upper die and the concave lower die. Since the edge of the pole piece is squeezed and deformed during the cutting process, a large number of burrs will be generated.

[0057] The presence of larger burrs may pierce the separator of the battery cell or overlap the positive / negative electrode of the battery cell, causing a short circuit inside the battery cell, resulting in severe current shock, which in turn causes ablation or even short circuit, affecting the safety of the battery. Although smaller burrs will not directly cause a short circuit, they may self-discharge, causing the battery cell to be over-discharged, thus causing safety problems inside the battery.

[0058] Based on the above considerations, in order to reduce the burrs generated on the edge of the pole piece after the pole ear is formed, a pole piece die-cutting mechanism, a die-cutting machine and a battery production line are designed. By setting a rotating auxiliary roller and an ultrasonic knife roller, the ultrasonic knife roller can receive ultrasonic vibrations, and a cutter is provided on the outer circumference of the ultrasonic knife roller, so that the cutter contacts the side edge of the pole piece at a high-frequency vibration frequency, and the high-frequency mechanical vibration energy can be accurately transmitted to the part where the side edge of the pole piece contacts the cutter. The high-frequency vibration of the ultrasonic knife roller will also generate heat in the contact area between the cutter and the side edge of the pole piece, so that the contact area is quickly heated. In this way, the contact area is cut by using high-frequency vibration and heat. In other words, the pole piece die-cutting mechanism uses ultrasonic cutting technology to achieve die-cutting.

[0059] The pole piece die-cutting mechanism provided in the embodiment of the present application is used to implement the die-cutting process so that the pole piece is formed into a pole ear. The pole piece die-cutting mechanism can be used to cut any one of the positive pole piece and the negative pole piece.

[0060] The positive electrode plate involved in the embodiment of the present application includes a positive current collector and a positive active material layer arranged on at least one surface of the positive current collector. As an example, the positive current collector has two surfaces opposite to each other in its own thickness direction, and the positive active material layer is arranged on any one or both of the two opposite surfaces of the positive current collector. As an example, the positive current collector may be a metal foil, a conductive polymer material, a carbon material or a composite current collector. For example, as a metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, nickel, titanium or silver, etc. may be used. As an example, the positive active material layer may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds.

[0061] The negative electrode plate involved in the embodiment of the present application includes a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector. As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material layer is arranged on any one or both of the two opposite surfaces of the negative electrode current collector. As an example, the negative electrode current collector may be a metal foil, a conductive polymer material, a carbon material or a composite current collector. For example, as a metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, nickel, titanium or silver, etc., may be used. As an example, the negative electrode active material layer may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc.

[0062] Figure 1 The three-dimensional structure diagram of the electrode die-cutting mechanism of some embodiments of the present application is schematically shown. The electrode die-cutting mechanism 100 provided in the embodiment of the present application is as follows: Figure 1 As shown, it includes: a cutting structure 120 and two rollers (110a, 110b, which can be individually or collectively referred to as "rollers 110"). The two rollers 110 are arranged in parallel and opposite to each other, and the space between the two rollers 110 is used for part of the pole piece 200 to pass. The cutting structure 120 includes an ultrasonic knife roller 121 and an auxiliary roller 122 arranged in parallel and opposite to each other, and the space between the ultrasonic knife roller 121 and the auxiliary roller 122 is used for the side edge of the pole piece 200 to pass. The ultrasonic knife roller 121 is configured as an ultrasonic transducer, and the ultrasonic knife roller 121 is coaxially arranged with one of the rollers 110 and distributed in sequence along the axis of one of the rollers 110, and the auxiliary roller 122 is coaxially arranged with the other roller 110 and distributed in sequence along the axis of the other roller 110.

[0063] Figure 2 The schematic diagram of the structure of the ultrasonic knife roller 121 in some embodiments of the present application is schematically shown. Figure 3 A partial schematic diagram of a pole piece die-cutting mechanism 100 of some embodiments of the present application is schematically shown. Figure 4 Schematically shows Figure 3 A local enlarged schematic diagram of the middle point. Figure 2 As shown, a cutter 1211 is protrudingly provided on the outer circumferential surface of the ultrasonic knife roller 121. Figure 3 and Figure 4 As shown, the outer circumferential surface of the auxiliary roller 122 is provided with a knife-avoiding recess 1221. The ultrasonic knife roller 121 and the auxiliary roller 122 are configured to be able to rotate synchronously in opposite directions. When the ultrasonic knife roller 121 and the auxiliary roller 122 rotate, the cutter 1211 and the knife-avoiding recess 1221 rotate in cooperation, so that the side edge of the pole piece 200 traveling along the transmission direction is cut to form the pole ear 210, and the cutter 1211 does not contact the auxiliary roller 122.

[0064] For the sake of clarity, the two rollers 110 are referred to as the first roller 110a and the second roller 110b. The axis of the roller 110 may be perpendicular to the horizontal plane or parallel to the horizontal plane. Figure 1 As shown, the axis of the roller 110 is parallel to the horizontal plane, and the two rollers 110 are arranged up and down, and the first roller 110a is located above the second roller 110b.

[0065] As an example, combine Figure 1 , Figure 3 and Figure 4 , the auxiliary roller 122 and the first roller 110a can be coaxial, and the ultrasonic knife roller 121 is coaxial with the second roller 110b. As an example, the auxiliary roller 122 and the second roller 110b can be coaxial, and the ultrasonic knife roller 121 is coaxial with the first roller 110a.

[0066] Among them, the outer circumferential surface of the ultrasonic knife roller 121 is coplanar with the outer circumferential surface of one of the rollers 110, and the outer circumferential surface of the auxiliary roller 122 is coplanar with the outer circumferential surface of the other roller 110, so that the two sides of the side edge of the pole piece 200 in the thickness direction are in stable contact with the ultrasonic knife roller 121 and the auxiliary roller 122. The ultrasonic knife roller 121 has the same rotation direction as one of the rollers 110, both of which are clockwise or counterclockwise. The auxiliary roller 122 has the same rotation direction as the other roller 110, both of which are counterclockwise or clockwise. The two rollers 110 have opposite rotation directions, and when the two rollers 110 rotate, the pole piece 200 has a tendency to be transported along the transmission direction.

[0067] by Figure 1The pole piece die-cutting mechanism 100 shown in the figure is used as a representative example to introduce the working process of the pole piece die-cutting mechanism 100. Figure 1 The first roller 110a and the auxiliary roller 122 rotate in the clockwise direction, and the second roller 110b and the ultrasonic knife roller 121 rotate in the counterclockwise direction. The ultrasonic knife roller 121 can receive ultrasonic vibrations and transmit the ultrasonic vibrations to the surface of the side edge of the pole piece 200 that contacts the cutter 1211 through the cutter 1211. Since the ultrasonic vibrations are high-frequency vibrations with high vibration frequency, the surface of the side edge of the pole piece 200 that contacts the cutter 1211 vibrates rapidly, and the high-frequency vibrations of the ultrasonic knife roller 121 will produce a local high-frequency thermal effect in the contact area between the blade and the side edge of the pole piece 200, so that the surface of the side edge of the pole piece 200 that contacts the cutter 1211 softens or melts, and then cooperates with the cutting force of the cutter 1211 to cut the side edge of the pole piece 200. The cutter 1211 reaches the side of the pole piece 200 facing away from the ultrasonic knife roller 121, and then rotates to cut into the knife avoidance recess 1221. The cutter 1211 does not contact the wall of the knife avoidance recess 1221, so the high-frequency vibration will not be transmitted to the auxiliary roller 122, so that the auxiliary roller 122 will not be cut. The two rollers 110, the auxiliary roller 122 and the ultrasonic knife roller 121 continue to rotate synchronously until one rotation, and the pole ear 210 is cut out of the side edge of the pole piece 200. After that, the pole piece 200 continues to move along the transmission direction, and the auxiliary roller 122 and the ultrasonic knife roller 121 continue to rotate to cut out the next pole ear 210. This reciprocating process eventually forms the pole piece 200, and the partial structure of the formed pole piece 200 is as shown. Figure 5 As shown. Among them, Figure 5 A partial schematic diagram of a molded pole piece 200 produced by using the pole piece die-cutting mechanism 100 of some embodiments of the present application is schematically shown.

[0068] The electrode die-cutting mechanism 100 of the embodiment of the present application realizes die-cutting through the cooperation of an ultrasonic knife roller 121 and an auxiliary roller 122. The ultrasonic knife roller 121 is designed to receive ultrasonic vibrations. By virtue of the characteristics of ultrasonic vibrations, the cutter 1211 of the ultrasonic knife roller 121 can instantly transmit high-frequency vibration energy and heat to the portion of the surface of the side edge of the electrode 200 that contacts the cutter 1211, so that the portion is locally melted or softened and then cut.

[0069] It can be understood that the pole piece die-cutting mechanism 100 achieves die-cutting of the pole piece 200 by means of the ultrasonic vibration of the ultrasonic knife roller 121 and the thermal effect generated in the contact area between the blade and the side edge of the pole piece 200, thereby eliminating burrs on the pole piece 200 caused by squeezing and shearing during the cutting process.

[0070] At the same time, compared with the laser cutting technology, although the pole piece die-cutting mechanism 100 of this embodiment also uses the heat generated by high-frequency vibration to achieve the cutting process, it can reduce the possibility of the pole piece 200 causing edge frying due to local overheating and generating a large number of burrs, and can effectively improve the die-cutting accuracy. This is because the heat is concentrated at the spot position during laser cutting, and the energy density of the laser is high, the heat will diffuse to a certain extent, and the heat-affected area is large. In this embodiment, the heat generated by high-frequency vibration comes from the local friction between the high-frequency vibrating cutter 1211 and the pole piece 200. This heat is much lower than the heat generated by the laser, and this heat is concentrated in the contact area between the cutter 1211 and the surface of the side edge of the pole piece 200, that is, the thermal effect is local, so the heat-affected area generated by these heat effects is small. In summary, using the pole piece die-cutting mechanism 100 to cut the pole piece 200 can effectively reduce burrs, thereby helping to improve the safety of the manufactured battery cell.

[0071] Since the pole piece die-cutting mechanism 100 of this embodiment has higher die-cutting accuracy, it can adapt to and compensate for the variation of the incoming pole piece 200. In other words, it can reduce the error caused by the parameter fluctuation of the incoming pole piece 200, thereby reducing the requirements for the incoming pole piece 200.

[0072] In some exemplary embodiments, please continue to refer to Figure 1 , Figure 3 and Figure 4 The pole piece die-cutting mechanism 100 may also include two parallel and oppositely arranged rotating shafts (130a, 130b, which may be individually or collectively referred to as "rotating shafts 130"). The two rotating shafts 130 are configured to rotate synchronously in opposite directions and the speed is controllable. The two rotating shafts 130 correspond one to one with the two rollers 110. The two rotating shafts 130 are respectively the first rotating shaft 130a and the second rotating shaft 130b. The first roller 110a and the auxiliary roller 122 are arranged on the first rotating shaft 130a, and the second roller 110b and the ultrasonic knife roller 121 are arranged on the second rotating shaft 130b. In this way, the first rotating shaft 130a rotates around its own axis, which can drive the first roller 110a and the auxiliary roller 122 to rotate, and the second rotating shaft 130b rotates around its own axis, which can drive the second roller 110b and the ultrasonic knife roller 121 to rotate.

[0073] In some exemplary embodiments, the pole piece die-cutting mechanism 100 may further include two support plates 160 that are parallel to each other and spaced apart along the axial direction of the roller 110, and both ends of the rotating shaft 130 are respectively connected to the two support plates 160, and the rotating shaft 130 can rotate relative to the support plates 160. In this example, the support plates 160 provide a mounting base for the rotating shaft 130.

[0074] In order to enable the rotating shaft 130 to rotate, the pole piece die-cutting mechanism 100 may also include two drivers 150, and the two drivers 150 correspond to the two rotating shafts 130 one by one, and each driver 150 is used to drive the corresponding rotating shaft 130 to rotate. Alternatively, in other embodiments of the present application, the pole piece die-cutting mechanism 100 may also be replaced by a driver 150 and a transmission mechanism, and the driver 150 is connected to the two rotating shafts 130 through the transmission mechanism to provide rotational power to the two rotating shafts 130 at the same time. In this example, the number of drivers 150 is reduced, which not only helps to lower the hardware cost of the pole piece die-cutting mechanism 100, but also helps to make the pole piece die-cutting mechanism 100 more compact. Among them, the transmission mechanism can adopt any one of a gear transmission mechanism, a chain transmission mechanism, a belt transmission mechanism, etc. The driver 150 can be, but is not limited to, a stepper motor, a servo motor, an AC motor, etc. In some embodiments of the present application, such as Figure 1 As shown, the driver 150 can be specifically arranged on the support plate 160 , that is, the support plate 160 is used to provide an installation and fixing basis for the driver 150 .

[0075] According to some embodiments of the present application, the pole piece die-cutting mechanism 100 may also include an ultrasonic generator and an ultrasonic transducer. The ultrasonic generator is connected to the ultrasonic transducer and provides a high-frequency electrical signal (higher than 20kHz) to the ultrasonic transducer. The ultrasonic transducer can convert the high-frequency electrical signal into mechanical vibration energy and transmit it to the ultrasonic knife roller 121. The ultrasonic generator can be specifically arranged on the support plate 160, that is, the support plate 160 is used to provide an installation and fixing foundation for the ultrasonic generator. In some exemplary embodiments, the ultrasonic transducer can be constructed as an annular member and arranged on the second rotating shaft 130b. The ultrasonic transducer is connected to the ultrasonic knife roller 121 and is located on the side of the ultrasonic knife roller 121 facing away from the second roller 110b. Alternatively, in other embodiments of the present application, the ultrasonic transducer constructed as an annular member can also be replaced by being sleeved between the second rotating shaft 130b and the ultrasonic knife roller 121. Alternatively, the ultrasonic transducer can also be replaced by being fixedly arranged on the axial end surface of the ultrasonic knife roller 121 facing away from the second roller 110b.

[0076] Please combine Figure 5The pole piece 200 includes a main body 220 and a plurality of pole tabs 210, wherein the pole tabs 210 extend from the side edge of the main body 220 along the width direction of the main body 220, and the plurality of pole tabs 210 are arranged in sequence along the length direction of the main body 220, and the side edge between two adjacent pole tabs 210 on the main body 220 is a straight edge. Among them, the distance between two adjacent pole tabs 210 in the length direction of the main body 220 is the pole tab spacing D. In order to cut out the pole tabs 210 and the straight edge side edges, the cutter 1211 can be specifically constructed to include a pole tab cutter 1211a and a straight edge cutter 1211b, wherein the straight edge cutter 1211b is arranged along the circumference of the ultrasonic knife roller 121, and the two ends of the straight edge cutter 1211b are respectively connected to the two ends of the pole tab cutter 1211a. It can be understood that the specific implementation methods of the knife avoidance recess 1221 are various.

[0077] Figure 6 The structure diagram of the auxiliary roller 122 of some embodiments of the present application is schematically shown. According to some embodiments of the present application, such as Figure 6 As shown, the auxiliary roller 122 can be specifically constructed to include a coaxially arranged first roller segment 1223 and a second roller segment 1224, the first roller segment 1223 is located on the side of the second roller segment 1224 that is opposite to the coaxial roller 110, the diameter of the second roller segment 1224 is smaller than the diameter of the first roller segment 1223, the outer circumferential surface of the first roller segment 1223 and the outer circumferential surface of the second roller segment 1224 are connected by a connecting surface, the connecting surface and the outer circumferential surface of the second roller segment 1224 jointly define a knife-avoiding recess 1221, and the connecting surface is at an angle to the axial direction of the auxiliary roller 122.

[0078] In this way, the outer circumference of the auxiliary roller 122 is stepped. The connecting surface may be perpendicular to the axial direction of the auxiliary roller 122, that is, the connecting surface is parallel to the radial direction of the auxiliary roller 122. Alternatively, the angle between the connecting surface and the axial direction of the auxiliary roller 122 is an acute angle, that is, the connecting surface is inclined to the axial direction of the auxiliary roller 122.

[0079] The height of the cutter 1211 protruding from the outer circumference of the ultrasonic cutter roller 121 is h, the diameter of the first roller segment 1223 is equal to the outer diameter of the ultrasonic cutter roller 121, and the difference between the diameter of the first roller segment 1223 and the diameter of the second roller segment 1224 is greater than 2h. In this example, when the pole piece die-cutting mechanism 100 is in operation, the cutter 1211 cooperates with the knife-avoiding recess 1221, and the cutter 1211 will not contact the outer circumference of the second roller segment 1224, so as to avoid transmitting ultrasonic vibration to the auxiliary roller 122 and causing the auxiliary roller 122 to be cut by mistake. Along the axial direction of the auxiliary roller 122, the normal distance between the straight-edge cutter 1211b and the end face of the first roller 110a close to the auxiliary roller 122 is the first distance. If the sum of the first distance and the maximum thickness of the cutter 1211 is less than the length of the second roller segment 1224, the cutter 1211 will not contact the connection surface.

[0080] In this embodiment, the diameter of the portion of the auxiliary roller 122 corresponding to the cutter 1211 (i.e., the second roller segment 1224) is smaller than the diameter of the remaining portion (i.e., the first roller segment 1223), and the outer circumferential surface of the second roller segment 1224 is farther away from the contact position between the auxiliary roller 122 and the ultrasonic knife roller 121 than the outer circumferential surface of the first roller segment 1223, so as to form a knife-avoiding recessed portion 1221 for avoiding the cutter 1211. In this example, the design of the auxiliary roller 122 is simple, which is conducive to simplifying the manufacturing process of the auxiliary roller 122. Moreover, in this method, the requirements for the precision of the rotational cooperation between the cutter 1211 and the knife-avoiding recessed portion 1221 are low, which is conducive to reducing the requirements for the manufacturing precision of the auxiliary roller 122.

[0081] According to some embodiments of the present application, the knife-avoiding recess 1221 may be a knife-avoiding groove structure formed by removing a portion of the outer circumferential surface of the auxiliary roller 122 corresponding to the cutting knife 1211. The knife-avoiding groove structure may specifically include a curved groove 1221b and an ear-shaped groove 1221a. The curved groove 1221b is arranged along the circumference of the auxiliary roller 122. The curved groove 1221b cooperates with the straight-edge cutter 1211b. The ear-shaped groove 1221a cooperates with the ear cutter 1211a. Both ends of the ear-shaped groove 1221a are connected to the curved groove 1221b.

[0082] The shape of the tab cutter 1211a and the tab-shaped groove 1221a are adapted to the shape of the tab 210, and this embodiment does not impose any specific restrictions on this. Figures 1 to 5 As shown, the tab 210 may be trapezoidal, and accordingly, the tab cutter 1211a and the tab groove 1221a are also trapezoidal in the unfolded state. Alternatively, the tab 210 may also be rectangular, and accordingly, the tab cutter 1211a is also rectangular in the unfolded state.

[0083] The curved groove 1221b may extend along the entire circumference of the auxiliary roller 122. In other words, the curved groove 1221b may be annular. Alternatively, the curved groove 1221b may also be arc-shaped. In this example, the two ends of the ear-shaped groove 1221a are respectively connected to the two ends of the curved groove 1221b.

[0084] When the pole piece die-cutting mechanism 100 of this embodiment is used to cut the pole piece 200, since the straight-edge cutter 1211b extends along the circumference of the ultrasonic knife roller 121, the ultrasonic knife roller 121 rotates a certain angle, and the straight-edge cutter 1211b continuously cuts the pole piece 200 to form a straight cutting track, thereby cutting a straight-edge side edge.

[0085] In this embodiment, the knife-avoiding recessed portion 1221 is formed into a knife-avoiding groove structure, so that the cooperation between the knife-avoiding recessed portion 1221 and the cutting knife 1211 is more precise. In this way, on the basis of being able to prevent the cutting knife 1211 from contacting the groove wall of the knife-avoiding groove structure and mistakenly cutting the auxiliary roller 122, compared with the embodiment in which the knife-avoiding recessed portion 1221 is formed by the connection surface and the outer circumferential surface of the second roller segment 1224, less material is removed from the outer circumferential surface of the auxiliary roller 122 in this example, which is conducive to making the auxiliary roller 122 have a higher structural strength, and the area of ​​the auxiliary roller 122 used for corresponding cooperation with the ultrasonic knife roller 121 is larger, which is conducive to improving the stability of the cooperation between the auxiliary roller 122 and the ultrasonic knife roller 121, so as to enable the pole piece die-cutting mechanism 100 to withstand a larger mechanical load.

[0086] In addition, due to the larger area of ​​the auxiliary roller 122 for matching with the ultrasonic knife roller 121, during the die-cutting process using the pole piece die-cutting mechanism 100, the auxiliary roller 122 and the ultrasonic knife roller 121 have a better clamping effect on the side edge of the pole piece 200, and the pressure applied by the auxiliary roller 122 to the side edge of the pole piece 200 is more uniform, which can reduce the possibility of the pole piece 200 moving during the die-cutting process, which is beneficial to improving the stability of the die-cutting process and helping to improve the die-cutting accuracy. Figures 1 to 4 As shown, during the operation of the pole piece die-cutting mechanism 100, when the curved groove 1221b and the straight-edge cutter 1211b rotate and cooperate, the ultrasonic knife roller 121 and the auxiliary roller 122 rotate synchronously in opposite directions for a certain angle, and the side edge of the pole piece 200 is cut to form a pole ear 210, and the formed pole ear 210 is clamped between the first part 1222 on the auxiliary roller 122 and the second part 1214 on the ultrasonic knife roller 121. Among them, the first part 1222 is located on the side of the pole ear-shaped groove 1221a facing the first roller 110a, that is, the pole ear-shaped groove 1221a is arranged along the pole ear-shaped edge of the first part 1222; the second part 1214 is located on the side of the pole ear cutter 1211a facing the second roller 110b, that is, the pole ear cutter 1211a is arranged along the pole ear-shaped edge of the second part 1214.

[0087] According to some embodiments of the present application, Figures 2 to 4 As shown, the connection between the straight-edge cutter 1211b and the tab cutter 1211a can be configured to have a smooth transition, and correspondingly, the connection between the curved groove 1221b and the tab-shaped groove 1221a also has a smooth transition.

[0088] The connection between the pole ear 210 of the pole piece 200 and the side edge of the main body 220 obtained by die cutting is also smooth. Figure 5 As shown, this helps to reduce the stress concentration at the connection between the pole ear 210 of the pole piece 200 and the side of the main body 220, which helps to improve the quality of the pole piece 200.

[0089] For similar reasons, this helps to reduce stress concentration at the connection between the straight-edge cutter 1211b and the pole ear cutter 1211a, and helps to reduce stress concentration at the connection between the curved groove 1221b and the pole ear groove 1221a, thereby helping to improve the durability of the cutter 1211 and extend the service life of the ultrasonic knife roller 121 and the auxiliary roller 122.

[0090] According to some embodiments of the present application, please refer to Figures 1 to 4 The first end of the ultrasonic knife roller 121 is in contact with the axial end face of the coaxial roller 110, and the straight-edge cutter 1211b can be specifically arranged at the first end edge of the ultrasonic knife roller 121. Correspondingly, the first end of the auxiliary roller 122 is in contact with the axial end face of the coaxial roller 110, and the curved groove 1221b is arranged at the first end edge of the auxiliary roller 122.

[0091] In this embodiment, the axial end surface of the first roller 110a and the auxiliary roller 122 define a curved groove 1221b together. When the pole piece die-cutting mechanism 100 of this embodiment is used to implement die-cutting, the portion of the pole piece 200 sandwiched between the two rollers 110 is formed as the main body 220, and the portion of the side edge of the pole piece 200 except the pole ear 210 becomes the waste material 230 and is separated from the main body 220.

[0092] In this embodiment, there is no gap between the first end face of the ultrasonic knife roller 121 and the axial end face of the coaxial roller 110, and there is no gap between the first end face of the auxiliary roller 122 and the axial end face of the coaxial roller 110, so that the pole piece 200 is clamped at all places along its own width direction, so as to improve the stability of the transmission of the pole piece 200.

[0093] Compared with the design in which the curved groove 1221b is located between the two end faces of the auxiliary roller 122, this embodiment benefits from the fact that the curved groove 1221b is located at the first end edge of the auxiliary roller 122. When the curved groove 1221b is formed by machining methods such as turning and milling, cutting can be performed along the axial or radial direction of the auxiliary roller 122, which is convenient for machining. Moreover, since the curved groove 1221b is open on both the side facing the first passing roller 110a and the side facing away from the bottom of the curved groove 1221b, chip removal is smoother during machining, which helps to reduce the difficulty of machining.

[0094] Figure 7 The cross-sectional view schematically shows the partial structure of the pole piece die-cutting mechanism 100 of some embodiments of the present application. According to some embodiments of the present application, such as Figure 7As shown, the knife-avoiding groove structure has a first groove wall and a second groove wall, and the first groove wall and the second groove wall are arranged opposite to each other along the axial direction of the auxiliary roller 122. When the cutter 1211 rotates with the knife-avoiding groove structure, a gap is formed between the cutter 1211 and the first groove wall and between the cutter 1211 and the second groove wall, and the width w of the gap can be specifically designed to be greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0095] The first groove wall is farther from the first roller 110a than the second groove wall. The cutter 1211 has two opposite sides along its thickness direction. The width of the gap between the one side facing the first groove wall and the first groove wall is in the range of [0.5mm, 2mm], and can be any value among 0.5mm, 1mm, 1.2mm, 1.5mm, and 2mm. The width of the gap between the other side facing the second groove wall and the second groove wall is also in the range of [0.5mm, 2mm], and can be any value among 0.5mm, 1mm, 1.2mm, 1.5mm, and 2mm.

[0096] On the one hand, by making the gap width w between the cutter 1211 and the first groove wall and the second groove wall not less than 0.5 mm, the gap width w will not be too small, so that the equipment error (such as manufacturing error, assembly error) of the electrode die-cutting mechanism 100 and the incoming material variation of the electrode 200 (such as wrinkling of the electrode 200, fluctuation of the thickness of the active material layer) can be provided with a tolerance space, so as to facilitate the normal rotation of the cutter 1211 and the knife-avoiding groove structure during the die-cutting process, so as to effectively prevent the cutter 1211 from touching the first groove wall and / or the second groove wall due to the above-mentioned equipment error and the incoming material variation of the electrode 200, so as to avoid miscutting. On the other hand, by making the gap between the cutter 1211 and the first groove wall and the second groove wall not more than 2 mm, the outer circumferential surface of the auxiliary roller 122 is less material removed, which is conducive to making the auxiliary roller 122 have a higher structural strength, so that the gap width w will not be too large, and it is conducive to making the matching accuracy between the cutter 1211 and the knife-avoiding groove structure higher. In general, this embodiment achieves a good balance between the structural strength of the auxiliary roller 122 and the tolerance of the pole piece die-cutting mechanism 100 to errors, which can have a positive effect on improving the die-cutting quality.

[0097] According to some embodiments of the present application, the height of the cutting knife 1211 is h, the depth of the cutting knife avoiding recess 1221 is H, and h and H can be designed to satisfy: 0.5 mm ≤ Hh ≤ 2 mm.

[0098] In combination with the above description, it can be known that in the embodiment where the connecting surface and the outer circumferential surface of the second roller segment 1224 jointly define the knife-avoiding recessed portion 1221, the difference between the diameter of the first roller segment 1223 and the diameter of the second roller segment 1224 is 2H. In the embodiment where the knife-avoiding recessed portion 1221 is a knife-avoiding groove structure, when the cutting knife 1211 rotates with the knife-avoiding groove structure, the distance between the tip of the cutting knife 1211 and the groove bottom of the knife-avoiding groove structure facing the tip is Hh.

[0099] Among them, Hh can specifically be any value among 0.5mm, 1mm, 1.2mm, 1.5mm, and 2mm.

[0100] On the one hand, by making Hh not less than 0.5mm, the distance between the tip of the cutter 1211 and the auxiliary roller 122 will not be too small, so that the equipment error (such as manufacturing error, assembly error) of the electrode die-cutting mechanism 100 and the incoming material variation of the electrode 200 (such as wrinkling of the electrode 200, fluctuation of the thickness of the active material layer) can be provided with tolerance space, so as to facilitate the normal rotation of the cutter 1211 and the knife avoidance groove structure during the die-cutting process, so as to effectively prevent the tip of the cutter 1211 from touching the auxiliary roller 122 due to the above-mentioned equipment error and the incoming material variation of the electrode 200, so as to avoid miscutting. On the other hand, by making Hh not greater than 2mm, less material is removed from the outer circumferential surface of the auxiliary roller 122, which is conducive to making the auxiliary roller 122 have a higher structural strength, so that the distance between the tip of the cutter 1211 and the auxiliary roller 122 will not be too large. In general, this embodiment achieves a good balance between the structural strength of the auxiliary roller 122 and the tolerance of the pole piece die-cutting mechanism 100 to errors, which can have a positive effect on improving the die-cutting quality.

[0101] It is understandable that the specific structure of the aforementioned cutter 1211 is also diverse. As some embodiments of the present application, the cutter 1211 can be designed such that the thickness of the cutter 1211 gradually decreases from the root of the cutter 1211 to the tip of the cutter 1211 .

[0102] According to some embodiments of the present application, Figure 3 and Figure 4 As shown, the cutter 1211 can also be designed so that the thickness of the cutter 1211 changes from being equal everywhere to gradually decreasing from the root of the cutter 1211 to the tip of the cutter 1211.

[0103] In this example, the cutter 1211 includes a connecting section and a blade section. One end of the connecting section is connected to the outer circumference of the ultrasonic knife roller 121, and the other end is connected to one end of the blade section. The thickness of the connecting section is equal everywhere, and the blade section gradually becomes thinner from one end connected to the connecting section to the other end. The specific implementation of the gradually thinning blade section includes but is not limited to the following possible situations. For example, Figure 3and Figure 4 As shown, one side of the blade head section along its thickness direction is perpendicular to the axial direction of the ultrasonic blade roller 121, and the other side extends obliquely from the connecting section to a side perpendicular to the axial direction of the ultrasonic blade roller 121. Alternatively, as Figure 7 As shown, both side surfaces of the cutter head section along its thickness direction extend obliquely from the connecting section and gradually approach each other.

[0104] Compared with the embodiment in which the cutter 1211 gradually becomes thinner from the root to the tip, without changing the parameters such as the height and maximum thickness of the cutter 1211, the cutter 1211 of this embodiment has a higher strength and can therefore withstand a greater cutting force. This can have a positive effect on the stability of the cutter 1211 in cutting the pole piece 200, thereby helping to improve the cutting accuracy.

[0105] Figure 8 The schematic diagram shows a partial structure of the pole piece die-cutting mechanism 100 in some embodiments of the present application in a three-dimensional view from a first viewing angle. Fig. 9 The schematic diagram of the partial mechanism of the pole piece die cutting mechanism 100 in some embodiments of the present application is shown in a three-dimensional diagram at a second viewing angle. It should be noted that: Figure 8 and Fig. 9 The annular cover 140 and the ultrasonic knife roller 121 shown in the figure are spaced apart from each other only for clearly illustrating the structures of the annular cover 140 and the ultrasonic knife roller 121 , and should not be regarded as limiting the present application.

[0106] According to some embodiments of the present application, Figure 8 and Fig. 9 As shown, the ultrasonic cutter roller 121 may be further provided with a first negative pressure airway, and the air inlet end of the first negative pressure airway passes through the outer circumference of the ultrasonic cutter roller 121. At the same time, the pole piece die-cutting mechanism 100 may also include an annular cover 140, and the number of the annular covers 140 is the same as the number of the cutting structures 120. The annular cover 140 is located on the side of the ultrasonic cutter roller 121 included in the corresponding cutting structure 120 that faces away from one of the rollers 110. The annular cover 140 is slidably matched with the rotating shaft 130 connected to the corresponding ultrasonic cutter roller 121 through the first bearing 143 to be fixed. The annular cover 140 is provided with a second negative pressure airway, and the air outlet end of the second negative pressure airway passes through the outer circumference of the annular cover 140. Moreover, during one rotation of the ultrasonic knife roller 121, when the air inlet end of the first negative pressure air duct is on the side of the ultrasonic knife roller 121 facing away from the material feeding direction of the electrode piece 200, the air outlet end of the first negative pressure air duct is connected with the air inlet end of the second negative pressure air duct, and when the ultrasonic knife roller 121 is on the side facing the material feeding direction of the electrode piece 200, the connection between the air outlet end of the first negative pressure air duct and the air inlet end of the second negative pressure air duct is cut off.

[0107] The outlet end of the second negative pressure airway can be connected to the negative pressure equipment through the exhaust pipe or can be connected to the factory exhaust pipe where the pole piece die cutting mechanism 100 is located through the exhaust pipe. The first bearing 143 can be implemented by a sliding bearing, a rolling bearing, etc., so that when the second rotating shaft 130b rotates, the annular cover 140 does not rotate therewith, and the position of the outlet end of the second negative pressure airway does not change, so that it can be stably connected to the negative pressure equipment or the factory exhaust pipe to achieve exhaust.

[0108] During the operation of the electrode die-cutting mechanism 100, the electrode 200 is carried along the transmission direction, and during the process of the first rotating shaft 130a and the second rotating shaft 130b rotating synchronously in the opposite direction for one circle (i.e., during the process of cutting out a pole ear 210 and the side between two adjacent pole ears 210), the air inlet end of the second negative pressure airway is kept in communication with the air outlet end of the first negative pressure airway to maintain air extraction. In addition, when the air inlet end of the first negative pressure airway rotates to the side facing away from the feeding direction of the electrode 200, the waste 230 formed by cutting is adsorbed on the surface of the ultrasonic knife roller 121 facing away from the feeding direction of the electrode 200 under the action of negative pressure. The air inlet end of the first negative pressure air duct continues to rotate with the second rotating shaft 130b, driving the waste material 230 to continue to be wound onto the ultrasonic knife roller 121, until the air inlet end of the first negative pressure air duct rotates to the side facing the incoming direction of the electrode 200, the air outlet end of the first negative pressure air duct is disconnected from the air inlet end of the second negative pressure air duct, and the waste material 230 formed by cutting is no longer affected by adsorption and falls naturally.

[0109] This embodiment utilizes the change in the connection relationship between the first negative pressure air channel and the second negative pressure air channel during one rotation of the ultrasonic knife roller 121, so that the waste 230 formed by cutting is first adsorbed on the ultrasonic knife roller 121, so as to prevent the waste 230 from continuing to be transported forward along the transmission direction with the electrode 200, and then the waste 230 falls naturally, so as to facilitate the subsequent cutting off and collection of the waste 230.

[0110] According to some embodiments of the present application, the first negative pressure airway may specifically include a negative pressure chamber 1213 and an air extraction hole 1212, wherein the negative pressure chamber 1213 penetrates the ultrasonic cutter roller 121 along the axial direction of the ultrasonic cutter roller 121, and the air extraction hole 1212 is arranged on the outer circumferential surface of the ultrasonic cutter roller 121 and one end thereof penetrates through the cavity wall of the negative pressure chamber 1213. The second negative pressure airway may specifically include a connecting chamber 141 and a negative pressure air port 142, wherein one end of the connecting chamber 141 penetrates through a side of the annular cover 140 facing the ultrasonic cutter roller 121 and is located on the side of the annular cover 140 facing away from the material feeding direction of the pole piece 200, and the negative pressure air port 142 is arranged on the outer circumferential surface of the ultrasonic cutter roller 121 and one end thereof penetrates through the cavity wall of the connecting chamber 141.

[0111] The suction hole 1212 is the air inlet of the first negative pressure airway, and the negative pressure air port 142 is the air outlet of the second negative pressure airway. The negative pressure chamber 1213 is located between the outer circumference and the inner circumference of the ultrasonic knife roller 121, and the connecting chamber 141 is located between the outer circumference and the inner circumference of the annular cover 140.

[0112] During the operation of the electrode die-cutting mechanism 100 of this embodiment, when the ultrasonic knife roller 121 rotates with the second rotating shaft 130b to the side of the air extraction hole 1212 facing away from the electrode 200 material feeding direction, the negative pressure chamber 1213 is opposite to the connecting chamber 141, the first negative pressure airway and the second negative pressure airway are connected, and the waste material 230 formed by cutting is adsorbed on the surface of the ultrasonic knife roller 121 facing away from the electrode 200 material feeding direction under the action of negative pressure. When the ultrasonic knife roller 121 rotates with the second rotating shaft 130b to the side of the air extraction hole 1212 facing the electrode 200 material feeding direction, the negative pressure chamber 1213 is not opposite to the connecting chamber 141, the first negative pressure airway and the second negative pressure airway are not connected, and the waste material 230 formed by cutting falls naturally.

[0113] The cross-sectional shape and size of the negative pressure chamber 1213 and the connecting chamber 141 in the direction perpendicular to the axial direction of the ultrasonic blade roller 121 may be consistent. Figure 2 and Figure 8 The cross-sectional shape of the negative pressure chamber 1213 in the axial direction perpendicular to the ultrasonic knife roller 121 can be an arc that is not closed in the circumferential direction, and the center of the arc is concentrically arranged with the center of the ultrasonic knife roller 121. The central angle corresponding to the arc can be any value of 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, 175°, and 180°.

[0114] The shape of the air extraction hole 1212 is not limited, and can be, but not limited to, circular, waist-shaped, rectangular, elliptical, etc. The number of the air extraction holes 1212 is also not limited, and can be, for example, one or more.

[0115] According to some embodiments of the present application, a plurality of rows of exhaust holes 1212 may be arranged at intervals on the outer circumferential surface of the ultrasonic knife roller 121 along its own axial direction, and each row of exhaust holes 1212 may include a plurality of exhaust holes 1212 arranged in sequence along the circumference of the ultrasonic knife roller 121 .

[0116] That is to say, there are multiple air extraction holes 1212, and the multiple air extraction holes 1212 are distributed in an array. Figure 2 As shown, the outer circumferential surface of the ultrasonic knife roller 121 is provided with 6 rows of air extraction holes 1212, and each row of air extraction holes 1212 has 16 air extraction holes 1212. Of course, the number of rows of air extraction holes 1212 and the number of air extraction holes 1212 in each row are not limited thereto.

[0117] In this embodiment, a plurality of exhaust holes 1212 are provided and the plurality of exhaust holes 1212 are arranged into multiple rows and columns. This not only provides a larger adsorption area, so that the adsorbed area on the waste 230 is larger, but also helps to form a more uniform negative pressure distribution on the outer circumference of the ultrasonic knife roller 121, thereby reducing the possibility of local adsorption being too strong or too weak, so that the waste 230 is evenly adhered to the outer circumference of the ultrasonic knife roller 121.

[0118] According to some embodiments of the present application, on the basis that the pole piece die-cutting mechanism 100 also includes two parallel and oppositely arranged rotating shafts 130, each roller 110 can be specifically set on the corresponding rotating shaft 130 through a second bearing, and the pole piece 200 is carried along the transmission direction, which can drive the roller 110 to rotate relative to the rotating shaft 130.

[0119] The second bearing can be realized by any one of sliding bearings, friction clutches, electromagnetic clutches, etc., so that the roller 110 can rotate along with the corresponding rotating shaft 130 and can rotate relative to the ultrasonic knife roller 121 and the auxiliary roller 122. The rotation speed of the roller 110 can be the same as or different from the rotation speed of the ultrasonic knife roller 121 and the auxiliary roller 122.

[0120] When the electrode die-cutting mechanism 100 of the present embodiment is applied to a die-cutting machine, according to the relationship formula between the angular velocity and the rotation angle, the rotation angle of the ultrasonic knife roller 121 and the auxiliary roller 122 can be controlled by controlling the rotation speed of the rotating shaft 130, and then according to the arc length formula, the length of the cutting track of the straight-edge cutter 1211b (i.e., the cutting length of the electrode 200 by the straight-edge cutter 1211b) can be controlled, thereby controlling the length of the side between two adjacent electrode tabs 210 formed by cutting, i.e., the electrode tab spacing D. Based on similar reasons, the length of the cutting track of the electrode tab cutter 1211a (i.e., the cutting length of the electrode tab cutter 1211a to the electrode 200) can also be controlled, thereby controlling the width d of the electrode tab 210 formed by cutting. When the required rotation speed of the rotating shaft 130 is different from the rotation speed of the roller 110 corresponding to the designed tape running speed of the pole piece 200, since the roller 110 can rotate relative to the rotating shaft 130, the roller 110 driven by the pole piece 200 can rotate relative to the ultrasonic knife roller 121 and the auxiliary roller 122, so that the pole piece 200 can continue to be transported forward and the die-cutting process can proceed normally.

[0121] In this embodiment, when there is a difference between the rotation speed of the ultrasonic knife roller 121 and the auxiliary roller 122 and the rotation speed of the over roller 110, the over roller 110 can rotate relative to the ultrasonic knife roller 121 and the auxiliary roller 122 driven by the pole piece 200, and the pole piece 200 can be continuously transported forward, so that the die-cutting process can still proceed normally. On this basis, the rotation speed of the rotating shaft 130 can be flexibly controlled to achieve control of the rotation speed of the ultrasonic knife roller 121 and the auxiliary roller 122, and then the width d and the distance D between the pole tabs 210 that are die-cut can be controlled. Therefore, when the pole piece die-cutting mechanism 100 of this embodiment is used in a die-cutting machine, the pole tabs 210 of the required width and the distance D between the pole tabs of the required size can be processed according to the design requirements, and the pole piece die-cutting mechanism 100 has good process compatibility and applicability.

[0122] In the pole piece die cutting mechanism 100 disclosed herein, the number of the cutting structures 120 is not limited to Figure 1 The two shown in the figure may also be one. The two cutting structures 120 may be implemented by the implementation method described in any of the above embodiments, and the two cutting structures 120 may be the same or different. As an example, the number of cutting structures 120 is one, and one side of the pole piece 200 is die-cut, and accordingly, one end of the pole piece 200 is protruding with a pole ear 210. As an example, Figure 1 As shown, there are two cutting structures 120, which are respectively arranged on both sides of the roller 110, so that both sides of the pole piece 200 are die-cut simultaneously. Accordingly, pole ears 210 are protruding at both ends of the produced pole piece 200.

[0123] The embodiment of the present application further provides a die-cutting machine, comprising: a conveying mechanism and a pole piece die-cutting mechanism 100 described in any of the embodiments above, the conveying mechanism is used to convey the pole piece 200, and the pole piece die-cutting mechanism 100 is located downstream of the conveying mechanism. The beneficial effects of the die-cutting machine are the same as the beneficial effects of the pole piece die-cutting mechanism 100 described above.

[0124] An embodiment of the present application also provides a battery production line, including: a die-cutting machine described in any of the embodiments above, and the beneficial effects of the battery production line are the same as the beneficial effects of the pole piece die-cutting mechanism 100 described above.

[0125] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0126] In the implementation mode of the present application, Figures 1 to 4As shown, the present application proposes a pole piece die-cutting mechanism 100, comprising: two rotating shafts 130, a first roller 110a, a second roller 110b and a cutting structure 120. The two rotating shafts 130 are distributed up and down, parallel to each other and arranged opposite to each other, and the two ends of the two rotating shafts 130 are respectively rotatably connected with two opposite support plates 160. A driver 150 is fixedly mounted on one of the support plates 160, and the driver 150 is connected to the two rotating shafts 130 through a belt transmission mechanism to provide rotational power to the two rotating shafts 130 at the same time, so that the two rotating shafts 130 rotate synchronously in opposite directions.

[0127] The first roller 110a and the second roller 110b are respectively arranged on two rotating shafts 130 through bearings, and a first passage for the pole piece 200 to pass through is formed between the two rollers, so that a part of the pole piece 200 can pass between the first roller 110a and the second roller 110b. The first roller 110a and the second roller 110b can rotate with the corresponding rotating shaft 130, and can also rotate relative to the corresponding rotating shaft 130 driven by the pole piece 200. The first roller 110a is located above the second roller 110b.

[0128] Two cutting structures 120 are provided, and the two cutting structures 120 are respectively arranged on both sides of the two rollers 110. The cutting structure 120 includes an ultrasonic knife roller 121 and an auxiliary roller 122. The ultrasonic knife roller 121 is arranged on the second rotating shaft 130b and can rotate with the second rotating shaft 130b. The axial end surface of the first end of the ultrasonic knife roller 121 contacts the axial end surface of the second roller 110b. A second channel for the pole piece 200 to pass through is formed between the ultrasonic knife roller 121 and the auxiliary roller 122, so that the side edge of the pole piece 200 can pass between the ultrasonic knife roller 121 and the auxiliary roller 122. A cutter 1211 is protrudingly provided on the outer circumferential surface of the ultrasonic knife roller 121. The cutter 1211 includes a tab cutter 1211a and a straight-edge cutter 1211b. The straight-edge cutter 1211b is arranged along the circumference of the ultrasonic knife roller 121. The two ends of the straight-edge cutter 1211b are respectively connected to the two ends of the tab cutter 1211a. The cutter 1211 is located at the first end edge of the ultrasonic knife roller 121. From the root of the cutter 1211 to the tip of the cutter 1211, the thickness of the cutter 1211 changes from being equal everywhere to gradually decreasing.

[0129] The auxiliary roller 122 is arranged on the first rotating shaft 130a and can rotate with the first rotating shaft 130a. The axial end surface of the first end of the auxiliary roller 122 contacts the axial end surface of the first roller 110a. The outer circumferential surface of the auxiliary roller 122 is partially recessed corresponding to the cutter 1211 to form a knife avoidance groove structure. The knife avoidance groove structure includes a pole ear-shaped groove 1221a and an annular groove. The two ends of the pole ear-shaped groove 1221a are connected to the annular groove. The pole ear-shaped groove 1221a cooperates with the pole ear cutter 1211a, and the annular groove cooperates with the straight edge cutter 1211b. The knife avoidance groove structure is located at the first end edge of the auxiliary roller 122.

[0130] When the cutter 1211 rotates and cooperates with the knife avoidance groove structure, a gap is formed between the cutter 1211 and the two opposite groove walls on the knife avoidance groove structure. The width w of the gap is greater than or equal to 0.5 mm and less than or equal to 2 mm. The distance between the tip of the cutter 1211 and the groove bottom of the knife avoidance groove structure facing the tip is also greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0131] The pole piece die-cutting mechanism 100 further includes an ultrasonic generator and an ultrasonic transducer. The ultrasonic transducer is connected to the ultrasonic knife roller 121 to transmit ultrasonic vibration to the ultrasonic knife roller 121 .

[0132] like Figure 8 and Fig. 9 As shown, the ultrasonic knife roller 121 may be further provided with a negative pressure chamber 1213 and a plurality of exhaust holes 1212 distributed in an array, the negative pressure chamber 1213 penetrates the ultrasonic knife roller 121 along the axial direction of the ultrasonic knife roller 121, and the exhaust holes 1212 are arranged on the outer circumferential surface of the ultrasonic knife roller 121 and one end thereof penetrates the cavity wall of the negative pressure chamber 1213. The exhaust holes 1212 are connected to the negative pressure chamber 1213 to form a first negative pressure airway. The cross-sectional shape of the negative pressure chamber 1213 in the direction perpendicular to the axial direction of the ultrasonic knife roller 121 may be a circumferentially unclosed arc, and the center of the arc is arranged concentrically with the center of the ultrasonic knife roller 121.

[0133] The pole piece die-cutting mechanism 100 may further include an annular cover 140, and the number of the annular covers 140 is the same as the number of the cutting structures 120. The annular cover 140 is located on the side of the ultrasonic knife roller 121 included in the corresponding cutting structure 120 that faces away from the second roller 110b, and the annular cover 140 is slidably matched with the rotating shaft 130 connected to the corresponding ultrasonic knife roller 121 through a bearing so as not to rotate with the rotating shaft 130 connected to the ultrasonic knife roller 121. The axial end face of the annular cover 140 facing the ultrasonic knife roller 121 is recessed to form a connecting cavity 141, and the connecting cavity 141 is located on the side of the annular cover 140 facing away from the material direction of the pole piece 200. A negative pressure air port 142 is provided on the outer circumferential surface of the ultrasonic knife roller 121, and one end of the negative pressure air port 142 passes through the cavity wall of the connecting cavity 141. The negative pressure air port 142 is connected to the factory exhaust pipe where the pole piece die-cutting mechanism 100 is located, and the connecting cavity 141 is connected to the negative pressure air port 142 to form a second negative pressure air duct.

[0134] During one rotation of the ultrasonic knife roller 121, when the air extraction hole 1212 is on the side of the ultrasonic knife roller 121 facing away from the material feeding direction of the electrode piece 200, the negative pressure chamber 1213 is connected with the connecting chamber 141, so that the gas flows to the factory air extraction pipeline through the air extraction hole 1212, the negative pressure chamber 1213, the connecting chamber 141 and the negative pressure gas port 142 in sequence. When the air extraction hole 1212 is on the side of the ultrasonic knife roller 121 facing the material feeding direction of the electrode piece 200, the connection relationship between the negative pressure chamber 1213 and the connecting chamber 141 is cut off.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A pole piece die cutting mechanism, characterized in that: include: Two rollers are arranged in parallel and opposite to each other, and a portion of the pole piece is passed between the two rollers; The cutting structure comprises an ultrasonic knife roller and an auxiliary roller which are arranged in parallel and opposite to each other, wherein the ultrasonic knife roller and the auxiliary roller are used for allowing the side edge of the pole piece to pass through; the ultrasonic knife roller is coaxially arranged with one of the passing rollers and distributed in sequence along the axis of one of the passing rollers, a cutting knife is protrudingly arranged on the outer circumferential surface of the ultrasonic knife roller, and the ultrasonic knife roller is configured to receive ultrasonic vibrations; the auxiliary roller is coaxially arranged with the other passing roller and distributed in sequence along the axis of the other passing roller, and a knife-avoiding recess is provided on the outer circumferential surface of the auxiliary roller; wherein the ultrasonic knife roller and the auxiliary roller are configured to rotate synchronously in opposite directions, and when the ultrasonic knife roller and the auxiliary roller rotate, the cutting knife rotates and cooperates with the knife-avoiding recess, so that the side edge of the pole piece traveling along the transmission direction is cut to form a pole ear, and the cutting knife does not contact the auxiliary roller.

2. The pole piece die-cutting mechanism according to claim 1, characterized in that: The auxiliary roller is constructed to include a first roller segment and a second roller segment which are coaxially arranged, the first roller segment being located on the side of the second roller segment which is opposite to the passing roller coaxial with the first roller segment, the diameter of the second roller segment being smaller than the diameter of the first roller segment, the outer circumferential surface of the first roller segment and the outer circumferential surface of the second roller segment being connected by a connecting surface, the connecting surface and the outer circumferential surface of the second roller segment jointly define the knife-avoiding recess, and the connecting surface is at an angle to the axial direction of the auxiliary roller.

3. The pole piece die-cutting mechanism according to claim 1, characterized in that: The cutter comprises a tab cutter and a straight-edge cutter, wherein the straight-edge cutter is arranged along the circumference of the ultrasonic knife roller, and two ends of the straight-edge cutter are respectively connected to two ends of the tab cutter; The knife-avoiding recessed portion is a knife-avoiding groove structure formed by removing the portion corresponding to the cutting knife from the outer circumferential surface of the auxiliary roller, and the knife-avoiding groove structure includes a curved groove and a pole-ear-shaped groove. The curved groove is arranged along the circumference of the auxiliary roller, the curved groove cooperates with the straight-edge cutter, the pole-ear-shaped groove cooperates with the pole-ear cutter, and both ends of the pole-ear-shaped groove are connected to the curved groove.

4. The pole piece die-cutting mechanism according to claim 3, characterized in that: The connection between the straight-edge cutter and the tab cutter is smoothly transitioned, and the connection between the curved groove and the tab-shaped groove is smoothly transitioned.

5. The pole piece die-cutting mechanism according to claim 3, characterized in that: The first end of the ultrasonic knife roller is in contact with the coaxial roller, and the straight-edge cutter is arranged at the edge of the first end of the ultrasonic knife roller; The first end of the auxiliary roller is in contact with the axial end surface of the coaxial passing roller, and the curved groove is arranged at the edge of the first end of the auxiliary roller.

6. The pole piece die cutting mechanism according to any one of claims 3 to 5, characterized in that: The knife avoidance groove structure comprises a first groove wall and a second groove wall, and the first groove wall and the second groove wall are arranged opposite to each other along the axial direction of the auxiliary roller. When the cutting knife rotates and cooperates with the knife avoidance groove structure, a gap is formed between the cutting knife and the first groove wall and between the cutting knife and the second groove wall, and the width of the gap is greater than or equal to 0.5 mm and less than or equal to 2 mm.

7. The pole piece die cutting mechanism according to any one of claims 1 to 5, characterized in that: The height of the cutting knife is h, the depth of the knife avoiding recess is H, and 0.5mm≤Hh≤2mm.

8. The pole piece die cutting mechanism according to any one of claims 1 to 5, characterized in that: From the root of the cutter to the tip of the cutter, the thickness of the cutter changes from being equal everywhere to gradually decreasing.

9. The pole piece die cutting mechanism according to any one of claims 1 to 5, characterized in that: The ultrasonic knife roller is provided with a first negative pressure air channel, and the air inlet end of the first negative pressure air channel passes through the outer circumferential surface of the ultrasonic knife roller; The electrode die-cutting mechanism also includes an annular cover, and the number of the annular covers is the same as the number of the cutting structures; the annular cover is located on the side of the ultrasonic knife roller included in the corresponding cutting structure that is opposite to one of the rollers, and the annular cover is fixed by sliding cooperation with the rotating shaft connected to the corresponding ultrasonic knife roller through a first bearing, and the annular cover is provided with a second negative pressure air duct, and the outlet end of the second negative pressure air duct passes through the outer circumferential surface of the annular cover; during one rotation of the ultrasonic knife roller, the inlet end of the first negative pressure air duct is connected to the inlet end of the second negative pressure air duct when the ultrasonic knife roller is on the side opposite to the electrode material feeding direction, and the connection between the outlet end of the first negative pressure air duct and the inlet end of the second negative pressure air duct is cut off when the ultrasonic knife roller is on the side facing the electrode material feeding direction.

10. The pole piece die cutting mechanism according to claim 9, characterized in that: The first negative pressure airway comprises a negative pressure chamber and an air extraction hole, wherein the negative pressure chamber penetrates the ultrasonic knife roller along the axial direction of the ultrasonic knife roller, and the air extraction hole is arranged on the outer circumferential surface of the ultrasonic knife roller and one end of the air extraction hole penetrates the cavity wall of the negative pressure chamber; The second negative pressure air duct includes a connecting cavity and a negative pressure air port. One end of the connecting cavity passes through a side of the annular cover facing the ultrasonic knife roller and is located on a side of the annular cover facing away from the direction of the electrode material. The negative pressure air port is arranged on the outer circumferential surface of the ultrasonic knife roller and one end passes through the cavity wall of the connecting cavity.

11. The pole piece die cutting mechanism according to claim 10, characterized in that: The outer circumferential surface of the ultrasonic knife roller is provided with a plurality of rows of air extraction holes at intervals along its axial direction, and each row of air extraction holes includes a plurality of air extraction holes arranged in sequence at intervals along the circumferential direction of the ultrasonic knife roller.

12. The pole piece die cutting mechanism according to any one of claims 1 to 5, characterized in that: It also includes two rotating shafts arranged in parallel and opposite to each other, the two rotating shafts are configured to rotate synchronously in opposite directions and the speed is controllable, the two rotating shafts correspond one-to-one to the two rollers, the rollers are arranged on the corresponding rotating shafts through second bearings, and the pole pieces travel along the transmission direction to drive the rollers to rotate relative to the rotating shafts.

13. A die-cutting machine, characterized in that: include: A conveying mechanism, used for conveying pole pieces; The pole piece die-cutting mechanism according to any one of claims 1 to 12 is located downstream of the conveying mechanism.

14. A battery production line, characterized in that: include: The die cutting machine of claim 13.

Images