Pole extension device and pole piece manufacturing equipment

Abstract

The present application discloses a pole piece extension device and pole piece manufacturing equipment. The pole piece extension device includes a first roller and a second roller. The first roller includes a first body and a protrusion, the protrusion being provided on the outer peripheral surface of the first body and extending along the circumference of the first body. The second roller includes a second body and a groove, the groove being provided on the outer peripheral surface of the second body and extending along the circumference of the second body. The first roller and the second roller are arranged in parallel, and a gap is formed between the first roller and the second roller for the pole piece to pass through. The protrusion corresponds to the position of the groove, and the protrusion is used to press the empty foil area of the pole piece to cause the empty foil area to plastically deform. The technical solution provided by the present application can improve the production efficiency of the battery.

Description

Technical Field

[0001] The present application relates to the field of battery production technology, and in particular to a pole piece extension device and pole piece manufacturing equipment. Background Art

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0003] In the development of battery technology, how to improve battery production efficiency is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] The present application provides a pole piece extension device and pole piece manufacturing equipment, which can improve the production efficiency of batteries.

[0005] In the first aspect, the present application provides a pole piece extension device, comprising: a first roller, comprising a first body and a protrusion, the protrusion being provided on the outer peripheral surface of the first body and extending along the circumferential direction of the first body; a second roller, comprising a second body and a groove, the groove being provided on the outer peripheral surface of the second body and extending along the circumferential direction of the second body; wherein, the first roller and the second roller are arranged in parallel, and a gap is formed between the first roller and the second roller for the pole piece to pass through, the protrusion corresponds to the position of the groove, and the protrusion is used to press the empty foil area of the pole piece to cause the empty foil area to plastically deform.

[0006] In the above scheme, when the electrode passes between the first roller and the second roller, the convex portion is used to act on the empty foil area to apply a certain pressure to the empty foil area, and the groove supports the empty foil area to ensure that the empty foil area is plastically deformed under safe conditions, thereby achieving the effect of flattening the wrinkles of the empty foil area and extending the empty foil area, thereby reducing the risk of electrode breakage in the subsequent cold pressing process, increasing the production capacity of the electrode, and thereby improving the production efficiency of the battery.

[0007] According to some embodiments of the present application, the protrusion and the groove are complementary in shape.

[0008] In the above solution, the hollow foil area is plastically deformed under the pressure of the protrusion to fit the surface of the groove, thereby effectively flattening the wrinkles of the hollow foil area and extending the hollow foil area.

[0009] According to some embodiments of the present application, the surface of the protrusion transitions to the outer circumference of the first body in a circular arc, and the surface of the groove transitions to the outer circumference of the second body in a circular arc.

[0010] In the above scheme, the surface of the protrusion transitions to the outer peripheral surface of the first body in a circular arc, and the surface of the groove transitions to the outer peripheral surface of the second body in a circular arc, which can avoid the situation where the empty foil area is damaged due to a large height difference with the coating area of the electrode after being subjected to the downward pressure tension of the protrusion, thereby ensuring the safety of the electrode.

[0011] According to some embodiments of the present application, a dimension of the protrusion in the length direction of the first roller is W, satisfying 20 mm ≤ W ≤ 80 mm.

[0012] In the above solution, the width of the protrusion is greater than or equal to 20 and less than or equal to 80 mm, so as to correspond to the width of the empty foil area on the electrode of different specifications.

[0013] According to some embodiments of the present application, a dimension of the protrusion protruding from the outer circumferential surface of the first body is H, which satisfies 2mm≤H≤9mm.

[0014] In the above scheme, since the elongation rate of the empty foil area required for each specification of electrode is different, the height range of the protrusion is limited. Different protrusion heights represent different elongation rates obtained after the empty foil area is crushed by the protrusion. The larger the protrusion height, the greater the elongation rate.

[0015] According to some embodiments of the present application, there are multiple protrusions, and the multiple protrusions are distributed at intervals along the axial direction of the first body; there are multiple grooves, and the multiple grooves are distributed at intervals along the axial direction of the second body, and the grooves correspond one-to-one to the protrusions.

[0016] In the above scheme, by providing multiple protrusions and grooves to simultaneously roll multiple empty foil areas on the electrode, the efficiency of solving the wrinkle and extension problems of the empty foil areas is effectively improved, the output of the electrode is increased, and thus the production efficiency of the battery is improved.

[0017] According to some embodiments of the present application, the pole piece extension device further includes: a heating part for heating the empty foil area.

[0018] In the above scheme, by heating the empty foil area, the residual stress and tensile strength of the empty foil area are reduced, and the flexibility is increased, so as to ensure that when the protrusions and grooves act on the empty foil area, the empty foil area can plastically deform and stretch under a smaller downward tension, so that the wrinkles of the empty foil area are effectively flattened, thereby reducing the risk of pole piece breakage in the subsequent cold pressing process and improving the production capacity of the pole piece.

[0019] According to some embodiments of the present application, the heating part is arranged inside the first body and / or the second body.

[0020] In the above scheme, when the pole piece passes between the first roller and the second roller, the heating part inside the first body and / or the second body can heat the empty foil area to improve the efficiency of stretching and stretching the empty foil area. At the same time, since the heating part is arranged inside the first body and / or the second body, the pole piece extension device can be made compact in structure and have a low space occupancy rate, thereby avoiding space waste.

[0021] According to some embodiments of the present application, the heating portion is independent of the first roller and the second roller.

[0022] In the above scheme, since the heating part is independent of the first roller and the second roller, on the one hand, the empty foil area can be heated independently to ensure the heating effect of the empty foil area; on the other hand, the first roller and the second roller do not need to be provided with a heating part, so the structure of the first roller and the second roller is simple, which effectively reduces the manufacturing cost of the first roller and the second roller.

[0023] According to some embodiments of the present application, along the running direction of the pole piece, the heating portion is arranged upstream of the first roller and the second roller.

[0024] In the above scheme, when the electrode passes between the first roller and the second roller, the empty foil area of the electrode is heated by the heating part, so that the residual stress and tensile strength of the empty foil area are reduced and the flexibility is increased, so that when the protrusions and grooves act on the empty foil area, the empty foil area can plastically deform and stretch under a smaller downward tension, so that the wrinkles in the empty foil area are effectively flattened, thereby reducing the risk of electrode breakage in the subsequent cold pressing process and improving the production capacity of the electrode.

[0025] According to some embodiments of the present application, the heating part is a magnetic induction heating part or a far-infrared heating part.

[0026] According to some embodiments of the present application, the pole piece extending device further includes: a third roller, the third roller being located on a side of the second roller away from the first roller and being used to support the second roller.

[0027] In the above solution, the third roller is a support roller, which is used to support the weight of the second roller and the first roller, so that the first roller can stably apply downward tension to the empty foil area to ensure effective plastic deformation of the empty foil area.

[0028] According to some embodiments of the present application, one of the first roller and the second roller is a driving roller, and the other is a driven roller.

[0029] In one embodiment of the above scheme, the first roller is an active roller and the second roller is a driven roller. Specifically, the first roller actively rotates to provide downward tension to the empty foil area, while the second roller passively rotates to provide support for the empty foil area. In another embodiment, the first roller is a driven roller and the second roller is an active roller. Specifically, the second roller actively rotates to provide support for the empty foil area and drives the first roller to rotate, thereby providing downward tension to the empty foil area.

[0030] According to some embodiments of the present application, the pole piece extending device further includes: an adjusting mechanism connected to the active roller, for adjusting the tension applied by the active roller to the pole piece.

[0031] In the above solution, the tension applied by the active roller to the pole piece is adjusted by the adjustment mechanism, so that the elongation rate of the empty foil area can be adjusted to meet the requirements of pole pieces of different specifications.

[0032] In the second aspect, the present application also provides a pole piece manufacturing device, comprising: a pole piece extending device as described in any embodiment of the first aspect; a cold pressing device for cold pressing the pole piece, wherein the cold pressing device is arranged downstream of the pole piece extending device along the tape running direction of the pole piece.

[0033] In the above scheme, after the empty foil area of the electrode is extended and wrinkled by the electrode extension device, the risk of the electrode breaking during cold pressing in the cold pressing device can be reduced, thereby improving the production capacity of the electrode.

[0034] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 Schematic diagram of a pole piece extension device in some embodiments of the present application;

[0037] Figure 2 A three-dimensional diagram of a pole piece extension device in some embodiments of the present application;

[0038] Figure 3 for Figure 1 Enlarged view of point A in the middle;

[0039] Figure 4 Schematic diagram of protrusions and grooves in some embodiments of the present application;

[0040] Figure 5 Schematic diagrams of protrusions and grooves in other embodiments of the present application;

[0041] Figure 6 Schematic diagram of arc-edged right-angled protrusions and grooves in some embodiments of the present application;

[0042] Figure 7 Schematic diagram of semi-straight-edge rounded-corner protrusions and grooves in some embodiments of the present application;

[0043] Figure 8 Schematic diagram of straight-edged and rounded-corner protrusions and grooves in some embodiments of the present application;

[0044] Figure 9 Schematic diagram of straight-edged and right-angled protrusions and grooves in some embodiments of the present application;

[0045] Figure 10 Schematic diagram of a pole piece in some embodiments of the present application;

[0046] Figure 11 This is a three-dimensional diagram of the pole piece extension device in other embodiments of the present application.

[0047] Icons: 10-first roller; 11-first body; 12-protrusion; 20-second roller; 21-second body; 22-groove; 30-heating part; 40-third roller; 120-straight section; 121-arc section; 122-first section; 123-second section; 124-arc section; 125-straight edge section; 126-third section; 127-fourth section; 100-pole piece; 101-empty foil area; 102-coating area. DETAILED DESCRIPTION

[0048] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0050] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0051] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0052] The term "and / or" in this application simply describes an association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0053] The term "multiple" used in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two (including two) groups, and "multiple sheets" refers to more than two (including two) sheets.

[0054] In this application, the battery referred to herein refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack.

[0055] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The current collector uncoated with the positive active material layer protrudes from the current collector coated with the positive active material layer, and the current collector uncoated with the positive active material layer serves as the positive electrode tab. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The current collector uncoated with the negative active material layer protrudes from the current collector coated with the negative active material layer, and the current collector uncoated with the negative active material layer serves as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon or silicon, among others. To ensure high current flow without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together. The separator provides electronic insulation, separating adjacent positive and negative electrode tabs to prevent short circuits. The separator has numerous micropores that allow the free passage of electrolyte ions and is highly permeable to lithium ions, making it virtually impervious to lithium ions. Separators can be made of materials such as PP (polypropylene) or PE (polyethylene).

[0056] The preparation process of the electrode usually includes slurrying, coating, cold pressing, and tab die-cutting. The coating process involves applying the well-mixed active material to the current collector, so that the current collector has a coated area coated with an active material layer and an empty foil area that is not coated with an active material layer. The empty foil area is used as a tab after processing (for example, after the tab die-cutting process). Generally, in order to improve the coating efficiency, a roller coating process is often used. Roller coating uses a rotating roller as a carrier of the active material. The active material forms a wet film of a certain thickness on the surface of the roller. The roller then contacts the current collector during rotation, and the active material is coated on the surface of the current collector. The cold pressing process is to roll the electrode with the active material attached through a cold pressing device. On the one hand, it makes the coated material more compact, improves the energy density, and ensures the consistency of thickness. On the other hand, it will further control dust and humidity.

[0057] In the development of battery technology, how to improve battery production efficiency is a technical problem that needs to be solved urgently.

[0058] As mentioned above, the use of a roller coating process can improve coating efficiency. However, pole pieces coated using the roller coating process are prone to breaking during the cold pressing process. The inventors have discovered that the reason for pole piece breaking is that during the coating process, the coated area is subject to roller pressure, while the bare foil area is not. This results in different elongation rates between the coated and bare foil areas, causing wrinkles in the bare foil area. This makes the pole piece prone to breaking during the cold pressing process, affecting the pole piece's production capacity.

[0059] In view of this, in order to reduce the risk of electrode breakage during the cold pressing process and to increase the production capacity of the electrode, the inventors, after in-depth research, have designed a electrode stretching device comprising a first roller and a second roller. The first roller comprises a first body and a protrusion, the protrusion being provided on the outer peripheral surface of the first body and extending along the circumference of the first body. The second roller comprises a second body and a groove, the groove being provided on the outer peripheral surface of the second body and extending along the circumference of the second body. The first roller and the second roller are arranged in parallel, and the electrode passes between the first roller and the second roller for conveying, and the protrusion and the groove respectively correspond to the opposite sides of the empty foil area of the electrode in the thickness direction. When the electrode passes between the first roller and the second roller, the empty foil area will be plastically deformed under the joint action of the protrusion and the groove to flatten the wrinkles of the empty foil area, and the empty foil area will be stretched so that the stretching rate of the empty foil area is consistent or nearly consistent with the stretching rate of the coated area.

[0060] In the above scheme, the first body and the second body correspond to opposite sides of the coated area of the electrode in the thickness direction, and the protrusion and the groove correspond to opposite sides of the bare foil area of the electrode in the thickness direction. When the electrode is conveyed between the first roller and the second roller, the protrusion protruding from the first body acts on the bare foil area, applying a certain amount of pressure to the bare foil area. In conjunction with the support provided by the groove, the bare foil area is plastically deformed under safe conditions, achieving the effect of flattening wrinkles and stretching the bare foil area. This reduces the risk of electrode breakage in the subsequent cold pressing process, increases electrode production capacity, and thus improves battery production efficiency.

[0061] The electrode stretching device disclosed in the embodiments of this application is used to remove wrinkles and stretch the bare foil area of the electrode. The electrode stretching device can be part of an electrode manufacturing device, which can also include a cold pressing device. After the electrode is acted upon by the electrode stretching device, it can be cold pressed by the cold pressing device to complete the cold pressing process of the electrode.

[0062] For some embodiments of this application, please see Figures 1-4 , Figure 1 This is a schematic diagram of a pole piece extension device in some embodiments of the present application. Figure 2 This is a three-dimensional diagram of the pole piece extension device in some embodiments of the present application. Figure 3 for Figure 1 The enlarged view of point A in the middle. Figure 4Schematic diagram of the protrusion 12 and the groove 22 in some embodiments of the present application.

[0063] The electrode sheet extension device includes a first roller 10 and a second roller 20. The first roller 10 includes a first body 11 and a protrusion 12. The protrusion 12 is provided on the outer circumference of the first body 11 and extends along the circumference of the first body 11. The second roller 20 includes a second body 21 and a groove 22. The groove 22 is provided on the outer circumference of the second body 21 and extends along the circumference of the second body 21. The first roller 10 and the second roller 20 are arranged in parallel. A gap is formed between the first roller 10 and the second roller 20 for the electrode sheet 100 to pass through. The protrusion 12 corresponds to the groove 22 in position and is used to press against the empty foil area 101 of the electrode sheet 100, causing the empty foil area 101 to plastically deform.

[0064] The first roller 10 is positioned opposite the second roller 20. The central axes of the first and second rollers 10, 20 are parallel to each other, with a gap between them allowing the electrode sheet 100 to pass through and travel. The first and second rollers 10, 20 can be positioned with the first roller 10 positioned above the second roller 20 or below it. Alternatively, this embodiment of the present application uses the first roller 10 positioned above the second roller 20 as an example.

[0065] The first body 11 is cylindrical, with its central axis being the central axis of the first roller 10. A protrusion 12 is provided on the outer circumference of the first body 11 and is disposed around the first body 11. The protrusion 12 corresponds to the bare foil area 101 of the electrode 100, while the first body 11 corresponds to the coated area 102 of the electrode 100. That is, when the electrode 100 passes through the first roller 10 and the second roller 20, the protrusion 12 acts on the surface of the bare foil area 101 of the electrode 100, while the first body 11 acts on the surface of the coated area 102 of the electrode 100.

[0066] The second body 21 is cylindrical, with its central axis being the central axis of the second roller 20. A groove 22 is recessed into the outer circumference of the second body 21 and is disposed around the second body 21. The groove 22 corresponds to the surface of the blank foil area 101 facing away from the protrusion 12, and the second body 21 corresponds to the surface of the coated area 102 facing away from the first body 11.

[0067] Plastic deformation means that when the protrusions 12 and the grooves 22 act on the empty foil area 101 , the wrinkles of the empty foil area 101 can be flattened and the empty foil area 101 can be extended.

[0068] In the above scheme, when the electrode 100 passes between the first roller 10 and the second roller 20, the protrusion 12 is used to act on the empty foil area 101, applying a certain downward pressure tension to the empty foil area 101, and cooperating with the groove 22 to support the empty foil area 101, so as to ensure that the empty foil area 101 is plastically deformed under safe conditions, thereby achieving the effect of flattening the wrinkles of the empty foil area 101 and extending the empty foil area 101, thereby reducing the risk of the electrode 100 breaking in the subsequent cold pressing process, improving the production capacity of the electrode 100, and thus improving the production efficiency of the battery.

[0069] According to some embodiments of the present application, the protrusion 12 and the groove 22 have complementary shapes.

[0070] “The protrusion 12 and the groove 22 are complementary in shape” means that the protrusion 12 protrudes toward the groove 22. When the empty foil area 101 is located between the protrusion 12 and the groove 22, any position on the surface of the protrusion 12 acts on the empty foil area 101, which can make the empty foil area 101 fit into the surface of the groove 22.

[0071] In the above solution, the empty foil area 101 is plastically deformed under the downward pressure of the protrusion 12 to fit the surface of the groove 22, thereby effectively flattening the wrinkles of the empty foil area 101 and extending the empty foil area 101.

[0072] According to some embodiments of the present application, Figure 4 and Figure 5 , Figure 5 Schematic diagrams of protrusions 12 and grooves 22 in other embodiments of the present application.

[0073] The surface of the protrusion 12 transitions to the outer circumference of the first body 11 in an arc shape, and the surface of the groove 22 transitions to the outer circumference of the second body 21 in an arc shape.

[0074] "The surface of the protrusion 12 transitions to the outer circumference of the first body 11 in an arc shape" means that the protrusion 12 protrudes from the surface of the first body 11, and the height difference between the two is compensated by the arc structure. Figure 7 、 Figure 8 as well as Figure 9 In the figure, the surface of the protrusion 12 and the outer peripheral surface of the first body 11 are not arc transitions, but can be regarded as right-angle transitions. By comparison Figure 4 、 Figure 5 、 Figure 7 、 Figure 8 as well as Figure 9 , one can intuitively understand the “arc transition between the surface of the protrusion 12 and the outer peripheral surface of the first body 11”.

[0075] Similarly, “the surface of the groove 22 transitions to the outer circumference of the second body 21 in an arc shape” means that the groove 22 is sunken into the surface of the second body 21 , and the height difference between the two is compensated by the arc structure.

[0076] In the above scheme, the surface of the protrusion 12 transitions to the outer peripheral surface of the first body 11 in a circular arc, and the surface of the groove 22 transitions to the outer peripheral surface of the second body 21 in a circular arc, which can avoid the empty foil area 101 being damaged due to a large height difference with the coating area of the electrode 100 after being subjected to the downward pressure tension of the protrusion 12, thereby ensuring the safety of the electrode 100.

[0077] In some embodiments, the shapes of the protrusion 12 and the groove 22 can be various, including but not limited to: arc-edge rounded corner type, isolated right-angled corner type, isolated wide-angled corner type, semi-straight edge rounded corner type, straight edge rounded corner type or straight edge right-angle type, etc.

[0078] in, Figure 4 The protrusion 12 and groove 22 shown are of arc-edge and rounded corner type. The arc edge refers to the transition between the protrusion 12 and the surface of the first body 11 through an arc edge, and the transition between the groove 22 and the surface of the second body 21 through an arc edge; the rounded corner refers to the arc-shaped surface of the protrusion 12 facing the groove 22, and the arc-shaped surface of the groove 22 facing the protrusion 12.

[0079] Figure 5 The protrusion 12 and the groove 22 shown are of the wide-angle type. Taking the protrusion 12 as an example, the wide-angle type means that the protrusion 12 and the first body 11 are transitioned by an arc edge, and the protrusion 12 includes a straight section 120 and an arc section 121, and the straight section 120 is connected to the arc edge by the arc section 121.

[0080] See Figure 6 , Figure 6 Schematic diagram of arc-edged right-angled protrusions 12 and grooves 22 in some embodiments of the present application. Figure 6 The protrusion 12 and groove 22 shown are of the isolated right-angle type. Taking the protrusion 12 as an example, the arc-edge right angle means that the protrusion 12 and the first body 11 are transitioned through an arc edge, and the protrusion 12 includes a first section 122 and a second section 123. The first section 122 and the second section 123 are both straight sections, and the first section 122 is connected to the arc edge through the second section 123.

[0081] See Figure 7 , Figure 7 Schematic diagram of semi-straight-edge rounded protrusions 12 and grooves 22 in some embodiments of the present application. Figure 7 The protrusion 12 and groove 22 shown are semi-straight-edge rounded-corner types. Taking the protrusion 12 as an example, the protrusion 12 is arc-shaped, and the edge of the protrusion 12 is directly connected to the surface of the first body 11, and there is no arc-shaped structure (arc edge) transition between the two.

[0082] See Figure 8 , Figure 8 Schematic diagram of a straight-edged and rounded-corner protrusion 12 and a groove 22 in some embodiments of the present application. Figure 8The protrusion 12 and groove 22 shown are straight-edged and rounded-corner types. Taking the protrusion 12 as an example, the protrusion 12 includes an arc segment 124 and a straight-edged segment 125. The straight-edged segment 125 is located at both ends of the arc segment 124, and the arc segment 124 is connected to the surface of the first body 11 through the straight-edged segment 125.

[0083] See Figure 9 , Figure 9 Schematic diagram of the straight-edge and right-angled protrusions 12 and grooves 22 in some embodiments of the present application. Figure 9 The protrusion 12 and groove 22 shown are straight-sided and right-angled. Taking the protrusion 12 as an example, the protrusion 12 includes a third section 126 and a fourth section 127. The fourth section 127 is located at both ends of the third section 126, and the fourth section 127 and the third section 126 are perpendicular to each other. The third section 126 is connected to the surface of the first body 11 through the fourth section 127, and the fourth section 127 and the surface of the first body 11 are perpendicular to each other.

[0084] In some embodiments, when the surface of the protrusion 12 transitions to the outer surface of the first body 11 in an arc, that is, when the corner between the protrusion 12 and the first body 11 is rounded, the size of the rounded corner is R (see Figure 4 and Figure 5 ), satisfying 1 mm ≤ R ≤ 7 mm. In some embodiments, R may be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, or 7 mm.

[0085] In the above scheme, a chamfer is provided between the protrusion 12 and the first body 11 to accommodate the pole piece 100 with an insulating layer provided between the empty foil area 101 and the coated area 102. By limiting the size range of the chamfer to correspond to the size of the insulating layer, damage to the insulating layer is avoided when the protrusion 12 presses down the empty foil area 101.

[0086] According to some embodiments of the present application, a dimension of the protrusion 12 in the length direction of the first roller 10 is W, which satisfies 20 mm ≤ W ≤ 80 mm.

[0087] The dimension of the protrusion 12 in the length direction of the first roller 10 is the width of the protrusion 12. The width of the protrusion 12 corresponds to the width of the empty foil area 101, so that when the protrusion 12 acts on the empty foil area 101, it can act on any position of the empty foil area 101. The width of the empty foil area 101 of different specifications of the electrode 100 varies. Generally, the width of the empty foil area 101 of the existing electrode 100 of different specifications ranges from 20mm to 80mm. By limiting the range of the width W of the protrusion 12, it can accommodate electrode 100 of different specifications. Correspondingly, the dimension of the groove 22 in the length direction of the second roller 20 is consistent with the width of the protrusion 12.

[0088] In the above embodiment, the width of the protrusion 12 is greater than or equal to 20 mm and less than or equal to 80 mm to correspond to the width of the empty foil area 101 on the electrode 100 of different specifications. The width (W) of the protrusion 12 can be 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, or 80 mm.

[0089] In some embodiments, to accommodate an empty foil area 101 with a width of 20 mm, the width (W) of the protrusion 12 may be 20 mm; to accommodate an empty foil area 101 with a width of 30 mm, the width (W) of the protrusion 12 may be 30 mm; to accommodate an empty foil area 101 with a width of 50 mm, the width (W) of the protrusion 12 may be 50 mm; to accommodate an empty foil area 101 with a width of 60 mm, the width (W) of the protrusion 12 may be 60 mm.

[0090] According to some embodiments of the present application, Figure 4 and Figure 5 The dimension of the protrusion 12 protruding from the outer peripheral surface of the first body 11 is H, which satisfies 2mm≤H≤9mm.

[0091] The dimension of the protrusion 12 protruding from the outer circumference of the first body 11 is the height of the protrusion 12, and the height of the protrusion 12 corresponds to the elongation of the empty foil area 101. Because the elongation of the empty foil area 101 required for each type of pole piece 100 is different, protrusions 12 of different heights correspond to empty foil areas 101 with different elongations. The higher the height of the protrusion 12, the greater the elongation of the empty foil area 101 after the protrusion 12 acts on the empty foil area 101. Correspondingly, the dimension of the groove 22 recessed from the outer circumference of the second body 21 is consistent with the height of the protrusion 12.

[0092] In the above solution, because each specification of electrode 100 requires a different elongation of the hollow foil area 101, the height range of the protrusion 12 is limited. Different heights of the protrusion 12 represent different elongations of the hollow foil area 101 after being pressed by the protrusion 12. The higher the height of the protrusion 12, the greater the elongation. In some embodiments, the width (H) of the protrusion 12 can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, or 9mm.

[0093] According to some embodiments of this application, please combine Figure 1 、 Figure 2 as well as Figure 10 , Figure 10 Schematic diagram of the pole piece 100 in some embodiments of the present application.

[0094] There are multiple protrusions 12 , which are spaced apart along the axial direction of the first body 11 . There are multiple grooves 22 , which are spaced apart along the axial direction of the second body 21 , and the grooves 22 correspond to the protrusions 12 one by one.

[0095] like Figure 10 In order to improve the coating efficiency, a stripe coating method is used for coating through a roller coating process to form a plurality of spaced empty foil areas 101 on the electrode 100. In a subsequent process, the electrode 100 is cut into multiple pieces by cutting.

[0096] There are multiple protrusions 12 and grooves 22 to correspond to multiple empty foil areas 101 on the current collector.

[0097] In the above scheme, by providing multiple protrusions 12 and grooves 22, multiple empty foil areas 101 on the electrode 100 can be rolled simultaneously, thereby effectively improving the efficiency of solving the wrinkle and extension problems of the empty foil areas 101, increasing the output of the electrode 100, and thus improving the production efficiency of the battery.

[0098] According to some embodiments of this application, see Figure 2 The electrode extension device also includes a heating unit 30, which is used to heat the empty foil area 101.

[0099] The heating portion 30 is a component capable of generating heat to heat the empty foil area 101 .

[0100] When the protrusions 12 and the grooves 22 are simply used to act on the empty foil area 101, the applied pressure is large. Since the empty foil area 101 itself has limited elongation, the tolerance (tensile strength at break) of the empty foil area 101 is greatly reduced. In addition, the residual stress of the foil after calendering is large, which is not conducive to the elimination of wrinkles and is likely to cause tape breakage during the subsequent cold pressing process of the electrode 100. In particular, when the empty foil area 101 itself has pinholes, concave and convex points, rotten edges and other inevitable problems caused by transportation, simply using the protrusions 12 and the grooves 22 to roll the empty foil area 101 will not have a good elongation effect on the empty foil area 101. For this reason, the empty foil area 101 is heated by the heating unit 30. After the empty foil area 101 is heated, the tensile strength is reduced and the flexibility is increased. When the protrusions 12 and the grooves 22 act, the empty foil area 101 is easily stretched under a smaller tension, reducing the risk of tape breakage.

[0101] In the above scheme, by heating the empty foil area 101, the residual stress and tensile strength of the empty foil area 101 are reduced, and the flexibility is increased, so as to ensure that when the protrusion 12 and the groove 22 act on the empty foil area 101, the empty foil area 101 can plastically deform and stretch under a smaller downward tension, so that the wrinkles of the empty foil area 101 are effectively flattened, thereby reducing the risk of the pole piece 100 breaking in the subsequent cold pressing process and improving the production capacity of the pole piece 100.

[0102] According to some embodiments of the present application, Figure 2 The heating part 30 is disposed inside the first body 11 and / or the second body 21 .

[0103] “The heating portion 30 is disposed inside the first body 11 and / or the second body 21 ” means that the heating portion 30 is disposed inside the first body 11 ; or, the heating portion 30 is disposed inside the second body 21 ; or, the heating portion 30 is disposed inside the first body 11 and the second body 21 respectively.

[0104] In some embodiments, the heating portion 30 may be an internal heating roller disposed in the first body 11 and / or the second body 21 , and the internal heating roller may be a resistance heating structure.

[0105] "The heating portion 30 is disposed inside the first body 11 and / or the second body 21" can also be understood as that the heating portion 30 is a partial structure of the first roller 10; or the heating portion 30 is a partial structure of the second roller 20; or the first roller 10 and the second roller 20 respectively have a heating portion 30; that is, when the electrode 100 passes through the first roller 10 and the second roller 20, the first roller 10 and / or the second roller 20 can heat the empty foil area 101. In some embodiments, the heating method of the first roller 10 and / or the second roller 20 can be: steam heating roller heating, thermal oil heating roller heating, electric heating tube heating roller heating or resistance wire heating roller heating technology, among which steam heating roller heating, thermal oil heating roller heating, electric heating tube heating roller heating or resistance wire heating roller heating technology are existing conventional roller heating technologies, and therefore are not described in detail in the embodiments of this application.

[0106] In the above scheme, when the electrode 100 passes between the first roller 10 and the second roller 20, the heating part 30 located in the first body 11 and / or the second body 21 heats the protrusion 12 on the first body 11 or the groove 22 on the second body 21 to heat the empty foil area 101, thereby improving the efficiency of stretching and stretching the empty foil area 101 (when the inner walls of the first body 11 and the second body 21 are respectively provided with the heating part 30, the first roller 10 and the second roller 20 can heat the empty foil area 101 at the same time, so that the empty foil area 101 has a better heating effect). At the same time, since the heating part 30 is arranged inside the first body 11 and / or the second body 21, the electrode extension device can be made compact in structure and have a low space occupancy rate, thereby avoiding space waste.

[0107] According to other embodiments of the present application, see Figure 11 , Figure 11 3D images of the electrode stretching device in some other embodiments of the present application. The heating unit 30 is independent of the first roller 10 and the second roller 20.

[0108] “The heating unit 30 is independent of the first roller 10 and the second roller 20” means that the heating unit 30 is an independent component. Figure 11 Two heating units 30 are shown as an example, and the two heating units 30 are located above the empty foil area 101 to heat the corresponding empty foil area 101. In other embodiments, the heating unit 30 may be located below the empty foil area 101.

[0109] In the above scheme, since the heating section 30 is independent of the first roller 10 and the second roller 20, on the one hand, it can independently heat the empty foil area 101 to ensure the heating effect on the empty foil area 101; on the other hand, the first roller 10 and the second roller 20 do not need to be provided with the heating section 30, so the first roller 10 and the second roller 20 have a simple structure, which effectively reduces the manufacturing cost of the first roller 10 and the second roller 20.

[0110] According to some embodiments of the present application, along the running direction of the pole piece 100 , the heating unit 30 is disposed upstream of the first roller 10 and the second roller 20 .

[0111] “The heating section 30 is arranged upstream of the first roller 10 and the second roller 20 ” means that the electrode 100 first passes through the heating section 30 and then passes between the first roller 10 and the second roller 20 , that is, the empty foil area 101 is first heated by the heating section 30 and then pressed by the protrusions 12 and the grooves 22 .

[0112] In the above scheme, when the electrode 100 passes between the first roller 10 and the second roller 20, the empty foil area 101 of the electrode 100 is heated by the heating part 30, so that the residual stress and tensile strength of the empty foil area 101 are reduced and the flexibility is increased, so that when the protrusion 12 and the groove 22 act on the empty foil area 101, the empty foil area 101 can plastically deform and stretch under a smaller downward tension, so that the wrinkles of the empty foil area 101 are effectively flattened, thereby reducing the risk of the electrode 100 breaking in the subsequent cold pressing process and improving the production capacity of the electrode 100.

[0113] According to some embodiments of the present application, the heating portion 30 is a magnetic induction heating portion 30 or a far-infrared heating portion 30 .

[0114] The magnetic induction heating unit 30 utilizes the principle of electromagnetic induction heating to heat the empty foil area 101. The far-infrared heating unit 30 utilizes infrared light and heat radiation to heat the empty foil area 101. Since the heating methods of the magnetic induction heating unit 30 or the far-infrared heating unit 30 are both conventional heating methods, they will not be described in detail in this application.

[0115] According to some embodiments of this application, see Figure 1 、 Figure 2 as well as Figure 11 The pole piece extending device further includes a third roller 40 , which is located on the side of the second roller 20 away from the first roller 10 and is used to support the second roller 20 .

[0116] The central axis of the third roller 40 is parallel to the central axis of the second roller 20 . Generally, the first roller 10 is located above the second roller 20 , and the second roller 20 is located above the third roller 40 .

[0117] The third roller 40 is a support roller, which is used to support the weight of the second roller 20 and the first roller 10, so that the first roller 10 can stably apply downward tension to the empty foil area 101 to ensure that the empty foil area 101 is effectively plastically deformed.

[0118] According to some embodiments of the present application, one of the first roller 10 and the second roller 20 is a driving roller, and the other is a driven roller.

[0119] The active roller is a roller that can actively rotate, and the driven roller is a roller that rotates following the active roller. Figure 2 ,exist Figure 2 In the embodiment, the first roller 10 is an active roller and has a driving shaft. Figure 11 ,exist Figure 11 In the embodiment, the second roller 20 is an active roller and has a driving shaft.

[0120] In the above scheme, in one case, the first roller 10 is an active roller and the second roller 20 is a driven roller. That is, the first roller 10 actively rotates to provide downward pressure tension to the empty foil area 101, and the second roller 20 passively rotates to provide support for the empty foil area 101. In another case, the first roller 10 is a driven roller and the second roller 20 is an active roller. That is, the second roller 20 actively rotates to provide support for the empty foil area 101 and drives the first roller 10 to rotate, so that the first roller 10 provides downward pressure tension to the empty foil area 101.

[0121] According to some embodiments of the present application, the pole piece extending device further includes: an adjusting mechanism (not shown in the figure), connected to the active roller, for adjusting the tension applied by the active roller to the pole piece 100.

[0122] In the above solution, the tension applied by the active roller to the pole piece 100 is adjusted by the adjustment mechanism, so that the elongation of the empty foil area 101 can be adjusted to meet the requirements of pole pieces 100 of different specifications.

[0123] According to some embodiments of the present application, a pole piece manufacturing apparatus is further provided, comprising the pole piece stretching device and a cold pressing device described above. The cold pressing device is used to cold press the pole piece 100 to complete the cold pressing process. The cold pressing device is disposed downstream of the pole piece stretching device along the tape feed direction of the pole piece 100.

[0124] In the above solution, after the empty foil area 101 of the electrode 100 is stretched and wrinkled by the electrode stretching device, the risk of the electrode 100 breaking during cold pressing in the cold pressing device can be reduced, thereby improving the production capacity of the electrode 100.

[0125] According to some embodiments of this application, see Figures 1-4 Some embodiments of the present application provide a pole piece stretching device, which is located upstream of a cold pressing device and is used to stretch and dewrinkle the empty foil area 101 of the pole piece 100. The pole piece stretching device includes a first roller 10, a second roller 20 and a third roller 40 arranged in an upper and lower manner. The pole piece 100 passes through the gap between the first roller 10 and the second roller 20 and is transported. The third roller 40 is a support roller, which supports the second roller 20 to ensure the stability of the first roller 10 and the second roller 20. The first roller 10 is an active roller, which includes a first body 11 and protrusions 12 (the number of the protrusions 12 is three, and the three protrusions 12 are arranged at intervals along the axial direction of the first body 11). The protrusions 12 are provided on the outer peripheral surface of the first body 11 and extend along the circumference of the first body 11. A heating portion 30 is provided inside the first body 11, and the heating portion 30 can heat the first body 11 and the protrusions 12. The second roller 20 is a driven roller and includes a second body 21 and a groove 22. The groove 22 is provided on the outer circumference of the second body 21 and extends circumferentially along the second body 21. The interior of the second body 21 is also provided with a heating portion 30, which can heat the first body 11 and the groove 22. The heating portions 30 in both the first roller 10 and the second roller 20 are electromagnetic heating rollers provided within the first body 11 and the second body 21. Because both the first roller 10 and the second roller 20 have heating portions 30, the bare foil area 101 of the electrode piece 100 can be heated when the electrode piece 100 passes between the first roller 10 and the second roller 20, thereby improving the flexibility of the bare foil area 101. As the electrode piece 100 travels along the tape, the protrusions 12 act on the bare foil area 101, applying a certain downward pressure and rolling it until it aligns with the groove 22, thereby flattening wrinkles and stretching the foil. This reduces the breakage rate of the electrode piece 100 during the cold pressing process. Among them, the shapes of the protrusion 12 and the groove 22 are complementary, and the shapes of the protrusion 12 and the groove 22 are arc-edge rounded. The dimension W of the protrusion 12 in the length direction of the first roller 10 is 40 mm, and the dimension H of the protrusion 12 protruding from the outer peripheral surface of the first body 11 is 4 mm. When the corners between the protrusion 12 and the first body 11 are rounded, the dimension R of the rounded corner is 1 mm.

[0126] According to some embodiments of this application, see Figure 5 and Figure 11. Some embodiments of the present application provide a pole piece stretching device, which is located upstream of a cold pressing device and is used to stretch and dewrinkle the empty foil area 101 of the pole piece 100. The pole piece stretching device includes a first roller 10, a second roller 20 and a third roller 40 arranged up and down. The pole piece 100 passes through the gap between the first roller 10 and the second roller 20 and is transported. The third roller 40 is a support roller, which supports the second roller 20 to ensure the stability of the first roller 10 and the second roller 20. The first roller 10 is a driven roller, which includes a first body 11 and a protrusion 12 (the number of the protrusions 12 is two, and the two protrusions 12 are arranged at intervals along the axial direction of the first body 11). The protrusions 12 are provided on the outer peripheral surface of the first body 11 and extend along the circumference of the first body 11. The second roller 20 is an active roller, which includes a second body 21 and a groove 22. The groove 22 is provided on the outer peripheral surface of the second body 21 and extends along the circumference of the second body 21. The pole piece extension device also includes a heating unit 30, which is a magnetic induction heating unit 30, to heat the empty foil area 101 independently of the first roller 10 and the second roller 20. The heating unit 30 is located upstream of the first roller 10 and the second roller 20 to heat the empty foil area 101 before the pole piece 100 passes through the first roller 10 and the second roller 20, thereby improving the flexibility of the empty foil area 101. In this way, during the tape running of the pole piece 100, the protrusion 12 acts on the empty foil area 101, applying a certain downward pressure tension, and rolling it until it is aligned with the groove 22, thereby achieving the effect of flattening wrinkles and extending the foil, thereby reducing the tape breakage rate of the pole piece 100 during the cold pressing process. Among them, the shapes of the protrusion 12 and the groove 22 are complementary, and the shapes of the protrusion 12 and the groove 22 are arc-edged wide-angle types. The dimension W of the protrusion 12 in the length direction of the first roller 10 is 50 mm, and the dimension H of the protrusion 12 protruding from the outer peripheral surface of the first body 11 is 5 mm. When the corners between the protrusion 12 and the first body 11 are rounded, the dimension R of the rounded corner is 3 mm.

[0127] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A pole piece extension device, located upstream of a cold pressing device, characterized in that: include: A first roller includes a first body and a protrusion, wherein the protrusion is provided on the outer peripheral surface of the first body and extends along the circumference of the first body; a second roller comprising a second body and a groove, wherein the groove is provided on an outer peripheral surface of the second body and extends along a circumferential direction of the second body; The first roller and the second roller are arranged in parallel, and a gap is formed between the first roller and the second roller for the electrode sheet to pass through. The protrusions correspond to the grooves one by one and have corresponding positions. The protrusions are complementary in shape to the grooves. The protrusions are used to press the empty foil area of the electrode sheet so that the empty foil area fits the surface of the groove, causing the empty foil area to plastically deform. The dimension H of the protrusion protruding from the outer circumference of the first body satisfies 2 mm ≤ H ≤ 9 mm; The size of the groove sunken into the outer peripheral surface of the second body is consistent with the value of H.

2. The pole piece extension device according to claim 1, characterized in that: The surface of the protrusion transitions to the outer circumference of the first body in an arc shape, and the surface of the groove transitions to the outer circumference of the second body in an arc shape.

3. The pole piece extension device according to claim 1, characterized in that: The dimension of the protrusion in the length direction of the first roller is W, which satisfies 20 mm ≤ W ≤ 80 mm.

4. The pole piece extension device according to claim 1, characterized in that: There are multiple protrusions, and the multiple protrusions are distributed at intervals along the axial direction of the first body; There are multiple grooves, which are distributed at intervals along the axial direction of the second body, and the grooves correspond to the protrusions one by one.

5. The pole piece extension device according to claim 1, characterized in that: The pole piece extension device further includes: The heating part is used for heating the empty foil area.

6. The pole piece extension device according to claim 5, characterized in that: The heating part is disposed inside the first body and / or the second body.

7. The pole piece extension device according to claim 5, characterized in that: The heating portion is independent of the first roller and the second roller.

8. The pole piece extension device according to claim 7, characterized in that: Along the running direction of the pole piece, the heating portion is arranged upstream of the first roller and the second roller.

9. The pole piece extension device according to claim 7, characterized in that: The heating part is a magnetic induction heating part or a far infrared heating part.

10. The pole piece extension device according to claim 1, characterized in that: The pole piece extension device further includes: The third roller is located on a side of the second roller away from the first roller and is used to support the second roller.

11. The pole piece extension device according to any one of claims 1 to 10, characterized in that: One of the first roller and the second roller is a driving roller, and the other is a driven roller.

12. The pole piece extension device according to claim 11, characterized in that: The pole piece extension device further includes: An adjusting mechanism is connected to the active roller and is used to adjust the tension applied by the active roller to the pole piece.

13. A pole piece manufacturing device, characterized in that: include: The pole piece extension device according to any one of claims 1 to 12; A cold pressing device is used to cold press the pole piece. Along the running direction of the pole piece, the cold pressing device is arranged downstream of the pole piece extending device.

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