Foil rolling device and method, current collector, pole piece forming method, battery production system and power utilization device

Abstract

The invention relates to a foil rolling device and method, a current collector, a pole piece forming method, a battery production system and a power utilization device.In the rolling process, a rolling mechanism is used for rolling a foil to the needed thickness, and then a rolling mechanism is used for rolling a first blank area of the foil in the tape conveying direction; and the first blank area has extension deformation in the tape conveying direction. The first blank area of the foil corresponds to the tab area of the pole piece, so that the tab area of the pole piece is equivalently extended in advance and has extension deformation quantity in advance during cold press molding of the pole piece, and the probability of wrinkling of a coating area due to excessive extension can be reduced. Besides, the calendaring of the tab area is advanced to the rolling process, and the calendaring mechanism is arranged at the downstream end of the rolling mechanism, so that heat generated in the rolling process can be fully utilized in the calendaring process, and the first blank area of the foil is easy to extend.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to foil rolling apparatus and methods, current collectors, electrode forming methods, battery manufacturing systems, and electrical devices. Background Technology

[0002] In battery manufacturing processes, the tab area of ​​the electrode is typically stretched using an extrusion process during the cold pressing of the coating area. This stretches the tab area to reduce the likelihood of wrinkling caused by excessive stretching of the coating area. However, in traditional manufacturing processes, the tab area is prone to breakage during the extrusion process, leading to reduced product yield and increased manufacturing costs. Summary of the Invention

[0003] Based on this, it is necessary to provide a foil rolling apparatus and method, a current collector, an electrode forming method, a battery production system, and an electrical device to reduce the probability of wrinkling in the coating area of ​​the electrode, reduce the probability of tape breakage during the preparation process, and improve product yield.

[0004] In a first aspect, this application provides a foil rolling apparatus, comprising: a rolling mechanism for rolling foil; and a calendering mechanism located downstream of the rolling mechanism for calendering a first blank area of ​​the foil along the foil's travel direction, wherein the first blank area of ​​the foil corresponds to the tab area of ​​the electrode sheet.

[0005] The aforementioned foil rolling apparatus utilizes a rolling mechanism to roll the foil to the required thickness, and then a calendering mechanism calenders the first blank area of ​​the foil along the tape travel direction, causing the first blank area to undergo elongation deformation in the tape travel direction. Since the first blank area of ​​the foil corresponds to the tab area of ​​the electrode sheet, the tab area of ​​the electrode sheet is essentially elongated in advance during the cold pressing of the electrode sheet, thus having pre-existing elongation deformation, which reduces the probability of wrinkling in the coating area due to excessive elongation. Furthermore, advancing the calendering of the tab area into the rolling process and placing the calendering mechanism downstream of the rolling mechanism allows for full utilization of the heat generated during rolling, facilitating the elongation of the first blank area of ​​the foil. In addition, the elongation loss of the foil during rolling is relatively small, and the calendering of the foil is smoother and more stable, effectively reducing the probability of tape breakage during preparation and improving product yield.

[0006] In some embodiments, the calendering mechanism includes a calendering roll and calendering protrusions protruding from the roll surface of the calendering roll. The calendering protrusions are arranged in a ring around the axis of the calendering roll and are used to abut against a first blank area of ​​the foil when the calendering roll rotates around its own axis. This design, introducing the calendering roll and the calendering protrusions, ensures that the first blank area is stably calendered under the abutment of the calendering protrusions, which is beneficial to further improve the forming yield of the electrode sheet.

[0007] In some embodiments, the calendering protrusions include at least two, and all calendering protrusions are spaced apart along the axial direction of the calendering roll. This design, by introducing multiple calendering protrusions, allows for simultaneous calendering of multiple first blank areas, which is beneficial for improving calendering efficiency.

[0008] In some embodiments, the height of the calender protruding from the calender roll surface is denoted as D, where 3μm≤D≤5μm. This design controls the protrusion height of the calender protrusion to be between 3μm and 5μm, allowing the calender protrusion to better abut against the first blank area, thereby achieving better calendering.

[0009] In some embodiments, the foil rolling apparatus further includes a stretching mechanism located upstream of the rolling mechanism for stretching a first blank area of ​​the foil along the belt travel direction. This design, by introducing the stretching mechanism to pre-stretch the first blank area before rolling, reduces the strength required for subsequent rolling; at the same time, it also reduces the risk of the foil cracking due to excessive rolling.

[0010] In some embodiments, the stretching mechanism includes a stretching roller and stretching protrusions disposed on the roller surface of the stretching roller. The stretching protrusions are arranged in a ring around the axis of the stretching roller and are used to abut against a first blank area of ​​the foil. This design, by introducing the stretching roller and the stretching protrusions, ensures that the first blank area is stably stretched under the abutment of the stretching protrusions, thereby achieving stable pre-stretching.

[0011] In some embodiments, the stretching mechanism further includes a balance roller located on at least one side of the stretching roller along the foil's travel direction. The roller surface of the balance roller and the roller surface of the stretching roller are used for the foil to be wound vertically. This design, by introducing the balance roller, makes it easier to form tension in the first blank area as the foil is wound vertically between the balance roller and the stretching roller, thereby achieving stable stretching of the first blank area.

[0012] In some embodiments, the stretching protrusions include at least two, and all stretching protrusions are spaced apart along the axial direction of the stretching roller. This design, by introducing multiple stretching protrusions, allows for simultaneous stretching of multiple first blank areas, which helps to improve stretching efficiency.

[0013] In some embodiments, the foil rolling apparatus further includes an oil spraying mechanism located upstream of the rolling mechanism for spraying oil onto the surface of the foil. This design, by introducing the oil spraying mechanism to spray oil onto the surface of the foil, increases the lubricity and heat dissipation of the foil surface, thereby ensuring stable rolling operation.

[0014] In some embodiments, the foil rolling apparatus further includes a cleaning mechanism located downstream of the rolling mechanism for cleaning the surface of the rolled foil. This design, through the cleaning mechanism, cleans the surface of the foil, enabling the foil to be stably processed in subsequent operations, which is beneficial for improving the yield of battery fabrication.

[0015] In some embodiments, the foil rolling apparatus further includes an unwinding mechanism located upstream of the rolling mechanism for supplying foil to the rolling mechanism. This design, by introducing the unwinding mechanism, ensures a stable supply of foil for the rolling operation, allowing rolling to continue continuously.

[0016] In some embodiments, the foil rolling apparatus further includes a winding mechanism located downstream of the calendering mechanism. This design allows the calendered foil to be stably wound up via the winding mechanism.

[0017] Secondly, this application provides a foil rolling method, the method comprising the following steps: rolling the foil to achieve a preset thickness; and rolling the first blank area of ​​the rolled foil to form pleats that protrude or recede along the thickness direction of the foil in the first blank area.

[0018] This design, by advancing the rolling of the tab area to after the rolling process, effectively extends the tab area beforehand, giving it pre-existing stretchability. This reduces the likelihood of wrinkling in the coating area due to excessive stretching. Simultaneously, advancing the rolling of the tab area into the foil rolling process fully utilizes the heat generated during rolling and the superior stretchability of the foil compared to the electrode sheet. This facilitates stretching in the first blank area of ​​the foil, effectively reducing the probability of strip breakage during preparation and improving product yield.

[0019] In some embodiments, during the rolling step of the foil, the rolling pressure on the foil surface is controlled at 180T to 220T. This design, controlling the rolling pressure between 180T and 220T, can meet the requirements for foil thinning; at the same time, it can also provide some heat for subsequent calendering, improving the stability of calendering.

[0020] In some embodiments, during the step of calendering the first blank area of ​​the rolled foil, the calendering tension on the foil surface is controlled at 40 N to 60 N. This design, by controlling the calendering tension between 40 N and 60 N, facilitates stable calendering of the first blank area of ​​the foil, thereby ensuring stable battery fabrication.

[0021] Thirdly, this application provides a current collector, prepared using any of the foil rolling apparatus or foil rolling methods described above, comprising: a main body region; and a second blank region, disposed on at least one side of the main body region, having raised or recessed wrinkles along its own thickness direction, the second blank region corresponding to the tab region of the electrode sheet. This design forms wrinkles in the second blank region, providing effective deformation allowance for subsequent cold pressing of the coating area of ​​the electrode sheet, reducing wrinkling during cold pressing of the coating area; simultaneously, it also reduces the risk of strip breakage in the tab region.

[0022] In some embodiments, the pleats extend along the length of the current collector. This design controls the extension of the pleats in the second blank area along the length direction, giving the second blank area an elongated deformation in the length direction, thus providing structural support for subsequent stable cold pressing.

[0023] Fourthly, this application provides an electrode forming method, the method comprising the following steps: providing a current collector, wherein the current collector is one of the above current collectors; coating the main area of ​​the current collector with an active material to obtain a pretreated electrode; and cold pressing the coated area of ​​the pretreated electrode to obtain an electrode.

[0024] With this design and the use of the above current collector, the extrusion process in the cold pressing process can be eliminated, which can reduce the chance of wrinkling in the coating area and the chance of strip breakage in the tab area, thus making the electrode forming process stable.

[0025] Fifthly, this application provides a battery production system, which includes the foil rolling apparatus of any of the above.

[0026] Sixthly, this application provides an electrical device comprising the current collector described above or an electrode prepared by the electrode forming method described above.

[0027] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0029] Figure 1 This is a schematic diagram of the foil rolling apparatus described in some embodiments of this application.

[0030] Figure 2 This is a partial structural diagram of the foil material described in some embodiments of this application.

[0031] Figure 3 This is a schematic diagram of the calendering mechanism described in some embodiments of this application.

[0032] Figure 4 This is a schematic diagram of the tensioning mechanism described in some embodiments of this application.

[0033] Figure 5 The process flow of the foil rolling method described in some embodiments of this application Figure 1 .

[0034] Figure 6 This is a schematic diagram of the current collector structure described in some embodiments of this application.

[0035] Figure 7 The process flow of the foil rolling method described in some embodiments of this application Figure 2 .

[0036] 100. Foil rolling device; 10. Rolling mechanism; 20. Calendering mechanism; 21. Calendering roll; 22. Calendering protrusion; 30. Stretching mechanism; 31. Stretching roll; 32. Stretching protrusion; 33. Balance roll; 40. Oil spraying mechanism; 41. Cleaning mechanism; 42. First threading guide plate; 43. Flattening roll; 44. Second threading guide plate; 45. Deflecting guide roll; 46. Knife finishing roll; 47. Oil extrusion roll; 48. Plate roll; 50. Unwinding mechanism; 60. Rewinding mechanism; 200. Foil; 210. First blank area; 300. Pleated section; 400. Current collector; 410. Main body area; 420. Second blank area. Detailed Implementation

[0037] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0039] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0041] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0042] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0043] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0044] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0045] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0046] Before forming the electrode, the metal foil must first be rolled to the required thickness and then cut into the required size to obtain the required current collector. Generally, the current collector includes a main area and a second blank area. The main area is used to coat the active material to form the coating area of ​​the electrode; the second blank area is not coated with active material to form the tab area of ​​the electrode.

[0047] During the electrode forming process, the current collector typically undergoes coating and cold pressing. In the cold pressing process, the coated area of ​​the electrode is prone to wrinkling due to excessive stretching. Therefore, an extrusion process is usually added to the cold pressing process to stretch the tab area of ​​the electrode to maintain a relatively consistent shape with the coated area. However, the tab area is prone to breakage during extrusion, resulting in severe breakage during cold pressing.

[0048] Based on this, to address the problems of wrinkling in the coating area and breakage in the tab area during traditional cold pressing, this application provides a foil rolling apparatus. The apparatus utilizes a rolling mechanism to roll the foil to the required thickness, and then a calendering mechanism calenders the first blank area of ​​the foil along the tape-running direction, causing the first blank area to undergo elongation deformation in the tape-running direction. Since the first blank area of ​​the foil corresponds to the tab area of ​​the electrode sheet, the tab area of ​​the electrode sheet is essentially elongated in advance during the cold pressing of the electrode sheet, thus having pre-existing elongation deformation, reducing the probability of wrinkling in the coating area due to excessive elongation. Furthermore, by advancing the calendering of the tab area into the rolling process and placing the calendering mechanism downstream of the rolling mechanism, the heat generated during rolling can be fully utilized, facilitating the elongation of the first blank area of ​​the foil. In addition, the elongation loss of the foil during rolling is relatively small, and the calendering of the foil is smoother and more stable, effectively reducing the probability of tape breakage during preparation and improving product yield.

[0049] It should be noted that foil, current collector, and electrode refer to different product forms that occur in different stages of battery production. Foil can be rolled and slit to form current collector, and current collector can be coated, baked, cold-pressed, and slit to form electrode. At this point, the first blank area of ​​the foil, the second blank area of ​​the current collector, and the tab area of ​​the electrode are all corresponding to each other.

[0050] The current collector disclosed in this application can be fabricated into an electrode, which can then be used to fabricate a battery. This battery can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system incorporating the electrical device disclosed in this application can also be used.

[0051] This application provides an electrical device, which can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0052] According to some embodiments of this application, please refer to Figure 1 This application provides a foil rolling apparatus 100, which includes a rolling mechanism 10 and a calendering mechanism 20. The rolling mechanism 10 is used to roll a foil 200, and the calendering mechanism 20 is located downstream of the rolling mechanism 10 and is used to calender a first blank area 210 of the foil 200 along the feeding direction of the foil 200, wherein the first blank area 210 of the foil 200 corresponds to the tab area of ​​the electrode sheet.

[0053] The rolling mechanism 10 is used to roll the foil 200 to the required thickness. Due to the large compression, the pressure used by the rolling mechanism 10 is also relatively large. For example, the pressure of the rolling mechanism 10 on the foil 200 can be controlled between 180 T (tons) and 220 T. Since the structure of the rolling mechanism 10 is not the object of improvement in this embodiment, its specific structure will not be described in detail here.

[0054] The calendering mechanism 20 is located downstream of the rolling mechanism 10 and can calender the rolled foil 200. During the calendering process, the heat generated by the rolling mechanism 10 can be used to calender the first blank area 210 of the foil 200, making it easier to stretch and less prone to breakage. The foil 200 and the electrode sheet refer to different product forms that appear in different processes during battery production. For example, after the foil 200 is rolled and slit, it forms the current collector 400. After the current collector 400 goes through coating, cold pressing, slitting and other processes, it can form the required electrode sheet. Therefore, the correspondence between the first blank area 210 of the foil 200 and the tab area of ​​the electrode sheet can be understood as follows: after going through various processes, the first blank area 210 of the foil 200 can form the tab area of ​​the electrode sheet.

[0055] It should be noted that both "upstream end" and "downstream end" are referred to in terms of the belt feeding direction. For example, the downstream end of the rolling mechanism 10 refers to the end of the rolling mechanism 10 along the belt feeding direction, and the upstream end of the rolling mechanism 10 refers to the end of the rolling mechanism 10 in the opposite direction to the belt feeding direction. Furthermore, the foil material 200 can be of various types, such as, but not limited to, aluminum foil and copper foil. In some specific examples, the foil material 200 is aluminum foil.

[0056] Since the electrode sheet is formed from foil 200 through a series of processes, the elongation rate of foil 200 is better than that of the electrode sheet. For example, when foil 200 is supplied as raw material, its elongation rate can be 4%. After coating and baking, its elongation rate will be reduced by about 1% to 2%, and abnormalities such as pinholes will also cause an increase of about 1% to 2%. At this time, the elongation rate of the electrode sheet in the cold pressing process is lower than that of foil 200 when it is supplied as raw material. Therefore, by advancing the calendering process to the rolling process, the higher elongation rate of foil 200 can be utilized to make the calendering of the first blank area 210 more stable.

[0057] Furthermore, the calendering mechanism 20 only calenders the first blank area 210. Therefore, the first blank area 210 of the foil 200 will have a deformation difference compared to other parts, that is, several wrinkles 300 will be formed in the first blank area 210. These wrinkles 300 can protrude or be recessed along the thickness direction of the foil 200. For details, please refer to [reference needed]. Figure 2 .

[0058] This design brings the calendering of the tab region forward to the rolling process, and positions the calendering mechanism 20 downstream of the rolling mechanism 10. This allows for full utilization of the heat generated during rolling, facilitating the stretching of the first blank area 210 of the foil 200. Furthermore, the elongation loss of the foil 200 during rolling is relatively small, resulting in smoother and more stable calendering. This effectively reduces the probability of strip breakage during preparation and improves product yield.

[0059] Optionally, according to some embodiments of this application, please refer to Figure 3 The calendering mechanism 20 includes a calendering roller 21 and a calendering protrusion 22 protruding from the roller surface of the calendering roller 21. The calendering protrusion 22 is arranged in a ring around the axis of the calendering roller 21. The calendering protrusion 22 is used to abut against the first blank area 210 of the foil 200 when the calendering roller 21 rotates around its own axis.

[0060] The calendering roll 21 is a structure that can rotate around its own axis, and it can be cylindrical. Calendering protrusions 22 are arranged around the calendering roll 21, and they can also be annular. During the calendering process, the calendering protrusions 22 abut against the first blank area 210 of the foil 200, giving the first blank area 210 a certain tension. Thus, during forward transport, the first blank area 210 undergoes corresponding extension; the magnitude of this extension deformation can be determined according to actual process requirements.

[0061] To achieve effective calendering, the rotational speed of the calendering roll 21 and the contact force of the calendering protrusions 22 can be adjusted appropriately. For example, the rotational speed of the calendering roll 21 can be increased to create a speed difference in the first blank area 210 in the belt carrying direction, so that the first blank area 210 is calendered, etc.

[0062] The width of the calendering protrusion 22 along the axial direction of the calendering roll 21 can be less than the width of the first blank area 210, or it can be equal to the width of the first blank area 210. Meanwhile, the number of calendering protrusions 22 can be determined according to the number of first blank areas 210. For example, the number of calendering protrusions 22 and the number of first blank areas 210 can be set one-to-one, so that the calendering mechanism 20 can simultaneously calender multiple first blank areas 210, improving rolling efficiency.

[0063] To verify the effectiveness of this embodiment, the aluminum foil processed by the foil rolling device 100 can be fed into the subsequent electrode forming process, such as coating, baking, cold pressing in the coating area, and eliminating the traditional extrusion process. After verifying 10 rolls, the aluminum foil processed by this foil rolling device 100 showed 0 breakages. In contrast, using traditional processes, such as coating, baking, cold pressing in the coating area, and extrusion, resulted in 5 breakages out of 10 rolls.

[0064] In addition, to facilitate the stable winding of the foil 200 onto the calendering roll 21, the foil rolling apparatus 100 may also include a first threading guide plate 42, which abuts against the side of the foil 200 facing away from the calendering roll 21.

[0065] This design, which introduces calendering roller 21 and calendering protrusion 22, allows the first blank area 210 to be stably calendered under the contact of the calendering protrusion 22, which is beneficial to further improve the forming yield of the electrode sheet.

[0066] Optionally, according to some embodiments of this application, please refer to Figure 3 The calendering protrusions 22 include at least two, and all the calendering protrusions 22 are spaced apart along the axial direction of the calendering roll 21.

[0067] Each calendering protrusion 22 abuts against its corresponding first blank area 210, enabling simultaneous calendering of multiple first blank areas 210. The roller surface between two adjacent calendering protrusions 22 will not cause calendering of the foil 200; that is, during the calendering process, only the first blank area 210 on the foil 200 is calendered, while other parts are not calendered. The spacing between the calendering protrusions 22 can be determined based on the spacing between two adjacent first blank areas 210.

[0068] This design, which introduces multiple calendering protrusions 22, allows for simultaneous calendering of multiple first blank areas 210, thus improving calendering efficiency.

[0069] Optionally, according to some embodiments of this application, please refer to Figure 3 The height of the calendering protrusion 22 protruding from the calendering roll 21 is denoted as D, where 3μm≤D≤5μm.

[0070] The calendering protrusion 22 protrudes from the surface of the calendering roll 21. Its purpose is to ensure that the calendering protrusion 22 can abut against the first blank area 210, and also to prevent the surface of the calendering roll 21 from causing a calendering effect on the foil 200. The protrusion height of the calendering protrusion 22 can be between 3μm and 5μm, for example, but not limited to 3μm, 3.5μm, 4μm, 4.5μm, 5μm, etc.

[0071] This design controls the protrusion height of the calendering protrusion 22 to 3μm~5μm, allowing the calendering protrusion 22 to better abut against the first blank area 210, thereby achieving better calendering.

[0072] Optionally, according to some embodiments of this application, please refer to Figure 1 The foil rolling apparatus 100 also includes a stretching mechanism 30, which is located at the upstream end of the rolling mechanism 10 and is used to stretch the first blank area 210 of the foil 200 along the belt running direction.

[0073] The stretching mechanism 30 stretches the first blank area 210 of the foil 200 along the belt carrying direction, so that the first blank area 210 can also undergo tensile deformation. The stretching mechanism 30 is located at the upstream end of the rolling mechanism 10, indicating that the first blank area 210 is stretched before rolling, which can provide pre-stretching for subsequent rolling.

[0074] The number of stretching mechanism 30 and rolling mechanism 20 can be one or more. When the number of stretching mechanism 30 and rolling mechanism 20 can be multiple, all stretching mechanisms 30 are located at the upstream end of rolling mechanism 10, and all rolling mechanisms 20 are located at the downstream end of rolling mechanism 10.

[0075] This design, with the introduction of a stretching mechanism 30, pre-stretches the first blank area 210 before rolling, which reduces the strength of subsequent rolling; at the same time, it also reduces the risk of the foil 200 cracking due to excessive rolling.

[0076] Optionally, according to some embodiments of this application, please refer to Figure 4 The stretching mechanism 30 includes a stretching roller 31 and a stretching protrusion 32 disposed on the roller surface of the stretching roller 31. The stretching protrusion 32 is arranged in a ring around the axis of the stretching roller 31 and is used to abut against the first blank area 210 of the foil 200.

[0077] The stretching roller 31 is a structure that can rotate around its own axis, and it can be cylindrical. A stretching protrusion 32 is arranged around the stretching roller 31, and it can also be annular. During the stretching process, the stretching protrusion 32 abuts against the first blank area 210 of the foil 200, giving the first blank area 210 a certain tension. Thus, during forward transport, the first blank area 210 undergoes corresponding stretching; the magnitude of the stretching deformation can be determined according to actual process requirements.

[0078] To achieve effective stretching, the rotational speed of the stretching roller 31 and the contact force of the stretching protrusion 32 can be adjusted appropriately. For example, the rotational speed of the stretching roller 31 can be increased to create a speed difference in the first blank area 210 in the belt carrying direction, so that the first blank area 210 is stretched.

[0079] The width of the stretching protrusion 32 along the axial direction of the stretching roller 31 can be less than the width of the first blank area 210, or it can be equal to the width of the first blank area 210. Meanwhile, the number of stretching protrusions 32 can be determined according to the number of first blank areas 210. For example, the number of stretching protrusions 32 and the number of first blank areas 210 can be set one-to-one, so that the stretching mechanism 30 can stretch multiple first blank areas 210 simultaneously, improving rolling efficiency.

[0080] This design, by introducing the stretching roller 31 and the stretching protrusion 32, allows the first blank area 210 to be stably stretched under the contact of the stretching protrusion 32, thus achieving stable pre-stretching.

[0081] Optionally, according to some embodiments of this application, please refer to Figure 1 The stretching mechanism 30 also includes a balance roller 33, which is located on at least one side of the stretching roller 31 along the conveying direction of the foil 200. The roller surface of the balance roller 33 and the roller surface of the stretching roller 31 are used for the foil 200 to be wound up and down.

[0082] The balancing roller 33 can be located upstream of the stretching roller 31 or downstream of the stretching roller 31; in some examples, the two balancing rollers 33 are located at opposite ends of the stretching roller 31. The foil 200 is wound vertically between the balancing roller 33 and the stretching roller 31. For example, when the balancing roller 33 is upstream of the stretching roller 31, the foil 200 can be wound first on the upper surface of the balancing roller 33 and then on the lower surface of the stretching roller 31; or, first on the lower surface of the balancing roller 33 and then on the upper surface of the stretching roller 31. When the balancing roller 33 is downstream of the stretching roller 31, the foil 200 can be wound first on the upper surface of the stretching roller 31 and then on the lower surface of the balancing roller 33; or, first on the lower surface of the stretching roller 31 and then on the upper surface of the balancing roller 33.

[0083] Of course, if the two balance rollers 33 are located on both sides of the stretch roller 31, the foil 200 can first be wound around the upper surface of one of the balance rollers 33, then around the lower surface of the stretch roller 31, and then around the upper surface of the other balance roller 33; or, the foil 200 can first be wound around the lower surface of one of the balance rollers 33, then around the upper surface of the stretch roller 31, and then around the lower surface of the other balance roller 33.

[0084] This design, with the introduction of the balance roller 33, allows the foil 200 to be wound between the balance roller 33 and the stretching roller 31, making it easier to form tension in the first blank area 210, thereby achieving stable stretching of the first blank area 210.

[0085] Optionally, according to some embodiments of this application, please refer to Figure 4 The stretching protrusions 32 include at least two, and all the stretching protrusions 32 are spaced apart along the axial direction of the stretching roller 31.

[0086] Each stretching protrusion 32 abuts against its corresponding first blank area 210, enabling simultaneous stretching of multiple first blank areas 210. The roller surface between two adjacent stretching protrusions 32 will not stretch the foil 200; that is, during the stretching process, only the first blank area 210 on the foil 200 is stretched, while other parts are not stretched. The spacing between the stretching protrusions 32 can be determined based on the spacing between two adjacent first blank areas 210.

[0087] This design, which introduces multiple stretching protrusions 32, allows for simultaneous stretching of multiple first blank areas 210, thus improving stretching efficiency.

[0088] Optionally, according to some embodiments of this application, please refer to Figure 1 The foil rolling apparatus 100 also includes an oil spraying mechanism 40, which is located upstream of the rolling mechanism 10 and is used to spray oil onto the surface of the foil 200.

[0089] During the rolling process, friction occurs between the rolling mechanism 10 and the foil 200, causing deformation of the entire surface of the foil 200. To address this, an oil spraying mechanism 40 is installed upstream of the rolling mechanism 10 to increase lubrication of the foil 200 surface and reduce friction. Simultaneously, the sprayed oil cools the surface of the foil 200, reducing some of the heat generated during the rolling process.

[0090] The oil spraying mechanism 40 can spray oil on only one surface of the foil 200, or it can spray oil on both the upper and lower surfaces of the foil 200 simultaneously. For example, one oil spraying pipe can be located above the foil 200 and spray oil on the upper surface of the foil 200, while the other oil spraying pipe can be located below the foil 200 and spray oil on the lower surface of the foil 200. Of course, oil spraying mechanisms 40 can also be provided on the upper and lower sides of the foil 200 respectively.

[0091] In addition, to reduce the impact of oil on the rolling mechanism 10, an oil squeezing roller 47 can be provided. The oil squeezing roller 47 abuts against the rolling roller in the rolling mechanism 10 to transfer the oil on the surface of the rolling roller.

[0092] This design incorporates an oil spraying mechanism 40 to spray oil onto the surface of the foil 200, increasing the lubricity and heat dissipation of the foil 200 surface and ensuring stable rolling operation.

[0093] Optionally, according to some embodiments of this application, please refer to Figure 1 The foil rolling apparatus 100 also includes a cleaning mechanism 41, which is located at the downstream end of the rolling mechanism 10 and is used to clean the surface of the rolled foil 200.

[0094] The cleaning mechanism 41 is located downstream of the rolling mechanism 10 and cleans the surface of the rolled foil 200. For example, before rolling, the oil spraying mechanism 40 sprays oil on the surface of the foil 200. After rolling, the oil on the surface of the foil 200 needs to be cleaned to reduce the oil content on the surface of the foil 200, thereby reducing the chance of subsequent coating powder shedding. Of course, the cleaning mechanism 41 can also clean the dust or debris on the surface of the foil 200.

[0095] The cleaning mechanism 41 can perform various cleaning methods, including using a brush or electrostatic dust roller to clean the surface of the foil 200; or using a blower to clean the surface of the foil 200. In some examples, the cleaning mechanism 41 blows the surface of the foil 200 to reduce the oil content on the surface of the foil 200. Furthermore, the cleaning mechanism 41 can clean only one surface of the foil 200, or it can clean both surfaces of the foil 200 simultaneously.

[0096] This design, through the cleaning mechanism 41, cleans the surface of the foil 200, enabling the foil 200 to be stably operated in subsequent processes, which is beneficial to improving the yield of battery manufacturing.

[0097] Optionally, according to some embodiments of this application, please refer to Figure 1 The foil rolling apparatus 100 also includes an unwinding mechanism 50, which is located upstream of the rolling mechanism 10 and is used to provide foil 200 to the rolling mechanism 10.

[0098] The unwinding mechanism 50 refers to the equipment used to release the foil 200, which may include an unwinding roller. To facilitate the stable transmission of the foil 200 to the rolling mechanism 10, the foil rolling device 100 may also include a deflector roller 45, a precision roller 46, and a second threading guide plate 44 located at the downstream end of the unwinding mechanism 50, so that the foil 200 is transmitted stably.

[0099] This design introduces an unwinding mechanism 50 to provide foil 200 for stable rolling operations, enabling continuous rolling.

[0100] Optionally, according to some embodiments of this application, please refer to Figure 1 The foil rolling apparatus 100 also includes a winding mechanism 60, which is located at the downstream end of the calendering mechanism 20.

[0101] The winding mechanism 60 refers to the equipment for winding the calendered foil 200, which may include a winding roller. After the foil 200 is calendered by the calendering mechanism 20, the winding roller can use its own rotation to wind the foil 200 onto the winding roller to form a roll structure.

[0102] In addition, a flattening roller 43 can be provided between the winding mechanism 60 and the calendering mechanism 20 to flatten the portion of the foil 200 except for the first blank area 210.

[0103] This design allows the rolled foil 200 to be stably wound up via the winding mechanism 60.

[0104] According to some embodiments of this application, please refer to Figure 5 This application provides a foil rolling method, which includes the following steps:

[0105] S100: The foil 200 is rolled to achieve a preset thickness.

[0106] S200, the first blank area 210 of the rolled foil 200 is rolled to form a pleated or recessed portion 300 in the first blank area 210 of the foil 200 along the thickness direction of the foil 200.

[0107] In step S100, the foil 200 is rolled to make it thinner. Taking aluminum foil as an example, after rolling, its preset thickness can be 5μm~20μm. Of course, the preset thickness can also be determined according to the actual process requirements.

[0108] In step S200, after the first blank area 210 is rolled, it will have a deformation difference with other parts of the foil 200, resulting in the formation of wrinkles 300 in the first blank area 210. The wrinkles 300 can be raised or recessed along the thickness direction of the foil 200, thus providing deformation allowance for the subsequent cold pressing process of the electrode sheet, so that the deformation of the coating area and the tab area of ​​the electrode sheet remains relatively consistent, reducing the probability of wrinkling in the coating area and also reducing the probability of breakage in the tab area.

[0109] It should be noted that the foil rolling method in this example can also use the foil rolling apparatus 100 in any of the above embodiments.

[0110] This design, by advancing the calendering of the tab area after rolling, effectively extends the tab area in advance, giving it pre-existing stretchability. This reduces the likelihood of wrinkling in the coating area due to excessive stretching. Simultaneously, advancing the calendering of the tab area into the foil 200 rolling process allows full utilization of the heat generated during rolling and the superior stretchability of the foil 200 compared to the electrode sheet. This facilitates the stretching of the first blank area 210 of the foil 200, effectively reducing the probability of strip breakage during preparation and improving product yield.

[0111] According to some embodiments of this application, optionally, in the step of rolling the foil 200, the rolling pressure on the surface of the foil 200 is controlled to be 180 T ~ 220 T.

[0112] The rolling pressure can be between 180 T and 220 T. For example, the rolling pressure can be, but is not limited to, 180 T, 190 T, 200 T, 210 T, 220 T, etc.

[0113] This design controls the rolling pressure between 180 T and 220 T, which can meet the thinning requirements of 200 foil; at the same time, it can also provide some heat for subsequent rolling, improving the stability of rolling.

[0114] According to some embodiments of this application, optionally, in the step of calendering the first blank area 210 of the rolled foil 200, the calendering tension on the surface of the foil 200 is controlled to be 40 N ~ 60 N.

[0115] Calendering tension refers to the force applied along the conveyor belt direction to the first blank area 210 of the foil 200, causing the first blank area 210 of the foil 200 to be calendered. Calendering tension can be achieved using a calendering roller 21, adjusting the contact force between the calendering roller 21 and the foil 200, as well as the rotational speed of the calendering roller 21. Furthermore, calendering tension can be tested using existing tension testing equipment.

[0116] The rolling tension can be between 40 N and 60 N, for example, but not limited to 40 N, 45 N, 50 N, 55 N, 60 N, etc.

[0117] This design controls the rolling tension between 40 N and 60 N, which facilitates stable rolling of the first blank area 210 of the foil 200, thus ensuring stable battery fabrication.

[0118] According to some embodiments of this application, please refer to Figure 6 This application provides a current collector 400, which is prepared using a foil rolling apparatus 100 or a foil rolling method as described above, and includes a main body region 410 and a second blank region 420. The second blank region 420 is disposed on at least one side of the main body region 410 and has pleats 300 that protrude or recede along its own thickness direction. The second blank region 420 is used to correspond to the tab region of the electrode sheet.

[0119] The current collector 400 refers to the metal structure used to support the active material and transfer electrons outward. It is formed from foil 200 through a series of processes, such as rolling, calendering, and slitting, to obtain a current collector 400 with the correct dimensions. The current collector 400 is then used to obtain an electrode sheet with the correct dimensions through processes such as coating, baking, and cold pressing. The material of the current collector 400 can vary depending on the polarity of the electrode sheet. For example, in a positive electrode sheet, the current collector 400 is generally made of aluminum, while in a negative electrode sheet, it is generally made of copper.

[0120] The wrinkle portion 300 refers to the structure formed by the protrusions or depressions in the second blank area 420. The presence of the wrinkle portion 300 causes the second blank area 420 to have a certain deformation along the length of the current collector 400. In this way, during cold pressing, the extension deformation of the coating area of ​​the electrode can be relatively consistent with the pre-deformation of the tab area, effectively reducing the probability of wrinkling in the coating area. Among them, the main body area 410 of the current collector 400 corresponds to the coating area of ​​the electrode, and the second blank area 420 of the current collector 400 corresponds to the tab area of ​​the electrode.

[0121] Furthermore, the size of the protrusions or depressions in the folded portion 300 can be determined according to actual process requirements. For example, half of the width of the current collector 400 can be taken, and the second blank area 420 can be straightened to create a depression on the surface of the main body area 410. In this case, the depression depth of the main body area 410 can be controlled to be above 2mm.

[0122] This design creates a wrinkled portion 300 in the second blank area 420, providing an effective deformation allowance for the subsequent cold pressing of the coating area of ​​the electrode sheet, reducing wrinkling during cold pressing of the coating area; at the same time, it also reduces the risk of strip breakage in the tab area.

[0123] Optionally, according to some embodiments of this application, please refer to Figure 6 The folded portion 300 extends along the length direction of the current collector 400.

[0124] The second blank area 420 of the current collector 400 is formed corresponding to the first blank area 210 of the foil 200, as detailed in the reference. Figure 2 and Figure 6 During the calendering process, the first blank area 210 of the foil 200 is subjected to an elongation force along the conveying direction, so that the wrinkled portion 300 of the second blank area 420 extends partially along the length direction of the current collector 400.

[0125] This design controls the folds 300 of the second blank area 420 to extend along the length direction, so that the second blank area 420 has an extension deformation in the length direction, providing structural support for subsequent stable cold pressing.

[0126] According to some embodiments of this application, please refer to Figure 7 This application provides a method for forming an electrode sheet, the method comprising the following steps:

[0127] S300, providing a current collector 400, wherein the current collector 400 is one or more current collectors 400;

[0128] S400, the main body region 410 of the current collector 400 is coated with an active material to obtain a pretreated electrode.

[0129] S500: Cold press the coating area of ​​the pretreated electrode to obtain the electrode.

[0130] In step S400, during the coating process, the corresponding active material is coated onto the main body region 410 of the current collector 400 to form the coating area of ​​the pretreated electrode. After coating, the current collector 400 can be sent to an oven for baking to evaporate the solvent in the active material.

[0131] In step S500, when cold-pressing the coated area of ​​the pretreated electrode, it is not necessary to compress the tab area of ​​the pretreated electrode. The coated area of ​​the pretreated electrode refers to the structure formed by coating the main body area 410 of the current collector 400 with active material, while the tab area of ​​the pretreated electrode is formed by the second blank area 420 of the current collector 400. The pretreated electrode refers to an electrode that has not undergone cold pressing or similar operations; the structures of the two are or are substantially the same.

[0132] With this design, using the above current collector 400, the extrusion process in the cold pressing process can be eliminated, which can reduce the chance of wrinkling in the coating area and the chance of strip breakage in the tab area, thus making the electrode forming process stable.

[0133] According to some embodiments of this application, this application provides a battery production system, which includes the foil rolling apparatus 100 of any of the above.

[0134] According to some embodiments of this application, this application provides an electrical device comprising an electrode sheet prepared by the above-mentioned current collector 400 or the above-mentioned electrode sheet forming method.

[0135] According to some embodiments of this application, this application provides a foil rolling method. During the rolling process, a calendering mechanism 20 is added. The calendering mechanism 20 includes a calendering roll 21 and calendering protrusions 22 protruding from the roll surface of the calendering roll 21. After rolling, the calendering protrusions 22 are used to calender the first blank area 210 of the foil 200. Thus, during the rolling process, a large amount of frictional heat is released from the foil 200. In the incompletely cooled state, the elongation of the foil 200 is 3% higher than in the cooled state, making it easier to stretch and less prone to breakage. After the foil 200 is rolled, it can undergo slitting, precision cutting, and packaging processes before being transported to the battery coating workshop for coating and cold pressing processes; the cold pressing process eliminates the extrusion process. The foil 200 can be aluminum foil.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A foil rolling device, characterized by comprising: The foil rolling device comprises: a rolling mechanism (10) for rolling a foil (200); a calendering mechanism (20) located at a downstream end of the rolling mechanism (10) for calendering a first blank area (210) of the foil (200) along a running direction of the foil (200), wherein the first blank area (210) of the foil (200) corresponds to a tab area of a pole piece.

2. The foil rolling apparatus according to claim 1, characterized by The calendering mechanism (20) comprises a calendering roller (21) and calendering protrusions (22) protruding from a roller surface of the calendering roller (21), the calendering protrusions (22) are annularly arranged around an axis of the calendering roller (21), and the calendering protrusions (22) are used for abutting against the first blank area (210) of the foil (200) when the calendering roller (21) rotates around its axis.

3. The foil rolling apparatus according to claim 2, wherein The calendering protrusions (22) comprise at least two, and all the calendering protrusions (22) are arranged at intervals along the axis direction of the calendering roller (21).

4. The foil rolling apparatus according to claim 2, wherein The protrusion height of the calendering protrusions (22) from the roller surface of the calendering roller (21) is denoted as D, wherein 3μm≤D≤5μm.

5. The foil rolling apparatus according to claim 1, wherein The foil rolling device further comprises a stretching mechanism (30) located at an upstream end of the rolling mechanism (10) for stretching the first blank area (210) of the foil (200) along the running direction.

6. The foil rolling apparatus according to claim 5, wherein The stretching mechanism (30) comprises a stretching roller (31) and stretching protrusions (32) provided on a roller surface of the stretching roller (31), the stretching protrusions (32) are annularly arranged around an axis of the stretching roller (31), and the stretching protrusions (32) are used for abutting against the first blank area (210) of the foil (200).

7. The foil rolling apparatus according to claim 6, wherein The stretching mechanism (30) further comprises a balance roller (33) located at at least one side of the stretching roller (31) along the running direction of the foil (200), a roller surface of the balance roller (33) and a roller surface of the stretching roller (31) are used for winding the foil (200) thereon.

8. The foil rolling apparatus according to claim 6, wherein The stretching protrusions (32) comprise at least two, and all the stretching protrusions (32) are arranged at intervals along the axis direction of the stretching roller (31).

9. The foil rolling apparatus according to any one of claims 1 to 8, characterized in that, The foil rolling device further comprises an oil spraying mechanism (40) located at an upstream end of the rolling mechanism (10) for spraying oil on a surface of the foil (200); and / or, The foil rolling device further comprises a cleaning mechanism (41) located at a downstream end of the rolling mechanism (10) for cleaning a surface of the rolled foil (200).

10. The foil rolling apparatus according to any one of claims 1 to 8, characterized in that, The foil rolling device further comprises an unwinding mechanism (50) located at an upstream end of the rolling mechanism (10) for providing the rolling mechanism (10) with the foil (200); and / or, The foil rolling device further comprises a winding mechanism (60) located at a downstream end of the calendering mechanism (20).

11. A method of rolling foil material, characterized by, The method comprises the following steps: rolling the foil (200) to make the thickness of the foil (200) reach a preset thickness; calendering the first blank area (210) of the rolled foil (200) to form a wrinkle (300) protruding or recessed along the thickness direction of the foil (200) in the first blank area (210) of the foil (200).

12. The method of claim 11, wherein, In the step of rolling the foil (200), the rolling pressure on the surface of the foil (200) is controlled to be 180 T ~ 220 T.

13. The foil rolling method according to claim 11 or 12, characterized in that, In the step of calendering the first blank area (210) of the rolled foil (200), the calendering tension on the surface of the foil (200) is controlled to be 40 N ~ 60 N.

14. A current collector (400) produced using the foil rolling apparatus according to any one of claims 1 to 10 or the foil rolling method according to any one of claims 11 to 13, characterized by Comprise: a main body area (410); a second blank area (420) provided on at least one side of the main body area (410) and having a wrinkle (300) protruding or recessed along the thickness direction of the second blank area (420), the second blank area (420) being used to correspond to the tab area of the pole piece.

15. The current collector (400) of claim 14, wherein, The wrinkle (300) extends along the length direction of the current collector (400).

16. A pole piece forming method characterized by, The method comprises the following steps: providing a current collector (400), wherein the current collector (400) is the current collector (400) of claim 14 or 15; coating the main body area (410) of the current collector (400) with active material to obtain a pretreated pole piece; cold pressing the coated area of the pretreated pole piece to obtain a pole piece.

17. A battery production system characterized by comprising: The battery production system comprises the foil rolling device of any one of claims 1-10.

18. An electrical device, comprising: The power utilization device comprises the current collector (400) of claim 14 or 15 or the pole piece formed by the pole piece forming method of claim 16.

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