Rolling device for flexible battery electrodes

Abstract

The application discloses a rolling device for a flexible battery electrode, and the flexible battery electrode is a fibrous electrode. The rolling device comprises at least two groups of pairs of rollers arranged in sequence along the conveying direction of the fibrous electrode, and is used for rolling the fibrous electrode for multiple times. The at least two groups of pairs of rollers comprise a first group of pairs of rollers and a second group of pairs of rollers. The first group of pairs of rollers comprises a first roller and a second roller, and a first rolling cavity is formed between the first roller and the second roller, and is used for rolling the fibrous electrode for the first time. The second group of pairs of rollers comprises a third roller and a fourth roller, and a second rolling cavity is formed between the third roller and the fourth roller, and is used for rolling the fibrous electrode for the second time. The action direction of the first preset pressure is different from the action direction of the second preset pressure. The application can improve the density of the fibrous electrode, and meanwhile, the original fiber form and flexibility of the fibrous electrode are maintained, so that the use requirement of special-shaped batteries is met.

Description

Technical Field

[0001] This application relates to the field of battery electrode manufacturing, and more specifically, to a rolling device for flexible battery electrodes. Background Technology

[0002] Flexible batteries, due to their advantages such as bendability, foldability, and adaptability, have broad application prospects in wearable devices, flexible displays, and smart healthcare. Unlike the sheet-like electrodes of traditional lithium batteries, some electrodes of flexible batteries are fibrous electrodes. Fiber-like electrodes have good flexibility and deformation capabilities, and can adapt to the complex shape requirements of irregularly shaped batteries.

[0003] Roll forming is one of the core processes in battery electrode forming. Its core function is to apply controllable pressure through rolls to densify loose electrode materials, optimize the electrode microstructure, and improve the mechanical strength and electrochemical performance of the electrode. The roll forming process directly determines the energy density, internal resistance, and cycle life of the battery cell.

[0004] Traditional lithium-ion battery sheet electrode rolling devices typically employ extremely heavy steel rollers, applying high pressure to compact and shape the electrode sheets. However, this traditional rolling device is unsuitable for fibrous electrodes, exhibiting the following significant drawbacks: 1. Poor compatibility between the roll surface of traditional steel rollers and the shape of fibrous electrodes: Since the roll surface of traditional steel rollers is a planar structure, while fibrous electrodes are mostly cylindrical, the roll surface of the planar steel roller cannot fully fit with the fibrous electrode during rolling, resulting in uneven force on the fibrous electrode, which easily causes the fibrous electrode to twist and deform, losing its original fiber shape. 2. Damaged electrode flexibility: Traditional steel rollers are heavy, have high rolling pressure and lack a buffer structure. They are prone to over-compacting the fibrous electrodes during the rolling process, damaging their flexibility indicators such as bending, resulting in the fibrous electrodes after rolling being unable to meet the deformation requirements of flexible batteries. 3. Low production efficiency: Traditional steel rollers are heavy, inconvenient to start, stop and adjust, and require frequent pressure adjustments to avoid electrode damage, resulting in low roller pressing efficiency and making it difficult to meet the needs of large-scale production of fibrous electrodes.

[0005] Therefore, there is an urgent need to develop a dedicated rolling device for flexible battery electrodes to solve the technical problems of poor adaptability of traditional steel roller rolling, damage to electrode flexibility, and electrode deformation, so as to achieve efficient and non-destructive rolling of fibrous electrodes. Summary of the Invention

[0006] The main objective of this application is to provide a rolling device for flexible battery electrodes to solve the technical problems of poor adaptability, easy damage to electrode flexibility and low production efficiency of traditional steel rollers in the prior art. This device can perform low-pressure rolling on fibrous electrodes, which can improve the density of fibrous electrodes while maintaining their original fiber morphology and flexibility, thereby meeting the needs of irregularly shaped batteries.

[0007] To achieve the above objectives, this application provides the following technical solution: A rolling device for a flexible battery electrode, wherein the flexible battery electrode is a fibrous electrode with an initial outer diameter of 0.1–1 mm; the rolling device for the flexible battery electrode includes at least two sets of rollers arranged sequentially along the conveying direction of the fibrous electrode for multiple rolling operations on the fibrous electrode; the at least two sets of rollers include a first set of rollers and a second set of rollers; wherein the first set of rollers includes a first roll and a second roll, and a first rolling chamber is formed between the first roll and the second roll for applying a first preset pressure to the fibrous electrode fed therein for a first rolling operation; the second set of rollers includes a third roll and a fourth roll, and a second rolling chamber is formed between the third roll and the fourth roll for applying a second preset pressure to the fibrous electrode after the first rolling operation for a second rolling operation; the direction of the second preset pressure is different from the direction of the first preset pressure, so that the fibrous electrode is uniformly stressed in the circumferential direction after multiple rolling operations.

[0008] Preferably, the fibrous electrode passes sequentially through the first rolling chamber and the second rolling chamber; and the inner contours of the first rolling chamber and the second rolling chamber are matched with the outer shape of the fibrous electrode to form a circumferential limit on the fibrous electrode.

[0009] Preferably, the rolling speed of the second set of rollers during the second rolling is equal to the rolling speed of the first set of rollers during the first rolling.

[0010] Preferably, the surfaces of the first roll, the second roll, the third roll, and the fourth roll are all provided with roll pressing grooves arranged circumferentially. In the rolling state, the two roll pressing grooves on the first roll and the second roll are connected to each other to form the first roll pressing cavity, and the two roll pressing grooves on the third roll and the fourth roll are connected to each other to form the second roll pressing cavity. The cross-sectional area of ​​the first roll pressing cavity is smaller than the initial cross-sectional area of ​​the fibrous electrode, so that the first roll pressing cavity forms an interference fit with the fibrous electrode during the rolling process, thereby facilitating the application of the first preset pressure to the fibrous electrode. The cross-sectional area of ​​the second roll pressing cavity is smaller than the initial cross-sectional area of ​​the fibrous electrode, so that the second roll pressing cavity forms an interference fit with the fibrous electrode during the rolling process, thereby facilitating the application of the second preset pressure to the fibrous electrode.

[0011] Preferably, the fibrous electrode is in the shape of an elongated cylinder; the inner diameter of the first roller pressing cavity is smaller than the initial outer diameter of the fibrous electrode, so that the fibrous electrode and the first roller pressing cavity form an interference fit, so as to apply the first preset pressure to the fibrous electrode; the inner diameter of the second roller pressing cavity is smaller than the initial outer diameter of the fibrous electrode, so that the fibrous electrode and the second roller pressing cavity form an interference fit, so as to apply the second preset pressure to the fibrous electrode.

[0012] Preferably, the first roll, the second roll, the third roll, and the fourth roll include: a roll-forming layer in direct contact with the fibrous electrode, the roll-forming layer being made of a tough material; and the roll-forming groove being disposed on the roll-forming layer.

[0013] Preferably, the toughening material is silicone, polyurethane, or nitrile rubber.

[0014] Preferably, the first roll, the second roll, the third roll, and the fourth roll further include a roll core, which is covered inside by the roll pressing layer, and the roll core is made of a lightweight material.

[0015] Preferably, the second preset pressure applied to the second set of rollers is equal to the first preset pressure applied to the first set of rollers.

[0016] Preferably, the second preset pressure applied to the second set of rollers is less than the first preset pressure applied to the first set of rollers, so as to form a gradient roller pressure.

[0017] The technical solution provided in this application may include the following beneficial effects: (1) This application uses at least two sets of rollers to roll the fibrous electrode multiple times, thereby improving the density of the fibrous electrode and optimizing its microstructure while avoiding damage to the electrode flexibility and maintaining the integrity of the fiber morphology, thus enhancing the mechanical strength and electrochemical performance of the fibrous electrode. (2) In this application, the two rollers of each pair of rollers form a roller pressing cavity for the fibrous electrode to pass through during rolling. The roller pressing cavity matches the shape of the fibrous electrode, which can achieve precise fit and prevent the fibrous electrode from sliding in the roller pressing cavity, thereby ensuring that it is subjected to uniform force and maintains its original fiber shape. (3) The direction of the first preset pressure applied by the first set of rollers in this application is different from the direction of the second preset pressure applied by the second set of rollers, so that the fibrous electrode can be subjected to pressure from multiple directions in sequence after being rolled at least twice, thereby achieving uniform force in the circumferential direction; compared with the roller pressing method of applying pressure in a single direction in the prior art, this application effectively eliminates the problem of elliptic or flattened deformation of the fibrous electrode cross section caused by applying pressure in a single direction in sequence, so that the fibrous electrode can still maintain an approximately circular cross section shape after being rolled, which is beneficial to maintaining the original structural integrity of the fiber; (4) This application uses multiple rolling presses in different directions to make the density of the fibrous electrode more uniform in all directions, which significantly improves the compaction uniformity of the electrode and the consistency of the product, and reduces the risk of fiber breakage or active material shedding caused by excessive compression in one direction, thereby ensuring the conductivity and cycle stability of the battery. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of a rolling device for a flexible battery electrode according to Embodiment 1 of this application; Figure 2 for Figure 1 A cross-sectional view AA shown when the first and second rolls are not enclosed; Figure 3 for Figure 1 A cross-sectional view AA showing the first and second rolls together; Figure 4 for Figure 1 A cross-sectional view showing the application of a first preset pressure to the fibrous electrode when the first and second rolls are closed; Figure 5 for Figure 1 The BB cross-sectional view shown is shown when the third and fourth rolls are not enclosed. Figure 6 for Figure 1 The BB cross-sectional view shown when the third and fourth rolls are together; Figure 7 for Figure 1 A BB cross-sectional view showing the application of a second preset pressure to the fibrous electrode when the third and fourth rolls are closed; Figure 8 The force diagrams for the fibrous electrode of this application in four directions in Embodiment 1 are shown. Figure 9 This is a schematic diagram of a rolling device for a flexible battery electrode according to Embodiment 2 of this application; Figure 10 This is a schematic diagram of the structure of the rolling mill roll according to Embodiment 3 of this application.

[0019] Explanation of reference numerals in the attached drawings: 1-First set of rollers; 10-Roller groove; 11-First roll; 12-Second roll; 101-First roll chamber; 2-Second set of rollers; 21-Third roll; 22-Fourth roll; 201-Second roll chamber; 3-Fiber electrode; F1-First preset pressure; F2-Second preset pressure. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0023] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0024] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linked," and "socketing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] In recent years, wearable devices and flexible electronic devices have become increasingly popular. However, these devices come in various shapes, and consequently, the batteries used to adapt to them also vary in shape. These irregularly shaped batteries are called irregularly shaped batteries. Wearable devices and flexible electronic devices may be bent or folded during use, requiring the irregularly shaped batteries to maintain their performance and return to their original shape after being bent or folded. Due to their excellent flexibility and deformation capabilities, fibrous electrodes can be adapted to the application scenarios of irregularly shaped flexible batteries, and therefore, they are widely used in irregularly shaped flexible batteries.

[0026] Roll forming is one of the key processes in the production of fibrous electrodes. A key technical challenge limiting the large-scale production of fibrous electrodes is how to improve their density without compromising their flexibility during the rolling process.

[0027] This application provides a rolling device and rolling process for flexible battery electrodes, which is used to roll fibrous electrodes, thereby achieving the technical effect of improving the density of fibrous electrodes without damaging their fiber flexibility.

[0028] The following detailed description of a rolling device and rolling process for a flexible battery electrode according to specific embodiments of this application is provided below.

[0029] This embodiment provides a rolling device and rolling process method for rolling flexible battery electrodes. The flexible battery electrode in this embodiment is a fibrous electrode, such as... Figure 1 As shown, the fibrous electrode in this embodiment is a long cylindrical shape.

[0030] Specifically, the rolling device for the flexible battery electrode in this embodiment includes at least two sets of rollers arranged sequentially along the conveying direction of the fibrous electrode. These at least two sets of rollers are used to roll the fibrous electrode multiple times. By employing at least two sets of rollers to roll the fibrous electrode multiple times, the density of the fibrous electrode is effectively improved and its microstructure optimized, while avoiding damage to the electrode's flexibility and ensuring the integrity of the fiber morphology. This, in turn, enhances the mechanical strength and electrochemical performance of the fibrous electrode.

[0031] Example 1

[0032] The rolling device for the flexible battery electrode in this embodiment includes two sets of rollers arranged sequentially along the conveying direction of the fibrous electrode. The two sets of rollers are used to roll the fibrous electrode twice.

[0033] Accordingly, the rolling process of the flexible battery electrode in this embodiment includes: feeding the fibrous electrode into the space between two sets of rollers for two rolling processes.

[0034] like Figure 1 As shown, the two sets of rollers include a first set of rollers 1 and a second set of rollers 2 arranged sequentially along the conveying direction.

[0035] Specifically, the fibrous electrode is sequentially fed between two sets of rollers for two rolling processes, including: feeding the fibrous electrode 3 between the two rolls of the first set of rollers 1, applying a first preset pressure F1 to the fibrous electrode 3 through the first set of rollers 1 for the first rolling process; feeding the fibrous electrode 3 after the first rolling process between the two rolls of the second set of rollers 2, applying a second preset pressure F2 to the fibrous electrode 3 through the second set of rollers 2 for the second rolling process.

[0036] Specifically, in the first rolling process of this embodiment, the first preset pressure F1 applied by the first set of rollers 1 to the fibrous electrode 3 is preferably 0.5-1 MPa. This first preset pressure is much lower than the rolling pressure applied by traditional steel rollers to lithium battery sheet electrodes. By setting the first preset pressure to be much lower than the rolling pressure of traditional steel rollers to perform the first rolling of the fibrous electrode, the fibrous electrode can be initially densified while maintaining the fiber morphology of the fibrous electrode, thereby ensuring that the flexibility and deformation capability of the fibrous electrode remain unchanged.

[0037] The fibrous electrode 3, after the first rolling process, is fed between the two rolls of the second set of rollers 2. The second set of rollers 2 applies a second preset pressure F2 to the fibrous electrode 3 for a second rolling process. This second rolling process can further improve the uniformity of the density of the fibrous electrode.

[0038] In one specific embodiment of this example, the second preset pressure F2 applied by the second set of rollers 2 to the fibrous electrode 3 is equal to the first preset pressure F1 applied by the first set of rollers 1 to the fibrous electrode 3. Since the first preset pressure is much lower than the rolling pressure of conventional steel rollers, and the second preset pressure is equal to the first preset pressure, the fibrous electrode after the second rolling can still maintain its fibrous shape.

[0039] This embodiment uses two low-pressure rolling processes (i.e., the rolling pressure of both processes is much lower than the rolling pressure applied by traditional steel rollers to the sheet electrode of lithium battery), which avoids the flexibility damage of the fibrous electrode caused by a single high-pressure rolling process, while ensuring the density of the fibrous electrode to meet the electrochemical performance requirements, thus balancing the flexibility and density of the fibrous electrode.

[0040] It should be noted that the purpose of the two low-pressure rolling processes is to further improve the uniformity of the density of the fibrous electrode. Therefore, the second preset pressure F2 of the second rolling is not limited to being equal to the first preset pressure F1. In another specific embodiment of this example, the second preset pressure F2 applied by the second set of rollers 2 to the fibrous electrode 3 is less than the first preset pressure F1 applied by the first set of rollers 1 to the fibrous electrode 3. In one specific embodiment, F2 is preferably 0.1-0.5 MPa, and F1 is preferably 0.5-1 MPa. This embodiment, by using a gradient pressure rolling method where the second preset pressure F2 is less than the first preset pressure F1, can further improve the uniformity of the density of the fibrous electrode and optimize the electrode structure stability of the fibrous electrode compared to a rolling method where the second preset pressure is equal to the first preset pressure.

[0041] Furthermore, to avoid uneven force distribution caused by repeated rolling in the same direction, in this embodiment, the rolling direction of the second pair of rollers 2 in two adjacent pairs of rollers is different from that of the first pair of rollers 1. For example... Figure 1 As shown, in a preferred embodiment, the rolling direction of the second set of rollers 2 is perpendicular to the rolling direction of the first set of rollers 1. By setting the rolling directions of the two rolling processes perpendicularly, the fibrous electrode can be subjected to force from multiple directions, thereby ensuring uniform force in each direction and maintaining the original shape of the fibrous electrode (in this embodiment, it is kept cylindrical).

[0042] In this embodiment, the rolling direction of the second set of rollers 2 is perpendicular to the rolling direction of the first set of rollers 1. The specific implementation method is as follows: Figure 8As shown, the direction of the first preset pressure F1 applied by the first set of rollers 1 to the fibrous electrode 3 is perpendicular to the direction of the second preset pressure F2 applied by the second set of rollers 2 to the fibrous electrode 3.

[0043] Specifically, such as Figure 1 and Figure 4 As shown, the two rolls of the first set of rollers 1 (hereinafter referred to as the first roll 11 and the second roll 12 for ease of description) apply a first preset pressure F1 to the fibrous electrode 3 from two directions (hereinafter referred to as the first direction and the second direction for ease of description). Figure 1 and Figure 7 As shown, the two rolls of the second set of rollers 2 (hereinafter referred to as the third roll 21 and the fourth roll 22 for ease of description) apply a second preset pressure F2 to the fibrous electrode 3 from two directions (hereinafter referred to as the third direction and the fourth direction for ease of description).

[0044] like Figure 4 As shown, the first roller 11 applies a first preset pressure F1 to the upper half-arc surface of the fibrous electrode 3 from a first direction, and the second roller 12 applies the first preset pressure F1 to the lower half-arc surface of the fibrous electrode 3 from a second direction. Figure 7 As shown, the third roll 21 applies a second preset pressure F2 to the left half-arc surface of the fibrous electrode 3 from a third direction, and the fourth roll 22 applies a second preset pressure F2 to the right half-arc surface of the fibrous electrode 3 from a fourth direction. In summary, the rolling directions of the two rolls are set perpendicularly, as shown... Figure 8 As shown, the fibrous electrode 3 can be subjected to force in all four directions from the first direction to the fourth direction, thereby ensuring that the force is uniform in each direction and thus maintaining the original shape of the fiber.

[0045] It should be noted that the direction of action of the first preset pressure F1 and the direction of action of the second preset pressure F2 are perpendicular to each other, which is only a preferred embodiment of this invention. In the actual rolling process, the rolling direction of the second rolling can be adjusted according to the effect of the first rolling, that is, the angle between the first preset pressure F1 and the second preset pressure F2 can be selected within the range of greater than 0° and less than 180°. The core is that by making the rolling directions of two adjacent sets of rollers different, it is ensured that the fibrous electrode is subjected to uniform force in all directions after multiple rolling, thereby maintaining the original shape of the fiber.

[0046] To further ensure uniform stress on the fibrous electrode during the two rolling processes and avoid changes in fiber morphology, the rolling speed of the second set of rollers performing the second rolling of the fibrous electrode in this embodiment is the same as the rolling speed of the first set of rollers performing the first rolling of the fibrous electrode. By setting the rolling speed to be the same for both rolling processes, the twisting and deformation of the electrode fibers caused by different rolling speeds can be avoided.

[0047] Furthermore, in order to prevent the fibrous electrode from sliding and deforming under rolling pressure during the rolling process, each pair of rollers in this embodiment has rolling grooves arranged around the two rollers. During rolling, the two rolling grooves surround each other to form a rolling cavity that matches the shape of the fibrous electrode. This allows the rolling cavity to apply rolling pressure to the fibrous electrode embedded inside during the rolling process, while ensuring that the fibrous electrode subjected to rolling pressure neither slides nor is excessively squeezed.

[0048] Specifically, such as Figure 1 As shown, the fibrous electrode 3 in this embodiment is a long cylindrical shape, and the rolling cavity that matches the shape of the fibrous electrode is also cylindrical. Figure 1 As shown, the first roll 11 and second roll 12 of the first set of rollers 1, and the third roll 21 and fourth roll 22 of the second set of rollers 2, all have circumferentially arranged roll grooves 10 on their surfaces. Figure 2 and Figure 3 As shown, the two roller pressing grooves 10 of the first roll 11 and the second roll 12, which are arranged opposite to each other, form the first roller pressing cavity 101 after being connected to each other. Figure 4 As shown, the inner contour of the first roller pressing cavity 101 matches the outer shape of the fibrous electrode 3, and both have circular cross-sections; Figure 5 and Figure 6 As shown, the two roller pressing grooves 10 of the third roll 21 and the fourth roll 22, which are arranged opposite to each other, form the second roller pressing cavity 201 after they are joined together. Figure 7 As shown, the inner contour of the second roller pressing cavity 201 matches the outer shape of the fibrous electrode 3, and both have circular cross-sections.

[0049] In specific implementation, the inner diameters of both the first roller pressing cavity 101 and the second roller pressing cavity 201 are configured to be slightly smaller than the initial outer diameter of the fibrous electrode. This ensures that the fibrous electrode can be precisely embedded into the first roller pressing cavity 101 and the second roller pressing cavity 201 and fit tightly against their inner walls during roller pressing. The purpose of this dimensional fit is twofold: firstly, to prevent relative sliding of the fibrous electrode through the limiting effect of the cavities, ensuring uniform force in all directions; and secondly, to avoid excessive compression that could damage the microfiber morphology of the fibrous electrode. Conversely, if the inner diameters of the first roller pressing cavity 101 and the second roller pressing cavity 201 are too large, the fibrous electrode is prone to displacement and sliding within the cavities, leading to uneven stress distribution; if the inner diameters are too small, excessive compression will occur, causing irreversible deformation and damage to the fibrous electrode.

[0050] In a preferred embodiment, when the initial outer diameter of the fibrous electrode is selected to be 0.1 to 1 mm, the inner diameter of the first roller pressing cavity 101 and the second roller pressing cavity 201 is 0.05 to 0.1 mm smaller than the initial outer diameter of the fibrous electrode.

[0051] It should be noted that, since different specifications of flexible battery electrodes are adapted to different fibrous electrode specifications, the shapes of the first rolling cavity 101 and the second rolling cavity 201 are not limited to cylindrical. In specific implementations, the shapes of the first rolling cavity 101 and the second rolling cavity 201 can be flexibly adjusted according to the shape of the fibrous electrode, so that the fibrous electrode can be precisely embedded in the first rolling cavity 101 and the second rolling cavity 201 during the rolling process, achieving a tight fit with the first rolling cavity 101 and the second rolling cavity 201.

[0052] This embodiment achieves uniform force application to the fibrous electrode in all circumferential directions by setting a first rolling chamber 101 and a second rolling chamber 201 that match the shape of the fibrous electrode. This structural design effectively overcomes the defects of existing planar rolling processes, avoids excessive local pressure on the fibrous electrode, and thus fundamentally prevents fiber breakage during the rolling process.

[0053] In order to further control the rolling pressure during the rolling process, each pair of rolls in this embodiment includes: a rolling layer that is in direct contact with the fibrous electrode; and a roll core that is enclosed inside the rolling layer. The rolling layer is made of a tough material, and the roll core is made of a lightweight material.

[0054] In this embodiment, the preferred toughening material is silicone, polyurethane, or nitrile rubber. Due to the excellent elasticity and cushioning properties of the toughening material, when used in conjunction with a low-pressure rolling process, the rolling layer made of the toughening material can effectively absorb some of the rolling pressure. This cushioning mechanism prevents the fibrous electrode from being over-compacted, thereby preserving the porous structure within the fibers of the fibrous electrode. This not only effectively maintains the deformation capability and flexibility of the fibrous electrode but also fundamentally avoids flexibility degradation or microstructural damage caused by over-compactment.

[0055] In this embodiment, the weight of the roller core made of lightweight material is configured to be 1 / 3 to 1 / 2 of the weight of a traditional steel roller. This lightweight design effectively reduces the self-weight load during the rolling process, preventing the fibrous electrodes from being over-compacted due to excessive roller core weight, thus protecting the flexibility of the fibrous electrodes from damage. On the other hand, it significantly reduces the rotational inertia of the roller core, making the start-up and shutdown response and parameter adjustment of the equipment faster and smoother, greatly improving the convenience of operation and production efficiency.

[0056] In one specific embodiment of this example, the lightweight material is a lightweight alloy. Preferably, the lightweight alloy is an aluminum alloy or a magnesium alloy.

[0057] In another specific embodiment of this invention, the roll-formed layer and the roll core are integrally formed. The lightweight material is preferably silicone, polyurethane, or nitrile rubber.

[0058] Furthermore, the rolling process for the flexible battery electrode in this embodiment also includes real-time temperature control of the rolled layer during the rolling process. By controlling the temperature of the rolled layer in real-time during the rolling process, it is possible to prevent the rolled layer from softening or deforming due to excessively high temperature, or from losing its elasticity and cushioning properties due to excessively low temperature. Controlling the temperature of the rolled layer within a suitable range can ensure a stable rolling effect on the fibrous electrode, protecting the electrode flexibility and fiber morphology of the fibrous electrode.

[0059] In one specific embodiment, the real-time temperature is preferably 25–40°C.

[0060] Furthermore, the rolling process method for the flexible battery electrode in this embodiment also includes: pre-treating the fibrous electrode before feeding it into the first set of rollers. Specifically, the pre-treating steps for the fibrous electrode include: cleaning the surface of the fibrous electrode to remove impurities and loose electrode fibers, straightening the arrangement of the electrode fibers to ensure that the electrode fibers are not tangled or knotted together.

[0061] Furthermore, the rolling process method for the flexible battery electrode in this embodiment also includes: after the second set of rollers performs a second rolling process on the fibrous electrode, the fibrous electrode is subjected to finished product inspection. Specifically, the specific steps for inspecting the fibrous electrode include: inspecting the flexibility, density, and fiber morphology of the fibrous electrode after the second rolling process, screening qualified products, and completing the rolling process.

[0062] Example 2

[0063] like Figure 9 As shown, the rolling device for the flexible battery electrode in this embodiment includes four sets of rollers arranged sequentially along the conveying direction of the fibrous electrode. The four sets of rollers are used to roll the fibrous electrode four times. The structure of each pair of rollers is the same as in Embodiment 1, and will not be described again here.

[0064] Accordingly, the rolling process of the flexible battery electrode in this embodiment includes: feeding the fibrous electrode sequentially between four sets of rollers for four rolling processes; wherein the rolling process of each pair of rollers is the same as in Embodiment 1, and will not be repeated here.

[0065] It should be noted that the purpose of repeatedly rolling the fibrous electrode is to effectively improve its density and optimize its microstructure while avoiding damage to the electrode's flexibility and ensuring the integrity of the fiber morphology, thereby enhancing the mechanical strength and electrochemical performance of the fibrous electrode. Therefore, the process of repeatedly rolling the fibrous electrode is not limited to Examples 1 and 2, as long as it achieves the purpose of this application.

[0066] Example 3

[0067] like Figure 10 As shown, in this embodiment, based on embodiment one, two circumferentially arranged roll pressing grooves are added to the surface of each roll of each pair of rolls. This allows for the simultaneous roll pressing process on three fibrous electrodes, improving roll pressing efficiency.

[0068] This invention achieves non-destructive rolling of fibrous electrodes through the following principle, the specific principle of which is as follows: 1. Shape Adaptation Principle: This application provides roll pressing grooves on the surface of each pair of rollers. During rolling, the two roll pressing grooves enclose a roll pressing cavity with a size slightly smaller than that of the fibrous electrode. The shape of this roll pressing cavity matches that of the fibrous electrode. During rolling, the fibrous electrode can be embedded in the roll pressing cavity, achieving full fit between the fibrous electrode and the roll pressing cavity of the pair of rollers. This avoids uneven force distribution caused by planar rollers and effectively prevents the fibrous electrode from sliding in the roll pressing cavity, thereby ensuring uniform force distribution and maintaining the original fiber morphology. At the same time, the roll pressing cavity adopts a structure that matches the shape of the fibrous electrode, which can disperse the rolling pressure and avoid excessive local pressure that could lead to fiber breakage. 2. Flexible buffering principle: The roller pressing layer on the surface of the rollers in this application is made of tough material, which has good buffering performance and can absorb part of the roller pressing pressure. Combined with the low-pressure roller pressing design that is much lower than that of conventional electrode sheets, it can effectively prevent the fibrous electrode from being over-compacted, thereby maximizing the preservation of its flexibility indicators such as bendability, and ensuring that the fibrous electrode meets the complex deformation requirements of irregular flexible batteries. 3. Multi-directional uniform force principle: This application uses at least two sets of rollers with perpendicular rolling directions to roll the fibrous electrode at least twice. By setting the rolling directions of the two sets of rollers perpendicular to each other, the fibrous electrode can be subjected to force from multiple directions, thereby ensuring uniform force in each direction and avoiding uneven fiber force and deformation caused by unidirectional rolling. This ensures uniform density of the fibrous electrode in each direction after rolling, while maintaining the original fiber morphology, thus solving the core problem of fibrous electrode deformation during rolling. 4. Gradient densification principle: The first rolling press uses the first preset pressure to achieve the initial densification of the electrode. The second rolling press uses a gradient low-pressure rolling method with the second preset pressure being lower than the first preset pressure to further improve the density. The gradient low-pressure design avoids electrode damage caused by a single high pressure and ensures that the electrode density meets the electrochemical performance requirements, taking into account both flexibility and density.

[0069] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A rolling device for flexible battery electrodes, characterized in that, The flexible battery electrode is a fibrous electrode with an initial outer diameter of 0.1–1 mm. The rolling device for the flexible battery electrode includes at least two sets of rollers arranged sequentially along the conveying direction of the fibrous electrode for repeatedly rolling the fibrous electrode; the at least two sets of rollers include a first set of rollers and a second set of rollers; wherein... The first set of rollers includes a first roll and a second roll, and a first rolling chamber is formed between the first roll and the second roll for applying a first preset pressure to the fibrous electrode fed therein to perform a first rolling. The second set of rollers includes a third roller and a fourth roller. A second rolling chamber is formed between the third roller and the fourth roller, which is used to apply a second preset pressure to the fibrous electrode after the first rolling to perform a second rolling. The direction of the second preset pressure is different from the direction of the first preset pressure, so that the fibrous electrode is uniformly stressed in the circumferential direction after multiple rolling.

2. The rolling device for flexible battery electrodes according to claim 1, characterized in that, The fibrous electrode is sequentially inserted through the first rolling chamber and the second rolling chamber; the inner contours of the first rolling chamber and the second rolling chamber are matched with the outer shape of the fibrous electrode to form a circumferential limit on the fibrous electrode.

3. The rolling device for the flexible battery electrode according to claim 1, characterized in that, The rolling speed of the second set of rollers during the second rolling is equal to the rolling speed of the first set of rollers during the first rolling.

4. The rolling device for flexible battery electrodes according to claim 2, characterized in that, The surfaces of the first roll, the second roll, the third roll, and the fourth roll are all provided with roll pressing grooves arranged circumferentially. In the roll pressing state, the two roll pressing grooves arranged opposite to each other on the first roll and the second roll are connected to each other to form the first roll pressing cavity, and the two roll pressing grooves arranged opposite to each other on the third roll and the fourth roll are connected to each other to form the second roll pressing cavity. The cross-sectional area of ​​the first roller pressing cavity is smaller than the initial cross-sectional area of ​​the fibrous electrode, so that the first roller pressing cavity forms an interference fit with the fibrous electrode during the rolling process, so as to apply the first preset pressure to the fibrous electrode; The cross-sectional area of ​​the second roller pressing cavity is smaller than the initial cross-sectional area of ​​the fibrous electrode, so that the second roller pressing cavity forms an interference fit with the fibrous electrode during the rolling process, so as to apply the second preset pressure to the fibrous electrode.

5. The rolling device for the flexible battery electrode according to claim 4, characterized in that, The fibrous electrode is in the shape of a long cylinder; the inner diameter of the first roller pressing cavity is smaller than the initial outer diameter of the fibrous electrode, so that the fibrous electrode and the first roller pressing cavity form an interference fit, so as to apply the first preset pressure to the fibrous electrode; the inner diameter of the second roller pressing cavity is smaller than the initial outer diameter of the fibrous electrode, so that the fibrous electrode and the second roller pressing cavity form an interference fit, so as to apply the second preset pressure to the fibrous electrode.

6. The rolling device for the flexible battery electrode according to claim 4, characterized in that, The first roll, the second roll, the third roll, and the fourth roll each include: a roll pressing layer that is in direct contact with the fibrous electrode, the roll pressing layer being made of a tough material; and a roll pressing groove disposed on the roll pressing layer.

7. The rolling device for flexible battery electrodes according to claim 6, characterized in that, The toughening material is silicone, polyurethane, or nitrile rubber.

8. The rolling device for the flexible battery electrode according to claim 6, characterized in that, The first roll, the second roll, the third roll, and the fourth roll also include a roll core, which is covered inside by the roll pressing layer and is made of a lightweight material.

9. The rolling device for the flexible battery electrode according to claim 1, characterized in that, The second preset pressure applied to the second set of rollers is equal to the first preset pressure applied to the first set of rollers.

10. The rolling device for the flexible battery electrode according to claim 1, characterized in that, The second preset pressure applied to the second set of rollers is less than the first preset pressure applied to the first set of rollers, so as to form a gradient roller pressure.

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