Negative plate rebound thickness consistency roller and roller passing system

Abstract

The utility model provides a negative plate rebound thickness consistency roller, which relates to the technical field of lithium battery preparation, and comprises a roller body, a first connecting part, a conductive mechanism, a second connecting part and an electric heating component, the roller body comprises an inner cavity, and the electric heating assembly is arranged in the inner cavity; a first through hole is formed in the second axial end of the roller; the first connecting part comprises a connecting shaft and a conductive mechanism, and the conductive mechanism is arranged on the connecting shaft in a sleeving manner; the connecting shaft is provided with a second through hole; the electric heating assembly is electrically connected with the conductive mechanism through the first through hole and the second through hole, and the conductive mechanism is further used for being connected with an external power source. The roller can fully and quickly release the stress in the negative plate, so that the negative plate can be quickly rebounded, the rebounding thickness consistency of the negative plate is relatively high, the production efficiency is improved, and the reject ratio in the lithium battery production process is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery preparation, and particularly relates to a roller and a passing roller system for consistent thickness of negative electrode sheet rebound. Background Art

[0002] Currently, the market has put forward higher requirements for the fast charging ability of batteries, and fast charging technology is also an important part of improving the performance of battery cells. The preparation of lithium-ion battery electrodes includes processes such as pulping, coating, rolling, and die-cutting. In the pulping process, the binder plays a crucial role in the performance of the battery. Therefore, studying fast-charging binders is of great significance for improving fast-charging performance. However, due to the molecular structure characteristics of fast-charging binders, the problem of electrode sheet rebound will inevitably occur. Therefore, certain measures need to be taken to solve the electrode sheet rebound problem caused by fast-charging binders.

[0003] Currently, the technical solutions for controlling electrode sheet rebound are: hot rolling process of electrode sheets, hot oil roller rolling process, and time shelving; the hot rolling process of electrode sheets is to heat the rollers of the rolling press to reduce the rebound of the electrode sheet by removing the moisture in the electrode sheet and reducing the rebound rate of the surface material of the electrode sheet after rolling. The hot oil roller rolling process releases the stress of the entire electrode sheet by rolling the cold-pressed electrode sheet through a hot oil roller, so as to achieve the rapid rebound of the electrode sheet after rolling. Time shelving is to let the electrode sheet stand for a long time to achieve complete rebound and then transfer it to the next process.

[0004] The hot rolling process of electrode sheets can reduce electrode sheet rebound, but the rollers are easily deformed by heat, thus affecting the consistency of electrode sheet thickness; the heating rate of the hot oil roller rolling process is slow, and the design of the oil inlet pipe and the oil outlet pipe is required. The equipment structure is complex and the later maintenance is more troublesome; relying on time shelving to achieve the rebound of the electrode sheet not only takes a long time and seriously affects production efficiency, but also the consistency of the rebound thickness of the electrode sheet is not high, increasing the defective rate in the production process of lithium batteries. Summary of the Utility Model

[0005] In view of this, the utility model aims to provide a roller and a passing roller system for consistent thickness of negative electrode sheet rebound to solve the problems of long electrode sheet rebound time and low consistency of negative electrode sheet rebound thickness in the prior art.

[0006] To solve the above technical problems, the present application is implemented as follows:

[0007] The present application provides a roller for consistent thickness of negative electrode sheet rebound, including: a roller body, a first connection part 10, a conductive mechanism 11, a second connection part 13, and an electric heating component 14;

[0008] The roller body includes an inner cavity, and the electric heating component 14 is arranged in the inner cavity; the first end of the roller 22 in the axial direction is fixedly connected to the second connecting portion 13; a first through hole is provided at the second end of the roller 22 in the axial direction;

[0009] The first connecting portion 10 includes a connecting shaft 12 and a conductive mechanism 11, and the conductive mechanism 11 is sleeved on the connecting shaft 12; the connecting shaft 12 has a second through hole, the connecting shaft 12 is fixedly connected to the second end, and the first through hole is communicated with the second through hole;

[0010] The electric heating component 14 is electrically connected to the conductive mechanism 11 through the first through hole and the second through hole, and the conductive mechanism 11 is also used for accessing an external power supply.

[0011] Optionally, the electric heating component 14 includes a plurality of electric heating tubes 15 arranged circumferentially around the first pipe 16, and the plurality of electric heating tubes 15 are arranged at intervals along the length direction of the first pipe 16, and the electric heating tubes 15 are fixedly connected to the first pipe 16.

[0012] Optionally, the first pipe 16 is provided with a plurality of wire passing holes in the circumferential direction and the length direction, the number and positions of the wire passing holes correspond to those of the electric heating tubes 15, and the heating wires of the electric heating tubes 15 are collected into the cavity of the first pipe 16 through the wire passing holes and pass through the first through hole to be electrically connected to the conductive mechanism 11.

[0013] Optionally, the conductive mechanism 11 is a conductive slip ring; the conductive slip ring includes a rotor and a stator, an incoming line interface is arranged on the axial side wall of the rotor close to the roller 22, a first wire is connected inside the incoming line interface, and the first wire is electrically connected to the heating wire of the electric heating tube 15; an outgoing line interface is arranged on the axial side wall of the stator far from the roller 22, a second wire is connected inside the outgoing line interface, and the second wire is connected to an external power supply.

[0014] Optionally, an insulating layer is provided on the outer surface of the shell of the roller 22.

[0015] Optionally, the electric heating tube 15 is of a Z-shaped structure.

[0016] Optionally, the heating temperature range of the electric heating tube 15 is 95°C to 100°C.

[0017] On the other hand, the present application provides a roller system for the consistency of the rebound thickness of a negative electrode sheet, which includes at least two rollers 22 for the consistency of the rebound thickness of the negative electrode sheet, an unwinding mechanism 17, a roller passing mechanism 18, a rolling mechanism 19, a rubber roller mechanism 20, a thickness gauge 21, and a winding mechanism 23; the thickness gauge 21 is provided at the front end of the roller 22, and the winding mechanism 23 is provided at the rear end of the roller 22; the rubber roller mechanism 20 is provided at the front end of the thickness gauge 21, and the roller passing mechanism 18 is arranged at both ends of the rolling mechanism 19.

[0018] Optionally, the arrangement of the rollers 22 includes two layers, upper and lower, and the upper rollers 22 and the lower rollers 22 are arranged alternately.

[0019] Optionally, the roller system for the consistency of the rebound thickness of the negative electrode sheet includes at least two sets of roller passing mechanisms 18, and the roller passing mechanism 18 includes a plurality of rollers, and the plurality of rollers are distributed in a vertically staggered manner.

[0020] Compared with the prior art, a roller for the consistency of the rebound thickness of a negative electrode sheet provided by the present utility model has the following advantages:

[0021] The roller is heated by an electric heating component, and the negative electrode sheet is in direct contact with the heated roller. The stress inside the negative electrode sheet can be fully and quickly released after heating, so that the thickness of the negative electrode sheet rebounds rapidly. In addition, the structure of the electric heating component is simple, it is convenient to install inside the roller, and only needs to be disassembled and replaced after a failure, and the later maintenance is more convenient. There is no need to rely on long-term static placement to achieve the rebound of the negative electrode sheet. The rebound negative electrode sheet can directly enter the next process for processing, the production efficiency is significantly improved, and the consistency of the rebound thickness of the negative electrode sheet is relatively high, thereby reducing the defective rate in the production process of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present utility model will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 is a schematic diagram of a roller for the consistency of the rebound thickness of a negative electrode sheet described in an embodiment of the present utility model;

[0024] Figure 2 is a cross-sectional schematic diagram of a roller for the consistency of the rebound thickness of a negative electrode sheet described in an embodiment of the present utility model;

[0025] Figure 3 is a schematic diagram of an electric heating tube of a roller for the consistency of the rebound thickness of a negative electrode sheet described in an embodiment of the present utility model;

[0026] Figure 4 is a schematic diagram of a roller passing system for the consistency of the rebound thickness of a negative electrode sheet described in an embodiment of the present utility model.

[0027] Description of reference numerals:

[0028] 10 - First connecting part; 11 - Conductive mechanism; 12 - Connecting shaft; 13 - Second connecting part; 14 - Electric heating assembly; 15 - Electric heating tube; 151 - Head end of the electric heating tube; 152 - Tail end of the electric heating tube; 16 - First pipeline; 17 - Unwinding mechanism; 18 - Roller passing mechanism; 19 - Rolling mill mechanism; 20 - Rubber roller mechanism; 21 - Thickness gauge; 22 - Roller; 23 - Rewinding mechanism. Detailed implementation manners

[0029] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and should not be construed as a limitation to the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0030] The terms "first" and "second" in the description and claims of the present invention may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after.

[0031] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0032] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] The present utility model will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0034] A first aspect of the present utility model provides an embodiment, referring to Figures 1 - 3 a roller for the consistency of the rebound thickness of a negative electrode sheet shown, the roller 22 includes a roller body, a first connection portion 10, a conductive mechanism 11, a second connection portion 13, and an electric heating component 14;

[0035] The roller body includes an inner cavity, and the electric heating component 14 is arranged in the inner cavity; a first end in the axial direction of the roller 22 is fixedly connected to the second connection portion 13; a first through hole is arranged at a second end in the axial direction of the roller 22;

[0036] The first connection portion 10 includes a connection shaft 12 and a conductive mechanism 11, and the conductive mechanism 11 is sleeved on the connection shaft 12; the connection shaft 12 has a second through hole, the connection shaft 12 is fixedly connected to the second end, and the first through hole is communicated with the second through hole;

[0037] The electric heating component 14 is electrically connected to the conductive mechanism 11 through the first through hole and the second through hole, and the conductive mechanism 11 is also used for accessing an external power supply.

[0038] The roller body can be cylindrical, and the inner cavity of the roller body can be a hollow structure. The overall weight of the hollow-structured roller is greatly reduced, which not only reduces the inertial moment when the roller 22 rotates, making the start, stop, and speed change of the roller 22 faster and smoother, but also reduces energy consumption and noise. The electric heating component 14 is installed inside the roller 22, and the space inside the hollow roller can enable the heat generated by the electric heating component 14 to be quickly and evenly transferred to the surface of the shell of the roller 22 and the negative electrode sheet in contact with the surface of the shell of the roller 22, thereby improving the heat treatment effect on the negative electrode sheet. In another embodiment, the inner cavity of the roller body can also be a solid structure, and the electric heating component 14 is embedded inside the roller 22. The solid-structured roller has a simple structure and is easy to manufacture, which can reduce the manufacturing and maintenance costs. Of course, the present application does not limit the inner cavity structure of the roller body.

[0039] A second connecting portion 13 is fixedly connected to the first end of the roller 22 in the axial direction. The second connecting portion 13 may include an end cap and a bearing. The end cap can seal the internal space of the roller 22 to prevent heat dissipation and the entry of external impurities, thereby protecting the working performance of the internal electric heating component 14; the bearing can provide stable support for the rotation of the roller 22 and reduce the friction and resistance during the rotation of the roller 22, enabling the roller 22 to operate smoothly and efficiently. A first through hole is provided at the second end of the roller 22 in the axial direction. Specifically, the first through hole is provided at the axial center position of the side wall at the second end of the roller body. The size of the first through hole is larger than the cross-sectional size of the first pipe 16, so that the first pipe 16 can pass through the first through hole.

[0040] The first connecting portion 10 includes a connecting shaft 12 and a conductive mechanism 11. The connecting shaft 12 is fixedly connected to the side wall at the second end of the roller 22 in the axial direction. The conductive mechanism 11 is fixedly connected to the connecting shaft 12 by bolts. The side of the connecting shaft 12 close to the roller 22 has a second through hole, which is communicated with the first through hole and has the same size as the first through hole. Specifically, a wiring hole is provided on the surface of the connecting shaft 12, so that the heating wire of the electric heating component 14 passes through the first through hole and the second through hole and is connected to the wire at one end of the conductive mechanism 11 through the wiring hole. In addition, after the connection between the heating wire and the wire of the conductive mechanism 11 is completed, the connection part is wrapped with insulating tape or other insulating materials to improve the insulation performance of the wire connection and prevent safety hazards such as short circuits or electric shocks. The wire at the other end of the conductive mechanism 11 is connected to an external power supply to provide power for the electric heating component 14. After being energized, the electric heating component 14 generates heat, increasing the temperature on the surface of the roller 22, thereby effectively releasing the internal stress of the negative electrode sheet in contact with the roller 22, and thus the negative electrode sheet rebounds quickly and fully.

[0041] Preferably, the roller 22 can also be equipped with a temperature control system (not shown in the figure) to accurately control the heating temperature of the roller 22. The temperature control system includes components such as a temperature sensor, a controller, and an actuator. The temperature control system can monitor the temperature change of the roller 22 in real time and automatically adjust the power output of the electric heating component 14 according to the set value to keep the temperature of the roller 22 within a predetermined range.

[0042] Optionally, the electric heating component 14 includes a plurality of electric heating tubes 15 arranged circumferentially around the first pipe 16, and the plurality of electric heating tubes 15 are arranged at intervals along the length direction of the first pipe 16. The electric heating tubes 15 are fixedly connected to the first pipe 16.

[0043] In this embodiment, the electric heating tube 15 mainly includes a metal shell, heating wire, insulation layer, lead rod, sealing structure, fastener, wiring part, and protective shell, etc. The metal shell is the outer structure of the electric heating tube 15, which can be made of stainless steel or carbon steel. Stainless steel and carbon steel have excellent properties such as high temperature resistance and corrosion resistance. The metal shell can not only provide firm support and protection for the heating wire but also ensure the heat conduction efficiency during the heating process. Parameters such as the wall thickness and diameter of the metal shell can be designed according to specific process requirements. The heating wire is the core component of the electric heating tube 15 and can be made of alloy materials with high resistivity and high melting point (such as nickel-chromium alloy, iron-chromium-aluminum alloy, etc.). When an electric current passes through the heating wire, electrical energy is converted into heat energy, thus achieving the heating effect. Parameters such as the material, diameter, and length of the heating wire directly affect the heating power, temperature uniformity, and service life of the electric heating tube 15. The insulation layer is located in the gap between the heating wire and the metal shell and mainly plays the role of electrical insulation, preventing the heating wire from coming into direct contact with the metal shell during operation, which may cause short circuit or leakage. The insulation layer can be made of materials with high temperature resistance and aging resistance, such as magnesium oxide powder, ceramics, etc., to ensure that the insulation layer can still maintain good insulation performance in a high-temperature environment. The lead rod is a key component connecting the heating wire to the external power supply and can be made of a high-temperature-resistant metal material the same as or similar to the metal shell. The lead rod passes through the sealing structure of the metal shell, leading out the electrical energy input end of the heating wire to the outside and connecting it to the external heating wire. In addition, the design of the lead rod needs to consider sealing performance, conductivity, and mechanical strength to ensure the overall performance and safety of the electric heating tube 15. The sealing structure is a key part in the electric heating tube to prevent the leakage of internal media (such as air, water, etc.) and the entry of external impurities. The sealing structure is located at the position where the lead rod passes through the metal shell and is made of special sealing materials and processes. The good performance of the sealing structure is crucial for maintaining the stability of the internal environment of the electric heating tube 15 and extending its service life. The fastener can tightly combine components such as the metal shell, heating wire, and insulation layer to ensure the stability and reliability of the electric heating tube 15 during operation. The wiring part is the interface where the electric heating tube 15 is connected to the external power supply, usually located at the end of the lead rod. The wiring part needs to have good conductivity and reliability to ensure that the electric current can be stably and safely transmitted to the heating wire. In addition, the electric heating tube 15 can also be equipped with a protective shell, which can be made of materials with high temperature resistance and corrosion resistance, and can further protect the electric heating tube 15 from the influence of the external environment, improving the durability and safety of the electric heating tube 15.

[0044] The electric heating tubes 15 are arranged at intervals in the circumferential direction and the longitudinal direction of the first pipe 16. The number of the electric heating tubes 15 arranged around the circumferential direction of the first pipe 16 can be 8, and the number of the electric heating tubes 15 along the longitudinal direction of the first pipe 16 can be determined according to the length of the roller 22, and the present application does not limit it. The uniform arrangement of the electric heating tubes 15 around the circumferential direction and the longitudinal direction of the first pipe 16 can not only make the heat received by each point on the surface of the shell of the roller 22 approximately equal, maintain a relatively stable temperature field during operation, and avoid local overheating or insufficient heating on the surface of the roller 22 during rotation, resulting in uneven stress release inside the negative electrode sheet in direct contact with its surface, and thus the situation of inconsistent rebound thickness of the negative electrode sheet; but also make the thermal stress generated during the heating process of the roller 22 better dispersed and balanced, reduce problems such as deformation and cracking of the roller 22 caused by excessive thermal stress, and thus extend the service life of the roller 22.

[0045] Optionally, a plurality of wire passing holes are formed in the first pipe 16 in the circumferential direction and the longitudinal direction. The number and positions of the wire passing holes correspond to those of the electric heating tubes 15. The heating wires of the electric heating tubes 15 are collected into the cavity of the first pipe 16 through the wire passing holes, and pass through the first through hole to be electrically connected to the conductive mechanism 11.

[0046] The first pipe 16 is located at the axial center position of the roller 22 and supports the weight of the entire roller body and the internal electric heating tubes 15. The first pipe 16 can be a stainless steel pipe with a cavity inside. The stainless steel material has excellent properties such as high temperature resistance, high tensile strength, and high hardness, which can help improve the stability and reliability of the roller 22 during operation. Of course, the embodiments of the present application do not limit it. A number of wire passing holes are formed in the circumferential direction and the longitudinal direction of the first pipe 16. The number of the wire passing holes corresponds to the number of the electric heating tubes 15. The heating wires of the electric heating tubes 15 can be collected into the cavity of the first pipe 16 through the wire passing holes, so that the heating wires extend out of the first through hole and the second through hole along the axial direction of the first pipe 16 in an orderly manner to be electrically connected to the conductive mechanism 11, and the first pipe 16 can play a role in protecting the heating wires.

[0047] Optionally, the conductive mechanism 11 is a conductive slip ring; the conductive slip ring includes a rotor and a stator. An inlet interface is arranged on the axial side wall of the rotor close to the roller 22, and a first wire is connected inside the inlet interface. The first wire is electrically connected to the heating wire of the electric heating tube 15; an outlet interface is arranged on the axial side wall of the stator far from the roller 22, and a second wire is connected inside the outlet interface. The second wire is connected to an external power supply.

[0048] The conductive slip ring can achieve stable current transmission during the rotation of the roller 22. The conductive slip ring mainly consists of components such as a ring body (i.e., the conductive ring) composed of multiple metal ring tracks, a conductive brush in contact with the ring body, a fixed seat for fixation, and a housing for protection. The conductive ring can be made of metal materials such as red copper and brass, and usually, a high-quality precious metal coating is electroplated on the surfaces of the conductive ring and the conductive brush to meet the performance requirements of good electrical conductivity, wear resistance, and corrosion resistance of the conductive slip ring. The conductive ring is usually installed on the central axis but is insulated from the central axis. The insulating materials between the metal ring tracks and between the metal ring tracks and the central axis are made of nylon, phenolic plastic, or other non-conductive materials. The conductive brush mainly consists of a brush handle, brush bristles, and a spring. The brush handle is installed on the fixed seat, the brush bristles are in contact with the conductive ring to transfer electrical energy, and the spring mainly enables the brush bristles to be in close contact with the slip ring. The conductive brush always remains in close contact with the slip ring during rotation to form a stable conduction path for current transmission. At the same time, to ensure the quality of conductive transmission, a certain pressure needs to be maintained between the conductive brush and the conductive ring to avoid contact failure or intermittent transmission phenomena. In addition, the number of conductive rings and conductive brushes can vary according to the needs of the equipment. The slip ring is generally contained within a metal housing to prevent components such as the conductive ring and the conductive brush from being affected by dust, moisture, and other factors that may cause malfunctions. The other ends of both the conductive ring and the conductive brush are connected to wires, and the number of metal rings and conductive brushes corresponds. For example, if the number of metal rings is designed to be 8 channels, the number of conductive brushes is also correspondingly designed to be 8 channels.

[0049] During the working process, the conductive slip ring generally has two working states: the first working state is that the conductive ring rotates and the conductive brush is stationary; the second working state is that the conductive brush rotates and the conductive ring is stationary. There is no essential difference between these two working states. Generally, the rotating part of the conductive slip ring during the working process is called the rotor, and the stationary part is called the stator. Specifically, the working principle of the conductive slip ring is based on the relative rotation of the rotor and the stator. The rotor part rotates with the roller 22, and the wire at one end of the rotor is electrically connected to the heating wire of the electric heating tube 15 inside the roller 22, while the stator part remains stationary, and the wire at one end of the stator is connected to an external power supply; when the roller 22 rotates, the current passes through the conductive brush, and the conductive brush relies on the force of the spring to contact the conductive ring and transmit the current to the heating wire of the electric heating tube, so that the electric heating tube is energized to generate heat.

[0050] In this embodiment, the conductive slip ring can be a through-hole conductive slip ring. There is a through-hole in the center of the through-hole conductive slip ring, and the connecting shaft 12 passes through the through-hole in the center of the through-hole conductive slip ring and is fixed to the through-hole conductive slip ring by bolts. The through-hole conductive slip ring rotates with the rotation of the roller 22. The rotor of the through-hole conductive slip ring can be located in the inner ring of the through-hole conductive slip ring, and the stator is located in the outer ring of the through-hole conductive slip ring. The first wire inside the rotor inlet interface is electrically connected to the heating wire of the electric heating tube 15, and the second wire inside the stator outlet interface is connected to an external power supply. Among them, several electric heating tubes 15 are usually required to be used in combination, and several electric heating tubes 15 can be connected by a parallel connection method: the electric heating tube 15 has two ports, a head end 151 and a tail end 152. The head ends 151 of each electric heating tube 15 are connected together through the heating wire, and are connected to the live wire of the power supply through the first wire and the second wire of the through-hole conductive slip ring. The tail ends 152 of each electric heating tube 15 are connected together and are connected to the neutral wire of the power supply through the first wire and the second wire of the through-hole conductive slip ring, so as to achieve stable power transmission during the rotation of the roller 22, and there will be no situation where the wire is kinked or disconnected, resulting in a short circuit or disconnection of the circuit.

[0051] Optionally, an insulating layer is provided on the outer surface of the housing of the roller 22.

[0052] The housing of the roller 22 is generally made of stainless steel material, and the outer surface of the circumference of the housing of the roller 22 needs to be subjected to an electroplating and polishing process to improve the flatness of the surface of the roller 22, so that the negative electrode sheet is smoothly and stably transmitted on the surface of the roller. An insulating layer will be provided on the outer surface of the housing of the roller 22. The insulating layer material needs to have excellent high temperature resistance, wear resistance and corrosion resistance, so that the insulating layer can maintain stable performance under long-term high temperature working conditions, and will not melt and burn, etc., and can resist corrosive substances in the working environment, preventing the insulation performance from decreasing or failing due to corrosion. Therefore, the insulating layer material can generally be a ceramic material, polytetrafluoroethylene (PTFE), etc. In addition, the thickness of the insulating layer can be determined according to the heating temperature of the roller 22. In this embodiment, the material and thickness of the insulating layer are not limited. On the one hand, the insulating layer can reduce the loss and waste of heat, make the temperature on the surface of the roller 22 more concentrated and stable, so that the roller 22 can transfer heat to the negative electrode sheet more efficiently during the heating process, improve the heating efficiency, and the stable temperature distribution can also improve the consistency of the rebound thickness of the negative electrode sheet; on the other hand, the insulating layer can prevent current from directly conducting through the surface of the housing of the roller 22 to the operator, reduce the risk of electric shock, and protect the life safety of the operator.

[0053] Optionally, the electric heating tube 15 is of a Z-shaped structure.

[0054] In this embodiment, the electric heating tube 15 is arranged in a Z-shaped structure. On the one hand, the Z-shaped structure can enable the electric heating tube 15 to form multiple bends and turns in a limited space, thereby increasing the heat exchange area between the electric heating tube 15 and the surrounding environment. This increased heat exchange area helps the heat to be transferred to the surface of the housing of the roller 22 faster and more evenly. On the other hand, the Z-shaped structure can create a complex air flow pattern around the electric heating tube 15, and this flow pattern can enhance the heat convection effect, thereby further improving the heating efficiency. Among them, the heat convection effect is one of the important ways of heat transfer.

[0055] Optionally, the heating temperature range of the electric heating tube 15 is 95°C to 100°C.

[0056] During the production process, stress will be generated inside the negative electrode sheet. There are mainly two reasons for the stress inside the negative electrode sheet: The first reason is that the negative electrode sheet usually contains auxiliary materials such as binders and conductive additives. These materials may generate stress during the mixing, coating, and drying processes. Especially when their thermal expansion coefficients do not match those of the negative electrode active material, the stress will be more obvious. The second reason is that defects such as pores, grain boundaries, and surface roughness may be introduced during the manufacturing process of the negative electrode sheet (such as the rolling process). These defects will become stress concentration points, exacerbating the generation and transmission of stress inside the negative electrode sheet. By heating, the stress inside the negative electrode sheet can be quickly released, thus achieving the rapid rebound of the negative electrode sheet. On the one hand, during the heating process, the temperature inside the negative electrode sheet gradually increases, resulting in an increase in the thermal motion of atoms and molecules inside the material, which in turn causes the thermal expansion of the material. Since there may be a temperature gradient inside the negative electrode sheet during the heating process, that is, the temperature increase rates of different parts are different, the expansion amounts will also be different. This non-uniform expansion will cause the originally compressed or stretched parts to be released to a certain extent after heating, thereby reducing or eliminating the stress inside the negative electrode sheet. On the other hand, in a high-temperature environment, the interaction forces between atoms or molecules inside the negative electrode sheet will change, causing some microstructures inside the material to be adjusted or rearranged. This adjustment or rearrangement helps to eliminate the residual stress generated during the processing. Therefore, at high temperatures, the stress inside the material will gradually relax, reducing the stress level. However, choosing the appropriate heating temperature is crucial for the battery negative electrode sheet. When the heating temperature is too high, it may have adverse effects on the negative electrode sheet, such as a decrease in material performance, a weakened bonding effect of the internal binder, and thermal stress concentration. Among them, the thermal stress concentration generated by high temperature may not be fully released during the subsequent cooling process, thus affecting the use performance of the negative electrode sheet. When the heating temperature is too low, the stress inside the negative electrode sheet may not be fully released, affecting the rapid rebound effect of the negative electrode sheet. In this embodiment, the heating temperature of the electric heating tube 15 is in the range of 95°C to 100°C. For example, the heating temperature can be 95°C, 96°C, 97°C, 98°C, 99°C, and 100°C, etc. When the heating temperature of the electric heating tube 15 is in the range of 95°C to 100°C, an ideal stress-relieving effect can be achieved on the negative electrode sheet.

[0057] On the other hand, the present utility model provides another embodiment. Referring to Figure 4A roller passing system for the consistency of the rebound thickness of a negative electrode sheet is shown. The roller passing system includes at least two rollers 22 for the consistency of the rebound thickness of the negative electrode sheet, an unwinding mechanism 17, a roller passing mechanism 18, a rolling mechanism 19, a rubber roller mechanism 20, a thickness gauge 21, and a winding mechanism 23. The thickness gauge 21 is provided at the front end of the roller 22, and the winding mechanism 23 is provided at the rear end of the roller 22. The rubber roller mechanism 20 is provided at the front end of the thickness gauge 21, and the roller passing mechanism 18 is arranged at both ends of the rolling mechanism 19.

[0058] The unwinding mechanism 17 is arranged at the starting position of the roller passing system. Its main function is to smoothly and continuously release the negative electrode sheet from the negative electrode sheet coil. During this process, the tension, speed, and position of the negative electrode sheet need to be precisely controlled to ensure the smooth progress of subsequent processing steps. The winding mechanism 23 is arranged at the end position of the roller passing system. Its main function is to tightly and orderly wind up the negative electrode sheet and fix it by means such as end adhesive tape to prevent the negative electrode sheet from spreading. During the winding process, the winding mechanism 23 needs to precisely control the tension and flatness of the negative electrode sheet to ensure the performance and quality of the negative electrode sheet in subsequent use. Between the unwinding mechanism 17 and the winding mechanism 23, there are successively arranged a roller passing mechanism 18, a rolling mechanism 19, a rubber roller mechanism 20, a thickness gauge 21, and several rollers 22. The roller passing mechanism 18 can precisely control the tension of the negative electrode sheet when transporting it, so that the negative electrode sheet remains stable during transportation and does not misalign or shift, providing a good basis for subsequent processing procedures. The rubber roller mechanism 20 includes a first roller and a second roller. The rubber roller mechanism 20 can compact the negative electrode sheet again. By applying a certain pressure, a tighter bond is formed between the coating of the negative electrode sheet and the current collector, improving the adhesion of the coating, thereby improving the performance of the negative electrode sheet. Among them, the surface of the first roller housing can be made of stainless steel material, and the surface of the second roller housing can be made of rubber material. The embodiments of the present application do not limit it. The thickness gauge 21 can monitor the thickness of the negative electrode sheet in real time during the rolling process to ensure that the thickness of the negative electrode sheet is controlled within the range required by the process. In addition, the thickness gauge 21 can be connected to the control system of the rolling mechanism 19 to adjust the roll gap and pressure parameters in real time to cope with thickness deviations and ensure the stability and consistency of the rolling process.

[0059] Refer to the attached Figure 4 , in this embodiment, the specific process of the roller passing system for the consistency of the rebound thickness of the negative electrode sheet is as follows:

[0060] S101: Place the coated and dried negative electrode sheet on the unwinding mechanism 17, adjust the negative electrode sheet to an appropriate position for fixation, and then pass the negative electrode sheet successively through the double-roller gap of the roller passing mechanism 18, the double-roller gap of the rolling mechanism 19, the double-roller gap of the rubber roller mechanism 20, the thickness gauge 21, and the roller 22, and finally connect the winding mechanism 23. During the whole process, it is necessary to ensure that the surface of the negative electrode sheet is flat and without wrinkles;

[0061] S102: adjusting the tension of the roller mechanism 18 to ensure that the negative electrode sheet can move forward smoothly during the rolling process without wrinkling or breaking;

[0062] S103: According to the process requirements, the gap distance between the upper and lower rollers in the roller mechanism 19 and the rubber roller mechanism 20 is adjusted to a preset height;

[0063] S104: Turn on the power, the motor (attached Figure 4 The roller mechanism 19 (not shown) drives the upper and lower rollers in the roller mechanism 19 to rotate simultaneously, and the winding mechanism 23 pulls the negative electrode sheet to stably pass through the gap between the roller mechanism 19 and the rubber roller mechanism 20. The negative electrode sheet is pressed to a preset thickness under the load of the roller in the roller mechanism 19; at the same time, the roller 22 heats the negative electrode sheet after rolling, quickly and fully releases the stress inside the negative electrode sheet, so that the negative electrode sheet can rebound quickly.

[0064] Optionally, the rollers 22 are arranged in two layers, the upper layer of rollers 22 and the lower layer of rollers 22 are arranged alternately.

[0065] The arrangement of the rollers 22 includes two layers, the upper rollers 22 and the lower rollers 22 are arranged alternately. The first aspect of this staggered arrangement is that it can improve the thermal utilization rate. When the rollers 22 are staggered up and down, the hot air can flow more smoothly from bottom to top. This flow pattern helps to evenly distribute and circulate the hot air, thereby improving the thermal utilization rate. The second aspect is that the staggered arrangement of the rollers 22 can not only make the negative electrode sheet contact with more roller surfaces during the transmission process, increase the heating area and heating time, but also can perform double-sided heating on the negative electrode sheet, fully release the stress inside the negative electrode sheet, and enable the negative electrode sheet to rebound quickly and fully. The third aspect is that the staggered layout can more effectively utilize the vertical space, thereby reducing the footprint of the entire roller system.

[0066] Optionally, the negative electrode sheet rebound thickness consistency roller system includes at least two groups of roller mechanisms 18, and the roller mechanisms 18 include a plurality of rollers, and the plurality of rollers are staggered and distributed up and down.

[0067] The roller system is provided with at least two groups of roller mechanisms 18, which can more accurately control the tension of the negative electrode sheet during the entire transmission process from the unwinding mechanism 17 to the rubber roller mechanism 20, and effectively prevent the negative electrode sheet from wrinkling, breaking or deflecting during the transmission process. In addition, in this embodiment, the rollers in the roller mechanism 18 can be set to three rollers, which is not limited by the embodiment of the present application. And these three rollers are arranged in an up-and-down staggered manner, which can enable the negative electrode sheet to be accurately and smoothly transmitted along a predetermined path, thereby improving the transmission effect of the negative electrode sheet.

[0068] In the embodiments of the present application, the roller is heated by an electric heating component, and the negative electrode sheet is in direct contact with the heated roller. The stress inside the negative electrode sheet can be fully and quickly released after heating, so that the thickness of the negative electrode sheet rebounds rapidly. In addition, the electric heating component has a simple structure, is convenient to install inside the roller, and only needs to be disassembled and replaced after a failure, making later maintenance more convenient. There is no need to rely on long-term static placement to achieve the rebound of the negative electrode sheet. The rebounded negative electrode sheet can directly enter the next process for processing, significantly improving the production efficiency, and the consistency of the rebound thickness of the negative electrode sheet is relatively high, thereby reducing the defective rate in the production process of lithium batteries.

[0069] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the purpose of the present invention and the scope protected by the claims, and all belong to the protection scope of the present invention.

Claims

1. A roller for the consistency of the rebound thickness of a negative electrode sheet, characterized in that, Comprising: A roller body, a first connecting portion (10), a conductive mechanism (11), a second connecting portion (13), and an electric heating assembly (14); The roller body includes an inner cavity, and the electric heating assembly (14) is disposed in the inner cavity; a first end in the axial direction of the roller (22) is fixedly connected to the second connecting portion (13); a first through hole is provided at a second end in the axial direction of the roller (22); The first connecting portion (10) includes a connecting shaft (12) and a conductive mechanism (11), and the conductive mechanism (11) is sleeved on the connecting shaft (12); the connecting shaft (12) has a second through hole, the connecting shaft (12) is fixedly connected to the second end, and the first through hole is communicated with the second through hole; The electric heating assembly (14) is electrically connected to the conductive mechanism (11) through the first through hole and the second through hole, and the conductive mechanism (11) is further used for accessing an external power supply.

2. The roller for the consistency of the rebound thickness of the negative electrode sheet according to claim 1, wherein The electric heating assembly (14) includes a plurality of electric heating tubes (15) arranged circumferentially around a first pipe (16), and the plurality of electric heating tubes (15) are spaced apart along the length direction of the first pipe (16), and the electric heating tubes (15) are fixedly connected to the first pipe (16).

3. The roller for the consistency of the rebound thickness of the negative electrode sheet according to claim 2, characterized in that, The first pipe (16) is provided with a plurality of wire passing holes in the circumferential direction and the length direction, the number and positions of the wire passing holes correspond to those of the electric heating tubes (15), and the heating wires of the electric heating tubes (15) are collected into the cavity of the first pipe (16) through the wire passing holes and pass through the first through hole to be electrically connected to the conductive mechanism (11).

4. The roller for the consistency of the rebound thickness of the negative electrode sheet according to claim 3, wherein The conductive mechanism (11) is a conductive slip ring; the conductive slip ring includes a rotor and a stator, an incoming line interface is provided on an axial side wall of the rotor close to the roller (22), a first wire is connected inside the incoming line interface, and the first wire is electrically connected to the heating wire of the electric heating tube (15); an outgoing line interface is provided on an axial side wall of the stator away from the roller (22), a second wire is connected inside the outgoing line interface, and the second wire is connected to an external power supply.

5. The roller for the consistency of the rebound thickness of the negative electrode sheet according to claim 1, wherein An insulating layer is provided on an outer surface of the shell of the roller (22).

6. The roller for the consistency of the rebound thickness of the negative electrode sheet according to claim 3, wherein The electric heating tube (15) is of a Z-shaped structure.

7. The roller for the consistent rebound thickness of the negative electrode sheet according to claim 2, wherein, The heating temperature range of the electric heating tube (15) is 95°C to 100°C.

8. A roll-over system for the consistent rebound thickness of a negative electrode sheet, characterized in that, Including at least two roller cylinders (22) for the consistency of the rebound thickness of the negative electrode sheet as described in any one of claims 1-7, an unwinding mechanism (17), a passing roller mechanism (18), a rolling roller mechanism (19), a rubber roller mechanism (20), a thickness gauge (21), and a winding mechanism (23); the thickness gauge (21) is provided at a front end of the roller cylinder (22), and the winding mechanism (23) is provided at a rear end of the roller cylinder (22); the rubber roller mechanism (20) is provided at a front end of the thickness gauge (21), and the passing roller mechanism (18) is arranged at both ends of the rolling roller mechanism (19).

9. The over-roller system for the consistent rebound thickness of the negative electrode sheet according to claim 8, wherein The arrangement of the roller cylinders (22) includes two layers, and the upper layer of the roller cylinders (22) and the lower layer of the roller cylinders (22) are arranged alternately.

10. The over-roller system for the consistent rebound thickness of the negative electrode sheet according to claim 8, wherein, Including at least two sets of over-roller mechanisms (18), the over-roller mechanisms (18) include a plurality of over-rollers, and the plurality of over-rollers are distributed vertically and staggeredly.

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