WO2024055263A1 - Copper plate roll welding roundness control device, copper cylinder manufacturing method, and cathode drum manufacturing method - Google Patents

Abstract

The present invention relates to the technical field of cathode drums, and relates to a copper plate roll welding roundness control device, a copper cylinder manufacturing method, and a cathode drum manufacturing method. The device comprises a shaft, a rounding support device, a hoop device, and a copper cylinder made by copper plate roll welding; the copper cylinder is a copper cylinder formed by copper plate roll welding; the rounding support device is coaxially arranged in the copper cylinder, and the hoop device is coaxially fixed to the periphery of the copper cylinder. The device mitigates the problems that when a copper-steel composite plate conventionally undergoes roll welding to form a copper-steel cylinder, the forming roundness is poor, and after an outer copper cylinder of the roll-welded copper-steel cylinder is subjected to finish turning, the residual thickness difference of a copper cylinder copper layer after finish turning is large, the thickness difference reaches 2-3 mm, and thus the uniformity of the conductive copper layer of a copper-steel composite cathode drum core cannot be guaranteed, which greatly affects the conductivity of the high-precision copper-steel composite drum core. The device realizes welding roundness control on copper cylinders, reduces the labor intensity of sheet metal rolling, reduces the assembly alignment after welding, improves the labor efficiency, and greatly reduces the labor intensity of operators.

Description

Copper plate coil welding roundness control device, copper cylinder preparation method and cathode roller preparation method Technical field

The invention belongs to the technical field of cathode rollers, and specifically relates to a copper plate welding roundness control device, a copper cylinder preparation method and a cathode roller preparation method.

Background technique

With the rapid development of global new energy vehicles, 5G communications, big data centers, artificial intelligence, etc., the demand for electrolytic copper foil is growing rapidly. Moreover, due to the increasingly higher performance requirements of copper foil required for power lithium batteries and energy storage lithium batteries, the thickness of copper foil is developing in a thinner direction, which places higher requirements on the cathode rollers for the production of electrolytic copper foil.

Since the production of electrolytic copper foil is carried out by roller continuous electrolysis method. The principle is to soak the cathode roller in the copper sulfate electrolytic solution and then apply a low voltage and high current DC power supply to cause the copper ions in the electrolytic solution to deposit on the titanium surface of the cathode roller to form a copper foil, and then use the rotation of the cathode roller to form a copper foil. The copper foil is peeled off and rolled up from the surface of the cathode roller, and then the surface of the copper foil is further treated to form a copper foil product. Therefore, the cathode roller for high-precision lithium battery foil is a core and key component that directly affects the output and quality of copper foil.

Since the cathode roller plays a decisive role in the production of copper foil, the requirements for it are also quite high: First, to increase the output of copper foil, the larger the diameter of the roller surface, the better. The diameter of the existing cathode roller for high-precision lithium foil has already been achieve

Secondly, the electrical conductivity is required to be quite good, and there should be no local hot spots due to poor local conductivity; and the roundness, straightness and surface roughness of the surface are required to be quite high; the surface is required to be able to withstand corrosion from electrolytic solutions for a long time, and the overall balance is And the overall weight is required to be as light as possible. At present, the structure of the cathode roller for high-precision lithium battery foil adopts a three-layer composite structure of titanium, copper and steel; that is, the outer ring is wrapped with titanium, the middle layer is made of copper for conductivity, and the inner layer is made of steel as the skeleton. At present, in the copper-steel structure of the cathode roller, copper and steel are combined into a copper-steel composite plate by explosion welding, and then rolled into a cylinder. The side plates and mandrels are installed and then rounded, and then a titanium cylinder is put on to form the cathode roller. In terms of manufacturing process, due to the large diameter when the copper-steel composite plate is rolled into a cylinder, the out-of-roundness tolerance can only be ≥4mm. In this way, the thickness of the copper cannot be guaranteed to be uniform during the rounding process, and cannot reach requirements, resulting in local poor conductivity and local hot spots; on the other hand, due to the special forming process of copper-steel composite panels, the price of copper-steel composite panels is particularly high. In this way, there are quite a few uncertain factors in the design and manufacturing, which makes it difficult to ensure the manufacturing quality of the cathode roller, thus seriously affecting the quality and output of the copper foil produced.

Contents of the invention

Technical issues to be resolved:

In order to avoid the shortcomings of the prior art, the present invention proposes a copper plate rolling and welding roundness control device, a copper cylinder preparation method and a cathode roller preparation method. A copper plate rolling and welding roundness control device is used to prepare high-precision uniform conductivity Copper cylinder, and using this copper cylinder to prepare lithium battery foil cathode roller, can well control the roundness of copper plate coiling and welding.

The technical solution of the present invention: a copper plate coiling and welding roundness control device, which is characterized in that: it includes a shaft, a rounding device, a hooping device, and a copper cylinder for coiling and welding of copper plates; the copper cylinder is a copper cylinder formed by coiling and welding of copper plates. cylinder;

The rounding assembly includes a steel end plate and a rounding plate. The steel end plate is a circular flat plate structure, and the rounding plate is a flat plate with an arc-shaped outer edge on one side; several rounding plates are evenly distributed in the circumferential direction through fastening pins. At the outer edge of the end face of the steel end plate, and the outer arcs of several rounding plates are located on the same circle, and the diameter of the circle is equal to the inner diameter of the copper cylinder; multiple rounding components are welded to the shaft along the axial direction to form a rounding The device is coaxially installed in the copper cylinder and used to ensure the roundness of the inner surface of the copper cylinder;

The hoop device is a hollow cylindrical structure composed of annular ribs and straight ribs. The multiple annular ribs are coaxial and evenly distributed along the axial direction. The multiple straight ribs are along the outer peripheral surfaces of the multiple rings. Uniformly distributed; the cylindrical structure is divided into two semi-cylindrical structures, the connection between the two semi-cylindrical structures is fastened by screws, and a gap is opened at the connection as a welding window; the hoop device is the same as The shaft is sleeved on the outer surface of the copper cylinder to ensure the roundness of the outer surface of the copper cylinder and prevent welding deformation.

A further technical solution of the present invention is that a plurality of relief holes are opened along the circumferential direction on the end surface of the steel end plate.

A further technical solution of the present invention is that three of the rounding components are welded to the shaft at equal intervals.

A further technical solution of the present invention is: the circular support plates have a fan-shaped structure, and 12 circular support plates are evenly distributed along the axial direction on each steel end plate; the coaxiality between the circumference and the axis of the outer arc surface of the circular support plates is ≤0.05mm.

A further technical solution of the present invention is that the gap between the inner circumferential surface of the hoop device and the outer surface of the copper cylinder is ≤0.1mm.

A method for preparing copper cylinders using a copper plate welding roundness control device, which is characterized by the following specific steps:

Step 1: Calculate the length L of the copper plate before rolling based on the size of the copper cylinder to be processed. The formula is as follows:

L＝πd-2.8t

Among them, d is the middle diameter of the copper plate roll, t is the thickness of the plate;

Step 2: Bending and rolling the copper plate through three rollers on the plate rolling machine, and then processing the welding groove at the longitudinal weld of the copper plate;

Step 3: Install the rounding device coaxially in the rounded copper plate, and the hooping device is coaxially clamped on the outer circumferential surface of the rounded copper plate. The radial gap between the rounded copper plate and the hooping device is ≤0.1mm; through the The rounding device and the hooping device realize the radial and axial position limiting of the rolled round copper plate, and at the same time ensure that the longitudinal weld seam is located at the welding window of the hooping device;

Step 3: Before welding, remove oil, rust and impurities from the welding groove and both sides of the surface to ensure the welding surface is clean;

Step 4: First, locally preheat the longitudinal weld of the rolled copper plate to above 200±10°C, and then perform welding to obtain a copper cylinder. After welding, implement thermal insulation and slow cooling; after welding, disassemble the rounding device;

Step 5: Heat and stress-relieve the longitudinal welds at the welding point of the copper cylinder. Use the flames of three air guns to bake along the circumferential and axial directions of the copper cylinder. Heat to 200°C and bake for 20 minutes to reduce the stress generated during welding of the copper cylinder. stress.

A further technical solution of the present invention is: in the second step, the weld seam adopts double-sided V-shaped grooves on both inner and outer sides and double-sided X-shaped grooves with blunt edges to ensure the consistency of the groove size, and the blunt edge is 1 mm. .

A further technical solution of the present invention is: in step four, argon arc welding (MIG) is used to weld and meet the flaw detection requirements.

A further technical solution of the present invention is: in step five, the alternative method of stress relief is to use a crawler heater to heat the longitudinal welds and tooling of the copper cylinder coil welding, and the heating temperature is controlled at 200°C ± 10°C. Keep warm time 20min.

A method for preparing a cathode roller for lithium battery foil, characterized in that: the cathode roller includes a titanium layer, a copper layer, and a steel layer in order from the outside to the inside; the titanium layer, the copper layer, and the steel layer are all cylindrical structures, The copper layer located in the middle layer is a high-precision rolled and welded copper cylinder, and the roundness of the copper cylinder is ≤0.5mm;

The specific steps of the preparation method are as follows:

Step 1: Carry out finishing machining on the inner hole of the welded copper cylinder to meet the assembly requirements of the cathode roller;

Step 2: Put the hooping device and the finished copper cylinder into a hot charging furnace or use a baking gun to heat the copper cylinder and hooping device as a whole. The copper cylinder and tooling will expand due to heat. After meeting the hot charging requirements, the cathode roller The steel cylinder roller core is installed inside the copper cylinder to meet the requirements of high-precision copper-steel composite cathode roller;

Step 3: After the copper cylinder is hot-loaded into the steel cylinder core of the cathode roller, the hoop device is disassembled, and the copper cylinder and the copper blocking plate are welded to the cathode roller core that realizes the copper-steel composite to meet the conductive requirements;

Step 4: After completing the welding in step 3, perform fine turning on the outer circle of the copper cylinder of the copper-steel composite cathode roller core. The outer circle of the copper cylinder should be finely turned ≤0.5mm on one side to ensure the conductivity of the copper-steel composite cathode roller core. The thickness uniformity of the copper layer and the accuracy of the copper-steel composite of the copper-steel composite roller core;

Step 5: Coaxially set the titanium cylinder on the outer peripheral surface of the copper-steel composite cathode roller core copper cylinder to complete the processing of the cathode roller for lithium battery foil.

beneficial effects

The beneficial effects of the present invention are: the present invention provides a copper plate coiling and welding roundness control device, a copper cylinder preparation method and a cathode roller preparation method. The device improves the forming roundness when the traditional copper steel composite plate is coiled and welded into a copper steel cylinder. Poor, it is impossible to ensure that the outer cylindrical copper cylinder will be finely turned after the copper steel cylinder is coiled and welded. The remaining thickness of the copper layer of the copper cylinder after finishing has a large difference, with a thickness difference of 2-3mm. It cannot guarantee that the copper-steel composite cathode roller core is conductive. The uniformity of the copper layer has a great influence on the conductivity of the high-precision copper-steel composite roller core; through this device, the welding roundness control of the copper cylinder is realized, reducing the labor intensity of sheet metal rolling and reducing assembly after welding. Alignment improves labor efficiency and greatly reduces the labor intensity of operators.

The specific advantages are: 1. The steel cylinder can achieve very good roundness and straightness after turning, which can ensure the smooth assembly of the copper cylinder. The copper cylinder is hot-fitted on the outer circle of the steel cylinder, and the outer circle is precision turned to ensure that the copper cylinder is The thickness of the conductive layer is very uniform; 2. The manufacturing process greatly reduces the production cost and material cost and improves the production efficiency; 3. The copper cylinder made of copper plate coil welding can ensure a good repair rate of the cathode roller.

The rounding device consists of a shaft, steel end plate, rounding plate, fastening pin, etc. The shaft is made of well-welded 20 steel. Since 20 steel has good strength and good weldability, the steel end plate is made of Q235B steel plate. 4-6 circular lightening holes are processed on the steel end plate to reduce the diameter of the holes.

On the one hand, reducing the hole can reduce the weight of the steel end plate, and on the other hand, it facilitates the welding of the longitudinal weld of the internal copper plate after the copper plate is rolled. After the shaft and steel end plate are welded, heat treatment is performed to relieve stress to reduce the stress generated during the welding process of the shaft and steel end plate. After annealing and stress relief, reaming pin holes are drilled on the outer circumference of the steel end plate, with 12-16 holes evenly distributed around the circumference. , used for the installation and assembly of 12-16 circular support plates evenly distributed around the circumference. The circular support plates are positioned and installed on the steel end plate through precisely assembled pin holes. After the circular support plates are assembled on the steel end plate, align the shaft and The rounding plate is processed to ensure that the coaxiality between the shaft and the outer circle of the rounding plate is controlled at ≤0.10mm, the roundness of the outer circle of the rounding plate is controlled at ≤0.05mm, and the circular runout of the outer circle of the rounding plate is controlled at ≤0.05 mm; the round support plate is made of 45 steel. After quenching and tempering treatment, the round support plate has good strength and hardness, which improves the wear resistance and strength of the round support plate. It can be used repeatedly and has good geometric accuracy.

The hoop hoop tooling is composed of two semicircular structures assembled into a full circle structure. The hoop hoop device tightly fits the copper cylinder to the hoop. After hooping, it passes through the axial fixing plate at the joint and tightens it with screws. . Each semicircular hoop device is made of steel plates that are rolled into shape by a plate rolling machine and then welded. Straight ribs parallel to the center line of the semicircle and circumferential ribs are welded to ensure the strength of the semicircular hoop device. And the stability of shape accuracy, stress relief annealing is performed after welding to reduce the stress generated during the welding process. The last two semi-circular hoop tooling are connected by bolts through the connecting plates at both ends, and the semi-circular hoop tooling is notched along the circumferential end. are connected together, and the window formed by this gap ensures the welding of the longitudinal weld of the copper cylinder when the copper plate is rolled into a copper plate. After the two semi-circular hoop toolings are fastened and assembled reliably, the hooping tooling is processed and welded on the vertical lathe to ensure the cylindricity accuracy of the inner hole of the hooping tooling and the outer hooping of the two copper cylinders assembled in one body. The roundness of the tooling is controlled at ≤0.05mm, and the circular runout is controlled at ≤0.05mm.

By limiting the position of the copper cylinder in the radial and axial directions through the rounding device and the hooping device, the stable welding of the copper cylinder can be ensured, and the deformation of the copper cylinder during welding can be reduced while ensuring the geometric stability of the copper cylinder. . After the copper cylinder is welded, the copper cylinder is heated with a grill or crawler heater to remove stress, thereby reducing the stress during welding of the copper cylinder and improving the dimensional stability of the copper cylinder after welding. The copper cylinder controlled by this tooling coil welding can achieve a copper cylinder roundness control of ≤0.5mm. At this time, the copper cylinder can be assembled with the precision-machined steel cylinder roller core through a large interference amount to achieve the copper cylinder and steel cylinder. The interference assembly of the roller core realizes the effective fit between the copper cylinder and the steel cylinder roller core, ensuring the conductivity uniformity of the copper-steel composite roller core of the cathode roller.

According to the copper plate formed by the copper plate rolling, according to the elongation of the copper plate rolling, the circumferential length of the copper plate is accurately calculated and processed. Through the rounding device and the hoop device, the copper cylinder and the rounding device and the outer hoop of the copper plate are ensured. The round device fits tightly, and the radial gap is less than 0.05mm. Note that the longitudinal weld of the copper cylinder along the axial direction is located at the welding window of the outer circle hoop device. After the copper cylinder is tightly assembled between the round device and the hoop device, Weld the longitudinal weld of the copper cylinder at the window of the outer hoop device. Pay attention to the welding grooves of the inner hole and the outer circle during welding. The inner hole and outer circle are staggered welded. The welding current is controlled at axial welding speed. The control is to use thermal insulation cotton for insulation after welding to prevent cracks after copper welding. The insulation time is 30-60 minutes. After cooling to normal temperature, remove the insulation layer. The copper cylinder welded by this method can achieve roundness control of ≤0.3mm, ensuring the geometric accuracy of the copper cylinder. Figure 6 is a schematic diagram of longitudinal welding seam welding of a copper cylinder using a hoop device window to roll a copper plate.

Description of drawings

Figure 1 is a schematic diagram of the titanium copper steel structure of the high-precision lithium foil cathode roller;

Figure 2 shows the special tooling diagram for copper plate coil welding;

Figure 3 is a partial view of the special tooling for copper plate coil welding.

Figure 4 is a perspective view of special tooling for copper plate coil welding.

Figure 5 is a diagram of a supporting circular plate.

Figure 6 is a schematic diagram of the assembly of the rounding device, the hooping device and the copper cylinder.

Figure 7 is a schematic diagram of the welding groove at the longitudinal weld of the copper plate.

Explanation of reference signs: 1-titanium cylinder, 2-copper cylinder, 3-steel cylinder, 4-shaft, 5-steel end plate, 6-circle support plate, 7-hooping device, 8-fastening pin, 9- Copper plate rolled and welded into a copper cylinder.

Detailed ways

The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " The directions indicated by "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" etc. or The positional relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, Therefore, it should not be construed as a limitation of the present invention.

Referring to Figure 1, a cathode roller for lithium battery foil of the present invention includes a titanium layer, a copper layer, and a steel layer in order from the outside to the inside; the titanium layer, copper layer, and steel layer are all cylindrical structures, located in the middle layer The copper layer is a high-precision coil-welded copper cylinder, the roundness of the copper cylinder is ≤0.5mm; the copper cylinder is coaxially thermally installed on the outer surface of the steel cylinder; the titanium cylinder is coaxially mounted on the copper cylinder Peripheral surface.

As shown in Figures 2 to 6, a roundness control device for a copper cylinder made by coiling and welding copper plates includes a shaft 4, a steel end plate 5, a rounding plate 6, a hoop device 7, a fastening pin 8, and a copper plate coil. Made of copper cylinder 9. Shaft 4 is a whole shaft, used to connect three steel end plates. The three steel end plates are welded to the shaft through continuous welds. When welding the steel end plates, ensure that the perpendicularity to the shaft is ≤0.3mm; the steel end plates There are 6-8 circular relief holes on the end face of 5 along the circumferential direction. During welding, the axial circumference of the 6-8 circular relief holes are consistent, which facilitates the subsequent manual welding of the copper cylinder rolled from the copper plate along the axial longitudinal seam. . After the steel end plate and the shaft are welded, stress relief annealing heat treatment must be performed to remove most of the stress generated during the welding process to ensure the stability of the rounding tooling.

There are 12-18 supporting circular plates evenly distributed along the circumferential direction on the outer edge of the end face of each steel end plate (the number of supporting circular plates can be increased or decreased appropriately according to the diameter of the coiled copper cylinder), which is fixed to a steel plate by 24-36 pins. On the end plate, there are 3 groups of steel end plates along the axial direction, with a total of 36-54 round support plates and a total of 72-108 pins. The round support plates are fixed to the steel end plates by pins, ensuring that the support round plates and the steel ends are securely connected. Precise positioning of the plate; after the rounding plate is fixed on the steel end plate, the rounding plate passes through the two round holes drilled and reamed on the steel end plate, and is fixed and assembled with the steel end plate through pins, ensuring that the rounding plate is There is no slippage with the steel end plate in the radial and circumferential directions. The outer circles of the support circular plates on the three steel end plates are precision turned to ensure the coaxiality of the outer diameter of the support circular plates with the shaft and the consistency of the outer diameters of the support circular plates on the three steel end plates. , while ensuring that the coaxiality of the outer circle of the supporting circular plates on the three steel end plates and the shaft is ≤0.05mm.

Referring to Figures 3 and 4, the hoop device 7 is two semicircular structures assembled into a full circle structure. The hoop device 7 is used to tightly fit the copper cylinder into the hoop. After the hoop is rounded, it is fixed axially at the joint. plate, tightened by screws. Each semi-circular hoop device is made of Q235B steel plate rolled by a plate rolling machine and then welded. The parallel ribs along the semi-circular center line and the circumferential ribs are welded to ensure the strength of the semi-circular hoop device. And the stability of shape accuracy, stress relief annealing is performed after welding to reduce the stress generated during the welding process. The last two semi-circular hoop tooling are connected by bolts through the connecting plates at both ends, and the semi-circular hoop tooling is notched along the circumferential end. are connected together, and the window formed by this gap ensures the welding of the longitudinal weld of the copper cylinder when the copper plate is rolled into a copper plate. After the two semi-circular hoop toolings are fastened and assembled reliably, the hooping tooling is processed and welded on the vertical lathe to ensure the cylindricity accuracy of the inner hole of the hooping tooling and the outer hooping of the two copper cylinders assembled in one body. The roundness of the tooling is controlled at ≤0.05mm, and the circular runout is controlled at ≤0.05mm.

The preparation method of a cathode roller for lithium battery foil of the present invention is specifically as follows:

First, calculate the rounding length of the copper plate: In order to ensure the accuracy of the rounding, the length of the copper plate before rounding needs to be accurately calculated. The three rollers of the copper plate are bent and rolled on the plate rolling machine. The circumferential length is calculated according to the roll. The pitch diameter d of the circle is calculated, and the exact length is calculated according to L=πd-2.8t, where t is the thickness of the plate. After ensuring the length of the copper plate, process the groove at the rounded longitudinal weld of the copper plate as shown in Figure 7.

Since the copper cylinder is a key conductive component of the copper-steel composite structure of the cathode roller for lithium foil, the copper cylinder serves as a key conductive carrier. The inner surface of the copper cylinder bears the radial outward tensile stress of the steel cylinder roller core, and the outer surface of the copper cylinder bears the outer layer The radial outer and inner clamping compressive stress of the titanium cylinder, so the design form of the longitudinal weld of the copper cylinder is extremely critical, not only to ensure the welding quality of the copper cylinder longitudinal weld, but also to make the weld filler metal less, reducing the titanium cylinder Welding deformation, so Figure 7 shows the form of the weld when copper plate coil welding. The weld adopts a bilateral V groove, a blunt edge of 1mm, and a copper plate thickness of dmm. Before welding, remove oil, rust and impurities from the welding groove and the surfaces on both sides. , ensure the cleanliness of the welding surface;

Then, the roundness control device of the copper cylinder is made by welding the copper plate and is then welded after hooping. The welding is done by MIG argon arc welding, with a welding current of 650-700A, an arc welding voltage of 41-44V, a welding speed of 25cm/min, and a welding wire. For SCU1898, diameter

Power supply polarity: DC reverse connection. Due to the good electrical conductivity and thermal conductivity of copper, copper dissipates heat very quickly during welding, which can easily cause cracks and other welding defects. During the welding process, cracks, pores and other defects are easy to occur. Only use appropriate welding equipment. Process specifications and corresponding welding equipment, and appropriate process methods can ensure the quality of copper welding. Since the copper cylinder is a thin-walled large-diameter part at this time, argon arc welding is more suitable. Due to the good thermal conductivity of copper, it is easy to dissipate heat. Therefore, the longitudinal weld area of the copper cylinder must be preheated to 200°C before welding. ±10℃, use a handheld thermometer to measure the temperature, use thermal insulation cotton or other insulation materials for other positions in the circumferential direction and axial direction of the copper cylinder, dry the copper wire at 350℃ for 2 hours before welding, use this method Weld the round copper plate. After welding, use thermal insulation cotton or other insulation materials to insulate the longitudinal weld of the copper plate. Let the weld slowly cool down to ensure the accuracy of the copper plate round welding.

A clamping device is installed on the outer circle of the copper cylinder. The radial gap between the copper cylinder and the hoop device is ≤0.1mm. This ensures that the welding deformation of the copper cylinder is effectively controlled when the copper cylinder is welded, and the stability of the inner hole of the copper cylinder is ensured. . By limiting the position of the copper cylinder in the radial and axial directions through the rounding device and the hooping device, the stable welding of the copper cylinder can be ensured, and the deformation of the copper cylinder during welding can be reduced while ensuring the geometric stability of the copper cylinder. Before welding the copper cylinder, it is necessary to clean the welding wire and the perimeter of the longitudinal weld groove of the copper cylinder. Use a steel wire brush, copper wire brush, etc. to clean the stains and oxides around the welding wire and the longitudinal weld groove of the copper cylinder to expose the metallic luster. During welding, the interlayer temperature between welds must be strictly controlled, and the interlayer temperature should not be lower than 100°C.

After welding, conduct flaw detection on the copper weld. The weld has no pores, slag inclusions, arc craters, arc scratches and other defects. The shape is uniform, and the weld and the copper cylinder body transition smoothly. It has passed NB/T47013.5-2015 Level I coloring flaw detection. Tested, there are no defects such as cracks; the longitudinal welds of the copper cylinder are subjected to radiographic flaw detection, and the axial length of the longitudinal welds is 100% inspected, which meets the requirements of NB/T47013.2-2015 Level II and meets the copper-steel composite cathode roller for lithium battery foil Roller core requirements.

After the copper cylinder is welded, the copper cylinder is heated with a grill or crawler heater to remove stress, thereby reducing the stress during welding of the copper cylinder and improving the dimensional stability of the copper cylinder after welding. For the copper cylinder that has been welded, insulation cotton is used at the weld to prevent rapid shrinkage of the weld and the occurrence of cracks and other defects. By insulating the copper welds, cracks caused by rapid shrinkage of welding are reduced, and welding stress is reduced. After cooling to normal temperature, remove insulation materials such as insulation cotton. For the welded copper cylinder, the rounding tooling and the hooping tooling can be heated and stress-relieved using a baking gun or a crawler heater in the circumferential and axial directions. The heating temperature is ≤200℃ and the holding time is ≤30min. It can be further processed. Eliminate the stress generated during welding and ensure the size and temperature resistance of the copper cylinder. The roundness of the copper cylinder using this method can be controlled to ≤0.5mm.

After the copper cylinder welded by this method is uniformly heated to remove stress at the circumferential, axial and longitudinal welds, the rounding tooling can be disassembled, and the rounding fastening force of the copper cylinder can be removed by removing the pins on the rounding plate. Remove the rounding device and the outer hooping device will not move. At this time, the copper cylinder maintains good roundness.

Then place the hooping device 7 in an upright position, that is, the axis of the copper cylinder is placed perpendicular to the ground, the copper cylinder with the hooping device is fastened to the vertical lathe working platform, and the inner hole of the copper cylinder is finely machined, because the copper cylinder The roundness of the cylinder is ≤0.5mm, and the inner hole of the copper cylinder can be fully processed by finishing turning the copper cylinder ≤0.6mm on one side. After the copper cylinder is finished, the inner hole size of the copper cylinder must be accurately measured to facilitate the cathode roller. The outer circle of the steel cylinder is processed according to the matching of the inner hole of the copper cylinder. Through this method, consistent processing of the inner hole size of the copper cylinder can be achieved, which facilitates batch processing of cathode rollers with this structure.

After the inner hole of the copper cylinder is finished, it is placed in the hot charging furnace together with the hooping device 7 and heated to an appropriate temperature. The interference assembly between the copper cylinder and the finished outer circle of the steel cylinder can be achieved, ensuring that the copper cylinder The close fit with the outer circle of the steel cylinder ensures the conductivity uniformity of the high-precision copper-steel composite cathode roller.

After the copper cylinder outer circle hoop device 7 is disassembled, the outer circle of the copper cylinder of the copper-steel composite cathode roller is precision turned to ensure the uniformity and consistency of the thickness of the copper layer of the conductive outer circle of the copper-steel composite cathode roller, thereby ensuring Conductive uniformity of high-precision copper-steel composite cathode rollers.

Finally, the titanium cylinder is coaxially mounted on the outer peripheral surface of the copper cylinder of the copper-steel composite cathode roller core to complete the processing of the cathode roller for lithium battery foil.

For example: the thickness of the copper plate is 8mm, the length is 6232mm, and the copper cylinder coil welding diameter

Width 1400mm. Weight is about 621Kg.

The copper plate is processed according to the theoretical length, and the grooves on both sides of the longitudinal weld of the corresponding copper plate roll are processed according to Figure 5. After the processing is completed, the W12CNC-35×2000 four-roller plate rolling machine is used to stack, pre-bend, and Roll round. During the rolling process, pay attention to the alignment of the copper plate and the inclination of the copper plate ≤ 1mm. Pre-bend the copper plate and then roll it accurately to prepare for the copper plate rolling.

The rolled copper plate is first put on the rounding tool, and then the outer circle of the rolled copper cylinder is assembled with the outer circle hoop tool. The hoop tool assembles two semicircular structures into a full circle structure. The hoop device assembles the copper cylinder. Closely fit the hoop. After hooping, pass through the axial fixing plate at the joint and tighten with screws. Check the radial gap between the copper cylinder and the rounding plate of the rounding device ≤ 0.1mm. Check the radial gap between the copper cylinder and the rounding plate. The radial gap between the inner holes of the hoop device is ≤0.1mm.

Before welding the copper cylinder, clean the welding wire and the perimeter of the longitudinal weld groove of the copper cylinder. Use a steel wire brush, copper wire brush, etc. to clean the stains and oxides around the welding wire and the longitudinal weld groove of the copper cylinder to expose the metallic luster.

Before welding the copper cylinder, use a track heater to preheat the longitudinal weld area of the copper cylinder to 200℃±10℃, use a handheld thermometer to measure the temperature, and use thermal insulation cotton to insulate other positions in the circumferential direction and axial direction of the copper cylinder. Dry the copper wire at 350°C for 2 hours before welding. Preheat the copper cylinder before welding, and dry the copper wire at 350°C for 2 hours before welding.

After the rolled copper cylinder is hooped using a rounding tool and a hooping tool, the rolled copper plate is welded longitudinally as shown in Figure 5 using MIG argon arc welding with a welding current of 650-700A and an arc welding voltage of 41-44V. , welding speed 25cm/min, wire diameter

Power supply polarity: DC reverse connection, staggered symmetrical welding method is used inside and outside the copper plate longitudinal weld. During welding, the interlayer temperature between welds must be strictly controlled, and the interlayer temperature should not be lower than 100°C. After welding, the longitudinal welding seam of the copper plate should be insulated with thermal insulation cotton and other materials to allow the welding seam to slowly cool down to room temperature, which can ensure the accuracy of the round welding of the copper plate.

After the copper cylinder is welded, the copper cylinder is heated with a crawler heater to remove stress. The heating temperature is ≤200°C and the holding time is ≤30 minutes to further reduce the stress of the copper cylinder welding.

Remove the inner hole rounding device of the copper cylinder without disassembling the hooping device on the outer circumference of the copper cylinder. Place the hooping device in an upright state, that is, place the axis of the copper cylinder perpendicular to the ground. The copper cylinder with the hooping device is fastened and turned vertically. On the working platform, perform fine turning on the inner hole of the copper cylinder. At this time, the roundness of the copper cylinder is detected to be 0.3mm. By fine turning 0.5mm on one side of the copper cylinder, all the inner holes of the copper cylinder can be processed to the light. The copper cylinder is finely turned. Finally, accurately measure the inner hole size of the copper cylinder so that the outer circle of the cathode roller steel cylinder can be processed according to the inner hole of the copper cylinder. Through this method, the inner hole size of the copper cylinder can be processed with consistency, which facilitates batch processing of cathode rollers with this structure.

After the inner hole of the copper cylinder is finished, it is placed in a hot charging furnace together with the outer hoop tooling and heated to an appropriate temperature to achieve the interference assembly between the copper cylinder and the outer circle of the finished steel cylinder, ensuring that the copper cylinder The close fit with the outer circle of the cathode roller steel cylinder ensures the conductivity uniformity of the high-precision copper-steel composite cathode roller.

For the copper-steel composite cathode roller of the hot-loaded copper cylinder, the outer circle hoop device of the copper cylinder is disassembled, and the outer circle of the copper cylinder of the copper-steel composite cathode roller is finely machined to ensure the conductive outer circle copper layer of the copper-steel composite cathode roller. The thickness is uniform and consistent, thus ensuring the conductivity uniformity of the high-precision copper-steel composite cathode roller.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above-mentioned embodiments are illustrative and should not be construed as limitations of the present invention. Those of ordinary skill in the art will not deviate from the principles and purposes of the present invention. Under the circumstances, the above-described embodiments can be changed, modified, replaced and modified within the scope of the present invention.

Claims (10)

1. A copper plate coiling and welding roundness control device, which is characterized by: including a shaft, a rounding device, a hooping device, and a copper cylinder for coiling and welding of copper plates; the copper cylinder is a copper cylinder formed by coiling and welding of copper plates;

   The rounding assembly includes a steel end plate and a rounding plate. The steel end plate is a circular flat plate structure, and the rounding plate is a flat plate with an arc-shaped outer edge on one side; several rounding plates are evenly distributed in the circumferential direction through fastening pins. At the outer edge of the end face of the steel end plate, and the outer arcs of several rounding plates are located on the same circle, and the diameter of the circle is equal to the inner diameter of the copper cylinder; multiple rounding components are welded to the shaft along the axial direction to form a rounding The device is coaxially installed in the copper cylinder and used to ensure the roundness of the inner surface of the copper cylinder;

   The hoop device is a hollow cylindrical structure composed of annular ribs and straight ribs. The multiple annular ribs are coaxial and evenly distributed along the axial direction. The multiple straight ribs are along the outer peripheral surfaces of the multiple rings. Uniformly distributed; the cylindrical structure is divided into two semi-cylindrical structures, the connection between the two semi-cylindrical structures is fastened by screws, and a gap is opened at the connection as a welding window; the hoop device is the same as The shaft is sleeved on the outer surface of the copper cylinder to ensure the roundness of the outer surface of the copper cylinder and prevent welding deformation.
2. The copper plate coil welding roundness control device according to claim 1, characterized in that: a plurality of relief holes are opened along the circumferential direction on the end surface of the steel end plate.
3. The copper plate coil welding roundness control device according to claim 1, characterized in that three of the rounding components are welded to the shaft at equal intervals.
4. The copper plate coiling and welding roundness control device according to claim 1, characterized in that: the round supporting plates have a fan-shaped structure, and 12 supporting round plates are evenly distributed along the axial direction on each steel end plate; The coaxiality between the circumference of the arc surface and the axis is ≤0.05mm.
5. The copper plate coiling and welding roundness control device according to claim 1, characterized in that: the gap between the inner circumferential surface of the hooping device and the outer surface of the copper cylinder is ≤0.1mm.
6. A method for preparing a copper cylinder using the copper plate coil welding roundness control device according to any one of claims 1 to 5, characterized in that the specific steps are as follows:

   Step 1: Calculate the length L of the copper plate before rolling based on the size of the copper cylinder to be processed. The formula is as follows:

   L＝πd-2.8t

   Among them, d is the middle diameter of the copper plate roll, t is the thickness of the plate;

   Step 2: Bending and rolling the copper plate through three rollers on the plate rolling machine, and then processing the welding groove at the longitudinal welding seam of the copper plate;

   Step 3: Install the rounding device coaxially in the rounded copper plate, and the hooping device is coaxially clamped on the outer circumferential surface of the rounded copper plate. The radial gap between the rounded copper plate and the hooping device is ≤0.1mm; through the The rounding device and the hooping device realize the radial and axial position limiting of the rolled round copper plate, and at the same time ensure that the longitudinal weld seam is located at the welding window of the hooping device;

   Step 3: Before welding, remove oil, rust and impurities from the welding groove and both sides of the surface to ensure the welding surface is clean;

   Step 4: First, locally preheat the longitudinal weld of the rolled copper plate to above 200±10°C, and then perform welding to obtain a copper cylinder. After welding, implement thermal insulation and slow cooling; after welding, disassemble the rounding device;

   Step 5: Heat and stress-relieve the longitudinal welds at the welding point of the copper cylinder. Use the flames of three air guns to bake along the circumferential and axial directions of the copper cylinder. Heat to 200°C and bake for 20 minutes to reduce the stress generated during welding of the copper cylinder. stress.
7. The method for preparing a copper cylinder with a copper plate coil welding roundness control device according to claim 6, characterized in that in the second step, the weld adopts a bilateral V-shaped groove on both inner and outer sides and a bilateral X-shaped groove with blunt edges. Bevel, ensure the consistency of the bevel size, the blunt edge is 1mm.
8. The method for preparing a copper cylinder with a copper plate coil welding roundness control device according to claim 6, characterized in that in step four, argon arc welding (MIG) is used to weld and meet the flaw detection requirements.
9. The method for preparing a copper cylinder with a copper plate coil welding roundness control device according to claim 6, characterized in that in step five, the alternative method of stress relief is to use a track heater to weld the longitudinal welds of the copper cylinder and The tooling is heated, the heating temperature is controlled at 200℃±10℃, and the heat preservation time is 20min.
10. A method for preparing a cathode roller for lithium battery foil, characterized in that: the cathode roller includes a titanium layer, a copper layer, and a steel layer in order from the outside to the inside; the titanium layer, the copper layer, and the steel layer are all cylindrical structures, The copper cylinder is prepared by the copper plate coil welding roundness control device of claim 1, and its roundness is ≤0.5mm;

    The specific steps of the preparation method are as follows:

    Step 1: Carry out finishing machining on the inner hole of the welded copper cylinder to meet the assembly requirements of the cathode roller;

    Step 2: Put the hooping device and the finished copper cylinder into a hot charging furnace or use a baking gun to heat the copper cylinder and hooping device as a whole. The copper cylinder and tooling will expand due to heat. After meeting the hot charging requirements, the cathode roller The steel cylinder roller core is installed inside the copper cylinder to meet the requirements of high-precision copper-steel composite cathode roller;

    Step 3: After the copper cylinder is hot-loaded into the steel cylinder core of the cathode roller, the hoop device is disassembled, and the copper cylinder and the copper blocking plate are welded to the cathode roller core to realize the copper-steel composite to meet the conductive requirements;

    Step 4: After completing the welding in step 3, perform fine turning on the outer circle of the copper cylinder of the copper-steel composite cathode roller core. The outer circle of the copper cylinder should be finely turned ≤0.5mm on one side to ensure the conductivity of the copper-steel composite cathode roller core. The thickness uniformity of the copper layer and the accuracy of the copper-steel composite of the copper-steel composite roller core;

    Step 5: Coaxially set the titanium cylinder on the outer peripheral surface of the copper-steel composite cathode roller core copper cylinder to complete the processing of the cathode roller for lithium battery foil.

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