Stamping die for cylindrical shell of battery and forming equipment of stamping die

Abstract

The invention discloses a stamping die of a battery cylindrical shell and forming equipment of the stamping die, relates to the technical field of new energy, and aims to solve the technical problems that in the prior art, a traditional stamping driving mode and a traditional die structure are often adopted, so that the stress concentration coefficient is high when a plate deforms, materials are prone to being torn, and the production yield is reduced. Comprising an upper die and a lower die. Through the two-section movement of the upper die and the double-step variable-taper structure of the lower die, the edge of a metal plate forms uniform adduction in the initial deformation stage through the combination of a low-speed large taper angle at the first flaring step, and the stress concentration coefficient is reduced compared with that of a traditional process; and at the second flaring step, the speed is reduced, the pressure is increased, the material strain rate is controlled within the optimal range, and the material tearing risk caused by the too high strain rate is avoided. Through an improved stamping driving mode and a die structure, stress distribution is uniform when a plate deforms, damage in the stamping process is avoided, and the production yield is increased.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and more specifically, to a stamping die for a battery cylindrical shell and a forming device thereof. Background Art

[0002] With the booming new energy industry, cylindrical batteries have become a mainstream power device thanks to their high energy density, compact size, and portability. Cylindrical batteries primarily consist of a cylindrical steel shell, a roll core, and a cap. The cylindrical steel shell plays a crucial role in isolating and protecting the roll core, and its quality directly impacts battery performance and safety. Consequently, extremely stringent requirements are placed on the manufacturing precision and efficiency of cylindrical battery shells. Currently, cylindrical battery shells generally adopt a stamping forming process, that is, a thin steel plate is placed on a forming device, and the steel plate is stamped into a forming mold by means of stamping. After demolding, the required cylindrical battery shell is obtained.

[0003] However, existing technologies often use traditional stamping drive modes and die structures. The single-shot stamping process of traditional processes results in high stress concentration coefficients at the edges of metal sheets during deformation. Due to a lack of optimized control over the material's strain rate, traditional processes are prone to material tearing during the stamping process due to excessive strain rates, which in turn reduces production yields. In light of this, we propose a stamping die and forming equipment for cylindrical battery casings. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology, adapt to actual needs, and provide a stamping die and forming equipment for a battery cylindrical shell to solve the technical problem that the current technology often adopts the traditional stamping drive mode and die structure, which leads to a high stress concentration coefficient when the plate is deformed, easily causing material tearing and reducing the production yield.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a stamping die for a cylindrical battery shell and a forming device thereof, comprising an upper die and a lower die; The upper die stroke is a two-stage moving path; The opening of the lower mold is provided with a double-step variable taper structure, which is divided into a first flaring step and a second flaring step, and the end of the second flaring step is connected to a processing and forming step, which matches the size of the cylindrical shell, and the transition between the first flaring step, the second flaring step and the processing and forming step is set as a transition curved surface; The first flaring step has a taper angle of 10-15° and a height of 3-5 mm, and the second flaring step has a taper angle of 3-8° and a height of 2-3 mm; The moving speed of the upper die in the first expansion stage is 10-15 mm / s, and the pressure is 40-50 KN. When the upper die is in this section, it is used to use a low-speed large taper angle to initially retract the edge of the material and reduce the stress concentration factor; the moving speed of the upper die in the second expansion stage is 5-8 mm / s, and the pressure is 70-80 KN. When the upper die is in this section, it is used to control the strain rate by deceleration and pressurization to avoid work hardening and tearing.

[0006] Preferably, an oil inlet assembly is provided in the upper die, and the oil inlet assembly includes a pressure rod, an elastic member, a sliding groove, an extrusion channel, a second oil inlet pipe, and an oil discharge channel; The pressure rod is connected to an external fixing part through an elastic part, and the pressure rod is slidably connected in a sliding groove. The sliding groove is opened in the upper mold. The pressure rod is inserted and connected to the extrusion channel. The end of the second oil inlet pipe is connected to the extrusion channel. The starting end of the oil discharge channel is connected to the end of the extrusion channel. The end of the oil discharge channel extends through the bottom end surface of the upper mold.

[0007] Preferably, when the pressure rod is located at the starting end, the pressure rod is located at the starting end of the extrusion channel; When the pressure rod is located at the end, the pressure rod is located at the end of the extrusion channel, and the pressure rod blocks the oil discharge channel.

[0008] Preferably, the oil drainage channel is a tree-like bifurcated structure, and the tree-like bifurcated structure is vertically distributed in the upper mold. The main pipe and the terminal pipe of the tree-like bifurcated structure are respectively located at the bottom end surface of the extrusion channel and the upper mold, and the inclination angle of the inclined branch pipe of the oil drainage pipeline is between 60-72°.

[0009] Preferably, a first oil inlet pipe is provided in the lower mold, and the first oil inlet pipe is connected to two groups of oil containing grooves through two annular channels, an oil containing channel with one end open is provided on the inner side of the oil containing groove, and a pressure block is provided in the oil containing channel, the end of the pressure block is adapted to the end of the oil containing channel, both sides of the pressure block are connected to elastic bands, and the other end of the elastic band is connected to the oil containing groove, oil outlet channels are provided on both sides of the interior of the oil containing groove, and the oil outlet channels and the elastic bands are staggered, and the two groups of pressure blocks are respectively located at the transition surfaces of the first flaring step and the second flaring step.

[0010] Preferably, the outer ring of the upper mold is provided with a plurality of rectangularly distributed micro-pits, which are hemispherical structures. The micro-pits are used as oil reservoirs to provide continuous lubrication, and the lubricating oil forms oil pockets due to surface tension, which are slowly released to reduce wear or tear caused by direct metal contact.

[0011] Preferably, a convex rod is installed inside the micro-pit, the convex rod is a conical structure, and the larger end is connected to the inner wall of the micro-pit, the convex rod is provided with stepped serrations along the inclined surface, and the stepped serrations are distributed in a ring along the axis of the convex rod, the convex rod and the serrations are used to puncture the oil film when under pressure, promote the diffusion of lubricating oil to the periphery, and improve the uniformity of lubrication.

[0012] Preferably, a plurality of micropillars are provided on the inner wall of the micropit, and an array of the plurality of micropillars forms a porous structure on the inner wall of the micropit, and the porous structure is used to quickly transmit lubricating oil through capillary action and optimize the oil storage effect of the micropit.

[0013] Preferably, an oleophilic coating is provided at the center of the micro-pit, and the oleophilic coating is used to allow oil to gather in the central part of the micro-pit so that it can spread outward along the protruding rod.

[0014] A battery cylindrical shell forming device includes a stamping forming device, wherein the stamping forming device includes a shell, a first lifting drive, a first mounting plate, a second lifting drive, a second mounting plate, and a discharge channel; The first lifting drive is installed in the shell, the first mounting plate is installed at the output end of the first lifting drive, the second lifting drive is installed on the first mounting plate, the second mounting plate is installed on the second lifting drive, the second mounting plate is connected to a plurality of pressure rods, and a plurality of lower molds are installed on the discharge channel.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a two-stage moving path and a double-step variable taper structure of the lower die. The two-stage movement of the upper die distributes energy according to the deformation characteristics of the material. When the speed of the first expansion stage is 15mm / s and the pressure is 50KN, the combination of low speed and large taper angle makes the edge of the metal sheet form a uniform inward retraction in the initial deformation stage, and the stress concentration coefficient is lower than that of the traditional process, which effectively avoids the generation of edge cracks; after entering the second expansion stage, the speed is reduced to 8mm / s and the pressure is increased to 80KN. This deceleration and pressure increase method controls the material strain rate within the optimal range, so that the work hardening effect is fully utilized while avoiding the strain caused by The risk of material tearing caused by excessive rate; the double-step variable taper structure of the lower die realizes precise guidance of metal flow through differentiated cone angle and height design. The combination of 15° cone angle and 5mm height of the first flaring step provides a reasonable space for the material to undergo initial plastic deformation, allowing the edge of the sheet to smoothly transition to the second flaring step; and the design of 8° cone angle and 3mm height of the second flaring step further refines the deformation process, ensuring that the material obtains precise shape control when it approaches the final forming size. The application of transition curves eliminates the stress mutation points in the traditional step structure, making the metal flow more continuous and smooth, and improving the uniformity of wall thickness. The present invention uses an improved stamping drive mode and die structure to uniformly distribute stress during sheet deformation, avoid damage during the stamping process, and improve the production yield rate.

[0016] 2. The present invention uses an upper die oil inlet assembly and a lower die lubrication system. When the mold is closed, the upper mold moves upward, causing the pressure rod to move relative to the end of the extrusion channel along the sliding groove, gradually compressing the lubricant in the channel. The progressive pressurization causes the lubricant pressure to steadily increase from the initial 2MPa to 8MPa, ensuring that the lubricant reaches the contact surface between the mold and the material through the oil discharge channel at a stable flow rate. When the mold is opened, the pressure rod resets and the pressure is restored, and the lubricant supply is stopped. The lubricant transported by the first oil inlet pipe of the lower mold enters the oil storage tank through the annular channel. When the mold is closed and pressure is generated, the pressure block slides in the oil storage tank, causing the pressure in the oil storage tank to increase. The staggered arrangement of the oil outlet channels on both sides and the elastic band ensures that the lubricant flows into the lower mold under pressure. The present invention uses an upper die oil inlet assembly and a lower die lubrication system. When stamping is performed, the lubricating oil can be evenly distributed to the inner and outer sides of the plate, reducing the friction coefficient between the material and the mold, and effectively suppressing the generation of scratches and wrinkles.

[0017] 3. The present invention designs the oil drainage channel into a tree-like bifurcated structure with the extrusion channel as the main pipe core and multi-level branch pipes extending to the bottom end surface of the upper mold. Through bionic design and reference to the fluid distribution principle of plant roots, the lubricant can be evenly dispersed from a single inlet to the entire mold working surface. The vertical distribution of the main pipe and the terminal pipe ensures that the lubricant flows rapidly under the dual effects of gravity and pressure, and the 72° inclined branch pipe angle is optimized through fluid mechanics simulation, which not only ensures the flow rate of the lubricant, but also avoids pressure loss caused by excessive angles. The present invention forms a three-dimensional lubrication network through the tree-like bifurcated oil drainage channel, so that the uniformity error of the lubricant is controlled at a low level.

[0018] 4. The present invention forms a microscopic oil storage network by providing rectangularly distributed hemispherical micro-pits in a circular shape on the outer side of the upper mold. When the lubricant reaches the mold surface through the oil drainage channel, the micro-pits, due to the curvature difference between their hemispherical structure and the mold surface, use surface tension to lock the lubricant therein, forming a stable oil sac. The oil sac serves as a lubricant storage depot when there is no stamping load. During the stamping process, as the contact pressure between the upper mold and the material increases, the lubricant in the oil sac is slowly released under the action of capillary force to form a continuous lubricating film. The present invention effectively solves the problem of lubricant being easily squeezed out or volatilized in traditional lubrication methods through the micro-pits, thereby optimizing the lubrication effect.

[0019] 5. The present invention adds a conical convex rod and stepped serrations within the micro-pit. The convex rod is made of a high-strength, wear-resistant alloy. Its conical structure design creates a gradient distribution of lubricating oil within the micro-pit. The oil film thickness is thinner at the tip, while thicker at the root. This thickness difference generates a pressure gradient, which allows the lubricating oil to diffuse in a directional manner. The stepped serrations are arranged in a circular array along the axis of the convex rod, which can effectively puncture the oil film without damaging the mold surface. When stamping, the ink contacts the serrations and convex rod, causing multi-directional tearing and forming an oil channel. The lubricating oil diffuses to the surrounding area under the combined action of pressure difference and surface tension. The present invention, through the convex rod and serrations, can puncture the oil film of the micro-pit during stamping, allowing the lubricating oil to diffuse rapidly during stamping.

[0020] 6. The present invention sets a micro-pillar porous structure and a central oleophilic coating on the inner wall of the micro-pit. The micro-pillars evenly distributed on the inner wall of the micro-pit are made by nano-scale precision processing technology and arranged in a regular array to form a porous structure. The tiny gaps between these micro-pillars constitute countless capillary channels. With the strong capillary force, the lubricant can be quickly absorbed into the depths of the micro-pit in a short time, which greatly improves the storage efficiency of the lubricant relative to the traditional smooth surface. The central oleophilic coating adopts a special fluorosilane polymer material with a strong affinity for lubricating oil. When the lubricating oil enters the micro-pit, the oleophilic coating quickly gathers the oil to the center of the micro-pit, avoiding the accumulation or loss of the lubricating oil at the edge of the pit. The gathered lubricating oil can quickly diffuse outward along the tapered slope and serrated structure under the guidance of the convex rod to form a complete lubricating film. The present invention can further increase the efficiency of oil storage through the micro-pillars and oleophilic coating, and make the oil converge toward the convex rod at the center of the micro-pit, thereby accelerating the construction speed of the oil film. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the mold of the present invention.

[0022] Figure 2 It is a structural schematic diagram of the lower half of the lower mold of the present invention.

[0023] Figure 3 Schematic diagram of the structure of the micro-pits of the present invention.

[0024] Figure 4 It is a cross-sectional schematic diagram of the upper die of the present invention when it is not in the stamping state.

[0025] Figure 5 It is a cross-sectional schematic diagram of the upper die of the present invention when being stamped.

[0026] Figure 6 It is a structural schematic diagram of the oil discharge channel of the present invention.

[0027] Figure 7 It is a structural schematic diagram of the lower mold of the present invention.

[0028] Figure 8 It is a schematic cross-sectional view of the lower mold of the present invention.

[0029] Figure 9 It is a structural schematic diagram of the oil inlet assembly of the present invention.

[0030] Figure 10 It is a schematic cross-sectional structural diagram of the oil containing tank of the present invention.

[0031] Figure 11 It is a structural schematic diagram of the stamping forming equipment of the present invention.

[0032] Description of the numbers in the figure: 1. Upper die; 2. Lower die; 3. Oil inlet assembly; 4. Stamping equipment; 101, micro-pits; 102, convex rods; 103, saw teeth; 104, micro-pillars; 105, oleophilic coating; 201, first flaring stage; 202, second flaring stage; 203, processing and forming stage; 204, first oil inlet pipe; 205, oil tank; 206, pressing block; 207, elastic band; 208, oil outlet channel; 301, pressure rod; 302, elastic member; 303, sliding groove; 304, extrusion channel; 305, second oil inlet pipe; 306, oil discharge channel; 401. Shell; 402. First lifting drive; 403. First mounting plate; 404. Second lifting drive; 405. Second mounting plate; 406. Discharge channel. DETAILED DESCRIPTION

[0033] Example 1, as Figures 1 to 8 As shown, the present invention relates to a stamping die for a cylindrical battery shell, comprising an upper die 1 and a lower die 2; the upper die 1 has a two-stage moving path; the opening of the lower die 2 is provided with a double-step variable taper structure, which is divided into a first flaring step 201 and a second flaring step 202, and the end of the second flaring step 202 is connected to a processing and forming step 203, which matches the size of the cylindrical shell 401, and the transition between the first flaring step 201, the second flaring step 202 and the processing and forming step 203 is set as a transition curved surface; the first flaring step 201 and the second flaring step 202 are connected to the processing and forming step 203, and the processing and forming step 203 is connected to the processing and forming step 203. 01 has a cone angle of 15° and a height of 5mm, and the cone angle of the second flaring step 202 is 8° and a height of 3mm; the moving speed of the upper die 1 in the first flaring step 201 is 15mm / s, and the pressure is 50KN. When the upper die 1 is in this section, it is used to use a low-speed and large cone angle to make the edge of the material initially inward and reduce the stress concentration factor; the moving speed of the upper die 1 in the second flaring step 202 is 8mm / s, and the pressure is 80KN. When the upper die 1 is in this section, it is used to control the strain rate by deceleration and pressurization to avoid work hardening and tearing.

[0034] The present invention uses a two-stage moving path of the upper die 1 and a double-step variable taper structure of the lower die 2. The two-stage movement of the upper die 1 distributes energy according to the deformation characteristics of the material. When the first expansion stage 201 is at a speed of 15mm / s and a pressure of 50KN, the combination of low speed and large taper angle makes the edge of the metal sheet form a uniform inward retraction in the initial deformation stage, and the stress concentration coefficient is lower than that of the traditional process, which effectively avoids the generation of edge cracks; after entering the second expansion stage 202, the speed is reduced to 8mm / s and the pressure is increased to 80KN. This deceleration and pressurization method controls the material strain rate within the optimal range, so that the work hardening effect is fully utilized while avoiding the strain caused by The risk of material tearing caused by excessive rate; the double-step variable taper structure of the lower die 2 realizes precise guidance of metal flow through differentiated cone angle and height design. The combination of the first flaring step 20115° cone angle and 5mm height provides a reasonable space for the material to undergo initial plastic deformation, allowing the edge of the plate to smoothly transition to the second flaring step 202; and the design of the second flaring step 2028° cone angle and 3mm height further refines the deformation process, ensuring that the material obtains precise shape control when it is close to the final forming size. The application of the transition surface eliminates the stress mutation point in the traditional step structure, making the metal flow more continuous and smooth, and improving the uniformity of wall thickness. The present invention makes the stress distribution of the plate uniform during deformation through an improved stamping drive mode and die structure, avoids damage during the stamping process, and improves the production yield rate.

[0035] Specifically, such as Figures 7 to 10 As shown, the upper mold 1 involved in the present invention is provided with an oil inlet assembly 3, and the oil inlet assembly 3 includes a pressure rod 301, an elastic member 302, a sliding groove 303, an extrusion channel 304, a second oil inlet pipe 305, and an oil discharge channel 306; the pressure rod 301 is connected to an external fixing member through the elastic member 302, and the pressure rod 301 is slidably connected in the sliding groove 303, the sliding groove 303 is opened in the upper mold 1, the pressure rod 301 is inserted and connected to the extrusion channel 304, the end of the second oil inlet pipe 305 is connected to the extrusion channel 304, the starting end of the oil discharge channel 306 is connected to the end of the extrusion channel 304, and the end of the oil discharge channel 306 extends through the bottom end surface of the upper mold 1.

[0036] When the pressure rod 301 is at the starting end, the pressure rod 301 is located at the starting end of the extrusion channel 304 ; when the pressure rod 301 is at the ending end, the pressure rod 301 is located at the ending end of the extrusion channel 304 , and the pressure rod 301 blocks the oil discharge channel 306 .

[0037] A first oil inlet pipe 204 is provided in the lower mold 2, and the first oil inlet pipe 204 is connected to two groups of oil containing grooves 205 through two annular channels. An oil containing channel with one end open is provided on the inner side of the oil containing groove 205, and a pressure block 206 is provided in the oil containing channel. The end of the pressure block 206 is adapted to the end of the oil containing channel. Elastic bands 207 are connected to both sides of the pressure block 206, and the other end of the elastic band 207 is connected to the oil containing groove 205. Oil outlet channels 208 are provided on both sides of the interior of the oil containing groove 205, and the oil outlet channels 208 and the elastic band 207 are staggered. The two groups of pressure blocks 206 are respectively located at the transition surfaces of the first flaring step 201 and the second flaring step 202.

[0038] The present invention uses the oil inlet assembly 3 of the upper mold 1 and the lubrication system of the lower mold 2. When the mold is closed, the upper mold 1 moves upward, so that the pressure rod 301 moves relative to the end of the extrusion channel 304 along the sliding groove 303, gradually compressing the lubricant in the channel. The progressive pressurization makes the lubricant pressure steadily increase from the initial 2MPa to 8MPa, ensuring that the lubricant reaches the contact surface between the mold and the material through the oil discharge channel 306 at a stable flow rate. When the mold is opened, the pressure rod 301 resets and the pressure is restored, and the supply of lubricant is stopped; the lubricant transported by the first oil inlet pipe 204 of the lower mold 2 enters the oil containing groove 205 through the annular channel. When the mold is closed and pressure is generated, the pressure block 206 slides in the oil containing channel, causing the pressure in the oil containing groove 205 to increase. The staggered arrangement of the oil outlet channels 208 and the elastic band 207 on both sides ensures that the lubricant flows into the lower mold 2 under the action of pressure. The present invention uses the oil inlet assembly 3 of the upper die 1 and the lubrication system of the lower die 2 to evenly distribute the lubricating oil to the inner and outer sides of the plate during stamping, thereby reducing the friction coefficient between the material and the die and effectively suppressing the generation of scratches and wrinkles.

[0039] It is worth noting that if Figures 4 to 6 As shown, the oil drainage channel 306 involved in the present invention is a tree-like bifurcated structure, and the tree-like bifurcated structure is vertically distributed in the upper mold 1. The main pipe and the terminal pipe of the tree-like bifurcated structure are respectively located at the extrusion channel 304 and the bottom end surface of the upper mold 1, and the inclination angle of the inclined branch pipe of the oil drainage pipeline is between 72°.

[0040] The present invention designs the oil drainage channel 306 into a tree-like bifurcated structure, with the extrusion channel 304 as the main pipe core and multiple branch pipes extending toward the bottom surface of the upper mold 1. Through bionic design and reference to the fluid distribution principle of plant roots, the lubricant can be evenly dispersed from a single inlet to the entire mold working surface. The vertical distribution of the main pipe and the terminal pipe ensures that the lubricant flows rapidly under the dual effects of gravity and pressure, and the 72° inclined branch pipe angle is optimized through fluid mechanics simulation, which not only ensures the flow rate of the lubricant, but also avoids pressure loss caused by excessive angles. The present invention forms a three-dimensional lubrication network through the tree-like bifurcated oil drainage channel 306, so that the uniformity error of the lubricant is controlled at a low level.

[0041] Further, such as Figures 1 to 3 As shown, the outer ring of the upper mold 1 involved in the present invention is provided with one hundred rectangularly distributed micro-pits 101, and the micro-pits 101 are hemispherical structures. The micro-pits 101 are used as an oil reservoir to provide continuous lubrication, and the lubricating oil forms oil pockets due to surface tension, which is slowly released to reduce wear or tear caused by direct contact between the metals.

[0042] The present invention forms a microscopic oil storage network by providing rectangularly distributed hemispherical micro-pits 101 in an annular shape on the outside of the upper mold 1. When the lubricant reaches the mold surface through the oil discharge channel 306, the micro-pits 101, due to the curvature difference between their hemispherical structure and the mold surface, use surface tension to lock the lubricant therein, forming a stable oil sac. The oil sac serves as a lubricant storage depot when there is no stamping load. During the stamping process, as the contact pressure between the upper mold 1 and the material increases, the lubricant in the oil sac is slowly released under the action of capillary force to form a continuous lubricating film. The present invention effectively solves the problem of lubricant being easily squeezed out or volatilized in traditional lubrication methods through the micro-pits 101, thereby optimizing the lubrication effect.

[0043] Further, if Figure 3 As shown, the micro-pit 101 involved in the present invention is internally installed with a convex rod 102, which is a conical structure, and the larger end is connected to the inner wall of the micro-pit 101, and the convex rod 102 is provided with stepped serrations 103 along the inclined surface, and the stepped serrations 103 are annularly distributed along the axis of the convex rod 102. The convex rod 102 and the serrations 103 are used to puncture the oil film when subjected to pressure, thereby promoting the diffusion of lubricating oil to the periphery and improving lubrication uniformity.

[0044] The present invention adds a conical convex rod 102 and a stepped serration 103 in the micro-pit 101. The convex rod 102 is made of a high-strength wear-resistant alloy. Its conical structure design makes the lubricating oil form a gradient distribution in the micro-pit 101. The oil film thickness is thinner at the tip part and thicker at the root area. This thickness difference generates a pressure gradient, which enables the directional diffusion of the lubricating oil. The stepped serration 103 is arranged in a ring array along the axis of the convex rod 102, which can effectively pierce the oil film without damaging the mold surface. When stamping, the ink contacts the serration 103 and the convex rod 102 to produce multi-directional tearing, forming an oil channel. The lubricating oil diffuses to the surrounding area under the combined action of pressure difference and surface tension. The present invention, through the convex rod 102 and serration 103, can pierce the oil film of the micro-pit 101 during stamping, so that the lubricating oil can diffuse rapidly during stamping.

[0045] Furthermore, Figure 3As shown, one hundred micropillars 104 are provided on the inner wall of the micropit 101 involved in the present invention, and the array of one hundred micropillars 104 forms a porous structure on the inner wall of the micropit 101. The porous structure is used to quickly transmit lubricating oil through capillary action and optimize the oil storage effect of the micropit 101.

[0046] An oleophilic coating 105 is provided at the center of the micro-dimple 101 . The oleophilic coating 105 is used to allow oil to gather in the center of the micro-dimple 101 so as to spread outward along the protruding rod 102 .

[0047] The present invention arranges a porous structure of micropillars 104 and a central oleophilic coating 105 on the inner wall of the micropit 101. The micropillars 104 evenly distributed on the inner wall of the micropit 101 are made by nano-level precision processing technology and are arranged in a regular array to form a porous structure. The tiny gaps between these micropillars 104 constitute countless capillary channels. With the strong capillary force, the lubricating oil can be quickly absorbed into the deep of the micropit 101 in a short time, so that the storage efficiency of the lubricant is greatly improved compared with the traditional smooth surface; the central oleophilic coating 105 adopts a special fluorosilane polymer material, which has a strong affinity for lubricating oil. When the lubricating oil enters the micropit 101, the oleophilic coating 105 quickly gathers the oil to the center of the micropit 101 to prevent the lubricating oil from accumulating or losing at the edge of the pit. The gathered lubricating oil can be guided by the convex rod 102 and can quickly diffuse outward along the conical slope and the sawtooth 103 structure to form a complete lubricating film. The present invention can further increase the efficiency of oil storage through the micro-pillars 104 and the oleophilic coating 105, and make the oil converge toward the convex rod 102 at the center of the micro-pit 101, thereby accelerating the construction speed of the oil film.

[0048] like Figure 11 As shown, a forming device for a battery cylindrical shell includes a stamping forming device 4, which includes a shell 401, a first lifting drive 402, a first mounting plate 403, a second lifting drive 404, a second mounting plate 405, and a discharge channel 406; the first lifting drive 402 is installed in the shell 401, the first mounting plate 403 is installed at the output end of the first lifting drive 402, the second lifting drive 404 is installed on the first mounting plate 403, the second mounting plate 405 is installed on the second lifting drive 404, the second mounting plate 405 is connected to thirty pressure rods 301, and thirty lower molds 2 are installed on the discharge channel 406.

[0049] The forming equipment is also provided with a cutting tool and a structure for pressing the plate, both of which adopt common structures on the market.

[0050] The present invention drives the upper mold 1 to move by the first lifting drive 402 and the second lifting drive 404, so that the upper mold 1 can achieve two-stage movement.

[0051] The embodiments disclosed in the present invention are preferred embodiments, but are not limited to them. Ordinary technicians in this field can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. As long as they do not deviate from the spirit of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A stamping die for a cylindrical battery shell, characterized in that: comprising an upper die (1) and a lower die (2); The upper mold (1) has a two-stage moving path; The opening of the lower mold (2) is provided with a double-step variable taper structure, the double-step variable taper structure is divided into a first flaring step (201) and a second flaring step (202), and the end of the second flaring step (202) is connected to a processing and forming step (203), the processing and forming step (203) matches the size of the cylindrical shell (401), and the transition between the first flaring step (201), the second flaring step (202) and the processing and forming step (203) is set as a transition curved surface; The first flaring step (201) has a cone angle between 10-15° and a height of 3-5 mm, and the second flaring step (202) has a cone angle between 3-8° and a height of 2-3 mm; The upper die (1) moves at a speed of 10-15 mm / s and a pressure of 40-50 KN in the first expansion stage (201). When the upper die (1) is in this stage, it is used to initially retract the edge of the material through a low-speed large taper angle, thereby reducing the stress concentration factor. The upper die (1) moves at a speed of 5-8 mm / s and a pressure of 70-80 KN in the second expansion stage (202). When the upper die (1) is in this stage, it is used to control the strain rate through deceleration and pressurization to avoid work hardening and tearing.

2. A stamping die for a battery cylindrical shell according to claim 1, characterized in that: An oil inlet assembly (3) is provided in the upper die (1), and the oil inlet assembly (3) comprises a pressure rod (301), an elastic member (302), a sliding groove (303), an extrusion channel (304), a second oil inlet pipe (305), and an oil discharge channel (306); The pressure rod (301) is connected to an external fixing member through an elastic member (302), and the pressure rod (301) is slidably connected in a sliding groove (303). The sliding groove (303) is opened in the upper mold (1). The pressure rod (301) is inserted into and connected to the extrusion channel (304). The end of the second oil inlet pipe (305) is connected to the extrusion channel (304). The starting end of the oil discharge channel (306) is connected to the end of the extrusion channel (304). The end of the oil discharge channel (306) extends through the bottom end surface of the upper mold (1).

3. The stamping die for a cylindrical battery shell according to claim 2, characterized in that: When the pressing rod (301) is located at the starting end, the pressing rod (301) is located at the starting end of the extrusion channel (304); When the pressure rod (301) is located at the end, the pressure rod (301) is located at the end of the extrusion channel (304), and the pressure rod (301) blocks the oil discharge channel (306).

4. The stamping die for a cylindrical battery shell according to claim 2, characterized in that: The oil discharge channel (306) is a tree-like bifurcated structure, and the tree-like bifurcated structure is vertically distributed in the upper mold (1). The main pipe and the terminal pipe of the tree-like bifurcated structure are respectively located at the bottom end surface of the extrusion channel (304) and the upper mold (1). The inclination angle of the inclined branch pipe of the oil discharge pipeline is between 60-72 degrees.

5. The stamping die for a cylindrical battery shell according to claim 1, characterized in that: A first oil inlet pipe (204) is provided in the lower mold (2), and the first oil inlet pipe (204) is connected to two groups of oil containing grooves (205) through two annular channels. An oil containing channel with one end open is provided on the inner side of the oil containing groove (205), and a pressure block (206) is provided in the oil containing channel. The end of the pressure block (206) is adapted to the end of the oil containing channel. Both sides of the pressure block (206) are connected to elastic bands (207), and the other end of the elastic band (207) is connected to the oil containing groove (205). Both sides of the interior of the oil containing groove (205) are provided with oil outlet channels (208), and the oil outlet channels (208) and the elastic band (207) are staggered. The two groups of pressure blocks (206) are respectively located at the transition surface of the first flaring step (201) and the second flaring step (202).

6. The stamping die for a cylindrical battery shell according to claim 1, characterized in that: The outer ring of the upper die (1) is provided with a plurality of rectangularly distributed micro-pits (101), the micro-pits (101) being a hemispherical structure, and the micro-pits (101) are used as an oil reservoir to provide continuous lubrication, and the lubricating oil forms oil pockets due to surface tension, which is slowly released to reduce wear or tear caused by direct metal contact.

7. The stamping die for a cylindrical battery shell according to claim 6, characterized in that: A convex rod (102) is installed inside the micro-pit (101), the convex rod (102) is a conical structure, and the larger end is connected to the inner wall of the micro-pit (101), the convex rod (102) is provided with stepped saw teeth (103) along the inclined surface, and the stepped saw teeth (103) are annularly distributed along the axis of the convex rod (102), and the convex rod (102) and the saw teeth (103) are used to puncture the oil film when subjected to pressure, so as to promote the diffusion of lubricating oil to the periphery and improve lubrication uniformity.

8. The stamping die for a cylindrical battery shell according to claim 6, characterized in that: A plurality of micropillars (104) are provided on the inner wall of the micro-pit (101), and an array of the plurality of micropillars (104) forms a porous structure on the inner wall of the micro-pit (101). The porous structure is used to quickly transmit lubricating oil through capillary action and optimize the oil storage effect of the micro-pit (101).

9. The stamping die for a cylindrical battery shell according to claim 6, characterized in that: An oleophilic coating (105) is provided at the center of the micro-pit (101), and the oleophilic coating (105) is used to allow oil to gather in the center of the micro-pit (101), so that it can spread outward along the protruding rod (102).

10. A battery cylindrical shell forming device, which is suitable for the battery cylindrical shell stamping die according to claim 9, characterized in that: The stamping and forming device (4) includes a housing (401), a first lifting drive (402), a first mounting plate (403), a second lifting drive (404), a second mounting plate (405), and a discharge channel (406); The first lifting drive (402) is installed in the shell (401), the first mounting plate (403) is installed at the output end of the first lifting drive (402), the second lifting drive (404) is installed on the first mounting plate (403), the second mounting plate (405) is installed on the second lifting drive (404), the second mounting plate (405) is connected to a plurality of pressure rods (301), and a plurality of lower molds (2) are installed on the discharge channel (406).

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