Stamping die for battery cylindrical shell and forming equipment thereof

Abstract

The application discloses a stamping die of a battery cylindrical shell and a forming equipment thereof, relates to the technical field of new energy, and aims to solve the technical problem that in current technology, a traditional stamping driving mode and a die structure are often adopted, a stress concentration coefficient is high when a plate is deformed, material tearing is easily caused, and a production yield is reduced, and the stamping die comprises an upper die and a lower die. Through two-section movement of the upper die and a double-ladder variable taper structure of the lower die, in a first flaring stage, a combination of low speed and a large taper angle causes the edges of the metal plate to uniformly contract in an initial deformation stage, and the stress concentration coefficient is reduced compared with a traditional process; in a second flaring stage, the speed is reduced and the pressure is increased, a material strain rate is controlled within an optimal range, and the risk of material tearing caused by a too high strain rate is avoided. Through the improved stamping driving mode and the die structure, stress distribution is uniform when the plate is deformed, damage in the stamping process is avoided, and the production yield is improved.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and more specifically, to a stamping die for a cylindrical battery casing and its forming equipment. Background Technology

[0002] In the current booming development of the new energy industry, cylindrical batteries have become one of the mainstream power devices due to their advantages such as high energy density, small size, and portability. Cylindrical batteries mainly consist of a cylindrical steel shell structure, a wound core structure, and a capping structure. The cylindrical steel shell structure plays a crucial role in isolating and protecting the wound core, and its quality directly affects the battery's performance and safety. Therefore, extremely stringent requirements are placed on the manufacturing precision and production efficiency of cylindrical battery casings.

[0003] Currently, cylindrical battery casings are generally produced using a stamping process, which involves placing thin steel plates on a forming machine and stamping them into a mold. After demolding, the desired cylindrical battery casing is obtained.

[0004] However, existing technologies often employ traditional stamping drive modes and mold structures. The single-pass stamping process of traditional techniques results in high stress concentration at the edges of the metal sheet during deformation. Due to a lack of optimized control over the material strain rate, traditional processes are prone to material tearing during stamping due to excessive strain, thus reducing production yield. Therefore, we propose a stamping die and its forming equipment for a cylindrical battery casing. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art, adapt to practical needs, and provide a stamping die and forming equipment for a cylindrical battery casing. This solves the technical problem that the current technology often uses traditional stamping drive mode and die structure, which leads to a high stress concentration coefficient when the sheet metal is deformed, easily causing material tearing and reducing the yield rate.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a stamping die for a cylindrical battery casing and its forming equipment, comprising an upper die and a lower die;

[0007] The upper mold travels in a two-stage movement path;

[0008] 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. The end of the second flaring step is connected to a processing and forming step. The processing and forming step matches the size of the cylindrical shell. The transition between the first flaring step, the second flaring step and the processing and forming step is set as a transition surface.

[0009] The cone angle of the first flared step is between 10-15° and the height is 3-5mm; the cone angle of the second flared step is between 3-8° and the height is 2-3mm.

[0010] The upper die moves at a speed of 10-15 mm / s and a pressure of 40-50 KN in the first flaring stage. When the upper die is in this stage, it is used to initially reduce the material edge by using a low speed and large cone angle, thereby reducing the stress concentration factor. When the upper die is in the second flaring stage, it moves at a speed of 5-8 mm / s and a pressure of 70-80 KN. When the upper die is in this stage, it is used to control the strain rate by decelerating and increasing the pressure, thereby avoiding work hardening tearing.

[0011] Preferably, the upper mold is provided with an oil inlet assembly, which includes a pressure rod, an elastic element, a sliding groove, an extrusion channel, a second oil inlet pipe, and an oil outlet channel;

[0012] The pressure rod is connected to an external fixing member through an elastic element, 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 beginning of the oil outlet channel is connected to the end of the extrusion channel. The end of the oil outlet channel extends through the bottom end face of the upper mold.

[0013] Preferably, when the pressure bar is located at the beginning, the pressure bar is located at the beginning of the extrusion channel;

[0014] When the pressure rod is at the end, it is located at the end of the extrusion channel and blocks the oil discharge channel.

[0015] Preferably, the oil discharge channel has a tree-like branching structure, and the tree-like branching structure is vertically distributed in the upper mold. The main pipe and the end pipe of the tree-like branching structure are located at the bottom end face of the extrusion channel and the upper mold, respectively. The inclination angle of the inclined branch pipes of the oil discharge channel is between 60-72°.

[0016] Preferably, the lower mold is provided with a first oil inlet pipe, which is connected to two sets of oil receiving grooves through two annular channels. The inner side of the oil receiving groove is provided with an oil receiving channel with one end open, and a pressure block is provided in the oil receiving channel. The end of the pressure block is adapted to the end of the oil receiving channel. Elastic bands are connected to both sides of the pressure block, and the other end of the elastic band is connected to the oil receiving groove. Oil outlet channels are opened on both sides of the interior of the oil receiving groove, and the oil outlet channels are offset from the elastic bands. The two sets of pressure blocks are located at the transition surface of the first flared step and the second flared step, respectively.

[0017] Preferably, the outer annular portion of the upper mold has several rectangularly distributed micro-dimples. The micro-dimples are hemispherical in shape and serve as oil reservoirs to provide continuous lubrication. They also allow the lubricating oil to form oil pockets due to surface tension, which slowly release the oil and reduce wear or tear caused by direct metal-to-metal contact.

[0018] Preferably, a protruding rod is installed inside the micro-pit. The protruding rod has a conical structure, with its larger end connected to the inner wall of the micro-pit. The protruding rod has stepped serrations distributed along the inclined surface, and the stepped serrations are distributed in a ring along the axis of the protruding rod. The protruding rod and serrations are used to puncture the oil film when subjected to pressure, causing the lubricating oil to diffuse to the surrounding area and improving the uniformity of lubrication.

[0019] Preferably, the inner wall of the micro-pit is provided with a plurality of micropillars, and the array of the plurality of micropillars forms a porous structure on the inner wall of the micro-pit. The porous structure is used to rapidly transfer lubricating oil through capillary action and optimize the oil storage effect of the micro-pit.

[0020] Preferably, an oleophilic coating is provided at the center of the micro-pit, which is used to allow oil to collect in the center of the micro-pit, thereby enabling it to spread outward along the protrusion.

[0021] A forming device for a cylindrical battery casing includes a stamping forming device, wherein the stamping forming device includes a casing, a first lifting drive, a first mounting plate, a second lifting drive, a second mounting plate, and a discharge channel;

[0022] The first lifting drive is installed inside the housing, 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 several pressure rods, and several lower molds are installed on the discharge channel.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. This invention utilizes a two-stage moving path and a double-step variable taper structure in the lower die. The two-stage movement of the upper die distributes energy according to the material deformation characteristics. In the first flaring stage, with a speed of 15 mm / s and a pressure of 50 kN, the combination of low speed and large taper angle causes the edge of the metal sheet to uniformly taper in the initial deformation stage, reducing the stress concentration coefficient compared to traditional processes and effectively preventing edge cracks. Upon entering the second flaring stage, the speed decreases to 8 mm / s while the pressure increases to 80 kN. This deceleration and pressure increase method controls the material strain rate within the optimal range, fully utilizing the work hardening effect while avoiding strain-induced damage. The invention mitigates the risk of material tearing due to excessively high yield rates. The double-step variable taper structure of the lower die, through differentiated taper angles and heights, precisely guides metal flow. The combination of a 15° taper angle and a 5mm height in the first flaring step provides reasonable space for initial plastic deformation, allowing the sheet metal edge to smoothly transition to the second flaring step. The 8° taper angle and 3mm height in the second flaring step further refine the deformation process, ensuring precise shape control as the material approaches its final formed size. The application of transition surfaces eliminates stress abruptness points in traditional stepped structures, resulting in smoother, more continuous metal flow and improved wall thickness uniformity. This invention, through an improved stamping drive mode and die structure, ensures uniform stress distribution during sheet metal deformation, avoids damage during stamping, and improves production yield.

[0025] 2. This invention utilizes an upper die oil inlet assembly and a lower die lubrication system. When the die is closed, the upper die moves upward, causing the pressure rod to move relative to the end of the extrusion channel along the sliding groove, gradually compressing the lubricant within the channel. This gradual pressurization ensures the lubricant pressure steadily increases from an initial 2MPa to 8MPa, guaranteeing a stable flow rate of lubricant through the oil outlet channel to the die-material contact surface. When the die opens, the pressure rod resets, and the lubricant supply stops. The lubricant supplied by the first oil inlet pipe of the lower die enters the oil reservoir through an annular channel. When the die closes and generates pressure, the pressure block slides within the oil reservoir, increasing the pressure. The staggered arrangement of the oil outlet channels on both sides and the elastic band ensures that the lubricant flows into the lower die under pressure. This invention, through the upper die oil inlet assembly and the lower die lubrication system, enables the lubricant to be evenly distributed on the inner and outer sides of the sheet metal during stamping, reducing the coefficient of friction between the material and the die and effectively suppressing scratches and wrinkles.

[0026] 3. This invention designs the oil drainage channel as a tree-like branching structure. The tree-like branching structure takes the extrusion channel as the core and extends to the bottom face of the upper mold with multiple branch pipes. Through biomimetic design, referring to the fluid distribution principle of plant roots, the lubricant can be evenly dispersed from a single inlet to the entire working surface of the mold. The vertical distribution of the main pipe and the end pipes ensures that the lubricant flows rapidly under the dual action of gravity and pressure. The 72° inclined branch pipe angle has been optimized by fluid dynamics simulation, which not only ensures the flow speed of the lubricant, but also avoids pressure loss caused by excessive angle. This invention forms a three-dimensional lubrication network through the tree-like branching oil drainage channel, so that the uniformity error of the lubricant is controlled at a low level.

[0027] 4. This invention forms a microscopic oil storage network by creating rectangularly distributed hemispherical micro-dimples around the outer ring of the upper die. When the lubricant reaches the die surface through the oil discharge channel, the micro-dimples, due to the curvature difference between their hemispherical structure and the die surface, use surface tension to lock the lubricant within, forming a stable oil bladder. The oil bladder acts as a lubricant reservoir when there is no stamping load. During the stamping process, as the contact pressure between the upper die and the material increases, the lubricant in the oil bladder is slowly released under capillary force, forming a continuous lubricating film. This invention effectively solves the problem of lubricant being easily squeezed out or evaporated in traditional lubrication methods through micro-dimples, thus optimizing the lubrication effect.

[0028] 5. This invention adds a tapered protrusion and stepped serrations within the micro-dimples. The protrusion is made of a high-strength, wear-resistant alloy, and its tapered structure creates a gradient distribution of lubricating oil within the micro-dimples. The oil film is thinner at the tip and thicker at the root, creating a pressure gradient that directionally diffuses the lubricating oil. The stepped serrations are arranged in a ring array along the protrusion's axis, effectively piercing the oil film without damaging the mold surface. During stamping, the ink contacts the serrations and protrusion, causing multi-directional tearing and forming oil channels. Under the combined action of pressure difference and surface tension, the lubricating oil diffuses to the surrounding area. This invention, through the protrusion and serrations, can pierce the oil film in the micro-dimples during stamping, allowing the lubricating oil to diffuse rapidly.

[0029] 6. This invention utilizes a micropillar porous structure and a central oleophilic coating on the inner wall of the micro-pit. The micropillars, uniformly distributed on the inner wall of the micro-pit, are manufactured using nanoscale precision machining and arranged in a regular array to form a porous structure. The tiny gaps between these micropillars constitute countless capillary channels. Through powerful capillary forces, lubricating oil can be rapidly drawn into the depths of the micro-pit in a short time, significantly improving lubricant storage efficiency compared to traditional smooth surfaces. The central oleophilic coating uses a special fluorosilane polymer material with extremely strong affinity for lubricating oil. When lubricating oil enters the micro-pit, the oleophilic coating quickly gathers the oil to the center of the pit, preventing lubricating oil from accumulating or flowing away at the pit's edges. Guided by the protruding rods, the gathered lubricating oil can rapidly diffuse outward along the conical slope and serrated structure, forming a complete lubricating film. This invention, through the micropillars and oleophilic coating, further increases oil storage efficiency and causes the oil to converge towards the protruding rods at the center of the micro-pit, accelerating the oil film formation speed. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the mold of the present invention.

[0031] Figure 2 This is a schematic diagram of the lower half of the lower mold of the present invention.

[0032] Figure 3 This is a schematic diagram of the structure of the micro-pits in this invention.

[0033] Figure 4 This is a cross-sectional view of the upper die of the present invention when it is not in the stamping process.

[0034] Figure 5 This is a cross-sectional schematic diagram of the upper die of the present invention when it is being stamped.

[0035] Figure 6 This is a schematic diagram of the oil drain channel of the present invention.

[0036] Figure 7 This is a schematic diagram of the structure of the lower mold of the present invention.

[0037] Figure 8 This is a cross-sectional schematic diagram of the lower mold of the present invention.

[0038] Figure 9 This is a schematic diagram of the oil inlet assembly of the present invention.

[0039] Figure 10 This is a cross-sectional view of the oil tank structure of the present invention.

[0040] Figure 11 This is a schematic diagram of the stamping forming equipment of the present invention.

[0041] Explanation of the labels in the diagram:

[0042] 1. Upper die; 2. Lower die; 3. Oil inlet assembly; 4. Stamping equipment;

[0043] 101. Micro-dimples; 102. Protrusions; 103. Serrations; 104. Micropillars; 105. Oleophilic coating;

[0044] 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;

[0045] 301. Pressure bar; 302. Elastic element; 303. Sliding groove; 304. Extrusion channel; 305. Second oil inlet pipe; 306. Oil discharge channel;

[0046] 401. Housing; 402. First lifting drive; 403. First mounting plate; 404. Second lifting drive; 405. Second mounting plate; 406. Discharge channel. Detailed Implementation

[0047] Example 1, as Figures 1 to 8 As shown, the present invention relates to a stamping die for a cylindrical battery casing, comprising an upper die 1 and a lower die 2; the upper die 1 has a two-stage moving path; the lower die 2 has a double-step variable taper structure at its opening, the double-step variable taper structure being divided into a first flared step 201 and a second flared step 202, and the end of the second flared step 202 is connected to a forming step 203, the forming step 203 being dimensionally matched with the cylindrical casing 401, and the transition between the first flared step 201, the second flared step 202 and the forming step 203 being a transition surface; the first flared step 201... The cone angle of the first flared step 201 is between 15° and 5mm, and the cone angle of the second flared step 202 is between 8° and 3mm. The upper die 1 moves at a speed of 15mm / s and a pressure of 50KN when it is in the first flared step 201. When the upper die 1 is in this section, it is used to pass through the low speed and large cone angle to make the material edge initially shrink inward and reduce the stress concentration factor. The upper die 1 moves at a speed of 8mm / s and a pressure of 80KN when it is in the second flared step 202. When the upper die 1 is in this section, it is used to control the strain rate by decelerating and increasing the pressure to avoid work hardening tearing.

[0048] This invention utilizes a two-stage moving path of the upper mold 1 and a double-step variable taper structure of the lower mold 2. The two-stage movement of the upper mold 1 distributes energy according to the material deformation characteristics. In the first flaring stage 201, when acting at a speed of 15 mm / s and a pressure of 50 kN, the combination of low speed and large taper angle causes the edge of the metal sheet to form a uniform inward contraction in the initial deformation stage, reducing the stress concentration coefficient compared to traditional processes and effectively avoiding the generation of edge cracks. After entering the second flaring stage 202, the speed decreases to 8 mm / s while the pressure increases to 80 kN. This deceleration and pressure increase method controls the material strain rate within the optimal range, fully utilizing the work hardening effect while avoiding strain-induced deformation. The invention mitigates the risk of material tearing due to excessively high yield rates. The double-step variable taper structure of the lower die 2, through differentiated cone angle and height design, achieves precise guidance of metal flow. The combination of the first flared step 20115° cone angle and 5mm height provides reasonable space for initial plastic deformation, allowing the sheet metal edge to smoothly transition to the second flared step 202. The design of the second flared step 2028° cone angle and 3mm height further refines the deformation process, ensuring precise shape control of the material as it approaches the final formed size. The application of transition surfaces eliminates stress abruptness points in traditional stepped structures, making metal flow more continuous and smooth, and improving wall thickness uniformity. This invention, through an improved stamping drive mode and die structure, ensures uniform stress distribution during sheet metal deformation, avoids damage during stamping, and improves production yield.

[0049] Specifically, such as Figures 7 to 10 As shown, the upper mold 1 of the present invention is provided with an oil inlet assembly 3. The oil inlet assembly 3 includes a pressure rod 301, an elastic element 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 element through the elastic element 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 into the extrusion channel 304. The end of the second oil inlet pipe 305 is connected to the extrusion channel 304. The beginning 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 surface of the upper mold 1.

[0050] When the pressure rod 301 is at the beginning, it is located at the beginning of the extrusion channel 304; when the pressure rod 301 is at the end, it is located at the end of the extrusion channel 304 and blocks the oil discharge channel 306.

[0051] The lower mold 2 is provided with a first oil inlet pipe 204. The first oil inlet pipe 204 is connected to two sets of oil receiving grooves 205 through two annular channels. The inner side of the oil receiving groove 205 is provided with an oil receiving channel with one end open. The oil receiving channel is provided with a pressure block 206. The end of the pressure block 206 is adapted to the end of the oil receiving channel. Both sides of the pressure block 206 are connected with elastic bands 207, and the other end of the elastic bands 207 is connected to the oil receiving groove 205. Both sides of the inner side of the oil receiving groove 205 are provided with oil outlet channels 208, and the oil outlet channels 208 are offset from the elastic bands 207. The two sets of pressure blocks 206 are located at the transition surface of the first flared step 201 and the second flared step 202, respectively.

[0052] This invention utilizes 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, causing the pressure rod 301 to move relative to the end of the extrusion channel 304 along the sliding groove 303, gradually compressing the lubricant in the channel. The gradual pressurization allows the lubricant pressure to steadily increase from the initial 2MPa to 8MPa, ensuring that the lubricant reaches the mold and material contact surface 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, stopping the supply of lubricant. The lubricant delivered by the first oil inlet pipe 204 of the lower mold 2 enters the oil container 205 through the annular channel. When the mold is closed and pressure is generated, the pressure block 206 slides in the oil container channel, increasing the pressure in the oil container 205. The staggered arrangement of the oil outlet channels 208 on both sides and the elastic band 207 ensures that the lubricant flows into the lower mold 2 under pressure. The present invention, through the oil inlet assembly 3 of the upper mold 1 and the lubrication system of the lower mold 2, can make the lubricating oil evenly distributed to the inner and outer sides of the sheet metal during stamping, thereby reducing the coefficient of friction between the material and the mold and effectively suppressing the generation of scratches and wrinkles.

[0053] It is worth noting that, such as Figures 4 to 6 As shown, the oil discharge channel 306 involved in this invention has a tree-like branching structure, and the tree-like branching structure is vertically distributed in the upper mold 1. The main pipe and the end pipe of the tree-like branching structure are located at the bottom end face of the extrusion channel 304 and the upper mold 1, respectively. The inclination angle of the inclined branch pipes of the oil discharge channel 306 is between 72°.

[0054] This invention designs the oil discharge channel 306 as a tree-like branching structure. The tree-like branching structure takes the extrusion channel 304 as the main core and extends to the bottom surface of the upper mold 1 with multiple branch pipes. Through biomimetic design, referring to the fluid distribution principle of plant roots, the lubricant can be evenly dispersed from a single inlet to the entire working surface of the mold. The vertical distribution of the main and end pipes ensures that the lubricant flows rapidly under the dual action of gravity and pressure. The 72° inclined branch pipe angle has been optimized by fluid dynamics simulation, which not only ensures the flow speed of the lubricant, but also avoids pressure loss caused by excessive angle. This invention forms a three-dimensional lubrication network through the tree-like branching oil discharge channel 306, which keeps the uniformity error of the lubricant at a low level.

[0055] Furthermore, such as Figures 1 to 3 As shown, the upper mold 1 of the present invention has one hundred rectangularly distributed micro-pits 101 on its outer ring. The micro-pits 101 are hemispherical structures. The micro-pits 101 are used as oil reservoirs to provide continuous lubrication and allow the lubricating oil to form oil pockets due to surface tension, which slowly releases the oil and reduces wear or tear caused by direct metal contact.

[0056] This invention forms a microscopic oil storage network by creating rectangularly distributed hemispherical micro-dimples 101 around the outer ring of the upper die 1. When the lubricant reaches the die surface through the oil discharge channel 306, the micro-dimples 101, due to the curvature difference between their hemispherical structure and the die surface, use surface tension to lock the lubricant within, forming a stable oil bladder. The oil bladder acts as a lubricant reservoir when there is no stamping load. During the stamping process, as the contact pressure between the upper die 1 and the material increases, the lubricant in the oil bladder is slowly released under capillary force, forming a continuous lubricating film. This invention effectively solves the problem of lubricant being easily squeezed out or evaporated in traditional lubrication methods through the micro-dimples 101, thus optimizing the lubrication effect.

[0057] Furthermore, such as Figure 3 As shown, the micro-pit 101 of the present invention has a protruding rod 102 installed inside. The protruding rod 102 has a conical structure, and its larger end is connected to the inner wall of the micro-pit 101. The protruding rod 102 has stepped serrations 103 distributed along the inclined surface, and the stepped serrations 103 are distributed in a ring along the axis of the protruding rod 102. The protruding rod 102 and the serrations 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 the lubrication uniformity.

[0058] This invention adds a tapered protrusion 102 and stepped serrations 103 within the micro-recess 101. The protrusion 102 is made of a high-strength, wear-resistant alloy, and its tapered structure design creates a gradient distribution of lubricating oil within the micro-recess 101. The oil film is thinner at the tip and thicker at the root, and this thickness difference generates a pressure gradient, causing the lubricating oil to diffuse in a directional manner. The stepped serrations 103 are arranged in a ring array along the axis of the protrusion 102, effectively piercing the oil film without damaging the mold surface. During stamping, the ink comes into contact with the serrations 103 and the protrusion 102, causing multi-directional tearing and forming oil channels. Under the combined action of pressure difference and surface tension, the lubricating oil diffuses to the surrounding area. This invention, through the protrusion 102 and serrations 103, can pierce the oil film in the micro-recess 101 during stamping, allowing the lubricating oil to diffuse rapidly during the stamping process.

[0059] Furthermore, such as Figure 3 As shown, the micro-pit 101 of the present invention has one hundred micro-pillars 104 on its inner wall, and the array of one hundred micro-pillars 104 forms a porous structure on the inner wall of the micro-pit 101. The porous structure is used to quickly transfer lubricating oil through capillary action and optimize the oil storage effect of the micro-pit 101.

[0060] The center of the micro-pit 101 is provided with an oleophilic coating 105. The oleophilic coating 105 is used to allow oil to collect in the center of the micro-pit 101, so that it can spread outward along the protrusion 102.

[0061] This invention utilizes a porous structure of micropillars 104 and a central oleophilic coating 105 on the inner wall of a micro-pit 101. The micropillars 104, uniformly distributed on the inner wall of the micro-pit 101, are manufactured using nanoscale precision machining and arranged in a regular array to form a porous structure. The tiny gaps between these micropillars 104 constitute countless capillary channels. With strong capillary force, lubricating oil can be rapidly drawn into the depths of the micro-pit 101 in a short time, greatly improving the lubricant storage efficiency compared to traditional smooth surfaces. The central oleophilic coating 105 is made of a special fluorosilane polymer material, which has a strong affinity for lubricating oil. When lubricating oil enters the micro-pit 101, the oleophilic coating 105 quickly gathers the oil to the center of the micro-pit 101, preventing the lubricating oil from accumulating or flowing away at the edge of the pit. Under the guidance of the protruding rod 102, the gathered lubricating oil can rapidly diffuse outward along the conical inclined surface and the serrated structure 103 to form a complete lubricating film. The present invention, through the micropillars 104 and the oleophilic coating 105, can further increase the efficiency of oil storage and cause the oil to converge toward the protrusion 102 at the center of the micro-pit 101, thereby accelerating the construction speed of the oil film.

[0062] like Figure 11As shown, a forming device for a cylindrical battery casing includes a stamping forming device 4. The stamping forming device 4 includes a casing 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 inside the casing 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 dies 2 are installed on the discharge channel 406.

[0063] The forming equipment is also equipped with cutting tools and a structure for pressing the sheet material, both of which are common structures on the market.

[0064] The present invention drives the upper mold 1 to move by the first lifting drive 402 and the second lifting drive 404, thereby enabling the upper mold 1 to move in two stages.

[0065] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A stamping die for a cylindrical battery casing, characterized in that, Includes upper mold (1) and lower mold (2); The upper mold (1) has a two-stage movement path; The lower mold (2) has a double-step variable taper structure at its opening. The double-step variable taper structure is divided into a first flared step (201) and a second flared step (202). The end of the second flared 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). The transition between the first flared step (201), the second flared step (202), and the processing and forming step (203) is set as a transition surface. The cone angle of the first flared step (201) is between 10-15° and the height is 3-5mm; the cone angle of the second flared step (202) is between 3-8° and the height is 2-3mm. The upper die (1) moves at a speed of 10-15 mm / s and a pressure of 40-50 KN when it is in the first flaring stage (201). When the upper die (1) is in this stage, it is used to make the material edge initially shrink and reduce the stress concentration coefficient by passing through a low speed and large cone angle. The upper die (1) moves at a speed of 5-8 mm / s and a pressure of 70-80 KN when it is in the second flaring stage (202). When the upper die (1) is in this stage, it is used to control the strain rate by decelerating and increasing pressure to avoid work hardening tearing.

2. The stamping die for a cylindrical battery casing according to claim 1, characterized in that, The upper mold (1) is provided with an oil inlet assembly (3), which includes a pressure rod (301), an elastic element (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 element (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 the extrusion channel (304). The end of the second oil inlet pipe (305) is connected to the extrusion channel (304). The beginning 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 surface of the upper mold (1).

3. The stamping die for a cylindrical battery casing according to claim 2, characterized in that, When the pressure bar (301) is at the beginning, the pressure bar (301) is at the beginning of the extrusion channel (304); When the pressure rod (301) is 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 casing according to claim 2, characterized in that, The oil drain channel (306) has a tree-like branching structure, and the tree-like branching structure is vertically distributed in the upper mold (1). The main pipe and the end pipe of the tree-like branching structure are located at the bottom end face of the extrusion channel (304) and the upper mold (1), respectively. The inclination angle of the inclined branch pipe of the oil drain channel (306) is between 60-72°.

5. The stamping die for a cylindrical battery casing according to claim 1, characterized in that, The lower mold (2) is provided with a first oil inlet pipe (204). The first oil inlet pipe (204) is connected to two sets of oil tanks (205) through two annular channels. The inner side of the oil tank (205) is provided with an oil channel with one end open, and a pressure block (206) is provided in the oil channel. The end of the pressure block (206) is adapted to the end of the oil channel. Both sides of the pressure block (206) are connected with elastic bands (207), and the other end of the elastic bands (207) is connected to the oil tank (205). Both sides of the interior of the oil tank (205) are provided with oil outlet channels (208), and the oil outlet channels (208) are offset from the elastic bands (207). The two sets of pressure blocks (206) are located at the transition surface of the first flared step (201) and the second flared step (202), respectively.

6. The stamping die for a cylindrical battery casing according to claim 1, characterized in that, The outer ring of the upper mold (1) is provided with a number of rectangularly distributed micro-pits (101). The micro-pits (101) are hemispherical structures. The micro-pits (101) are used as oil reservoirs to provide continuous lubrication and allow the lubricating oil to form oil pockets due to surface tension, which slowly releases the oil and reduces wear or tear caused by direct metal contact.

7. The stamping die for a cylindrical battery casing according to claim 6, characterized in that, The micro-pit (101) is equipped with a protruding rod (102). The protruding rod (102) has a conical structure, and its larger end is connected to the inner wall of the micro-pit (101). The protruding rod (102) has stepped serrations (103) distributed along the inclined surface. The stepped serrations (103) are distributed in a ring along the axis of the protruding rod (102). The protruding rod (102) and the serrations (103) are used to puncture the oil film when subjected to pressure, so as to promote the diffusion of lubricating oil to the surrounding area and improve the lubrication uniformity.

8. The stamping die for a cylindrical battery casing according to claim 6, characterized in that, The inner wall of the micro-pit (101) is provided with a plurality of micro-pillars (104), and the array of the plurality of micro-pillars (104) forms a porous structure on the inner wall of the micro-pit (101). The porous structure is used to rapidly transfer lubricating oil through capillary action and optimize the oil storage effect of the micro-pit (101).

9. A stamping die for a cylindrical battery casing according to claim 6, characterized in that, The micro-pit (101) is provided with an oleophilic coating (105) at its center. The oleophilic coating (105) is used to allow oil to collect in the center of the micro-pit (101) so that it can spread outward along the protrusion (102).

10. A forming device for a cylindrical battery casing, applicable to the stamping die for a cylindrical battery casing as described in claim 9, characterized in that, The equipment includes a stamping forming device (4), which 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 inside the housing (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).

Images