A die structure for reducing surface tensile defects of a shell

Abstract

The present application relates to the technical field of lithium battery, and particularly relates to a concave die structure for reducing surface tensile defects of a shell, which comprises a base, a receiving ring and a core jumper. A vertical through hole is formed in the base, and the upper end of the through hole is formed into an access end. The receiving ring is arranged in the through hole and close to the access end. The inner ring surface of the receiving ring is abutted by the shell during the stretching process of the shell. The inner ring surface of the receiving ring comprises a pressure bearing section gradually narrowing inward from top to bottom and a friction section connected with the pressure bearing section. The pressure bearing section is made of die steel, and a plurality of micro holes are formed on the working surface of the pressure bearing section. The friction section is made of ceramic. The core jumper is movably arranged in the through hole for receiving the bottom end surface of the shell. A plurality of oil injection ports are formed on the outer circumferential surface of the core jumper for oil injection when passing through the pressure bearing section. The technical problem that the surface of the shell has tensile defects due to the severe friction between the shell and the surface of the concave die in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically a concave mold structure for reducing surface stretching defects in the casing. Background Technology

[0002] The casing of a lithium battery is cylindrical in shape and is formed by stamping with a mold. During the stamping process, the casing is stretched, and the diameter of the stretched casing becomes smaller and the length becomes longer until the stretching is complete. The casing generates a lot of heat during the stretching process. The existing mold structure (especially the concave mold supporting the lower end of the casing) has insufficient heat dissipation capacity, which makes the surface oil film prone to carbonization and carbon deposits. At the same time, the casing and the surface of the concave mold rub against each other intensely. If the casing material is nickel-plated steel, the nickel layer on the casing surface will peel off, and carbon deposits and nickel powder will accumulate, gradually growing and welding onto the mold, scratching the casing surface. If the casing material is aluminum, aluminum powder on the casing surface will peel off, and carbon deposits and aluminum powder will accumulate, which will also scratch the casing surface. Summary of the Invention

[0003] In order to solve the technical problem that the intense friction between the shell and the die surface in the prior art leads to tensile defects on the shell surface, this application proposes a die structure that reduces tensile defects on the shell surface, thus solving the above-mentioned technical problem.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] This invention provides a die structure for reducing surface stretching defects in a housing, comprising: a base, wherein a vertical through hole is formed in the base, and the upper end of the through hole is formed as an access end; a receiving ring, wherein the receiving ring is disposed in the through hole and close to the access end, the inner ring surface of the receiving ring is abutted by the housing during the stretching process of the housing, the inner ring surface of the receiving ring includes a pressure-bearing section that gradually narrows inward from top to bottom and a friction section that connects with the pressure-bearing section, the pressure-bearing section is made of die steel and has multiple micro-holes on its working surface, the friction section is made of ceramic; and a jumper core, wherein the jumper core is movably disposed in the through hole for receiving the bottom end face of the housing, and multiple oil spray nozzles are formed on the outer peripheral surface of the jumper core for spraying oil when passing through the pressure-bearing section.

[0006] Furthermore, the receiving ring is detachably mounted on the base.

[0007] Furthermore, the receiving ring includes a pressure-bearing body made of mold steel and a friction body made of ceramic embedded in the pressure-bearing body.

[0008] Furthermore, the embedded end of the friction body is circumferentially expanded outward to be limited by the pressure-bearing body.

[0009] Furthermore, the base includes a kit and a sleeve that enclose and limit the receiving ring. The inner ring of the kit is raised upward to form a guide portion. The lower end of the receiving ring is formed as a guide end. The receiving ring is sleeved and positioned on the guide portion through the guide end. The inner wall surface of the sleeve is attached to the outer ring surface of the receiving ring. The top end of the sleeve forms a pressure ring end that presses against the upper end of the receiving ring. The bottom end of the sleeve is fixedly connected to the outer ring of the kit.

[0010] Furthermore, a cooling channel is formed between the outer ring surface of the receiving ring and the base.

[0011] Furthermore, the receiving ring is composed of multiple inserts arranged in a ring.

[0012] Furthermore, a base block is disposed at the bottom of the through hole, and the jumper core is movably disposed on the base block via a slide rod. The slide rod passes through the base block, and a limiting member is disposed on one end of the slide rod after it passes through the base block. An elastic member is sleeved on the slide rod, and the elastic member is clamped between the jumper core and the base block. Under the combined action of the elastic member and the limiting member, the upper end face of the jumper core is limited to a position slightly higher than the receiving ring. During the stretching process of the housing, the jumper core is pressed against the base block.

[0013] Furthermore, the oil passage of the fuel injector is configured inside the jumper core, the oil inlet of the oil passage is connected to an external oil pump, and the oil sump where the oil pump is located is connected to the bottom of the through hole of the base.

[0014] Furthermore, an annular groove is formed on the outer wall surface of the top of the jumper core, and the oil injection port is disposed in the annular groove.

[0015] Based on the above technical solution, the technical effects that this invention can achieve are as follows:

[0016] The present invention provides a die structure for reducing tensile defects on the shell surface. On one hand, the portion of the inner ring surface of the receiving ring that contacts the shell is designed as a pressure-bearing section and a friction section made of two materials. The pressure-bearing section is made of die steel, possessing a certain toughness to absorb the initial impact force of the steel shell. The friction section is made of ceramic. Since the shell needs to bend and slide at the friction section, the ceramic surface is smooth, resulting in low frictional resistance when in contact with the shell. Compared to die steel, it is more wear-resistant, making it less prone to detachment from the shell-ceramic contact area (unlike nickel plating on steel or aluminum powder shedding on aluminum). In particular, ceramic is inherently less prone to cold welding with metal materials (such as steel or aluminum), which is a significant advantage, avoiding the problems associated with using steel dies (such as die steel or aluminum). The tungsten steel and the metal that falls off the shell form a weld bead, thus preventing the weld bead from scratching the shell surface. On the other hand, the working surface of the pressure-bearing section made of mold steel has multiple micro-holes to store a small amount of oil and foreign objects that fall off the shell surface. After the foreign objects fall into the micro-holes, they no longer protrude from the working surface of the pressure-bearing section. During the stamping process, the shell does not come into contact with foreign objects, and the shell surface is not easily scratched. At the same time, multiple oil spray nozzles are formed on the outer peripheral surface of the core to spray oil when passing through the pressure-bearing section, thereby periodically flushing the working surface of the pressure-bearing section and reducing the accumulation of foreign objects. This solves the technical problem in the prior art that the shell surface has tensile defects due to the severe friction between the shell and the die surface.

[0017] The die structure of the present invention for reducing the stretching defects on the shell surface has a cooling channel formed between the outer ring surface of the receiving ring and the base. The cooling medium is introduced into the cooling channel to cool the die, thereby reducing the heat accumulation generated during the stretching process after stamping and alleviating the carbonization of the oil film on the receiving ring.

[0018] The present invention provides a die structure for reducing surface tension defects in the housing. The receiving ring is composed of multiple inserts arranged in a ring. The advantage of this structure is that when a certain area on the receiving ring is worn, only the insert at the corresponding position needs to be replaced, instead of replacing the entire die, which saves time, effort, and costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the die structure for reducing tensile defects on the shell surface according to the present invention.

[0020] Figure 2 This is a schematic diagram of the die structure for reducing tensile defects on the shell surface of the present invention at the receiving ring.

[0021] Figure 3 This is a schematic diagram of the oil injection port of the jumper core of the present invention;

[0022] Figure 4 This is a schematic diagram showing the contact between the pressure-bearing section of the receiving ring of the present invention and the housing.

[0023] Figure 5 This is a schematic diagram showing the contact between the friction section of the receiving ring of the present invention and the housing.

[0024] Figure 6 This is an exploded view of the receiving ring of the present invention;

[0025] Figure 7 This is a schematic diagram of the micropores in the receiving ring of the present invention;

[0026] Figure 8 This is a schematic diagram of the shell before stretching;

[0027] Figure 9 This is a schematic diagram of the shell being stretched.

[0028] Figure 10 This is a schematic diagram of the shell after stretching.

[0029] Wherein: a-shell; 1-base, 11-through hole, 12-suite, 121-guide part, 13-sleeve body, 131-pressure ring end, 14-cooling channel, 15-base block, 16-slide rod, 161-limiting part, 17-elastic part; 2-receiving ring, 21-pressure bearing section, 211-microhole, 22-friction section, 23-pressure bearing body, 24-friction body, 25-guide end, 26-insert; 3-jump core, 31-oil injection port, 32-oil pump, 33-annular groove, 34-oil passage; 4-punch rod. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figure 1-10As shown, the present invention provides a concave mold structure for reducing surface stretching defects of a housing, including a base 1, a receiving ring 2, and a jumper core 3. A vertical through hole 11 is formed in the base 1, and the upper end of the through hole 11 is formed as an access end. The receiving ring 2 is disposed in the through hole 11 and close to the access end. The inner ring surface of the receiving ring 2 is abutted by the housing a during the stretching process of the housing a. The inner ring surface of the receiving ring 2 includes a pressure-bearing section 21 that gradually narrows inward from top to bottom and a friction section 22 that connects with the pressure-bearing section 21. The pressure-bearing section 21 is made of mold steel and has a plurality of microholes 211 on its working surface. The microholes 211 are elliptical or circular and are arranged in an array with a depth of 1-2 μm. The friction section 22 is made of ceramic. The jumper core 3 is movably disposed in the through hole 11 to receive the bottom end face of the housing a. A plurality of oil spray nozzles 31 are formed on the outer peripheral surface of the jumper core 3 to spray oil when passing through the pressure-bearing section 21.

[0032] In a preferred embodiment of the present invention, the receiving ring 2 is detachably mounted on the base 1. When the receiving ring 2 in contact with the housing a wears out, it is not necessary to replace the entire die; only the receiving ring 2 needs to be replaced, which saves time, effort, and costs.

[0033] Specifically, the base 1 includes a kit 12 that encloses and limits the receiving ring 2 and a sleeve 13. The inner ring of the kit 12 protrudes upward to form a guide portion 121. The guide surface of the guide portion 121 is inclined and faces away from the through hole 11. The lower end of the receiving ring 2 is formed as a guide end 25. The receiving ring 2 is sleeved and positioned on the guide portion 121 through the guide end 25. The inner wall surface of the sleeve 13 is attached to the outer ring surface of the receiving ring 2. The outer ring surface of the receiving ring 2 is a vertical surface. The top of the sleeve 13... A pressure ring end 131 is formed on the upper end of the receiving ring 2. Specifically, the top part of the sleeve 13 extends into the through hole 11 to form the pressure ring end 131. The shape of the pressure ring end 131 facing the inside of the through hole 11 is a profile that is wider on the outside and narrower on the inside for easy access to the housing a. The profile smoothly transitions with the working surface of the pressure bearing section 21 of the receiving ring 2. The bottom end of the sleeve 13 is fixedly connected to the outer ring of the kit 12, such as by screwing. The screwing bolt passes through the outer ring of the kit 12 and is inserted into the sleeve 13.

[0034] In a preferred embodiment of the present invention, the receiving ring 2 includes a pressure-bearing body 23 made of mold steel and a friction body 24 made of ceramic embedded in the pressure-bearing body 23.

[0035] Specifically, the embedded end of the friction body 24 is circumferentially expanded outward to be limited by the pressure-bearing body 23.

[0036] In a preferred embodiment of the present invention, an annular cooling channel 14 is formed between the outer ring surface of the receiving ring 2 and the base 1. The cooling channel 14 can be arranged on the inner wall surface of the sleeve 13 of the base 1. A sealant is applied between the receiving ring 2 and the base 1 to ensure the sealing of the cooling channel 14. A cooling medium circulates in the cooling channel 14 to cool the die. The cooling medium can be selected as cooling water to reduce the heat accumulation generated by the shell a during the stretching process after stamping and to alleviate the carbonization of the oil film on the receiving ring 2.

[0037] In a preferred embodiment of the present invention, the receiving ring 2 is composed of a plurality of inserts 26 arranged in a ring. For example, a complete receiving ring 2 can be composed of twelve inserts 26 spliced ​​together. The inserts 26 are also made of two materials: mold steel and ceramic. Adjacent inserts 26 can be interlocked, that is, all inserts 26 are assembled into the base 1 after interference fit. The advantage of this is that when a certain area on the receiving ring 2 is worn, only the insert 26 at the corresponding position needs to be replaced, instead of replacing the entire die, which saves time, effort and costs.

[0038] In a preferred embodiment of the present invention, a base block 15 is disposed at the bottom of the through hole 11. The jumper core 3 is movably disposed on the base block 15 via a slide rod 16. The slide rod 16 passes through the base block 15, and a limiting member 161 is disposed on one end of the slide rod 16 after passing through the base block 15. An elastic member 17 is sleeved on the slide rod 16. The elastic member 17 can be a spring. The elastic member 17 is clamped between the jumper core 3 and the base block 15. Under the combined action of the elastic member 17 and the limiting member 161, the upper end face of the jumper core 3 is limited to a position slightly higher than the receiving ring 2. During the stretching process of the shell a, the jumper core 3 is pressed against the base block 15. That is, when the punch 4 of the mold punches down the steel shell a, the jumper core 3 always abuts against the lower end face of the shell a under the action of the elastic member 17, thereby always supporting the shell a during the stretching process of the shell a.

[0039] In a preferred embodiment of the present invention, the oil passage 34 of the oil injection port 31 is disposed inside the jumper core 3, the oil inlet of the oil passage 34 is disposed at the lower end of the jumper core 3 and connected to the external oil pump 32, the oil inlet of the oil pump 32 is provided with a filter screen, and the oil pool where the oil pump 32 is located is connected to the bottom of the through hole 11 of the base 1, that is, the oil used to flush the working surface of the pressure section 21 is recycled.

[0040] In a preferred embodiment of the present invention, an annular groove 33 is formed on the outer wall surface of the top end of the jumper core 3, and an oil injection port 31 is disposed within the annular groove 33. In this embodiment, there are two annular grooves 33, and the oil injection ports 31 within the two annular grooves 33 are elliptical and arranged alternately.

[0041] It should be understood that the specific embodiments described above are for illustrative purposes only and are not intended to limit the scope of the invention. Obvious variations or modifications derived from the spirit of the invention are still within the protection scope of the invention.

Claims

1. A die structure for reducing tensile defects on the surface of a shell, characterized in that, include: A base (1) has a vertical through hole (11) formed inside it, and the upper end of the through hole (11) is formed as an access end; The receiving ring (2) is disposed in the through hole (11) and close to the access end. The inner ring surface of the receiving ring (2) is abutted by the housing (a) during the stretching process of the housing (a). The inner ring surface of the receiving ring (2) includes a pressure-bearing section (21) that gradually narrows inward from top to bottom and a friction section (22) that connects with the pressure-bearing section (21). The pressure-bearing section (21) is made of mold steel and has multiple micro-holes (211) on its working surface. The friction section (22) is made of ceramic. Jumper core (3), which is movably disposed in the through hole (11) to receive the bottom end face of the housing (a), and a plurality of oil injection ports (31) are formed on the outer peripheral surface of the jumper core (3) to spray oil when passing through the pressure section (21).

2. The die structure for reducing tensile defects on the shell surface according to claim 1, characterized in that, The receiving ring (2) is detachably mounted on the base (1).

3. The die structure for reducing tensile defects on the shell surface according to claim 2, characterized in that, The receiving ring (2) includes a bearing body (23) made of mold steel and a friction body (24) made of ceramic embedded in the bearing body (23).

4. The die structure for reducing tensile defects on the shell surface according to claim 3, characterized in that, The embedded end of the friction body (24) is circumferentially expanded to be limited by the pressure body (23).

5. The die structure for reducing tensile defects on the shell surface according to claim 2, characterized in that, The base (1) includes a kit (12) that encloses and limits the receiving ring (2) and a sleeve (13). The inner ring of the kit (12) is raised upward to form a guide portion (121). The lower end of the receiving ring (2) is formed as a guide end (25). The receiving ring (2) is sleeved and positioned on the guide portion (121) through the guide end (25). The inner wall surface of the sleeve (13) is attached to the outer ring surface of the receiving ring (2). The top end of the sleeve (13) forms a pressure ring end (131) that is pressed against the upper end of the receiving ring (2). The bottom end of the sleeve (13) is fixedly connected to the outer ring of the kit (12).

6. The die structure for reducing tensile defects on the shell surface according to claim 2, characterized in that, A cooling channel (14) is formed between the outer ring surface of the receiving ring (2) and the base (1).

7. The die structure for reducing tensile defects on the shell surface according to claim 2, characterized in that, The receiving ring (2) is composed of multiple inserts (26) arranged in a ring shape.

8. The die structure for reducing tensile defects on the shell surface according to claim 1, characterized in that, A base block (15) is disposed at the bottom of the through hole (11). The jumper (3) is movably disposed on the base block (15) via a slide rod (16). The slide rod (16) passes through the base block (15). A limiting member (161) is disposed on one end of the slide rod (16) after it passes through the base block (15). An elastic member (17) is sleeved on the slide rod (16). The elastic member (17) is clamped between the jumper (3) and the base block (15). Under the combined action of the elastic member (17) and the limiting member (161), the upper end face of the jumper (3) is limited to a position slightly higher than the receiving ring (2). The jumper (3) is pressed against the base block (15) during the stretching process of the housing (a).

9. The die structure for reducing tensile defects on the shell surface according to claim 8, characterized in that, The oil passage (34) of the oil injector (31) is arranged in the jumper core (3), the oil inlet of the oil passage (34) is connected to the external oil pump (32), and the oil pool where the oil pump (32) is located is connected to the bottom of the through hole (11) of the base (1).

10. The die structure for reducing tensile defects on the shell surface according to claim 1, characterized in that, An annular groove (33) is formed on the outer wall surface of the top of the jumper core (3), and the oil injection port (31) is disposed in the annular groove (33).

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