Contact type casting piece double-face cooling system and method

Abstract

According to the contact type cast piece double-face cooling system, a cooling medium flowing circularly is contained in a chilling roller, a leaning roller and a tensioning roller are arranged close to the chilling roller, the leaning roller and the tensioning roller are in transmission connection through a cooling belt, the cooling belt is provided with an arc face concentric with the outer surface of the chilling roller, and a cooling area allowing a cast piece to penetrate is formed between the arc face and the chilling roller. The spraying direction of the nozzles faces the inner surface of the cooling zone. The two surfaces of the casting piece are synchronously cooled through the chilling roller and the cooling belt correspondingly, rapid and uniform cooling of the casting piece is achieved, and the consistency of the thickness of a diaphragm finished product can be improved. And a large amount of white oil can be extruded on the surface of the casting piece through the opposite pressing effect of the chilling roller and the cooling belt, and the content of the white oil in the subsequent working procedure is reduced, so that oil spots and thin points on the surface of the diaphragm are reduced, and the production qualification rate of the diaphragm is improved.

Description

Technical Field

[0001] The invention relates to the field of diaphragm production and manufacturing, and further to a contact-type casting double-sided cooling system and method. Background Art

[0002] Micropore preparation technology is the core of the production process of lithium-ion battery separators. The production process of lithium battery separators is divided into two categories: dry production process and wet production process. The wet process is the mainstream production process, and the casting process is one of the indispensable processes in the wet production process of lithium battery separators. It is extremely important. In the casting stage, the melt extruded from the die head is cooled into a casting by a chilled roller. Due to the different cooling rates on the two sides of the casting, the thickness consistency of the finished diaphragm is poor. The utility model patent with application number 2022225428850 discloses a casting cooling device for lithium battery separators, which cools one side of the casting by a chilled roller and the other side of the casting by cold air. Although the device can achieve double-sided cooling of the casting, it still has the following shortcomings: some of the white oil on the casting will drip into the wind hood. In order to discharge the white oil from the wind hood, the device has an oil leakage hole on the wind hood, but this is equivalent to adding a diversion outlet to the wind hood, which makes the airflow in the wind hood unstable, reduces the overall airflow velocity of the cold air channel, and causes the cooling rate of the casting to be slower. Summary of the invention

[0003] In view of the above technical problems, the object of the present invention is to provide a contact-type double-sided cooling system and method for the cast sheet, which can achieve rapid and uniform cooling of the cast sheet.

[0004] In order to achieve the above-mentioned purpose, the contact-type double-sided cooling system for castings provided by the present invention comprises a front cooling device and a back cooling device, the front cooling device comprises a chilling roller, the chilling roller is filled with a circulating cooling medium, the back cooling device comprises a back roller, a tensioning roller, a cooling belt and a nozzle, the back roller and the tensioning roller are arranged close to the chilling roller, the back roller and the tensioning roller are connected by the cooling belt transmission, the cooling belt has an arc surface concentric with the outer surface of the chilling roller, a cooling zone allowing the casting to penetrate is formed between the arc surface and the chilling roller, and the spraying direction of the nozzle is toward the inner surface of the cooling belt.

[0005] In some embodiments, the back cooling device also includes a liquid collecting tank and a heat exchanger. The liquid collecting tank is arranged in the accommodating space enclosed by the cooling belt. A water spray pipe with the nozzle installed is provided in the liquid collecting tank. The liquid collecting tank, the water spray pipe and the heat exchanger are connected by a pipeline to form a circulation loop of the coolant. A water pump is provided on the circulation loop.

[0006] In some embodiments, the back cooling device also includes a liquid suction mechanism, which includes a liquid suction roller and an extrusion head. The liquid suction roller has a sponge layer, and the sponge layer is in contact and connected with the inner surface of the cooling belt. The extrusion head is attached to one side surface of the sponge layer, and the extrusion head is in surface contact with the sponge layer.

[0007] In some embodiments, the liquid suction mechanism further includes a partition, and the nozzle and the liquid suction roller are respectively located on both sides of the partition and separated by the partition.

[0008] In some embodiments, the cooling belt includes a main body portion and a pair of side portions, both of which are annular, the main body portion has the arc surface concentric with the outer surface of the chilled roller, and the pair of side portions are respectively arranged on both sides of the main body portion in the width direction and located on the outside of the chilled roller.

[0009] In some embodiments, the back side cooling device includes a nozzle group, and the nozzle group is arranged in a containing space enclosed by the cooling belt, and the nozzle group includes a plurality of nozzles spaced apart and distributed along the width direction of the cooling belt.

[0010] In some embodiments, the spraying direction of the nozzle is toward the cooling zone.

[0011] In some embodiments, the back side cooling device comprises a plurality of nozzle groups, and the plurality of nozzle groups are spaced apart and distributed around the cooling zone.

[0012] In some embodiments, the system further comprises a scraper, wherein the scraper is located below the chilled roller and abuts against the cooling belt.

[0013] The present invention also proposes a casting double-sided cooling method, which uses the contact casting double-sided cooling system as described above, and the method comprises the following steps: Adjust the gap between the chill roller and the cooling belt to make it equal to the set thickness of the casting; spraying the coolant toward the inner surface of the cooling belt through the nozzle; The chilling roller is driven to rotate, and the melt extruded from the die head is transformed into a casting sheet after contacting the chilling roller. The casting sheet is attached to the chilling roller and rotates with the chilling roller, and enters the cooling zone formed by the chilling roller and the cooling belt. In the cooling zone, the two surfaces of the casting sheet are cooled respectively by the chilling roller and the cooling belt.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The contact-type double-sided cooling system and method of the casting proposed in the present invention, firstly, synchronously cools the two surfaces of the casting by means of a chilling roller and a cooling belt, respectively, so as to achieve rapid and uniform cooling of the casting, which helps to improve the consistency of the thickness of the finished diaphragm. Secondly, white oil is injected from the inlet end of the extruder as a solvent, mixed with the powder and heated, and then flows out from the lip of the die head through the melt pipe, and is cooled by a chilling roller to form a casting. At this time, the white oil has been integrated into the casting, and a small amount is attached to the surface of the casting. A large amount of white oil can be squeezed out on the surface of the casting through the counter-pressure of the chilling roller and the cooling belt, thereby reducing the white oil content in the subsequent process, thereby reducing the oil spots and thin spots on the surface of the diaphragm, and improving the qualified rate of diaphragm production. In addition, the extruded white oil can also be guided to the oil receiving box by the cooling belt, which helps to realize the recovery and reuse of the white oil while maintaining the cleanliness of the production workshop floor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0016] Figure 1 It is a schematic structural diagram of a contact-type casting double-sided cooling system according to an embodiment of the present invention.

[0017] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle and back cooling device.

[0018] Figure 3 yes Figure 1 Schematic diagram of part of the structure of the middle cooling zone.

[0019] Figure 4 yes Figure 1 Schematic diagram of the structure of the liquid suction mechanism.

[0020] Description of Figure Numbers: Die head 1; chill roller 2; support roller 3; tension roller 4; cooling belt 5; liquid collecting tank 6; manifold 7; water spray pipe 8; heat exchanger 9; water pump 10; scraper 11; casting sheet 12; partition 13; liquid suction roller 14; roller shaft 141; sponge layer 142; extrusion head 15; accommodating space 16; cooling zone 17; nozzle 18. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0022] Please refer to Figure 1-4 A contact-type double-sided cooling system for a casting sheet according to an embodiment of the present invention comprises a front cooling device and a back cooling device, wherein the front cooling device and the back cooling device are respectively used to cool the front and back sides of the casting sheet 12 to achieve rapid and uniform cooling of the casting sheet 12.

[0023] It can be understood that the front and back of the casting sheet 12 are two surfaces of the casting sheet 12 that are opposite to each other. For example, when the front cooling device includes a chilling roller 2, the front of the casting sheet 12 refers to the surface of the casting sheet 12 close to the chilling roller 2, and the back of the casting sheet 12 refers to the surface of the casting sheet 12 away from the chilling roller 2. When the back cooling device includes a chilling roller 2, the front of the casting sheet 12 refers to the surface of the casting sheet 12 away from the chilling roller 2, and the back of the casting sheet 12 refers to the surface of the casting sheet 12 close to the chilling roller 2. The present application does not specifically limit the position of the chilling roller 2. As an example, in this embodiment, the front cooling device includes a chilling roller 2, which is a roller used to cool the casting sheet 12, and can quickly cool the high-temperature melt extruded by the die head 1 to below the glass transition temperature, so that the melt is transformed from a viscous flow state to an amorphous solid casting sheet 12, to avoid crystallization affecting subsequent stretching.

[0024] The back cooling device includes a back roller 3, a tension roller 4 and a cooling belt 5. The back roller 3 and the tension roller 4 are rollers arranged close to the chill roller 2. The extension direction of the back roller 3 and the tension roller 4 is consistent with the extension direction of the chill roller 2. In order to distinguish, the roller close to the die head 1 is defined as the back roller 3, and the other roller is defined as the tension roller 4. The tension roller 4 is located lower than the back roller 3. The tension roller 4 and the back roller 3 are connected by the cooling belt 5. The cooling belt 5 is an annular belt with a relatively thin thickness. The cooling belt 5 has an arc surface concentric with the outer surface of the chill roller 2. The arc surface of the cooling belt 5 cooperates with the chill roller 2 to form a cooling zone 17. When the casting 12 enters the cooling zone 17, the two surfaces of the casting 12 are in contact with the chill roller 2 and the cooling belt 5 respectively. In this way, the front side of the casting 12 can be cooled by the chill roller 2, and the back side of the casting 12 can be cooled by the cooling belt 5, so as to achieve rapid and uniform cooling of both sides of the casting 12.

[0025] In this embodiment, the cooling belt 5 can be a stainless steel belt or a chrome-plated alloy steel. The cooling belt 5 should have excellent high thermal conductivity, corrosion resistance and thermal stability, ensuring rapid and uniform cooling of the casting 12 while being able to resist the erosion of white oil on the casting 12 and maintain dimensional stability at high temperatures. In addition, the outer surface of the cooling belt 5 can also be mirror-polished with high precision to reduce the friction resistance on the surface of the casting 12, prevent the casting 12 from adhering and ensure the uniformity of the thickness of the final diaphragm product.

[0026] In this embodiment, the cooling belt 5 includes a main body 51 and a pair of side portions 52, both of which are annular. The main body 51 has an arc surface concentric with the outer surface of the chill roller 2. The gap between the arc surface of the main body 51 and the chill roller 2 allows the casting 12 to pass through, and the arc surface of the main body 51 and the chill roller 2 cooperate to form the cooling zone 17. The width dimension of the main body 51 is slightly larger than the axial dimension of the chill roller 2. The pair of side portions 52 are respectively arranged on both sides of the width direction of the main body 51 and protrude from the main body 51. In this way, after the casting 12 enters the cooling zone 17, the casting 12 is cooled by the chill roller 2 and the cooling belt 5, and is also squeezed by the chill roller 2 and the cooling belt 5. The white oil on the casting 12 is isolated on the main body 51 by the side portion 52 of the cooling belt 5. The white oil will move with the main body 51 and finally leave the cooling belt 5 and enter the oil receiving box (not shown) on one side of the tension roller 4.

[0027] The cooling device of this embodiment cools the two surfaces of the casting 12 through the chilling roller 2 and the cooling belt 5 respectively. In order to ensure the cooling efficiency of the casting 12, the temperature of the chilling roller 2 and the cooling belt 5 should be maintained within a stable range. In this embodiment, the chilling roller 2 is equipped with a cooling medium that can circulate, such as water or oil. The temperature of the chilling roller 2 can be kept stable through heat exchange between the cooling medium and the chilling roller 2. In this embodiment, the back cooling device also includes a nozzle group, which is arranged in the accommodating space 16 formed by the cooling belt 5. The nozzle group includes a plurality of nozzles 18 spaced apart along the width direction of the cooling belt 5. The nozzles 18 can spray a coolant, such as water or oil, onto the inner surface of the cooling belt 5 to keep the temperature of the cooling belt 5 stable. This embodiment does not limit the spraying direction of the nozzle 18. The spraying direction of the nozzle 18 can be toward the cooling zone 17 formed by the chilled roller 2 and the cooling belt 5, or away from the cooling zone 17 formed by the chilled roller 2 and the cooling belt 5, or can be other directions except the above two directions. It is preferred that the spraying direction of the nozzle 18 is toward the cooling zone 17 formed by the chilled roller 2 and the cooling belt 5, which can minimize the temperature change of the cooling belt 5 in the cooling zone 17.

[0028] Since the spraying area of ​​the nozzle 18 is certain and cannot completely cover the cooling belt 5 in the cooling zone 17, in order to achieve uniform cooling of the cooling belt 5 in the cooling zone 17, in this embodiment, the back cooling device may include multiple groups of nozzle groups, and the multiple groups of nozzle groups are spaced around the cooling zone 17 to spray coolant to different positions of the cooling belt 5, so as to ensure the uniformity of the temperature of the cooling belt 5 in the cooling zone 17.

[0029] In this embodiment, the back cooling device may further include a liquid collecting tank 6 and a heat exchanger 9. The liquid collecting tank 6 is a tank for collecting and storing coolant. The liquid collecting tank 6 is arranged in a containing space 16 formed by the cooling belt 5. The liquid collecting tank 6 is provided with water spray pipes 8 having the same number as the nozzle group. The water spray pipes 8 extend along the width direction of the cooling belt 5. The multiple nozzles 18 of the nozzle group are spaced apart along the extension direction of the water spray pipes 8. The water spray pipes 8 are connected by a manifold 7. The manifold 7 may be arranged in the liquid collecting tank 6 or outside the liquid collecting tank 6. This embodiment does not make specific restrictions. The liquid collecting tank 6, the heat exchanger 9 and the manifold 7 are connected by a pipeline, forming a circulation loop of the coolant. A water pump 10 is arranged on the circulation loop. The heat exchanger 9 is a device for performing heat exchange between the coolant supplied by the collecting tank 6 and the cooling water. The coolant can flow from the collecting tank 6 side to the heat exchanger 9 side. In the heat exchanger 9, the temperature of the coolant and the cooling water is reduced due to heat exchange. The cooled coolant flows from the heat exchanger 9 side to the manifold 7 side, and is sprayed onto the inner surface of the cooling belt 5 through the nozzle 18 on the water spray pipe 8 to ensure that the temperature of the cooling belt 5 at the cooling zone 17 is maintained within a stable range.

[0030] In this embodiment, a liquid level sensor is also provided in the liquid collecting tank 6. The liquid level sensor is a sensor for detecting the position of the coolant interface in the liquid collecting tank 6. The water level information of the coolant can be obtained in time through the liquid level sensor so that on-site workers can replenish the coolant in the liquid collecting tank 6 in time.

[0031] In this embodiment, the back cooling device may further include a liquid suction mechanism, which is used to clean the coolant remaining on the inner surface of the cooling belt 5. The liquid suction mechanism is arranged in the accommodating space 16 formed by the cooling belt 5, and the liquid suction mechanism includes a liquid suction roller 14 and an extrusion head 15. The liquid suction roller 14 includes an inner roller shaft 141 and a sponge layer 142 wrapped outside the roller shaft 141. The end of the roller shaft 141 can be rotatably connected to the liquid collecting tank 6 through a bearing or the like. The sponge layer 142 is in contact with the inner surface of the cooling belt 5. When the cooling belt 5 moves, the liquid suction roller 14 is driven to rotate around its axis. The sponge layer 142 on the liquid suction roller 14 continuously absorbs the working liquid remaining on the inner surface of the cooling belt 5 during the circular motion. In this embodiment, the extrusion head 15 is attached to one side surface of the sponge layer 142, and its working surface directly covers a local area of ​​the sponge layer 142, and the two are in a surface contact state. The sponge layer 142 of the liquid suction roller 14 can be squeezed by the extrusion head 15, so as to squeeze out the coolant locked in the sponge layer 142 to keep the sponge layer 142 in an unsaturated state, so that the sponge layer 142 can continuously absorb the coolant, and avoid the sponge layer 142 being saturated and unable to effectively absorb the coolant, and the coolant squeezed out by the extrusion head 15 will fall back into the liquid collecting tank 6 for recovery and reuse.

[0032] In addition, in order to prevent the working liquid sprayed by the nozzle 18 from being directly absorbed by the suction roller 14, a partition 13 may be provided in the liquid collecting tank 6, the partition 13 extending in the vertical direction, and the nozzle 18 and the suction roller 14 are respectively located on both sides of the partition 13. In this way, the nozzle 18 and the suction roller 14 can be separated by the partition 13, so that the suction roller 14 can absorb the residual working liquid on the inner surface of the cooling belt 5 without interference.

[0033] In this embodiment, the contact type casting double-sided cooling system also includes an oil removal device, which is used to clean the white oil remaining on the outer surface of the cooling belt 5. The oil removal device includes a scraper 11, which extends along the width direction of the cooling belt 5, close to or against the outer surface of the cooling belt 5 wrapped around the tensioning roller 11. The scraper 11 can be used to clean the white oil attached to the surface of the cooling belt 5, so that the casting 12 is closely attached to the cooling belt 5, and bubbles are prevented from being generated due to uneven attachment of the casting 12, and eventually the product has lines or fractures, thereby ensuring the quality and output of the diaphragm product. In this embodiment, the scraper 11 can be made of silicone sheet material. The material selection of the scraper 11 utilizes the excellent performance of the material of the silicone sheet, and is not easy to soften under the premise of ensuring the scraping effect, and has high wear resistance, which can ensure the oil scraping effect on the cooling belt 5.

[0034] The cast sheet 12 in this embodiment can be formed into a finished diaphragm after being processed by stretching, extraction, drying and other processes. There is a certain relationship between the thickness of the diaphragm and the thickness of the cast sheet 12. When the required thickness of the diaphragm changes, the thickness of the cast sheet 12 also needs to be reset. In order to ensure that the two sides of the cast sheet 12 can be attached to the chilling roller and the cooling belt 5 respectively, the gap between the chilling roller 2 and the cooling belt 5 needs to be equal to the thickness of the cast sheet 12. In this embodiment, the chilling roller 2 is installed on a bracket, and the bracket is connected to a driving mechanism, and is driven by the driving mechanism to perform linear motion to approach or move away from the cooling belt 5. The driving mechanism can adopt a power device such as a cylinder or a hydraulic cylinder, and the direction of the linear motion of the bracket should be perpendicular or nearly perpendicular to the direction of the axis connecting the roller 3 and the tensioning roller 4.

[0035] The following specifically introduces a cooling method using the above-mentioned contact type casting double-sided cooling system, which includes the following steps: Adjust the gap between the chill roller 2 and the cooling belt 5 so that the gap is equal to the set thickness of the casting sheet 12; The cooling liquid is sprayed toward the inner surface of the cooling belt 5 through the nozzle 18, and the falling cooling liquid automatically falls into the collecting tank 6. The cooling liquid in the collecting tank 6 is pumped to the nozzle 18 through the water pump 10 to circulate the cooling liquid; The chilling roller 2 is driven to rotate, and the melt extruded from the die head 1 is transformed into a casting sheet 12 after contacting the chilling roller 2. The casting sheet 12 is attached to the chilling roller 2 and rotates with the chilling roller 2, and enters the cooling zone 17 formed by the chilling roller 2 and the cooling belt 5. In the cooling zone 17, the two surfaces of the casting sheet 12 are cooled by the chilling roller 2 and the cooling belt 5 respectively.

[0036] As described above, the contact-type casting double-sided cooling system and method proposed by the present invention, first, synchronously cools the two surfaces of the casting 12 through the chilling roller 2 and the cooling belt 5, respectively, to achieve rapid and uniform cooling of the casting 12, which helps to improve the consistency of the thickness of the finished diaphragm. Secondly, white oil is injected from the inlet end of the extruder as a solvent, mixed with the powder and heated, and then flows out from the lip of the die head through the melt pipe, and is cooled by the chilling roller 2 to form the casting 12. At this time, the white oil has been integrated into the casting 12, and a small amount is attached to the surface of the casting 12. Through the pressure of the chilling roller 2 and the cooling belt 5, a large amount of white oil can be squeezed out on the surface of the casting 12, reducing the white oil content in the subsequent process, thereby reducing the oil spots and thin spots on the diaphragm surface, and improving the qualified rate of diaphragm production. In addition, the extruded white oil can also be guided to the oil receiving box through the cooling belt 5, which helps to achieve the recovery and reuse of the white oil while maintaining the cleanliness of the production workshop floor.

[0037] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A contact type casting double-sided cooling system, characterized in that: It includes a front cooling device and a back cooling device. The front cooling device includes a chilling roller, and the chilling roller is filled with a circulating cooling medium. The back cooling device includes a back roller, a tensioning roller, a cooling belt and a nozzle. The back roller and the tensioning roller are arranged close to the chilling roller, and the back roller and the tensioning roller are connected by the cooling belt. The cooling belt has an arc surface concentric with the outer surface of the chilling roller. A cooling zone allowing the casting to penetrate is formed between the arc surface and the chilling roller, and the coolant spraying direction of the nozzle is toward the inner surface of the cooling belt.

2. The contact type casting double-sided cooling system according to claim 1, characterized in that: The back cooling device also includes a liquid collecting tank and a heat exchanger. The liquid collecting tank is arranged in the accommodating space enclosed by the cooling belt. A water spray pipe with the nozzle installed is provided in the liquid collecting tank. The liquid collecting tank, the water spray pipe and the heat exchanger are connected by a pipeline to form a circulation loop of the coolant. A water pump is provided on the circulation loop.

3. The contact type casting double-sided cooling system according to claim 1, characterized in that: The back cooling device also includes a liquid suction mechanism, which includes a liquid suction roller and an extrusion head. The liquid suction roller has a sponge layer, and the sponge layer is in contact and connected with the inner surface of the cooling belt. The extrusion head is attached to one side surface of the sponge layer, and the extrusion head and the sponge layer are in surface contact.

4. The contact type casting double-sided cooling system according to claim 3 is characterized in that: The liquid suction mechanism further comprises a partition, and the nozzle and the liquid suction roller are respectively located on both sides of the partition and separated by the partition.

5. The contact type casting double-sided cooling system according to claim 1, characterized in that: The cooling belt includes a main body and a pair of side portions, both of which are annular. The main body has the arc surface concentric with the outer surface of the chilled roller. The pair of side portions are respectively arranged on both sides of the main body in the width direction and located outside the chilled roller.

6. The contact type casting double-sided cooling system according to claim 1, characterized in that: The back side cooling device comprises a nozzle group, and the nozzle group is arranged in a containing space enclosed by the cooling belt, and the nozzle group comprises a plurality of nozzles distributed at intervals along the width direction of the cooling belt.

7. The contact type casting double-sided cooling system according to claim 6, characterized in that: The spraying direction of the nozzle is toward the cooling zone.

8. The contact type casting double-sided cooling system according to claim 7, characterized in that: The back side cooling device comprises a plurality of nozzle groups, and the plurality of nozzle groups are distributed at intervals around the cooling zone.

9. The contact type casting double-sided cooling system according to claim 1, characterized in that: The system further includes a scraper located below the chilled roller and against the cooling belt.

10. A contact type casting double-sided cooling method, characterized in that: The contact type casting double-sided cooling system according to any one of claims 1 to 9 is adopted, and the method comprises the following steps: Adjust the gap between the chill roller and the cooling belt to make it equal to the set thickness of the casting; spraying the coolant toward the inner surface of the cooling belt through the nozzle; The chilling roller is driven to rotate, and the melt extruded from the die head is transformed into a casting sheet after contacting the chilling roller. The casting sheet is attached to the chilling roller and rotates with the chilling roller, and enters the cooling zone formed by the chilling roller and the cooling belt. In the cooling zone, the two surfaces of the casting sheet are cooled respectively by the chilling roller and the cooling belt.

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