Lithium battery diaphragm wet-process line casting piece roller oil removal device and method

Abstract

According to the lithium battery diaphragm wet process line casting piece roller oil removal device, a first air nozzle is located on one side of a casting piece roller, a second air nozzle is located on the other side of the casting piece roller, a gas-liquid separator is communicated with an exhaust cavity pipeline of the second air nozzle, and a gas conveying device is arranged on a pipeline between the gas-liquid separator and the second air nozzle; an air inlet of the condenser is communicated with an air outlet pipeline of the gas-liquid separator, an air outlet of the condenser is communicated with an air inlet cavity pipeline of the first air nozzle, and an exhaust cavity of the first air nozzle is communicated with an air inlet cavity pipeline of the second air nozzle. Through three-stage treatment of gas-liquid separation, condensation purification and gas circulation, a closed system is constructed, a synergistic effect is generated, namely, oil removal, gas purification and auxiliary cooling are completed at the same time, pollution of oil mist to the environment can be reduced, meanwhile, gas recycling is achieved, energy consumption is reduced, and the environment-friendly effect is achieved. And in addition, dry cold air can synchronously assist in shaping of the casting piece, rapid and uniform cooling of the casting piece is achieved, and the consistency of the thickness of a diaphragm finished product can be improved.

Description

Technical Field

[0001] The present invention relates to the field of diaphragm production and manufacturing, and further relates to a device and method for degreasing a lithium battery diaphragm wet casting roller. Background Art

[0002] Microporous preparation technology is the core process for the production of lithium-ion battery separators. Its preparation methods are mainly divided into two technical routes: dry process and wet process. At present, the wet process occupies a dominant position in the market due to its performance advantages. The casting process, as a key link in the wet production process, directly determines the quality stability of the separator product. In this process, the melt is extruded through the die head and rapidly cooled and formed through the casting roller. However, during the process, a large amount of paraffin oil will be precipitated on the roller surface. It is worth noting that the uniformity of the distribution of paraffin oil directly affects the cooling effect of the casting. Its uneven distribution will lead to deviations in the thickness of the separator and reduce the quality of the finished product. Summary of the Invention

[0003] In response to the above technical problems, the purpose of the present invention is to provide a lithium battery diaphragm wet line casting roller degreasing device and method, which can absorb the paraffin oil precipitated from the surface of the casting roller to prevent the negative impact of paraffin oil accumulation and reflux on the casting. It can also cooperate with the casting roller to synchronously cool the two surfaces of the casting, thereby achieving rapid and uniform cooling of the casting, which helps to improve the consistency of the thickness of the finished diaphragm product.

[0004] In order to achieve the above-mentioned object, the present invention proposes a lithium battery diaphragm wet casting line roller degreasing device, comprising: a first air nozzle, located on one side of the casting roller, wherein a film-penetrating channel is formed between the first air nozzle and the casting roller to allow the casting to pass through; A second tuyere, located on the other side of the casting roller, wherein the second tuyere and the first tuyere both have an air inlet cavity and an air outlet cavity; a gas-liquid separator, connected to the exhaust cavity pipeline of the second tuyere, and a gas conveying device is provided on the pipeline between the gas-liquid separator and the second tuyere; The condenser has an air inlet connected to the air outlet pipeline of the gas-liquid separator, an air outlet connected to the air inlet cavity pipeline of the first air nozzle, and an exhaust cavity of the first air nozzle connected to the air inlet cavity pipeline of the second air nozzle.

[0005] In some embodiments, the air outlet direction of the first tuyere air inlet cavity is directed along the tangential direction of the casting roller.

[0006] In some embodiments, the air inlet direction of the second tuyere exhaust cavity is directed along the radial direction of the casting roller.

[0007] In some embodiments, the air outlet of the first nozzle is in the shape of a narrow slit.

[0008] In some embodiments, at least two adsorption / desorption chambers are further included, wherein an adsorbent is provided in the adsorption / desorption chambers, and the adsorption / desorption chambers are arranged on the pipe between the condenser and the first air nozzle.

[0009] In some embodiments, the adsorption / desorption chamber is further connected to the gas-liquid separator via a pipeline, and a gas delivery device is provided on the pipeline between the adsorption / desorption chamber and the gas-liquid separator.

[0010] In some embodiments, the material of the adsorbent is selected from one or more of activated carbon and zeolite.

[0011] In some embodiments, the liquid outlets of the gas-liquid separator and the condenser are both connected to a temporary storage tank through pipes, and a filter is provided on the pipe between the gas-liquid separator and the temporary storage tank.

[0012] In some embodiments, the first tuyere is connected to a driving mechanism and is driven by the driving mechanism to move closer to or away from the casting roller.

[0013] The present invention also proposes a method for degreasing a lithium battery diaphragm wet casting roller, the casting method comprising the following steps: The high-temperature melt extruded from the die is rapidly cooled to below the glass transition temperature by the casting roller, so that the melt is transformed from a viscous flow state to an amorphous solid casting sheet; The paraffin oil on the surface of the casting roller is sucked through the exhaust chamber of the second air nozzle, and after the paraffin oil forms oil mist, it is sent to the gas-liquid separator. Most of the oil mist is separated from the air by the gas-liquid separator, and the residual oil mist in the air is recovered by the condenser. At the same time, the air is cooled. The cooled air flows to the first air nozzle to blow the surface of the casting, and then the air flows through the exhaust chamber of the first air nozzle to the air inlet chamber of the second air nozzle, thereby realizing the suction and exhaust cycle.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The lithium battery diaphragm wet-line casting roller degreasing device and method proposed in the present invention constructs a closed system through three-stage treatment of gas-liquid separation, condensation purification and gas circulation, producing a synergistic effect, that is, oil removal, gas purification and auxiliary cooling are completed simultaneously. The treated gas cannot be directly discharged into the air, which can reduce the pollution of oil mist to the environment. At the same time, gas recycling is realized, and energy consumption is reduced. In addition, dry cold air can synchronously assist the shaping of the casting, realize rapid and uniform cooling of the casting, and help to improve the consistency of the thickness of the finished diaphragm product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The preferred embodiments 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 structural schematic diagram of a lithium battery diaphragm wet casting line roller degreasing device according to one embodiment of the present invention.

[0017] Description of Figure Numbers: Die head 1; casting roller 2; first tuyere 3; first gas delivery device 4; gas-liquid separator 5; condenser 6; adsorption / desorption chamber 7; second gas delivery device 8; temporary storage tank 9; casting slab 10; second tuyere 11. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other embodiments can be obtained based on these drawings without inventive work.

[0019] Please refer to Figure 1 , a lithium battery diaphragm wet line casting system according to an embodiment of the present invention includes a casting roller 2 and an oil removal device. The oil removal device can not only absorb the paraffin oil precipitated from the surface of the casting roller 2, but also cool the casting 10. In this embodiment, the casting roller 2 and the oil removal device can cooperate with each other to cool the front and back of the casting 10, so as to achieve rapid and uniform cooling of the casting 10. The front and back of the casting 10 are two surfaces of the casting 10 that are opposite to each other. As an example, the front of the casting 10 refers to the surface of the casting 10 close to the casting roller 2, and the back of the casting 10 refers to the surface of the casting 10 away from the casting roller 2.

[0020] Casting roller 2 is used to cool the slab 10. It rapidly cools the high-temperature melt extruded from die head 1 to below its glass transition temperature, transforming the melt from a viscous flow into an amorphous solid slab 10 and preventing crystallization from affecting subsequent stretching. A circulating cooling medium, such as water or oil, is contained within casting roller 2. Heat exchange between the cooling medium and casting roller 2 maintains a stable temperature, ensuring efficient cooling of the front surface of slab 10.

[0021] The oil removal device includes a first air nozzle 3 , a gas-liquid separator 5 , a condenser 6 and a second air nozzle 11 .

[0022] The second air nozzle 11 is located on one side of the casting roller 2, and the first air nozzle 3 is located on the other side of the casting roller 2. The second air nozzle 11 is positioned close to the casting roller 2 and is used to absorb most of the paraffin oil precipitated from the roller surface of the casting roller 2 and then feed it into the gas-liquid separator 5. The first air nozzle 3 is used to air-cool the back side of the casting slab 10, thereby reducing the temperature of the back side of the casting slab 10. In this embodiment, the second air nozzle 11 is used to degrease the surface of the casting roller 2 to prevent the accumulation and backflow of paraffin oil from affecting the casting slab. The first air nozzle 3 cooperates with the casting roller 2 to simultaneously cool both surfaces of the casting slab 10, achieving rapid and uniform cooling of the casting slab 10, thereby improving the thickness consistency of the finished diaphragm.

[0023] In this embodiment, a membrane-penetrating channel for the casting sheet 10 to pass through is formed in the gap between the first air nozzle 3 and the casting roller 2. The depth of the membrane-penetrating channel is greater than the thickness of the casting sheet 10, so that the casting sheet 10 can pass through the membrane-penetrating channel without contacting the first air nozzle 3, thereby avoiding the first air nozzle 3 scratching the casting sheet 10 due to the relative movement between the casting sheet 10 and the first air nozzle 3, which helps to keep the membrane surface of the casting sheet 10 intact.

[0024] In this embodiment, both the second tuyere 11 and the first tuyere 3 are configured to not only exhaust air but also inhale it. Specifically, both tuyere 11 and the first tuyere 3 have an inlet cavity and an outlet cavity. In this embodiment, the outlet of the inlet cavity of the first tuyere 3 is a narrow slit extending axially along the casting roll 2. The length of the outlet of the inlet cavity is comparable to the axial dimension of the casting roll 2. It should be understood that the slit-like shape described in this embodiment of the present invention refers to a relatively narrow, elongated hole.

[0025] The exhaust cavity of the second air nozzle 11 can be used to evacuate air from the surface of the casting roller 2 to reduce the paraffin oil content on the surface of the casting roller 2. The air intake direction of the exhaust cavity of the second air nozzle 11 is preferably directed along the radial direction of the casting roller 2. This can absorb the paraffin oil on the surface of the casting roller 2 to the greatest extent possible, reducing the workload of subsequent oil scraping and preventing paraffin oil from dripping from the casting roller 2, thereby helping to keep the floor near the casting roller 2 clean.

[0026] During use of the second tuyere 11, negative pressure is applied to the second tuyere 11 by the first gas delivery device 4. Due to the pressure differential, the paraffin oil on the surface of the casting roller 2 forms an oil mist. The oil mist and air then move toward the exhaust chamber of the second tuyere 11, passing through the exhaust chamber and entering the gas-liquid separator 5 via a pipe. The gas-liquid separator 5 separates most of the oil mist from the air. A small portion of the oil mist and air, after leaving the gas-liquid separator 5, undergoes cooling and / or further gas-liquid separation before entering the first tuyere 3. The air is then blown across the surface of the casting 10 from the outlet of the first tuyere 3's inlet chamber.

[0027] Low-temperature air can be blown toward the surface of the slab 10 through the air inlet cavity of the first tuyere 3 to cool the slab 10. The air outlet direction of the air inlet cavity of the first tuyere 3 is preferably tangential to the slab roller 2. This reduces the impact on the surface of the slab 10 while allowing the air to flow along the surface of the slab 10. The air exchanges sufficient heat with the slab 10 during the flow, thereby improving the cooling efficiency of the slab 10.

[0028] The air inlet cavity of the second air nozzle 11 and the air exhaust cavity of the first air nozzle 3 are connected via a duct 110 . In the duct 110 , the exhaust gas of the first air nozzle 3 flows from the first air nozzle 3 side to the second air nozzle 11 side.

[0029] In this embodiment, a membrane-penetrating channel is formed between the casting roller 2 and the first air nozzle 3 to allow the casting 10 to pass through. In order to ensure the cooling effect of the first air nozzle 3 on the casting 10, the first air nozzle 3 needs to be close enough to the casting 10, that is, the depth of the membrane-penetrating channel is slightly greater than the thickness of the casting 10. Since the specifications of the diaphragm produced by the diaphragm wet process line can be adjusted, that is, when the thickness of the finished diaphragm changes, the thickness of the casting 10 needs to be reset, so the gap between the first air nozzle 3 and the casting roller 2 should be adjustable. Based on this, in this embodiment, the first air nozzle 3 is connected to the driving mechanism, and is driven by the driving mechanism to move closer to or away from the casting roller 2. The movement of the first air nozzle 3 can be linear motion, swinging, or other forms of motion, which are not limited in this embodiment. As an example, the driving mechanism can drive the first air nozzle 3 to perform linear motion, and the driving mechanism can adopt a power device such as a cylinder or a hydraulic cylinder.

[0030] The air outlet of the exhaust chamber of the second air nozzle 11 is connected to the pipe 101. The pipe 101 and the pipe 102 are pipes that connect the air outlet of the exhaust chamber of the second air nozzle 11 and the air inlet of the gas-liquid separator 5 via the first gas conveying device 4. The air containing oil mist flows from the side of the second air nozzle 11 to the side of the gas-liquid separator 5 through the first gas conveying device 4 via the pipe 101 and the pipe 102.

[0031] The gas-liquid separator 5 is a device for separating oil mist from air. The structure of the gas-liquid separator 5 is not limited in this embodiment. As an example, the gas-liquid separator 5 can be a cyclone separator. The main features of the cyclone separator are simple structure, great operational flexibility, and high efficiency. It is a novel, efficient, energy-saving, long-term operation and economical separation device. The working principle is to rely on the rotational motion caused by the tangential introduction of airflow and the density difference between the gas and liquid phases. The centrifugal force generated by the high-speed rotation of the fluid in the cyclone separator causes the denser liquid to gradually move downward and eventually be discharged through the liquid outlet of the cyclone separator, while the less dense air is forced upward and eventually discharged through the gas outlet of the cyclone separator.

[0032] Unmelted polymer particles may remain on the surface of the casting roller 2. When the exhaust chamber of the second tuyere 11 is evacuated, these particles are drawn into the cyclone separator and discharged through the liquid outlet at the bottom of the cyclone separator. To prevent particles from entering the temporary storage tank 9, a filter can be installed downstream of the cyclone separator's liquid outlet to separate the particles. To ensure filtering performance, the filter should be cleaned or replaced regularly.

[0033] In this embodiment, after the first gas delivery device 4 is activated, it draws air from the second tuyere 11, creating a negative pressure within the second tuyere 11. Influenced by atmospheric pressure, the second tuyere 11 generates suction on the surface of the casting roller 2. Air and the paraffin oil on the surface of the casting roller 2 enter the exhaust chamber and are forcibly transported to the gas-liquid separator 5. After gas-liquid separation in the gas-liquid separator 5, a small portion of the oil mist and air flows to the condenser 6.

[0034] Condenser 6 is a device that cools the oil mist and air transported through gas-liquid separator 5. Connected to condenser 6 is a pipe 103, which connects the air outlet of gas-liquid separator 5 and the air inlet of condenser 6. In pipe 103, air containing oil mist flows from gas-liquid separator 5 to condenser 6. Condenser 6 includes a cooler disposed in a sealed chamber. The cooler can be a heat exchanger with fins that cools the air and oil mist using a circulating coolant or cooling water as the cooling medium. It is understood that the cooler can also be an electronic cooler equipped with a Peltier element, for example. Within condenser 6, some of the oil mist condenses and collects on the cooler, where it is recovered.

[0035] The bottoms of the gas-liquid separator 5 and condenser 6 are connected to pipes 108 and 109, respectively. Pipe 108 connects the liquid outlet of the gas-liquid separator 5 with the liquid inlet of the temporary storage tank 9. In pipe 108, paraffin oil flows from the gas-liquid separator 5 to the temporary storage tank 9. Pipe 109 connects the liquid outlet of the condenser 6 to the liquid inlet of the temporary storage tank 9. In pipe 109, paraffin oil flows from the condenser 6 to the temporary storage tank 9. The temporary storage tank 9 is a tank for collecting paraffin oil.

[0036] The condenser 6 may also be connected to a pipe 104 , which is a pipe connecting the condenser 6 and the adsorption / desorption device. In the pipe 104 , the oil mist flows from the condenser 6 side to the adsorption / desorption device side.

[0037] In this embodiment, the condenser 6 can lower the temperature of the air after heat exchange, so that the air blown onto the surface of the slab 10 is always maintained within a relatively low temperature range, thereby ensuring a cooling effect on the back of the slab 10. At the same time, the temperature of the air containing the oil mist flowing to the adsorption and desorption device is relatively low. In a low-temperature environment, the kinetic energy of the oil mist molecules is reduced, making them more easily captured by the micropores on the surface of the adsorbent in the desorption tank, thereby improving the adsorption efficiency of the adsorbent.

[0038] The adsorption / desorption device is used to absorb oil mist from the air and desorb previously adsorbed oil mist. The device includes at least two adsorption / desorption chambers 7, each containing an adsorbent for adsorbing oil mist from the air. The present invention does not impose any specific restrictions on the material of the adsorbent; as long as it can adsorb oil mist without chemically reacting with it and can also desorb oil mist after heating, it is sufficient. For example, the adsorbent material can be selected from activated carbon, zeolite, and the like. One or more of these materials can be used.

[0039] The adsorption / desorption chamber 7 is connected to a pipe 105 and a pipe 106. The pipe 105 is a pipe connecting the air outlet of the adsorption / desorption chamber 7 and the air inlet cavity of the first air nozzle 3. In the pipe 105, air flows from the side of the adsorption / desorption chamber 7 to the side of the first air nozzle 3. It can be understood that the condenser 6 can also be directly connected to the air inlet cavity pipeline of the first air nozzle 3 through a pipe. The pipe 106 and the pipe 107 are pipes connecting the adsorption / desorption chamber 7 and the gas-liquid separator 5 via the second gas conveying device 8. In the pipe 106 and the pipe 107, the desorbed oil mist flows from the side of the adsorption / desorption chamber 7 to the side of the gas-liquid separator 5 for secondary recovery. It can be understood that while one of the adsorption / desorption chambers 7 is undergoing adsorption treatment, the adsorbent in the other adsorption / desorption chamber 7 can be desorbed. After a specified period of time, continuous adsorption of the oil mist can be achieved by alternating adsorption and desorption treatments.

[0040] The following specifically introduces the degreasing method of the lithium battery separator wet casting roller, which includes the following steps: The high-temperature melt extruded from the die head 1 is rapidly cooled to below the glass transition temperature by the casting roller 2, so that the melt is transformed from a viscous flow state to an amorphous solid casting sheet; The paraffin oil on the surface of the casting roller 2 is sucked through the exhaust chamber of the second air nozzle 11, and is sent to the gas-liquid separator 5 after the paraffin oil forms oil mist. Most of the oil mist is separated from the air by the gas-liquid separator 5, and the residual oil mist in the air is recovered by the condenser 6. At the same time, the air is cooled, and the cooled air flows to the first air nozzle 3, and the surface of the casting is blown through the air outlet of the air inlet chamber of the first air nozzle 3 to reduce the surface temperature of the casting on the side away from the casting roller 2. The air then flows through the exhaust chamber of the first air nozzle 3 to the air inlet chamber of the second air nozzle 11, thereby realizing the suction and exhaust cycle.

[0041] In summary, the lithium battery diaphragm wet-line casting roller degreasing device proposed in this embodiment, on the one hand, absorbs most of the paraffin oil precipitated from the surface of the casting roller 2 through the second air nozzle 11, preventing the accumulation of paraffin oil and affecting the cooling effect of the casting. At the same time, the first air nozzle 3 and the casting roller 2 respectively cool the two surfaces of the casting 10 synchronously, thereby achieving rapid and uniform cooling of the casting 10, which helps to improve the consistency of the thickness of the finished diaphragm. On the other hand, while the oil mist is separated by the condenser 6, the air flowing into the exhaust chamber of the first air nozzle 3 is cooled. The cooling can cause the oil mist in the air to condense and condense, thereby achieving effective recovery of the oil mist, and can also keep the temperature of the air blown to the casting within a low range, ensuring the cooling efficiency and cooling effect of the casting. On the other hand, the closed-loop design of the gas circulation path realizes the reuse of gas, prevents environmental pollution caused by the escape of oil mist into the factory, and reduces energy consumption.

[0042] 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 noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A lithium battery diaphragm wet casting line roller degreasing device, characterized in that: include: A first air nozzle is located on one side of the casting roller, and a film-penetrating channel is formed between the first air nozzle and the casting roller to allow the casting to pass through; A second tuyere is located on the other side of the casting roller, wherein the second tuyere and the first tuyere both have an air inlet cavity and an air outlet cavity; a gas-liquid separator, connected to the exhaust cavity pipeline of the second tuyere, and a gas conveying device is provided on the pipeline between the gas-liquid separator and the second tuyere; The condenser has an air inlet connected to the air outlet pipeline of the gas-liquid separator, an air outlet connected to the air inlet cavity pipeline of the first air nozzle, and an exhaust cavity of the first air nozzle connected to the air inlet cavity pipeline of the second air nozzle.

2. The lithium battery diaphragm wet casting line roller degreasing device according to claim 1, characterized in that: The air outlet direction of the air inlet cavity of the first air nozzle is along the tangential direction of the casting roller.

3. The lithium battery diaphragm wet casting line roller degreasing device according to claim 1, characterized in that: The air inlet direction of the exhaust cavity of the second tuyere is directed along the radial direction of the casting roller.

4. The lithium battery diaphragm wet casting line roller degreasing device according to claim 1, characterized in that: The air outlet of the air inlet cavity of the first air nozzle is slit-shaped.

5. The lithium battery diaphragm wet casting line roller degreasing device according to claim 1, characterized in that: It also includes at least two adsorption and desorption chambers, wherein adsorbent is provided in the adsorption and desorption chambers, and the adsorption and desorption chambers are arranged on the pipeline between the condenser and the first air nozzle.

6. The lithium battery diaphragm wet casting line roller degreasing device according to claim 5, characterized in that: The adsorption / desorption chamber is also connected to the gas-liquid separator through a pipeline, and a gas conveying device is provided on the pipeline between the adsorption / desorption chamber and the gas-liquid separator.

7. The lithium battery separator wet casting line roll degreasing device according to claim 5, characterized in that: The material of the adsorbent is selected from one or both of activated carbon and zeolite.

8. The lithium battery separator wet casting line roll degreasing device according to claim 1, characterized in that: The liquid outlets of the gas-liquid separator and the condenser are both connected to the temporary storage tank through pipelines, and a filter is provided on the pipeline between the gas-liquid separator and the temporary storage tank.

9. The lithium battery diaphragm wet casting line roller degreasing device according to claim 1, characterized in that: The first tuyere is connected to a driving mechanism and is driven by the driving mechanism to move closer to or away from the casting roller.

10. A method for degreasing a lithium battery separator wet casting roller, characterized in that: The oil removal device according to any one of claims 1 to 9 is used, and the oil removal method comprises the following steps: The high-temperature melt extruded from the die is rapidly cooled to below the glass transition temperature by the casting roller, so that the melt is transformed from a viscous flow state to an amorphous solid casting sheet; The paraffin oil on the surface of the casting roller is sucked through the exhaust chamber of the second air nozzle, and after the paraffin oil forms oil mist, it is sent to the gas-liquid separator. Most of the oil mist is separated from the air by the gas-liquid separator, and the residual oil mist in the air is recovered by the condenser. At the same time, the air is cooled. The cooled air flows to the air inlet chamber of the first air nozzle to blow the casting surface. The air then flows through the exhaust chamber of the first air nozzle to the air inlet chamber of the second air nozzle, thereby realizing the suction and exhaust cycle.

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