Diaphragm slurry coating method based on continuous defoaming

Abstract

The invention discloses a diaphragm slurry coating method based on continuous defoaming, which comprises the following steps: step A, slurry flows into the inner side of a liquid storage tank, and a stirring mechanism on the inner side of the liquid storage tank stirs and mixes the slurry; b, sucking the slurry into a circulating pump after passing through an impurity removal mechanism, and conveying the slurry to one end of a tubular reactor through the circulating pump; c, mixing the slurry through a left spiral piece and a right spiral piece on the inner side of the tubular reactor, breaking bubbles, and enabling the slurry to flow out from the other end of the tubular reactor; during coating, slurry in a slurry liquid storage tank with a stirring mechanism is pumped from one end of a static mixing tubular reactor by a circulating pump, bubbles are separated, crushed and combined on the inner side of the tubular reactor through spirals, and the bubbles in the slurry are conveniently removed, so that continuous defoaming coating work is realized; the method is easy to operate, and industrial continuous production operation is guaranteed.

Description

Technical Field

[0001] The present invention specifically relates to a method for membrane coating slurry based on continuous defoaming. Background Art

[0002] With the rapid development of electric vehicles, electric vehicles have driven the rapid development of the diaphragm industry. Due to the poor heat resistance and poor adhesion of the diaphragm to the battery pole piece, a layer of ceramic and glue is usually coated on the surface of the diaphragm to improve the high temperature resistance and adhesion of the diaphragm. In order to coat the diaphragm with the required thickness and adhesion, the research and production of the performance of ceramic diaphragms and glue-coated diaphragm slurries are particularly important. During the research and production of ceramic slurries and glue-coated slurries, there are often a large number of bubbles in the slurry, especially during nano-grinding and gravure anilox roller coating, which is very easy to generate bubbles, which brings great trouble to the diaphragm coating work.

[0003] Existing defoaming methods are divided into chemical defoaming and physical defoaming: chemical defoaming is to add defoaming agents during the preparation of the slurry. The defoaming agents form a double-layer film on the foam wall. During the diffusion process, the surfactants with stabilizing effects are displaced, thereby reducing the tension of the local surface of the foam and causing the foam to burst. However, since the defoaming agent may react with the compounds in the slurry or affect the slurry properties, the amount added should not be too much, so the defoaming effect is limited;

[0004] Physical defoaming is mainly divided into stirring, vacuum and vibration defoaming. Stirring defoaming uses stirring equipment to fully stir the slurry to remove bubbles from the slurry. This prevention is suitable for more viscous slurries, but may introduce new bubbles; vacuum defoaming is to place the slurry in a vacuum container, and reduce the internal pressure of the container by reducing pressure, so as to release bubbles from the slurry. This method has high requirements on equipment and is more complicated to operate; vibration defoaming separates bubbles from the slurry through vibration. This slurry is suitable for slurry with good fluidity, but has high requirements on equipment; and the above-mentioned physical defoaming methods are not suitable for continuous production. For this reason, we propose a method of diaphragm coating slurry based on continuous defoaming. Summary of the invention

[0005] The purpose of the present invention is to provide a method for diaphragm coating slurry based on continuous defoaming, so as to solve the problems proposed in the above background technology that the existing chemical defoaming requires the addition of a defoaming agent, the defoaming agent will affect the performance of the slurry, the physical stirring defoaming requires the use of viscous slurry, and new bubbles will be introduced, the equipment required for vacuum degassing is too high, the vibration degassing requires the use of slurry with good fluidity and high equipment requirements, and the above degassing method is not suitable for continuous production.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for coating slurry of a diaphragm based on continuous defoaming, comprising the following steps:

[0007] Step A: The slurry flows into the inner side of the liquid storage tank, and the stirring mechanism inside the liquid storage tank stirs and mixes the slurry;

[0008] Step B: The slurry is sucked into the circulation pump after passing through the impurity removal mechanism, and is transported to one end of the tubular reactor through the circulation pump;

[0009] Step C: The slurry is mixed by the left and right spiral parts inside the tubular reactor, the bubbles are broken, and the slurry flows out from the other end of the tubular reactor;

[0010] Step D: The slurry flows from the middle of the coating tank into the interior of the coating tank, and the coating mechanism inside the coating tank coats the slurry onto the diaphragm;

[0011] Step E: Part of the slurry flowing to both ends of the coating tank flows back to the inner side of the storage tank in step A through the pipeline.

[0012] During coating, the slurry in the liquid storage tank with a stirring device is pumped into one end of the static mixing tubular reactor by a circulation pump, passes through the left and right spiral components of the static mixing tubular reactor, and flows out from the other end of the static mixing tubular reactor, thereby eliminating bubbles, and then enters the coating tank from the middle part of the coating tank, and performs continuous coating operations through the coating mechanism.

[0013] Preferably, in step A, the flow viscosity of the slurry is ≤4000 mPa.s.

[0014] It is convenient to make the slurry more evenly distributed and form a coating with consistent thickness.

[0015] Preferably, in step B, the circulating pump is one of a centrifugal pump, a diaphragm pump and a screw pump, and the pressure at which the circulating pump pumps the slurry into the tubular reactor is 0.1 to 0.3 MPa.

[0016] It is convenient to make the slurry flow faster.

[0017] Preferably, in step B, the slurry is transported to the inner side of the tubular reactor for 0.1 to 0.3 m. 3 Pressure bag to achieve uniform feeding rate.

[0018] It is convenient for the slurry to move at a uniform speed, so as to ensure the uniform thickness during the later coating.

[0019] Preferably, in step B, the slurry is firstly subjected to a first impurity removal by a demagnetizer, and then subjected to a second impurity removal by a filter.

[0020] It is convenient to remove impurities in the slurry to ensure the cleanliness of the slurry.

[0021] Preferably, in step C, a plurality of left-handed spiral components and a plurality of right-handed spiral components are provided, and the left-handed spiral components and the right-handed spiral components are alternately arranged in a straight line.

[0022] It is convenient to better split and merge through spiral assembly.

[0023] Preferably, in the step D, the slurry is coated onto the diaphragm in the coating tank by the cooperation of an anilox roller and a resin scraper.

[0024] It is convenient for continuous coating operation.

[0025] Preferably, during coating in step D, the inner side of the coating tank is filled with slurry, the anilox roller rotates clockwise above the coating tank to adhere to the slurry, the resin scraper fits tightly with the anilox roller, scrapes off excess slurry on the anilox roller and returns to the coating tank.

[0026] It is convenient to make the slurry flow back for re-mixing and reuse the slurry.

[0027] Preferably, in step D, the number of mesh lines and the groove depth of the anilox roller are changed with the thickness of the coating membrane.

[0028] It is convenient to adjust the anilox roller according to the thickness of the diaphragm to achieve better coating effect.

[0029] Preferably, in step D, the resin scraper is made of PET material, and the blade angle is 13-30°.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention uses a circulating pump to pump the slurry in a slurry storage tank with a stirring mechanism into one end of a static mixing tubular reactor during coating, and separates, breaks and merges bubbles on the inner side of the tubular reactor through a spiral, so as to facilitate the removal of bubbles in the slurry, thereby achieving continuous defoaming coating and reducing the influence of bubbles on coating. The method is easy to operate and ensures industrial continuous production operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic cross-sectional structure diagram of a tubular mixer of the present invention;

[0033] Figure 2 It is a schematic diagram of the structure of the right spiral member of the present invention;

[0034] Figure 3 It is a schematic diagram of the structure of the left-hand spiral member of the present invention;

[0035] Figure 4 It is a mixing schematic diagram of a tubular mixer of the present invention;

[0036] Figure 5 It is a schematic diagram of slurry diversion of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] See also Figure 1-Figure 5 The present invention provides a technical solution: a method for coating a diaphragm slurry based on continuous defoaming, comprising the following steps:

[0040] Step A: The slurry flows into the inner side of the liquid storage tank, and the stirring mechanism inside the liquid storage tank stirs and mixes the slurry;

[0041] Step B: The slurry is sucked into the circulation pump after passing through the impurity removal mechanism, and is transported to one end of the tubular reactor through the circulation pump;

[0042] Step C: The slurry is mixed by the left and right spiral parts inside the tubular reactor, the bubbles are broken, and the slurry flows out from the other end of the tubular reactor;

[0043] Step D: The slurry flows from the middle of the coating tank into the interior of the coating tank, and the coating mechanism inside the coating tank coats the slurry onto the diaphragm;

[0044] Step E: Part of the slurry flowing to both ends of the coating tank flows back to the inner side of the storage tank in step A through the pipeline.

[0045] During coating, the slurry in the liquid storage tank with a stirring device is pumped into one end of the static mixing tubular reactor by a circulation pump, passes through the left and right spiral components of the static mixing tubular reactor, and flows out from the other end of the static mixing tubular reactor, thereby eliminating bubbles, and then enters the coating tank from the middle part of the coating tank, and performs continuous coating operations through the coating mechanism.

[0046] Preferably, in step A, the flow viscosity of the slurry is ≤4000 mPa.s.

[0047] It is convenient to make the slurry more evenly distributed and form a coating with consistent thickness.

[0048] Preferably, in step B, the circulating pump is one of a centrifugal pump, a diaphragm pump and a screw pump, and the pressure at which the circulating pump pumps the slurry into the tubular reactor is 0.1 to 0.3 MPa.

[0049] It is convenient to make the slurry flow faster.

[0050] Preferably, in step B, the slurry is transported to the inner side of the tubular reactor for 0.1 to 0.3 m. 3 Pressure bag to achieve uniform feeding rate.

[0051] It is convenient for the slurry to move at a uniform speed, so as to ensure the uniform thickness during the later coating.

[0052] Preferably, in step B, the slurry is firstly subjected to a first impurity removal by a demagnetizer, and then subjected to a second impurity removal by a filter.

[0053] It is convenient to remove impurities in the slurry to ensure the cleanliness of the slurry.

[0054] Preferably, in step C, a plurality of left-handed spiral components and a plurality of right-handed spiral components are provided, and the left-handed spiral components and the right-handed spiral components are alternately arranged in a straight line.

[0055] It is convenient to better divide and merge the slurry through the spiral component.

[0056] Preferably, in the step D, the slurry is coated onto the diaphragm in the coating tank by the cooperation of an anilox roller and a resin scraper.

[0057] It is convenient for continuous coating operation.

[0058] Preferably, during coating in step D, the inner side of the coating tank is filled with slurry, the anilox roller rotates clockwise above the coating tank to adhere to the slurry, the resin scraper fits tightly with the anilox roller, scrapes off excess slurry on the anilox roller and returns to the coating tank.

[0059] It is convenient to make the slurry flow back for re-mixing and reuse the slurry.

[0060] It is convenient to adjust the anilox roller according to the thickness of the diaphragm to achieve better coating effect.

[0061] Preferably, in step D, the number of mesh lines and the groove depth of the anilox roller are changed with the thickness of the coating membrane.

[0062] Preferably, in step D, the resin scraper is made of PET material, and the blade angle is 13-30°.

[0063] Example 2

[0064] See also Figure 1-Figure 5 The slurry to be coated is quickly stirred in a slurry storage tank with a stirring mechanism. The slurry viscosity is 15mPa.s. The slurry is sucked into the diaphragm pump through the demagnetizer and filter screen and passes through 0.2m 3After entering the buffer tank, it enters from one end of the tubular reactor, passes through 100 spiral components in the tubular reactor, flows out from the other end of the tubular reactor, and enters the inner side of the coating tank from the middle part of the coating tank. The slurry is coated on the diaphragm with the cooperation of a 180LPI anilox roller with a groove depth of 45μm and a blade angle of 20° and a resin scraper. Part of the slurry flows back to the liquid storage tank with a stirring mechanism through both ends of the coating tank. The slurry flowing back to the liquid storage tank is stirred and then pumped into the coating tank by a circulation pump through the tubular reactor again to participate in coating.

[0065] The parameters of the number of lines and the groove depth of the anilox roller of the present invention are shown in the table below according to the change of the coating thickness of the coated diaphragm:

[0066] Coating thickness μm Network line number LPI Groove depth μm 1 180 45 2 150 65 3 125 80 4 100 90

[0067] In the static mixing tubular reactor of the present invention, the slurry enters the reactor along the pipeline and passes through a special channel composed of a group of left and right spiral elements arranged alternately. The number of left and right spiral elements is determined according to the viscosity of the slurry. The lower the viscosity, the greater the number. After multiple tests and verifications, the relationship between viscosity and the number of left and right spiral elements is obtained. See the table below for details:

[0068]

[0069]

[0070] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for coating a diaphragm slurry based on continuous defoaming, characterized in that: The steps include: Step A: The slurry flows into the inner side of the liquid storage tank, and the stirring mechanism inside the liquid storage tank stirs and mixes the slurry; Step B: The slurry is sucked into the circulation pump after passing through the impurity removal mechanism, and is transported to one end of the tubular reactor through the circulation pump; Step C: The slurry is mixed by the left and right spiral parts inside the tubular reactor, the bubbles are broken, and the slurry flows out from the other end of the tubular reactor; Step D: The slurry flows from the middle of the coating tank into the interior of the coating tank, and the coating mechanism inside the coating tank coats the slurry onto the diaphragm; Step E: Part of the slurry flowing to both ends of the coating tank flows back to the inner side of the storage tank in step A through the pipeline.

2. A method for coating a diaphragm slurry based on continuous defoaming according to claim 1, characterized in that: In the step A, the flow viscosity of the slurry is ≤4000 mPa.s.

3. A method for coating a diaphragm slurry based on continuous defoaming according to claim 1, characterized in that: In the step B, the circulating pump is one of a centrifugal pump, a diaphragm pump and a screw pump, and the pressure at which the circulating pump pumps the slurry into the tubular reactor is 0.1-0.3 MPa.

4. A method for coating a diaphragm slurry based on continuous defoaming according to claim 1, characterized in that: In the step B, the slurry is transported to the inner side of the tubular reactor through 0.1 to 0.3 m 3 Pressure bag to achieve uniform feeding rate.

5. The method for coating slurry of a diaphragm based on continuous defoaming according to claim 1, characterized in that: In the step B, the slurry is firstly subjected to a first impurity removal by a demagnetizer, and then subjected to a second impurity removal by a filter.

6. A method for coating a diaphragm slurry based on continuous defoaming according to claim 1, characterized in that: In the step C, a plurality of left-handed spiral components and a plurality of right-handed spiral components are provided, and the left-handed spiral components and the right-handed spiral components are alternately arranged in a straight line.

7. A method for coating a diaphragm slurry based on continuous defoaming according to claim 1, characterized in that: In the step D, the slurry is coated onto the diaphragm in the coating tank by the cooperation of the anilox roller and the resin scraper.

8. A method for coating a diaphragm slurry based on continuous defoaming according to claim 7, characterized in that: During coating in step D, the inner side of the coating tank is filled with slurry, the anilox roller rotates clockwise above the coating tank to adhere to the slurry, the resin scraper fits tightly with the anilox roller, scrapes off excess slurry on the anilox roller and returns to the coating tank.

9. The method for coating slurry of a diaphragm based on continuous defoaming according to claim 7, characterized in that: In the step D, the number of mesh lines and the groove depth of the anilox roller are changed according to the thickness of the coating membrane.

10. The method for coating slurry of a diaphragm based on continuous defoaming according to claim 7, characterized in that: In the step D, the resin scraper is made of PET material, and the blade angle is 13 to 30 degrees.

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