PVC modified battery membrane and preparation method thereof

Abstract

The invention discloses a preparation method of a PVC (polyvinyl chloride) modified battery membrane, which comprises the following steps: weighing raw materials according to a raw material ratio, and sequentially mixing and stirring the raw materials at a low speed and a high speed; the temperature of the mixed materials is 80-100 DEG C, and the banburying current is 320-360 amperes; primarily plasticizing the internally mixed colloidal raw material at the temperature of 150-160 DEG C to obtain a primarily plasticized material; according to the modified battery membrane, PVC is matched with the heat stabilizer, the internal lubricant, the external lubricant and other raw materials, meanwhile, the added adjusting and connecting agent and filling agent serve as functional auxiliaries, the adjusting and connecting agent and the filling agent are blended, synergic and jointly reinforced, and the prepared battery membrane product is remarkable in voltage resistance and low-temperature toughness performance.

Description

Technical Field

[0001] The present invention relates to the technical field of battery membranes, and in particular to a PVC modified battery membrane and a preparation method thereof. Background Art

[0002] Under the influence of the greenhouse effect brought about by carbon dioxide and the urgent situation of global warming, the new energy industry has been vigorously developed.

[0003] The new energy industry is being driven by the vigorous promotion of electric vehicles, electric motorcycles, and electric bicycles. The core component of electric vehicles is the power battery. Power battery cases are divided into two categories: engineering plastic and aluminum alloy. The aluminum alloy case, with its printed logo and trademark, is wrapped in a PVC polymer film, known as a battery film. Common PVC battery films currently on the market have two issues: 1. Their voltage resistance does not meet standards, posing a safety hazard in the event of battery leakage; 2. Their low-temperature toughness is insufficient, making them prone to cracking when coated on the power battery surface in winter. Based on these issues, the present invention further improves and addresses these issues. Summary of the Invention

[0004] In view of the defects of the prior art, the purpose of the present invention is to provide a PVC modified battery membrane and a preparation method thereof to solve the problems raised in the above background technology.

[0005] The present invention solves the technical problem by adopting the following technical solutions: The present invention provides a PVC modified battery membrane, comprising the following raw materials in parts by weight: PVC7: 70-80 parts; PVC5: 20-30 parts; Heat stabilizer: 2.5-3.5 parts; Internal lubricant: 0.5-1.0 parts; External lubricant: 0.4-0.8 parts; Toughening agent: 10.0-15.0 parts; Processing aid: 1.0-2.0 parts; Colorant: 0.02-0.1 parts.

[0006] Preferably, the PVC7 is a PVC with a degree of polymerization of 800; the PVC5 is a PVC with a degree of polymerization of 1000; The heat stabilizer is liquid mercaptan methyl tin stabilizer; The internal lubricant is fatty acid partial glyceride; The external lubricant is calcium or sodium stearoyl lactylate; The processing aid is methyl acrylate; The toughening agent is nitrile rubber pre-dispersed with DOS (dioctyl sebacate).

[0007] The colorant is one of white, yellow and black.

[0008] Preferably, the battery film further comprises 5-9 parts by weight of a connecting agent and 3-5 parts by weight of a filler; The preparation method of the connecting agent is as follows: S1: Add 3-5 parts of strontium titanate, 1-2 parts of silane coupling agent and 0.5-0.8 parts of silicon carbide to 5-8 parts of sodium alginate solution, stir evenly, and obtain strontium titanate solution; S2: preheating the boron nitride at 60-65°C for 1 hour, immersing the preheated boron nitride in a 5% lanthanum chloride solution with a mass fraction of 3-5 times the total amount of boron nitride, stirring thoroughly, then filtering and drying to obtain a modified boron nitride agent; The modified boron nitride agent and strontium titanate solution were mixed in a weight ratio of 5:3 and ball-milled at a ball-milling speed of 1500 r / min for 2 h. After the ball-milling was completed, the mixture was filtered and dried to obtain a bonding agent.

[0009] Preferably, the silane coupling agent is silane coupling agent KH550; and the mass fraction of the sodium alginate solution is 4-7%.

[0010] Preferably, the preparation method of the filler is: S11: adding 3-5 parts of boehmite, 2-3 parts of sodium carboxymethyl cellulose and 1-3 parts of nano-silica sol to 5-8 parts of calcium zirconate solution and stirring uniformly to obtain a modified solution; S12: irradiating the calcium sulfate whiskers in a proton irradiation box for 1 hour at an irradiation power of 350-400 W, and obtaining irradiated calcium sulfate whiskers after the irradiation is completed; The irradiated calcium sulfate whiskers and the modified liquid were stirred and modified in a weight ratio of 3:5. After the stirring was completed, the mixture was filtered and dried to obtain a filler.

[0011] Preferably, the stirring temperature of the stirring modification treatment is 60-65° C., the stirring speed is 550-750 r / min, and the stirring time is 1 hour.

[0012] Preferably, the preparation method of the calcium zirconate solution is: 4-7 parts of calcium zirconate and 2-4 parts of glass fiber are added to 8-10 parts of dopamine hydrochloride solution, and then 3-5 parts of barium nitrate solution are added and stirred evenly to obtain calcium zirconate solution.

[0013] Preferably, the mass fraction of the dopamine hydrochloride solution is 5-8%; the mass fraction of the barium nitrate solution is 2-5%.

[0014] The present invention also provides a method for preparing a PVC modified battery membrane, comprising the following steps: (1) Weigh all raw materials according to the raw material ratio, and mix them at low speed and high speed in turn; the temperature of the mixed materials is 80-100℃, and the mixing current is 320-360A; the mixed colloidal raw materials are preliminarily plasticized at a preliminarily plasticizing temperature of 150-160℃ to obtain the primary plasticized material; (2) The primary plasticized material is plasticized in an open mill for secondary plasticization and then fed into a single screw extruder for secondary plasticization and filtration. The secondary plasticization temperature is 160-170°C; the screw extrusion filter temperature is 165°C-180°C to obtain a re-plasticized material; (3) The composite material is subjected to 5-roll calendering, and then embossed, cooled and rolled to obtain a battery film.

[0015] Preferably, the low-speed mixing time is 20-50 seconds, and the mixing speed is 50-300 rpm / min; the high-speed mixing time is 150-200 seconds, and the mixing speed is 400-600 rpm / min.

[0016] Preferably, the temperatures of the 5-roll calender are 185°C-190°C for roller 1, 188°C-195°C for roller 2, 190°C-200°C for roller 3, 195°C-210°C for roller 4, and 185°C-190°C for roller 5.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The modified battery membrane of the present invention adopts PVC combined with heat stabilizer, internal lubricant, external lubricant and other raw materials, and at the same time adds a bonding agent and a filler as functional additives. The two are coordinated and reinforced together, and the battery membrane product prepared has significant voltage resistance and low-temperature toughness.

[0018] 2. The strontium titanate in the coupling agent is combined with a silane coupling agent, silicon carbide, and sodium alginate solution for joint performance adjustment. At the same time, the boron nitride is preheated and then improved with a lanthanum chloride solution. The modified boron nitride agent obtained is mixed with the strontium titanate solution. The coupling agent prepared in the system optimizes the performance coordination of the product and improves the corrosion resistance and stability of the product.

[0019] 3. The filler is made of calcium sulfate whiskers that have been irradiated with protons to stimulate their active efficiency, and then stirred with a modifying liquid for modification. The boehmite in the modifying liquid is combined with carboxymethyl cellulose and calcium zirconate liquid to achieve synergistic improvement. At the same time, the calcium zirconate in the calcium zirconate liquid is combined with glass fiber, barium nitrate solution, and dopamine hydrochloride solution. Through the synergistic effect between the raw materials, the filler and the coupling agent are further synergistic, thereby further improving the performance of the product. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. 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 making creative efforts are within the scope of protection of the present invention.

[0021] Example 1. A PVC modified battery membrane of this embodiment includes the following raw materials in parts by weight: PVC7: 70 parts; PVC5: 20 parts; Heat stabilizer: 2.5 parts; Internal lubricant: 0.5 parts; External lubricant: 0.4 parts; Toughening agent: 10.0 parts; Processing aid: 1.0 part; Colorant: 0.02 parts.

[0022] PVC7 is PVC with a degree of polymerization of 800; PVC5 is PVC with a degree of polymerization of 1000; The heat stabilizer is liquid mercaptan methyl tin stabilizer; The internal lubricant is fatty acid partial glyceride; The external lubricant is calcium stearoyl lactylate; The processing aid is methyl acrylate; The toughening agent is nitrile rubber pre-dispersed with DOS (dioctyl sebacate).

[0023] The pigment is white.

[0024] The battery membrane of this embodiment also includes 5 parts by weight of a bonding agent and 3 parts by weight of a filler; The preparation method of the connecting agent is as follows: S1: Add 3 parts of strontium titanate, 1 part of silane coupling agent and 0.5 parts of silicon carbide to 5 parts of sodium alginate solution and stir evenly to obtain strontium titanate solution; S2: preheating the boron nitride at 60°C for 1 hour, immersing the preheated boron nitride in a 5% lanthanum chloride solution with a mass fraction three times the total amount of boron nitride, stirring thoroughly, then filtering and drying to obtain a modified boron nitride agent; The modified boron nitride agent and strontium titanate solution were mixed in a weight ratio of 5:3 and ball-milled at a ball-milling speed of 1500 r / min for 2 h. After the ball-milling was completed, the mixture was filtered and dried to obtain a bonding agent.

[0025] The silane coupling agent in this embodiment is silane coupling agent KH550; the mass fraction of the sodium alginate solution is 4%.

[0026] The preparation method of the filler of this embodiment is: S11: adding 3 parts of boehmite, 2 parts of sodium carboxymethyl cellulose and 1 part of nano-silica sol to 5 parts of calcium zirconate solution and stirring evenly to obtain a modified solution; S12: irradiating the calcium sulfate whiskers in a proton irradiation box for 1 hour at an irradiation power of 350 W, and obtaining irradiated calcium sulfate whiskers after the irradiation is completed; The irradiated calcium sulfate whiskers and the modified liquid were stirred and modified in a weight ratio of 3:5. After the stirring was completed, the mixture was filtered and dried to obtain a filler.

[0027] The stirring temperature of the stirring modification treatment in this embodiment is 60° C., the stirring speed is 550 r / min, and the stirring is carried out for 1 hour.

[0028] The preparation method of the calcium zirconate solution of this embodiment is: 4 parts of calcium zirconate and 2 parts of glass fiber are added to 8 parts of dopamine hydrochloride solution, and then 3 parts of barium nitrate solution are added and stirred evenly to obtain calcium zirconate solution.

[0029] The mass fraction of the dopamine hydrochloride solution in this embodiment is 5%; the mass fraction of the barium nitrate solution is 2%.

[0030] The method for preparing a PVC modified battery membrane of this embodiment includes the following steps: (1) Weigh all raw materials according to their proportions and mix them at low speed and high speed in sequence; set the mixed material temperature to 80°C and the mixing current to 320A; perform preliminary plasticization on the mixed colloidal raw materials at a preliminary plasticizing temperature of 150°C to obtain the primary plasticized material; (2) The primary plasticized material is plasticized twice in an open mill and then fed into a single screw extruder for plasticization again and then filtered. The temperature of the secondary plasticization is 160°C; the temperature of the screw extruder filter is 165°C to obtain a re-plasticized material; (3) The composite material is subjected to 5-roll calendering, and then embossed, cooled and rolled to obtain a battery film.

[0031] In this embodiment, the low-speed mixing time is 20 seconds, and the mixing speed is 50 rpm / min; the high-speed mixing time is 150 seconds, and the mixing speed is 400 rpm / min.

[0032] The temperatures of the 5-roll calender in this embodiment are 185°C for roller No. 1, 188°C for roller No. 2, 190°C for roller No. 3, 195°C for roller No. 4, and 185°C for roller No. 5.

[0033] Example 2. A PVC modified battery membrane of this embodiment includes the following raw materials in parts by weight: PVC7: 80 parts; PVC5: 30 parts; Heat stabilizer: 3.5 parts; Internal lubricant: 1.0 part; External lubricant: 0.8 parts; Toughener: 15.0 parts; Processing aid: 2.0 parts; Colorant: 0.1 parts.

[0034] Preferably, the PVC7 is a PVC with a degree of polymerization of 800; the PVC5 is a PVC with a degree of polymerization of 1000; The heat stabilizer is liquid mercaptan methyl tin stabilizer; The internal lubricant is fatty acid partial glyceride; The external lubricant is sodium stearoyl lactylate; The processing aid is methyl acrylate; The toughening agent is nitrile rubber pre-dispersed with DOS (dioctyl sebacate).

[0035] The pigment is black.

[0036] The battery membrane of this embodiment further includes 9 parts by weight of a bonding agent and 5 parts by weight of a filler; The preparation method of the connecting agent is as follows: S1: Add 5 parts of strontium titanate, 2 parts of silane coupling agent and 0.8 parts of silicon carbide to 8 parts of sodium alginate solution and stir evenly to obtain strontium titanate solution; S2: preheating the boron nitride at 65°C for 1 hour, immersing the preheated boron nitride in a 5% lanthanum chloride solution with a mass fraction of 5 times the total amount of boron nitride, stirring thoroughly, then filtering and drying to obtain a modified boron nitride agent; The modified boron nitride agent and strontium titanate solution were mixed in a weight ratio of 5:3 and ball-milled at a ball-milling speed of 1500 r / min for 2 hours. After the ball-milling was completed, the mixture was filtered and dried to obtain a bonding agent.

[0037] The silane coupling agent in this embodiment is silane coupling agent KH550; the mass fraction of the sodium alginate solution is 7%.

[0038] The preparation method of the filler of this embodiment is: S11: adding 5 parts of boehmite, 3 parts of sodium carboxymethyl cellulose and 3 parts of nano-silica sol to 8 parts of calcium zirconate solution and stirring uniformly to obtain a modified solution; S12: irradiating the calcium sulfate whiskers in a proton irradiation box for 1 hour at an irradiation power of 400 W, and obtaining irradiated calcium sulfate whiskers after the irradiation is completed; The irradiated calcium sulfate whiskers and the modified liquid were stirred and modified in a weight ratio of 3:5. After the stirring was completed, the mixture was filtered and dried to obtain a filler.

[0039] The stirring temperature of the stirring modification treatment in this embodiment is 65° C., the stirring speed is 750 r / min, and the stirring is carried out for 1 hour.

[0040] The preparation method of the calcium zirconate solution of this embodiment is: 7 parts of calcium zirconate and 4 parts of glass fiber are added to 10 parts of dopamine hydrochloride solution, and then 5 parts of barium nitrate solution are added and stirred evenly to obtain calcium zirconate solution.

[0041] The mass fraction of the dopamine hydrochloride solution in this embodiment is 8%; the mass fraction of the barium nitrate solution is 5%.

[0042] The method for preparing a PVC modified battery membrane of this embodiment includes the following steps: (1) Weigh all raw materials according to their proportions, and mix them at low speed and high speed in turn; set the mixed material temperature to 100°C and the mixing current to 360A; perform preliminary plasticization on the mixed colloidal raw materials at a preliminary plasticizing temperature of 160°C to obtain the primary plasticized material; (2) The primary plasticized material is plasticized twice in an open mill and then fed into a single screw extruder for plasticization again and then filtered. The temperature of the secondary plasticization is 170°C; the temperature of the screw extruder filter is 180°C to obtain a re-plasticized material; (3) The composite material is subjected to 5-roll calendering, and then embossed, cooled and rolled to obtain a battery film.

[0043] In this embodiment, the low-speed mixing time is 50 seconds, and the mixing speed is 300 rpm / min; the high-speed mixing time is 200 seconds, and the mixing speed is 600 rpm / min.

[0044] The temperatures of the 5-roll calender in this embodiment are 190°C for roller No. 1, 195°C for roller No. 2, 200°C for roller No. 3, 210°C for roller No. 4, and 190°C for roller No. 5.

[0045] Example 3. A PVC modified battery membrane of this embodiment includes the following raw materials in parts by weight: PVC7: 75 parts; PVC5: 25 parts; Heat stabilizer: 3.0 parts; Internal lubricant: 0.75 parts; External lubricant: 0.6 parts; Toughener: 12.5 parts; Processing aid: 1.5 parts; Colorant: 0.08 parts.

[0046] Preferably, the PVC7 is a PVC with a degree of polymerization of 800; the PVC5 is a PVC with a degree of polymerization of 1000; The heat stabilizer is liquid mercaptan methyl tin stabilizer; The internal lubricant is fatty acid partial glyceride; The external lubricant is calcium or sodium stearoyl lactylate; The processing aid is methyl acrylate; The toughening agent is nitrile rubber pre-dispersed with DOS (dioctyl sebacate).

[0047] The pigment is black.

[0048] The battery membrane of this embodiment further includes 7 parts by weight of a bonding agent and 4 parts by weight of a filler; The preparation method of the connecting agent is as follows: S1: Add 4 parts of strontium titanate, 1.5 parts of silane coupling agent and 0.65 parts of silicon carbide to 6.5 parts of sodium alginate solution and stir evenly to obtain strontium titanate solution; S2: preheating the boron nitride at 62.5°C for 1 hour, immersing the preheated boron nitride in a 5% lanthanum chloride solution with a mass fraction of 4 times the total amount of boron nitride, stirring thoroughly, then filtering and drying to obtain a modified boron nitride agent; The modified boron nitride agent and strontium titanate solution were mixed in a weight ratio of 5:3 and ball-milled at a ball-milling speed of 1500 r / min for 2 h. After the ball-milling was completed, the mixture was filtered and dried to obtain a bonding agent.

[0049] The silane coupling agent in this embodiment is silane coupling agent KH550; the mass fraction of the sodium alginate solution is 5.5%.

[0050] The preparation method of the filler of this embodiment is: S11: adding 4 parts of boehmite, 2.5 parts of sodium carboxymethyl cellulose and 2 parts of nano-silica sol to 6.5 parts of calcium zirconate solution and stirring uniformly to obtain a modified solution; S12: irradiating the calcium sulfate whiskers in a proton irradiation box for 1 hour at an irradiation power of 375 W, and obtaining irradiated calcium sulfate whiskers after the irradiation is completed; The irradiated calcium sulfate whiskers and the modified liquid were stirred and modified in a weight ratio of 3:5. After the stirring was completed, the mixture was filtered and dried to obtain a filler.

[0051] The stirring temperature of the stirring modification treatment in this embodiment is 62.5° C., the stirring speed is 600 r / min, and the stirring is carried out for 1 hour.

[0052] The preparation method of the calcium zirconate solution of this embodiment is: 5.5 parts of calcium zirconate and 3 parts of glass fiber are added to 9 parts of dopamine hydrochloride solution, and then 4 parts of barium nitrate solution are added and stirred evenly to obtain calcium zirconate solution.

[0053] The mass fraction of the dopamine hydrochloride solution in this embodiment is 6.5%; the mass fraction of the barium nitrate solution is 3.5%.

[0054] The method for preparing a PVC modified battery membrane of this embodiment includes the following steps: (1) Weigh all raw materials according to their proportions and mix them at low speed and high speed in turn; set the mixed material temperature to 90°C and the mixing current to 335A; perform preliminary plasticization on the mixed colloidal raw materials at a preliminary plasticizing temperature of 155°C to obtain the primary plasticized material; (2) The primary plasticized material is plasticized twice in an open mill and then fed into a single screw extruder for plasticization again and then filtered. The temperature of the secondary plasticization is 165°C; the temperature of the screw extruder filter is 170°C to obtain a re-plasticized material; (3) The composite material is subjected to 5-roll calendering, and then embossed, cooled and rolled to obtain a battery film.

[0055] In this embodiment, the low-speed mixing time is 35 seconds, and the mixing speed is 200 rpm / min; the high-speed mixing time is 175 seconds, and the mixing speed is 500 rpm / min.

[0056] The temperatures of the 5-roll calender in this embodiment are 188°C for roller No. 1, 192°C for roller No. 2, 195°C for roller No. 3, 205°C for roller No. 4, and 188°C for roller No. 5.

[0057] Comparative Example 1. The difference from Example 3 is that no connecting agent is added.

[0058] Comparative Example 2. The difference from Example 3 is that no modified boron nitride agent is added to the bonding agent.

[0059] Comparative Example 3. The difference from Example 3 is that no strontium titanate solution is added to the bonding agent.

[0060] Comparative Example 4. The difference from Example 3 is that no strontium titanate or silicon carbide is added to the strontium titanate solution.

[0061] Comparative Example 5. The difference from Example 3 is that no filler was added.

[0062] Comparative Example 6. The difference from Example 3 is that no irradiated calcium sulfate whiskers are added to the filler.

[0063] Comparative Example 7. The difference from Example 3 is that no modifying liquid is added to the filler.

[0064] Comparative Example 8. The difference from Example 3 is that boehmite and sodium carboxymethyl cellulose are not added to the modified solution.

[0065] Comparative Example 9. The difference from Example 3 is that no calcium zirconate or glass fiber is added to the calcium zirconate solution.

[0066] The products of Examples 1-4 of the present invention and Comparative Examples 1-9 were subjected to performance tests.

[0067]

[0068] It can be seen from Examples 1-3 and Comparative Examples 1-9 that the product of the present invention has excellent breakdown strength and low-temperature fracture performance, and the corrosion resistance and stability of the product are significant. The combination of the coupling agent and the filler is practical, which has significant advantages in improving the performance of the product. In addition, when the modified boron nitride agent is not added to the coupling agent, the strontium titanate solution is not added to the coupling agent, and strontium titanate and silicon carbide are not added to the strontium titanate solution, the performance of the product tends to deteriorate to varying degrees. The coupling agent obtained by the specific method of the present invention has the most significant performance effect. When no irradiated calcium sulfate whiskers were added to the filler, no modifying liquid was added to the filler, no boehmite and sodium carboxymethyl cellulose were added to the modifying liquid, and no calcium zirconate and glass fiber were added to the calcium zirconate liquid, the performance of the products all showed a trend of deterioration to varying degrees. The irradiated calcium sulfate whiskers improved with the modifying liquid obtained by the specific method of the present invention had the most significant performance effect of the product. The effects of other methods were not as obvious as those of the present invention.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0070] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A PVC modified battery membrane, characterized in that: It includes the following raw materials in parts by weight: PVC7: 70-80 parts; PVC5: 20-30 parts; Heat stabilizer: 2.5-3.5 parts; Internal lubricant: 0.5-1.0 parts; External lubricant: 0.4-0.8 parts; Toughening agent: 10.0-15.0 parts; Processing aid: 1.0-2.0 parts; Colorant: 0.02-0.1 parts.

2. A PVC modified battery membrane according to claim 1, characterized in that: The PVC7 is a PVC with a degree of polymerization of 800; PVC5 is a PVC with a degree of polymerization of 1000; The heat stabilizer is liquid mercaptan methyl tin stabilizer; The internal lubricant is fatty acid partial glyceride; The external lubricant is calcium or sodium stearoyl lactylate; The processing aid is methyl acrylate; The toughening agent is nitrile rubber pre-dispersed with DOS (dioctyl sebacate); The colorant is one of white, yellow and black.

3. A PVC modified battery membrane according to claim 2, characterized in that: The battery film further comprises 5-9 parts by weight of a bonding agent and 3-5 parts by weight of a filler; The preparation method of the connecting agent is as follows: S1: Add 3-5 parts of strontium titanate, 1-2 parts of silane coupling agent and 0.5-0.8 parts of silicon carbide to 5-8 parts of sodium alginate solution, stir evenly, and obtain strontium titanate solution; S2: preheating the boron nitride at 60-65°C for 1 hour, immersing the preheated boron nitride in a 5% lanthanum chloride solution with a mass fraction of 3-5 times the total amount of boron nitride, stirring thoroughly, then filtering and drying to obtain a modified boron nitride agent; The modified boron nitride agent and strontium titanate solution were mixed in a weight ratio of 5:3 and ball-milled at a ball-milling speed of 1500 r / min for 2 h. After the ball-milling was completed, the mixture was filtered and dried to obtain a bonding agent.

4. The PVC modified battery membrane according to claim 2, characterized in that: The silane coupling agent is silane coupling agent KH550; the mass fraction of the sodium alginate solution is 4-7%.

5. The PVC modified battery membrane according to claim 1, characterized in that: The preparation method of the filler is: S11: adding 3-5 parts of boehmite, 2-3 parts of sodium carboxymethyl cellulose and 1-3 parts of nano-silica sol to 5-8 parts of calcium zirconate solution and stirring uniformly to obtain a modified solution; S12: irradiating the calcium sulfate whiskers in a proton irradiation box for 1 hour at an irradiation power of 350-400 W, and obtaining irradiated calcium sulfate whiskers after the irradiation is completed; The irradiated calcium sulfate whiskers and the modified liquid were stirred and modified in a weight ratio of 3:

5. After the stirring was completed, the mixture was filtered and dried to obtain a filler.

6. The PVC modified battery membrane according to claim 4, characterized in that: The stirring temperature of the stirring modification treatment is 60-65° C., the stirring speed is 550-750 r / min, and the stirring is performed for 1 hour.

7. The PVC modified battery membrane according to claim 4, characterized in that: The preparation method of the calcium zirconate solution is: 4-7 parts of calcium zirconate and 2-4 parts of glass fiber are added to 8-10 parts of dopamine hydrochloride solution, and then 3-5 parts of barium nitrate solution are added and stirred evenly to obtain calcium zirconate solution.

8. The PVC modified battery membrane according to claim 6, characterized in that: The mass fraction of the dopamine hydrochloride solution is 5-8%; the mass fraction of the barium nitrate solution is 2-5%.

9. The method for preparing a PVC modified battery membrane according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Weigh all raw materials according to the raw material ratio, and mix them at low speed and high speed in turn; the temperature of the mixed materials is 80-100℃, and the mixing current is 320-360A; the mixed colloidal raw materials are preliminarily plasticized at a preliminarily plasticizing temperature of 150-160℃ to obtain the primary plasticized material; (2) The primary plasticized material is plasticized in an open mill for secondary plasticization and then fed into a single screw extruder for secondary plasticization and filtration. The secondary plasticization temperature is 160-170°C; the screw extrusion filter temperature is 165°C-180°C to obtain a re-plasticized material; (3) The composite material is subjected to 5-roll calendering, and then embossed, cooled and rolled to obtain a battery film.

10. The method for preparing a PVC modified battery membrane according to claim 8, characterized in that: in: The low-speed mixing time is 20-50 seconds, and the mixing speed is 50-300 rpm / min; the high-speed mixing time is 150-200 seconds, and the mixing speed is 400-600 rpm / min.

11. The method for preparing a PVC modified battery membrane according to claim 8, characterized in that: The temperatures of the 5-roll calender are 185℃-190℃ for roller No. 1, 188℃-195℃ for roller No. 2, 190℃-200℃ for roller No. 3, 195℃-210℃ for roller No. 4, and 185℃-190℃ for roller No. 5.

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