Method for preparing heat-resistant liquid-holding lithium battery diaphragm

A lithium battery separator, heat-resistant technology, applied in battery pack parts, circuits, electrical components, etc., can solve the problems of poor wettability, shorten battery life, accelerate lithium-ion battery damage, etc., and achieve the effect of strong heat resistance

Inactive Publication Date: 2019-05-21

江苏奔拓电气科技有限公司

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AI-Extracted Technical Summary

Problems solved by technology

[0005] The technical problem mainly solved by the present invention is that the current lithium-ion battery has been gradually expanded to the field of electric bicycles and electric vehicles, and is developing in the direction of high power and high current. The working temperature of the diaphragm of the lithium-ion battery is also increased, and the diaphragm is easily Under the action of thermal expansion and contraction, the electrical insulation nanoparticles in the coating are peeled off, and the microporous structure of the separator is blocked under the high temperature working environment, which leads to the obstructio...

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Abstract

The invention discloses a method for preparing a heat-resistant liquid-holding lithium battery diaphragm and belongs to the technical field of lithium battery preparation. The battery diaphragm is mainly composed of aluminium oxide and silicon dioxide, the melting points of which are both above 1000 DEG C, the produced heat and the increased temperature are low during battery charging and discharging and the pore structure of the battery diaphragm is not influenced by high temperature expansion, so that the battery diaphragm has strong heat resistance; a shorter channel can be provided for ionconduction and the ion resistance is reduced by utilizing an aluminium oxide membrane with high porosity and a through-pore structure in the lithium battery diaphragm, so that the electrochemical performance is improved; and calcium lignosulfonate and acrylamide are grafted to obtain a graft copolymer and the graft copolymer is modified by dimethylamine and formaldehyde and reacted with N-vinyl pyrrolidone to obtain an amphoteric graft copolymer which can serve as an organic hygroscopic material to improve the wettability of the battery diaphragm to an electrolyte, so that the liquid absorption rate and the liquid-holding rate of a lithium battery are increased; and therefore, the lithium battery diaphragm has a broad application prospect.

Application Domain

Cell component details

Technology Topic

IonAluminium oxide +19

Examples

Experimental program(3)
Comparison scheme(3)
Effect test(1)

Example Embodiment

[0026] Example 1

[0027] Preparation of primary alumina flakes:

[0028] A circular aluminum sheet with a diameter of 16 mm was placed in 100 mL of absolute ethanol for ultrasonic treatment for 8 min, and then the circular aluminum sheet was taken out and placed in 120 mL of 10% sodium hydroxide solution for ultrasonic treatment for 10 min, and the ultrasonic frequency was controlled to 30 kHz. The surface-treated aluminum flakes are obtained, and the surface-treated aluminum flakes are washed three times with deionized water to obtain anode aluminum flakes. The sheet is used as the anode, and the untreated high-purity aluminum sheet is placed in the mixed solution as the cathode, and polished at a voltage of 15V to obtain a polished anode aluminum sheet;

[0029] The graphite rod as the cathode and the above-mentioned polished anode aluminum sheet as the anode were placed in a beaker containing an oxalic acid solution with a mass fraction of 30%, the distance between the positive and negative electrodes of the battery was controlled to be 6 cm, and the beaker was placed on ice at 0 °C. In a water bath, electrolysis was performed at a voltage of 20V for 5h, and the obtained anode was the primary alumina sheet.

[0030] Preparation of base film:

[0031] Mix the phosphoric acid solution with a mass fraction of 6% and a chromic acid solution with a mass fraction of 2% in equal volumes to obtain a mixed acid solution. After the aluminum flakes after primary oxidation are soaked in the mixed acid solution for 6 hours, the primary aluminum oxide flakes are immersed in the mixed acid solution. As the anode, the graphite rod is used as the cathode, and electrolysis is carried out in the oxalic acid solution with a mass fraction of 30% for secondary oxidation, and the electrification voltage is controlled to 25V to obtain secondary alumina sheets. Mixed solution, the secondary alumina sheet is placed in the mixed solution, and the anodic porous alumina film is obtained by peeling off the pulse voltage at a voltage of 45V;

[0032] The anodic porous alumina membrane was placed in a phosphoric acid solution with a mass fraction of 5% for pore expansion for 30 minutes, and 40 g of silica gel powder was put into 100 mL of ammonia water with a mass fraction of 5%, and stirred and mixed for 5 minutes to obtain a silica gel liquid. The anodic porous alumina membrane was immersed in the silica gel solution, heated to 70°C, soaked for 2 hours, placed in a muffle furnace, heated to 1200°C, sintered for 5 hours, naturally cooled to room temperature, and discharged to obtain a base film.

[0033] Preparation of heat-resistant and liquid-retaining lithium battery separator:

[0034] Grind the calcium lignosulfonate solid for 20min to obtain calcium lignosulfonate powder, configure the calcium lignosulfonate powder into a 400mL mass fraction of a 30% calcium lignosulfonate aqueous solution, and add it to a three-necked flask with a stirrer and a dropping funnel , after passing nitrogen to the three-necked flask to remove the air, adding a potassium hydroxide solution with a mass fraction of 40% to the three-necked flask to adjust the pH to 8, and stirring for 10min to obtain an alkalizing solution;

[0035] Add 80g acrylamide to the above-mentioned three-necked flask, start the stirrer, stir with a rotating speed of 300r/min, place the base film at the bottom of the three-necked flask and add 50mL mass dropwise to the three-necked flask with a dropping funnel at a rate of 3mL/min. The potassium thiosulfate solution with a fraction of 5% is added dropwise, and then 70 mL of 33% dimethylamine aqueous solution, 40 mL of 37% formaldehyde solution and 30 mL of N-vinylpyrrolidone are added, and the temperature is heated to 70° C., heat-retaining and stirring for 2 h, taking out the reacted base film and washing twice with absolute ethanol and deionized water to obtain a heat-resistant and liquid-preserving lithium battery separator.

Example Embodiment

[0036] Example 2

[0037] Preparation of primary alumina flakes:

[0038] A circular aluminum sheet with a diameter of 17 mm was placed in 110 mL of absolute ethanol for ultrasonic treatment for 9 min, and the circular aluminum sheet was taken out and placed in 135 mL of 10% sodium hydroxide solution for ultrasonic treatment for 11 min, and the ultrasonic frequency was controlled to 32 kHz. The surface-treated aluminum sheet is obtained, and the surface-treated aluminum sheet is washed with deionized water for 4 times to obtain an anode aluminum sheet. The sheet is used as the anode, and the untreated high-purity aluminum sheet is placed in the mixed solution as the cathode, and polished at a voltage of 17V to obtain a polished anode aluminum sheet;

[0039] The graphite rod was used as the cathode, and the above-mentioned polished anode aluminum sheet was used as the anode into a beaker containing an oxalic acid solution with a mass fraction of 30%. In a water bath, electrolysis was performed at a voltage of 22V for 5.5h, and the obtained anode was a primary alumina sheet.

[0040] Preparation of base film:

[0041] Mix the phosphoric acid solution with a mass fraction of 6% and a chromic acid solution with a mass fraction of 2% in equal volumes to obtain a mixed acid solution. The sheet is used as the anode, and the graphite rod is used as the cathode. The secondary oxidation is carried out in the oxalic acid solution with a mass fraction of 30%, and the current voltage is controlled to 27V to obtain a secondary alumina sheet, which is equipped with an equal volume ratio of perchloric acid and anhydrous ethanol. The mixed solution, the secondary alumina sheet is placed in the mixed solution with 47V voltage through pulse voltage stripping to obtain anodic porous aluminum oxide film;

[0042] The above-mentioned anodic porous alumina membrane was placed in a phosphoric acid solution with a mass fraction of 5% for pore expansion for 32 minutes, and 45 g of silica gel powder was put into 110 mL of ammonia water with a mass fraction of 5%, and stirred and mixed for 7 minutes to obtain a silica gel liquid. The anodic porous alumina membrane was immersed in the silica gel solution, heated to 75°C, soaked for 2.5h, placed in a muffle furnace, heated to 1250°C, sintered for 5.5h, naturally cooled to room temperature, and discharged to obtain a base film.

[0043] Preparation of heat-resistant and liquid-retaining lithium battery separator:

[0044] Grind the calcium lignosulfonate solid for 25min to obtain calcium lignosulfonate powder, configure the calcium lignosulfonate powder into 420mL mass fraction of a 30% calcium lignosulfonate aqueous solution, and add it to a three-necked flask with a stirrer and a dropping funnel , after passing nitrogen through the three-necked flask to remove the air, adding a potassium hydroxide solution with a mass fraction of 40% to the three-necked flask to adjust the pH to 8, and stirring for 12min to obtain an alkalizing solution;

[0045] Add 85g acrylamide to the above-mentioned three-necked flask, start the stirrer, stir with a rotating speed of 320r/min, place the base film at the bottom of the three-necked flask and add 52 mL of mass dropwise to the three-necked flask with a dropping funnel at a rate of 4mL/min. The potassium thiosulfate solution with a fraction of 5% is added dropwise, and then 75 mL of 33% dimethylamine aqueous solution, 45 mL of 37% formaldehyde solution and 35 mL of N-vinylpyrrolidone are added, and the temperature is heated to At 75° C., the reaction was kept under stirring for 2.5 hours, and the reacted base film was taken out and washed twice with absolute ethanol and deionized water to obtain a heat-resistant and liquid-preserving lithium battery separator.

Example Embodiment

[0046] Example 3

[0047] Preparation of primary alumina flakes:

[0048] A circular aluminum sheet with a diameter of 18 mm was placed in 120 mL of absolute ethanol for ultrasonic treatment for 10 min, and the circular aluminum sheet was taken out and placed in 150 mL of 10% sodium hydroxide solution for ultrasonic treatment for 12 min, and the ultrasonic frequency was controlled to 35 kHz. The surface-treated aluminum sheet is obtained, and the surface-treated aluminum sheet is washed with deionized water for 5 times to obtain an anode aluminum sheet. The sheet is used as an anode, and the untreated high-purity aluminum sheet is placed in the mixed solution as a cathode, and polished at a voltage of 20V to obtain a polished anode aluminum sheet;

[0049] The graphite rod as the cathode and the above-mentioned polished anode aluminum sheet as the anode were placed in a beaker containing an oxalic acid solution with a mass fraction of 30%, the distance between the positive and negative electrodes of the battery was controlled to be 8 cm, and the beaker was placed on ice at 0 °C. In a water bath, electrolysis was conducted at a voltage of 25V for 6h, and the obtained anode was a primary alumina sheet.

[0050] Preparation of base film:

[0051] Mix the phosphoric acid solution with a mass fraction of 6% and a chromic acid solution with a mass fraction of 2% in equal volumes to obtain a mixed acid solution. After the primary oxidized aluminum flakes are soaked in the mixed acid solution for 7 hours, the primary aluminum oxide flakes are immersed in the mixed acid solution. As the anode and the graphite rod as the cathode, electrolysis was carried out in the oxalic acid solution with a mass fraction of 30% to carry out secondary oxidation. Mixed solution, the secondary alumina sheet is placed in the mixed solution and peeled off by pulse voltage at 50V to obtain an anodic porous alumina film;

[0052] The above-mentioned anodic porous alumina membrane was placed in a phosphoric acid solution with a mass fraction of 5% for pore expansion for 35 minutes, and 50 g of silica gel powder was put into 120 mL of ammonia water with a mass fraction of 5%, and stirred and mixed for 10 minutes to obtain a silica gel liquid. The anodic porous alumina membrane was immersed in the silica gel solution, heated to 80 °C, soaked for 3 hours, placed in a muffle furnace, heated to 1300 °C, sintered for 6 hours, naturally cooled to room temperature, and discharged to obtain the base film.

[0053]Preparation of heat-resistant and liquid-retaining lithium battery separator:

[0054] Grind the calcium lignosulfonate solid for 30min to obtain calcium lignosulfonate powder, configure the calcium lignosulfonate powder into 450mL mass fraction of 30% calcium lignosulfonate aqueous solution, and add it to a three-necked flask with a stirrer and a dropping funnel , after passing nitrogen through the three-necked flask to remove the air, adding a potassium hydroxide solution with a mass fraction of 40% to the three-necked flask to adjust the pH to 9, and stirring for 15min to obtain an alkaline solution;

[0055] Add 90g acrylamide to the above-mentioned three-necked flask, start the stirrer, stir at a rotating speed of 350r/min, place the base film at the bottom of the three-necked flask and add 55mL of mass dropwise to the three-necked flask with a dropping funnel at a rate of 5mL/min. The potassium thiosulfate solution with a fraction of 5% is added dropwise, and then 80 mL of a 33% dimethylamine aqueous solution, 50 mL of a 37% formaldehyde solution and 40 mL of N-vinylpyrrolidone are added, and the temperature is heated to At 80° C., the reaction was carried out under heat preservation and stirring for 3 hours, and the reacted base film was taken out and washed with absolute ethanol and deionized water for 3 times to obtain a heat-resistant and liquid-retaining lithium battery separator.

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Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Strong heat resistance

Highly-flame-retardant modified acrylate coating

InactiveCN104263182AGood flame retardancyStrong heat resistanceFireproof paintsPolyurea/polyurethane coatingsAmmonium polyphosphateEmulsion

Owner:WUHU SHUANGBAO BUILDING MATERIAL

High-permeability and high-temperature-resistant type acrylate pressure-sensitive adhesive and preparation method thereof

InactiveCN106632818AImprove permeabilityStrong heat resistanceEster polymer adhesivesPressure sensitive film/foil adhesivesFunctional monomerSolvent

Owner:HARBIN INST OF TECH WUXI RES INST OF NEW MATERIALS +1

Method for preparing heat-resistant liquid-holding lithium battery diaphragm

A lithium battery separator, heat-resistant technology, applied in battery pack parts, circuits, electrical components, etc., can solve the problems of poor wettability, shorten battery life, accelerate lithium-ion battery damage, etc., and achieve the effect of strong heat resistance

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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