Colloid electrolyte for colloid storage battery and preparation method of colloid electrolyte

Abstract

The invention belongs to the technical field of colloid storage batteries, and particularly relates to a colloid electrolyte for a colloid storage battery and a preparation method of the colloid electrolyte. Comprising the following raw materials in percentage by mass: 2-5% of fumed silica; 30-40% of sulfuric acid; 0.1 to 0.6 percent of ethylene glycol; 0.5 to 1.2 percent of disodium hydrogen phosphate; 0.1 to 1% of a thickening agent; the balance is water for the storage battery; and the thickening agent is guar gum or pectin. Ethylene glycol is introduced to assist in dispersing fumed silica, and disodium hydrogen phosphate is added to adjust the pH value of a colloidal stock solution, so that the storage stability is remarkably improved, the ion environment of the electrolyte is optimized, and the battery performance is enhanced; meanwhile, through the synergistic effect of the silicon dioxide and the thickening agent, the dosage of the silicon dioxide in the gel electrolyte is reduced, the internal resistance of the battery is effectively reduced, the capacity under different discharge rates is improved, and reliable technical support is provided for the application of the valve control type gel storage battery.

Description

Technical Field

[0001] The invention belongs to the technical field of colloidal storage batteries, and in particular relates to a colloidal electrolyte for colloidal storage batteries and a preparation method thereof. Background Art

[0002] The colloidal electrolyte of a valve-regulated colloidal battery is usually prepared by mixing a gelling agent (such as silica sol or silica) with a sulfuric acid solution. However, the electrolyte using silica as a gelling agent in the prior art has significant defects: on the one hand, the gelling time of silica is short, which makes it difficult to store the electrolyte for a long time, increasing the complexity of the production process; on the other hand, the content of silica directly affects the performance of the electrolyte. When its content is too low, hydration stratification is prone to occur. When the content is too high, the fluidity of the electrolyte decreases and the internal resistance of the battery increases, thereby affecting the charge and discharge efficiency and capacity of the battery. In addition, a variety of auxiliary additives need to be added in the traditional preparation process to stabilize the electrolyte system, which further increases the complexity of the formula and the production cost. Therefore, it is urgent to develop a colloidal electrolyte and a preparation method thereof with stable gel performance, simple process and both battery performance. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a colloidal electrolyte for a colloidal battery, which significantly improves the storage stability, optimizes the ionic environment of the electrolyte, and enhances the battery performance by introducing ethylene glycol to assist in dispersing fumed silica and adding disodium hydrogen phosphate to adjust the pH value of the colloidal stock solution; at the same time, through the synergistic effect of silica and a thickener, the amount of silica in the colloidal electrolyte is reduced, the internal resistance of the battery is effectively reduced, and the capacity at different discharge rates is increased, providing reliable technical support for the application of valve-regulated colloidal batteries.

[0004] Another object of the present invention is to provide a method for preparing a colloidal electrolyte for a colloidal storage battery, which adopts a staged preparation process to achieve ready-to-use electrolyte after mixing, thus overcoming the timeliness limitation of traditional processes.

[0005] The technical solution adopted by the present invention is as follows: The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 2~5%; Sulfuric acid: 30~40%; Ethylene glycol: 0.1~0.6%; Disodium hydrogen phosphate: 0.5~1.2%; Thickener: 0.1~1%; The balance is water for the battery; The thickener is guar gum or pectin; Preferably, the mass percentage of the pectin is 0.5-1.0%; the mass percentage of the guar gum is 0.10-0.50%.

[0006] The guar gum is hydroxypropyl guar gum.

[0007] The pectin is high methoxy pectin, and its methoxy content is 8.2-11.4wt.%.

[0008] The battery water is deionized water with a resistivity of ≥1×10 5 Ω·cm.

[0009] The fumed silica is hydrophilic fumed silica with a specific surface area of ​​175~225m 2 / g.

[0010] The sulfuric acid is CP grade sulfuric acid with a concentration of more than 95wt.%.

[0011] The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Add ethylene glycol to part of the battery water and stir thoroughly, then add fumed silica, stir and disperse using a dispersing device, and after the dispersion is uniform, add disodium hydrogen phosphate and continue to mix until uniform to obtain a colloidal stock solution; (2) Sulfuric acid is added to the remaining battery water to obtain a sulfuric acid solution, the sulfuric acid solution is mixed evenly with the colloidal stock solution in step (1), and then a thickener is added and stirred evenly to obtain a colloidal electrolyte for a colloidal battery.

[0012] In the step (1), the mass ratio of fumed silica to battery water is (10-20):(90-80).

[0013] In the step (1), the speed of the dispersion equipment is 2000-2500 r / min, and the dispersion time is 15-20 min.

[0014] In the step (1), the viscosity of the colloid stock solution is less than 10 Pa·s and the pH value is 8-10.

[0015] In step (2), the temperature of the sulfuric acid solution and the colloid stock solution must be cooled to below 15°C before mixing.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention introduces ethylene glycol to assist in dispersing fumed silica, and combines disodium hydrogen phosphate to adjust the pH value of the colloidal stock solution, thereby significantly extending the storage stability of the colloidal stock solution and simplifying the production process. When the colloidal stock solution is mixed with a sulfuric acid solution, phosphoric acid and sodium sulfate generated by the reaction of disodium hydrogen phosphate and sulfuric acid further optimize the ionic environment of the electrolyte and improve the electrical performance of the battery; (2) The present invention reduces the amount of silica and effectively inhibits the hydration stratification of the electrolyte through the synergistic effect of fumed silica and thickener (pectin or guar gum), thereby reducing the internal resistance of the battery and increasing the capacity at different discharge rates; (3) The present invention adopts a staged preparation process (i.e., first preparing a colloidal stock solution that can be stored for a long time, and then mixing it with a sulfuric acid solution as needed), realizing a "mix and use" production mode, which can ensure the perfusion fluidity of the electrolyte and avoid the timeliness limitation caused by the short gel time in the traditional process; and compared with the direct dispersion method (i.e., directly dispersing the silicon dioxide in a sulfuric acid solution), the acid resistance restriction on the dispersion equipment is eliminated, thereby reducing the production input cost; (4) The present invention reduces the complexity of raw materials by reducing the types of auxiliary additives, and improves production efficiency and product consistency by optimizing process parameters. DETAILED DESCRIPTION

[0017] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0018] The raw materials used in the examples and comparative examples are conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0019] Some of the raw materials used in the examples and comparative examples are described as follows: The guar gum is hydroxypropyl guar gum; The methoxy content of the pectin is (10±1) wt.%; The fumed silica is hydrophilic fumed silica with a specific surface area of ​​(200±25) m 2 / g; The sulfuric acid is CP grade sulfuric acid with a concentration of (95.5±0.5) wt.%; The battery water is deionized water, and its resistivity is (5×10 5 )Ω·cm.

[0020] Example 1 The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 2%; Sulfuric acid: 38.7%; Ethylene glycol: 0.1%; Disodium hydrogen phosphate: 0.5%; Pectin: 1%; The balance is water for the battery; The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Add 0.5 kg of ethylene glycol to 87 kg of battery water and stir well, then add 10 kg of fumed silica and stir and disperse using a disperser. The speed of the disperser is 2000 r / min and the dispersion time is 15 min. After the dispersion is uniform, add 2.5 kg of disodium hydrogen phosphate and continue to mix until uniform to obtain a colloidal stock solution. The viscosity is measured to be 0.8 Pa·s and the pH value is 8.7. The obtained colloidal stock solution is cooled to 10°C for use. (2) 38.7 kg of sulfuric acid is added to 40.3 kg of battery water to obtain 79 kg of sulfuric acid solution, which is cooled to 10° C. and then mixed with 20 kg of the cooled colloidal stock solution in step (1) to obtain a colloidal electrolyte for a colloidal battery. Then, 1 kg of pectin is added and stirred to obtain a colloidal electrolyte for a colloidal battery.

[0021] The colloidal electrolyte of the colloidal battery was poured into the GFMJ-200 battery, and after charging (charging at a constant current of 20A until the voltage rises to 2.7V and remains stable for 3h) and activation, it was left to stand for 12h to allow the electrolyte to fully gel.

[0022] Example 2 The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 5%; Sulfuric acid: 31%; Ethylene glycol: 0.5%; Disodium hydrogen phosphate: 1%; Guar gum: 0.1%; The balance is water for the battery; The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Add 2.0 kg of ethylene glycol to 74 kg of battery water and stir well, then add 20 kg of fumed silica and stir and disperse using a disperser. The speed of the disperser is 2500 r / min and the dispersion time is 20 min. After the dispersion is uniform, add 4 kg of disodium hydrogen phosphate and continue to mix until uniform to obtain a colloidal stock solution. The viscosity is measured to be 7 Pa·s and the pH value is 9.3. The obtained colloidal stock solution is cooled to 10°C for standby use. (2) 31 kg of sulfuric acid is added to 43.9 kg of battery water to obtain 74.9 kg of sulfuric acid solution, which is cooled to 10° C. and then mixed with 25 kg of the cooled colloidal stock solution in step (1). Then, 0.1 kg of guar gum is added and stirred to obtain a colloidal electrolyte for a colloidal battery.

[0023] The colloidal electrolyte of the above-mentioned colloidal storage battery was poured into a 4 OPzV 200 battery, and after charging (charging at a constant current of 20A until the voltage rises to 2.7V and remains stable for 3h) and activation, it was left to stand for 12h to allow the electrolyte to fully gel.

[0024] Example 3 The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 4.5%; Sulfuric acid: 35.6%; Ethylene glycol: 0.6%; Disodium hydrogen phosphate: 1.2%; Pectin: 0.5%; The balance is water for the battery; The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Add 2.0 kg of ethylene glycol to 79 kg of battery water and stir well, then add 15 kg of fumed silica and stir and disperse using a disperser. The speed of the disperser is 2200 r / min and the dispersion time is 20 min. After the dispersion is uniform, add 4 kg of disodium hydrogen phosphate and continue to mix until uniform to obtain a colloidal stock solution. The viscosity is measured to be 4.2 Pa·s and the pH value is 8.6. The obtained colloidal stock solution is cooled to 10°C for standby use. (2) 35.6 kg of sulfuric acid is added to 33.9 kg of battery water to obtain 69.5 kg of sulfuric acid solution, which is cooled to 10° C. and then mixed with 30 kg of the cooled colloidal stock solution in step (1). Then, 0.5 kg of pectin is added and stirred to obtain a colloidal electrolyte for a colloidal battery.

[0025] The colloidal electrolyte of the above-mentioned colloidal battery was poured into a 6 OPzV 600 battery, charged (charged at a constant current of 60A until the voltage rose to 2.7V and remained stable for 3h) and activated, and then left to stand for 12h to allow the electrolyte to fully gel.

[0026] Comparative Example 1 The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 2%; Sulfuric acid: 38.7%; Ethylene glycol: 0.1%; Disodium hydrogen phosphate: 0.5%; The balance is water for the battery; The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Same as Example 1; (2) 38.7 kg of sulfuric acid is added to 41.3 kg of battery water to prepare 80 kg of sulfuric acid solution, which is cooled to 10° C. and then mixed with 20 kg of the cooled colloidal stock solution in step (1) to obtain a colloidal electrolyte for a colloidal battery.

[0027] The colloidal electrolyte for the colloidal battery was poured into a GFMJ-200 battery, and after charging (charging at a constant current of 20 A until the voltage rises to 2.7 V and stabilizes for 3 hours) and activation, the battery was left to stand for 12 hours. The electrolyte showed gel-acid separation, indicating that the pectin added in Example 1 can play a role in thickening and stabilization.

[0028] Comparative Example 2 The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 5%; Sulfuric acid: 31%; Ethylene glycol: 0.5%; Disodium hydrogen phosphate: 1%; The balance is water for the battery; The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Same as Example 2; (2) 31 kg of sulfuric acid is added to 44 kg of battery water to prepare 75 kg of sulfuric acid solution, which is cooled to 10° C. and then mixed with 25 kg of the cooled colloidal stock solution in step (1) to obtain a colloidal electrolyte for a colloidal battery.

[0029] The colloidal electrolyte for the colloidal battery was poured into a 4 OPzV 200 battery, and after charging (charging at a constant current of 20 A until the voltage rises to 2.7 V and stabilizes for 3 hours) and activation, the battery was left to stand for 12 hours. The electrolyte showed gel-acid separation, indicating that the guar gum added in Example 2 can play a role in thickening and stabilization.

[0030] In the case of not adding a thickener, for a colloidal electrolyte system with the same sulfuric acid content, in order to achieve an ideal gelation effect, the amount of silicon dioxide added in the colloidal electrolyte needs to be increased, as shown in Comparative Examples 3 and 4.

[0031] Comparative Example 3 The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 3.5%; Sulfuric acid: 38.7%; Ethylene glycol: 0.175%; Disodium hydrogen phosphate: 0.875%; The balance is water for the battery; The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Same as Example 1; (2) 38.7 kg of sulfuric acid is added to 26.3 kg of battery water to prepare 65 kg of sulfuric acid solution, which is cooled to 10° C. and then mixed with 35 kg of the cooled colloidal stock solution in step (1) to obtain a colloidal electrolyte for a colloidal battery.

[0032] The colloidal electrolyte of the colloidal battery was poured into the GFMJ-200 battery, and after charging (charging at a constant current of 20A until the voltage rises to 2.7V and stabilizes for 3h), it was left to stand for 12h to allow the electrolyte to fully gel.

[0033] Comparative Example 4 The colloidal electrolyte for the colloidal storage battery comprises the following raw materials in percentage by mass: Fumed silica: 7%; Sulfuric acid: 31%; Ethylene glycol: 0.7%; Disodium hydrogen phosphate: 1.4%; The balance is water for the battery; The method for preparing the colloidal electrolyte for the colloidal battery comprises the following steps: (1) Same as Example 2; (2) 31 kg of sulfuric acid is added to 34 kg of battery water to prepare 65 kg of sulfuric acid solution, which is cooled to 10° C. and then mixed with 35 kg of the cooled colloidal stock solution in step (1) to obtain a colloidal electrolyte for a colloidal battery.

[0034] The colloidal electrolyte of the above-mentioned colloidal battery was poured into a 4 OPzV 200 battery, charged (charged at a constant current of 20 A until the voltage rose to 2.7 V and remained stable for 3 h), activated, and then left to stand for 12 h to allow the electrolyte to fully gel.

[0035] With reference to YDT 1360-2005, the performance of the batteries assembled in Examples 1-2 and Comparative Examples 3-4 were tested respectively. The test results are shown in Table 1.

[0036] Table 1 Performance test results

[0037] In Table 1, the same type of dry batteries are used in Example 1 and Comparative Example 3, and the same type of dry batteries are used in Example 2 and Comparative Example 4. In addition, the sulfuric acid content in the electrolyte used in Example 1 and Comparative Example 3 is the same, and the sulfuric acid content in the electrolyte used in Example 2 and Comparative Example 4 is also the same. Under the premise of ensuring the same gel effect, the colloidal electrolyte in Example 1 and Example 2 reduces the amount of silicon dioxide by adding a thickener.

[0038] It can be seen from the test data in Table 1 that, compared with the corresponding comparative example, the battery internal resistance in the embodiment is lower, and the battery discharge performance, especially the high-rate discharge performance, is more excellent.

[0039] Comparative Example 5 The preparation method of the colloid stock solution comprises the following steps: 0.5 kg of ethylene glycol was added to 89.5 kg of battery water and stirred thoroughly. Then 10 kg of fumed silica was added and stirred and dispersed using a disperser. The speed of the disperser was 2000 r / min and the dispersion time was 15 min. The viscosity was measured to be 10 Pa·s and the pH value was 4.2.

[0040] Comparative Example 6 The preparation method of the colloid stock solution comprises the following steps: 10 kg of fumed silica was added to 87.5 kg of battery water, and the mixture was stirred and dispersed by a disperser at a speed of 2000 r / min for 30 min. After uniform dispersion, 2.5 kg of disodium hydrogen phosphate was added and the mixture was mixed until uniform to obtain a colloidal stock solution, whose viscosity was measured to be 0.7 Pa·s and pH value was 9.1.

[0041] Comparative Example 7 The preparation method of the colloid stock solution comprises the following steps: 2.0 kg of ethylene glycol was added to 78 kg of battery water and stirred thoroughly. Then 20 kg of fumed silica was added and stirred and dispersed using a disperser. The speed of the disperser was 2500 r / min and the dispersion time was 20 min. The viscosity was measured to be 40 Pa·s and the pH value was 3.3.

[0042] Comparative Example 8 The preparation method of the colloid stock solution comprises the following steps: 20 kg of fumed silica was added to 76 kg of battery water and stirred and dispersed by a disperser at a speed of 2500 r / min for 40 min. After uniform dispersion, 4 kg of disodium hydrogen phosphate was added and mixed until uniform. The viscosity was measured to be 6.3 Pa·s and the pH value was 9.8. Comparing Comparative Example 5 and Comparative Example 7 with Example 1 and Example 2, respectively, it can be seen that in Example 1 and Example 2, since disodium hydrogen phosphate is added to the colloid stock solution, the viscosity of the colloid stock solution decreases significantly.

[0043] Comparing Comparative Examples 6 and 8 with Example 1 and Example 2, respectively, it can be seen that in Example 1 and Example 2, the dispersion time of fumed silica in battery water is shortened due to the addition of ethylene glycol to the colloid stock solution.

[0044] At room temperature, the colloid stock solutions prepared in Example 1, Example 2, Comparative Example 5 and Comparative Example 7 were allowed to stand for 2 h, 6 h, 12 h, 24 h, 48 h and 72 h, respectively, and the fluidity of the colloid stock solutions was observed. The results are shown in Table 2.

[0045] Table 2 Fluidity of colloid stock solution

[0046] It can be seen from Table 2 that, compared with Comparative Examples 5 and 7, the gel time of the colloid stock solutions of Examples 1 and 2 was significantly prolonged due to the addition of disodium hydrogen phosphate, and the fluidity did not change significantly within 72 hours, and the processability was better.

Claims

1. A colloidal electrolyte for a colloidal storage battery, characterized in that: The following raw materials are included in the following mass percentages: Fumed silica: 2~5%; Sulfuric acid: 30~40%; Ethylene glycol: 0.1~0.6%; Disodium hydrogen phosphate: 0.5~1.2%; Thickener: 0.1~1%; The balance is water for the battery; The thickener is guar gum or pectin; The battery water is deionized water.

2. The colloidal electrolyte for colloidal storage battery according to claim 1, characterized in that: The specific surface area of ​​the fumed silica is 175-225 m 2 / g.

3. The colloidal electrolyte for colloidal storage battery according to claim 1, characterized in that: The guar gum is hydroxypropyl guar gum.

4. The colloidal electrolyte for colloidal storage battery according to claim 1, characterized in that: The methoxy content of the pectin is 8.2-11.4 wt.%.

5. The colloidal electrolyte for colloidal storage battery according to claim 1, characterized in that: The resistivity of the battery water is ≥1×10 5 Ω·cm.

6. A method for preparing a colloidal electrolyte for a colloidal storage battery according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Add ethylene glycol to part of the battery water and stir thoroughly, then add fumed silica, stir and disperse using a dispersing device, and after the dispersion is uniform, add disodium hydrogen phosphate and continue to mix until uniform to obtain a colloidal stock solution; (2) Sulfuric acid is added to the remaining battery water to obtain a sulfuric acid solution, the sulfuric acid solution is mixed evenly with the colloidal stock solution in step (1), and then a thickener is added and stirred evenly to obtain a colloidal electrolyte for a colloidal battery.

7. The method for preparing a colloidal electrolyte for a colloidal storage battery according to claim 6, characterized in that: In the step (1), the mass ratio of fumed silica to battery water is (10-20):(90-80).

8. The method for preparing a colloidal electrolyte for a colloidal storage battery according to claim 6, characterized in that: In the step (1), the speed of the dispersion equipment is 2000-2500 r / min, and the dispersion time is 15-20 min.

9. The method for preparing a colloidal electrolyte for a colloidal storage battery according to claim 6, characterized in that: In the step (1), the viscosity of the colloid stock solution is less than 10 Pa·s, and the pH value is 8-10.

10. The method for preparing a colloidal electrolyte for a colloidal storage battery according to claim 6, characterized in that: In step (2), the temperature of the sulfuric acid solution and the colloid stock solution must be cooled to below 15°C before mixing.

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