Electrolyte for lead storage battery, formation process and preparation method of lead storage battery

Abstract

The invention discloses an electrolyte for a lead storage battery, a formation charge-discharge process and a preparation method of the lead storage battery, and relates to the technical field of storage batteries. A modified biological bacterium additive is added to a common electrolyte of a battery in production, the activity of the electrolyte is improved, the influence of electrolyte impurities is reduced, and charging voltage value limitation is carried out in a formation charging and discharging process stage to prevent internal electrolyzed water of the battery from being overcharged; therefore, the density consistency and stability of the battery electrolyte are improved, the utilization rate of sulfate ions is improved, the charge-discharge efficiency of the battery is improved, grid corrosion and battery self-discharge of a battery pole plate caused by a cyclic electrochemical action reaction are restrained, and the capacity retention ratio and the cycle life performance of the battery are improved. And a formation charge-discharge process is optimized, so that the battery capacity matching rate and the performance consistency are improved, and the cycle life performance of the battery is improved.

Description

Technical Field

[0001] The invention relates to the technical field of storage batteries, and in particular to an electrolyte for a lead-acid battery, a formation process and a preparation method of the lead-acid battery. Background Art

[0002] Lead-acid batteries have been widely used in energy storage, car start-stop systems, backup power supplies and other fields due to their relatively low cost, stable performance and mature technology. However, in actual use, the performance of lead-acid batteries is often affected by a variety of environmental factors, climatic conditions and user habits, resulting in the actual service life and performance of the battery often being lower than theoretical expectations. The most prominent problem is premature battery capacity decay and failure.

[0003] The mudding and shedding of the positive plate and the sulfation of the negative plate are one of the main reasons for the shortened life of lead-acid batteries. The mudding and shedding of the positive plate is mainly due to the gradual peeling of the active material from the plate due to physical and chemical effects during the long-term charge and discharge cycle, forming the so-called "mudification" phenomenon, which not only reduces the effective substances participating in the electrochemical reaction, but also may cause short circuits between the plates and reduce battery efficiency. The sulfation of the negative plate is a more complicated process, which usually occurs when the battery is over-discharged or not charged for a long time after discharge. At this time, the lead on the negative plate will be converted into lead sulfate, and these lead sulfate particles will dissolve in the electrolyte and reach a saturated state. With the change of ambient temperature, especially under low temperature conditions, these dissolved lead sulfates will recrystallize to form larger lead sulfate particles. These particles have poor conductivity and high resistance, and are difficult to be completely converted into active materials during the charging process, resulting in a gradual decrease in battery capacity until failure.

[0004] The precipitation and crystallization of lead sulfate is a dynamic process, which is affected by many factors such as battery usage conditions, electrolyte composition, temperature fluctuations, etc. Especially in high-frequency charging and discharging application scenarios such as energy storage and start-stop batteries, since the battery needs to work frequently under different load conditions and may face long periods of idleness, it is more likely to cause lead sulfate precipitation and crystallization problems, thereby accelerating the decline of battery performance.

[0005] As the core component of lead-acid batteries, the performance of electrolyte has a crucial impact on the overall performance of the battery. It is not only responsible for transporting metal ions between the positive and negative electrodes and maintaining the electrochemical reaction balance inside the battery, but also directly affects the battery's specific capacity, operating temperature range, cycle efficiency and safety performance. Therefore, choosing a suitable electrolyte formula is the key to improving the performance of lead-acid batteries and extending their service life. The ideal electrolyte should have the characteristics of high ionic conductivity, good chemical stability, a wide operating temperature range and low corrosiveness to ensure that the battery can maintain efficient and stable operation under various conditions of use.

[0006] In addition, the battery charge and discharge formation process is also an important factor affecting the performance of lead-acid batteries. By optimizing the formation process parameters, such as formation current, voltage, time and temperature, the internal structure of the battery can be further improved, the utilization rate of active substances can be increased, and the precipitation and crystallization of lead sulfate can be reduced, thereby extending the service life of the battery. Therefore, developing an electrolyte formula that not only meets the performance requirements of lead-acid batteries, but also has good economy and environmental protection, as well as a matching formation charge and discharge process, is of great significance for improving the overall performance of lead-acid batteries, reducing the cost of use, and promoting the sustainable development of the lead-acid battery industry. Summary of the invention

[0007] Based on the deficiencies in the prior art, the present invention provides an electrolyte for a lead-acid battery, a formation process and a preparation method of the lead-acid battery. A modified biological bacteria additive is added to the ordinary electrolyte of the battery in production to increase the activity of the electrolyte and reduce the influence of electrolyte impurities. In the formation charge and discharge process stage, the charging voltage value is limited to prevent the battery from being overcharged and electrolyzing water inside, thereby improving the consistency and stability of the battery electrolyte density, improving the utilization rate of sulfate ions, and improving the battery charge and discharge efficiency, preventing the battery plate from corroding the grid and the battery from self-discharging due to the cyclic electrochemical reaction, and improving the battery capacity retention rate and cycle life performance; the formation charge and discharge process is optimized, thereby improving the battery capacity grouping rate and performance consistency, and improving the battery cycle life performance.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides an electrolyte for a lead-acid battery, comprising a sulfuric acid solution and an additive, wherein the additive comprises at least one microorganism, the microorganism is used to increase the activity of the electrolyte, and the mass ratio of the microorganism to the sulfuric acid solution is 3.0-3.5:100.

[0010] Specifically, the additives also include sodium sulfate and fumed silica, the added mass of sodium sulfate is 0.75% to 0.85% of the mass of the sulfuric acid solution, and the added amount of fumed silica is 0.4% to 0.6% of the mass of the sulfuric acid solution. The density of the sulfuric acid solution is 1.242 to 1.246 g / cm 3 .

[0011] Preferably, the microorganism is at least one of active nitrifying bacteria, denitrifying bacteria, and photosynthetic bacteria.

[0012] The present invention also provides a lead storage battery, wherein the electrolyte used is the above electrolyte.

[0013] The present invention also provides a method for preparing the lead-acid battery, comprising the following steps:

[0014] (1) quantitatively adding acid to a single cell of a lead-acid battery by adding the above-mentioned electrolyte; the amount of acid added in the quantitative acid addition is 14.0 to 15.0 g / Ah;

[0015] (2) several lead-acid batteries filled with electrolyte are connected in series in a loop and placed in a water tank, and then the formation process is controlled at a constant water temperature of 32 to 35° C. to charge and discharge until the end;

[0016] (3) 5 to 10 minutes before the formation online discharge capacity test phase, vacuum pumping is performed for 5 to 10 seconds;

[0017] (4) After the formation is completed, cover the safety valve, let it stand for 2 hours, measure the open circuit voltage and internal resistance, and then start grouping.

[0018] Specifically, the steps of charging and discharging during formation include:

[0019] SI: Charge at constant current 0.1C2A for 5.0h;

[0020] S2: charge at a constant current of 0.2C2A for 5.0h;

[0021] S3: Charge at a constant current of 0.4C2A for 4.0h;

[0022] S4: Charge at a constant current of 0.6C2A for 3.0h;

[0023] S5: charge at a constant current of 0.8C2A for 2.0h;

[0024] S6: Charge for 1.0h at a constant voltage of 16.4V and a current limit of 1.0C2A;

[0025] S7: Discharge at a constant current of 1.0C2A for 30 min;

[0026] S8: charge at a constant current of 0.8C2A for 1.0h;

[0027] S9: Charge for 2.5h at a constant voltage of 16.6V and a current limit of 0.7C2A;

[0028] S10: Discharge at a constant current of 1.0C2A for 45 min;

[0029] S11: charge at a constant current of 0.8C2A for 1.0h;

[0030] S12: Charge for 3.5h at a constant voltage of 16.8V and a current limit of 0.7C2A;

[0031] S13: Discharge at a constant current of 1.0C2A for 55 min;

[0032] S14: charge at a constant current of 0.8C2A for 1.0h;

[0033] S15: Charge for 4.5h at a constant voltage of 17.0V and a current limit of 0.7C2A;

[0034] S16: Discharge at a constant current of 1.0C2A for 1.0h 10min;

[0035] S17: Charge at a constant current of 0.8C2A for 3.0h;

[0036] S18: Charge at a constant current of 0.7C2A for 3.0h;

[0037] S19: Charge for 3.5h at a constant voltage of 17.2V and a current limit of 0.6C2A;

[0038] S20: let stand for 10 minutes, and then vacuumize for 5 to 10 seconds;

[0039] S21: Discharge at a constant current of 1.0C2A for 1.0h 40min;

[0040] S22: Discharge at a constant current of 1.0C2A to 10.0V / pcs;

[0041] S23: charge at a constant current of 0.8C2A for 2.5h;

[0042] S24: charge at a constant current of 0.7C2A for 1.0h;

[0043] S25: charge at a constant current of 0.6C2A for 1.0h;

[0044] S26: charge at a constant current of 0.24C2A for 30 min;

[0045] S27: Charge at a constant current of 0.05C2A for 3.0h;

[0046] S28: End.

[0047] Among them, C2 is the 2-hour rate rated capacity.

[0048] Preferably, in steps S6, S9, S12, S15, and S19, voltage limiting control is performed, and the voltages are respectively: 16.4V, 16.6V, 16.8V, 17.0V, and 17.2V. The charging voltage value is limited to prevent overcharging, and to avoid excessively high charging voltage, which causes the hydrogen in the electrolyte inside the battery to precipitate and produce the phenomenon of "electrolyzed water".

[0049] In step S20, stand for 10 minutes and vacuumize with negative pressure for 5 to 10 seconds; as long as negative pressure is used for vacuumization, the embodiment of the present invention uses negative pressure of -0.085Mpa for vacuumization as an example. In the electrochemical principle of the discharge process stage, the electrolyte will be adsorbed by the internal pole group of the battery to generate lead sulfate and water. The use of vacuumization can ensure that the air bubbles inside the battery pole group can be fully removed, and the active substances can fully participate in the chemical reaction of the electrolyte.

[0050] Specifically, in step S22, the capacity discharge detection is divided into 6 levels according to the voltage value, namely, 0 to 5, as the first grouping of the online capacity inspection of the lead-acid battery.

[0051] 10.0V≤0 gear<10.15V;

[0052] 10.15V≤1st gear<10.30V;

[0053] 10.30V≤2nd gear<10.45V;

[0054] 10.45V≤3rd gear<10.60V;

[0055] 10.60V≤4th gear<10.75V;

[0056] 10.75V≤5th gear<10.90V.

[0057] The voltage value <10.0V is a low-grade lead-acid battery, and the voltage value ≥10.9V is a high-grade lead-acid battery. Both are scrapped. Carry out capacity classification and exclude abnormal batteries in high and low grades.

[0058] The free acid is extracted during charging within a specified voltage range, that is, the free acid is extracted when the voltage after charging in step S27 is between 16.30 and 16.60 V.

[0059] Beneficial effects of the present invention:

[0060] The composite additive electrolyte, the formation charge-discharge process, and the preparation method of the lead-acid battery of the present invention add modified biological bacteria additives to the ordinary electrolyte of the battery in production to increase the activity of the electrolyte and reduce the influence of electrolyte impurities. In the formation charge-discharge process stage, the charging voltage value is limited to prevent the battery from overcharging and electrolyzing water inside, thereby improving the consistency and stability of the battery electrolyte density, improving the utilization rate of sulfate ions, and improving the battery charge-discharge efficiency, preventing the battery plate from corroding the grid and the battery self-discharge due to the cyclic electrochemical reaction, and improving the battery capacity retention rate and cycle life performance; and optimizing the formation charge-discharge process, thereby improving the battery capacity grouping rate and performance consistency, and improving the battery cycle life performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The cycle life performance of Example 1;

[0062] Figure 2 The cycle life performance of Example 2;

[0063] Figure 3 The cycle life performance of Example 3;

[0064] Figure 4 The cycle life performance of Comparative Example 1;

[0065] Figure 5 The cycle life performance of Comparative Example 2;

[0066] in, Figure 1 to Figure 5 In the figure, the horizontal axis is the number of cycles, and the vertical axis is the discharge time, in min. DETAILED DESCRIPTION

[0067] The microorganisms used in the embodiments of the present invention are all VOONLINE brand β3 nitrifying bacteria liquid, which mainly includes active nitrifying bacteria, denitrifying bacteria, photosynthetic bacteria and the like.

[0068] Example 1

[0069] Prepare the pre-made additive solution first, prepare 100kg density 1.242g / cm 3 A mixed sulfuric acid solution (containing sodium sulfate, accounting for 0.75% of the mass of the sulfuric acid solution; fumed silica, accounting for 0.5% of the mass of the sulfuric acid solution) is prepared, and then 3.3 kg of nitrifying bacteria solution is slowly injected into the mixed sulfuric acid solution and slowly stirred to form a composite electrolytic solution.

[0070] The graphene batteries of 1# code loop 12V / 20Ah were quantitatively acidified, with the acid addition amount of 299g / cell and the acid addition density of 1.242g / cm 3, and placed in a water tank, controlled at a constant water temperature of 32-35°C to carry out the formation process charging and discharging until the end, the circuit is connected in series with 18 batteries to carry out the formation process charging and discharging in Table 1; when the process is executed to steps 6, 9, 12, 15 and 19, the charging state is voltage limited; when it comes to step 22, the discharge capacity of each battery in the entire circuit is classified into gears, wherein the gears are 0-5 gears, a total of 6 gears, 10.0V≤0 gear<10.15V; 10.15V≤1 gear<10.30V; 10.30 V≤2 gear<10.45V; 10.45V≤3 gear<10.60V; 10.60V≤4 gear<10.75V; 10.75V≤5 gear<10.90V; voltage value <10.0V is a low-grade lead-acid battery, voltage value ≥10.9V is a high-grade lead-acid battery, high and low-grade abnormal batteries are marked and subsequently scrapped offline; when proceeding to step 27, the voltage value is 16.35V / battery, the stage process is completed by negative pressure extraction of free acid for each battery, and the formation process is continued to be executed to the end.

[0071] Table 1

[0072]

[0073] After the circuit battery has completed the formation process, all batteries are left to stand for 2 hours before the battery cover is sealed to complete the manufacturing of the finished battery.

[0074] Example 2

[0075] Prepare the pre-made additive solution first, prepare 100kg density 1.244g / cm 3 Sulfuric acid solution (containing sodium sulfate, accounting for 0.70% of the mass of the sulfuric acid solution; fumed silica, accounting for 0.4% of the mass of the sulfuric acid solution), and then 3.3kg of nitrifying bacteria solution is slowly injected into the mixed sulfuric acid solution and slowly stirred to form a composite electrolytic solution.

[0076] The graphene batteries of 12V / 20Ah in the 2# code loop were quantitatively acidified, with an acid addition amount of 299g / cell and an acid density of 1.244g / cm 3 , and placed in a water tank, controlled at a constant water temperature of 32-35°C for charging and discharging to the end of the formation process, and 18 batteries are connected in series in the circuit to perform charging and discharging of the formation process in Table 1; when the process executes to steps 6, 9, 12, 15 and 19, the charging state is voltage limited; when it reaches step 22, the discharge capacity of each battery in the entire circuit is classified by gear, and the high and low gear abnormal batteries are marked and subsequently scrapped; when it reaches step 27, the voltage value reaches 16.40V / battery, and the negative pressure extraction of free acid from each battery completes the stage process, and the formation process continues to be executed to the end.

[0077] Example 3

[0078] Prepare the pre-made additive solution first, and prepare 100kg of density 1.246g / cm 3 Sulfuric acid solution (containing sodium sulfate, accounting for 0.80% of the mass of the sulfuric acid solution; fumed silica, accounting for 0.6% of the mass of the sulfuric acid solution), and then 3.3kg of nitrifying bacteria solution is slowly injected into the mixed sulfuric acid solution and slowly stirred to form a composite electrolytic solution.

[0079] The graphene batteries of the 12V / 20Ah graphene batteries in the 3# code loop were quantitatively acidified, with an acid addition amount of 299g / cell and an acid density of 1.246g / cm 3 , and placed in a water tank, controlled at a constant water temperature of 32-35°C for charging and discharging to the end of the formation process, and 18 batteries are connected in series in the circuit to perform charging and discharging of the formation process in Table 1; when the process executes to steps 6, 9, 12, 15 and 19, the charging state is voltage limited; when it reaches step 22, the discharge capacity of each battery in the entire circuit is classified by gear, and the abnormal high and low gear batteries are marked and subsequently scrapped offline; when it reaches step 27, the voltage value reaches 16.50V / battery, and the negative pressure extraction of free acid from each battery completes the stage process, and the formation process continues to be executed to the end.

[0080] Comparative Example 1

[0081] 18 12V / 20Ah batteries in one circuit are added with a vacuum acidifier to obtain a density of 1.242g / cm 3 300 g of sulfuric acid solution was injected into each cell, and the formation charge and discharge process was carried out. After the acid extraction process in step 28, the program was terminated and the finished battery was completed, as shown in Table 2.

[0082] Table 2

[0083] step Way Current / A Time / h 1 Charge 1.0 00：30：00 2 Charge 3.5 01：30：00 3 Charge 6.5 02：00：00 4 still 0 00：10：00 5 Charge 7.8 06：00：00 6 Discharge -10 00：24：00 7 Charge 7.8 01：30：00 8 Charge 6.5 02：00：00 9 Discharge -10 00：24：00 10 Charge 7.8 01：30：00 11 Charge 6.5 02：00：00 12 Discharge -10 00：30：00 13 Charge 7.8 01：30：00 14 Charge 6.5 03：00：00 15 Discharge -10 01：00：00 16 Charge 7.8 02：00：00 17 Discharge -10 00：06：00 18 Charge 7.8 02：30：00 19 Discharge -10 00：06：00 20 Charge 7.8 03：00：00 21 Charge 6.2 03：00：00 22 still 0 00：10：00 23 Discharge -10 01：45：00 24 Discharge -10 10.5V / single 25 Charge 7.8 02：30：00 26 Charge 6.5 02：50：00 27 Charge 1.5 01：00：00 28 Charge 0.6 03：00：00 29 Finish

[0084] Note: In step 28, acid extraction is performed after charging for 1.5 hours.

[0085] Comparative Example 2

[0086] 18 12V / 20Ah batteries in one circuit are added with a vacuum acidifier to make the battery with a density of 1.244g / cm 3 302 g of sulfuric acid solution is injected into each cell, and the formation charge and discharge process is carried out. After the acid extraction process in step 28, the program is terminated and the finished battery is completed, see Table 2.

[0087] Test Example 1

[0088] Six finished 12V / 20Ah batteries (same 3 gears) of Examples 1, 2 and 3 were sampled, and six finished 12V / 20Ah batteries (same 3 gears) of Comparative Examples 1 and 2 were sampled, and batteries were manufactured according to the three examples, and performance tests were compared with conventional comparative batteries. Figures 1 to 3 For example, Figures 4-5 The cycle life performance results of the comparative battery and specific battery parameters are shown in Table 3.

[0089] Table 3

[0090] Case <![CDATA[Acid addition density g / cm 3 > Acid addition per cell / g <![CDATA[C2 capacity / Ah]]> Lifespan / Number of times Weight / kg Example 1 1.242 299 20.8 625 6.15 Example 2 1.244 299 20.9 602 6.13 Example 3 1.246 299 20.8 601 6.12 Comparative Example 1 1.242 300 20.2 480 6.13 Comparative Example 2 1.244 302 20.3 455 6.14

[0091] From the performance test parameters in Table 3 above, it can be seen that the C2 capacity of the battery in Examples 1 to 3 at room temperature is significantly higher than that of the comparative example, indicating that under the same type of battery plates, the same material conditions, different formulations of electrolytes and formation charge and discharge processes, the battery charge and discharge efficiency and acceptance capacity are different. The cycle life is different, and the life is increased by about 130 times.

Claims

1. An electrolyte for a lead-acid battery, comprising a sulfuric acid solution and an additive, characterized in that: The additive includes at least one microorganism, and the microorganism is used to increase the activity of the electrolyte. The mass ratio of the microorganism to the sulfuric acid solution is 3.0-3.5:

100.

2. The electrolyte for lead-acid battery according to claim 1, characterized in that: The additives also include sodium sulfate and fumed silicon dioxide. The added mass of sodium sulfate is 0.75% to 0.85% of the mass of the sulfuric acid solution, and the added mass of fumed silicon dioxide is 0.4% to 0.6% of the mass of the sulfuric acid solution.

3. The electrolyte for lead-acid battery according to claim 1, characterized in that: The density of the sulfuric acid solution is 1.242-1.246 g / cm 3 .

4. The electrolyte for lead-acid battery according to claim 1, characterized in that: The microorganism is at least one of active nitrifying bacteria, denitrifying bacteria, and photosynthetic bacteria; The additive is β3 nitrifying bacteria liquid from the Veuvelan brand.

5. A lead-acid battery, characterized in that: Use the electrolyte described in any one of claims 1 to 4.

6. The method for preparing a lead-acid battery according to claim 5, characterized in that: The following steps are involved: (1) quantitatively adding acid to a single cell of a lead-acid battery and adding the electrolyte according to any one of claims 1 to 4; (2) several lead-acid batteries filled with electrolyte are connected in series in a loop and placed in a water tank, and then the formation process is controlled at a constant water temperature of 32 to 35° C. to charge and discharge until the end; (3) 5 to 10 minutes before the formation online discharge capacity test phase, vacuum pumping is performed for 5 to 10 seconds; (4) After the formation is completed, the safety valve is covered and the lead-acid battery is obtained after standing.

7. The preparation method according to claim 6, characterized in that: The steps of charging and discharging during formation include: S1: charge at a constant current of 0.1C2A for 5.0h; S2: charge at a constant current of 0.2C2A for 5.0h; S3: Charge at a constant current of 0.4C2A for 4.0h; S4: Charge at a constant current of 0.6C2A for 3.0h; S5: charge at a constant current of 0.8C2A for 2.0h; S6: Charge for 1.0h at a constant voltage of 16.4V and a current limit of 1.0C2A; S7: Discharge at a constant current of 1.0C2A for 30 min; S8: charge at a constant current of 0.8C2A for 1.0h; S9: Charge for 2.5h at a constant voltage of 16.6V and a current limit of 0.7C2A; S10: Discharge at a constant current of 1.0C2A for 45 min; S11: charge at a constant current of 0.8C2A for 1.0h; S12: Charge for 3.5h at a constant voltage of 16.8V and a current limit of 0.7C2A; S13-discharge at a constant current of 1.0C2A for 55 min; S14-charge at a constant current of 0.8C2A for 1.0h; S15-charge at a constant voltage of 17.0V and a current limit of 0.7C2A for 4.5h; S16-discharge at a constant current of 1.0C2A for 1.0h 10min; S17: Charge at a constant current of 0.8C2A for 3.0h; S18: Charge at a constant current of 0.7C2A for 3.0h; S19-charge at a constant voltage of 17.2V and a current limit of 0.6C2A for 3.5h; S20: let stand for 10 minutes, and then vacuumize for 5 to 10 seconds; S21: Discharge at a constant current of 1.0C2A for 1.0h 40min; S22: Discharge at a constant current of 1.0C2A to 10.0V / pcs; S23: charge at a constant current of 0.8C2A for 2.5h; S24-charge at a constant current of 0.7C2A for 1.0h; S25-charge at constant current 0.6C2A for 1.0h; S26-charge at a constant current of 0.24C2A for 30 min; S27-charge at a constant current of 0.05C2A for 3.0h; S28-End.

8. The preparation method according to claim 7, characterized in that: In steps S6, S9, S12, S15, and S19, voltage limiting control is performed, and the voltages are 16.4V, 16.6V, 16.8V, 17.0V, and 17.2V, respectively.

9. The preparation method according to claim 7, characterized in that: Step S22 is the capacity discharge test. The voltage value is divided into 6 levels, 0 to 5, as the first grouping of the battery online capacity test. 10.0V≤0 gear<10.15V; 10.15V≤1st gear<10.30V; 10.30V≤2nd gear<10.45V; 10.45V≤3rd gear<10.60V; 10.60V≤4th gear<10.75V; 10.75V≤5th gear<10.90V.

10. The preparation method according to claim 7, characterized in that: After charging in step S27, the voltage value is between 16.30 and 16.60 V to extract free acid.

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