Container formation charging method for traction valve control lead storage battery

Abstract

The invention discloses an internal formation charging method for a traction valve control lead storage battery, and relates to the technical field of traction lead storage batteries. The internal formation charging method for the lead storage battery provided by the invention is divided into 33 charging and discharging stages, the formation charging time is less than 70 hours, each period comprises 12 charging and 11 discharging, one time of standing and one time of capacity checking and matching, and the electric quantity charged each time is greater than the electric quantity discharged subsequently. According to the method, the charging current is moderate in the process, the charging and discharging cycle frequency and intensity in the charging process are reasonably designed, the concentration polarization phenomenon can be effectively reduced, damage to crystal structures of active substances on polar plates is reduced, and the cycle service life of the lead storage battery can be prolonged by 21%-36%. According to the detection of GB / T7403.1-2018 national standard regulation, the cycle life of the lead storage battery prepared by the method is more than 850 times, and the first discharge capacity of the lead storage battery is not less than 90%.

Description

Technical Field

[0001] The invention relates to the technical field of lead-acid batteries for traction, and in particular to an internal formation charging method for a valve-controlled lead-acid battery for traction. Background Art

[0002] Compared with the external formation process, the internal formation of lead-acid batteries has many advantages. Its process flow simplifies the processes of plate washing, drying, battery supplementary charging, and plate loading, welding, and plate removal in the tank formation. It saves a lot of energy (pure water, acid, electricity and other energy), man-hours, occupies a small area, and the plates are charged inside the battery, which discharges less acid mist. There is no need to purchase formation tank equipment and acid mist prevention equipment, and the battery cost can be reduced to a certain extent. The plates are not easily contaminated by impurities, which can reduce the self-discharge of the battery, improve the consistency of the battery, and extend the battery life. In addition, the internal formation of the battery reduces the discharge of wastewater and waste gas, thereby reducing environmental pollution. Therefore, the internal formation of batteries has been widely promoted. However, the internal formation charging process of valve-regulated lead-acid batteries has strict requirements. In order to improve the utilization rate of sites and facilities, some manufacturers shorten the formation charging time and increase the charging current. When the cooling system is not guaranteed, the lead-acid battery overheats and causes irreversible internal damage. The cycle life of the battery is greatly reduced.

[0003] The patent application with publication number CN104134826A discloses an eight-charge and seven-discharge internalization charging process for a 20AH lead-acid battery, comprising: step one: first charging: first charging the battery with a current of 3.0A for 3 hours, and then charging the battery with a current of 5.0A for 7.5 hours; step two: first discharging: discharging the battery with a current of 6.0A for 0.5 hours; step three: second charging: charging the battery with a current of 5.0A for 2.5 hours; step four: second discharging: discharging the battery with a current of 6.0A for 1 hour; step five: third charging: charging the battery with a current of 5.0A for 3 hours; step six: third discharging: discharging the battery with a current of 8.0A for 1 hour; step seven: fourth charging: charging the battery with a current of 5.0A for 3.5 hours; step eight: fourth discharging: discharging the battery with a current of 8.0A for 1 hour; step nine: fifth charging: discharging the battery with a current of 5.0A for 1 hour. A current is used to charge the battery for 4 hours; Step 10: The fifth discharge: the battery is discharged at a current of 8.0A for 1h15min; Step 11: The sixth charge: the battery is charged at a current of 5.0A for 4 hours; Step 12: The sixth discharge: the battery is discharged at a current of 8.0A for 1h15min; Step 13: The seventh charge: first charge the battery at a current of 5.0A for 6 hours, and then charge the battery at a current of 3A for 4 hours; Step 14: The seventh discharge: discharge the battery at a current of 10.0A for 1h50min; Step 15: The eighth charge: first charge the battery at a current of 5.0A for 6 hours, then charge the battery at a current of 2.0A for 5.5 hours, then charge the battery at a current of 1A for 3 hours, and finally discharge the battery at a current of 0.2A for 2.5 hours; Step 16: After waiting for 3 hours, the battery is acid-extracted at a current of 0.4A for 5 hours. This method has a large charging current (0.4C) and a long charging time (70 hours), which can easily damage the lead-acid battery.

[0004] The current internal charging process of valve-regulated lead-acid batteries for traction has a charging time of 70-85 hours, with low internal charging efficiency; the charging rate reaches 7.6-10.5 times. The cycle life of traction batteries is generally around 700 times. Summary of the invention

[0005] Based on the problem of short cycle life of valve-regulated lead-acid batteries for traction in the prior art, the present invention provides an internal formation charging method for valve-regulated lead-acid batteries for traction, which can increase the cycle life of the lead-acid batteries by 21% to 36%.

[0006] The invention provides an optimal ratio of current intensity and formation time by long-term tracking of the relationship between the charging quantity and the hydrogen evolution electromotive force of the battery, reduces the occurrence of battery electrolysis water, controls the process water temperature, enables the pole plate to be fully formed, and forms an optimized internal formation process of the traction lead-acid battery.

[0007] In this technical solution, C5 refers to the 5-hour rate rated capacity, I5 refers to the 5-hour rate discharge current, I5=0.2C5, and the unit is ampere (A). When current flows through the battery, both the positive and negative electrodes undergo chemical reactions. The consumption of reactants makes the ion concentration on the surface and near the positive and negative plates somewhat different from the concentration in the original solution. The phenomenon of potential difference caused by this is called concentration polarization. Concentration polarization greatly hinders the charging of the battery. The theoretical amount of electricity per kilogram of active material in the positive and negative plates is basically between 223.9A•h and 225.4A•h. Due to the existence of side reactions in the formation and charging process of the green plates, the amount of electricity formed by the plates is much higher than the theoretical value. The actual amount of electricity formed is 1.9~3.2 times the theoretical value. This value depends on the thickness of the plate, the composition of the solidified lead paste, the particle size of the components of different phases, and the constant current and constant voltage methods of charging and formation.

[0008] The internal formation charging method of the lead-acid battery provided by the present invention is divided into 33 charging and discharging stages, and the formation charging time is less than 70 hours, including 12 charging and 11 discharging, 1 static placement and 1 capacity inspection and matching, and the amount of electricity charged each time is greater than the amount of electricity discharged subsequently, wherein the maximum charging current is 1.36 I5 (0.30C5), and the minimum charging current is 0.01~0.015I5 (0.002~0.003C5).

[0009] In the formation process, the formation current is an important process parameter. The size of the formation current has a great influence on the formation efficiency, formation cost and formation quality of the plate. If the formation current is too large, it will lead to increased polarization of the electrode, too high a voltage rise, and too fast gas precipitation. On the one hand, it may cause the active material of the plate to become loose or fall off, and on the other hand, it will reduce the current efficiency and increase energy consumption. At the same time, the temperature rise of the electrolyte will also become faster. When the formation current is too small, the current density is reduced, and the formation charging power is insufficient, which will lead to insufficient formation of the plate.

[0010] A method for internal formation charging of a valve-regulated lead-acid battery for traction of the present invention comprises the following steps: (1) Pre-charge stage S1: Charge at a current of 0.08~0.12 C5A for 0.5h, S2: Discharge at a current of 0.10~0.20 C5A for 0.05h; (2) Three-gradient current boost charging S3: Charge at a current of 0.10~0.15 C5A for 0.5h, S4: Charge at a current of 0.15~0.18 C5A for 3~3.5h, S5: charge at a current of 0.18~0.20 C5A for 4h; (3) Five cycles of charge and discharge S6: Discharge at a current of 0.10~0.15 C5A for 0.1h, S7: Charge at a current of 0.18~0.20 C5A for 4h, S8: Discharge at a current of 0.10~0.15 C5A for 0.5h, S9: Charge at a current of 0.18~0.20 C5A for 4h, S10: Discharge at a current of 0.20~0.25 C5A for 0.5h, S11: Charge at a current of 0.18~0.20 C5A for 4h, S12: Discharge at a current of 0.20~0.25 C5A for 0.5h, S13: Charge at a current of 0.18~0.20 C5A for 4~5h, S14: Discharge at a current of 0.20~0.25 C5A for 0.5h, S15: Charge at a current of 0.18~0.20 C5A for 4~5h, S16: Discharge at a current of 0.20~0.25 C5A for 0.5h; (4) Four-gradient falling current charging and discharging S17: Charge at a current of 0.15~0.18 C5A for 3h, S18: Discharge at a current of 0.20~0.25 C5A for 0.5h, S19: Charge at a current of 0.10~0.15 C5A for 2h, S20: Discharge at a current of 0.20~0.25 C5A for 0.2h, S21: Charge at a current of 0.08~0.12 C5A for 3h, S22: Discharge at a current of 0.20~0.25 C5A for 0.1h, S23: charge at a current of 0.03~0.05 C5A for 3h; (5) Let stand S24: let stand for 1 hour; (6) Capacity test set S25: Discharge at 0.20 C5A for 4h 58min, S26: Discharge at a current of 0.20 C5A for 0-20 min, and classify according to the termination voltage; (7) Gradient descent constant current and voltage limiting charging S27: Charge at a current of 0.25~0.30 C5A for 3h, S28: Charge at 0.19~0.22 C5A for 2~3h, S29: Charge at 0.15~0.18 C5A for 2~3h, S30: Charge at a current of 0.10~0.15 C5A for 1~3h, S31: Charge at a current of 0.06~0.08 C5A for 1h, S32: Charge at a current of 0.03~0.04 C5A for 2.5~3h; (8) Float charge and acid extraction S33: Charge for 4 hours at a current of 0.002~0.003 C5A to extract acid, and stop charging after the acid extraction is completed.

[0011] Among them, in step (1), at the beginning, the internal resistance between the grid and the active material is large, the conductivity of the battery plate is very poor, and the internal resistance of the battery is large. A small current is used to form active materials with good conductivity between the positive and negative grids and the corrosion layer, and between the corrosion layer and the active material. If the current is too large, on the one hand, an oxide layer will be formed between the grid and the corrosion layer, increasing the internal resistance between the grid and the active material; on the other hand, too large a current will cause severe heat generation, increase the stress between the grid and the active material, and increase the risk of the active material detaching from the grid in the later cycle.

[0012] Step (2): The lead-acid battery is charged with a gradient current three times, which increases the battery's acceptable capacity and greatly reduces the damage to the plate caused by a large current. After the gradient current charging, the cycle charge and discharge of step (3) is performed to fully reduce or even eliminate the polarization of the battery during the electrochemical formation process.

[0013] Step (3): Cyclic charge and discharge: One charge and one discharge is a charge and discharge cycle. In each charge and discharge cycle, the charge amount is greater than the discharge amount. When the battery reaches a certain voltage (close to the voltage of the battery gas evolution point), it starts to discharge, and the cycle discharge depth gradually increases with the increase of the charge amount. After five charge and discharge cycles, proceed to the next step.

[0014] Step (4): Gradient current reduction charging can preferentially reduce the damage to the battery caused by the current in the later stage of charging.

[0015] Step (5): Leaving the battery to rest can help the chemical reaction inside the battery reach equilibrium, improve charging efficiency and reduce battery polarization. The hydrogen and oxygen produced by the electrochemical reaction inside the battery have time to recombine and be absorbed, thereby reducing the internal pressure of the battery, allowing the next round of constant current charging to proceed more smoothly and allowing the battery to absorb more electricity.

[0016] Step (6): Capacity detection and battery matching (battery matching consistency requirements) In step S26, the batteries are classified according to the termination voltage (12V series batteries): 0 gear: 10.10~10.27V; 1st gear: 10.28~10.43V; 2nd gear: 10.44~10.58V; 3rd gear: 10.59~10.72V; 4th gear: 10.73~10.84V; 5th gear: 10.85~10.95V; 6th gear: 10.96~11.05V; 7th gear: 11.06~11.14V; 8th gear: 11.15~11.22V; 9th gear: 11.23~11.28V; 10th gear: 11.29~11.33V; After classification, grouping is carried out according to the open circuit voltage ≥13.05V and the open circuit voltage difference ≤0.02V.

[0017] Preferably, the battery with a termination voltage less than 10.10V or a termination voltage greater than 11.33V returns to step S17 for recharging, re-grading and grouping.

[0018] Preferably, during the internalization charging process, the charging current fluctuation is controlled within ±0.3%A, and the discharging current fluctuation is controlled within ±0.3%A.

[0019] Preferably, the internalized charge capacity is 6.70 to 7.20 times the rated capacity of the lead-acid battery.

[0020] Preferably, the total time from internalization to charging is 64 to 70 hours.

[0021] Preferably, the voltage in step (7) is limited to 16.1 V. After the inspection in step (7) is completed, charging is performed with a constant current and voltage limit (16.1 V) to increase the depth of internalization, fully activate the battery potential, and extend the battery life.

[0022] Preferably, the internal formation charging method for valve-regulated lead-acid batteries for traction of the present invention further comprises acid addition: vacuum acid filling of the lead-acid battery, transferring the internal formation lead-acid battery filled with formation electrolyte into a cooling water tank with cooling circulating water within 10 to 15 minutes, connecting the lead-acid battery to a charger in preparation for internal formation, and starting internal formation charging when the temperature of the lead-acid battery drops below 40° C.

[0023] Preferably, the concentration of the formation electrolyte at 25° C. is 1.195 g±0.005 g / mL.

[0024] As the concentration of sulfuric acid electrolyte in lead-acid batteries increases, the self-discharge of the battery will be significantly enhanced, and the corrosion of the grid will also be accelerated, which will accelerate the shedding of the active material lead dioxide on the plate. As the concentration of sulfuric acid electrolyte in lead-acid batteries increases, the number of battery cycles will eventually decrease. The high concentration of sulfuric acid electrolyte in lead-acid batteries will increase the production of lead sulfate in the unformed plates, and the increase of poorly conductive lead sulfate will lead to a decrease in the relative amount of current, thereby reducing the formation efficiency.

[0025] Preferably, during the internal formation charging process, the internal temperature of the lead-acid battery is maintained at ≤55°C; When the internal temperature of the lead-acid battery is greater than 55°C, stop charging and cool down; In the cooling water tank, the cooling circulating water temperature is controlled at 28~40℃.

[0026] High temperature can easily degrade the additives of the negative plate, loosen the positive plate, increase the particle size of the active material, reduce the reaction area, and affect the battery capacity and life. When the temperature is ≤55℃, for example, when the temperature is between 30-40℃, the use time of the lead-acid battery will be extended by 8 to 10 cycles if the temperature increases by 1-2℃; when the temperature is between 40-50℃, the use time of the lead-acid battery will be extended by 30 cycles if the temperature increases by 1-2℃; when the temperature is greater than 55℃, it will affect the service life of the battery. Through the circulation and heat exchange of water in the internalization water bath, the temperature inside the lead-acid battery during the internalization charging process is reduced to avoid overheating during the charging process that causes a decrease in the service life of the lead-acid battery.

[0027] The above charging current and charging time are reasonably designed, which not only reduces the amount of electricity used for electrolyzing water during the charging process, but also reduces the consumption of electricity by the single-piece polar plate of the lead-acid battery, thereby reducing energy consumption.

[0028] Beneficial effects of the present invention: The internal formation charging method of the lead-acid battery provided by the present invention is divided into 33 charging and discharging stages, and the formation charging time is less than 70 hours, including 12 charging and 11 discharging, 1 static and 1 capacity inspection, and the amount of electricity charged each time is greater than the amount of electricity discharged subsequently. The charging current in the process of the method of the present invention is moderate, and the charge and discharge cycle frequency and intensity in the charging process are reasonably designed, which can effectively reduce the concentration polarization phenomenon, reduce the damage to the crystal structure of the active material on the plate, and extend the cycle life of the lead-acid battery by 21% to 36%. According to the national standard GB / T7403.1-2018, the cycle life of the lead-acid battery of the method of the present invention is greater than 850 times, and the first discharge capacity of the lead-acid battery is not less than 90%. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments.

[0030] Example 1

[0031] Take the traction valve-regulated lead-acid battery 6-DFP-110AH as an example, with a rated capacity of 110Ah. The number of single plates is +5 / -6 (indicates that the number of positive plates is 5 and the number of negative plates is 6), the amount of lead paste for the positive plate is 310g / piece, the amount of lead paste for the negative plate is 218g / piece, the amount of acid per cell is 1210±8g, the lead-acid battery is installed with an acid adding pot for acid addition, a temperature sensor is inserted into the acid adding pot, and 2℃ acid (1.195g±0.005g / mL, 25℃) is added. The amount of acid per cell is 1210±8g. When the internal temperature of the battery is 30℃ after 15 minutes of acid addition, 17 6-DFP-110AH traction vehicle batteries are connected in series with the positive and negative poles of the battery connected end to end and charged according to the formation process in Table 1 below.

[0032] Table 1

[0033] After the S26 stage, the voltage is divided into different grades according to the termination voltage. The grade information is shown in Table 2: Table 2

[0034] The termination voltage is less than 10.10V for low gear, and the termination voltage is greater than 11.33V for high gear. This type of battery is discarded, and recharged in series according to the charging method in Table 1 (starting from step S17), and then graded again according to Table 2 above.

[0035] After grading, capacity detection and grouping are carried out. Grouping is carried out when the open circuit voltage is ≥13.05V and the open circuit voltage difference is ≤0.02V. The grouping information is shown in Table 3.

[0036] Table 3

[0037] Example 2 Take the traction valve-regulated lead-acid battery 6-DFP-110AH as an example, with a rated capacity of 110Ah. The number of single plates is +5 / -6, the amount of lead paste for the positive plate is 310g / piece, the amount of lead paste for the negative plate is 218g / piece, and the amount of acid per cell is 1210±8g. The lead-acid battery is installed with an acid adding pot for acid addition. A temperature sensor is inserted into the acid adding pot, and 9℃ acid (1.195g±0.005g / mL, 25℃) is added. When the internal temperature of the battery is 50℃ after 25 minutes of acid addition, 17 6-DFP-110AH traction vehicle batteries are connected in series in each way with the positive and negative poles of the battery connected end to end and charged according to the formation process in Table 4 below.

[0038] Table 4

[0039] Example 3 (60 minutes after adding acid, the internal temperature of the battery was measured to be 56°C, and the early battery formation temperature was too high) Take the traction valve-regulated lead-acid battery 6-DFP-110AH as an example, with a rated capacity of 110Ah. The number of single plates is +5 / -6, the amount of lead paste for the positive plate is 310g / piece, the amount of lead paste for the negative plate is 218g / piece, the amount of acid per cell is 1210±8g, the lead-acid battery is installed with an acid adding pot for acid addition, a temperature sensor is inserted into the acid adding pot, and (1.195g±0.005g / mL, 25°C) acid is added. When the internal temperature of the battery is measured to be 56°C after 60 minutes of acid addition, 17 6-DFP-110AH traction vehicle batteries are connected in series in each circuit with the positive and negative electrodes of the battery connected end to end and charged according to the formation process in Table 4 (the charging process is the same as that in Example 2).

[0040] Take the traction valve-regulated lead-acid battery 6-DFP-110AH as an example, with a rated capacity of 110Ah. The number of single plates is +5 / -6, the amount of lead paste for the positive plate is 310g / piece, the amount of lead paste for the negative plate is 218g / piece, and the amount of acid per cell is 1210±8g. The lead-acid battery is installed with an acid adding pot for acid addition. A temperature sensor is inserted into the acid adding pot, and 9℃ acid (1.195g±0.005g / mL, 25℃) is added. When the internal temperature of the battery is 50℃ after 25 minutes of acid addition, 17 6-DFP-110AH traction vehicle batteries are connected in series in each circuit with the positive and negative poles of the battery connected end to end and charged according to the formation process in Table 5 below.

[0041] Table 5

[0042] Comparative Example 1: Charging method using GB / T7403.1-2018 standard 5.3.2.2 a Take the traction valve-regulated lead-acid battery 6-DFP-110AH as an example, with a rated capacity of 110Ah. The number of single plates is +5 / -6, the amount of lead paste for the positive plate is 310g / piece, the amount of lead paste for the negative plate is 218g / piece, the amount of acid per cell is 1210±8g, the lead-acid battery is installed with an acid adding pot for acid addition, a temperature sensor is inserted into the acid adding pot, and 9°C acid (1.195g±0.005g / mL, 25°C) is added. When the internal temperature of the battery is 50°C after 25 minutes of acid addition, 17 6-DFP-110AH traction vehicle batteries are connected in series in each way with the positive and negative electrodes of the battery connected end to end and charged according to the formation process in Table 6 (steps 1 to 26 are the same as those in Example 2).

[0043] Table 6

[0044] Comparative Example 2: The commonly used eight-charge and seven-discharge internal charging method Take the traction valve-regulated lead-acid battery 6-DFP-110AH as an example, with a rated capacity of 110Ah. The number of single plates is +5 / -6, the amount of lead paste for the positive plate is 310g / piece, the amount of lead paste for the negative plate is 218g / piece, and the amount of acid per cell is 1210±8g. The lead-acid battery is installed with an acid adding pot for acid addition. A temperature sensor is inserted into the acid adding pot, and 9℃ acid (1.195g±0.005g / mL, 25℃) is added. When the internal temperature of the battery is 50℃ after 25 minutes of acid addition, 17 6-DFP-110AH traction vehicle batteries are connected in series in each circuit with the positive and negative poles of the battery connected end to end and charged according to the formation process in Table 7 below.

[0045] Table 7

[0046] Test example 1: According to GB / T7403.1-2018 standard 6.5.2.2 valve-regulated battery charging and discharging process, the above examples were subjected to cycle endurance tests. The test results are shown in Table 8 below: Table 8

[0047] According to each charging process, the various indicators are statistically shown in Table 9 below: Table 9

[0048] In summary; the charging method of the present invention (especially Example 2) can shorten the charging time by nearly 10 hours, reduce the charging amount by 15% to 40%, improve the formation efficiency, reduce energy consumption, and save social resources. The battery detection performance cycle endurance test is also better than the comparative formation process. Because the formation process adopts a step-by-step progressive charging design, it effectively buffers the electrochemical polarization phenomenon of the charging process, making the active material conversion more uniform and thorough, which is beneficial to extending the service life of the battery. Because no large current is used during the entire formation process, the temperature of the formation process is controlled below 50°C, which effectively protects the high-temperature volatilization of organic additives in the negative electrode lead paste, which is beneficial to the maintenance of the battery cycle performance.

Claims

1. A method for internal formation charging of a valve-regulated lead-acid battery for traction, characterized in that: The following steps are involved: (1) Pre-charge stage S1: Charge at a current of 0.08~0.12 C5A for 0.5h, S2: Discharge at a current of 0.10~0.20 C5A for 0.05h; (2) Three-gradient current boost charging S3: Charge at a current of 0.10~0.15 C5A for 0.5h, S4: Charge at a current of 0.15~0.18 C5A for 3~3.5h, S5: charge at a current of 0.18~0.20 C5A for 4h; (3) Five cycles of charge and discharge S6: Discharge at a current of 0.10~0.15 C5A for 0.1h, S7: Charge at a current of 0.18~0.20 C5A for 4h, S8: Discharge at a current of 0.10~0.15 C5A for 0.5h, S9: Charge at a current of 0.18~0.20 C5A for 4h, S10: Discharge at a current of 0.20~0.25 C5A for 0.5h, S11: Charge at a current of 0.18~0.20 C5A for 4h, S12: Discharge at a current of 0.20~0.25 C5A for 0.5h, S13: Charge at a current of 0.18~0.20 C5A for 4~5h, S14: Discharge at a current of 0.20~0.25 C5A for 0.5h, S15: Charge at a current of 0.18~0.20 C5A for 4~5h, S16: Discharge at a current of 0.20~0.25 C5A for 0.5h; (4) Four-gradient falling current charging and discharging S17: Charge at a current of 0.15~0.18 C5A for 3h, S18: Discharge at a current of 0.20~0.25 C5A for 0.5h, S19: Charge at a current of 0.10~0.15 C5A for 2h, S20: Discharge at a current of 0.20~0.25 C5A for 0.2h, S21: Charge at a current of 0.08~0.12 C5A for 3h, S22: Discharge at a current of 0.20~0.25 C5A for 0.1h, S23: charge at a current of 0.03~0.05 C5A for 3h; (5) Let stand S24: let stand for 1 hour; (6) Capacity test set S25: Discharge at 0.20 C5A for 4h 58min, S26: Discharge at a current of 0.20 C5A for 0-20 min, and classify according to the termination voltage; (7) Gradient descent constant current and voltage limiting charging S27: Charge at a current of 0.25~0.30 C5A for 3h, S28: Charge at 0.19~0.22 C5A for 2~3h, S29: Charge at 0.15~0.18 C5A for 2~3h, S30: Charge at a current of 0.10~0.15 C5A for 1~3h, S31: Charge at a current of 0.06~0.08 C5A for 1h, S32: Charge at a current of 0.03~0.04 C5A for 2.5~3h; (8) Float charge and acid extraction S33: Charge for 4 hours at a current of 0.002~0.003 C5A to extract acid, and stop charging after the acid extraction is completed.

2. The internal formation charging method for valve-regulated lead-acid battery for traction according to claim 1, characterized in that: In step S26, the grading is performed according to the termination voltage: 0 gear: 10.10~10.27V; 1st gear: 10.28~10.43V; 2nd gear: 10.44~10.58V; 3rd gear: 10.59~10.72V; 4th gear: 10.73~10.84V; 5th gear: 10.85~10.95V; 6th gear: 10.96~11.05V; 7th gear: 11.06~11.14V; 8th gear: 11.15~11.22V; 9th gear: 11.23~11.28V; 10th gear: 11.29~11.33V; After classification, grouping is carried out according to the open circuit voltage ≥13.05V and the open circuit voltage difference ≤0.02V.

3. The internal formation charging method for a valve-regulated lead-acid battery for traction according to claim 2, characterized in that: Batteries with a final voltage of less than 10.10 V or a final voltage of more than 11.33 V return to step S17 for recharging, reclassification and grouping.

4. The internal formation charging method for valve-regulated lead-acid battery for traction according to claim 1, characterized in that: During the internalization charging process, the charging current fluctuation is controlled within ±0.3%A, and the discharge current fluctuation is controlled within ±0.3%A.

5. The internal formation charging method of a valve-regulated lead-acid battery for traction according to claim 1, characterized in that: The internalized charge capacity is 6.70~7.20 times the rated capacity of the lead-acid battery.

6. The internal formation charging method for valve-regulated lead-acid battery for traction according to claim 1, characterized in that: The total time from internalization to charging is 64 to 70 hours.

7. The internal formation charging method of a valve-regulated lead-acid battery for traction according to claim 1, characterized in that: In step (7), the voltage is limited to 16.1V.

8. The internal formation charging method for valve-regulated lead-acid battery for traction according to claim 1, characterized in that: It also includes acid adding: the lead-acid battery is vacuum filled with acid, the internalized lead-acid battery filled with electrolyte is transferred into a cooling water tank with cooling circulating water within 10 to 15 minutes, the lead-acid battery is connected to the charger and prepared for internalization, and when the temperature of the lead-acid battery drops below 40°C, the internalization charging is started.

9. The internal formation charging method for valve-regulated lead-acid battery for traction according to claim 8, characterized in that: The concentration of the formation electrolyte at 25° C. is 1.195 g±0.005 g / mL.

10. The internal formation charging method for valve-regulated lead-acid battery for traction according to claim 8, characterized in that: During the internal formation charging process, keep the internal temperature of the lead-acid battery ≤ 55℃; When the internal temperature of the lead-acid battery is greater than 55°C, stop charging and cool down; In the cooling water tank, the cooling circulating water temperature is controlled at 28~40℃.

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