A method for automatically controlling the temperature of a water tank in a chemical formation process

Abstract

The invention discloses a method for automatically controlling the temperature of a water tank in a formation process. The method collects the potential of the first single-cell positive electrode of a lead-acid battery and the temperature of an electrolyte at intervals during formation, and controls water circulation according to the changes in the potential and temperature, thereby realizing automatic control of the temperature of the water tank in the formation process. In this way, the limitation of water pressure on a formation workshop can be reduced, and energy consumption can be reduced scientifically and efficiently.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid battery production, and particularly relates to a method for automatically controlling the temperature of a water tank during a formation process. Background Art

[0002] During the formation and charging stage of lead-acid batteries, a large amount of heat is generated inside. The heat must be diffused to the external environment to prevent the temperature from continuing to rise, causing "injury" to the battery and resulting in quality defects.

[0003] The heat mainly comes from three parts: acid-base neutralization heat, Joule heat and electrochemical heat change of active material conversion.

[0004] Acid-base neutralization heat (Q1): It lasts throughout the formation process and is exothermic. After the battery is acidified, basic lead sulfate and sulfuric acid react rapidly to generate lead sulfate, while releasing a large amount of heat. In the early stage of formation, this part of heat is the main reason for the temperature rise of the battery.

[0005] Joule heat (Q2): It lasts throughout the formation process and is considered heat generation. When the formation starts and the power is turned on, heat will always be generated due to the ohmic resistance inside the battery. The amount of heat generated depends on the internal resistance and the formation current.

[0006] Electrochemical heat (Q3) lasts throughout the entire formation process, with both exothermic and endothermic stages. During the formation process, in the forward conversion stage of active substances, lead oxide and lead sulfate are converted into lead dioxide and lead, and water is converted into hydrogen and oxygen. These reactions are all endothermic reactions, and in the discharge stage of the formation process, these reactions become exothermic reactions, that is, the reactions occurring in different formation stages have their own impact on the total heat balance of the system (Q 总 ) have an impact.

[0007] The battery mainly dissipates heat through the side of the shell. Currently in industrial production, during the formation process, in order to control the formation temperature, water circulation in a water tank is used to achieve the purpose of cooling.

[0008] In the hot season, after the battery is filled with acid, it is first placed in a relatively low temperature cold water tank. The water temperature is usually required to be below 20°C and the standing time is more than 30 minutes. After the initial cooling, the battery flows into the formation tank. After the entire tank is filled with batteries, water is poured into the water tank. During the formation stage, the entire tank of batteries is in a water bath. The water tank is equipped with an inlet and an outlet. The water at the outlet eventually flows to the cooling tower for cooling. After the cooling is completed, it flows into the water tank through a water pump and an inlet pipe. The water temperature of the formation process is controlled by water circulation. This production method is simple in technology and relatively reliable in non-summer seasons. It is the formation method currently adopted by enterprises. Of course, there are also many problems, especially in the hot summer season:

[0009] 1. In the chemical forming workshop, the water flow rate will not be affected at the location close to the cooling tower, but at the farther location, the temperature control effect cannot meet the requirements due to the low water pressure and small water flow rate. There are obvious differences in water temperature between chemical forming racks at different locations.

[0010] 2. The same forming rack is generally divided into three layers: upper, middle and lower. The same water inlet pipe flows into the upper, middle and lower layers of the entire forming rack. The water pressure will also be different. The same forming rack, different layers, due to the difference of batteries, have to be grouped according to the same layer, resulting in some batteries cannot be grouped, so they need to be recharged;

[0011] 3. A large-scale chemical workshop needs to install several cooling towers to work continuously, requiring sufficient area in the factory to install cooling towers. At the same time, the energy consumption during the production process is also very high;

[0012] 4. Although it can reduce energy consumption by manually inspecting the water temperature in the water tank and opening the water circulation intermittently, there is often a delay, that is, the water tank temperature has exceeded the standard, and then opening the water circulation, which may cause quality problems for some batteries;

[0013] In summary: the formation process has the disadvantages of unintelligent water temperature control in the water tank, large differences in water temperature at different positions in the water tank, and high energy consumption of the water cooling system used for cooling during the production process. Summary of the invention

[0014] Based on the deficiencies in the prior art, the present invention makes improvements in the following aspects:

[0015] Q 总 = Q1+Q2+Q3

[0016] Q1 is closely related to the density and temperature of sulfuric acid added and the cooling effect of the cold water tank. In the middle and late stages of formation, heat generation is relatively slow and the heat generation is relatively small.

[0017] Q2, depends on the current and internal resistance. According to Joule's law Q=I²Rt, the effect of current on heat generation is particularly obvious. By reducing the current, the heat generation can be significantly reduced, but under the premise of the same formation charge, the formation time will be increased, the production efficiency will be reduced, and the manufacturing cost will be increased in disguise; internal resistance is related to the formation process. The increase of polarization internal resistance, especially in the high potential stage of formation, brings obvious heat. At this time, rapid water circulation is required to exchange heat to achieve the temperature control effect. This part of the heat can be controlled by the process, but:

[0018] Q3 has both endothermic and exothermic processes and is closely related to the formation process. If the temperature rise is slow or Q1+Q2 can be offset by determining the temperature rise during the endothermic stage, water circulation can be reduced, thereby reducing manufacturing costs. In the exothermic stage, the temperature rise can also be determined to achieve automatic water circulation and achieve a cooling effect.

[0019] Based on the above theory, the present invention provides a method for automatically controlling the temperature of a water tank in a formation process to realize automatic water circulation control. The specific technical scheme is as follows:

[0020] A method for automatically controlling the temperature of a water tank in a chemical formation process comprises the following steps:

[0021] (1) After the lead-acid battery is acidified, it is cooled and then flows into the formation rack. After the water tank is filled with water, the water circulation is started and the formation begins;

[0022] (2) At certain intervals, the potential of the first single-cell positive electrode of the lead-acid battery and the temperature of the electrolyte are collected during formation, and the change in potential at certain intervals is recorded as ΔV, and the change in electrolyte temperature is recorded as ΔT;

[0023] (3) When ΔV<0, ΔT<0, close the water circulation.

[0024] When ΔV<0, ΔT≥0, the water circulation is turned on, and the flow rate of the water circulation is 1 / 3~2 / 3 of the full flow rate;

[0025] When ΔV>0, the water circulation is started, and the flow rate of the water circulation is adjusted according to the collected potential, thereby realizing automatic control of the water tank temperature during the formation process.

[0026] The reference electrode and temperature sensor are placed in the first cell. For the reference electrode, a high-purity Cd rod with low temperature sensitivity is selected as the reference, and the cadmium content is ≥99.9%. For the temperature sensor, the probe is acid-resistant and corrosion-resistant.

[0027] By placing a reference electrode and a temperature sensor in the first cell, the potential of the positive electrode of the first cell (relative to Cd) and the electrolyte temperature can be collected. The battery electrolyte temperature is the most direct and rapid response to the change in the temperature rise inside the battery. Normally, the temperature of the electrolyte will not be lower than 35°C. If the temperature is continuously significantly higher than 45°C, it will cause damage to the battery.

[0028] The reason for selecting the first cell is that the battery will not be damaged; at the same time, because of the positive potential, it can be collected through the positive terminal and the reference lead, and the wiring is simple.

[0029] Specifically, in step (1), the temperature of adding acid is 0-5°C;

[0030] When cooling down, the cooling down is carried out in a cold water tank containing cold water, and the temperature of the cold water in the cold water tank does not exceed 20°C.

[0031] Preferably, in step (2), in order to ensure accuracy during the collection process, at least two lead-acid batteries are collected for each formation circuit, and abnormal points are eliminated through the data of multiple circuits.

[0032] Specifically, the positive electrode potential data of the lead-acid battery during all formations in the water tank are collected, the average value of the positive electrode potential data is taken, and for the signal points that deviate from the average value by ±5%, it is confirmed that the reference electrode for collecting the potential is damaged or the collected lead-acid battery has an abnormality, and the abnormal voltage data is eliminated;

[0033] Collect the temperature data of the lead-acid battery electrolyte in the water tank during all the formations, take the average value of the temperature data, and for the signal points that deviate from the average value by ±2°C, confirm that the temperature sensor probe that collects the temperature data is damaged or the lead-acid battery collected has an abnormality, and eliminate the abnormal temperature data.

[0034] Specifically, in step (2), when the temperature of the electrolyte is collected to be less than 35° C., the water circulation is closed.

[0035] Preferably, in step (2), the interval time is 5 minutes. According to the acquisition frequency of recording one point every 5 minutes, the on / off mode of the water circulation is adjusted according to the changes of V and T (the acquisition points are too dense, for example, one point is acquired every 1 minute, which seems to be accurate, but in fact the changes of voltage and temperature are also small fluctuations, which can easily lead to misjudgment, so a longer time is more accurate. In the experimental stage, the present invention chooses to acquire one point every 5 minutes, which is more appropriate according to the observation of data stability).

[0036] Preferably, in step (3), when the water circulates, the water flow rate at the water inlet and the water outlet is the same. Water pumps with the same pipe diameter and power can be set to achieve automatic control of the water circulation.

[0037] Preferably, in step (3), when ΔV<0, ΔT≥0, and the electrolyte temperature ≤40°C, the water circulation is started, and the flow rate of the water circulation is 1 / 3 of the full flow rate;

[0038] When ΔV<0, ΔT≥0, and the electrolyte temperature>40°C, the water circulation is started, and the flow rate of the water circulation is 1 / 2 of the full flow rate.

[0039] In the early stage of formation, a more ideal situation is: Q3 is in the endothermic stage. After the battery is cooled by water in the water cooling tank, the acid-base neutralization heat Q1 is effectively controlled, Q1+Q2<Q3, so ΔT<0. With the further penetration of sulfuric acid in the plate, Q2 also gradually increases, Q1+Q2>Q3, but the temperature rises relatively slowly. The water circulation flow rate is set to 1 / 3~2 / 3 of the full flow rate, and it does not need to be fully opened.

[0040] Preferably, in step (3), the potential of the first single cell positive electrode of the lead-acid battery during formation is recorded as V0, and when ΔV>0, the water circulation is started.

[0041] When V0≤2.0V, the water circulation flow rate is 1 / 3 of the full flow rate.

[0042] When 2.0V<V0≤2.5V, the water circulation flow rate is 2 / 3 of the full flow rate.

[0043] When 2.5V<V0, the water circulation flow rate is full flow rate.

[0044] When it is found that ΔV>0, the temperature will definitely rise. When the voltage rises to different values, the polarization internal resistance is different, and the heat generation is also different. When the voltage reaches a high value, the polarization internal resistance is the largest and the heat generation is also the highest. If temperature control is started in advance, the temperature will rise slowly and the temperature can be controlled.

[0045] And by increasing the voltage, the water temperature can be effectively controlled in advance. In this way, the limitation of water pressure on the formation workshop can be reduced, and energy consumption can be reduced scientifically and efficiently.

[0046] The present invention also provides a formation process water tank temperature automatic control system, comprising:

[0047] The acquisition module is used to acquire the potential of the first single-cell positive electrode of the lead-acid battery and the temperature of the electrolyte during formation to obtain potential data and temperature data;

[0048] A processing module is used to process the data of the acquisition module to obtain the result of controlling the water circulation;

[0049] A result output module, used to output the results obtained by the processing module;

[0050] A control module controls the opening and closing of the water circulation and the flow rate of the water circulation according to the result output module;

[0051] When processing the data from the acquisition module, the change in potential at certain time intervals is recorded as ΔV, and the temperature change of the electrolyte is recorded as ΔT;

[0052] When ΔV<0, ΔT<0, the water circulation is closed.

[0053] When ΔV<0, ΔT≥0, and the electrolyte temperature ≤40℃, start the water circulation, and the flow rate of the water circulation is 1 / 3 of the full flow rate;

[0054] When ΔV<0, ΔT≥0, and the electrolyte temperature>40℃, the water circulation is turned on, and the flow rate of the water circulation is 1 / 2 of the full flow rate;

[0055] The potential of the first single cell positive electrode of the lead-acid battery during formation is recorded as V0. When ΔV>0, the water circulation is started.

[0056] When V0≤2.0V, the water circulation flow rate is 1 / 3 of the full flow rate.

[0057] When 2.0V<V0≤2.5V, the water circulation flow rate is 2 / 3 of the full flow rate.

[0058] When 2.5V<V0, the water circulation flow rate is full flow rate.

[0059] The present invention collects the potential of the first single cell positive electrode of the lead-acid battery and the temperature of the electrolyte during formation at intervals, and controls the water circulation according to the changes of the potential and the temperature, thereby realizing automatic control of the water tank temperature during the formation process. In this way, the limitation of the water pressure on the formation workshop can be reduced, and the energy consumption can be reduced scientifically and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a graph showing changes in positive potential and electrolyte temperature in Example 1;

[0061] Figure 2 is a graph showing changes in positive potential and electrolyte temperature in Example 2;

[0062] Figure 3 is a graph showing changes in positive potential and electrolyte temperature in Example 3;

[0063] Figure 4 This is a graph showing the changes in positive potential and electrolyte temperature in Example 4. DETAILED DESCRIPTION

[0064] Example 1

[0065] Take 6-DMF-26 battery formation as an example.

[0066] Prepare sulfuric acid solution with a density of 1.242 g / cm 3 (25℃), cool to 4℃;

[0067] After the acid is added, it flows into the cold water tank for cooling. The water temperature of the cold water tank is ≤20℃;

[0068] The cold water tank is left to stand for 30 minutes. After the water cooling is completed, it flows into the formation rack. After the entire tank is filled with batteries, the water circulation is turned on and water is poured into the tank.

[0069] Each formation circuit has 18 batteries. Cd rods and temperature acquisition probes are introduced into the first cells of the first and ninth cells in each formation circuit.

[0070] Collect the positive electrode potential data of all lead-acid batteries in the whole tank, take the potential average value, and for the signal points that deviate from the average value by ±5%, confirm whether the reference electrode is damaged and whether the collected battery has any abnormality;

[0071] Collect all electrolyte temperature data of the entire tank and take the temperature average. For signal points that deviate from the average value by ±2°C, check whether the temperature probe is damaged and whether the collected battery has any abnormality.

[0072] After confirming that the collected signal is normal, the collected signal is processed to realize the water circulation control of the water tank.

[0073] Connect the power cord and start forming. The process is shown in Table 1.

[0074] Table 1

[0075]

[0076] In the initial stage of formation, within 0~2h, ΔV<0, ΔT<0, the water circulation switch is automatically closed and the water circulation is stopped;

[0077] About 2 hours later, ΔT ≥ 0, the water circulation is automatically turned on, the acid temperature (electrolyte temperature) is 36°C, T ≤ 40°C, and the water circulation flow rate is set to 1 / 3 of the full flow rate.

[0078] In the early stage of formation, it can be seen that the battery acid temperature does not exceed 40°C ( Figure 1 ).

[0079] Example 2

[0080] Take 6-DMF-26 battery formation as an example.

[0081] Prepare sulfuric acid solution with a density of 1.242 g / cm 3 (25℃), cool to 4℃;

[0082] After the acid is added, it flows into the cold water tank for cooling. The water temperature of the cold water tank is ≤20℃;

[0083] The cold water tank is left to stand for 30 minutes. After the water cooling is completed, it flows into the formation rack. After the entire tank is filled with batteries, the water circulation is turned on and water is poured into the tank.

[0084] Each formation circuit has 18 batteries. A Cd rod and a temperature acquisition probe are introduced into the first cell of the first and ninth cells of each formation circuit. After confirming that the collected signal is normal according to the method in Example 1, the collected signal is processed to realize the water circulation control of the water tank.

[0085] Connect the power line and start the formation process, the process is as shown in Table 1 in Example 1;

[0086] In the formation stage, after 17.1 hours, discharge begins, ΔV<0, ΔT<0, the water circulation switch is automatically closed, and the water circulation is stopped.

[0087] During the discharge, it can be seen that the battery acid temperature drops by about 6°C ( Figure 2 ).

[0088] Example 3

[0089] Take 6-DMF-26 battery formation as an example.

[0090] Prepare sulfuric acid solution with a density of 1.242 g / cm 3 (25℃), cool to 4℃;

[0091] After the acid is added, it flows into the cold water tank for cooling. The water temperature of the cold water tank is ≤20℃;

[0092] The cold water tank is left to stand for 30 minutes. After the water cooling is completed, it flows into the formation rack. After the entire tank is filled with batteries, the water circulation is turned on and water is poured into the tank.

[0093] Each formation circuit has 18 batteries. A Cd rod and a temperature acquisition probe are introduced into the first cell of the first and ninth cells of each formation circuit. After confirming that the collected signal is normal according to the method in Example 1, the collected signal is processed to realize the water circulation control of the water tank.

[0094] Connect the power line and start the formation process, the process is as shown in Table 1 in Example 1;

[0095] In the initial stage of formation, within 0~0.5h, ΔV<0, ΔT<0, the water circulation switch is automatically closed and the water circulation is stopped;

[0096] After about 0.5h, ΔT≥0, the water circulation is automatically turned on, the acid temperature is 36℃, T≤40℃, and the water circulation flow rate is set to 1 / 3 of the full flow rate.

[0097] After about 3.0 h, T>40°C, the water circulation flow rate is set to 2 / 3 of the full flow rate.

[0098] In the early stage of formation, it can be seen that the battery acid temperature is 40℃~42℃ ( Figure 3 ).

[0099] Example 4

[0100] Take 6-DMF-26 battery formation as an example.

[0101] Prepare sulfuric acid solution with a density of 1.242 g / cm 3 (25℃), cool to 4℃;

[0102] After the acid is added, it flows into the cold water tank for cooling. The water temperature of the cold water tank is ≤20℃;

[0103] The cold water tank is left to stand for 30 minutes. After the water cooling is completed, it flows into the formation rack. After the entire tank is filled with batteries, the water circulation is turned on and water is poured into the tank.

[0104] Each formation circuit has 18 batteries. A Cd rod and a temperature acquisition probe are introduced into the first cell of the first and ninth cells of each formation circuit. After confirming that the collected signal is normal according to the method in Example 1, the collected signal is processed to realize the water circulation control of the water tank.

[0105] Connect the power line and start the formation process, the process is as shown in Table 1 in Example 1;

[0106] During the formation process, a discharge step is set for depolarization:

[0107] In this embodiment, from 17.2h to 18.5h, in the discharge stage, ΔV < 0, ΔT < 0, the water circulation switch is automatically closed, and the water circulation is stopped;

[0108] After 18.5h, the discharge ends and the battery switches to charging.

[0109] ΔV>0, water circulation starts automatically:

[0110] In the early stage of charging, the main purpose is to complete the supplementary electricity in the discharge stage. The polarization internal resistance is small and the temperature rise is very small. At this time, because the water circulation is turned on, the temperature remains stable.

[0111] Within 5 minutes before charging, V≤2.0V, water circulation flow rate, set to 1 / 3 of the full flow rate,

[0112] During the 18.6h~20.5h period, the positive electrode potential was 2.0V<V≤2.5V, and the water circulation flow rate was set to 2 / 3 of the full flow rate.

[0113] In the first two stages (18.5 h to 20.5 h), the temperature rose slowly from 35 °C to 38 °C by controlling the water speed.

[0114] After 20.5h, V>2.5V, the water circulation flow rate is set to full flow rate, the temperature still rises rapidly in this stage, and after about 25h, the temperature reaches the highest point of 45℃, and then the temperature stabilizes at 45℃ ( Figure 4 ).

Claims

1. A method for automatically controlling the temperature of a water tank in a chemical formation process, characterized in that: The following steps are involved: (1) After the lead-acid battery is acidified, it is cooled and then flows into the formation rack. After the water tank is filled with water, the water circulation is started and the formation begins; (2) At certain intervals, the potential of the first single cell of the positive electrode of the lead-acid battery and the temperature of the electrolyte are collected during formation, and the change in potential at certain intervals is recorded as ΔV, and the change in electrolyte temperature is recorded as ΔT; (3) When ΔV<0, ΔT<0, close the water circulation. When ΔV<0, ΔT≥0, the water circulation is turned on, and the flow rate of the water circulation is 1 / 3~2 / 3 of the full flow rate; When ΔV>0, the water circulation is started, and the flow rate of the water circulation is adjusted according to the collected potential, thereby realizing automatic control of the water tank temperature during the formation process.

2. The method for automatically controlling the temperature of a water tank in a chemical formation process according to claim 1, characterized in that: In step (1), the temperature of adding acid is 0-5°C; When cooling down, the cooling down is carried out in a cold water tank containing cold water, and the temperature of the cold water in the cold water tank does not exceed 20°C.

3. The automatic temperature control method of a water tank in a chemical formation process according to claim 1, characterized in that: In step (2), data from at least two lead-acid batteries are collected for each formation circuit, and abnormal points are eliminated through data from multiple circuits.

4. The method for automatically controlling the temperature of a water tank in a chemical formation process according to claim 3, characterized in that: Collect the positive electrode potential data of the lead-acid battery in the water tank during all formations, take the average value of the positive electrode potential data, and for the signal points that deviate from the average value by ±5%, confirm that the reference electrode for collecting the potential is damaged or the collected lead-acid battery has an abnormality, and eliminate the abnormal voltage data; Collect the temperature data of the lead-acid battery electrolyte in the water tank during all the formations, take the average value of the temperature data, and for the signal points that deviate from the average value by ±2°C, confirm that the temperature sensor probe for collecting the temperature data is damaged or the lead-acid battery collected has an abnormality, and eliminate the abnormal temperature data.

5. The method for automatically controlling the temperature of a water tank in a chemical formation process according to claim 4, characterized in that: In step (2), when the temperature of the electrolyte is collected to be less than 35°C, the water circulation is closed.

6. The method for automatically controlling the temperature of a water tank in a chemical formation process according to claim 4, characterized in that: In step (2), the interval time is 5 minutes.

7. The method for automatically controlling the temperature of a water tank in a chemical formation process according to claim 1, characterized in that: In step (3), when the water circulates, the water flow rates at the water inlet and the water outlet are the same.

8. The method for automatically controlling the temperature of a water tank in a chemical formation process according to claim 7, characterized in that: In step (3), when ΔV < 0, ΔT ≥ 0, and the electrolyte temperature ≤ 40°C, the water circulation is started, and the flow rate of the water circulation is 1 / 3 of the full flow rate; When ΔV<0, ΔT≥0, and the electrolyte temperature>40°C, the water circulation is started, and the flow rate of the water circulation is 1 / 2 of the full flow rate.

9. The method for automatically controlling the temperature of a water tank in a chemical formation process according to claim 7, characterized in that: In step (3), the potential of the first single cell positive electrode of the lead-acid battery during formation is recorded as V0. When ΔV>0, the water circulation is started. When V0≤2.0V, the water circulation flow rate is 1 / 3 of the full flow rate. When 2.0V<V0≤2.5V, the water circulation flow rate is 2 / 3 of the full flow rate. When 2.5V<V0, the water circulation flow rate is full flow rate.

10. An automatic temperature control system for a water tank in a chemical formation process, characterized in that: include: The acquisition module is used to acquire the potential of the first single-cell positive electrode of the lead-acid battery and the temperature of the electrolyte during formation to obtain potential data and temperature data; A processing module is used to process the data of the acquisition module to obtain the result of controlling the water circulation; A result output module, used to output the results obtained by the processing module; A control module controls the opening and closing of the water circulation and the flow rate of the water circulation according to the result output module; When processing the data from the acquisition module, the change in potential at certain time intervals is recorded as ΔV, and the temperature change of the electrolyte is recorded as ΔT; When ΔV<0, ΔT<0, the water circulation is closed. When ΔV<0, ΔT≥0, and the electrolyte temperature ≤40℃, start the water circulation, and the flow rate of the water circulation is 1 / 3 of the full flow rate; When ΔV<0, ΔT≥0, and the electrolyte temperature>40℃, the water circulation is turned on, and the flow rate of the water circulation is 1 / 2 of the full flow rate; The potential of the first single cell positive electrode of the lead-acid battery during formation is recorded as V0. When ΔV>0, the water circulation is started. When V0≤2.0V, the water circulation flow rate is 1 / 3 of the full flow rate. When 2.0V<V0≤2.5V, the water circulation flow rate is 2 / 3 of the full flow rate. When 2.5V<V0, the water circulation flow rate is full flow rate.

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