Positive and negative pulse formation process for prolonging floating charge life of medium-and-large-density lead storage battery

Abstract

The invention discloses a positive and negative pulse formation process for prolonging the floating charge life of a medium-large-density lead storage battery, and belongs to the technical field of lead-acid storage battery formation. The formation process comprises the following steps: standing; carrying out constant-current charging; primary pulse charging and discharging; discharging at constant current; carrying out secondary pulse charging and discharging; discharging at constant current; carrying out tertiary pulse charging and discharging; carrying out constant-current charging; judging capacity; carrying out fourth pulse charging and discharging; and constant-current charging is stopped. The specific parameters of the positive and negative pulse charging and discharging process are as follows: the current rising slope is 90-110 A / s, the amplitude of the positive pulse is 0.30-0.50 C, and the width is 3-6 s; the current drop slope is 90-110A / s, the amplitude of the negative pulse is 0.20-0.40 C, and the width of the negative pulse is 1-3s. By utilizing a pulse formation process, electrochemical corrosion of the positive grid can be avoided, and the floating charge life of the battery is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid battery formation, and in particular relates to a positive and negative pulse formation process for improving the floating charge life of medium and large-density lead-acid batteries. Background Art

[0002] The formation of lead-acid batteries refers to the process of converting the plates into positive and negative plates with electrochemical properties by using chemical and electrochemical reactions. Although the plates before formation are divided into positive and negative poles in terms of plate structure, process additives, etc., the main components of the lead paste of the plates are the same, which are lead oxide, metallic lead, lead sulfate and other substances. The plates lack the positive active material lead dioxide and the negative active material sponge lead required for the electrochemical reaction of lead-acid batteries, so they are not the positive and negative plates of lead-acid batteries in the true sense. Through formation, the lead paste material on the prepared positive plate is converted into lead dioxide to form a positive plate, and the lead paste on the prepared negative plate is converted into sponge lead to form a negative plate. Therefore, formation is a key process in battery manufacturing and affects the performance of the battery.

[0003] The medium and large lead-acid battery is a sealed lead-acid battery with a capacity of usually more than 100Ah. The existing internal formation process of the medium and large lead-acid battery mainly adopts a multi-stage constant current charge and discharge process. The current in the charging and discharging stages is basically 0.1C, so the time for the medium and large battery to complete the internal formation process is mostly 5-6 days. The internal formation has become the longest process in the production of lead-acid batteries, which seriously restricts the improvement of production efficiency; and the charging and discharging steps are more than 20 steps, and the process is cumbersome and prone to errors. On the other hand, the multi-stage constant current charge and discharge internal formation process is a charging stage lasting 10-20h and then a discharge stage of 1-2h, and repeated 3-4 times. The battery constant current charging time is long, the battery concentration polarization and electrochemical polarization are obvious, the side reaction is low, the formation efficiency is high, and the battery formation voltage is high. While the positive active material of the battery is converted, the positive grid is also kept at a high potential for a long time, causing electrochemical corrosion of the positive grid. Due to the serious corrosion of the grid, the floating charge life of the battery is affected. Therefore, there is an urgent need for a positive and negative pulse formation process to improve the floating charge life of medium and large dense lead-acid batteries to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a positive and negative pulse formation process for improving the floating charge life of medium and large-sized lead-acid batteries, so as to solve the problems of low production efficiency and poor floating charge performance of medium and large-sized lead-acid batteries.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A positive and negative pulse formation process for improving the floating charge life of medium and large dense lead-acid batteries, comprising the following steps:

[0007] S1. Standing stage: add acid to the lead-acid battery, connect the positive and negative wires, and place it in a circulating water bath to stand;

[0008] S2. Constant current charging: 0.05-0.15C constant current charging for 1.5-2.5h;

[0009] S3. One pulse charge and discharge: positive and negative pulse charge and discharge 9-11h;

[0010] S4. Constant current discharge: 0.05-0.15C constant current discharge for 0.5-1.5h;

[0011] S5. Secondary pulse charge and discharge: positive and negative pulse charge and discharge 9-11h;

[0012] S6. Constant current discharge: 0.05-0.15C constant current discharge for 0.5-1.5h;

[0013] S7. Three pulse charge and discharge: positive and negative pulse charge and discharge 7-9h:

[0014] S8. Constant current charging: 0.05-0.15C constant current charging for 9-11h, standing for 0.5-1.5h;

[0015] S9. Constant current discharge (capacitance judgment): 0.05-0.15C constant current discharge 9-11h;

[0016] S10. Four pulse charge and discharge: positive and negative pulse charge and discharge for 4-6h;

[0017] S11. Constant current charging: 0.05-0.15C constant current charging for 4-7h, stop.

[0018] Furthermore, during the positive and negative pulse charging and discharging process, the current rising slope is 90-110A / s, and the current falling slope is 90-110A / s.

[0019] Furthermore, during the positive and negative pulse charging and discharging process, the amplitude of the positive pulse is 0.30-0.50C and the width is 3-6s.

[0020] Furthermore, during the positive and negative pulse charging and discharging process, the amplitude of the negative pulse is 0.20-0.40C and the width is 1-3s.

[0021] Furthermore, the tolerance judgment termination voltage is 1.8V (1.8V / cel).

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention provides a positive and negative pulse formation process for improving the floating charge life of medium and large-sized lead-acid batteries, which shortens the formation time by about half compared with a multi-stage constant current formation procedure, and effectively improves production efficiency.

[0024] 2. The present invention adopts positive and negative current pulse formation. The negative pulse can reduce the amount of gas evolution during formation, so that the electrolyte can be better diffused into the pores of the electrode plate, reducing the concentration polarization of the electrolyte during the formation process, and effectively reducing the electrochemical polarization of the positive and negative electrodes of the battery during the formation process, thereby improving the battery formation efficiency and formation effect.

[0025] 3. The positive pulse current and positive pulse width ratio adopted in the present invention firstly satisfy the conversion of the battery active material, while the negative pulse current and negative pulse width ratio reduces the positive electrode potential of the battery. The battery formation charging process not only ensures the conversion of the active material but also avoids the positive electrode grid from being continuously at a high potential. The formation process combining pulse charge and discharge with constant current charge and discharge is utilized to comprehensively improve the electrochemical corrosion phenomenon of the positive electrode grid during the formation process.

[0026] 4. The positive plate of a lead-acid battery is composed of a positive grid and lead paste (active material). The grid acts as a conductive current collector and a carrier for fixing the active material. Battery floating charge refers to the long-term uninterrupted charging of the battery at the rated Uflo floating charge voltage to maintain a standby state. The positive plate grid of the battery is prone to oxidation corrosion under continuous charging, resulting in grid growth and grid breakage, and thus battery failure. Battery formation refers to the process of converting battery lead paste into active materials through electrochemical reactions by means of charging and discharging. The positive electrode is mainly composed of Pb, PbO, 3PbO·PbSO4·H2O, PbO·PbSO4, PbSO4 and other components converted into PbO2. The formation process is accompanied by the side reaction of electrolysis of water. In the early stage of formation, the main reaction of the positive electrode is the conversion of Pb, PbO, 3PbO·PbSO4·H2O, PbO·PbSO4, PbSO4 and other components into PbO2. At this stage, the lead paste conversion efficiency is high and there are few side reactions. In the early stage of formation, the electrochemical polarization and concentration polarization are small, and the voltage platform is low. In the middle and late stages of formation, the conversion efficiency of the positive electrode active material decreases, and the side reactions are dominant, mainly H2O=2H+0; in the middle and late stages of formation, the electrochemical polarization and concentration polarization increase, the charging voltage increases, and the battery cell voltage reaches above 2.8V; at high potential, Pb is in a thermodynamically unstable state, and the Pb on the grid surface reacts with O to form PbO2. The constant current charging time of each stage of the multi-stage constant current formation process is long, and the positive electrode grid is at a high potential for a long time. The Pb on the grid surface is continuously oxidized to PbO2, which in turn deepens the corrosion of the grid. The corrosion of the grid during the formation process will cause certain defects to the grid, which is mainly manifested in the splitting of the internal grid cells, the generation of external corrosion layers and intergranular corrosion, which greatly accelerates the corrosion rate of the grid during the floating charge process of the battery and reduces the floating charge service life. The present invention adopts a positive and negative pulse formation process. The positive pulse can ensure the conversion of active substances, and the negative pulse can reduce the occurrence of side reactions. At the same time, it eliminates electrochemical polarization and concentration polarization, reduces the charging voltage, and avoids the positive electrode being at a high charging potential. The positive and negative pulse formation process can reduce the occurrence of the Pb+2O=PbO2 reaction and avoid corrosion of the grid during the formation stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Figure 1 It is a schematic diagram of the positive and negative pulse charge and discharge process settings in Example 1 of the present invention;

[0029] Figure 2 is a graph showing the voltage variation over time during the entire formation process of a 6-GFM-150 battery in Example 1 of the present invention;

[0030] Figure 3 It is a curve diagram showing the voltage change over time during the whole formation process of the 6-GFM-150 battery in Comparative Example 1 of the present invention;

[0031] Figure 4 1 is a schematic diagram comparing the high temperature accelerated floating charge life of the battery after formation in Example 1 of the present invention and Comparative Example 1;

[0032] Figure 5 This is a metallographic image of the battery grid corrosion test after formation in Example 1 of the present invention and Comparative Example 1;

[0033] Figure 5 In: (A) is the metallographic structure of the upper-vertical rib cross-section grid formed by the pulse process in Example 1; (B) is the metallographic structure of the upper-vertical rib cross-section grid formed by the conventional process in Comparative Example 1; (C) is the metallographic structure of the upper-horizontal rib cross-section grid formed by the pulse process in Example 1; (D) is the metallographic structure of the upper-horizontal rib cross-section grid formed by the conventional process in Comparative Example 1; (E) is the metallographic structure of the lower-vertical rib cross-section grid formed by the pulse process in Example 1; (F) is the metallographic structure of the lower-vertical rib cross-section grid formed by the conventional process in Comparative Example 1; (G) is the metallographic structure of the lower-horizontal rib cross-section grid formed by the pulse process in Example 1; (H) is the metallographic structure of the lower-horizontal rib cross-section grid formed by the conventional process in Comparative Example 1. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] A positive and negative pulse formation process for improving the floating charge life of medium and large dense lead-acid batteries, comprising the following steps:

[0036] S1. Standing stage: add acid to the lead-acid battery, connect the positive and negative wires, and place it in a circulating water bath to stand;

[0037] S2. Constant current charging: 0.05-0.15C constant current charging for 1.5-2.5h;

[0038] S3. One pulse charge and discharge: positive and negative pulse charge and discharge 9-11h;

[0039] S4. Constant current discharge: 0.05-0.15C constant current discharge for 0.5-1.5h;

[0040] S5. Secondary pulse charge and discharge: positive and negative pulse charge and discharge 9-11h;

[0041] S6. Constant current discharge: 0.05-0.15C constant current discharge for 0.5-1.5h;

[0042] S7. Three pulse charge and discharge: positive and negative pulse charge and discharge 7-9h:

[0043] S8. Constant current charging: 0.05-0.15C constant current charging for 9-11h, standing for 0.5-1.5h;

[0044] S9. Constant current discharge (capacitance judgment): 0.05-0.15C constant current discharge for 9-11h to 1.8V / cel;

[0045] S10. Four pulse charge and discharge: positive and negative pulse charge and discharge for 4-6h;

[0046] S11. Constant current charging: 0.05-0.15C constant current charging for 4-7h, stop.

[0047] The specific parameters of the positive and negative pulse charge and discharge process are as follows:

[0048] The current rising slope is 90-110A / s, the amplitude of the positive pulse is 0.30-0.50C, and the width is 3-6s;

[0049] The current decline slope is 90-110A / s, the amplitude of the negative pulse is 0.20-0.40C, and the width is 1-3s.

[0050] The lead-acid battery in the following embodiments and comparative examples adopts 6-GFM-150 battery.

[0051] Example 1

[0052] A positive and negative pulse formation process for improving the floating charge life of medium and large dense lead-acid batteries, comprising the following steps:

[0053] S1. Standing stage: add acid to the 6-GFM-150 battery, connect the positive and negative wires, and place it in a circulating water bath;

[0054] S2. Constant current charging: 0.1C constant current charging for 2h;

[0055] S3. One pulse charge and discharge: positive and negative pulse charge and discharge for 10h;

[0056] S4. Constant current discharge: 0.1C constant current discharge for 1h;

[0057] S5. Secondary pulse charge and discharge: positive and negative pulse charge and discharge for 10h;

[0058] S6. Constant current discharge: 0.1C constant current discharge for 1h;

[0059] S7. Three pulse charge and discharge: positive and negative pulse charge and discharge 8h:

[0060] S8. Constant current charging: 0.1C constant current charging for 10h, let stand for 1h;

[0061] S9. Constant current discharge (capacitance judgment): 0.1C constant current discharge for 10h to 1.8V / cel;

[0062] S10. Four pulse charge and discharge: positive and negative pulse charge and discharge for 4 hours;

[0063] S11. Constant current charging: 0.1C constant current charging for 6 hours, stop.

[0064] The positive and negative pulse charge and discharge process settings are as follows Figure 1 As shown, the specific parameters are as follows:

[0065] The current rising slope is 100A / s, the amplitude of the positive pulse is 0.4C, and the width is 4s;

[0066] The current falling slope is 100A / s, the amplitude of the negative pulse is 0.3C, and the width is 1s.

[0067] The curve of voltage change over time during the whole process (63h) of 6-GFM-150 battery formation is as follows Figure 2 shown.

[0068] Comparative Example 1

[0069] A conventional multi-stage medium-density lead-acid battery formation process comprises the following steps:

[0070] S1. Standing stage: add acid to the 6-GFM-150 battery, connect the positive and negative wires, and place it in a circulating water bath;

[0071] S2. Constant current charging: 0.05C constant current charging for 2h;

[0072] S3. Constant current charging: 0.1C constant current charging for 30h;

[0073] S4. Constant current discharge: 0.1C constant current discharge for 2h;

[0074] S5. Constant current charging: 0.1C constant current charging for 20h;

[0075] S6. Constant current discharge: 0.1C constant current discharge for 2h;

[0076] S7. Constant current charging: 0.1C constant current charging for 15h;

[0077] S8. Constant current discharge: 0.1C constant current discharge for 1h;

[0078] S9. Constant current charging: 0.1C constant current charging for 9h;

[0079] S10. Constant current discharge: 0.1C constant current discharge for 8h;

[0080] S11. Constant current charging: 0.1C constant current charging for 18h;

[0081] S12. Constant current charging: 0.05C constant current charging for 10h, let stand for 1h;

[0082] S13. Constant current discharge (capacitance judgment): 0.1C constant current discharge for 10h to 1.8V / cel;

[0083] S14. Constant current charging: 0.1C constant current charging for 10h;

[0084] S15. Constant current charging: 0.05C constant current charging for 10h, stop.

[0085] The total time for the conventional multi-stage formation process of the 6-GFM-150 battery is 148 hours.

[0086] The curve of voltage change over time during the whole process (148h) of 6-GFM-150 battery formation is as follows: Figure 3 shown.

[0087] Performance Test:

[0088] (I) The battery floating charge life test was performed on the batteries formed in Example 1 and Comparative Example 1:

[0089] The high temperature accelerated floating charge life test of 7.23.2 of "YD T 799-2010 Valve-controlled Sealed Lead-acid Battery (Lead-acid) for Communication" is carried out according to the following steps. The specific test method is as follows:

[0090] (1) After the battery has completed the capacity test and reached the rated value according to the method specified in 7.7 and is fully charged, it is continuously charged at Uflo voltage for 30 days in an environment of 60℃±2℃;

[0091] (2) Take out the battery, place it for 24-36 hours, and conduct a 3-hour rate capacity test in an environment of 25℃±5℃ according to the method specified in 7.7. This is considered as a test cycle, which is equivalent to a life of 1 year;

[0092] (3) Repeat (1) and (2) until the battery capacity is less than 80% of the 3h rate rated capacity and test again. End the test when it is confirmed that it is still less than 80%. The test results should meet the following requirements: The high temperature accelerated floating charge life of 12V medium-density battery is not less than 6 times, and the high temperature accelerated floating charge life of 2V large-density battery is not less than 8 times.

[0093] Test results such as Figure 4As shown, the 6-GFM-150 battery was formed twice in parallel using the formation process of Example 1, and its high-temperature accelerated float charge life was 9 times and 10 times respectively; the 6-GFM-150 battery was formed using the formation process of Comparative Example 1, and its high-temperature accelerated float charge life was 6 times; the high-temperature accelerated float charge life of the 6-GFM-150 battery using the pulse internal formation process of the present invention is increased by 3-4 times compared with that formed by the conventional process.

[0094] (II) The battery grid corrosion test was performed on the batteries formed in Example 1 and Comparative Example 1. The specific test method is as follows:

[0095] (1) Dissect the formed battery and take out the positive plate grid;

[0096] (2) Take the ribs at different parts of the grid and prepare the samples for electron microscope analysis; perform mechanical polishing and chemical etching on the sample surface;

[0097] (3) Use a metallographic microscope to observe and analyze the alloy structure, grain size, metal corrosion layer, etc. of the prepared samples at different magnifications.

[0098] Test results such as Figure 5 Shown: Figure 5 Figures (A) and (B) in the middle are the metallographic images of the upper-vertical rib cross-section grid formed by the pulse process of Example 1 and the conventional process of Comparative Example 1, respectively; Figure 5 Figures (C) and (D) in the middle are the metallographic images of the upper-cross-rib cross-section grid formed by the pulse process of Example 1 and the conventional process of Comparative Example 1, respectively; Figure 5 Figures (E) and (F) in the middle are the metallographic images of the grid in the lower part-vertical rib cross section formed by the pulse process of Example 1 and the conventional process of Comparative Example 1 respectively; Figure 5 Figures (G) and (H) in the middle are the metallographic images of the lower-cross-rib cross-section grid formed by the pulse process in Example 1 and the conventional process in Comparative Example 1, respectively.

[0099] Depend on Figure 5 It can be seen that the battery grids (A), (C), (E), and (G) on the left side adopt pulse formation, and their grains are complete, and no obvious corrosion layer is seen around the ribs; the battery grids (B), (D), (F), and (H) on the right side adopt conventional multi-stage formation process, and their grains are small and dense, and there are obvious signs of corrosion around the ribs. Using the pulse formation process of the present invention, the metallographic grains of the grid are complete, and no obvious corrosion layer is seen on the interface. The complete grain structure has higher grid strength and corrosion resistance.

[0100] The positive pulse current and positive pulse width ratio adopted in the present invention firstly satisfies the conversion of the battery active material, while the negative pulse current and negative pulse width ratio reduces the positive electrode potential during the battery charging process. The battery formation charging process not only ensures the conversion of the active material but also avoids the positive electrode grid from being continuously at a high potential, thereby reducing the electrochemical corrosion of the positive electrode grid.

[0101] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0102] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A positive and negative pulse formation process for improving the floating charge life of medium and large-sized lead-acid batteries, characterized in that: The following steps are involved: S1. Standing stage: add acid to the lead-acid battery, connect the positive and negative wires, and place it in a circulating water bath to stand; S2. Constant current charging: 0.05-0.15C constant current charging for 1.5-2.5h; S3. One pulse charge and discharge: positive and negative pulse charge and discharge 9-11h; S4. Constant current discharge: 0.05-0.15C constant current discharge for 0.5-1.5h; S5. Secondary pulse charge and discharge: positive and negative pulse charge and discharge 9-11h; S6. Constant current discharge: 0.05-0.15C constant current discharge for 0.5-1.5h; S7. Three pulse charge and discharge: positive and negative pulse charge and discharge 7-9h: S8. Constant current charging: 0.05-0.15C constant current charging for 9-11h, standing for 0.5-1.5h; S9. Capacitance judgment: 0.05-0.15C constant current discharge 9-11h; S10. Four pulse charge and discharge: positive and negative pulse charge and discharge for 4-6h; S11. Constant current charging: 0.05-0.15C constant current charging for 4-7h, stop.

2. A positive and negative pulse formation process for improving the floating charge life of medium and large-sized lead-acid batteries according to claim 1, characterized in that: During the positive and negative pulse charging and discharging process, the current rising slope is 90-110A / s, and the current falling slope is 90-110A / s.

3. A positive and negative pulse formation process for improving the floating charge life of medium and large-sized lead-acid batteries according to claim 1, characterized in that: During the positive and negative pulse charging and discharging process, the amplitude of the positive pulse is 0.30-0.50C and the width is 3-6s.

4. A positive and negative pulse formation process for improving the floating charge life of medium and large dense lead-acid batteries according to claim 1, characterized in that: During the positive and negative pulse charging and discharging process, the amplitude of the negative pulse is 0.20-0.40C and the width is 1-3s.

5. A positive and negative pulse formation process for improving the floating charge life of medium and large-sized lead-acid batteries according to claim 1, characterized in that: The capacitance judgment termination voltage is 1.8V.

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