A method of repairing a lead-acid battery

Abstract

The application discloses a kind of repair methods of lead-acid battery, belong to lead-acid battery technical field, solve the repair production efficiency low of reverse charging repair lead-acid battery method in prior art, repair success rate or low quality, etc. The method comprises the following steps: sequentially discharging, reverse polarity charging, reverse polarity discharging and normal polarity charging to lead-acid battery;In the process of step 2, 4, the highest temperature reached by the body temperature of lead-acid battery is higher than the upper limit of the temperature control range of lead-acid battery during normal use or repair;Or / and, in steps 1, 2, 3, 4, when the voltage change of lead-acid battery passes through the normal polarity overdischarge voltage interval and the reverse polarity overdischarge voltage interval of the battery, the temperature rising trend of the body temperature change of lead-acid battery is maintained. The method can be used for the repair of lead-acid battery.

Description

Technical Field

[0001] This invention belongs to the field of lead-acid battery technology, and particularly relates to a method for repairing lead-acid batteries. Background Technology

[0002] Failure modes that occur during the use of lead-acid batteries, such as positive electrode softening and / or shedding, negative electrode sulfation, electrode passivation, and liquid loss, will lead to performance degradation and even the end of the battery's lifespan.

[0003] Existing technology records that after adding a small amount of distilled water, charging and discharging lead-acid batteries to 1-100% depth and performing forward and reverse charge-discharge cycles 1-8 times can increase the average capacity of lead-acid batteries with capacity degradation or end of life by 50%-100%, with the best reaching close to the nominal capacity (rated capacity, C), thereby extending the service life of lead-acid batteries. Using a small current of 0.025-0.1C to charge and overcharge lead-acid batteries in both forward and reverse directions, while controlling the battery temperature below 50°C to prevent overheating, and undergoing a 130-hour desulfation activation process, the capacity of lead-acid batteries with capacity degradation or end of life can be restored to the rated capacity. Reversing polarity can prevent, repair, and alleviate problems such as positive electrode softening and / or detachment in lead-acid batteries. However, practical operation has revealed the following significant problems with the above-mentioned existing technologies:

[0004] First, whether it's frequent repetitive forward and reverse charging and discharging operations more than 2 times, or even up to 8 times, or in order to prevent battery overheating, avoid thermal runaway, thermal deformation, thermal overcharging or gas evolution leading to softening and shedding of active materials, thermally accelerated grid corrosion, etc., using small current for charging and discharging, and controlling the battery temperature to keep it below the upper limit of the temperature allowed for normal use or repair of lead-acid batteries, especially valve-regulated sealed lead-acid batteries (45±5℃), all of these will result in low production efficiency of repair work, heavy burden of forced cooling, high energy consumption, long repair time and high economic cost;

[0005] Secondly, in practical operation, it was found that when reverse charging causes the battery voltage to drop from 0V to a certain negative value (i.e., reverse charging, where the original positive terminal of the battery is used as the negative terminal and the original negative terminal as the positive terminal), or when forward charging causes the battery voltage to rise from 0V to a certain positive value (i.e., forward charging, where the original positive terminal of the battery is used as the positive terminal and the original negative terminal as the negative terminal), for example, for the 6-DZF-20 model valve-regulated sealed lead-acid battery, charging at a rate higher than 0.125C (C is the rated capacity at 2h rate) will cause significant or even violent heat generation and release in the battery, and the battery temperature will rise sharply and significantly. The temperature rises above room temperature and quickly reaches or exceeds the upper limit of 40±5℃ used to prevent overheating during normal use or repair of the battery. The higher the charging current, the more intense the heat generation and release, and the faster and higher the temperature rises. If the battery is cooled and controlled too forcefully at this time, not only will the aforementioned problems exist, but it will also have an adverse effect on the state of the internal electrochemical system, the electrochemical reaction process, and the electrochemical reaction results. This can easily lead to problems such as sulfation, aggravation of inconsistencies in the battery pack (a lead-acid battery pack is formed by more than one single cell connected in series and / or in parallel), and short circuits inside the battery.

[0006] Third, lead-acid batteries generally have both sulfation and softening problems. However, there is a significant difference in the reaction rate of removing softening and removing sulfation within the normal use or repair temperature control range of lead-acid batteries. Generally, the rate of removing sulfation is much slower than the rate of removing softening. This makes it difficult to solve the softening and sulfation problems of lead-acid batteries simultaneously, or the sulfation problem is not completely removed. As a result, the repair production efficiency of lead-acid batteries is low, or the success rate or performance quality of the repaired batteries is low.

[0007] Fourth, for lead-acid battery packs with capacity degradation or end of life, there are obvious inconsistencies in the liquid loss, softening, sulfation, charge acceptance, state of charge, and assembly pressure of each individual cell. Existing technologies cannot improve the inconsistency problem of battery packs or have poor effects on improving the inconsistency problem, or even worsen the degree of inconsistency.

[0008] Fifth, even if the capacity of lead-acid batteries is restored after the implementation of existing technologies, few lead-acid batteries can reach the rated capacity or above.

[0009] The aforementioned problems have long remained unresolved within the industry, and these issues are even more pronounced in small-sized lead-acid batteries. Summary of the Invention

[0010] Based on the above analysis, the present invention aims to provide a method for repairing lead-acid batteries, which solves the problems of low production efficiency, low success rate or quality of repair of lead-acid batteries, inability to improve battery pack inconsistency or poor improvement effect, or even worsening of inconsistency in the prior art.

[0011] The objective of this invention is mainly achieved through the following technical solutions:

[0012] This invention provides a method for repairing lead-acid batteries, comprising the following steps:

[0013] Step 1: Discharge the lead-acid battery so that its voltage drops from a positive value to 0V;

[0014] Step 2: Reverse charge the lead-acid battery to reduce its voltage from 0V to below n×(-1.75±0.1)V; where n is the number of individual cells connected in series in a lead-acid battery pack, and n is 1 when all individual cells in the lead-acid battery pack are connected in parallel.

[0015] When the lead-acid battery is a single lead-acid battery, n is 1;

[0016] Step 3: Perform reverse discharge on the lead-acid battery to raise its voltage from negative to 0V.

[0017] Reverse discharge, which is when the original positive terminal of the battery is used as the negative terminal and the original negative terminal is used as the positive terminal to discharge;

[0018] Step 4: Perform a forward charge on the lead-acid battery; raise the voltage of the lead-acid battery from 0V to n×(1.75±0.1)V or higher;

[0019] During steps 2 and 4, the highest temperature reached by the lead-acid battery is made higher than the upper limit of the temperature control range during normal use or repair of the lead-acid battery (generally 40±5℃); or / and, in steps 1, 2, 3, and 4, when the voltage change of the lead-acid battery passes through the over-discharge voltage range of the battery's forward polarity and the over-discharge voltage range of the reverse polarity, the temperature change of the lead-acid battery is maintained to show an upward trend.

[0020] The over-discharge voltage range of the lead-acid battery refers to the range of n×(1.75±0.1)V to 0V, and the over-discharge voltage range of the lead-acid battery refers to the range of 0V to n×(-1.75±0.1)V. Compared to the absolute value of the lower voltage limit of the lead-acid battery under normal operating conditions (n×(1.75±0.1)V), when the lead-acid battery voltage is within the aforementioned over-discharge voltage ranges, the lead-acid battery is in an over-discharge state.

[0021] The temperature change of the lead-acid battery exhibits an upward trend. This means that when analyzing the temperature change curve of the lead-acid battery as a function of voltage, the temperature on this trend line increases from the beginning to the end, or the temperature at the beginning of the trend line is lower than the temperature at the end. For example, in step 2, during reverse charging, when the lead-acid battery voltage drops from 0V to n×(-1.75±0.1)V, the temperature corresponding to the lead-acid battery at 0V is lower than the temperature corresponding to the lead-acid battery at n×(-1.75±0.1)V (or in step 4, when the lead-acid battery voltage rises from 0V to n×(1.75±0.1)V). If the temperature of a lead-acid battery with a voltage of 0V at ±0.1V is lower than the temperature of the lead-acid battery with a voltage of n×(1.75±0.1)V, then the temperature change of the lead-acid battery is considered to show an upward trend. In this upward trend, even if the battery voltage is in the reverse polarity over-discharge range or the forward polarity over-discharge range due to the excessively rapid and high temperature rise, the temperature of the lead-acid battery will reach a certain upper limit of the temperature control value, and the lead-acid battery temperature must be cooled. Thus, there is a sub-process of battery temperature decrease during the upward trend of the temperature. However, as long as the sub-process of battery temperature decrease does not affect the overall trend of the lead-acid battery temperature change showing an upward trend, it is acceptable.

[0022] Furthermore, the lead-acid battery is a lead-acid battery pack or a single lead-acid battery.

[0023] The lead-acid battery includes, but is not limited to, a sealed lead-acid battery; the lead-acid battery pack includes, but is not limited to, a lead-acid battery pack in which each individual cell is connected to the other or each individual cell is connected to the other.

[0024] Furthermore, in steps 2 and 4, when the voltage of the lead-acid battery is in the voltage regulation range of the reverse charging and forward charging, the maximum value reached by the battery body temperature or the battery body temperature is kept above room temperature or above the upper limit of the temperature control range (40±5℃) during normal use and repair of the lead-acid battery.

[0025] Or / and, when the charge / discharge voltage of a lead-acid battery is in the over-discharge range of the forward electrode, the over-discharge range of the reverse electrode, or the voltage drop range due to resistance reduction, the battery temperature drop shall not exceed 15℃;

[0026] Or / and, when the temperature change of a lead-acid battery is maintained as an upward trend, there is no process of battery temperature decreasing.

[0027] The aforementioned resistance-drop voltage range refers to the voltage range of a lead-acid battery. During charging, after the lead-acid battery voltage has just emerged from the over-discharge voltage range of the forward and reverse poles, when charged with a constant current at a certain value, the absolute value of the lead-acid battery voltage generally reaches a peak value (this value is related to the charging current). After reaching the peak value, as the constant current charging process continues, the absolute value of the lead-acid battery voltage gradually decreases from the peak value to a valley value (the valley value is lower than the peak value). The voltage range corresponding to the absolute value of the lead-acid battery voltage from the peak value to the valley value is the resistance-drop voltage range of the lead-acid battery. When the lead-acid battery is charging and the voltage is within this resistance-drop voltage range, the internal resistance of the lead-acid battery is gradually reduced as charging progresses, resulting in a significant decrease in the absolute value of the lead-acid battery voltage. When the absolute value of the battery voltage reaches the valley value, as the charging process continues, the absolute value of the lead-acid battery voltage gradually increases again. This is because the acid concentration of the electrolyte in the battery increases significantly as charging progresses.

[0028] Furthermore, when the temperature change of the lead-acid battery in steps 1, 2, 3, and 4 above shows an upward trend, the heat source causing the temperature increase of the lead-acid battery mainly comes from the heat generated by the lead-acid battery itself from the inside out during reverse charging and normal charging. That is, more than 50% of the heat source causing the temperature increase of the lead-acid battery comes from the heat generated by the lead-acid battery itself from the inside out during reverse charging and normal charging in steps 1, 2, 3, and 4.

[0029] Furthermore, in steps 2 and 4, when the lead-acid battery voltage is in the over-discharge voltage range of the forward electrode, the over-discharge voltage range of the reverse electrode, or the voltage drop range of the resistance drop, and when the temperature of the lead-acid battery body decreases, the charging current through the lead-acid battery is not zero.

[0030] Furthermore, the following steps are included between step 2 and step 3:

[0031] Cool down the lead-acid battery;

[0032] Alternatively, the lead-acid battery can be cooled in step 2, so that the lead-acid battery temperature at the start of step 3 is lower than the highest temperature reached by the lead-acid battery in step 2.

[0033] Furthermore, the following steps are included between step 2 and step 3:

[0034] Cool down the lead-acid battery;

[0035] Alternatively, the lead-acid battery can be cooled in step 2, so that the lead-acid battery temperature at the start of step 3 is lower than the highest temperature reached by the lead-acid battery in step 2.

[0036] Furthermore, liquid cooling systems and / or air cooling systems and / or natural cooling are used to cool the lead-acid batteries.

[0037] Furthermore, in step 2, reverse charging causes the battery to undergo a gas evolution reaction.

[0038] Furthermore, in at least one of steps 1 to 4 above, a mechanical action is applied to the lead-acid battery casing (generally made of plastic) to prevent or slow down deformation such as bulging of the lead-acid battery casing under high temperature and internal battery pressure. For example, a blocking force or pressure (in the opposite direction to the outward bulging direction) is applied to the plastic casing of the lead-acid battery on its easily deformable (bulging) surface to prevent or block the deformation, thereby preventing, blocking or suppressing the outward bulging deformation of the plastic casing of the lead-acid battery under high temperature and internal battery pressure.

[0039] Furthermore, before, during, and after steps 1, 2, 3, and 4, the lead-acid battery is replenished with electrolyte and / or drained:

[0040] Fluid resuscitation procedures include:

[0041] Maintain an excess of electrolyte in the lead-acid battery by adding electrolyte.

[0042] Excess electrolyte refers to a lead-acid battery having an electrolyte volume (volume or mass) greater than its initial electrolyte volume. The initial electrolyte volume refers to the electrolyte volume set or rated in the battery's product design and production plan, or the electrolyte volume of a brand-new battery product obtained after its production line.

[0043] Furthermore, the electrolyte level in a lead-acid battery is used to represent or indicate the amount of electrolyte in the battery. That is, maintaining excess electrolyte in a lead-acid battery includes keeping the actual electrolyte level higher than the initial electrolyte level of the battery. This makes it easier to identify, understand, judge, and compare the electrolyte level in actual production operations. The initial electrolyte level refers to the level corresponding to the initial electrolyte level in the lead-acid battery.

[0044] Generally, the electrolyte level in a lead-acid battery when there is excess electrolyte (excess electrolyte level) is higher than the top of the electrodes or electrode active materials in the lead-acid battery. This is especially true when the battery is fully charged or partially charged.

[0045] Furthermore, when replenishing electrolyte, if the lead-acid battery is a battery pack, the electrolyte level of each individual cell should be the same or as similar as possible.

[0046] Alternatively, the excess amount (volume or mass) of electrolyte in each individual cell of the battery pack is controlled to be within the following range: the minimum excess amount ÷ the maximum excess amount ≥ 50%; or, the maximum difference between the electrolyte levels of each individual cell is less than the distance from the average electrolyte level of each individual cell to the top of the electrode or active material; the reason for this is:

[0047] 1) Before the repair, there were obvious inconsistencies in the electrode state and electrolyte loss of each cell in the battery pack. Based on the repair practice, the control range of the difference between the electrolyte volume or level of each cell can basically ensure that it will not worsen the original inconsistency of the battery pack.

[0048] 2) During the battery pack repair process, the pre-existing inconsistencies in the battery pack can lead to inconsistent electrolyte loss in each individual cell. This results in a certain degree of dynamic change in the consistency of electrolyte volume or level among the individual cells. If the electrolyte volume or level of each individual cell is kept absolutely identical at all times during the repair process, it would impose a considerable workload (including workload and difficulty) on the actual operation. Therefore, based on the repair practice results, the control range of the difference between the electrolyte volume or level of each individual cell is determined to provide a balanced and appropriate operational reference or principle between the workload of the actual operation and the achievement of beneficial technical effects (improving battery pack consistency).

[0049] Furthermore, maintaining an excess of electrolyte in a lead-acid battery includes the following steps:

[0050] To obtain the volume or level of electrolyte in a lead-acid battery;

[0051] Determine whether the electrolyte level or volume in the lead-acid battery is below a threshold, i.e., whether it is below the original electrolyte level or volume or an excess electrolyte level. If so, add water or an aqueous liquid (e.g., sulfuric acid solution or other solutions containing additives) to the lead-acid battery up to the threshold. If not, no replenishment is required.

[0052] The liquid removal process includes:

[0053] Furthermore, the process of steps 1 to 4 above, and / or after step 4, also includes the following steps:

[0054] To obtain the volume or level of electrolyte in a lead-acid battery;

[0055] Determine whether the electrolyte level or volume in the lead-acid battery is higher than a threshold. If so, remove electrolyte from the lead-acid battery. For example, evaporation, overcharging and gas evolution, mechanical drainage, or liquid absorption can be used to reduce the electrolyte level to the threshold, i.e., the original electrolyte level or volume of the lead-acid battery, or a certain excess electrolyte level or volume. If not, no reduction is necessary.

[0056] Furthermore, the fluid replenishment and removal operations also include the following steps during or / after steps 1-4 above:

[0057] Before adding or removing electrolyte, the concentration of the electrolyte is measured and adjusted. The electrolyte concentration is adjusted to the target value by adding an aqueous solution (such as water or sulfuric acid solution) to the lead-acid battery. The target electrolyte concentration can be the original electrolyte concentration or other values. When the lead-acid battery is a battery pack, the electrolyte concentration is adjusted in the above way to make the electrolyte concentration of each cell in the battery pack consistent or tend to be consistent.

[0058] Furthermore, the aforementioned repair methods, electrolyte removal, and electrolyte replenishment operations also include opening the top of the lead-acid battery casing to the surrounding environment, allowing heat or gas inside the battery to escape. For example, the battery cover can be opened, or the battery's electrolyte inlet can be opened, or the electrolyte inlet on the top of the lead-acid battery can be connected to a container, with the container also having an opening to the external environment. The container connected to the battery's electrolyte inlet serves several purposes: first, it facilitates the release of heat and gas from inside the battery; second, the container holds excess electrolyte and allows for easy observation and assessment of the excess electrolyte level; and third, it prevents electrolyte from overflowing or splashing into the external environment during battery charging and gas evolution.

[0059] Furthermore, the electrolyte level includes the electrolyte level in the battery tank and the electrolyte level in a container connected to the battery tank.

[0060] Furthermore, the replenishment and removal of electrolyte also include: performing a vacuuming operation (e.g., vacuuming) on ​​the lead-acid battery before, during, and after replenishment and removal to remove some gas from the battery, allowing the electrolyte to enter the battery more fully. Because used batteries may have experienced overheating runaway, dehydration, or gas evolution, a certain amount of gas occupying some of the battery's pores is difficult to replace with electrolyte. Furthermore, during the repair process, when gas evolution occurs, the generated gas can easily occupy some of the battery's pores. To ensure the electrolyte fully contacts and reacts with the active materials, prevent post-repair fluid loss and thermal runaway, and improve the consistency of the battery pack, thereby increasing battery repair production efficiency, success rate, or quality, it is necessary to perform a vacuuming operation on the lead-acid battery before, during, and after replenishment and removal of electrolyte.

[0061] Furthermore, the liquid removal process also includes subjecting the lead-acid battery to at least one more charge-discharge cycle before liquid removal.

[0062] Furthermore, the depth of the at least one charge-discharge cycle is 30% or more.

[0063] Furthermore, during or after the implementation of step 4, the following step is also included: overcharging the lead-acid battery;

[0064] Overcharging refers to charging a lead-acid battery so that the voltage is not less than the battery gas evolution reaction voltage.

[0065] The overcharge operation includes: performing at least two overcharges on the lead-acid battery, discharging the battery once between the first and second overcharges, and ensuring that the amount of the second overcharge is not less than the amount of the first overcharge.

[0066] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0067] a) The lead-acid battery repair method provided by the present invention, in steps 2 and 4, makes the highest temperature reached by the lead-acid battery body temperature higher than the upper limit of the temperature control range (40±5℃) during the normal use and repair of lead-acid batteries. This can significantly accelerate the desulfation rate during reverse charging and normal charging in steps 2 and 4, reduce the reaction rate and reaction time difference between desulfation and softening problems, and make the two removal reactions more likely to be completed synchronously and thoroughly, thereby improving the repair production efficiency and repair effect of lead-acid batteries.

[0068] Specifically, the desulfurization reaction is significantly slower than the softening reaction. Coarse lead sulfate crystals have small specific surface areas, low solubility, and very low reactivity, making them generally difficult to convert and requiring a longer reaction time. Therefore, the desulfurization reaction is generally a control step to improve consistency. When the battery temperature is high, the solubility and reactivity of lead sulfate can be greatly increased, thereby accelerating the desulfurization removal rate. This allows softening and desulfurization to be removed simultaneously in a relatively shorter time. For example, if softening was originally removed in 1 hour and desulfurization in 10 hours, after increasing the temperature, softening may be removed in 0.5 hours and desulfurization in 5 hours. This shows that increasing the temperature reduces the difference or influence between softening removal and desulfurization removal, increasing synchronicity.

[0069] It should be noted that although the battery temperature in steps 2 and 4 exceeds the upper limit of the temperature control range for conventional use and repair of lead-acid batteries in the prior art, the numerous adverse consequences caused by the battery temperature exceeding the upper limit of the temperature control range in the prior art can be completely or effectively avoided or mitigated because the lead-acid battery is in the process of steps 2 and 4 at this time, and other means such as excess electrolyte and mechanical action to prevent battery casing deformation can be combined. These consequences include grid corrosion, thermal runaway, gas evolution, softening / detachment of positive electrode activity, and deformation of the battery casing under high temperature and internal pressure. This is because when high temperature and charging gas evolution occur in step 2, the battery is in a reverse polarity state. This not only does not cause softening or corrosion of the original positive electrode of the lead-acid battery, but also enhances the effect of solving and reversing the softening and / or detachment, corrosion, and passivation of the original positive electrode. Meanwhile, the softening and thermal corrosion caused by high temperature and overcharging gas evolution on the original negative electrode of the lead-acid battery can be repaired and reversed or effectively mitigated in step 4. Solution: When high temperature and overcharge gas evolution occur in step 4, on the one hand, the lead-acid battery has already undergone the process of step 2. This gives the lead-acid battery in step 4 considerable prevention and resistance to the softening and thermal corrosion damage caused by high temperature and overcharge gas evolution (in step 2, at least part of the original positive electrode active material particles are reduced to metallic lead and the particles are firmly bonded to each other). Therefore, the high temperature and overcharge gas evolution reaction conditions in step 4 are unlikely to damage the original positive electrode of the battery, or will not cause damage within a fairly wide overcharge range. On the other hand, the high temperature and overcharge gas evolution reaction conditions in step 4 are conducive to accelerating and thoroughly restoring the polarity of the active materials on each electrode of the lead-acid battery from the reverse polarity state, the over-discharge state (severe sulfation state) in the reverse polarity or symmetric polarity over-discharge range in step 2 to the polarity of the active materials on each electrode before battery repair. It is also conducive to accelerating and thoroughly removing the new sulfation problem caused by the polarity reversal process and accelerating and thoroughly restoring or activating the activity of the electrode active materials.

[0070] b) The lead-acid battery repair method provided by the present invention, in step 2, reverse charging causes the lead-acid battery voltage to drop from 0V to below n×(-1.75±0.1)V, or in step 3, forward charging causes the lead-acid battery voltage to rise from 0V to above n×(1.75±0.1)V. This prevents the battery from being in a forward or reverse over-discharge state, which is beneficial to preventing the re-sulfation of the lead-acid battery. Furthermore, when the lead-acid battery is a battery pack, experiments have shown that this also significantly improves the consistency of the lead-acid battery pack.

[0071] c) The lead-acid battery repair method provided by this invention maintains the lead-acid battery's temperature change as an upward trend during steps 1, 2, 3, and 4, and / or does not involve a temperature drop. This can prevent or alleviate problems such as battery short circuits, irreversible sulfation, and lead sulfate clogging of porous electrode pores caused by over-discharge. This is because, on the one hand, the discharge process in step 1 is an over-discharge process of the lead-acid battery, which means that more lead sulfate is generated and formed in the pores deep within the porous electrode. When the battery temperature remains unchanged or decreases during over-discharge, it will not only increase the saturation of lead sulfate in the electrolyte and cause precipitation leading to short circuits, but also cause the lead sulfate generated by over-discharge to be generated on the basis of the original lead sulfate, making the original lead sulfate larger and more irreversible. On the other hand, the lead sulfate generated by the discharge of active material deep within the electrode plate easily clogs the pores of the porous electrode plate, reducing the electrode's reaction surface area. During over-discharge, the lead-acid battery's temperature is kept constantly rising without any temperature drop. This helps increase the real-time dissolution of lead sulfate during over-discharge and regulates the solubility and saturation of the lead sulfate solution. This prevents or alleviates the precipitation of lead sulfate, thereby preventing or mitigating battery short circuits, blockage of porous electrode pores, and irreversible enlargement. This improves the success rate and efficiency of lead-acid battery repair.

[0072] Step 2, reverse charging, is a process in which the over-discharge state on the lead-acid battery electrodes occurs and is eliminated simultaneously. At the beginning of this process, the battery already contains a large amount of lead sulfate in a crystalline or dissolved state. Moreover, during the initial period of this process, the rate of lead sulfate formation is greater than the rate of lead sulfate elimination, which may further aggravate the over-discharge phenomenon. Therefore, similar to the reasons mentioned above, the overall temperature of the lead-acid battery in this reverse charging process is to rise and not fall. This is also beneficial to prevent or alleviate battery short circuits, irreversible sulfation, and lead sulfate clogging of porous electrode pores caused by over-discharge.

[0073] d) In the lead-acid battery repair method provided by the present invention, in steps 2 and 4, when the voltage of the lead-acid battery is in the voltage drop range of the reverse charging and forward charging, the maximum value reached by the battery body temperature or the battery body temperature is kept above room temperature or above the upper limit of the temperature control range (40±5℃) during the normal use and repair of lead-acid batteries is beneficial to accelerate and thoroughly remove the new sulfation problem caused by the polarity reversal process, as well as accelerate and thoroughly remove the old sulfation, softening, passivation, battery pack inconsistency and other problems, thereby improving the repair production efficiency, repair success rate or quality of lead-acid batteries;

[0074] In addition, the experiment found that when the charge and discharge voltage of the lead-acid battery is in the over-discharge range of the positive electrode, the over-discharge range of the negative electrode, or the voltage drop range of the resistance drop, the probability of battery short circuit and repair failure increases significantly when the battery temperature drops by more than 15°C.

[0075] e) In the lead-acid battery repair method provided by the present invention, when the temperature change of the lead-acid battery in steps 1, 2, 3, and 4 shows an upward trend, the heat source of the temperature rise of the lead-acid battery mainly comes from the heat generated by the lead-acid battery itself from the inside out during reverse charging and normal charging. This is beneficial to the battery to form an internally hot and externally cold temperature distribution, so that the internal reaction temperature of the battery can be higher than the temperature resistance limit of the battery shell, thereby obtaining a relatively higher electrochemical reaction temperature and a better electrochemical reaction heating response rate. On the other hand, it can make full use of the electrical energy consumed in the repair, make full use of energy or heat, save heating equipment, reduce the cooling workload, and allow the battery to carry out electrochemical reactions with a larger current (above 0.125 to 0.3C) without frequently pausing the normal reaction process for overheat removal and cooling, thereby significantly improving production efficiency.

[0076] f) In the lead-acid battery repair method provided by the present invention, when the lead-acid battery voltage is in the forward over-discharge voltage range, the reverse over-discharge voltage range, or the resistance drop voltage range in steps 2 and 4, and when the lead-acid battery body temperature drops, the charging current through the lead-acid battery is not 0. This can prevent the lead-acid battery from having an internal short circuit or reduce the probability of a short circuit.

[0077] (g) The method for repairing a lead-acid battery provided by the present invention further includes the following step between step 2 and step 3: cooling the lead-acid battery; or, cooling the lead-acid battery in step 2, and ensuring that the battery temperature at the beginning of step 3 is lower than the highest temperature reached by the battery in step 2; both of these methods are beneficial in ensuring that the temperatures in steps 1 and 2 are sufficiently high, and that the highest temperatures in steps 3 and 4 are also sufficiently high, without the former's highest temperature being lower than the latter's highest temperature. Furthermore, this method is beneficial in creating a rising trend in battery temperature during steps 1, 2, 3, and 4.

[0078] h) The method for repairing lead-acid batteries provided by this invention, in step 2, reverse charging causes a gas evolution reaction in the battery. On the one hand, the gas generated by the gas evolution reaction has a stirring effect on the electrolyte, which can make the electrolyte concentration in the battery uniform and the distribution uniform, but will not cause the original positive electrode active material to soften or fall off. On the other hand, the heat generated during the gas evolution reaction can be used to accelerate the dissolution of lead sulfate crystals on the original negative electrode and accelerate the removal or relief of sulfation problems. Furthermore, when the gas evolution reaction occurs, the battery is in an overcharged or high voltage state of reverse charging, which can also accelerate the electrochemical conversion rate of lead sulfate on the original negative electrode and facilitate the conversion or complete conversion of irreversible lead sulfate deep inside the electrode.

[0079] i) The lead-acid battery repair method provided by the present invention, in at least one step of steps 1-4, applies mechanical action to the lead-acid battery casing, thereby preventing or slowing down the deformation of the lead-acid battery casing under high temperature and internal battery pressure.

[0080] By using mechanical action to keep the lead-acid battery casing from deforming or to slow down the degree of deformation, the benefits of high temperature and gas evolution mentioned above are ensured, while the battery casing is not damaged due to deformation caused by heat or internal pressure.

[0081] j) The lead-acid battery repair method provided by this invention involves replenishing and / or removing electrolyte from the lead-acid battery before, during, and after steps 1, 2, 3, and 4. This not only ensures that the electrochemical reaction proceeds fully and completely during steps 1 to 4 without electrolyte shortage, but also helps to reduce the concentration of lead sulfate in the electrolyte, increase the amount of sulfate dissolved in the electrolyte, and remove or alleviate sulfation problems due to the reduced saturation of the lead sulfate solution. This accelerates the removal rate of battery pack inconsistencies and reduces the risk of over-discharge or reverse polarity. Short circuit problems caused by sulfate deposition; at the same time, excess electrolyte can raise the temperature for reverse charging (the reverse charging process involves a large amount of heat release and evaporation of electrolyte water), provide sufficient water or liquid volume for overcharging gas evolution, and prevent thermal runaway during reverse charging; excess electrolyte also makes it easier to find the liquid level of each cell in actual operation, making it easier to achieve or tend to be consistent in liquid level or volume among the cells; excess electrolyte helps to seal the gas channels in the separator, which helps to prevent the gas from promoting sulfidation or scouring and softening effect on the opposite electrode when a gas evolution reaction occurs at a certain electrode;

[0082] By replenishing the electrolyte, an effective cooling source can be formed at the top or sides of the individual cell. This facilitates a heat distribution of the electrolyte during the charging and discharging processes in steps 1 to 4, resulting in a cooling pattern at the top and bottom or the cooling pattern at the outside and the cooling pattern at the inside. This, combined with the charging and discharging process, promotes the circulation of the electrolyte above and below the electrode plates, achieving uniform mixing and distribution of the electrolyte within the individual cell. Simultaneously, it ensures that the electrolyte level or volume is the same in each individual cell, including both the level and volume within the battery compartment and the level and volume within the container. Replenishing the electrolyte to ensure that the electrolyte level or volume is the same in each individual cell contributes to a good consistency in the total amount and concentration of electrolyte after replenishment.

[0083] k) The lead-acid battery repair method provided by this invention, during or after step 4, further includes the following step: overcharging the lead-acid battery, wherein the overcharging includes: overcharging the lead-acid battery at least twice, discharging the battery once between the first and second overcharging, and the amount of the second overcharging is not less than the amount of the first overcharging; overcharging can eliminate the sulfation phenomenon newly formed in the electrode due to polarity reversal, so that the capacity of the repaired lead-acid battery can be better and more thoroughly restored, and it is also conducive to the lead-acid battery obtaining a better cycle life after repair; when the polarity of the lead-acid battery electrode has just returned to the symmetric charging state after polarity reversal, the porous structure of the electrode has not been fully restored, so that part of the electrode, especially the inside of the electrode, exists in the form of lead sulfate. The active materials in lead-acid batteries are difficult to react with. Therefore, the first overcharge of a lead-acid battery cannot effectively convert the lead sulfate active materials that are difficult to react into charged active materials. Even if the time or amount of the first overcharge is increased, the conversion efficiency and production efficiency of the overcharge will be lower. Performing at least one discharge and charge cycle on the battery after the first overcharge can allow the porous structure of the electrodes to be more fully restored and optimized, which is conducive to the better overcharge effect and efficiency of the second overcharge. Making the amount of the first overcharge no greater than that of the second overcharge is conducive to ensuring that the lead-acid battery achieves a good overcharge effect while ensuring good overall overcharge efficiency and making the energy consumption and time of overcharge more economical.

[0084] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description. Detailed Implementation

[0085] Preferred embodiments of the present invention are described in detail below.

[0086] Example 1

[0087] This embodiment provides a method for repairing lead-acid batteries, including the following steps:

[0088] Step 1: Discharge the lead-acid battery so that its voltage drops from a positive value to 0V;

[0089] Step 2: Perform reverse charging on the lead-acid battery, that is, use the original positive terminal of the lead-acid battery as the negative terminal and the original negative terminal as the positive terminal, and charge it in this state; so that the voltage of the lead-acid battery drops from 0V to below n×(-1.75±0.1)V.

[0090] Step 3: Perform reverse discharge on the lead-acid battery to raise its voltage from negative to 0V.

[0091] Step 4: Perform forward charging on the lead-acid battery, that is, use the original positive terminal of the lead-acid battery as the positive terminal and the original negative terminal as the negative terminal, and charge it in this state; so that the voltage of the lead-acid battery rises from 0V to n×(1.75±0.1)V or more.

[0092] During steps 1 and 2, when the voltage change of the lead-acid battery passes through the over-discharge voltage range of the forward electrode and the over-discharge voltage range of the reverse electrode, the temperature change of the lead-acid battery is maintained in an upward trend, and the temperature of the lead-acid battery is kept in an upward state without any temperature drop. The highest temperature reached by the lead-acid battery during steps 2 and 4 is higher than the upper limit of the temperature control range of the lead-acid battery during normal use or repair (e.g., 40±5℃), but does not exceed 100℃ or the boiling point of the electrolyte.

[0093] For example, the highest temperature reached by the lead-acid battery during steps 2 and 4 is higher than 40°C, 50°C, 60°C, 70°C, 80°C or 90°C.

[0094] For example, the lead-acid battery can be a lead-acid battery pack or a lead-acid single cell, wherein the lead-acid battery pack includes two or more single cells (i.e., single cells), which are connected in series and / or in parallel with each other.

[0095] The lead-acid battery includes, but is not limited to, a sealed lead-acid battery; the lead-acid battery pack includes, but is not limited to, a lead-acid battery pack in which each individual cell is connected to the other or each individual cell is connected to the other.

[0096] It should be noted that voltage values ​​> 0V are called positive voltage values, and voltage values ​​< 0V are called negative voltage values.

[0097] Compared with the prior art, the lead-acid battery repair method provided by this invention maintains the lead-acid battery temperature in a constantly rising state during step 1, without any temperature drop. This can prevent or alleviate problems such as battery short circuits, irreversible sulfation, and lead sulfate clogging of porous electrode pores caused by over-discharge. This is because, on the one hand, the discharge process in step 1 is an over-discharge process of the lead-acid battery, which means that more lead sulfate is generated and formed in the pores deep in the porous electrode. When the battery temperature remains unchanged or drops during over-discharge, it will not only increase the saturation of lead sulfate in the electrolyte and cause precipitation leading to short circuits, but also cause the lead sulfate generated by over-discharge to be generated on the basis of the original lead sulfate, making the original lead sulfate larger and more irreversible. On the other hand, the lead sulfate generated by the discharge of active material deep in the electrode plate is prone to clogging the pores of the porous electrode plate, reducing the reaction specific surface area of ​​the electrode. During over-discharge, the lead-acid battery's temperature is kept rising without any temperature drop. This helps increase the real-time dissolution of lead sulfate during over-discharge and regulates the solubility and saturation of the lead sulfate solution. This prevents or alleviates the precipitation of lead sulfate, thereby preventing or mitigating short circuits, blockage of porous electrode pores, and irreversible enlargement, thus improving the success rate of lead-acid battery repair.

[0098] Meanwhile, the reverse charging in step 2 is a process in which the over-discharge state on the lead-acid battery electrode occurs and is eliminated simultaneously. At the beginning of this process, the battery already contains a large amount of lead sulfate in a crystalline or dissolved state. Moreover, during the initial period of this process, the rate of lead sulfate formation is greater than the rate of lead sulfate elimination, which may further aggravate the over-discharge phenomenon. Therefore, similar to the reasons mentioned above, the overall temperature of the lead-acid battery in this reverse charging process is an intermediate process of rising and not falling. This is also beneficial to prevent or alleviate the battery short circuit, irreversible sulfation, and lead sulfate clogging of porous electrode pores caused by over-discharge.

[0099] Furthermore, different reaction processes differ in activation energy and reaction rate. Increasing the temperature can reduce the degree of difference in reaction rate or minimize the impact of the difference. Specifically, the reaction to remove sulfide is significantly slower than the reaction to remove softening. Coarse lead sulfate crystals have small specific surface area, low solubility, and very low reactivity, making them generally difficult to convert and requiring a long reaction time. Therefore, the reaction to remove sulfide is generally a control step to improve consistency. Increasing the battery temperature can greatly increase the solubility and reactivity of lead sulfate, thereby accelerating the removal rate of sulfide. This allows softening and sulfide to be removed simultaneously in a relatively shorter time. For example, if softening was originally removed in 1 hour and sulfide in 10 hours, after increasing the temperature, softening may be removed in 0.5 hours and sulfide in 5 hours. Thus, increasing the temperature reduces the difference or impact between removing softening and removing sulfide, and increases synchronicity.

[0100] It should be noted that in step 2 above, the heat sources for the rise in the temperature of the lead-acid battery include the heat generated by the lead-acid battery itself from the inside out during reverse charging and external heating sources (e.g., liquid heaters). It should also be noted that the heat generated by the battery pack itself from the inside out includes the heat generated by the internal chemical reaction, electrochemical reaction, and current passing through the battery's internal resistance during reverse charging.

[0101] In this process, the heat generated by the lead-acid battery itself from the inside out during discharge and reverse charging in steps 1 and 2 is the main heat source, accounting for more than 50% of the required heat. This helps to make the internal temperature of the lead-acid battery higher than the external or surface temperature of the battery, thereby maximizing the reaction temperature inside the lead-acid battery while ensuring that the battery casing (usually made of plastic) does not deform.

[0102] For example, in step 1 above, the discharge current is 10A, the voltage drops from n×(1.75±0.1)V to 0V, and the body temperature of the lead-acid battery rises from 27.6℃ to 36.8℃. Here, for n, when the lead-acid battery is a lead-acid battery pack, n is the number of individual cells connected in series in the lead-acid battery pack; when all individual cells in the lead-acid battery pack are connected in parallel, n is 1; when the lead-acid battery is a single lead-acid battery, n is 1.

[0103] For example, in step 2 above, the reverse charging current is 10A, the voltage drops from 0V to n×(-1.75±0.1)V, and the body temperature of the lead-acid battery rises from 36.9℃ to 52.93℃. Here, for n, when the lead-acid battery is a lead-acid battery pack, n is the number of individual cells connected in series in the lead-acid battery pack; when all individual cells in the lead-acid battery pack are connected in parallel, n is 1; when the lead-acid battery is a single lead-acid battery, n is 1. Studies have found that when the voltage of a lead-acid battery reaches this value, the performance (e.g., consistency) of the lead-acid battery (e.g., lead-acid battery pack) begins to improve significantly. Before reaching this value, for example, when the battery pack voltage is between n×(1.75±0.1)V and n×(-1.75±0.1)V, the consistency of the battery pack does not improve significantly and may even deteriorate. When the battery pack voltage is below this value, it helps to further improve the degree of inconsistency in the battery pack and also helps to relatively thoroughly eliminate inconsistencies in the reactivity, sulfation, softening, and passivation of active materials among individual cells. This also lays the foundation for the battery pack to achieve better consistency when it resumes forward charging. At the same time, this value is also an indicator of relatively better battery pack consistency. That is, when the battery pack voltage reaches this value, it indicates that the reverse polarity of each individual cell is relatively consistent and there are no problems such as short circuits. It should be noted that when connected in parallel, the total voltage of the lead-acid battery pack is the voltage of each individual cell. The voltage of each individual cell is equal to the voltage of the battery pack and changes synchronously. Therefore, no matter how many cells are connected in parallel, the voltage is equal to that of a single cell. When the lead-acid battery pack is composed of two or more individual cells connected in parallel, n = 1.

[0104] Considering that the over-discharge phenomenon occurring in step 2 is more severe and carries a higher risk than that in step 1, the average body temperature of the lead-acid battery in step 2 is higher than that in step 1. This serves two purposes: firstly, it further mitigates the battery short circuits, increased irreversible sulfation, and lead sulfate clogging of porous electrode pores caused by over-discharge in step 2; secondly, after the lead-acid battery voltage drops to n×(-1.75±0.1)V, reverse charging is performed at the highest possible battery body temperature, which increases the solubility of lead sulfate and accelerates the removal of irreversible lead sulfate.

[0105] Furthermore, in steps 2 and 4, when the voltage of the lead-acid battery is in the voltage regulation range of the reverse charging and forward charging, the maximum value reached by the battery body temperature or the battery body temperature is kept above room temperature or above the upper limit of the temperature control range (40±5℃) during normal use and repair of the lead-acid battery, but not exceeding 100℃ or the boiling point of the electrolyte.

[0106] For example, during steps 2 and 4, when the voltage of the lead-acid battery is in the voltage regulation range of reverse charging and forward charging, the maximum value reached by the battery body temperature or the battery body temperature is maintained above 40°C, 50°C, 60°C, 70°C, 80°C or 90°C.

[0107] Or / and, when the charge / discharge voltage of the lead-acid battery is in the over-discharge range of the forward electrode, the over-discharge range of the reverse electrode, or the voltage drop range of the resistance drop, the battery temperature drop shall not exceed 15℃;

[0108] To further repair the lead-acid battery, in steps 3 and 4, when the voltage change of the lead-acid battery passes through the over-discharge voltage range of the forward polarity and the over-discharge voltage range of the reverse polarity, the body temperature of the lead-acid battery is kept in an upward trend or state, and there is no process of body temperature decreasing.

[0109] In step 4, the voltage increases from 0V to n×(1.75±0.1), where n represents the number of individual cells connected in series in a lead-acid battery pack, 1 in parallel in a lead-acid battery pack, and 1 in a single lead-acid battery. Studies have found that from this value onwards, the performance (e.g., consistency) of lead-acid batteries (e.g., lead-acid battery packs) during the forward charging process begins to improve significantly, and the improvement is more practically significant when the state of charge of the lead-acid battery reaches or exceeds this voltage value.

[0110] Similarly, considering that the over-discharge phenomenon occurring in step 4 is more severe and riskier than that occurring in step 3, the average body temperature of the lead-acid battery in step 4 is higher than that in step 3. This serves two purposes: firstly, it further mitigates the battery short circuit, increased irreversible sulfation, and lead sulfate clogging of porous electrode pores caused by over-discharge in step 4; secondly, after the lead-acid battery voltage rises from 0V to 1.75±0.1V, charging at the highest possible battery body temperature increases the solubility of lead sulfate and accelerates the removal of irreversible lead sulfate.

[0111] To ensure that the lead-acid battery temperature remains elevated during steps 3 and 4, the following steps are included between steps 2 and 3:

[0112] Cool down the lead-acid battery.

[0113] After step 2, the lead-acid battery temperature is already very high. Cooling down is to prepare for the subsequent steps (steps 3 and 4) to raise the temperature, so that the lead-acid battery temperature can always be raised during steps 3 and 4.

[0114] Alternatively, the lead-acid battery can be cooled in step 2, so that the lead-acid battery temperature at the start of step 3 is lower than the highest temperature reached by the lead-acid battery in step 2.

[0115] For example, a liquid cooling system and / or an air cooling system are used to cool the lead-acid battery.

[0116] To prevent deformation of the lead-acid battery casing during the temperature rise process, in at least one of steps 1 to 4 above, mechanical pressure and deformation resistance are applied to the lead-acid battery casing with a rigid object. This can prevent or slow down the thermal deformation of the battery casing, and reduce concerns about the thermal deformation temperature of the battery casing, thereby further increasing the body temperature of the lead-acid battery, accelerating the reaction rate, and making fuller use of the heat generated by the reaction.

[0117] To further improve the capacity of lead-acid batteries under symmetric charging and discharging conditions, the following overcharging step is included after step 4 above:

[0118] Overcharging a lead-acid battery involves overcharging it by at least 1.5 times its rated capacity. The battery must be overcharged at least twice, with a battery discharge performed between the first and second overcharges, and the amount of the second overcharge must be no less than the amount of the first overcharge.

[0119] Overcharging refers to charging the battery to a voltage that reaches at least the gas (oxygen and / or hydrogen) evolution potential determined by the battery's electrochemical system, where the hydrogen evolution potential is n × 2.44 V, and n is the number of individual cells connected in series in the lead-acid battery. When all individual cells in the lead-acid battery are connected in parallel, then n is 1. This is because after a lead-acid battery undergoes reverse charging and then resumes symmetric charging, the reverse charging process can lead to new lead sulfate formation when the battery returns to the symmetric charging / discharging state. This phenomenon causes the battery's capacity in the symmetric charging / discharging state to decrease or fall below the battery's rated capacity. Therefore, after reverse charging and when the battery returns to the symmetric charging / discharging state, it is necessary to overcharge the battery promptly to remove lead sulfate formation and improve the battery's capacity in the symmetric charging / discharging state. This capacity should not be lower than the discharge capacity at the end of the lead-acid battery's lifespan, and may even reach or exceed the rated capacity. Test data shows that without overcharging, the capacity of a lead-acid battery is around 0.9C, while after overcharging, the capacity can reach 1.0C or higher, an increase of more than 10%. Overcharging refers to charging the battery pack until the battery pack voltage reaches at least the gas (oxygen and / or hydrogen) evolution potential determined by the battery pack's electrochemical system.

[0120] To further repair lead-acid batteries and improve their performance, during the implementation of the above repair method, before, during, and after steps 1, 2, 3, and 4, electrolyte replenishment and / or electrolyte removal operations are performed on the lead-acid batteries.

[0121] The electrolyte replenishment operation includes maintaining an excess of electrolyte in the lead-acid battery. This not only ensures that the electrochemical reactions proceed fully and completely during steps 1 to 4 without electrolyte shortage, but also helps reduce the concentration of lead sulfate in the electrolyte, increasing the amount of sulfate dissolved in the electrolyte. This reduces or eliminates sulfation problems due to the lower saturation of the lead sulfate solution, thereby accelerating the removal rate of battery pack inconsistencies and reducing short-circuit problems caused by sulfate deposition under over-discharge or reverse polarity conditions. Simultaneously, the excess electrolyte provides sufficient water or liquid for recharging during reverse polarity charging (which involves significant heat release and electrolyte evaporation) and for gas evolution during over-charging. Furthermore, replenishment creates an effective cooling source at the top of the lead-acid battery, promoting a cooler-than-hot thermal distribution of the electrolyte during the charging and discharging processes of steps 1 to 4. This, combined with the charging and discharging process, facilitates the circulation of the electrolyte above and below the electrode plates, achieving uniform mixing and distribution of the electrolyte within the single cell.

[0122] Specifically, maintaining an excess of electrolyte in a lead-acid battery includes the following steps:

[0123] To obtain the electrolyte level in a lead-acid battery, in practical applications, the operator can simply observe it visually every 1 to 3000 minutes.

[0124] Determine whether the electrolyte level in the lead-acid battery is below the threshold, i.e., whether it is below the original electrolyte level or a certain excess electrolyte level. If so, add water or an aqueous liquid (e.g., sulfuric acid solution or other aqueous solutions containing additives) to the lead-acid battery. If not, no replenishment is required.

[0125] When replenishing electrolyte, if the lead-acid battery is a battery pack, the excess amount (volume or mass) of electrolyte in each individual cell of the battery pack should be controlled within the following range: the minimum excess amount ÷ the maximum excess amount ≥ 50%. For example, if a battery pack contains 6 individual cells, and the excess amounts of electrolyte in these 6 individual cells are 20g, 24g, 28g, 32g, 36g, and 40g respectively, then the minimum excess amount 20g ÷ the maximum excess amount 40g = 50%; or, the maximum difference between the electrolyte levels of each individual cell should be less than the distance from the average electrolyte level of each individual cell to the top of the electrode or active material; or, the electrolyte levels of each individual cell should be the same.

[0126] The liquid removal process includes:

[0127] In order to restore the electrolyte level of the lead-acid battery to its original level or a certain excess electrolyte level during charging and discharging, adjust the concentration of the battery electrolyte, and keep the electrolyte level of each cell in the lead-acid battery pack as consistent as possible, the following steps may be included before step 1, during steps 1 to 4, and after step 4:

[0128] To obtain the electrolyte level in a lead-acid battery, in practical applications, the operator can simply observe it visually every 1 to 3000 minutes.

[0129] Determine whether the electrolyte level in the lead-acid battery is higher than the threshold. If so, drain the electrolyte from the lead-acid battery. For example, evaporation, overcharging and gas evolution, mechanical drainage, or liquid absorption can be used to reduce the amount of electrolyte in the lead-acid battery to the same level. If not, there is no need to reduce the amount of electrolyte.

[0130] Furthermore, the fluid replenishment and removal operations also include the following steps during or / after steps 1-4 above:

[0131] Before adding or removing electrolyte, the concentration of the electrolyte is measured and adjusted. The electrolyte concentration is adjusted to the target value by adding an aqueous solution (such as water or sulfuric acid solution) to the lead-acid battery. The target electrolyte concentration can be the original electrolyte concentration or other values. When the lead-acid battery is a battery pack, the electrolyte concentration is adjusted in the above way to make the electrolyte concentration of each cell in the battery pack consistent or tend to be consistent.

[0132] Furthermore, when performing repairs, replenishing electrolyte, or removing electrolyte, connect the electrolyte inlet at the top of the lead-acid battery to the container, while the container has another opening to the external environment of the battery; when there is excess electrolyte, the electrolyte level is higher than the top of the electrode and higher than the electrolyte inlet at the top of the battery. When observing and judging the electrolyte level, the electrolyte level in the container can be observed and judged.

[0133] Furthermore, the electrolyte level includes the electrolyte level in the battery tank and the electrolyte level in a container connected to the battery tank.

[0134] Furthermore, the replenishment and removal operations also include: performing a vacuuming operation on the lead-acid battery before, during, and after replenishment and removal to remove some gas from the battery, allowing the electrolyte to enter the battery more fully. Because used batteries may have experienced overheating runaway, dehydration, or gas evolution, a certain amount of gas occupies some of the battery's pore structure and is difficult to replace with electrolyte. Furthermore, during the repair process, when a gas evolution reaction occurs, the generated gas can easily occupy some of the battery's pore structure. To ensure the electrolyte fully contacts and reacts with the active materials, prevent post-repair fluid loss and thermal runaway, and improve the consistency of the battery pack, thereby increasing battery repair production efficiency, success rate, or quality, it is necessary to perform a vacuuming operation on the lead-acid battery before, during, and after replenishment and removal.

[0135] It should be noted that after step 4 and before removing the electrolyte, the lead-acid battery should undergo at least one more charge-discharge cycle, with a cycle depth of at least 30%. This ensures that the electrolyte participates more fully in the reaction, mixes evenly, and distributes uniformly after the electrolyte level is consistent, before electrolyte absorption, and after reversal.

[0136] Furthermore, in step 2 above, the reverse charging process of the lead-acid battery induces a gas evolution reaction in each cell. This has several advantages: firstly, the gas produced by the gas evolution reaction stirs the electrolyte, ensuring a uniform concentration and distribution of the electrolyte within the battery, without causing softening or shedding of the original positive electrode's active material; secondly, the heat generated during the gas evolution reaction can accelerate the dissolution of lead sulfate crystals on the original negative electrode, speeding up or mitigating sulfation problems; and thirdly, the battery is in an overcharged or high-voltage state during the reverse charging process, which also accelerates the electrochemical conversion rate of lead sulfate on the original negative electrode, promoting irreversible or complete conversion of lead sulfate at the electrode depth, improving battery pack consistency, and enhancing the original positive electrode's resistance to softening.

[0137] Furthermore, during or after the implementation of step 4, the following step is also included: overcharging the lead-acid battery;

[0138] Overcharging refers to charging a lead-acid battery so that the voltage is not less than the battery gas evolution reaction voltage.

[0139] The overcharge operation includes: performing at least two overcharges on the lead-acid battery, discharging the battery once between the first and second overcharges, and ensuring that the amount of the second overcharge is not less than the amount of the first overcharge.

[0140] Example 1

[0141] In this embodiment, the lead-acid battery is a used lead-acid battery pack, model 6-DZF-20, which consists of 6 individual cells connected in series, i.e., n=6, where n is the number of individual cells connected in series in the battery pack. The 6 individual cells are labeled as No. 1, No. 2, No. 3, No. 4, No. 5, and No. 6. The rated voltage and rated capacity of this lead-acid battery pack are 12V and 20Ah (2h, 25℃, the same below), respectively. The specifications and models of the 6 individual cells are the same, and the rated voltage and rated capacity of each individual cell are 2V and 20Ah. In this embodiment, the lead-acid battery pack contains electrolyte in each individual cell.

[0142] Before implementing the repair method for the lead-acid battery pack in this embodiment, it is necessary to determine the degree of inconsistency among the six individual lead-acid batteries in the battery pack. If the inconsistency exceeds a threshold, the repair method is implemented. The method for assessing the degree of inconsistency is as follows: the lead-acid battery pack is charged and discharged, and during the charging and discharging process, the voltage, current, and other electrical characteristics and differences of each individual battery are measured and compared. The specific process is as follows:

[0143] Under room temperature conditions, the lead-acid battery pack of this embodiment was charged and discharged using the following charge and discharge regime:

[0144] Step a: Discharge the lead-acid battery pack to 10.5V at a current of 10A (0.5C rate current, where C is the rated capacity of the battery pack, the same below), then charge it to 14.8V (n×2.466V) at a current of 10A, and then charge it to constant current and constant voltage at 14.8V for a total cumulative time of 3.5 hours, and let it stand for 1 hour;

[0145] Step b: Discharge the lead-acid battery pack with a constant current of 10A. Stop discharging when the voltage reaches 10.5V (n×1.75V) and let it stand for 10 minutes.

[0146] Step c: Charge the lead-acid battery pack to 14.8V using a constant current of 10A (0.5C rate);

[0147] Step d: Charge the lead-acid battery pack at a constant voltage of 14.8V, and stop when the cumulative charging time of step c (constant current charging) and step d (constant voltage charging) reaches 3.5 hours.

[0148] In step b above, when the lead-acid battery pack in this embodiment is discharged at a constant current of 10A until the battery pack voltage reaches 10.5V (t DC终 At time t (when discharge ends), the lead-acid battery pack and its individual cells are measured and examined. DC终 The voltage value at a given moment.

[0149] In step c above, when the lead-acid battery pack is charged to 14.8V (t CC终 At the moment when charging is completed, the lead-acid battery pack and its individual cells are measured and examined at t. CC终 The voltage value at a given moment.

[0150] In step d above, when the lead-acid battery pack is charged at a constant voltage of 14.8V for 10 minutes (t... CV10min (Time), measuring and examining the lead-acid battery pack and its individual cells at t CV10min The voltage value at a given moment.

[0151] In step d above, when the cumulative charging time of constant current charging in step c and constant voltage charging in step d reaches 3.5 hours (t... CV终 (Time), measuring and examining the lead-acid battery pack and its individual cells at t CV终 The voltage value at a given moment.

[0152] Table 1 shows the voltage values ​​of the battery pack and its individual cells at each of the above measurement and observation times. ΔV represents the absolute value of the difference between the maximum and minimum voltage values ​​of each individual cell at each measurement and observation time. A smaller absolute value indicates a lower degree of inconsistency in the battery pack, while a larger absolute value indicates a higher degree of inconsistency. STDEVP in Table 1 represents the overall standard deviation of the voltage values ​​of each individual cell at each measurement and observation time. A smaller STDEVP value indicates a lower degree of inconsistency in the battery pack, while a larger STDEVP value indicates a higher degree of inconsistency.

[0153] Table 1 shows the voltage values ​​(V) of the battery pack and its individual cells at each measurement and observation time.

[0154]

[0155]

[0156] Note: t DC终 ΔV = t at time t DC终 The maximum value of all single cell voltages at time t DC终 The minimum voltage of all single cells at time t = 1.908V - 1.117V = 0.791V; the calculation of ΔV at other times is similar.

[0157] t DC终 STDEVP at time t DC终 The overall standard deviation at time t = sqrt(((V1-V_average)) 2 +(V2-Vflat) 2 +......(V6-V flat) 2 ) / 6), where V_flat represents t DC终The average values ​​of V1, V2, V3, V4, V5, and V6 at time points sqrt represents the square root; STDEVP at other time points is similar.

[0158] It should be noted that when measuring the voltage values ​​shown in Table 1, the positive measuring terminal of the voltage measuring instrument is connected to the positive terminal of the lead-acid battery pack or single cell, and the negative measuring terminal of the voltage measuring instrument is connected to the negative terminal of the lead-acid battery pack or single cell; the physical connection method between the voltage measuring instrument and the battery pack or single cell is the same when voltage values ​​are mentioned below.

[0159] In addition, after step c above, the discharge capacity of the lead-acid battery pack before the repair method was measured to be 9.473 Ah (2h rate, 28℃), and the charge-discharge coulombic efficiency (charge-discharge coulombic efficiency = discharge capacity / charge capacity) was 82.2%.

[0160] Then, the lead-acid battery pack is repaired using the following methods:

[0161] Step A: Discharge the lead-acid battery pack at a constant current of 10A (0.5C rate) until the battery pack voltage drops from a positive value of 12.272V to 0V. During the voltage change, when passing through the over-discharge range (10.5±0.1V~0V), the temperature change of the lead-acid battery shows an upward trend, causing the battery temperature to rise from the initial 29.1℃ to 44.6℃, and there is no process of battery temperature decrease. In this step, the heat that causes the battery pack temperature to rise mainly comes from the heat generated by the battery pack itself from the inside out when the battery pack is discharged with a large current.

[0162] Step B: Reverse charge the lead-acid battery pack with a 10A (0.5C rate) current, causing the battery pack voltage to drop from 0V to n×(-1.75±0.1)V=-(10.5±0.6)V. During this process, the voltage change passes through the reverse over-discharge range (0~-10.5±0.1V), and the lead-acid battery temperature shows an upward trend, rising from the initial 44.6℃ to 51.2℃, without any temperature drop. Then, continue reverse charging until the battery pack voltage drops below -(10.5±0.6)V, to -12.3V, -12.6V, etc. When the battery voltage drops to -13.053V, the absolute value of the battery voltage reaches its peak (13.053V). Continue reverse charging, and the lead-acid battery voltage begins to rise (the absolute value of the voltage begins to decrease). When the voltage reaches -12.725V, the absolute value of the battery voltage reaches its trough (12.725V). When the reverse charging voltage is in the range of -13.053V to -12.725V (resistance drop voltage range), the battery temperature is maintained within the range of 60-70℃. Then, the reverse charging continues, and the battery voltage begins to drop again, becoming more negative than -12.725V. Finally, the battery voltage reaches -12.726V, and the reverse charging amount reaches 46.73Ah. In this step, the temperature of the outer surface of the battery pack is kept below 70℃ through temperature control (the temperature of the outer surface of the battery pack is used to characterize the battery pack temperature). Therefore, the highest temperature reached by the battery in this step is controlled at 70℃. In this step, the heat that causes the battery pack temperature to rise mainly comes from the heat generated by the battery pack itself from the inside out when it is reverse charged.

[0163] Note: Reverse charging refers to charging a lead-acid battery pack by treating the positive terminal as the negative terminal and vice versa. For example, -(10.5±0.6)V and -12.3V are negative voltage values, which are the results obtained when the positive terminal of the voltage measuring instrument is connected to the positive terminal of the lead-acid battery pack and the negative terminal of the voltage measuring instrument is connected to the negative terminal of the lead-acid battery pack.

[0164] Table 2 shows the voltage values ​​of each cell and the inconsistency of the battery pack in steps A and B, when the battery pack voltage drops from (10.5±0.6)V to -(10.5±0.6)V and below -(10.5±0.6)V. It can be seen that the consistency of the battery pack deteriorates in the voltage range of (10.5±0.6)V to -(10.5±0.6)V during over-discharge and reverse charging. However, after dropping to -(10.5±0.6)V (i.e., n×(-1.75±0.1)V), the degree of inconsistency of the battery pack begins to improve significantly under the reverse charging state.

[0165] Table 2 shows the voltage values ​​(V) of the battery pack and its individual cells at each measurement and observation time in steps A and B.

[0166]

[0167] Step C: Perform reverse discharge on the lead-acid battery pack at a current of 10A (0.5C rate) to raise the battery pack voltage from a negative value to 0V;

[0168] Note: Reverse discharge refers to discharging a lead-acid battery by treating the positive terminal (the positive terminal of the battery before reverse charging) as the negative terminal and the negative terminal (the negative terminal of the battery before reverse charging) as the positive terminal.

[0169] Step D: Charge the lead-acid battery pack with a 10A (0.5C rate) current in the correct orientation, causing the battery voltage to rise from 0V to n×(1.75±0.1)V=10.5±0.6V (a positive voltage value). This means the voltage change passes through the over-discharge range (0V~10.5±0.1V). Continue charging in the correct orientation until the battery voltage rises above (10.5±0.6)V, reaching 12.392V, 13.034V, etc. When the battery voltage reaches 13.216V, the absolute value of the battery voltage reaches its peak (13.216V). Continue charging in the correct orientation, and the lead-acid battery voltage will begin to decrease (electrical...). The absolute value of the voltage also begins to decrease. When the battery voltage drops to 12.361V, the absolute value of the battery voltage reaches its trough (12.361V). When the battery charging voltage is in the range of 13.216V to 12.361V (resistance drop voltage range), the battery temperature is kept within the range of 50-65℃. Then, when charging continues, the battery voltage begins to rise again and becomes higher than 12.361V. The highest temperature reached by the battery in this step is 65℃. In this step, the heat that causes the battery pack temperature to rise and be maintained above 50℃ mainly comes from the heat generated by the battery pack itself from the inside out when it is charged with reverse polarity.

[0170] Table 3 shows the voltage values ​​of each individual cell and the inconsistency of the battery pack in steps C and D, when the battery pack voltage rises from -12.6Vh to n×(1.75±0.1)V and above n×(1.75±0.1)V. It can be seen that the battery pack voltage deteriorates in the range of -n×(1.75±0.1)V to n×(1.75±0.1)V during reverse discharge and forward charging. However, after rising to (10.5±0.6)V (i.e., n×(1.75±0.1)V), the inconsistency of the battery pack begins to improve significantly under forward charging conditions.

[0171] Table 3 shows the voltage values ​​(V) of the battery pack and its individual cells at each measurement and observation time in steps C and D.

[0172]

[0173] To further analyze and compare the inconsistencies and capacity of the electrical groups, the following steps E, F, G, and H are performed.

[0174] Step E: Charge the battery pack to 14.8V with a current of 10A, then charge it at a constant voltage of 14.8V until the charging current is less than 5A, then overcharge it at a constant current of 5A for 3 hours until the battery voltage rises to 15.399V, then let it stand for 1 hour, then discharge it to 10.5V with a current of 10A, and let the battery pack stand for 10 minutes; the discharge capacity was measured to be 20.389Ah (2h rate, 36℃).

[0175] Table 4 shows the voltage values ​​(V) of the battery pack and its individual cells at each measurement and observation time in step E.

[0176]

[0177] Step F: Charge the battery pack to 14.8V at 10A, then charge it at a constant voltage of 14.8V until the current is less than 5A. Next, overcharge it at a constant current of 5A for 6 hours. During the first 3 hours of overcharging, the battery voltage rose to 15.589V, and after 6 hours, it rose to 15.659V. Then, allow it to rest for 1 hour, followed by discharging at 10A to 10.5V, and then allowing the battery pack to rest for 10 minutes. The measured discharge capacity was 22.01Ah (2-hour rate, 34.5℃).

[0178] Table 5 shows the voltage values ​​(V) of the battery pack and its individual cells at each measurement and observation time in step F.

[0179]

[0180] Step G: Charge the battery pack to 14.8V at a current of 10A, then charge it at a constant voltage of 14.8V until the cumulative charging time of constant current and constant voltage reaches 3.5h, then stop charging, let it stand for 1h, and then discharge it to 10.5V at a current of 10A, and let the battery pack stand for 10min; the discharge capacity was measured to be 20.90Ah (2h rate, 30℃), and the coulombic efficiency of charge and discharge was 92.1%.

[0181] Table 6 shows the voltage values ​​(V) of the battery pack and its individual cells at each measurement and observation time in step G.

[0182]

[0183] Comparing the battery pack consistency at each time point in Tables 1-6, it can be seen that the consistency of the battery pack in this embodiment significantly improved after steps A-G were implemented. Furthermore, regarding battery pack capacity and charge / discharge efficiency, comparing the relevant data after step G with the relevant data before step A shows that the battery pack's discharge capacity and charge / discharge efficiency increased from 9.473 Ah and 82.2% before step A to 20.9 Ah and 92.1%, respectively.

[0184] Note: 14.8V has exceeded the gas evolution potential in the electrochemical reaction system of this battery pack.

[0185] Example 2

[0186] In this embodiment, the lead-acid battery is a used valve-regulated sealed lead-acid battery with a rated capacity of 20Ah and a rated voltage of 2V. Before repair, the battery's remaining capacity was 8.7Ah (2h rate).

[0187] The lead-acid battery of this embodiment was repaired using the lead-acid battery repair method of the present invention. The specific operation is as follows:

[0188] Procedure 1) Add electrolyte until excess electrolyte is available.

[0189] To replenish electrolyte in a lead-acid battery: Place the lead-acid battery normally, remove the battery cover and valve cap that are obstructing the electrolyte inlet, and connect the electrolyte inlet at the top of each lead-acid battery to the bottom of the lead-acid battery's electrolyte reservoir. After connection, the reservoir should be located above the lead-acid battery with its top opening exposed to the atmosphere. Add water to the reservoir and the lead-acid battery until the electrolyte level is above the battery's electrolyte inlet and within the reservoir, thus creating an excess electrolyte level.

[0190] Operation 2) Perform reverse polarity charge-discharge repair on the battery in a water bath.

[0191] Step 1: Discharge the lead-acid battery to 0V with a constant current of 10A (0.5C, where C is the rated capacity of the battery);

[0192] During discharge, the battery generates heat from the inside out, causing its internal temperature to rise. This temperature rise is continuous and does not decrease. As a result, when the battery voltage discharges from a positive value of 2.014V to 0V, the battery temperature rises from room temperature (20.4℃) to 26.2℃.

[0193] Step 2: Reverse charge the lead-acid battery with a current of 10A, causing the battery voltage to drop from 0V to -2.2V, which is below n×(-1.75±0.1)V=-(1.75±0.1)V.

[0194] During reverse charging, the heat generated from the inside out of the battery causes the battery temperature to rise from 26.2℃ to 55℃ (at which point the battery voltage drops from 0V to -2.19V). During this process, there is no temperature drop during the rise of the battery temperature.

[0195] Then, continue reverse charging until the battery voltage drops to -2.228V. At this point, the absolute value of the battery voltage reaches its peak (2.228V). Continuing reverse charging will cause the lead-acid battery voltage to rise (the absolute value of the voltage will begin to decrease). When the battery voltage rises to -2.185V, stop reverse charging. The absolute value of the battery voltage at this point, 2.185V, is the lowest absolute value of the battery voltage during this reverse charging process (if reverse charging continues, the absolute value of the battery voltage will eventually drop to its trough). Thus, the battery reverse charging... When the voltage is in the range of -2.228V to -2.185V (i.e., the voltage drop range), the battery body temperature is maintained within the range of 50.4-56.5℃. In this step, the temperature of the outer surface of the battery pack's outer casing is kept below 56.5℃ through temperature control (the temperature of the outer surface of the battery pack's outer casing is used to characterize the battery pack's body temperature). The highest temperature reached by the battery body temperature in this step is 56.5℃. In this step, the heat that raises or maintains the battery body temperature mainly comes from the heat generated by the battery itself from the inside out during reverse charging.

[0196] The reverse charge in this step is 32.4 Ah.

[0197] Step 3: Perform reverse discharge on the lead-acid battery with a current of 10A, so that the voltage of the lead-acid battery rises from a negative value (-2.185V) to 0V;

[0198] Step 4: Charge the lead-acid battery with a current of 10A, raising its voltage from 0V to 2.10V, which is greater than n×(1.75±0.1)V=-(1.75V±0.1)V. Continue charging until the voltage reaches 2.143V, at which point the absolute value of the battery voltage reaches its peak (2.143V). Continuing to charge will cause the lead-acid battery voltage to begin decreasing (and its absolute value will also begin to decrease). When the battery voltage drops to 2.059V, the absolute value of the battery voltage... When the battery reaches its lowest value (2.059V), and the charging voltage is in the range of 2.143V to 2.059V (resistance drop voltage range), maintain the battery temperature within the range of 51-55.3℃. Then, continue charging with the battery in the same polarity, and the battery voltage will start to rise again and exceed 2.059V. The highest temperature reached by the battery in this step is 55.3℃. In this step, the heat that causes the battery pack temperature to rise and be maintained above 51℃ mainly comes from the heat generated by the battery pack itself from the inside out when it is charged with the reverse polarity.

[0199] Step 5: To measure the capacity recovery of the lead-acid battery and evaluate the repair effect, the lead-acid battery was continued to be charged for subsequent discharge capacity testing: The lead-acid battery was charged at 10A in the forward direction until the battery voltage reached 2.47V. Then, it was charged at a constant voltage of 2.47V until the current was less than 5A. Next, it was charged at a constant current of 5A for 6 hours until the voltage reached 2.708V, during which a gas evolution reaction occurred. After charging, the battery was discharged at 10A until 1.75V, and the battery's capacity was measured. The discharge capacity was 21.2 Ah (2h rate, 28.4℃). Then, the battery capacity at this time (after repair) was measured using the same method as before battery repair. That is, the battery was charged with a constant current of 10A from the discharge termination voltage of 1.75V to 2.47V, and then charged with a constant voltage of 2.47V until the total charging time (the sum of constant current charging time and constant voltage charging time) reached 3.5 hours. Then, it was left to stand for 1 hour, and then discharged with a constant current of 10A to 1.75V. The discharge capacity of the battery after repair was measured to be 20.24 Ah (23.6℃).

[0200] Finally, the lead-acid battery is de-liquidated by vacuum suction, which removes excess electrolyte from the acid reservoir and the battery, restoring the electrolyte level or volume to its original value.

[0201] The results of this embodiment show that the capacity of the lead-acid battery was successfully restored to its rated capacity after being repaired according to the repair method of the present invention, with a capacity improvement rate of approximately 132%.

[0202] Example 3

[0203] This embodiment uses 10 retired lead-acid batteries, all model 6-ZDF-20, numbered 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, with remaining capacities ranging from 6.0Ah to 13.7Ah. Each battery has a rated voltage of 12V and a rated capacity of 20Ah, and the six individual cells of each battery are connected in series together.

[0204] The 10 lead-acid batteries in this embodiment were repaired using the same method as the lead-acid battery repair method in Embodiment 1 of this invention.

[0205] The repair results are shown in Table 7.

[0206] Table 7 describes the repair status of lead-acid batteries No. 1-10 in Example 3.

[0207]

[0208]

[0209] Next, the repair status of lead-acid batteries No. 1-10 in this embodiment will be compared with the repair status of 10 other retired lead-acid batteries numbered 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20. The lead-acid batteries No. 11-20 in this embodiment are the same as those No. 1-10 in terms of battery model, rated capacity, rated voltage, and single-cell connection status. The remaining capacity and distribution of lead-acid batteries No. 11-20 in this embodiment are also the same or basically the same as those No. 1-10 in this embodiment.

[0210] The polarity reversal repair method is still used to repair lead-acid batteries No. 11-20 in this embodiment. However, the repair method for lead-acid batteries No. 11-20 in this embodiment (the latter method) is not completely the same as the repair method for lead-acid batteries No. 1-10 in this embodiment (the former method) (the latter method contains some features of existing repair methods). There are one or more main differences between the latter method and the former method, as described in Table 8:

[0211] Table 8 describes the repair status of lead-acid batteries No. 11-20 in Example 3.

[0212]

[0213]

[0214] Comparing Tables 7 and 8, it can be seen that for lead-acid batteries No. 1-10 in this embodiment, after using the repair method of this invention, 90% of the batteries have their discharge capacity restored to their in-service capacity, 70% of the batteries have been restored to their rated capacity, and 2 batteries have experienced short circuits or micro-short circuits. However, for lead-acid batteries No. 11-20 in this embodiment, after being repaired using a different repair method than that for No. 1-10, 50% of the batteries have their discharge capacity restored to their in-service capacity, 10% of the batteries have been restored to their rated capacity, and 4 batteries have experienced short circuits, or / and the repair process is time-consuming and energy-intensive (due to the heavy workload of heating and cooling from external heat sources). Therefore, the repair method for lead-acid batteries No. 1-10 in this embodiment is significantly superior to the repair method for lead-acid batteries No. 11-20 in terms of production efficiency, success rate, and quality.

[0215] In other embodiments of this example, eight retired 6-DZF-20 lead-acid batteries with heavy sulfation and similar (or nearly similar) remaining capacity were divided into two groups (four batteries in each group) for repair. Both groups of batteries were repaired using the lead-acid battery repair method described in Embodiment 1 of this invention. However, in the first group of batteries, the reverse charging in step 2 did not cause a gas evolution reaction, while in the second group of batteries, the reverse charging in step 2 caused a gas evolution reaction. Furthermore, the reverse charging during the gas evolution reaction... With a charge exceeding twice the rated capacity, three batteries in the second group of lead-acid batteries recovered to a capacity greater than their in-service capacity (above 18Ah) after repair, namely 19.67Ah, 21.5Ah, and 20.17Ah, with two of them recovering to their rated capacity (20Ah). In contrast, only one battery in the first group of lead-acid batteries recovered to a capacity greater than its in-service capacity (above 18Ah) after repair, namely 20.063Ah. This demonstrates that the repair success rate of the second group of batteries was significantly higher than that of the first group of lead-acid batteries.

[0216] In other embodiments of this example, experiments have confirmed that when the lead-acid battery repaired using the repair method of Embodiment 1 of the present invention is subjected to mechanical pressure and deformation resistance by a rigid object (steel plate) during the repair process of steps 1-4, compared with batteries that do not have mechanical pressure and deformation resistance applied to the lead-acid battery casing, applying mechanical pressure and deformation resistance to the lead-acid battery casing can significantly prevent or slow down the swelling and deformation of the battery casing due to heat and internal pressure.

[0217] In other embodiments of this example, the lead-acid battery (similar to the lead-acid battery in Example 1) is replenished with liquid according to the prior art, that is, water is added to the battery once or multiple times, and the amount of water added is the number of drops of battery capacity / 2-10ml. Then, the battery is repaired according to the charging and discharging method and heating and temperature control method in the lead-acid battery repair method of Example 1 of this invention. As a result, due to the characteristics of high heat and gas evolution during the repair process, the battery is prone to and actually experiences problems such as battery liquid loss and drying, and battery sulfation deterioration, resulting in battery repair failure.

[0218] The above results indicate that the lead-acid battery repair method of this embodiment has relatively high lead-acid battery repair production efficiency, repair success rate, or quality.

[0219] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for repairing a lead-acid battery, characterized in that, Includes the following steps: Step 1: Discharge the lead-acid battery to 0V; Step 2: Reverse charge the lead-acid battery to reduce its voltage from 0V to below n×(-1.75±0.1)V; Step 3: Perform reverse discharge on the lead-acid battery to raise its voltage from negative to 0V; Step 4: Perform a forward charge on the lead-acid battery to raise its voltage from 0V to n×(1.75±0.1)V or higher; During steps 2 and 4, the highest temperature reached by the lead-acid battery is higher than the upper limit of the temperature control range during normal use or repair of the lead-acid battery; or / and, in steps 1, 2, 3, and 4, when the voltage change of the lead-acid battery passes through the over-discharge voltage range of the battery's forward polarity and the over-discharge voltage range of the reverse polarity, the temperature change of the lead-acid battery is maintained to show an upward trend. The over-discharge voltage range of the positive electrode is the range of n×(1.75±0.1)V to 0V of the battery voltage, and the over-discharge voltage range of the negative electrode is the range of 0V to n×(-1.75±0.1)V of the battery voltage. Where n is the number of individual cells connected in series in the lead-acid battery pack when the lead-acid battery is a lead-acid battery pack, and n is 1 when all individual cells in the lead-acid battery pack are connected in parallel. When the lead-acid battery is a single lead-acid battery, n is 1; In step 2, the average body temperature of the lead-acid battery is greater than that in step 1. In step 4, the average body temperature of the lead-acid battery is greater than that in step 3. Before, during, and after steps 1, 2, 3, and 4, the lead-acid battery is replenished with electrolyte and / or dehydrated. After step 4, before dehydration, the lead-acid battery is subjected to at least one more charge-discharge cycle with a depth of at least 30%.

2. The method for repairing a lead-acid battery according to claim 1, characterized in that, In steps 2 and 4, when the voltage of the lead-acid battery is in the voltage drop range during reverse charging and forward charging, the maximum value reached by the battery body temperature is made or the battery body temperature is kept above room temperature or above the upper limit of the temperature control range during normal use and repair of the lead-acid battery. Or / and, when the charge / discharge voltage of the lead-acid battery is in the over-discharge range of the forward electrode, the over-discharge range of the reverse electrode, or the voltage drop range of the resistance drop, the battery temperature drop shall not exceed 15℃; Or / and, when the temperature change of a lead-acid battery is maintained as an upward trend, there is no process of battery temperature decreasing.

3. The method for repairing a lead-acid battery according to claim 1, characterized in that, The lead-acid battery is either a single lead-acid cell or a lead-acid battery pack.

4. The method for repairing a lead-acid battery according to claim 1, characterized in that, In steps 1, 2, 3, and 4, when the temperature change of the lead-acid battery shows an upward trend, the heat source of the temperature rise of the lead-acid battery mainly comes from the heat generated by the lead-acid battery itself from the inside out during reverse charging and normal charging.

5. The method for repairing a lead-acid battery according to claim 1, characterized in that, In steps 2 and 4, when the lead-acid battery voltage is in the over-discharge voltage range of the forward electrode, the over-discharge voltage range of the reverse electrode, or the voltage drop range of the resistance drop, and when the temperature of the lead-acid battery body decreases, the charging current through the lead-acid battery is not zero.

6. The method for repairing a lead-acid battery according to claim 1, characterized in that, The following steps are also included between step 2 and step 3: Cool down the lead-acid battery; Alternatively, the lead-acid battery can be cooled in step 2, so that the lead-acid battery temperature at the start of step 3 is lower than the highest temperature reached by the lead-acid battery in step 2.

7. The method for repairing a lead-acid battery according to claim 1, characterized in that, In step 2, reverse charging causes the battery to undergo a gas evolution reaction.

8. The method for repairing a lead-acid battery according to claim 1, characterized in that, In at least one of steps 1-4, mechanical action is applied to the lead-acid battery casing to prevent or slow down deformation of the lead-acid battery casing under high temperature and internal battery pressure.

9. The method for repairing a lead-acid battery according to claim 1, characterized in that, Before, during, and after steps 1, 2, 3, and 4, the lead-acid battery is replenished with electrolyte or / and de-liquidated.

10. The method for repairing a lead-acid battery according to claim 1, characterized in that, During or after the implementation of step 4, the following steps are also included: Overcharging a lead-acid battery includes: overcharging the lead-acid battery at least twice, discharging the battery once between the first and second overcharges, and ensuring that the amount of the second overcharge is not less than the amount of the first overcharge.

Images