Maintenance-free batteries have the characteristics of low price, easy portability and large capacity, and have been used in many aspects such as automobiles, motorcycles, electric bicycles, electric tricycles, emergency lights, flashlights, and UPS power supplies. However, if it is used improperly, it will cause damage to the battery and even be scrapped. In fact, as long as proper repairs are made, the capacity of most batteries can be restored to a certain extent.
1. Common problems and solutions
1. The maintenance-free battery (hereinafter referred to as the battery) basically does not produce air bubbles during charging, and can be in a sealed state, eliminating the need for maintenance work such as adding acid. However, it is impossible for the battery to not generate gas at all during the charging and discharging process. In order to release the gas, the battery cannot be completely sealed. Pry open the upper part of the battery, in order to release the gas, the battery cannot be completely sealed. Pry off the plastic cover on the upper part of the battery, you can see that each small battery has a filling hole covered with a rubber cap, and the water in the battery can evaporate through the rubber cap. Even if the battery is not in use, the water will evaporate, resulting in a decrease in battery capacity. In severe cases, the battery will dry out and cannot be charged and discharged. For this type of battery, most of the capacity of the battery can be restored by simply adding distilled or purified water to the battery and performing several charge-discharge cycles.
For example: a 12V7.2Ah battery, which is not used for a long time, discharges after charging to 14V, and the short-circuit current is only more than 300 mA. Open the top cover to check, the liquid is nearly dry, inject distilled water and perform charge-discharge cycles twice, the capacity is restored to 84%, and it can work normally.
2. When the battery is discharged, the concentration of sulfuric acid and the specific gravity of the electrolyte decrease. After complete discharge, the specific gravity at 15°C drops to 1.11. Generally, the specific gravity rises during charging, and the specific gravity after fully charged is 1.25~1.26 in summer and 1.27~1.28 in winter. Because the battery is in a sealed state, when in use, you can only judge whether it is fully charged or fully discharged according to the voltage of the battery. When the 6V and 12V batteries are fully charged, the voltages are 6.8V~7V and 13.6V~14V, respectively. When fully discharged, the voltages of the 6V and 12V batteries are 5.3V and 10.6V, respectively. If the battery is over-discharged or in a semi-discharged state for a long time, the battery will be vulcanized. The vulcanized battery cannot be eliminated by adding distilled water and conventional charging. Only when the concentration of sulfuric acid in the electrolyte is charged, the vulcanization can be eliminated.
Repair method:
(1) If the vulcanization of the battery is not serious and the capacity does not decrease much, the battery can be charged for a long time with a small current (0.05A or less).
(2) If the vulcanization of the battery is serious, it can be charged to the highest voltage (6V battery is charged to 7V, 12V battery is charged to 14V), the electrolyte in the battery is drawn out with a syringe, and then injected with distilled water to dilute the electrolyte. After charging for 1 to 2 hours, draw out the electrolyte, inject distilled water, and repeat the above operations until the specific gravity of the extracted electrolyte no longer rises significantly (usually 2 to 3 times). At this time, try to draw out the reverse electrolyte, and then inject sulfuric acid with a specific gravity of 1.25~1.28 according to the ambient temperature. If the specific gravity is small, the electrolyte can be drawn out again and injected with sulfuric acid to make the specific gravity of the electrolyte meet the standard. Note that the electrolyte injected into the battery should not be too much. After the sponge-like material in the battery is fully absorbed with the electrolyte, the excess electrolyte is drawn out, and the repair work is completed.
Example: A Sony BP60 3Ah battery, which was used as a power source for a 3/4-inch camera in the 1980s, was severely vulcanized. After repairing using the above method, the capacity was restored to 2.2Ah.
3. The battery is generally composed of several people's batteries in series (3 for 6V batteries and 6 for 12V batteries), and several batteries in series are required to have the same capacity and charge-discharge characteristics. However, the consistency of each battery is relatively poor for non-brand and poor quality batteries. After the battery is fully charged, from the perspective of the entire battery, the voltage has been charged enough, and the poor quality battery has been overcharged. When discharging, the voltage of the battery dropped to 5.3V and 10.6V, but the poor quality battery was over-discharged. Batteries with poor quality have poor performance, and in this case, they are more likely to be vulcanized, resulting in a decrease in battery capacity and early scrapping. To repair this kind of battery, the poor quality battery should be found first. The method is to drill a Φ6mm hole on the upper cover of the battery corresponding to each battery connection bridge (usually in the middle or slightly to the side of the two rubber caps), and the depth of the hole is just drilled to the lead connection bridge (do not drill through) . Then use a Φ1.5mm drill to drill a small hole with a depth of about 2mm~3mm on the connecting bridge (do not drill through). Then use a piece of copper coin with a length of about 40mm and a diameter of about 1.2mm that has been completely plated with solder to drive into the small hole of the connection bridge, and drop the melted rosin or asphalt around the copper coin (because sulfuric acid is very corrosive to the copper coin, and corrosion occurs The copper sulfate is harmful to the battery. Plating tin on the copper coin can make the contact between the copper coin and the connection bridge more closely, and protect the copper coin from being corroded by the electrolyte. The drop of rosin is to further protect the copper coin from being corroded by the electrolyte). A 12V battery can enter up to 5 copper coins, which means that the positive and negative electrodes of each small battery are drawn out, and the voltage of each small battery and the specific gravity of the electrolyte can be checked. For small batteries that have been vulcanized, the above methods can be used to repair them separately.
4. Some battery connection bridges or the external lead wires of the battery are broken (in most cases, the positive and negative lead wires are broken), and the battery cannot work. A deformed battery can only be repaired by finding the broken part. Using the above method of plated copper coins, use a multimeter to find the battery with abnormal voltage or small output current, and the breaking point is on the battery. After finding it, open a hole in the plastic cover at the break. The size of the hole should be enough to allow a soldering iron to penetrate into the break for welding, but it should not be too large. After welding, check that the connection is normal, close the opened hole with plastic or epoxy resin, and then use the above method to revive, the battery can be put into work again.
5. If there is a short-circuit fault inside the battery, the short-circuit point can be burned with low voltage and high current. If the active material falls off (indicated by the brown material in the withdrawn electrolyte), it means that the battery life has ended, and this type of battery does not need to be repaired. However, if only one or two of the batteries have expired, these two batteries can be short-circuited, and the remaining batteries can still be used as lower-voltage batteries.
Two, two points
1. Impurities (especially iron ions) are very harmful to the battery, which will cause the battery to self-discharge and shorten its life. Therefore, pay attention to purity when injecting sulfuric acid and water.
2. The hydrometer is an essential tool to repair the battery, but the commercially available hydrometer requires more electrolyte for measurement, which is difficult to use. The author used the center of the gel pen and the cap of the ballpoint pen to make a miniature simple hydrometer: put the hydrometer in pure water, and record the position of the hydrometer on the water surface, which is the scale position where the specific gravity is 1.00; Put the meter into a sulfuric acid solution with a known concentration (dilute sulfuric acid can be bought at a battery store or repair shop, ask them to accurately measure the specific gravity of sulfuric acid, such as 1.28), and note the position of the hydrometer on the liquid level; The length of the specific gravity of 1.00~1.28 is engraved on the paper, and then the scale between 1.00~1.28 is divided into 28 equal parts, and the hydrometer is completed.
Battery failure and repair
no green light
There are three reasons why the light does not turn: first, the charger parameters do not match, resulting in drift; second, the circuit problem; third, the battery factor: water loss, there is a single-cell short circuit inside the battery, and the vulcanization is more serious. Check method:
1. Check whether the charger is damaged and whether the charging parameters meet the requirements (some people use a 48V charger to charge a 36V battery pack) to see if the voltage is high (14.8V/above) or the trickle conversion current is low
2. Check whether the fuse of the charging circuit is in good contact, whether the fuse holder has any burn marks, check whether the connection of the plug connector is in good contact, and the socket on the car including the plug of the charger.
3. Check whether the battery is dry, that is, whether the battery is seriously short of liquid. The dry battery should be supplemented with pure water or 1.05g/cm3 of dilute sulfuric acid, and repaired by maintenance, charge and discharge, and at the same time, measure the single-cell voltage to see if there is a single-cell short circuit.
4. It should also be checked whether there is irreversible sulfation of the plates. If the vulcanization is serious, the internal resistance will increase, and charging will cause serious heat generation. The irreversible sulfation of the electrode plate can be determined by measuring the change of its terminal voltage by charging and discharging. When charging, the voltage of the battery rises very quickly, some cells have a particularly high voltage, and the voltage drops very quickly when discharging. When the above situation occurs, it can be judged that the battery has irreversible sulfation. If irreversible sulfation is found, it should be repaired by the equalization charging method.
battery deformation
1. Cause of failure:
The deformation of the battery is not sudden, but there is often a process. The battery enters the high-voltage charging area when it is charged to about 80% of its capacity. At this time, oxygen is first released at the positive electrode, and the oxygen passes through the pores in the separator to reach the negative electrode. Oxygen reactivation on the negative plate:
2Pb+O2=2PbO+Heat PbO+H2SO4=PbSO4+H2O+Heat
Heat is generated during the reaction. When the charging capacity reaches 90%, the oxygen generation rate increases, and the negative electrode begins to generate hydrogen. The increase in a large amount of gas causes the battery safety valve to open and the gas escapes, which eventually manifests as water loss. 2H2O=H2é+O2é , as the number of cycles of the battery increases, the moisture gradually decreases, resulting in the following situations in the battery:
(1) The oxygen "channel" becomes unblocked, and the oxygen generated by the positive electrode can easily reach the negative electrode through the "channel".
(2) The heat capacity is reduced, and the largest heat capacity in the battery is water. After the water is lost, the heat capacity of the battery is greatly reduced, and the heat generated makes the temperature of the battery rise rapidly.
(3) Due to the shrinkage of the ultra-fine glass fiber separator in the battery after water loss, the adhesion with the positive and negative plates becomes poor, the internal resistance increases, and the heat generation during charging and discharging increases. After the above process, the heat generated inside the battery can only be dissipated through the battery slot. If the heat dissipation is less than the calorific value, the temperature will rise, the gas evolution potential of the battery will decrease, and the gas evolution volume will increase. The formation of a vicious cycle leads to "thermal runaway" and deformation occurs.
2. Troubleshooting and handling
If a group of batteries (3 pieces) are deformed at the same time, check the voltage first. If the voltage is basically normal. The voltage of a single cell should also be measured to determine whether there is a short circuit. If there is no short circuit, it means that the deformation is caused by "thermal runaway" caused by overcharging. Should focus on checking the charging parameters of the charger. If the voltage is high (above 44.7V) without overcharge protection or the trickle conversion current is low, it is required to replace the charger. If only 1 or 2 of a set of batteries (3) are deformed, there is a possibility of the following failures:
(1) The battery capacity is inconsistent, causing some batteries to be overcharged and deformed during charging. The reason for the inconsistent capacity may be the existence of a short-circuit cell, or the user may discharge the battery test or self-discharge.
(2) Some batteries have irreversible sulfation of the plates, the internal resistance increases, and the charging heats up and deforms.
(3) When some batteries are connected in reverse, they cause heating and deformation during charging. Check the discharge capacity and self-discharge performance of the undeformed battery. If there is no abnormality, it is not a battery problem. The measures to solve the deformation of the battery are as follows:
*Add as much liquid as possible on the premise of ensuring no leakage, in order to prolong or avoid the occurrence of "thermal runaway".
* Avoid internal short circuits or micro-short circuits, and tend to have micro-short circuits.
* During use, the occurrence of over-discharge should be prevented, and the battery should be stored with full power.
*Strictly check the charger, there must be no serious overcharge.
* When charging at high temperature, it is necessary to ensure that the battery has good heat dissipation. Cooling measures or methods to shorten the charging time should be taken, otherwise the charging should be stopped.
Fast self-discharge
When the battery is not working, the phenomenon that the power is gradually consumed is called self-discharge. Self-discharge cannot be completely avoided. It is generally considered normal to consume 1% to 2% of its own capacity every day. If it exceeds this value, it is abnormal self-discharge.
1. Reasons for self-discharge
(1) There are impurities in the electrode material or electrolyte, so that there will be a potential difference between the impurities and the fetters or different magazines, forming a closed "local battery" to generate current and discharge the battery.
(2) The separator is broken, causing a local short circuit.
(3) There is electrolyte or water on the battery cover, so that a path is formed between the positive and negative electrodes to discharge.
(4) The active material falls off, causing the plate to short-circuit and cause discharge.
(5) When the battery is stored for a long time, the sulfuric acid in the electrolyte sinks, so that the upper part has a small density and the lower part has a large density, causing self-discharge.
2. Processing method
To reduce self-discharge, the electrolyte must be pure, and the battery cover should be kept clean during use to avoid short circuits. If the electrolyte is impure, discharge the battery with a current of 1/10 of the nominal capacity to a single cell voltage of 1.7V, then pour out the electrolyte, clean it with distilled water, and then replace it with a pure electrolyte for charging.
active substance release
1. Reasons for the release of active substances
(1) The initial charging current is too large. Because the reduction of the active material of the plate starts from the grid with the best conductivity, when the high current is charged, the lead sulfate is rapidly reduced there, so the lead sulfate far away from the grid cannot react in time, because the volume of lead sulfate is relatively large. If it is large, the adhesion with the reduced active material inside is poor, so it is easy to fall off the electrode plate.
(2) The current at the end of charging is too large. In this way, a large number of air bubbles are generated, which violently impact the surface of the electrode plate, causing a large amount of reduced and relatively soft lead dioxide to fall off.
(3) Frequent overcharging. Although the overcharge current is not large, the lead sulfate on the plate has been completely reduced to lead dioxide and lead, and the charging current is all used in the electrolyte. The impact on the surface causes the active substance to fall off.
(4) The discharge current is too large, and the chemical reaction is intense at this time, which will cause the warping of the electrode plate, thereby causing the active material to fall off.
2. Processing method
Since the active material falls off, the plate will be short-circuited, causing the battery to discharge itself. The battery must be disassembled and repaired. It is recommended to replace it.
Capacity reduction - irreversible sulfation of battery plates
1. Fault phenomenon
Plate sulfation is a common failure of batteries, and many battery failures also occur due to this failure. Plate sulfation is mainly manifested as: the voltage rises quickly during charging, gas is released prematurely, and the temperature rises rapidly; during discharge, the voltage drops rapidly and the capacity is small.
2. Troubleshooting and handling
The reasons for the irreversible sulfation of the plates are summarized as follows:
(1) The storage time is too long, the self-discharge rate is high, and it is not maintained and charged.
(2) It is not charged in time after discharge.
(3) Under-charged state for a long time.
(4) Overdischarge.
(5) Dried up or the electrolyte concentration added is too high.
When irreversible sulfation occurs in the battery, it should be repaired according to its severity.
Those with lighter salt can be restored to normal by performing general activation charging (ie, equalizing charging) on them. The specific method is as follows:
Constant voltage current-limiting charging: The first stage is 0.18C2A charging to 2.7V/single cell charging for 12-24 hours.
The first stage of constant current: 0.18C2A is charged to 2.4V/single cell, and the second stage: 0.05C2A is charged for 5-12 hours. Those with heavier salinity need to be charged and discharged with "hydrotherapy" to return to normal. The specific method is: first add pure water or dilute sulfuric acid with a density of 1.05g/cm3 to the battery to a rich liquid state, then charge the battery with a current of 0.05-0.018C2A for about 20 hours, drain the flowing liquid, and then do a capacity test. Repeat the above operations until the battery capacity is restored.
The distance is not far - the battery pack appears "unbalanced"
1. Fault phenomenon
The balance of series-connected battery packs is a common problem, and there will always be "backward" batteries in the process of use. The reasons are various, there are production reasons, there are also reasons for raw materials and reasons for use.
2. Troubleshooting and handling
First, the battery is charged for general maintenance, and then discharged with a 2h rate current. During the discharge process, the voltage of the battery is continuously measured, and the "backward" batteries with insufficient discharge capacity are selected for treatment. First add 1.05g/cm3 of dilute sulfuric acid until you just see the flowing electrolyte, and then continue to charge for 12~15h. Be careful not to exceed the temperature of the battery over 50 degrees when charging. After charging, let stand for 0.5~4h, redo 2h rate discharge. During the discharge process, measure the value of the single-cell voltage. If the discharge time does not meet the standard or the single-cell voltage reaches 1.6V, the discharge time is greatly different from the normal single-cell battery (the difference is more than 5 minutes for three months after leaving the factory, and six months). If the difference is more than 8 minutes, the difference is more than 10 minutes in nine months, and the difference is more than 15 minutes in thirteen months), the above charging and discharging procedures need to be repeated until the requirements are met.
If the battery capacity does not increase significantly after repeated charging and discharging cycles or is still at a low voltage of about 0V, this kind of battery generally has a short circuit, or the active material is seriously detached and softened, and the serious irreversible sulfation cannot be repaired. It should be scrapped. Those who meet the requirements can continue to use the battery. Under the charging condition of constant voltage of 15V per battery, drain the electrolyte, wipe the surface of the battery, install the cap valve, and stick the panel with PVC (or chloroform) adhesive. good.
Single cell short circuit
1. Fault phenomenon
The phenomenon is that the starting ability is suddenly lost; when starting, the short-circuit cell has electrolyte sprayed out. The reason is: after a single cell is short-circuited, the resistance of the battery increases, the voltage decreases, and a strong current cannot be supplied.
2. Cause of failure
(1) The active substance falls off.
(2) The electrolyte used has impurities.
3. Inspection and processing
The inspection method can be used to ignite the positive and negative electrodes of each grid of a thin wire. The grid with no spark or weak spark is short grid and needs to be sent for repair.
Water replenishment of battery
(1) Preparations. Use pure water and analytically pure sulfuric acid to prepare sulfuric acid solution electrolyte, the ratio is: 500ml pure water, add 0.5ml pure sulfuric acid. Prepare a standard rubber vent valve as a spare. Tools: screwdriver, straw (can be replaced with disposable needle), transparent polyethylene tube, the diameter should be suitable for the suction mouth of the straw (needle), ABS glue.
(2) Pry off the cover above the battery along the vent hole. Some battery covers are ABS glued, and some batteries are snap-connected. Be careful not to damage the cover when prying open the cover. This is the rubber cap where the 6 exhaust valves can be seen.
(3) Open the rubber cap to expose the vent hole, through which the inside of the battery can be seen. The exhaust valve of some batteries can be unscrewed, and there are some fillers around the rubber caps of some batteries. Pay attention to the fillers.
(4) Use the dropper to inhale the configured electrolyte and inject the electrolyte through the vent hole. The electrolyte should just cover the plate by 1mm.
(5) Cover the vent hole with a cover-up cover to prevent dust from falling into the vent hole, and let it stand for 12-24 hours so that the electrolyte can fully penetrate. Observe the electrolyte inside the vent again, there should be a flowing electrolyte (free acid), otherwise the electrolyte should be replenished.
(6) Under the condition that the exhaust hole is not covered, carry out 16.2V constant voltage current limiting charging. When charging, it is best to put the battery in an acid-resistant container to prevent the spilled electrolyte from polluting the environment. When the charging current of the battery drops to 400~300 mA, or the voltage reaches 16.2V for more than three hours, the battery is considered to be fully charged for the first time.
(7) After the initial charging, check whether there is any electrolyte on the surface of the battery plate. If there is no electrolyte, the electrolyte should be replenished, and then the constant voltage current-limiting charging should be performed again; if there is electrolyte on the 6 grids, use a straw Aspirate excess electrolyte.
(8) Use 14.8V constant voltage current limiting charging until the charging current drops to 300mA.
(9) After closing the exhaust valve, pay attention to restoring the filling. Cover the battery cover, if it is glued, it should be glued. Press a heavy object on the battery cover, wait for the glue to completely solidify, and perform 4.8V constant voltage current limiting charging again until the charging current drops to 300mA.
(10) Test the battery capacity again to determine whether the battery capacity is restored.
The reasons for the unsatisfactory effect of the battery after repair (the capacity increase is not large, or the battery does not reach more than 70% of the nominal capacity) are as follows:
1. The positive plate of the battery is softened. The obvious manifestation is: in the above step (7), it will be found that there are black impurities in the excess electrolyte that is sucked out. If there are many black impurities, the positive plate is softened and discharged, such as Batteries basically cannot be repaired, they can only be scrapped.
2. The battery is vulcanized, and the battery can be repaired by electronic pulse for 24 hours after being recharged, and then tested again.
3. 30min after charging, test the battery voltage, it is still lower than 12V, it may be the internal circuit breaker of the battery, the battery should be scrapped.
How to solve the vulcanization problem of electric vehicle batteries
Regular maintenance: Regularly go to a professional maintenance point to repair the battery every three months, and replenish water in time. These methods are simple and easy to implement, and the economic cost is very low, but it is difficult to strictly follow them. Therefore, most of them use special equipment for sulfur removal and maintenance. The methods are as follows:
1. Use desktop rapid desulfurization equipment
The working principle of the desktop rapid desulfurization equipment is high-voltage and high-current pulse charging to eliminate sulfuration through negative resistance breakdown. This method is fast and effective, and can temporarily eliminate vulcanization. However, high voltage and high current can remove sulfur and active substances, which brings serious water loss and softening of positive plates in eliminating vulcanization. It will cause fatal damage to the battery, and the battery that has been desulphurized twice by this type of equipment will basically be scrapped. At present, professional battery maintenance shopkeepers in the market have understood the harm of this method. Therefore, pulse discharge desulfurization equipment has appeared. In fact, the fundamental principle has not changed, but it has changed from constant high voltage and constant current to instantaneous The peak high voltage will still damage the active material of the plate.
2. Choose a sulphur-removing charger
At present, there are three working principles of desulphurization chargers. One is similar to the working principle of desktop rapid desulphurization equipment. It uses high voltage and high current pulse charging to remove sulfur through negative resistance breakdown. Longevity constitutes a fatal injury, which has been denied by the market. The second is to use the charging and discharging pulse of the fast pulse leading edge, and use the instantaneous peak value to interfere with the vulcanization of the battery during the charging process. The other is to periodically use a 10% to 20% overcharge method to restore the lead sulfate crystals of the battery.
3. Use online lead-acid battery life extension device
The on-line lead-acid battery generator is connected in parallel with the battery to prevent and eliminate vulcanization 24 hours a day. This method is relatively slow to repair, and the repair time is relatively long, often more than 120 hours, but whether it is charging or discharging, it can prevent and eliminate vulcanization, and the repair effect is very good. Because of the use of low voltage and low current, the generator will not have a strong impact on the battery plate, resulting in water loss and softening. This is a maintenance method that users can persevere with one investment, especially for new batteries with better quality. Extends the battery life by 2~5 times, and once invested, it can always accompany the electric automatic vehicle. The next time the battery is replaced, the life extension device can continue to be used, which can save a lot of economic costs for users.
Taking this approach makes a lot of sense. The first is to bring real economic benefits to users and reduce the troubles of users. The second is to improve the reputation of the depot and provide conditions for expanding production. Third, it solves the problem of battery quality assurance for electric vehicle dealers, reduces complaints, improves credibility, and increases profits. Fourth, it can greatly reduce the cost of claim settlement for battery manufacturers. Fifth, improve the image of electric bicycles and expand the development of the overall market of electric bicycles. Sixth, improving the utilization rate of the battery is conducive to environmental protection.
The advantages mentioned above are actually just one sentence, that is, the benefits of extending the battery life. In fact, the actual use is not as good as the above paragraph touted. Some people I know have used it and said that it has no effect, but now they don't use it, and they say that it can prolong the lifespan by 2 to 5 times! General batteries, pay a little attention to the usage and precautions, generally can be used for one and a half years, and the better ones can be used for two years or more. This is used on electric vehicles, not as a backup power source for lighting. I have heard that electric vehicles use three-year batteries, but never 10 years. Unless you charge every day, you only need to run a kilometer or two every day.
