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Analyze several repair methods for vulcanized electric vehicle batteries

by:Vglory      2021-04-02
For vulcanized batteries, you can first discharge the battery, pour out the original electrolyte and inject a relatively dilute electrolyte with a density below 1.10g/cm3, that is, add water to the battery to dilute the electrolyte to improve the solubility of lead sulfate. Use current below 20h, charge for a long time within the range of liquid temperature not exceeding 20℃~40℃, and finally adjust the electrolyte density in the battery to the standard solution concentration with a slightly higher electrolyte under the condition of full charge, general vulcanization phenomenon It can be relieved, and the capacity is restored to more than 80%, which can be considered as a successful repair. The mechanism of this method is to reduce the acid density to increase the solubility product of sulfate, and use a small current to charge for a long time to reduce the ohmic polarization to delay the early appearance of the water analysis voltage, and finally to gradually reduce the vulcanization phenomenon in the dissolution and conversion of active substances. Or eliminate. The characteristics of this method are more suitable for water-filled batteries, and the serious phenomenon of vulcanization can be solved repeatedly. It can be repaired by itself without investment in equipment. The disadvantage is that the process is too cumbersome to use sealed batteries. 2) Shallow cycle high-current charging method for vulcanized batteries, use high current within 5h of current, charge the battery to a slightly overcharged state, control the liquid temperature to not exceed 40 degrees, and then discharge 30%. Repeat this several times to reduce And eliminate the phenomenon of vulcanization. The mechanism of this method is that the overcharged gas is used to slightly wash the surface of the electrode plate with sulfide salt, so that it is desorbed and dissolved and converted into active substances. The characteristics of this method can be clearly repaired with regard to slight vulcanization. But it is not suitable for old batteries, because the active material of the positive plate is also strongly washed away while the gas is released to wash the sulfate, which makes the active material soft or even fall off. 3) Chemical repair method for vulcanized batteries, pour out the original electrolyte, add pure water, sodium sulfate, potassium sulfate, tartaric acid and other substances mixture, take normal charge and discharge several times, then pour out pure water and add a slightly higher density acid Adjust the acid solution in the battery to the standard solution concentration. If the capacity is restored to more than 80%, the repair is considered successful. According to the mechanism of this method, the added sulfate coordination dopants can form coordination compounds with many metal ions, including sulfide salts. The formed compound is unstable in acidic medium, and the non-conductive vulcanized layer will gradually dissolve and return to the solution, so that the electrode plate is vulcanized, desorbed and dissolved. The characteristics of this method, repair efficiency and efficacy are higher than the previous two repair methods, the shortcomings are too cumbersome. 4) Pulse repair Regarding vulcanized batteries, some special pulse repair instruments can be used to charge and discharge the battery several times to eliminate vulcanization. The mechanism of this method, in terms of solid physics, any insulating layer can be broken down at a sufficiently high voltage. Once the insulating layer is broken down, it will change from an insulating state to a conductive state. If an instant high voltage is applied to the sulfate layer with a large conductance difference resistance value, the large lead sulfate crystal can be broken down. If the high voltage is short enough and the current is limited, the charging current will not be caused to gas out if the sulfide layer is penetrated and the charging current is properly controlled. The amount of outgassing of the battery depends on the terminal voltage of the battery and the size of the charging current. If the pulse width is short enough and the duty cycle is large enough, the simultaneous micro-charging can be too late to form outgassing under the condition of ensuring the breakdown of the coarse lead sulfate crystals. , If it contains negative pulse depolarization, it can better ensure that the gas of the electrode plate is separated when the sulfate layer is broken down, so that the pulse elimination sulfide is realized. From the perspective of atomic physics, sulfide ions have five different energy level states, and ions in a metastable energy level state tend to migrate to a stable covalent bond energy level. In a stable covalent bond energy level state, sulfur exists in the form of a ring molecule containing 8 atoms. The ring molecule pattern of these 8 atoms is a stable combination, which is difficult to jump and be broken. The vulcanization phenomenon of the battery is This stable energy level. To break the structure of these sulfide layers, it is necessary to supply a certain amount of energy to the ring-shaped molecules, so that the electrons attached to the outer atoms are activated to the next high energy band, and the bonds between the atoms are released. Each specific energy level has a unique resonant frequency. Excessive energy outside the resonant frequency will make the transitioning atom in an unstable state. Too low energy is not enough to make the atom free from the bondage of the atomic group. In this way, the pulse repairer will operate at the frequency many times. As long as there is a resonance with the sulfide atom once during the transformation, the sulfide atom can be converted into free ions dissolved in the electrolyte, re-participate in the electrochemical reaction, and be converted back to the active material under certain conditions. This method features good effects and easy operation. But if you want to have a dedicated pulse charger, individual users don't have it, so you have to buy it. The pulse repair chargers on the market are uneven. Many pulse chargers and even special repair instruments have unreasonable designs of pulse width ratio, duty cycle, and negative pulse that cannot be used for desulfurization. The method of adding water to the electric vehicle battery is correct. Do not add water to an electric bicycle battery when the battery can only run for a few kilometers or more than ten kilometers. Don't expect to add water to increase the high capacity. Adding water is not a panacea, but the correct addition of water can extend the life of the battery. It is best to add water after the merchant’s warranty is exceeded, that is, usually about one year. Add water to the electric vehicle battery during the warranty period. After the battery is opened, the merchant does not provide the warranty. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to store and keep lithium batteries
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