First, the charging current should be less than or equal to the charging current that the battery can receive. Otherwise, the excess current will cause the electrolyte to be consumed too quickly, resulting in the following hazards:
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Increase the water loss rate of the battery, increase the maintenance workload, and cause early failure of the battery for maintenance-free batteries; Produce acid fog, cause environmental pollution, harm the health of workers; The charging efficiency is reduced, resulting in a serious waste of energy.
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The charging process is the reverse reaction process of the discharge electrochemical reaction, if the charging electrochemical reaction process is carried out in an ideal state, this process should be reciprocal reaction, that is, the charge and the discharge of electricity should be basically equal.
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However, in the state of severe gas extraction, the electric energy consumed by the effective charging electrochemical reaction process is less than 40% of the total electricity, that is, more than 60% of the electric energy is wasted. The gas generation gathers in the porous electrode of the battery, reducing the contact area between the electrolyte and the porous electrode, that is, the charging electrochemical reaction interface is greatly reduced, so that the charging chemical reaction speed is reduced, charging is very difficult, and the charging time is prolonged.
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Severe gassing can damage the battery:
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1. The production of a large number of gases has a scouring effect on the plate active substance, making the active substance easy to soft and fall off.
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2, high polarization voltage, positive plate grid will produce serious corrosion, Pb02, this corrosion and electrochemical survival of Pb02 is completely different, is an irreversible oxide, poor conduction, and make the grid deformation, brittle, lose skeleton and conductive effect. Therefore, overcharging should be prevented as much as possible during charging. Long-term lack of charging, the unreacted active substance will produce irreversible high positive large particle PbS04 grain (that is, irreversible sulfation), so that the capacity of the battery decreases, the internal resistance increases, the charging difficulty increases, resulting in early damage to the battery.
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3, the battery should try to ensure sufficient electricity to prevent irreversible sulfation.
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The charging depth of the battery has a great influence on the cycle life, and basically changes exponentially. This is because the positive active substance is Pb02, its binding fastness is not high, it is converted into PbS04 when discharging and into PbO2 when charging, and the volume of PbSO4 is much larger than the volume of PbO2 (its volume ratio is about 2:1).
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Therefore, for the positive plate, the active substance will expand and contract repeatedly, so that the connection between its particles gradually falls off, so that the battery active substance loses its discharge characteristics and becomes \"anode mud\
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In theory, deep discharge should be avoided when the battery is used, and shallow discharge should be frequently charged, provided that there is a specially matched charger to match it. However, in actual use, because the battery charging is affected by the battery charger performance and the discrete charging habits and charging speed of the battery itself, the voltage of the charger is relatively high, and more or less overcharging exists.
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In particular, charging is mostly carried out at night, the time is generally 6-10 hours, the average is about 8 hours, if the shallow discharge, the charge will soon reach the end, then the charging efficiency becomes low, will produce overcharge. The overcharging time is relatively long, coupled with frequent charging, the battery life will be greatly affected by charging. The most ideal charging requirements are determined according to the actual situation, and the charging frequency should be determined by referring to the usual operating frequency, mileage, the description provided by the battery factory, and the performance of the supporting battery charger.
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According to the situation of the vast majority of users, the battery is best charged when the discharge depth is 50%-70%, so that the battery life can achieve the best effect. In actual use, it can be converted into cycling miles and charged once when needed.
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The impact of temperature on charging The battery runs in the high temperature season, which mainly has the problem of overcharging. When the temperature of the battery increases, the activity of each active substance increases, the positive oxygen evolution potential decreases, and the negative oxygen evolution potential also decreases (negative value decreases), therefore, the charging reaction speed is fast when charging, the charging current is large, and the charging voltage is low when charging.
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When the battery is discharged to the termination voltage, the internal resistance is large, the electrolyte concentration is very thin, especially in the plate hole and the surface is almost neutral, the internal resistance has a tendency to heat when overdischarge, the volume expands, and the discharge current is large, the heat is obviously heated (or even deformed), then the concentration of lead sulfate is particularly large, and the possibility of dendritic short circuit increases. Moreover, at this time, lead sulfate will crystallize into larger particles, that is, irreversible sulfation will be formed, which will further increase the internal resistance, and the charging recovery ability is poor or even irreparable.
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4, the battery should be used to prevent overdischarge, take \"undervoltage protection\" is a very effective measure.
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In addition, because the \"undervoltage protection\" of the electric vehicle is controlled by the controller, but some other equipment outside the controller such as voltmeter, indicator light and other power consumption appliances are directly powered by the battery, the supply of power is generally not controlled by the controller, and the electric vehicle lock (switch) begins to use electricity once it is closed. Although the current is small, overdischarge will occur if it is discharged for a long time (1-2 weeks). Therefore, the lock should not be opened for a long time and should be turned off immediately when not in use. Overcharging has been explained earlier, overcharging will increase the water loss of the battery, will accelerate the grid corrosion, the active substance softening, will increase the probability of battery deformation
When the rechargeable battery is full, there will be a little damage to forced charging, and if the frequency of strong charging is too high, it will certainly have a certain impact.
Strong charge can be fully charged in a short time, but this will cause very great damage to the battery plate, will accelerate the vulcanization of the plate, aging, and even lead to plate fall off, breakdown. So it's best not to force charging.