Four reasons for the damage of UPS power lead-acid battery
Time of issue:2022-10-21
Ⅰ. Analysis: The main reasons for the loss of water in lead-acid batteries
The electrolytes in lead-acid batteries are as valuable as blood in the human body. Once the electrolyte disappears, it means that the battery is scrapped. The electrolyte consists of dilute sulfuric acid and water. During the charging process, it is difficult to avoid water loss, and the amount of water loss is also different depending on the charging method. In the ordinary three-stage charging mode, the water loss during charging is more than twice that of the smart pulse mode! In addition to the natural life of the battery there is a lost life: more than 90 grams of moisture loss for a single battery, the battery is scrapped. At room temperature (25°C), the water loss of ordinary chargers is about 0.25 grams, and the intelligent charging pulse is 0.12 grams. At high temperature (35°C), the universal charger loses 0.5 grams of water, and the smart charging pulse is 0.23 grams. Click here to calculate, after 250 cycles of water charging and drying for ordinary chargers, the new three-phase pulse in the water cycle will charge and dry after 600 cycles. As a result, Smart Pulse can more than double battery life.
Lead-acid batteries are the biggest problem in the charging process.
According to the research by American scientists (J.A.Mas) on the causes and laws of gas release during the charging process of lead-acid batteries, the acceptable charging current of lead-acid batteries is as follows to achieve the lowest gas release rate:
The formula of critical aeration curve is: I＝I0e－at％h＾2
During the charging process, the part of the charging current that exceeds the critical outgassing curve can only cause the battery to react with water to generate gas and heat up, but cannot increase the capacity of the battery
1. In the constant current charging stage, the charging current remains constant, the full power increases rapidly, and the voltage increases;
2. In the constant voltage charging stage, the charging voltage remains constant, the charging power continues to increase, and the charging current decreases;
3. When the battery is fully charged, the current is lower than the floating charge conversion current, and the charging voltage drops to the floating charge voltage;
4. In the floating charging stage, the charging voltage remains the floating charging voltage;
The first stage of ordinary three-phase charging is constant current charging, mainly considering that the circuit design is more convenient, not the best battery performance design.
According to the evolution process of lead-acid battery charging gas, the general gas release process in the three-phase charging process is as follows: the last cycle of constant current charging and the pre-charging of constant voltage charging, the current exceeds the evolution range of the critical gas, resulting in the gas of the battery release, resulting in a decrease in lifespan.
The current exceeding the critical gas release range will only cause the battery to generate gas and increase the temperature, but will not be converted into battery energy, thereby reducing the charging efficiency.
Solution: Pulse to solve the problem of water loss
The stage of the constant speed of the intelligent pulse is nearly an hour shorter than the constant current + constant voltage stage of the ordinary charger, and this hour of high-voltage charging is a critical moment for moisture distribution. Smart pulse is very accurate to convert light into smart pulse on the basis of turning on the voltage parameter, while the ordinary charger uses the current parameter as the turn signal. Once the battery is vulcanized, the internal resistance increases and the charging current also increases, which is difficult to achieve. Turning the lamp current can easily cause long-term charging in the high-voltage section and accelerate hydrolysis.
Ⅱ. Analysis: The reason for the lead-acid battery fixed line
Long-term battery retention, long-term overcharging and insufficient charging during the charging process, and high current discharge can easily lead to battery curing. What it looks like: one light, one fully charged, we call the battery "fake damaged". Sulfate Sulfate attaches to the plate, reducing the reaction area between the electrolyte and the plate, and the battery capacity drops rapidly. Water loss will increase the curing of the battery; vulcanization will increase the water loss of the battery, which is easy to form a vicious circle.
Solution: Smart Pulse Solution Curing
Smart Pulse The use of smart pulse spikes breaks the crystal nucleus of lead sulfate, making it difficult to form sulfate.
Intelligent pulse charger: ①Constant power, ②Intelligent pulse, ③Drip irrigation
Ordinary three levels: ①constant current, ②constant voltage, ③floating charge
Ⅲ. Analysis: Lead-acid battery is unbalanced
A battery consists of three to four. Due to the manufacturing process, the absolute balance of each cell cannot be achieved. The average current of the ordinary charger is first charged with a small-capacity single battery to form an overcharge. When the battery is discharged, the small-capacity battery is discharged first, and an overdischarge is formed. The long-term vicious cycle makes the entire battery fall behind in a single way, and the entire battery is scrapped. The three-stage charger is float-charged, with a small current of 500mA. Its function is to compensate the charging and make the battery fully charged. But it also brings two side effects: 1. Fully charged, excessive current continues, electricity is converted into heat, water is decomposed, and water distribution is accelerated; 2. Small current charging, resulting in high current bifurcation, which is easy to cause unbalanced battery packs .
Solution: Smart Pulse to Solve Unbalanced Cell Procedures
The intelligent pulsating water loss is one third of that of ordinary chargers. With less water loss, the battery voltage difference will be small; on the other hand, if the water loss is large, the battery voltage will be poor. As the water loss increases, the vulcanization will increase, and the general charger will not eliminate the vulcanization function, so the battery pack is unbalanced. Intelligent pulse charging, less water loss, small battery voltage difference, when the battery is cured, the pulse can be removed, so that the entire battery group tends to balance. Intelligent pulse constant power level high current, the functions are: 1, fast charging, saving charging time; 2, starting the battery board to eliminate the battery passivation phenomenon, restore the battery capacity, and make the entire battery capacity tend to balance. In the discharge stage, in order to eliminate the influence of the current bifurcation, the battery is fully charged and insufficiently charged, and it will automatically turn off when fully charged to reduce water splitting and maintain battery balance.
Ⅳ. Analysis: Lead-acid battery thermal runaway problem
The deformation of the battery is not a sudden, but often a process. When the battery is charged to 80% of its capacity, it enters the high voltage charging zone. At this time, oxygen is first precipitated on the positive plate, and the oxygen reaches the negative plate through the pores in the separator. The oxygen recovery reaction is carried out on the negative plate: 2Pb+O2 (oxygen)=2PbO+Q (heating); PbO+H2SO4=PbSO4+H2O+Q (heat). When the reaction reaches 90%, the oxygen production rate increases and the anode starts to produce hydrogen. The buildup of a large amount of gas causes the internal pressure of the cell to exceed the valve pressure, the safety valve opens, the gas escapes, and eventually the water is lost. 2H2O=2H2↑+O2↑. As the number of battery cycles increases, the water gradually decreases, and the battery appears as follows:
1. The oxygen "channel" becomes smooth, and the positive oxidation generated by the "channel" can easily reach a negative value;
2. The heat capacity is reduced, the battery heat capacity is the largest, the water loss is the largest, the battery heat capacity is greatly reduced, and the temperature of the heat generated by the battery rises rapidly;
3. Due to the shrinkage of the ultra-fine glass fiber separator of the dehydrated battery, the adhesion of the positive and negative plates becomes poor, the internal resistance increases, and the heat increases during the charging and discharging process. After the above process, the heat generated inside the battery can only pass the heat of the battery tank. If the calorific value is less than the calorific value, the temperature rise phenomenon. When the temperature rises, the evolution overpotential of the battery decreases, the amount of gas released increases, and a large amount of positive oxidation reacts on the surface of the negative electrode through the "channel", emitting a lot of heat, causing the temperature to rise rapidly to form a vicious circle, the so-called "thermal runaway" .