Although VRLA batteries have many advantages, but also with all the same reliability and battery life issues. Reported in the literature VRLA battery life of 15 years (25 ℃ float use). VRLA batteries at home and abroad, but the actual in use, have emerged ahead of the phenomenon of failure, resulting in the failure modes of VRLA batteries have increased grid corrosion and electrolyte dry, negative sulfate, premature capacity loss (PCL), thermal runaway, etc., about each of the following:
1. Dehydration
VRLA batteries from discharge of hydrogen, canon bp-2L12 charger oxygen, water vapor, mist, water loss is the way the battery and dry reason. Dry battery failure caused by this factor is the valve-regulated lead-acid battery specific. Dehydration of the reasons are the following:
① gas recombination efficiency is low;
② water seeping from the battery case;
③ grid corrosion of water consumption;
④ self-discharge loss of water;
⑤ valve failure or frequent open.
2, Premature Capacity Loss
Early loss of acer aspire as1410 battery capacity VLRA (PCL) is the battery capacity of the early cycle, with every charge and discharge cycles, the capacity decreased significantly, and in severe decline in capacity of more than 5%. Can be found in actual use the battery in a shorter time (well below the design life), battery capacity has dropped to about 80% of rated capacity, the anatomy, the internal battery grid active material, the surface diaphragm integrity, this phenomenon is premature capacity loss.
VLRA batteries are mostly used lead-calcium alloy, so the use of non-antimony alloy grid to do positive, they often cause deep charge-discharge cycle capacity of premature decay, a phenomenon originally known as non-antimony effect, it is due to positive grid and non-conductive layer of active material interface due to the formation, grid / active material interface, this layer is not conductive and low conductive layer results in a high resistance, this layer of the resistive layer during charge and discharge, fever, and to the vicinity of the cathode sony np-fp50 charger grid loss of active material expansion of activity, and thus the positive capacity decreased rapidly.
In the valve-regulated lead-acid batteries used in low-antimony or no antimony grid alloys, the early loss of capacity in the following conditions occur often easier:
① inappropriate cycling conditions, such as continuous high-rate discharge, deep discharge, charging the start of low current density;
② lack of special additives such as Sb, Sn, etc.;
③ low-rate discharge, high utilization of active material, a high degree of excess electrolyte, the plate is too thin, etc.;
④ low density of active material, the assembly of the pressure is too low and so on.
3, thermal runaway
Most of the battery system heat problems exist in the valve-regulated lead-acid batteries is more likely, this is due to oxygen recombination process within the battery to produce more heat, a small amount of exhaust gas, reducing the dell inspiron 1564 battery heat dissipation. If the working environment VRLA battery temperature is too high, or the charging voltage control equipment, the battery’s charge will be increased too fast, the battery internal temperature increases, poor battery cooling, resulting in overheating, battery internal resistance drop, charging current is further increased, the resistance is further reduced. A vicious cycle is repeated until the battery thermal runaway severely deformed shell, split up. To prevent the occurrence of thermal runaway, to adopt the following appropriate measures:
① should have temperature compensation charging equipment or limiting;
② strict quality control valve to the normal discharge of the gas within the battery;
③ To set the battery in a well-ventilated location, and control the battery temperature.
4, grid corrosion and growth
VRLA battery grid corrosion is an important reason for failure, whether in the open state, or state or float charge and discharge status, there is grid corrosion phenomenon. Especially in the over charge and discharge conditions, the cathode because oxygen evolution reaction, water is consumed, the concentration increases, leading to increased acidity near the anode, grid corrosion acceleration, canon bg-e9 battery grip positive grid corrosion at the same time subjected to deformation, so that the linear grid size increases, and even individual ribs broken, and the bus plate top edge of the plate from time to time short. Eventually leading to damage to the battery.
VRLA battery life, depending on the positive plate life, and its design life is based on positive grid alloy corrosion rate calculation. Positive grid corrosion of the more, the less the remaining battery capacity, battery life shorter.
5, negative irreversible sulfation
Under normal conditions, the formation of lead-acid batteries in the discharge of lead sulfate crystals, in charge can be more easily reduced to lead, if the improper use and maintenance of batteries, such as insufficient or too often in charge and discharge, will gradually form a negative thick hard lead sulfate, which is almost insoluble, difficult to use conventional methods of charging it into the active material, thereby reducing the battery capacity, battery life and even become a reason for termination, a phenomenon known as plate irreversible sulfation . In order to prevent irreversible sulfation negative, must charge the battery in a timely manner, not over-discharge.
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