This will affect the life of solar projectors!
时间:2019-01-26 浏览:2692次

Introduction: I don't know if you have encountered the newly purchased solar garden lights that have not been charged for a full period of time. In this case, we generally suspect that the products are not good, but is this really true? In addition to product factors, these are also the main factors affecting the normal operation and service life of the battery.

    (1) The rated capacity of the temperature battery refers to the value of the battery at 25C. It is generally considered that the operating temperature of the controlled sealed lead-acid battery is ideal in the range of 20~30 °C. When the battery temperature is too low, the capacity of the battery is reduced because the electrolyte does not react well with the active material of the pole under low temperature conditions. The capacity reduction will not be able to meet the expected backup time and remain within the discharge depth of the gauge, which can easily cause overdischarge of the battery. From the external parameters of the battery, the voltage temperature has a great relationship. For every 1 °C increase in temperature, the voltage of the single cell will drop by 3 mV. That is, the voltage of the acid battery has a negative temperature coefficient, which is -3 mV/ °C.

    It can be seen that at an ambient temperature of 25 ° C, an ideal charging controller can make the battery fully charged, but when the ambient temperature drops by 0 ° C, the same controller is used to charge the battery, and as a result, the battery cannot be fully charged. In the same way, when the ambient temperature rises, it will easily cause the battery to overcharge, and the temperature of the electrolyte will increase the corrosion rate of the positive plate. When the working temperature of the battery rises seriously, boiling will occur, and the electrolyte that is tumbling up and down is washed. The electrode plate causes the lead powder to fall off. After a long time, the lead powder that has fallen off is accumulating higher, and when the lead plate is hit to the lead plate, a short circuit of the plate can be generated, thereby causing the battery to be scrapped. High temperature will also bring the battery water loss and thermal runaway. Therefore, temperature is a major factor affecting the normal operation of the battery. In solar photovoltaic systems, the controller is required to have a corresponding automatic temperature compensation function. When using, the ambient temperature of the place where the battery pack is placed should be kept as high as possible and too low.

    (2) Discharge rate Generally, the capacity of the discharge rate of 20 h (also specified for 10 h) is the rated capacity of the battery. If the discharge rate is lower than the specified hour, the battery capacity higher than the rated value can be obtained; if the discharge rate is higher than the specified hour, the discharged capacity is smaller than the rated capacity of the battery, and the discharge rate also affects the battery. Terminal voltage value. When the battery is discharged, the electrochemical reaction current is preferentially distributed on the surface closest to the main solution, resulting in the formation of lead sulfate on the surface of the electrode to block the inside of the porous electrode. In the case of large current discharge, the above problems are more prominent. Therefore, the discharge current becomes larger, the capacity given by the battery is smaller, and the terminal voltage value decreases faster, that is, the discharge end voltage value decreases as the discharge current increases. On the other hand, the lower the discharge rate, the better. Some studies have shown that the long-term too small discharge rate will increase significantly due to the formation of lead sulfate molecules, causing stress to cause plate bending and active material shedding, and also reduce the battery. The service life.

    (3) Depth depth The depth of discharge has a great influence on the cycle life of the battery. If the battery is frequently deeply discharged, the cycle life will be shortened. Because deep discharge of the same rated capacity of the battery means frequent charging and discharging of large currents. When charging at high current, especially overcharge, the active material of the electrode plate is easy to fall off. In severe cases, the positive and negative plates are short-circuited; It is often in under-charged state and cannot be recharged in time. The sulfate particles produced are large, and the active material of the plate cannot be fully utilized. The actual capacity of the battery will gradually decrease and affect the normal operation of the battery. Since household solar photovoltaic systems are generally less prone to overcharging, long-term depletion is the main cause of battery failure and life shortening in domestic photovoltaic systems.

    (4) Partial discharge lead-acid batteries have a self-discharge phenomenon inside the discharge state or in a static state, which is called partial discharge. The cause of partial discharge is mainly due to the presence of impurities inside the battery. Although the electrolyte is prepared from pure concentrated sulfuric acid and pure water, it contains a small amount of impurities, and as the battery life increases, the impurities in the electrolyte slowly increase. These impurities form a myriad of micro-cells on the plates to generate partial discharges, thus unnecessarily consuming the electrical energy of the battery. In order to reduce the partial discharge of the battery, qualified sulfuric acid and pure water should be selected during installation and maintenance work to prevent harmful impurities from falling into the battery.

    Partial discharge is also related to the operating temperature of the battery. The higher the temperature, the more severe the partial discharge. In this sense, it is also necessary to avoid the battery at the excessive temperature. The battery plays an important role in the photovoltaic system. The role. However, at present, both in theory and in actual use, the problem of short battery life is a weak link in photovoltaic power generation systems. Due to the particularity of photovoltaic power generation systems, batteries as energy storage units must have good cycle discharge and depth. Discharge performance.

In the design of the battery capacity of the system configuration, it is necessary to comprehensively consider the radiation conditions of the use, the appropriate standby time, the allowable discharge depth of the selected battery, the charge and discharge efficiency, and the temperature compensation coefficient. In addition, the user should be given as much detailed guidance as possible in the user manual and technical manual of the product. If you have any questions, please leave a message.

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