Device and method for improving charging efficiency of solar battery

Abstract

The invention provides a device and method for improving charging efficiency of a solar battery. Two groups of solar battery packs are used for charging accumulators with different nominal voltages; when the accumulator with high nominal voltage is being charged, the two groups of solar battery packs run automatically in the form of being connected in series with each other, thus obtaining high-voltage low-current output; the output power of the solar battery pack is the maximum value; when the accumulator with low voltage is being charged, the two groups of solar battery packs run automatically in the form of being connected in parallel with each other, thus obtaining low-voltage large-current output; and the output power of the solar battery pack is also the maximum value. The device and method for improving the charging efficiency of the solar battery have the advantages of overcoming the defects of the prior art, greatly improving the charging efficiency when the same solar power supply is used for charging the accumulators with different nominal voltages, and sufficiently utilizing the installation capacity of the solar battery pack.

Description

technical field [0001] The invention relates to the technical field of solar charging, in particular to a device and method for improving charging efficiency of solar cells. Background technique [0002] At present, with the depletion of fossil energy, the adoption of new energy has become an urgent issue facing mankind. One of the main uses of solar photovoltaic power is to charge batteries. In many occasions, it is required that the same solar charging power supply can charge battery packs with different nominal voltages. In the prior art, the same solar charging power supply charges battery packs with different nominal voltages. After sampling the nominal battery voltage, the nominal voltage of the battery pack is identified through the voltage identification circuit, and then the appropriate voltage is selected through the current limiting circuit. The current charges the battery pack. The solar charging power supply uses a set of solar battery packs, and its maximum ...

AI Technical Summary

Problems solved by technology

However, this power is too low for most applications. Therefore, multiple single-cell solar cells are usually connected in series / parallel to form a solar cell group, which can output the required voltage and current under full sunlight conditions. However, solar cells The maximum output current of the group will be limited by the short circuit current Isc

This important characteristic of the solar cell makes the maximum output current Io of the same solar charging power supply not greater than the short-circuit current Isc when charging battery packs with different nominal voltages, that is, when the solar charging with the highest output voltage = Vo When the power supply selects the highest nominal voltage battery pack to charge, the solar battery pack outputs the maximum power Pmax=Vo×Io, but when this solar charging power supply charges the battery pack with a lower nominal voltage, it is affected by the output current characteristics of the solar battery pack Restricted, its maximum output current Io will not be greater than the short-circuit current Isc, at this time the maximum output power of the solar cell group will also decrease accordingly

For example, there is a component of a monocrystalline silicon cell, the maximum output power Pmax (rated power) is 25W, the peak voltage (rated voltage) Ump is 17.2V, the peak current (rated current) Imp is 1.45A, and the open circuit voltage Vo is 21V. The short-circuit current Isc is 1.5A. According to the output characteristics of the solar cell, when the nominal voltage of the battery being charged is 12 volts, the charging voltage is about 14.2V, the maximum charging current is about 1.45A, and the maximum output power is about 20W; however, when the nominal voltage of the battery being charged is 6 volts, the maximum charging current is also 1.45A, at this time the maximum output power is about 10W, and the utilization rate of solar cells drops by 50%. fully utilized

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