pv junction box box as an important part of the solar cell module, is between the solar cell module constitutes the solar cell square and solar cell charging control device connector, is a combination of electrical design, mechanical design and material science cross-field comprehensive design, provides the user with a combination of solar panel connection scheme. Protecting the power generation system of the whole panel, it is equivalent to a current transit station, when there is a short circuit in the cell, the junction box will automatically disconnect the short-circuited battery string.
As a kind of connector for solar cell module, the main function of pv junction box is to export the electric energy generated by solar cell module through the cable. Due to the special nature of the use of solar cells and its own expensive value, solar photovoltaic junction box must be specially designed to meet the requirements of the use of solar cell components. The connector connects the terminal block to external power devices such as inverters, controllers, etc. Connector using PC (polycarbonate) material, but PC is easy to be corroded by a variety of substances. Junction box aging is mainly reflected in the connector is easy to be corroded, plastic nut low temperature impact prone to rupture. Therefore, the service life of the junction box is reflected in the life of the connector.
A. pv junction box function
The pv junction box mainly has two functions: the basic function is to connect the photovoltaic module and the load, the current generated by the module to lead out and generate power. The additional function is to protect the module lead wires from hot spot effect. The junction box acts as a connector to bridge the solar module to the inverter and other control devices. Inside the junction box, the current generated by the solar module is drawn out through terminals and connectors and directed to the power-using device. In order to minimize the junction box on the module power loss, the conductive material used in the junction box requires low resistance, and the contact resistance of the lead wire of the busbar should be small.
II. pv junction box role
MPPT function: through the hardware and software for each panel configuration of the maximum power tracking technology and control devices, the technology can maximize the possibility of improving the panel array of different panel characteristics brought about by the power station power generation efficiency reduction, reduce the "barrel effect" on the power station efficiency, can greatly improve the power station power generation From the test results, the maximum power generation efficiency of the system can even be improved by 47.5%, which increases the investment income and greatly shortens the investment payback period.
2. Fire and other abnormal conditions intelligent shutdown function: in the event of a fire, the junction box built-in software algorithm with the hardware circuit in 10 milliseconds to determine whether an abnormality occurs, and take the initiative to cut off the connection between each block of panels, the voltage of 1000V will be reduced to about 40V human acceptable voltage to ensure the safety of firefighters.
3. The use of MOSFET thyristor integrated control technology, instead of the traditional Schottky diode. When the shadow blocking occurs, you can instantly start the MOSFET bypass current to protect the safety of the panel, while the MOSFET because of its unique low VF characteristics, so that the overall heat generation in the junction box is only one tenth of the ordinary junction box, the technology greatly extends the life of the junction box, to better protect the life of the battery.