Photovoltaic power generation component junction box

Abstract

The invention relates to a photovoltaic power generation device, in particular to a photovoltaic power generation component junction box. The photovoltaic power generation component junction box adopts the following technical scheme that the photovoltaic power generation component junction box comprises a box body, a diode chip set provided with at least one bypass diode, a packaging body used for packaging the diode chip set, and radiating fins that are used for radiating the bypass diodes, are in electrical insulation with the bypass diodes, and extend out of the box body. According to the photovoltaic power generation component junction box, the heat of the bypass diodes is led out of the junction box, so that the radiating performance of the bypass diodes is improved, and the problem of temperature rise of the bypass diodes in the prior art is solved effectively.

Description

technical field [0001] The invention relates to a photovoltaic power generation device, in particular to a junction box of a photovoltaic power generation component. Background technique [0002] Since the beginning of the 21st century, the photovoltaic new energy industry represented by solar energy has achieved rapid development; in order to improve the reliability of the current solar power generation system and overcome the unavoidable "hot shift" effect of solar cell components, the industry adopts the method of It provides bypass protection, such as providing a bypass path for every 12-24 cells connected in series; when one or several cells are blocked for some reason, the bypass diode is in forward conduction, providing bypass The road path, so that the rest of the cells that are not covered can still work normally, and at the same time avoid the damage of the covered cells due to the thermal shift effect. [0003] Arizona State University Photovoltaic Testing Labora...

AI Technical Summary

Problems solved by technology

[0007] At this time, the bypass diode 1 is in forward conduction. Under the current of 10A, the Schottky bypass diode has a power of about 5W. Since the current junction box is a closed cavity, there is no air convection heat dissipation; the heat transfer path is: Bypass diode chip--bypass diode chip plastic package--air medium in the junction box cavity--junction box plastic shell--outside; the plastic is the poor heat conduction medium of the air in the junction box cavity, and the bypass diode has serious damage Overheating; a typical temperature rise test shows that: in the current packaging form of the bypass diode R6, the junction temperature of the bypass diode is 150-200°C, the ambient temperature of the air in the junction box is about 90-110°C, and the temperature of the junction box shell is about 90 ℃; the above data show that the heat generated by the bypass diode cannot be effectively dissipated, and the gradient between the junction temperature and the ambient temperature is greater than 50 ℃; it shows that the R6 package currently used is unreasonable; although the industry adopts better heat dissipation TO263 / 220 package form, but the current structure of the junction box determines that its improvement is still limited

[0008] The more serious problem is: solar modules are installed on the roof, outdoors, deserts or plateaus with good sunshine, it is entirely possible that the bypass diodes work in the bypass state for a long time during the power generation operation, this time may be 10 minutes, it may be 10 hours, maybe even a month or more, such as a flock of birds shitting on the solar modules, blocking the cells, it is extremely unlikely to be cleaned up in time; this will cause the bypass diode to work at 150-200°C all the time Under high temperature; working at high temperature for a long time, not only the service life of the bypass diode R6 package plastic package will decrease exponentially, high heat will introduce severe thermal stress in the chip, and long-term thermal fatigue may even lead to chip fracture and permanent failure of the device; Therefore, the current thermal design of bypass diodes and junction boxes must be improved to cope with the above operating conditions

Commercial products of this principle, such as ST's SPV1001 series and the SM74611 series released by American TI in 2013; the potential problems are: high cost, and secondly, if one of the devices has reliability problems, such as wire bonding problems , will cause permanent failure of the bypass circuit

[0017] In the junction box of the solar photovoltaic power generation module disclosed in the Chinese utility model patent with the publication number CN202004017U, three independent heat dissipation blocks are arranged in the junction box, which is beneficial to the thermal isolation between the bypass diodes, but the heat dissipation is still in the junction box. In the case of ineffective heat dissipation, thermal interference between bypass diodes cannot be avoided; the photovoltaic bypass integrated module disclosed in the Chinese utility model patent with the publication number CN202651125U proposes a modular design, and its circuit electrical The design method and integrated packaging of interconnected chips do not fully consider the need for effective isolation of thermal interference between bypass diodes; another Chinese utility model patent with the publication number CN202259234U configures a unified heat sink for heat dissipation outside the junction box , still does not solve the problem of effective isolation of thermal interference between bypass diodes, and a unified heat sink will strengthen the thermal interference between bypass diodes in the solar junction box

Images