Photovoltaic module

1. A photovoltaic module comprising:

a solar cell module including a plurality of solar cell strings formed with some of a plurality of solar cells, a plurality of bus ribbons connecting adjacent solar cell strings, and a plurality of conductive lines electrically connecting the solar cell strings and a plurality of bypass diodes; and

a junction box disposed on a rear surface of the solar cell module, the junction box comprising:

the plurality of bypass diodes;

a capacitor unit to store DC power supplied from the solar cell module;

a dc/dc converter to convert a level of stored DC power to a level-converted DC power and output the same;

a switching circuit to supply DC power supplied from the solar cell or to stop supplying DC power supplied from the solar cell;

a first current detector to detect a current supplied to the capacitor unit;

a voltage detector to detect a voltage at the capacitor unit; and

a controller to control the switching circuit to stop supplying the DC power when the detected current or the detected voltage is not within an allowable range,

wherein the plurality of conductive lines are connected with the plurality of bypass diodes and are extended to the rear surface of the solar cell module through corresponding openings penetrating the rear substrate of the solar cell module,

wherein the capacitor unit comprises a plurality of capacitors connected in parallel, in series, or in series and parallel, and the plurality of capacitors are disposed in a stacked structure within a frame,

wherein the capacitor unit is detachably mounted as a separate module in a recess within the junction box, and

wherein the switching circuit comprises:

a first switching element and a second switching element between the plurality of bypass diodes and the capacitor unit, the first switching element and the second switching element being connected in parallel; and

a resistor connected to the first switching element,

wherein the first switching element is turned on during an initial operation and the second switching element is turned on after the initial operation, and

wherein when the detected current or the detected voltage is greater than a pre-set value, the controller controls the first switching element to be turned off and the second switching element to be turned on.

2. The photovoltaic module of claim 1 , wherein the plurality of bypass diodes bypass at least one solar cell in which a reverse voltage occurs among the plurality of solar cells.

3. The photovoltaic module of claim 1 , wherein the controller outputs switching signals of the first switching element and the second switching element based on detected current from the first current detector or detected voltage from the voltage detector, and

wherein when the detected current or the detected voltage is not within the allowable range, the controller controls the first switching element and the second switching element to be turned off.

4. The photovoltaic module of claim 1 , wherein the dc/dc converter comprises at least one of a flyback converter, a boost converter, a buck converter, and a forward converter.

5. The photovoltaic module of claim 1 , wherein the junction box further comprises:

a second current detection unit to detect a current supplied to the dc/dc converter.

6. The photovoltaic module of claim 1 , further comprising:

a heat releasing member between the solar cell module and the junction box.

7. The photovoltaic module of claim 1 , wherein the switching circuit is between the plurality of bypass diodes and the capacitor unit.

8. The photovoltaic module of claim 1 , wherein one of the plurality of conductive lines connects one of the plurality of solar cell strings and one of the plurality of bypass diodes, and

wherein a first end of one of the plurality of conductive lines is connected to one of the plurality of bus ribbons, and a second end of the one of the plurality of conductive lines is connected to one of the plurality of bypass diodes.

9. The photovoltaic module of claim 1 , wherein the solar cell module further comprises:

first and second sealing members on upper and lower surfaces of the plurality of solar cells, respectively;

the rear substrate on a lower surface of the first sealing member; and

a front substrate on an upper surface of the second sealing member.

10. The photovoltaic module of claim 1 , wherein the solar cell module further comprises:

a solar cell string formed with some of the plurality of solar cells connected in a row, and a first conductive line electrically connecting the solar cell string and the junction box.

11. The photovoltaic module of claim 10 , wherein the solar cell module further comprises:

a bus ribbon connected to at least two solar cell strings; and

a second conductive line electrically connecting the bus ribbon and the junction box.

12. The photovoltaic module of claim 11 , wherein the junction box is closer to an end portion, to which the conductive line extends, between two end portions of the solar cell module.

13. A photovoltaic module comprising:

a solar cell module including a plurality of solar cell strings formed with some of a plurality of solar cells, a plurality of bus ribbons connecting adjacent solar cell strings, and a plurality of conductive lines electrically connecting the solar cell strings and a plurality of bypass diodes; and

a junction box disposed on a rear surface of the solar cell module, the junction box comprising:

the plurality of bypass diodes to bypass at least one solar cell in which a reverse voltage occurs among the plurality of solar cells,

a capacitor unit to store DC power supplied from the solar cell module, the capacitor unit detachable from the junction box;

a dc/dc converter to convert a level of the stored DC power to a level-converted DC power and output the same,

an inverter unit to convert the level-converted DC power into AC power and output the same,

a switching circuit to limit a current based on a DC current supplied from the solar cell module, and

a first current detector to detect a current supplied to the capacitor unit;

a voltage detector to detect a voltage at the capacitor unit;

a controller to control the switching circuit and to stop supplying of the DC power when the detected current or the detected voltage is not within an allowable range,

wherein the plurality of conductive lines are connected with the plurality of bypass diodes and are extended to the rear surface of the solar cell module through corresponding openings penetrating the rear substrate of the solar cell module,

wherein the capacitor unit comprises a plurality of capacitors connected in parallel, in series, or in series and parallel, and the plurality of capacitors are disposed in a stacked structure within a frame,

wherein the capacitor unit is detachably mounted as a separate module in a recess within the junction box, and

wherein the switching circuit comprises:

a first switching element and a second switching element between the plurality of bypass diodes and the capacitor unit, the first switching element and the second switching element being connected in parallel; and

a resistor connected to the first switching element,

wherein the first switching element is turned on during an initial operation and the second switching element is turned on after the initial operation, and

wherein when the detected current or the detected voltage is greater than a pre-set value, the controller controls the first switching element to be turned off and the second switching element to be turned on.

14. The photovoltaic module of claim 13 , wherein the controller outputs switching signals of the first switching element and the second switching element based on detected current from the first current detector or detected voltage from the voltage detector, and

wherein when the detected current or the detected voltage is not within the allowable range, the controller controls the first switching element and the second switching element to be turned off.

15. The photovoltaic module of claim 13 , further comprising:

a second current detection unit to detect a current supplied to the dc/dc converter,

wherein the controller controls the switching circuit based on the detection of the second current detection unit.

16. The photovoltaic module of claim 13 , wherein one of the plurality of conductive lines connects one of the plurality of solar cell strings and one of the plurality of bypass diodes, and

wherein a first end of one of the plurality of conductive lines is connected to one of the plurality of bus ribbons, and a second end of the one of the plurality of conductive lines is connected to one of the plurality of bypass diodes.