JPH11274544A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module which can suppress the damage minimum due to the lightening surge. SOLUTION: This solar cell module comprises serially connected solar cells 3 and bypass diodes 10 connected in parallel to the series connections of the solar cells 3 with arresters 11 connected in parallel to the bypass diodes to absorb the lightening surge. Together therewith, or separately temp. fuses which will fuse due to the heat of the bypass diodes 10 may be connected in series to the bypass diodes 10 or current fuses may be connected in series to the bypass diodes 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell module for supplying electric power using solar energy.

[0002]

2. Description of the Related Art In 1994, a system in which the government subsidizes a part of the cost of installing a residential photovoltaic power generation system in a general home was started. The number of homes to install is increasing.

[0003] A residential photovoltaic power generation system mainly comprises a solar cell module, and generally has a configuration as shown in FIG. In FIG. 7, reference numeral 20 denotes a solar cell array including a plurality of solar cell modules 21, 22 denotes a stand thereof, 23 denotes a DC connection box, 24 denotes an inverter, 25 denotes a distribution board, and 26 denotes a watt hour meter.

In a standard photovoltaic solar power generation system installed in a general home, 24 solar cell modules each having a capacity of about 130 W are installed, so that a power generation of about 3 kW can be obtained on a sunny day. It has become. Specifically, each solar cell module has an output of about 26 V and 5 A, and eight of these are connected in series, and the module rows are further connected in parallel with three systems. Approximately 3 kW of 15 A at approximately 200 V.

[0005] The solar cell module 21 is usually
It has the appearance as shown in FIG. 8, and is obtained by laminating a number of layers of solar cells 27 arranged in a plane with surface glass or the like and packaging them in a plate shape. And on the back,
A terminal box 29 having a pair of output cords 28a and 28b is attached.

As shown in FIG. 9, the circuit configuration of this solar cell module 21 is such that a large number of solar cells 27 are connected in series with each other, and a bypass diode 30 is provided in each of a plurality of columns of the solar cells 27. They are connected in parallel. Here, the bypass diode 30 is configured such that when part or all of the solar cell 27 does not generate an output due to a failure or interruption of incident light,
An electric path for avoiding these solar cells 27 is formed. Normal solar cells 27 or normal solar cell modules 21 are connected to each other via this bypass diode 30. The output of the normal part can be taken out to the outside.

[0007]

Since the solar cell module 21 is installed outdoors, it is susceptible to lightning surge. Then, when the lightning surge is received, the solar cell 27 of the solar cell module 21 is relatively less damaged, but the bypass diode 30 is in a breakdown state due to internal destruction and may conduct in the reverse direction. In that case, both ends of the column of the corresponding solar cell 27 are shortened through the bypass diode 30.

When the bypass diode 30 short-circuits the solar cell 27 in this way, the solar cell module 21 cannot be used, and in some cases, a dangerous situation may be caused. That is, when the solar cell module 21 is exposed to sunlight while the bypass diode 30 is short-circuiting the solar cell 27, a large voltage and a large current are instantaneously generated in the row of the solar cell 27. Therefore, the bypass diode 30 through which a large current flows generates heat and may be ignited by overheating.

In the conventional solar cell module, various measures have been taken to enhance the safety. However, the damage from the lightning surge and the danger of the bypass diode short-circuited by the lightning surge have been fully recognized. At present, safety measures taking these factors into account are neglected.

[0010] The present invention has been made in view of such a situation, and minimizes the damage of a bypass diode due to a lightning surge, and prevents the bypass diode from overheating or igniting even if it is damaged. An object of the present invention is to provide a solar cell module having a configuration that can be prevented beforehand and having improved safety.

[0011]

In the solar cell module according to the present invention, a large number of solar cells are connected in series with each other, and a bypass diode is connected in parallel to each or a plurality of columns of these solar cells. In order to eliminate the inconvenience described above, the following configuration is adopted.

That is, in the first invention, the lightning arrester is connected in parallel to the bypass diode. Further, in the second invention, a configuration is adopted in which a thermal fuse receiving heat generated by the bypass diode is connected in series to the bypass diode. Further, in the third invention, the current fuse is connected in series to the bypass diode. In the second and third inventions, an indicator is provided to indicate the fusing of the thermal fuse or the current fuse.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show an embodiment including the first, second and third inventions. FIG. 1 is an exploded perspective view of a solar cell module according to the embodiment, and FIG. FIG. 3 and FIG. 3 are circuit diagrams of a bypass unit which is a part of the circuit.

As shown in FIG. 1, the solar cell module according to this embodiment basically includes a surface glass 1 and an E glass.
A VA resin layer 2, a main body layer 4 composed of a large number of solar cells 3, an EVA resin layer 5 on the back side, and a back film 6 are sequentially laminated, and these are integrated by lamination, and an output code is formed on the back side. A terminal box 8 having 7a and 7b is attached, and this basic structure is not particularly different from a conventional solar cell module. Each of the EVA resin layers 2 and 5 is an EVA resin film having a thickness of about 0.4 mm, and the back film 6 is a Tedlar /
It is a film having a thickness of 110 μm having a three-layer structure of Al / Tedlar.

Further, holes for extracting power are formed in the EVA resin layer 5 and the back film 6 on the back side in advance, and after lamination, the output cords 7a, 7b are passed through the holes and the main body layer 4 is formed. Is connected to the internal circuit of. The terminal box 8 is provided with each output code 7a, 7
This is provided to protect the connection portion between b and the internal circuit in terms of strength and water resistance.

The main body layer 4 is configured by arranging a large number of solar cells 3 in a plane. In this embodiment, the main body layer 4 includes a bypass unit 9 as an additional circuit. The bypass unit 9 is incorporated and packaged within the thickness of the solar cell module, like the solar cell 3. As shown in FIG. 2, the circuit configuration of the solar cells 3 and the bypass unit 9 in the main body layer 4 is such that a large number of solar cells 3 are connected in series and And bypass units 9 are connected in parallel.

The bypass unit 9 is a circuit composed mainly of a bypass diode 10. In the bypass diode 10, a part or all of a large number of solar cells 3 connected in series due to a failure or interruption of incident light is connected. When an output is not normally generated, an electric path for avoiding these solar cells 3 is formed. The circuit configuration of the bypass unit 9 is shown in FIG. The bypass unit 9 includes the lightning arrester 1 in addition to the bypass diode 10.
1, a temperature fuse 12, a current fuse 13, a light emitting diode 14 as an indicator, and a protection resistor 15 thereof.

The lightning arrester 11 is composed of, for example, a varistor and serves to absorb a lightning surge applied to the bypass diode 10 side, and is connected in parallel to the bypass diode 10. The thermal fuse 12 cuts off an electric path to the bypass diode 10 by fusing the fuse by receiving heat generated by the bypass diode 10. A parallel circuit including the bypass diode 10 and the lightning arrester 11 is located near the bypass diode 10. Are connected in series.

The current fuse 13 cuts off an electric path to the bypass diode 10 by being blown by a reverse current to the bypass diode 10, and is connected in series with a parallel circuit including the bypass diode 10 and the lightning arrester 11. It is connected to the. The light emitting diode 14 is used to indicate the fusing of the thermal fuse 12 or the current fuse 13 by lighting. It is connected to the.

Next, the operation of the above configuration will be described by dividing into (a) surge absorption stage, (b) short circuit, unheated stage, (c) short circuit, and overheat stage.

(A) Surge absorption stage.

When a photovoltaic module receives a lightning surge, the lightning surge is applied to both the row of the photovoltaic cells 3 and the bypass unit 10, but the photovoltaic cells 3 are hardly damaged in many cases. In the bypass unit 10,
If the magnitude of the lightning surge is within the allowable amount of the lightning arrester 11, the lightning surge will be absorbed by the lightning arrester 11, and will hardly be applied to the bypass diode 10. Therefore, the bypass diode 10 is protected from lightning surge, and does not lead to short-circuiting of the corresponding row of the solar cells 3.

As described above, the lightning arrester 11 only needs to be connected in parallel with the bypass diode 10 since it only needs to absorb the lightning surge that would be applied to the bypass diode 10. Unlike the embodiment, it may be attached as shown in FIG. That is, in the embodiment of FIG. 4, a bypass unit 16 (circuit obtained by removing the lightning arrester 11 from the circuit of FIG. 3) that does not include the lightning arrester 11 is configured and connected in parallel to the row of the solar cells 3. The lightning arrester 11 is connected in parallel with the bypass unit 16. In this circuit configuration, a lightning surge that would be applied to the bypass unit 16 that does not include the lightning arrester 11 will be absorbed by the lightning arrester 11, and the bypass unit 1
6 does not add to the bypass diode 10.

(B) Short circuit, unheated stage.

If the lightning surge applied to the bypass unit 10 is larger than the allowable amount of the lightning arrester 11, the lightning surge is also applied to the bypass diode 10, and as a result of the lightning surge, the bypass diode 10 is internally destroyed. Conduction also occurs in the opposite direction, and the corresponding row of solar cells 3 is short-circuited. Then, after the row of the solar cells 3 is short-circuited by the bypass diode 10, when the solar cells 3 receive the sunlight and perform the power generation operation,
The current generated by the power generation flows through the bypass diode 10, and the bypass diode 10 generates heat.

At this time, if the power generated by the photovoltaic cells 3 is large, the short-circuited bypass diode 10 may overheat and ignite, but if the generated power is small or nil, the bypass diode 10 Do not overheat. However, since the short-circuited bypass diode 10 has a short-circuited part in the middle of the series circuit of the entire solar battery cell 3, the output of the solar battery module cannot be taken out.

In this case, a reverse voltage may be applied to the output cords 7a and 7b of the solar cell module, and a reverse current may flow through the bypass unit 9. That is, since the bypass diode 10 in the bypass unit 9 is in a short-circuit state, the current in the reverse direction is
3. The current flows through a series circuit composed of a bypass diode 10 and a thermal fuse 12, and the current fuse 1
3 is blown, and the electric path to the bypass diode 10 is cut off. Thus, the bypass diode 10 in the short-circuit state can be forcibly separated from the series circuit of the solar cells 3 by an operation from the outside, and the state where the corresponding row of the solar cells 3 is short-circuited is eliminated. You.

When the electric path to the bypass diode 10 is cut off as described above, the power generated by the solar cell 3 is supplied to the light emitting diode 14 in parallel with the bypass diode 10 and the current fuse 13.
4 lights up. When the light emitting diode 14 is turned on, the fact that the current fuse 13 has blown can be visually recognized from the outside. It is to be noted that the series circuit of the solar cells 3 does not have the bypass diode 10 only by separating the bypass diode 10 in the short-circuit state. Therefore, a separate bypass diode is prepared, and the solar cell 3 is externally mounted. 3
May be connected to the series circuit. If the bypass diode is externally connected, the solar cell module will have the same circuit as the original, so that the output can be taken out.

(C) Short circuit, overheating stage.

When the solar cell 3 receives strong sunlight and generates large power after the row of the solar cell 3 is short-circuited by the damaged bypass diode 10, a large current flows through the bypass diode 10. Thus, the bypass diode 10 is overheated. If the overheating continues, the bypass diode 10 may be ignited. However, in the configuration of this embodiment, there is a thermal fuse 12 near the bypass diode 10, and the thermal fuse 12 receives the heat of the bypass diode 10 and blows. Before the bypass diode 10 is ignited,
As a result, no more current flows through the bypass diode 10 as a result. As a result, ignition of the short-circuited bypass diode 10 is prevented.

When the thermal fuse 12 is blown and the electric circuit to the bypass diode 10 is cut off, the power generated by the solar cell 3 is supplied to the light emitting diode 14, and the light emitting diode 14 is turned on. By the lighting, it is displayed that the melting of the thermal fuse 12 can be visually recognized from the outside. In this case, as in the case where the current fuse 13 is blown, the series circuit of the photovoltaic cells 3 does not have the bypass diode 10 just by interrupting the electric circuit to the bypass diode 10. If a bypass diode is prepared and externally connected, the output can be taken out from the solar cell module as before.

FIGS. 1 to 3 show solar cell modules having both the first to third aspects of the present invention. As shown in FIGS. 5 and 6, each of the aspects of the present invention is separately implemented. It is also possible.

FIG. 5 is a circuit diagram of a solar cell module according to an embodiment corresponding to the first invention. In this solar cell module, a large number of solar cells 3 are connected in series with each other, and these solar cells 3 The bypass diodes 10 are connected in parallel to a plurality of columns, and a lightning arrester 11 such as a varistor is connected to each bypass diode 10 in parallel. Also in this solar cell module, the lightning surge that would be applied to the bypass diode 10 is absorbed by the lightning arrester 11, so that the bypass diode 10 is protected from the lightning surge.

FIG. 6 is a circuit diagram of a solar cell module according to an embodiment corresponding to the second or third invention. In this solar cell module, a large number of solar cells 3 are connected in series with each other, and a bypass diode 10 is also connected in parallel to a row composed of a plurality of the solar cells 3. A thermal fuse 12 that receives and blows or a current fuse 13 that blows by a reverse current is connected in series to the bypass diode 10. Further, a light emitting diode 14 with a protection resistor 15 is connected in parallel to a series circuit including a bypass diode 10 and a fuse (thermal fuse 12 or current fuse 13).

In the case where the thermal fuse 12 is provided, after the bypass diode 10 is short-circuited by a lightning surge, heat is generated by the generated current of the photovoltaic cell 3, and when overheated, the thermal fuse 12 is blown. Therefore, the electric circuit to the bypass diode 10 in the short-circuit state is cut off, and the ignition of the bypass diode 10 is prevented beforehand. Then, the fact that the thermal fuse 12 has blown is indicated by the lighting of the light emitting diode 14.

In the case where the current fuse 13 is provided, after the bypass diode 10 is short-circuited by receiving a lightning surge, a current in the reverse direction is supplied to a series circuit of the bypass diode 10 and the current fuse 13. As a result, the current fuse 13 is blown and the bypass diode 1
The circuit to 0 is interrupted. As a result, the bypass diode 10 that may cause overheating or fire is separated from the series circuit of the solar cells 3. The blowing of the current fuse 13 in this case is also indicated by the lighting of the light emitting diode 14.

In each of the above embodiments, the bypass diode 10 is connected in parallel for each of the plurality of solar cells 3. However, the bypass diode 10 may be connected in parallel to each of the solar cells 3. Or one bypass diode 10 for all the solar cells 3
May be connected in parallel, and the present invention can of course be applied to such a configuration.

[0038]

As described above, according to the present invention,
It is possible to minimize the damage of the bypass diode due to lightning surge, and even if the bypass diode is damaged, it is possible to prevent the bypass diode from overheating and igniting beforehand, thus ensuring safety. The effect of achieving a significant improvement in is obtained. That is, specifically, in the case where the lightning arrester is provided as in the first invention, since the lightning arrester absorbs the lightning surge,
The bypass diode is protected from lightning surge.

In the case where the thermal fuse is provided as in the second invention, after the bypass diode is short-circuited by the lightning surge, if the bypass diode is overheated by the generated current, the thermal fuse is blown. Therefore, no more current flows through the bypass diode, and ignition of the bypass diode is suppressed. Further, in the case where the current fuse is provided as in the third invention, if a current in the opposite direction is applied to the current fuse after the bypass diode is short-circuited by the lightning surge, the current fuse is blown. As a result, no current flows through the bypass diode, so that overheating and ignition of the bypass diode are prevented.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a solar cell module according to one embodiment of the present invention.

FIG. 2 is a circuit diagram showing a circuit configuration of the solar cell module according to the embodiment.

FIG. 3 is a circuit diagram showing a circuit configuration of a bypass unit of the solar cell module according to the embodiment.

FIG. 4 is a circuit diagram showing a circuit configuration of a solar cell module according to another embodiment.

FIG. 5 is a circuit diagram showing a circuit configuration of the solar cell module according to the first embodiment of the present invention.

FIG. 6 is a circuit diagram showing a circuit configuration of a solar cell module according to a second or third embodiment of the present invention.

FIG. 7 is a configuration diagram illustrating an overall configuration of a residential solar power generation system.

FIG. 8 is an external perspective view of a solar cell module.

FIG. 9 is a circuit diagram of a solar cell module according to a conventional embodiment.

[Explanation of symbols]

 Reference Signs List 3 solar cell 10 bypass diode 11 lightning arrester 12 thermal fuse 13 current fuse

Claims (5)

[Claims] 1. A solar cell module comprising a plurality of solar cells connected in series and a bypass diode connected in parallel to each or a plurality of columns of the solar cells. Is a solar cell module in which lightning arresters are connected in parallel. 2. A solar cell module in which a large number of solar cells are connected in series with each other, and a bypass diode is connected in parallel to each or a plurality of columns of the solar cells. , Wherein a thermal fuse receiving heat generated by the bypass diode is connected in series. 3. A solar cell module in which a large number of solar cells are connected in series with each other, and a bypass diode is connected in parallel to each or a plurality of columns of the solar cells. Is a solar cell module, wherein current fuses are connected in series. 4. The solar cell module according to claim 2, further comprising a display for displaying the fusing of at least one of the temperature fuse and the current fuse. 5. The solar cell module according to claim 1, wherein a temperature fuse and a current fuse are connected in series to a circuit including a bypass diode and a lightning arrester. A solar cell module, wherein an indicator is connected in parallel to a circuit including a temperature fuse, a current fuse, a bypass diode, and a lightning arrester.