JP2011040695A - Panel for solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a reverse voltage arising between some cells and the other ones when the efficiency of photovoltaic power generation of the solar cell panel decreases for some cells in the shaded area to result in reduction of the entire photovoltaic power of the solar cell battery panel need be prevented in the prior art, by mounting a bypass diode to each of columns of the existing cells. <P>SOLUTION: In the solar cell panel, a bypass diode can be accommodated in each gap of cells, have a thickness lower than the maximum height of the bus bar, and can be connected to the existing wiring line of the bus bar. As a result, the bypass diode can be easily mounted economically. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bypass diode for a solar cell.

In recent years, it is predicted that global warming will occur due to the greenhouse effect due to the increase in CO2, and the demand for solar cells as clean energy is rapidly spreading.
In the case of power generation using a normal solar battery, since the output is low with only one solar battery cell (solar battery element), it is necessary to increase the voltage by connecting a plurality of solar battery cells in series.
Thus, a solar cell panel is produced by creating a plurality of rows of solar cells (hereinafter referred to as cells) connected in series and connecting them in parallel to increase the current.

However, if multiple cells are used, if one cell in the cell line that connects multiple cells in series is not able to generate power due to shadows of the building or partial malfunction of the cell, etc. When the voltage generated from the other cells becomes a reverse voltage and exceeds the breakdown voltage of the cell, the cell may be destroyed. In addition, since one cell no longer generates power, power generation of the entire cell array connected in series is hindered.
Therefore, in order to prevent the generation of the reverse voltage and the inhibition of the power generation, the diodes are connected in parallel so that the reverse voltage is not generated with respect to the cell strings connected in series. This type of diode is called a bypass diode. Generally, one place is used for a cell row in which a plurality of cells are connected in series. Each series of cells connected in series is set so as not to generate a reverse voltage, and a solar cell panel is manufactured by connecting them in parallel to increase the current.

However, if a bypass diode is attached to each cell, reverse voltage for each cell can be prevented. Therefore, even if only one cell has a problem due to shadows, etc., the power generation of the entire cell string connected in series is not hindered, and the reverse voltage of only one cell is prevented by preventing other voltages. The power generation of the cell can be utilized.
Such a conventional example is shown in Japanese Patent Laid-Open No. 2000-196128 shown in FIG.

FIG. 7 will be described. Solar cell 90 is connected by bus bar 92 so that each cell 90 is in series. As shown in the XX ′ cross-sectional view, the bus bar 92 is connected to the upper surface of the cell 90 and collects the positive-side electricity generated by the cell 90 and is connected from the surface of the cell 901 to the back surface of the cell 902 and connected in series. Tied.
By repeating such series connection in sequence, the voltage is increased and a predetermined power can be obtained. A bypass diode 91 is connected to the negative side of the back surface of the cell 90, and the bypass diode 91 is connected to be bypassed to the negative side of the adjacent cell 90.
For example, it is assumed that some troubles such as shade in the cell 902 occur and power generation cannot be performed, and no voltage is generated. Then, the bypass diode 912 is configured to pass the voltage of the cell 901 directly to the cell 903 without passing through the cell 902.

Thus, the cell 903 forms a circuit connected in series with the bus bar 921 via the bypass circuit 932 without generating a reverse voltage in the cell 902. With the configuration as described above, each cell 90 is protected so that power generation of the entire cell row 99 is not hindered.
In addition, a surface material 95 such as glass is placed on the surface of the cell row 99 connected in series, and the top surface of the cell row 99 is sealed with a surface sealing 96, and the lower surface of the cell row 99 is sealed with a back surface sealing material. Sealed at 97, and a backside material such as a plastic board is attached to the lowermost surface so that the cell array 99 is not damaged even when exposed to wind and rain outdoors, and does not deteriorate over a long period of time. Yes.
Such a method is a highly efficient solar cell panel by attaching a bypass diode 91 to each cell 90.

JP 2000-196128 A

If it is a conventional method, a dedicated electrode pattern is required for the solar battery cell 90 and cannot be used for the existing cell 20 according to the present invention. The conventional method is a bypass diode 91 that is attached to a dedicated cell 90 and is not versatile.
Next, since the attachment portion of the bus bar 92 that has become wide due to the attachment of the bypass diode 91 is located on the upper surface portion of the cell 90, the light receiving portion of the cell 90 is narrowed. Even if the bus bar 92 is attached to the outside of the cell 90 in order to widen the light receiving portion, the overall size of the solar battery panel is increased.
Further, since the bus bar 92 is attached to one side of the light receiving portion, the current collection efficiency of the electrode pattern is poor, and the current collection efficiency is inferior to that of the existing structure in which the bus bar 25 is attached to the center portion.

  Since the conventional bypass diode 91 is attached to the back surface of each cell 90, after the bypass diode 91 protrudes in the back surface direction and is laminated by the surface sealing material 96 and the back surface sealing material 97, a process of removing bubbles and soot is performed. When the surface material 95 and the back material 98 are pasted to complete a solar cell panel, the pressure is concentrated on the protruding portion of the bypass diode 91 and the cell 90 may be damaged.

  The cell 20.90 generally has a thickness of about 200 microns and is damaged by a slight one-load. Even a part of the damaged solar cell panel is discarded, resulting in a significant loss.

A plurality of solar cell elements, a connection part having a gap for connecting the one solar cell element and another solar cell element, and an upper electrode and a lower electrode of the solar cell element via the connection part A bus diode to be connected; and a bypass diode electrically connected to the bus bar at the connection portion; a positive electrode of the bypass diode is connected to the bus bar connected to an upper electrode of the solar cell element; The negative electrode of the diode provides a solar cell panel in which the bus bar is connected to the lower electrode of the solar cell element connected to the upper electrode of the solar cell element.

  Even when the solar cell elements are connected by a plurality of the bus bars, one bypass diode is connected to one bus bar to prevent generation of reverse voltage, and the bypass diode is connected to the solar cell element. It is made thinner than the thickness which connected the said bus-bar, The said bypass diode is provided in the gap | interval of the said one solar cell element and another solar cell element, It provides the solar cell panel characterized by the above-mentioned. is there.

The proposed bypass diode 30 as described above is formed so as to enter the gap in the series connection direction of each solar cell (solar cell element) 20, and is connected to the upper slope 251 of the bus bar 25 and the electrode 202 on the back surface of the cell 20. Therefore, it is not necessary to increase the space of the entire solar cell panel for the bypass diode 30 without reducing the light receiving portion of the cell 20.
In addition, since the bypass diode 30 is formed so that it can be directly connected to the electrode pattern of the existing cell 20 that is currently mass-produced, it is not necessary to make a new dedicated cell like the conventional cell 90.

  Since the bypass diodes 30 can be disposed so as to be embedded in the gaps E in the series connection direction of the solar battery cells 20, there are no protruding portions in the cell row 19, so that the cells 20 are not damaged during the lamination process, and the production efficiency is improved. I can give you.

The cell 20 has a characteristic that the power generation efficiency decreases when the temperature becomes high.
Although heat is generated when the bypass diode 30 is operating, the heat generated by the bypass diode 30 is not directly transmitted to the cell 20 by being embedded in the gap between the cells 20, and the power generation efficiency of the cell 20 is not deteriorated. It was.

  Since each cell 20 is not subjected to edge processing, there is a possibility that current flows when the edge portion of the cell 20 contacts the bus bar 25 or the adjacent cell 20. Therefore, by embedding the bypass diode 30 coated with resin or the like in the gap E of each cell 20, the bypass diode 30 coated with resin is interposed in the gap E in the series connection direction of each cell to prevent a short circuit accident. I can do it.

Since the maximum thickness H of the bypass diode 30 is lower than or equal to the maximum thickness F including the cell 20 and the bus bar 25, there is no protrusion, and it is sandwiched between glass and plastic plates after lamination. However, the load is not offset and the cell 20 is not damaged.
Moreover, the solar cell panel can be manufactured with the same thickness as the current situation.
Since the body width G of the bypass diode 30 is narrower than the gap E between the cells 20, it is possible to prevent contact between the cells 20 without affecting the light receiving portion.

It is the figure which attached the series connection and bypass diode of the photovoltaic cell which is the Example of this invention. It is a figure of the bypass diode of the Example of this invention. It is the state of the existing bus bar which has not attached the bypass diode. It is the state of the serial connection of the existing photovoltaic cell which has not attached the bypass diode. It is a figure of the prior art example which attached the bypass diode.

  In order to obtain the effects described in the above “Effects of the Invention” of the present invention, the bypass diode 30 according to the present invention is configured to be installed between the gaps E of the respective cells (solar cell elements) 20. Most effective.

  The structure of the cell (solar cell element) 20 used in the solar cell panel will be described with reference to FIGS. The upper surface portion of the cell 20 receives sunlight and generates electric power. The photovoltaic power generated in this manner is collected by the positive electrode 201 of the cell of the electrode pattern 205 printed in a lattice pattern on the surface of the cell 20. Similarly, a negative electrode 202 of the cell is printed on the back side of the cell 20.

  The photovoltaic power is supplied to the negative electrode 202 of the next cell connected in series through the bus bar 25 connected to the positive electrode 201 of the cell. As shown in FIG. 3, the bus bar 25 is connected in series from the positive electrode 201 of the cell to the negative electrode 202 of the cell on the back side of the adjacent cell via the inclined portion 250 of the bus bar.

3 and 4 are exaggerated, the thickness of the existing bus bar 25 is 200 microns, the thickness of the cell 20 is also 200 microns, the printed cell plus / minus electrodes 201.202, the solder layer, etc. The thickness is about 20 microns.
Accordingly, the maximum bus bar height F is about 600 to 700 microns. This bus bar maximum height F is the most protruding portion in the cell row 21.

  The gap E between the cells 20 is generally about 2 mm. The voltage rises due to the cell rows 21 connected in series as described above, and the overall current rises by making several cell rows 21 in parallel.

  The cells 20 connected and arranged as described above are laminated by the front surface sealing material 96 and the back surface sealing material 97. As a result, the bus bar 25 and the cell 20 are sealed so as not to deteriorate due to contact with air. A surface material 95 that allows light to pass through is attached to the surface of the cell 20 thus sealed, and a back material 98 is attached to the back surface so that the cell 20 is not damaged by pressure or bending, thereby producing a solar cell panel. Is done.

However, when one cell 20 is shaded and no photovoltaic power is generated, a reverse voltage is generated, and power generation of the entire cell array 21 connected in series is hindered. Therefore, it is necessary to attach a diode at an appropriate position such as for each cell row 21 so that power generation in other cell rows 21 is not hindered by the reverse voltage.
However, the shape of the diode increased as the power increased, and it had to be housed in a plastic case or the like and attached to the back of the solar cell panel, etc., increasing the overall thickness. It also generates heat when the diode is operating. The cell 20 is preferably installed at a position as far away from the cell 20 as possible because the photovoltaic power generation efficiency decreases at a high temperature.

  Therefore, an efficient solar panel can be manufactured by attaching a bypass diode 30.91 for each cell 20.90 as described in the conventional example.

  Next, the bypass diode 20 according to the present invention will be described with reference to FIG. The diode body 301 is formed in a rectangular shape with a width I of 2 mm or less so that the diode body 301 fits in the gap F of the cell 20. Further, by making the diode body 301 rectangular, there is an effect of increasing the current-carrying portion of the diode and improving the processing capability.

A plus metal foil electrode 302 is connected to the upper part of the diode body 301 so as to be energized, and similarly, a minus metal foil electrode 303 is connected to the lower part of the diode body 301 so as to be energized.
The plus electrode 302 is deformed so as to be twisted and connected so as to energize the bus bar inclined upper portion 251. The minus metal foil electrode 303 is connected to the minus electrode 202 of the cell so as to hold the entire bypass diode 30.

  The bypass diode 30 connected as described above is laminated with the sealing material 96.97 together with the cell array 21 after connection, and when the solar cell panel is completed, the side surface state as shown in FIG. The size is such that it fits within the maximum height F and gap E of the bus bar 25.

  As described above, the diode height H of the bypass diode 30 does not exceed the maximum height F of the bus bar, and since the diode body width I is smaller than the gap E of the cell 20, the laminating process becomes easy. This creates a synergistic effect that can be easily connected to the cell 20.

  The positive metal foil electrode 302 of the bypass diode 30 is twisted along the bus bar inclined portion 250 and connected to the upper portion of the bus bar slope. Next, the minus metal foil electrode 303 has an L shape, and is configured to be connected to the minus electrode 202 of the cell from the lateral direction as shown in FIG.

  With the minus metal foil electrode 303 having such a shape, the bypass diode 30 can be easily connected to the minus electrode 202 of the cell by soldering. Further, the plus metal foil electrode 302 is connected to the bus bar slope upper portion 251 by solder.

The minus metal foil electrode 303 can also be connected in the same rectangular shape as the plus metal foil electrode 302. However, if the metal foil electrode 303 comes into contact with the bus bar 25 during the soldering operation, the bypass diode 30 cannot function because of a short circuit. .
Further, the plus metal foil electrode 302 and the minus metal foil electrode 303 are generally connected by soldering, but the influence of heat is not concentrated by taking the distance of the solder part as much as possible.

  As described above, the solar cell panel is produced in a state where the bypass diode 30 is accommodated in the gap E between the cells 20 as shown in FIG. Even when the bypass diode 30 is activated to generate heat, since there is a gap, heat is not directly conducted to the cell 20, so that the photovoltaic generation efficiency is not lowered.

  In addition, the bypass diode 30 according to the present invention is not a bypass diode with a large processing capability attached to the cell array 21 as in the conventional example, but the bypass diode 30 according to the present invention is small and generates a small amount of heat. Further, since it is not directly attached to the back surface of the cell 90 as in the conventional example shown in FIG. 5, the photovoltaic power generation efficiency of the cell 20 is hardly reduced by heat generation.

  Further, the bypass diode 30 is coated with a resin material or the like that does not conduct electricity other than the solder portions (connection portions) of the plus metal foil electrode 302 and the minus metal foil electrode 303 to prevent deterioration and keep the heat conductivity low. be able to.

Generally, the cell 20 is used in a cutting state in which edge processing is not performed. Therefore, when a current passing through the cutting unit is touched, a current flows there. If the bypass diode 30 is coated with a resin and only the positive metal foil electrode 302 and the negative metal foil electrode 303 are not energized, the cell 20 that is not edge-treated will not be energized even if it contacts the bypass diode 30.
If the bypass diode 30 is resin-coated, it can be used as a buffer material that prevents contact and maintains a uniform interval by interposing in the gap between the cells 20.

Next, the function of the bypass diode 30 will be described with reference to FIG. When the bypass diode 30 is not activated, the current from the cell 20 on the right is first energized from the bus bar 25a to the cell 20a via the negative electrode 202a of the cell.
Next, the current together with the photovoltaic power of the cell 20a is collected at the positive electrode 201a of the cell and wired in series from the bus bar 25a to the left cell 20b via the bus bar 25b.

  However, when some trouble occurs in the cell 20a, the current transmitted from the bus bar 25a is transmitted to the minus metal foil electrode 303a of the bypass diode 30 through the minus electrode 202a of the cell. The current transmitted to the negative metal foil electrode 303a is transmitted to the bus bar 25b from the upper portion 251a of the bus bar via the positive metal foil electrode 302a via the diode body 301a and directly connected to the next cell 20b.

  As a result, the cell 20a having inferior photovoltaic power generation efficiency can be bypassed to allow a current to flow, and a decrease in the photovoltaic power of the entire solar battery panel can be minimized. Further, the bypass diode 30 can also prevent the reverse voltage generated from the bus bar 25b when the cell 20a is not energized.

  As for the number of such bypass diodes 30 used, two bypass diodes 30 may be attached to each of the cells 20 with respect to the two bus bars 25 as shown in FIG. A plurality of bus bars 25 are attached in order to increase the current collection efficiency on the surface of the cell 20.

  Even if there are a plurality of bus bars 25, it is not always necessary to install as many bypass diodes 30 as the number of bus bars 25. If they are attached to one bus bar 25, the above-described bypass circuit function can be formed. However, it is necessary to use a bypass diode 30 having a processing capability corresponding to the power.

  By the proposed bypass diode 30 as described above, the solar cell 20 is formed so as to enter the gap in the series connection direction, and is set to be connected to the upper slope 251 of the bus bar 25 and the electrode 202 on the back surface of the cell 20. Therefore, it is not necessary to increase the space of the entire solar cell panel for the bypass diode 30 without reducing the light receiving portion of the cell 20.

In addition, since the bypass diode 30 is formed so that it can be directly connected to the electrode pattern of the existing cell 20 that is currently mass-produced, it is not necessary to make a new dedicated cell like the conventional cell 90. Moreover, a solar cell panel thinner than the conventional product can be produced.
Moreover, it is more efficient and efficient to install the bus bar 25 in the central part of the cell 20 as much as possible.

  Since the bypass diode 30 can be disposed so as to be embedded in the gap E in the series connection direction of each cell 20 of the solar battery, the cell row 19 has no protruding portion, and the cell 20 is not damaged by a compressive force or the like at the time of lamination. , Increase production efficiency. A width of 2 millimeters and a thickness of 600 to 700 microns or less can be used for most current products.

The cell 20 has a characteristic that the power generation efficiency decreases when the temperature becomes high.
Although heat is generated when the bypass diode 30 is operating, the heat generated by the bypass diode 30 is not directly transmitted to the cell 20 by being embedded in the gap between the cells 20, and the power generation efficiency of the cell 20 is not deteriorated. It was.

  Since each cell 20 is not subjected to edge processing, there is a possibility that current flows when the edge portion of the cell 20 contacts the bus bar 25 or the adjacent cell 20. Therefore, by embedding the bypass diode 30 coated with resin or the like in the gap E of each cell 20, the bypass diode 30 coated with resin is interposed in the gap E in the series connection direction of each cell to prevent a short circuit accident. I can do it.

Since the maximum thickness H of the bypass diode 30 is lower than or equal to the maximum thickness F including the cell 20 and the bus bar 25, there is no protrusion, and it is sandwiched between glass and plastic plates after lamination. However, the load is not offset and the cell 20 is not damaged.
Moreover, the solar cell panel can be manufactured with the same thickness as the current situation.
Since the main body width G of the bypass diode 30 is narrower than the gap E between the cells 20, it is possible to prevent contact between the cells 20 without affecting the light receiving portion.

  Since the plus metal foil electrode 302 and the minus metal foil electrode 303 are simply attached by soldering, the mounting method is simple.

  The bypass diode 30 of the present invention can be applied to prevent the generation of reverse voltage of not only solar cells but also batteries and storage batteries.

20 cells (solar cell elements)
20a cell 20b cell 201 cell positive electrode 201a cell positive electrode 202 cell negative electrode 202a cell negative electrode 205 electrode pattern 21 cell row 25 bus bar 250 bus bar inclined portion 251 bus bar slope upper portion 251a bus bar slope upper portion 25a bus bar 25b bus bar 30 bypass Diode 301 Diode body 301a Diode body 302 Plus metal foil electrode 302a Plus metal foil electrode 303 Minus metal foil electrode 303a Minus metal foil electrode E Gap F Maximum height of bus bar H Diode height I Diode body width 90 cells (sun of conventional example) Battery cell)
901 cells (conventional example)
902 cells (conventional example)
903 cells (conventional example)
91 Bypass diode (conventional example)
911 Bypass diode (conventional example)
912 Bypass diode (conventional example)
913 Bypass diode (conventional example)
92 Busbar (conventional example)
921 Bus bar (conventional example)
922 Bus bar (conventional example)
923 bus bar (conventional example)
93 Bypass circuit 931 Bypass circuit 932 Bypass circuit 933 Bypass circuit 95 Surface material 96 Surface sealing material 97 Back surface sealing material 98 Back surface material 99 Cell array (conventional example)

Claims (4)

A plurality of solar cell elements, and a connecting portion having a gap for connecting the one solar cell element and another solar cell element;
A bus bar for connecting the upper electrode and the lower electrode of the solar cell element via the connecting portion;
A bypass diode electrically connected to the bus bar at the connection portion;
A positive electrode of the bypass diode is connected to the bus bar connected to the upper electrode of the solar cell element, and a negative electrode of the bypass diode is connected to the upper electrode of the solar cell element. A solar cell panel connected to a lower electrode.   The reverse voltage is prevented from being generated by connecting one bypass diode to one bus bar even when the solar cell elements are connected by a plurality of the bus bars. Solar panel.   The solar cell panel according to claim 1, wherein the bypass diode is made thinner than a thickness in which the bus bar is connected to the solar cell element.   The solar cell panel according to claim 1, wherein the bypass diode is installed in a gap between the one solar cell element and another solar cell element.