JPH04307771A - Solar cells and solar cell modules using them - Google Patents

Abstract

PURPOSE:To wire wirings only on one surface of a solar cell and to eliminate troublesome wirings by a method wherein layers provided on the left side of the surface on one side of the surfaces of the solar cell are used as first conduc tivity type and second conductivity type semiconductor layers for constituting the solar cell and layers provided on the right side of the surface on one side are used as first conductivity type and second conductivity type semiconductor layers for protective diode. CONSTITUTION:A solar cell has first and second semiconductor layers 3 and 4 for protocurrent collection use on the rear of a solar cell substrate 12 and a protective diode is incorporated into these layers 3 and 4. The layer 3 and 4 for photocurrent collection are formed on the left side and first and second semiconductor layers 6 and 5 for the protective diode and on the right side respectively on the rear of the solar cell. Thereby, as a wiring 7 for connecting the layers 3 and 4 to each other and a wiring 8 for connecting the layers 6 and 5 to each other can be wired only one the rear of the solar cell, a wiring process can be simplified.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell and a solar cell module using the same, and more particularly to a solar cell having a protection diode and a solar cell module using the same.

0002

2. Description of the Related Art Conventionally, a solar cell module in which a plurality of solar cells are connected is constructed by connecting a solar cell 1 and a protection diode (bypass diode) 2 in antiparallel, as shown in FIG. 1(a). The structure was such that even if any of the solar cells stopped generating power during power generation by the incident light 10, current would flow through the protection diode and the solar cell module would be able to continue generating power. This protection diode was generally formed separately from the solar cell.

On the other hand, the solar cell module described in Japanese Patent Application Laid-Open No. 57-122580 combines a pair of solar cells and a protection diode into one element as shown by the broken line, as shown in FIG. 1(b). It had a structure that could be built inside. FIG. 2 is a schematic cross-sectional view of a solar cell used in this. A first semiconductor layer 3 for collecting photocurrent and a second semiconductor layer 4 of a different conductivity type constituting a solar cell are formed on the front and back surfaces of a solar cell substrate 12, respectively. The first semiconductor layer 6 for a protection diode constitutes a protection diode with the second semiconductor layer 4 described above. The wiring 7 connects the second semiconductor layer 4 for photocurrent collection and the first semiconductor layer 3' of the adjacent solar cell. Further, the wiring 8 connects the first semiconductor layer 6 for a protection diode and the second semiconductor layer 5' for a protection diode of an adjacent solar cell. Furthermore, similar wiring connections are repeated for other solar cells.

0004

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, since semiconductor layers of different conductivity types are formed on the front and back surfaces of the solar cell, wiring for connecting a plurality of solar cells is difficult to achieve. There was a problem that the wiring was complicated since it was done on the front and back sides.

An object of the present invention is to provide a solar cell in which wiring can be performed only on one side of the solar cell. Another object of the present invention is to provide a solar cell module using such a solar cell.

[0006]

[Means for Solving the Problems] The above object is to provide (1) a semiconductor substrate, a semiconductor layer of a first conductivity type and a semiconductor layer of a second conductivity type provided on one surface of the substrate for constituting a solar cell; (2) A solar cell comprising a semiconductor layer of a first conductivity type for a protection diode and a second conductivity type semiconductor layer provided on one surface of the solar cell, (2) described in 1 above. In the solar cell, the protection diode is
(3) A solar cell comprising a semiconductor layer of a first conductivity type for the protection diode and a semiconductor layer of a second conductivity type for forming the solar cell;
Or, in the solar cell according to 2, the semiconductor layer of the second conductivity type for forming the solar cell is electrically connected to the semiconductor layer of the second conductivity type for the protection diode. (4) A solar cell according to 1, 2 or 3 above.
In the solar cell described above, one end of one surface of the substrate is formed with at least a semiconductor layer of a first conductivity type for forming the solar cell and a semiconductor layer of a second conductivity type for the protection diode. At least a second conductivity type semiconductor layer for forming the solar cell and a first conductivity type semiconductor layer for the protection diode are formed on the end of one surface of the substrate opposite to the one end. (5) a semiconductor substrate; a first semiconductor layer of a first conductivity type and a second conductivity provided on one surface of the substrate to constitute the solar cell; A solar cell comprising a second semiconductor layer of a type and a third semiconductor layer of a first conductivity type provided on one surface of the second semiconductor layer to constitute a protection diode, 6) In the solar cell according to 5 above, at least the first semiconductor layer is formed on one end of one surface of the substrate, and at least the second semiconductor layer is formed on the end opposite to the one end of the one surface of the substrate. This is achieved by a solar cell characterized in that the third semiconductor layer and the third semiconductor layer are formed.

Another object of the above is (7) having a plurality of solar cells according to any one of 1 to 4 above, wherein the semiconductor layer of the first conductivity type for forming the solar cells of the solar cells is , a solar cell module characterized in that it is electrically connected to a semiconductor layer of a second conductivity type for forming a solar cell of an adjacent solar cell, (8) the solar cell module according to 7 above, The semiconductor layer of the second conductivity type for the protection diode of the solar cell is electrically connected to the semiconductor layer of the first conductivity type for the protection diode of the adjacent solar cell. Battery module, (
9) A solar cell comprising a plurality of solar cells according to 5 or 6 above, wherein the first semiconductor layer of the solar cell is electrically connected to the second semiconductor layer of an adjacent solar cell. Module (10) In the solar cell module as described in 9 above, the third semiconductor layer is electrically connected to the second semiconductor layer of the adjacent solar cell. Ru.

[0008]

[Operation] The operation of the present invention will be explained using the drawings. FIG. 3 is a schematic diagram of an example of the solar cell of the present invention. A first semiconductor layer 3 and a second semiconductor layer 3 for photocurrent collection are provided on the back surface of the solar cell substrate 12.
The semiconductor layer 4 has a semiconductor layer 4 in which a protection diode is built. A bottom view of this structure is shown in FIG. On the back side of the solar cell, a first semiconductor layer 3 and a second semiconductor layer 4 for photocurrent collection are on the left side of the figure, and a first semiconductor layer 6 and a second semiconductor layer 5 for a protection diode are on the left side of the figure. are formed on the right side of each. As a result, the wiring 7 for connecting the semiconductor layer for photocurrent collection and the wiring 8 for connecting the semiconductor layer for the protection diode can be wired only on the back side of the solar cell, thereby simplifying the wiring process. .

[0009] In a typical solar cell, electrodes are connected to some or all of the above semiconductor layers, and the above wiring is often connected through these electrodes, but for the sake of brevity, Explanation of the electrodes is omitted.

Further, FIGS. 5(a) and 5(b) show bottom views of other examples of solar cells. As can be seen in the figure, the shapes of the first semiconductor layer 3 and second semiconductor layer 4 for photocurrent collection and the first semiconductor layer 6 and second semiconductor layer 5 for protection diode are various shapes. There may be. Further, on the surface where the first semiconductor layer 3 and the second semiconductor layer 4 of the solar cell are formed,
Sub-patterns 11 may be formed and semiconductor layers or electrodes (not shown) for photocurrent collection may be connected to these sub-patterns 11. In still another example, as shown in FIG. The semiconductor layer 6 may be formed.

Next, the function of the protection diode will be explained. In FIG. 7, an n-type semiconductor is used for the solar cell substrate 12,
2 is a schematic diagram of a solar cell in which the first semiconductor layer 3 is a p-type emitter and the second semiconductor layer 4 is an n-type collector 4. FIG. If the solar cell at the bottom of the diagram stops generating electricity, the current will be 9
is the second semiconductor layer (collector) 4' of the lower solar cell
, through the solar cell substrate 12', the second semiconductor layer (collector) 5' for the protection diode, to the first semiconductor layer (emitter) 6 for the protection diode of the upper solar cell, and then this first semiconductor layer (emitter) 6 for the protection diode of the upper solar cell. into the upper solar cell through a protection diode consisting of a semiconductor layer (emitter) 6 and a second semiconductor layer (collector) 4 for photocurrent collection. Therefore,
Even if some of the solar cells stop generating power during operation of a solar cell module configured by connecting a large number of solar cells in series, current will flow in a detour.

[0012] As is clear from the above explanation, it is necessary that the resistance be sufficiently low between the second semiconductor layer (collector) for collecting light and the second semiconductor layer (collector) for protecting diode. It is. For this purpose, it is desirable that these semiconductor layers be connected by an electrode with as low resistance as possible or a semiconductor layer of the same conductivity type.

Next, FIG. 8 shows a solar cell in which a p-type semiconductor is used for the solar cell substrate 12, the first semiconductor layer 3 is an n-type emitter, and the second semiconductor layer 4 is a p-type collector. The function of the protection diode will be explained using the following. When the lower solar cell in the figure stops generating power, the current 9 is transferred to the second semiconductor layer (collector) for photocurrent collection of the upper solar cell.
4 flows into the lower solar cell through a protection diode consisting of this second semiconductor layer 4 and a first semiconductor layer (emitter) 6 for the protection diode, It flows to the next solar cell through the second semiconductor layer (collector) 5', the solar cell substrate 12', and the second semiconductor layer (collector) 4' for photocurrent collection.

[0014]

[Embodiment] An embodiment of the present invention will be described with reference to FIG. For the solar cell substrate 12, n-type single crystal Si was used. The first layer, which is a p-type emitter, is formed on the back side of this substrate by ordinary phosphorus diffusion.
Semiconductor layers 3 and 6 were formed, and second semiconductor layers 4 and 5, which were n-type collectors, were formed by boron diffusion. At the same time, in order to increase photocurrent collection efficiency, sub-patterns 11 connected to the semiconductor layer for photocurrent collection were formed with impurities of respective conductivity types at the same time as described above. 2nd for photocurrent collection
The semiconductor layer 4 and the second semiconductor layer 5 for protection diode are as follows:
In order to reduce the resistance between them, they are connected by a part of a sub-pattern 11 made of a semiconductor layer of the same conductivity type. Next, A1 electrodes 13 were formed on the surfaces of the semiconductor layers. As a result, when connecting multiple solar cells, it is only necessary to connect the wiring 7 and the protective diode wiring 8 to the back side of the solar cells in parallel as shown in the figure, which greatly simplifies the process.

[0015] Note that the protection diode formed on the same substrate as the solar cell at one end of the solar cell array constituting the solar cell module is not used. Furthermore, it is necessary to attach one protection diode externally to the solar cell at the other end of the row.

Although the above embodiments have been explained using an n-type substrate, the same can be said for using a p-type substrate or an i-type substrate. Furthermore, it goes without saying that the substrate may be made of a single crystal, polycrystal, microcrystal, or amorphous semiconductor material. Furthermore, the substrate material is GaAs, InP, CIS
, CdS, CdTe, AIGaAs, or other materials having photoelectric conversion properties may be used. Further, the incident light 10 may be incident from the back surface of the solar cell.

[0017]

[Effects of the Invention] By using the present invention, the modularization process can be greatly simplified because wiring is required only on one side of the substrate as described above. Further, in the case of the above embodiment, since the wiring between the solar cells and the wiring for the protection diode can be connected in parallel in the same manner, there is no need to perform complicated wiring for connecting the protection diode.

[Brief explanation of drawings]

FIG. 1 is an equivalent circuit diagram of a solar cell and a protection diode.

FIG. 2 is a schematic cross-sectional view of a conventional solar cell.

FIG. 3 is a schematic diagram of a solar cell according to an embodiment of the present invention.

FIG. 4 is a bottom view of a solar cell according to an embodiment of the present invention.

FIG. 5 is a bottom view of a solar cell according to another embodiment of the present invention.

FIG. 6 is a bottom view of a solar cell according to still another embodiment of the present invention.

FIG. 7 is a schematic diagram for explaining the current path of the solar cell of the present invention.

FIG. 8 is a schematic diagram for explaining the current path of the solar cell of the present invention.

FIG. 9 is a bottom view of a solar cell according to an example of the present invention.

[Explanation of symbols]

1 Solar cell 2 Protection diode 3, 3', 6, 6' First semiconductor layer 4, 4', 5,
5' Second semiconductor layer 7, 8 Wiring 9 Current path 10 Incident light 11 Sub-pattern 12, 12' Solar cell substrate 13 Al electrode

Claims (10)

[Claims] Claims: 1. A semiconductor substrate, a semiconductor layer of a first conductivity type and a semiconductor layer of a second conductivity type provided on one surface of the substrate for configuring a solar cell, and a semiconductor layer provided on the one surface of the substrate. Furthermore, a solar cell comprising a semiconductor layer of a first conductivity type and a semiconductor layer of a second conductivity type for a protection diode. 2. The solar cell according to claim 1, wherein the protection diode includes a semiconductor layer of a first conductivity type for the protection diode and a semiconductor layer of a second conductivity type for forming the solar cell. A solar cell characterized by comprising: 3. The solar cell according to claim 1 or 2, comprising:
A solar cell characterized in that the second conductivity type semiconductor layer for forming the solar cell is electrically connected to the second conductivity type semiconductor layer for the protection diode. 4. The solar cell according to claim 1, wherein one end of one surface of the substrate includes at least a semiconductor layer of a first conductivity type for forming the solar cell and a semiconductor layer for forming the protection diode. A semiconductor layer of a second conductivity type for forming the solar cell is formed, and an end opposite to the one end of one surface of the substrate is formed with a semiconductor layer of a second conductivity type for forming the solar cell and a semiconductor layer of the protection diode. A solar cell characterized in that a semiconductor layer of a first conductivity type is formed. 5. A semiconductor substrate, a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and the second semiconductor layer provided on one surface of the substrate to constitute a solar cell. A solar cell comprising a third semiconductor layer of a first conductivity type provided on one surface of the semiconductor layer to constitute a protection diode. 6. The solar cell according to claim 5, wherein at least one end of one surface of the substrate is formed with at least the first semiconductor layer, and an end of one surface of the substrate opposite to the one end is formed with at least one end of one surface of the substrate. A solar cell comprising the second semiconductor layer and the third semiconductor layer. 7. A plurality of solar cells according to claim 1, wherein the semiconductor layer of the first conductivity type for constituting the solar cell is a semiconductor layer of the adjacent solar cell. A solar cell module characterized in that it is electrically connected to a second conductivity type semiconductor layer for forming a solar cell. 8. The solar cell module according to claim 7, wherein the second conductivity type semiconductor layer for the protection diode of the solar cell is a semiconductor layer of the first conductivity type for the protection diode of the adjacent solar cell. A solar cell module characterized by being electrically connected to a layer. 9. A solar cell comprising a plurality of solar cells according to claim 5 or 6, wherein the first semiconductor layer of the solar cell is electrically connected to the second semiconductor layer of an adjacent solar cell. solar cell module. 10. The solar cell module according to claim 9, wherein the third semiconductor layer is electrically connected to the second semiconductor layer of the adjacent solar cell.