JPS5994880A - Solar battery - Google Patents

Abstract

PURPOSE:To increase the stability and the ratio of power generating effective area by a method wherein a solar battery element is so arranged as to surround three directions of a diode element, and the connection between the solar battery element and the diode element is performed by extending the lower and upper electrodes of each. CONSTITUTION:The solar battery element is composed of a clear electrode 41, an a-Si layer 11, and a metallic electrode 81, and the protection diode is composed of a clear electrode 42, an a-Si layer 12, and a metallic electrode 82. The reverse parallel connection between the solar battery element and the diode is performed by the contact between the metallic electrode 81 of the solar battery element and the clear electrode 42 of the diode and that between the metallic electrode 82 of the diode and the clear electrode 41 of the solar battery element. P-layers 51 and 52 of the a-Si layer do not short-circuit by the metallic electrode, the margin for mask alignment can be cut down to the minimum at the arrangement wherein the three directions of the diode are surrounded by the solar battery element, and then the ratio of effective area of the solar battery improves.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar cell in which a diode is connected in antiparallel to a thin film solar cell element.

It has been pointed out that connecting a reverse rose diode is effective for protecting solar cell elements.

An example of this is shown in FIG. They are connected in antiparallel to diodes 21 corresponding to the solar cells 1, respectively. Since the forward voltage of the diode is approximately 0.5V, the solar cell is prevented from being reverse biased in excess of 0.5V. When solar cell 1 is in a power generation state and operates in open voltage mode, diode 2 will be reverse biased, so it is important that the diode has a reverse breakdown voltage that is greater than the open circuit voltage of the solar cell. It is.

If a diode with a high reverse breakdown voltage is used, a single anti-parallel connected diode can protect a solar cell from several series-connected solar cell elements. By connecting diodes in parallel to solar cells in this way, it is possible to form a highly stable solar cell system, but incorporating diodes each time when forming a solar cell module requires assembly costs such as preparing the diodes and brazing them. There is a problem that it gets bulky.

Thin film silicon solar cells can be formed in any size and in any number of series on an insulating substrate such as a glass substrate using glue discharge properties. FIG. 2 schematically shows a method for connecting the thin film silicon solar cell 10 and the diode 20 in antiparallel. Transparent conductive film 41 on glass substrate 3
．． 42 is separated and formed. On top of that, a-8i (7 mos/L = 77 silicon) was applied using the glow discharge method.
The layers are P-type layers 51, 52.1 layers 61, 62, and n-type layer 71.
, 72 to a suitable thickness. This method of formation is well known to those skilled in the art. Next, metal electrode 81.
82' is formed by a method such as e-evaporation to create two diodes 10 and 20. A light shielding film 9 is formed on the diode 20 used as a backflow prevention diode, which can be formed by printing an opaque film such as paint. By electrically connecting the metal electrode 81 and the transparent electrode 42 and the metal electrode 82 and the transparent electrode 41 of these two diodes 10.20, the solar cell element 1o and the protection diode 20 can be connected in antiparallel. .

An object of the present invention is to provide an easy-to-manufacture and highly reliable structure of a solar cell including such anti-parallel connected diodes.

The purpose of this is to provide a solar cell element in which a lower electrode, a semiconductor layer having a junction, and an upper electrode are laminated on the same substrate, and a diode element connected in antiparallel to the solar cell element. In the case where the solar cell element is arranged so as to surround three sides of the diode element, the solar cell element and the diode element are connected by extending the lower electrode and the upper electrode of each to make contact with each other. It will be achieved by being exposed.

Embodiments of the present invention will be described below with reference to the drawings. Common parts in each figure, including FIG. 2, are given the same reference numerals. 3(a) to 3(c) are plan views showing the manufacturing process of the first embodiment of the present invention, and FIG. 4 is a sectional view taken along the line AA' in FIG. 3(e). First, an insulating substrate 3 such as a crow
Transparent electrodes 41 and 4 are placed on top of the transparent electrodes 41 and 4 as shown in FIG.
Perform 2 patterning. Next, add 1 layer of a-8i layer 5
1,1 layer61. 1- of the n layer 71, FIG. 3<b)
The a-St layers 11 and 12 are patterned as shown in FIG. Further, as shown in FIG. 3Cc), the metal electrode 81
, 82 are formed, and then the resist during patterning is removed to complete the solar cell.

A solar cell element is constituted by the transparent electrode 41, the a-81 layer 11 and the metal electrode 81, and the transparent electrode 42, the a-8 layer 1
2 and the metal electrode 82 constitute a protection diode.

Although not shown, forming an opaque film on the opposite side of the transparent electrode 42 of the transparent insulating substrate 3 is the same as in the case of FIG. The solar cell element and the diode are connected in antiparallel by the contact between the metal electrode 81 of the solar cell element and the transparent electrode 42 of the diode, and the contact between the metal electrode 82 of the diode and the transparent electrode 41 of the solar cell element.

With this configuration, even if the metal electrode patterns 81 and 82 formed on the a-8i layer are misaligned, the a-8t nine layers 51 and 9 of the solar cell element and protection diode
The n-layer 52 is no longer short-circuited by the metal electrode. Therefore, in the arrangement in which the diode is surrounded by solar cell elements on three sides, the margin for mask alignment can be minimized, and the effective area ratio of the solar cell is improved.

A second embodiment is shown in FIG. 5, and in this case, FIG. 3(b)
When forming the a-8i pattern in the process, the photoelectric conversion part 1
1 and the protection diode part 12 are not formed separately, but are made into a continuous pattern 13.

By doing so, the probability that the metal electrode 82 and the transparent electrode 42 will be short-circuited is reduced. Note that leakage caused by making the a-8i layer continuous is unlikely to become a problem in a large current region under high illuminance because the specific resistance of a-8i is large.

Figures 6(a) to 6(e) show a third embodiment in which a plurality of solar cells are connected in series, (A) is a plan view, and (b)
3A is a sectional view taken along the line BB', and FIG. 3C is a sectional view taken along the line CC'. Transparent electrode 4 provided on transparent insulating substrate 3
The pattern of is shown as a dashed line in FIG. 6(a), and the pattern of a-8i
The pattern of layers 11 and 12 is shown in dashed lines.

The transparent electrode 4 is common to the solar cell element and the protection diode, and the metal electrode 81 of the solar cell element is connected to the common electrode 4 of the next solar cell element and the protection diode, forming a series connection as shown in FIG. A combination of solar cell elements and protection diodes connected in antiparallel to each of them is realized. The light incident side of the protection diode is coated with opaque resin.
Needless to say, it blocks light.

Figure 7 is Figure 6 of the third embodiment in the fourth embodiment (
A cross section corresponding to b) is shown, and a S IM 12 is a
The a-8t layer 13 is not separated from the -8t layer 11, but is formed as an integrated a-8t layer 13. Since the surface resistance of the a-8t solar cell is small, leakage between the solar cell element and the protection diode is hardly a problem. By adopting this structure, the protective needle Z-ode can be made in the same process as making solar cells.

In addition, since one protection diode is provided for each solar cell element, the protection diode is only subjected to a reverse bias equal to the open circuit voltage of the solar cell element, and the protection diode may be destroyed by the solar cell output. Therefore, it is possible to obtain solar cells with stable output.

As described above, the present invention creates a diode for protecting a thin-film solar cell element from reverse bias in an area surrounded by the solar cell element on at least three sides in the same process as the solar cell element, and at the same time extends the electrode. The effect is extremely large, as it is possible to complete an anti-parallel connection by using the parts, and a solar cell with high stability and a large effective surface weight ratio for power generation can be obtained.

[Brief explanation of drawings]

Figure 1 is a circuit diagram in which a solar cell element and a protection diode are connected in antiparallel, Figure 2 is a schematic diagram embodying the circuit in Figure 1 in a thin film silicon element, and Figures 3 (a) to (c) are FIG. 4 is a plan view showing the manufacturing process of the first embodiment of the invention, FIG. 4 is a cross-sectional view taken along the line A-A' in FIG. FIG. 3 is a corresponding cross-sectional view. 3...Transparent insulating substrate, 4,41.42...Transparent electrode, 11°12...A-8T layer, 81.82...Metal electrode. Age 1 (21 years old 2 Figure 4175 Figure 41

Claims (1)

[Claims] 1) A solar cell element in which a lower electrode, a semiconductor layer having a junction, and an upper electrode are laminated on the same substrate, and a diode element connected antiparallel to the solar cell element are provided, and the diode element is provided with an external light source. The solar cell element is arranged so as to surround at least three sides of the diode element, and the connection between the solar cell element and the diode element is made by connecting the lower electrode and the upper electrode with each other. A solar cell characterized in that it is produced by contact.