JPS63289875A - Solar battery - Google Patents

Abstract

PURPOSE:To prevent a disconnection due to a vibration or the like at a connection part by a method wherein a film of a resistor is formed on a substrate and one end of the resistor is connected collectively to one part of a lower-part electrode and an upper-part electrode. CONSTITUTION:In a solar battery where individual films of lower-part electrodes 11, 22,...2n and upper-part electrodes 51, 52,...5n are formed in succession on a substrate 1, films of resistors 41, 42 are formed on the substrate 1; because these films have been formed, one end of the resistors 41, 42 is connected to at least one of the lower-part electrodes 21, 22,...2n and the upper-part electrodes 51, 52,...5n. That is to say, because at least one film of the lower-part electrodes 21, 22,...2n and the upper-part electrodes 51, 52,...5n of the solar battery and the films of the resistors 41, 42 are connected mutually while they are formed separately on the substrate 1, no soldering operation is required to connect them. By this setup, it is possible to prevent failure and disconnection due to a vibration or the like at a connection between the resistors 41, 42 and the solar battery.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a solar cell that is incorporated into, for example, a watch or the like.

(Prior Art) Conventionally, solar cells are known in which a lower electrode, a semiconductor layer, and an upper electrode are sequentially formed on a substrate.

For example, when the solar cell is mounted on a device such as a watch, if the place where the device is placed is dark and insufficient light is irradiated, the output of the solar cell will decrease, and the function of the device will deteriorate.

Therefore, in order to avoid this drop, a secondary battery is installed in addition to the solar battery, and the secondary battery compensates for the temporary drop in voltage.

When a secondary battery is provided, the backflow prevention diode, current control resistor, and secondary battery are disposed on a printed circuit board and interconnected, and the resistor and the solar cell are connected.

For example, in a solar cell for a watch, a transparent conductive electrode, an amorphous silicon semiconductor layer, and a back electrode are sequentially formed on an insulating light-transmitting substrate. This amorphous silicon semiconductor solar cell is assembled into a watch with an insulating transparent substrate facing outward1.In addition to this, a printed circuit board with a backflow prevention diode and a current control resistor element soldered to it, and a nickel-cadmium A secondary battery such as silver oxide is built into the watch and these are interconnected.

The backflow prevention diode prevents current from flowing backwards from the secondary battery to the solar cell when the solar cell is not irradiated with sufficient light and its output voltage becomes lower than the voltage of the secondary battery. Further, the current control resistor element intervenes in the connection circuit between the solar cell and the secondary battery for the following reason.

The current of a solar cell fluctuates by a factor of 11 depending on the illuminance of the light it receives. For example, a solar cell formed almost on the entire surface of a 50 mm x 50 mm substrate will draw a current of about 0.03 mA when indoor fluorescent lights (about 200 lux) are placed directly under the sunlight (about 1.0 mA).
20. QOo lux), a current of 1QIIIA flows, and if a large current flows, the secondary battery will be damaged, so to prevent this, it is necessary to suppress the current.

(Problems to be Solved by the Invention) As described above, the reliability of the current control resistor element soldered to the printed circuit board depends on the connection of the parts. For example, when soldering, the solder tends to get wet or spread poorly due to dirt on the parts, resulting in incomplete connections, and vibrations can cause poor contact or breakage of the connections/parts.

The present invention aims to solve these conventional problems.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a solar cell in which a lower electrode, a semiconductor layer, and an upper electrode are sequentially formed on a substrate. The present invention is characterized in that a body film is formed, and one end of the resistor and at least one of the lower electrode and the upper electrode are integrally connected by forming the film.

(Function) Since the film of at least one of the lower electrode and the upper electrode of the solar cell and the film of the resistor are connected to each other by being formed on the substrate, soldering is not required for the connection. Therefore, the connection between the resistor and the solar cell will not become defective or disconnected due to vibration or the like.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In Figures 1 and 2, 1 is 50+nmx50+
oIIIX 1.1 mm transparent glass substrate, 2, . 2
2-...2n is a lower electrode made of an indium tin oxide (ITO) film deposited on the glass substrate 1, and 3 is integrally deposited to cover the lower electrodes 21,22...2I). The formed amorphous silicon film, 41.4 □, is indium tin oxide (IT) deposited on the glass substrate 1.
O) The resistors 54.5□...5n made of films are upper electrodes (back electrodes) made of aluminum films formed on the amorphous silicon film 3.

The lower electrode 2. Connection part 2. a and one end of the resistor 4,
Upper electrode5. Connection part 5. Connection part 2 between a and the lower electrode 22
□A1 upper electrode 5□ connection part 52a and lower electrode 23 (
The connecting portions 23a of the upper electrodes 5n-+ (not shown) are connected to each other, and the same applies to the connecting portions 23a of the upper electrodes 5n-+ (not shown).
1-18 and the connecting portion 2na of the lower electrode 2n are connected to each other, all n power generation units are connected in series, and the connecting portion 5na of the upper electrode 5n is connected to one end of the resistor 42.

This solar cell was created as follows.

Indium tin oxide (IT) formed on the main surface of the glass substrate 1
O) Lower electrode 2. is formed by screen printing an acid-resistant resist mainly composed of rosin resin on the film. ．． 22...2n
pattern and resistor 4. ．． 42 patterns were printed and cured, and then the ITO film not covered with the resist was etched away by immersing it in an etching solution containing hydrochloric acid as a main component. Thereafter, the resist is peeled off using a commercially available stripping solution, and the lower electrodes 2, . 22
...2n and resistor 4. ．． 42 was formed.

Resistor 4. ．． 42 each has a width of 0.5 mm and a length of 20
The resistance between points P and Q with a size of mm has a value of 4 to Ω,
Resistor 4. is connected to the lower electrode 21, and the resistor 42 is formed independently. Next, resistors 4, . 42 and the lower electrodes 21.22...2n connection parts 2, a, 2□a...
Lower electrode 2 excluding the region containing 2na. ．． 22...2n
The top was continuously covered with an amorphous silicon film 3.

The amorphous silicon film 3 is made by depositing a P layer of amorphous silicon to a thickness of 100 nm using the plasma CVD method.
A layer of amorphous silicon was formed to a thickness of 5,000 layers, and an n-layer amorphous silicon was formed to a thickness of 300 layers. Next, a lower electrode 2. is formed on the amorphous silicon film 3. ．．
22...21) by vaporizing aluminum at a position opposite to the upper electrode 5. ．． 52...5n was formed.

The solar cell 6 is mounted on a third circuit board separately prepared from a backflow prevention diode 7 mounted on the circuit board and a carbon-lithium secondary battery 8 (Matsushita Battery Industries CL 2020, current capacity C-1mAh). Connect as shown. In FIG. 3, numeral 9 indicates an ammeter connected for measurement.

When the solar cell 6 is irradiated with light at an illuminance of 100,000 lux from a solar simulator (manufactured by Ushio Inc.) light source, 0.3
A current of mA flowed.

Next, the solar cell 6 was subjected to a vibration test in which the amplitude was 1.5 mm, the vibration frequency was changed from 10 Hz to 2000 Hz, and one cycle (within 20 minutes) was to return to lOH2.
, y, and z directions for 2 hours each, and then measured the output current. As a result, there was no fluctuation.

Comparative example A leaded resistor made of cylindrical porcelain with a carbon film formed and an insulating film was used, and the resistor was vibrated in the same manner and under the same conditions as the above example, except that it was connected in series with the solar cell. As a result of the test, the disconnection of the connection between the solar cell and the resistor was 1'8 ppI11.

In the above example, the resistor was made using the same ITO film as the lower electrode at the same time as the lower electrode.
It may be formed by forming a film of i-Cr or the like so that one end thereof overlaps with the connecting portion of the lower electrode.

(Effects of the Invention) As explained above, according to the present invention, since the connection between the resistor and the electrode of the solar cell does not involve soldering, the connection part will not be disconnected due to vibration etc., thereby improving reliability. It has the effect of improving.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■--■ in FIG. 1, and FIG. 3 is a connection test circuit thereof. 1... Transparent glass substrate 21.22...2n... Lower electrode 3... Amorphous silicon film 41.42... Resistor 5, . 52...5n...Outside the upper electrode 26 Fig. 1 Fig. 3

Claims (1)

[Claims] In a solar cell in which films of a lower electrode, a semiconductor layer, and an upper electrode are sequentially formed on a substrate, a film of a resistor is formed on the substrate, and by forming the film, one end of the resistor, the lower electrode, and the upper electrode are formed. A solar cell characterized in that at least one of the electrodes is integrally connected.