JPH0582035B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a secondary battery that is charged using light such as sunlight or a fluorescent lamp.

Conventional technology Batteries that use light energy such as sunlight,
Single crystal silicon, amorphous silicon (hereinafter referred to as a-
Products using semiconductors such as Si (abbreviated as Si) and CdS are available. All of these batteries that utilize photovoltaic power are primary batteries and can only be used when exposed to light. Therefore, for example, when applying solar cells to equipment that operates even at night,
A new capacitor or secondary battery will be required to charge the output of the solar cells during the day.

Problems to be Solved by the Invention Hitherto, there has been no single device that combines the function of using light energy as a primary battery and the charging function of a secondary battery.

Means for Solving the Problems The following battery is constructed in which an electrode active material is provided on one side of each of two semiconductor layers having photovoltaic force, and the two active materials are brought into contact with an electrolyte.

Effect When using the above battery configuration during the day,
The photovoltaic force of the semiconductor layer is utilized by applying a load between the first and second electrodes and between the third and fourth electrodes (primary battery action), and the first and fourth electrodes are placed in a closed circuit state. The active material can be charged with surplus photovoltaic power. When using at night, the second
By applying a load to the electrode and the third electrode, the active material can be discharged and used as a secondary battery.

Examples Example 1 As shown in Fig. 1, an ITO transparent electrode 2 (may be made of In ₂ O ₃ , SnO ₂ , ITO, Au, etc.) as a first electrode is placed on a glass transparent substrate 1 (may be made of plastic). A semiconductor layer 3 of a-Si (a-SiC(p)/a-Si(i)/a-Si(n)) having a photovoltaic force is provided thereon.
I and n are provided in this order, and Al is further deposited as a conductive layer with good ohmic contact to form a second electrode.
Note that Al/Cr, Al/Au, Au, etc. may be used instead of Al. Furthermore, a transition metal oxide WO ₃ is laminated as the first active material layer 5 .

On the other hand, similarly, a transparent electrode 10 as a fourth electrode is provided on a transparent substrate 11, and a-Si semiconductor layer 9, a conductive layer 8 as a third electrode, and a second active material layer 7 (iron-cyano complex , Ir(OH) _x , Ni(OH) _x , partially reduced transition metal oxide, etc.). However, the semiconductor layer 9 is provided in the order of n, i, and p. Finally, the two active materials are assembled in such a way that they are in contact with an electrolyte (Li salt-based propylene carbonate solution).

Now, when the substrate was irradiated with light from both sides, an electromotive force of about 0.5V was obtained between the first and second electrodes and between the third and fourth electrodes. At this time, if the second and third electrodes were kept in a closed circuit state, about twice the output voltage (about 1V) was obtained between the first and fourth electrodes.

Next, the second and third electrodes are brought into an open circuit state, and the first and third electrodes are brought into an open circuit state.
When the fourth electrode is placed in a closed circuit state, a charging current flows with the fourth electrode as the positive electrode and the first electrode as the negative electrode, and
The active material is reduced and the second active material is oxidized.

Next, the first to fourth electrodes are brought into an open circuit state, and the second
- When an external load was applied between the third electrode, a battery was formed with an output voltage of about 1 V, with the third electrode as the positive electrode and the second electrode as the negative electrode.

As described above, using this device, photocharging - load (100KΩ)
After repeated discharges, the battery could be charged and discharged more than 1000 times at approximately 1V.

In this experiment, in addition to WO ₃ as the first active material,
It is generally reported as a positive electrode active material for secondary batteries. _{V2O5 , MoO3} , _Nb2O5 , _{TiO2 , Cr2O3 ,}
Transition metal oxides such as ZrO ₂ could be used. Furthermore, polymers having a biologen as a functional group which are generally reported as electrochromic materials, organic compounds such as polypyrrole, polythiophene, and polytynylene, iron cyano complexes such as Prussian blue and Berlin blue, and phthalocyanine metal complexes could be used.

As the electrolyte, propylene carbonate in which Li salts such as LiBF ₄ and LiClO ₄ were dissolved, organic electrolytes such as γ-butyrolactone, and aqueous solutions in which KBr, KCl, etc. were dissolved could be used.

As the second active material, a lower oxide (or reduced form) of the first active material mentioned above can be used, and other
Metal hydroxides such as _Ir (OH ₎

Example 2 In Example 1, instead of the a-Si semiconductor layer, CdS, CdSe, ZnS, ZnSe,
Similar experiments were performed using polycrystalline photovoltaic layers of -compounds such as CdTe. As a result, it was confirmed that it could be charged by light and functioned as a secondary battery.

Example 3 The first and second methods in Example 1 were performed without using a substrate.
A device was assembled using silicon single crystal substrates for the semiconductor layers 3 and 9, and the other materials described in Example 1, and similar experiments were conducted, and charging and discharging by light was confirmed. Compound semiconductors such as GaP, GaAs, InAs, and InP could also be used as single-crystal substrates.

Effects of the Invention By using the present invention, it is possible to achieve the functions of a so-called solar cell that uses light energy such as sunlight and fluorescent lamps, and also to electrically charge light energy in the form of chemical energy, thereby generating electrical energy when needed. It is possible to provide a completely new secondary photovoltaic cell that can be used as a device, and since semiconductor layers are provided on both sides of the device, it is possible to obtain twice as much power as a secondary photovoltaic cell that is provided with a semiconductor layer on one side.

[Brief explanation of the drawing]

The figure is a basic configuration diagram of a secondary photovoltaic battery according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... First electrode, 3... First semiconductor, 4... Second electrode, 5... First active material, 6...
Electrolyte, 7... Second active material, 8... Third electrode, 9
... second semiconductor layer, 10 ... fourth electrode, 11 ...
substrate.

Claims (1)

[Claims] 1. Electrodes are provided on both surfaces of the first semiconductor layer, an electrode active material layer is laminated on one electrode, and electrodes are provided on both surfaces of the second semiconductor layer, and a second semiconductor layer is provided on both surfaces of the second semiconductor layer. 1. A photo secondary battery comprising two electrode active material layers stacked one on top of the other, and the two electrode active materials facing each other with an electrolyte interposed therebetween. 2. The photo secondary battery according to claim 1, wherein the semiconductor layer is made of amorphous silicon.