JP2506829B2 - Photovoltaic secondary battery - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an all-solid-state photovoltaic secondary battery including a solar cell and an all-solid-state secondary battery, and more particularly to a photovoltaic power generation device having a function as a driving power source for various power consumption devices. Regarding the next battery.

2. Description of the Related Art A number of power supply devices have been proposed that integrate a solar cell and a secondary battery, store the power generated by the solar cell in the secondary battery, and use it as a power source regardless of day and night (Masao Kaneko) Author Electronics P97-104, Showa 59).

Problems to be Solved by the Invention However, most of the conventional ones use a liquid electrolyte as an electrolyte that is a constituent element of the secondary battery portion. If a liquid electrolyte is used, it is difficult to integrate it with the solar cell due to liquid leakage, and the countermeasures made the structure complicated and large. In addition, in order to solve this problem, there is an example in which a non-solution type electrolyte is used. However, when using a non-solution type electrolyte, in order to obtain a large charging / discharging current, the electrolyte itself must first have a large ionic conductivity, and at the same time, as an active material of a secondary battery, It can be fully charged with the generated electromotive voltage without overcharging, has excellent reversibility during charge / discharge reactions, and has a low reaction resistance.In addition, the solar cells are exposed to direct sunlight etc. Since it receives a large amount, it must have excellent heat resistance. There has been no combination of an electrolyte and an active material that satisfies all of the above conditions.

Means for Solving the Problems In view of such problems, the present invention uses a chevrel compound as a battery active material that is a constituent element of a secondary battery portion and uses a solid electrolyte as an electrolyte.

Action As described above, when a solid electrolyte is used, there is no risk of liquid leakage, and therefore the structure is simple.
Easy to miniaturize. In addition, the rechargeability of the secondary battery using the chevrel compound as the active material is good at the charge / discharge reaction of the battery, and it can be fully charged at 0.6 (V) without overcharging. Silicon or the like may be used as a solar cell having an electromotive voltage (Japanese Patent Application No. 61-2).
6459). In addition, since the chevrel compound and the solid electrolyte are extremely thermally stable up to 1000 ° C. and 150 ° C., respectively, all the necessary conditions as an all-solid-state photo secondary battery pointed out in the above problems are satisfied.

Example (Example 1) FIG. 1 is a cross-sectional view showing the structure of a photovoltaic secondary battery that is an example of the present invention. On a transparent current collector _{2 in} which In ₂ O ₃ is vapor-deposited on a glass substrate 1 having a size of 20 × 20 mm and a thickness of 1 mm,
The p-type Si layer 3 is formed to a thickness of 0.1 μm by the CVD method, and further, the i-type Si layer 4 and the n-type Si layer 5 are each formed to a thickness of 0.1 μm by the CVD method. Next, a negative electrode current collector layer 6 containing carbon as a main component is formed on the n-type Si layer 5 by a screen printing method, and the pull screen is mainly composed of a copper chevrel compound Cu ₄ Mo ₆ S ₈ by the screen printing method. Negative electrode layer 7, RbCu ₄ I
_{Expressed as 1.5} Cl _3.5 . A solid electrolyte layer 8 and a positive electrode layer 9 mainly composed of a copper chevrel compound Cu ₂ Mo ₆ S _7.8 were sequentially formed.
The thickness of each of the above three layers was about 1 mm. The positive electrode layer 7 and the negative electrode layer 9 are prepared by premixing the powder of the copper chevrel compound and the solid electrolyte in a weight ratio of 8: 2, 3 ton /
After press forming with a pressure of cm ² , annealing is performed at 200 ° C. for 17 hours, and then this is crushed. Furthermore, this mixture 100
By weight, 10 parts by weight of a toluene solution was mixed to prepare a mixed agent slurry, which was screen-printed. The solid electrolyte layer 7 was prepared by mixing 100 parts by weight of the solid electrolyte powder with 10 parts by weight of a toluene solution to prepare a solid electrolyte slurry, which was screen-printed. Next, the same positive electrode current collector layer 10 as the negative electrode current collector layer 6 was formed on the positive electrode layer 9, and this was bonded to the transparent electrode 2. 11 and 12 are lead terminals,
Finally, the whole was sealed with a hermetically sealed package 13 made of an epoxy resin to prepare a photovoltaic secondary battery A.

The charging / discharging reaction of the photovoltaic secondary battery thus produced is as follows.

When the silicon layer having the pin junction is irradiated with light, the electrons excited from the valence band pass through the conduction band and are collected by the negative electrode current collecting electrode 6, and are placed on the negative electrode 7 and Cu ₄ Mo ₅ S ₈ + X (Cu ⁺ + e ^- ) ^- > induces the reaction represented by Cu _{4 + x} Mo ₅ S ₈ . In the positive electrode 9 tuned to this _{Cu 2 Mo 6 S 7.8 → Cu} 2-x Mo 6 S 7.8 + X (Cu + + e -) in the reaction takes place represented, electrons produced in this reaction is a positive electrode current collector It passes through the body 10 and flows into the p-type Si layer 3 from the transparent electrode 2 to form a flow of electrons. This is the current in the photocharge reaction. After a certain period of time, the secondary battery part becomes fully charged, and the battery active material of the copper chevrel compound has the composition of Mo ₆ S _{8 in} the positive electrode and Cu ₆ Mo ₆ S ₈ in the negative electrode, respectively. . In the fully charged state, the electromotive voltage generated in the solar cell is offset by the potential difference between Mo ₆ S _7.8 and Cu ₆ Mo ₆ S _8, and charging automatically stops.

Further, the discharge is performed by the lead terminals 11 and 12. Copper Chevrel compound, as the composition ratio of Cu is less electrically energy is high, when bonding the lead terminals 11 and 12, the positive electrode _{9 Mo 6 S 7.8 + X (} Cu + + e -) → Cu x Mo 6 S in _7.8 the negative electrode _{7, Cu 5 Mo 5 S 8} → Cu 5-x Mo 5 S 8 + X (Cu + + e -) reaction occurs naturally indicated by. This becomes a discharge reaction. In addition, between the electrode 2 and the electrode 6, silicon p-i is used.
Since the diode is formed by the -n junction, the current in the discharge direction does not flow and there is no fear of internal short circuit.

The following charge / discharge cycle measurement was performed on the photovoltaic secondary battery A.

First, a 1 KΩ resistor is connected to the lead terminals 11 and 12 as an external load. On the other hand, constant resistance discharge was performed by irradiating sunlight for 1 hour to perform photo-charging, and then leaving it in the dark for 1 hour. The voltage applied to the load resistance when this operation was repeated is shown in FIG. The vertical axis represents voltage and the horizontal axis represents elapsed time. FIG. 3 shows the cycle characteristics of the terminal voltage at the end of discharge that can be placed during the above operation. As can be seen from FIG. 3, the performance is hardly deteriorated even after 1000 photocharge / discharge cycles.

Further, in order to confirm the thermal stability of the battery A, the cycle characteristic test was conducted at 100 ° C. The results are shown in FIG. As can be seen from this, the battery according to this example exhibits excellent thermal characteristics.

(Example 2) A photovoltaic secondary battery having flexibility as a whole was prepared. The sectional structure is the same as that of FIG. 1 of the first embodiment. CVD of p-type Si layer 3 on transparent current collector _{2 in} which In ₂ O ₃ is vapor-deposited on polyimide film 1 having a size of 20 × 20 mm and a thickness of 0.1 mm.
Then, the i-type Si layer 4 and the n-type Si layer 5 were each formed to a thickness of 0.1 μm by the CVD method. Next, a negative electrode current collector layer 6 composed mainly of carbon is formed on the n-type Si layer 5 by a screen printing method, and the copper chevrel compound Cu ₄ M is formed by the screen printing method.
A negative electrode layer 7 mainly composed of o ₆ S ₈ , a solid electrolyte layer 8 represented by RbCu ₄ I _1.5 Cl _3.5 , and a positive electrode layer 9 mainly composed of a copper chevrel compound Cu ₂ Mo ₆ S _7.8 were sequentially formed. The thickness of each of the above three layers was about 1 mm. The positive electrode layer 7 and the negative electrode layer 9 are prepared by mixing the copper chevrel compound powder and the solid electrolyte powder in a weight ratio of 8: 2 in advance, press-molding at a pressure of 3 ton / cm ² , and then at 200 ° C. Anneal for 17 hours, then grind it. Furthermore, 100 parts by weight of this mixture and styrene-
1 part by weight of the ethylene-butadiene-styrene copolymer was mixed with 10 parts by weight of a toluene solution to prepare a mixed agent slurry, which was screen-printed. Further, the solid electrolyte layer 7 is prepared by mixing 100 parts by weight of the solid electrolyte powder and 1 part by weight of the styrene-ethylene-butadiene-styrene copolymer with 10 parts by weight of a toluene solution to prepare a solid electrolyte slurry.
This was screen printed. Next, the same positive electrode current collector layer 10 as the negative electrode current collector layer 6 was formed on the positive electrode layer 9, and this was bonded to the transparent electrode 2. 11 and 12 are lead terminals, and finally, the whole is sealed with a hermetically sealed package 13 made of epoxy resin to prepare a photovoltaic secondary battery B.

FIG. 5 and FIG. 6 show the results of the same charge / discharge cycle characteristic test of Example 1 for this photovoltaic secondary battery B. It can be seen that the photovoltaic secondary battery B of Example 2 also has substantially the same performance as the photovoltaic secondary battery A of Example 1.

Example 3 One of the features of the photovoltaic secondary battery according to the present invention is that the manufacturing method is easy. In other words, it is completed by electrically connecting and integrating the all-solid-state secondary battery portion from the back surface to the solar cell created in advance. According to this manufacturing method, the solid secondary battery portion may be attached to the rear surface of any solar cell regardless of the electromotive voltage of the solar cell used. Hereinafter, this example will be described.

The P-N junction Si solar cell shown in FIG. 7 was prepared in advance. 21 is a resin printed circuit board with an external dimension of 27.5 x 29.5 mm,
22 is an Al electrode, 23 is a P-N junction solar cell element, 24 is a transparent electrode, 25 is a sealed package, and the operating voltage is 1.5 volts.

Next, on the back surface of the printed circuit board 30, a solid secondary battery portion 39
A solar cell portion 31 was formed on the other surface. The solid state secondary battery element has three cells connected in series, which is shown in FIG. 32 is a positive electrode terminal, 33 is a positive electrode layer, 34 is a solid electrolyte layer, 35 is a negative electrode layer, 36 is a connection lead, 37 is a negative electrode terminal, 38 is a resin sealed package, 33 to 35 materials, thickness, and The manufacturing method is the same as that of the battery of Example 1.

With respect to the battery C of this example created in this way,
9 and 10 show the results of the same charge / discharge cycle characteristic test of Example 1. It can be seen that the all-solid-state photovoltaic secondary battery of Example 3 also has substantially the same performance as the photovoltaic secondary battery of Example 1.

EFFECTS OF THE INVENTION As described above, according to the present invention, a small and thin all-solid-state photovoltaic secondary battery having excellent thermal stability can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an all-solid-state photovoltaic secondary battery according to an embodiment of the present invention, FIGS. 2, 3, and 4 are characteristic diagrams of the photovoltaic secondary battery, FIG. 5, and FIG. FIG. 6 is a characteristic diagram of a photovoltaic secondary battery according to another embodiment of the present invention, FIG. 7 is a configuration diagram of a solar cell portion of a photovoltaic secondary battery according to another embodiment of the present invention, and FIG. FIG. 7 is an overall configuration diagram of a photovoltaic secondary battery having the solar cell portion shown in FIG. 7 as a constituent element, and FIGS. 9 and 10 are characteristic diagrams of the photovoltaic secondary battery shown in FIG. 1 ... Support substrate, 2 ... Transparent electrode, 3 ... P-type Si, 4 ...
... i-type Si, 5 ... n-type Si, 6 ... current collecting electrode, 7 ... negative electrode, 8 ... solid electrolyte, 9 ... positive electrode, 10 ... current collecting electrode,
11 …… Positive lead terminal, 12 …… Negative lead terminal, 13 ……
Sealed package.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Sotobe, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Shigeo Kondo, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. In-house (56) References JP 61-88468 (JP, A) JP 59-63673 (JP, A)

Claims (3)

(57) [Claims] 1. An all-solid secondary battery formed by sequentially laminating a positive electrode molded body layer mainly containing a chevrel compound, a solid electrolyte molded body layer, and a negative electrode molded body layer mainly containing a chevrel compound. A photovoltaic secondary battery, characterized in that a solar cell formed by interposing a photoelectric conversion film between a pair of electrodes is electrically connected and integrally configured. 2. The positive electrode molded body layer and the negative electrode molded body layer are a mixture of at least respective electrode main materials and a plastic binder, and the solid electrolyte molded body layer comprises a solid electrolyte, a plastic binder and, if necessary, a core material. A solid electrolyte molded body consisting of the above, and an all-solid secondary battery formed by these is electrically connected to a photoelectric conversion element on a flexible transparent resin substrate. The photovoltaic secondary battery according to the item. 3. A chevrel compound is a copper chevrel compound or a silver chevrel compound, and correspondingly, the solid electrolyte is a copper ion conductive solid electrolyte or a silver ion conductive solid electrolyte, respectively. The photovoltaic secondary battery according to claim 1 or 2.