JPS58126678A - Lithium battery - Google Patents

Abstract

PURPOSE:To obtain a laminated thin-film lithium battery, which can discharge at high voltage during discharge and can be charged with a voltage of around the electromotive force of the elementary battery during charge, by stacking thin-film lithium batteries and insulating members alternately, and providing a circuit which switches the connection of each elementary battery. CONSTITUTION:Elementary batteries each consisting of a positive material 1', a lithium-ion conducting electrolyte 2' and a negative material 3' are stacked, with insulating members 5' interposed between them, so as to make a main battery body 11. The main battery body 11 is provided with positive and negative terminals 12 and 13, which are connected to a connection-controlling circuit 14 by means of wirings 15 and 15'. Although electric power is supplied to a semiconductor device 18 usually from an external power source through a wiring 17, when the external power source is cut off, electric power is supplied to the semiconductor device 18 through a wiring 17' extending from the battery. After that, when the battery is charged through a wiring 16, the charge can be performed with such a small applied voltage as around 2V, which is the electromotive force of the elementary battery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to lithium batteries, and more particularly to lithium batteries in which the stacks are formed by thin films.

Lithium batteries are known to have a feature of high energy density, and are thin-film lithium batteries in which the electrolyte is manufactured using a sputtering deposition method, and the positive and negative electrodes are manufactured using a vapor deposition method or vapor phase reaction method, which is a method of thin film technology. is proposed. Since thin-film lithium batteries are manufactured using only this thin-film technology and can be manufactured directly on semiconductor devices, they have the advantage of being ultra-thin and being easily connected to the circuits of semiconductor devices.

The electromotive force of a unit cell of a lithium battery is 2 to 3V, and 10
In order to generate a high voltage higher than v, unit cells must be connected in series, but after that, when charging, a high voltage higher than the discharge voltage must be applied, which is an unfavorable condition, and the problem is that There is.

The present invention solves the above-mentioned conventional problems and provides a laminated thin film lithium battery that can be discharged at a high voltage when discharging, and can be charged at a voltage comparable to the electromotive force of a unit cell when charging.

In order to achieve the above object, the present invention achieves the above object by providing an IJ lithium battery in which thin film lithium batteries are laminated with an insulator interposed therebetween and is equipped with a circuit for switching the connection of the unit cells. This is what I did.

(Example 1) FIG. 1 is a model diagram of a battery (aJ) in which conventional unit cells are stacked without an insulator and a battery (b) in which unit cells are stacked via the insulator of the present invention. Figure 1 (a) and (b) both show a stack of three unit cells. In Figure 1, symbols 1 and 1' are positive electrode materials, 2 and 2' are lithium ion conductor electrolytes, and 3 and 3' 4 and 4' are current collectors, 5' is an insulator, and 6' is a wiring terminal for connection.

The discharge voltage of the conventional battery shown in FIG. 1(a) is three times the electromotive force of the unit cell, but the voltage applied during charging is also higher than three times the electromotive force of the unit cell.

On the other hand, the discharge voltage of the battery of the present invention is three times the electromotive force of the unit cell if all unit cells are connected in parallel. All batteries can be charged with voltage as low as electric power.

Note that in Figure 1, the thickness of the insulator and current collector is exaggerated to make the structure easier to understand, so you can see an increase in the thickness, but in an actual battery, these are the positive and negative electrodes. The thickness is less than that of the material, so there is no problem.

(Example 2) FIG. 2 shows an example in which the laminated thin film lithium battery of the present invention was fabricated on a semiconductor device chip operating at 12 V DC and used as a backup power source for a semiconductor device.

As shown in Fig. 1, unit cells are stacked with insulators in between, and a positive terminal 12 and a negative terminal 13 are provided on the main body 11 of the battery, and the battery is connected by wires 15 and 15'. It is connected to the control circuit 14. The semiconductor device 18 is normally powered from an external power source through the wiring 17, but if the external power is cut off, the wiring 17 from the battery is supplied.
The power will be supplied through '. Thereafter, the battery is charged through the wiring 16, and the voltage applied at this time can be as low as about 2V, which is the electromotive force of the unit cell.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a cross-sectional structure of the present invention, and FIG. 2 is a diagram showing an example in which the present invention is used as a backup power source for a semiconductor device. 1.1'... Positive electrode material, 2.2'... Electrolyte, 3゜3'... Negative electrode material, 4.4'... Current collector material, 5'...
・Insulator, 6'...Wiring terminal, 11...Battery failure part, 14...-3(1st (OL) A'(/')

Claims (1)

[Claims] 1. A lithium battery characterized in that a plurality of unit cells each made of a current collector, a negative electrode material, an electrolyte, a positive electrode material, and a current collector are stacked with an insulating material in between.