JPH01241767A - Solid electrolyte secondary cell - Google Patents

Abstract

PURPOSE:To make it possible to maintain a stable cell property even though the charge and the discharge are repeated so many time by laminating a positive electrode which consists of a metallic membrane a positive electrode active substance is attached, an organic solid electrolyte membrane, and a negative electrode which consists of a metallic membrane a negative electrode active substance is attached, in this order. CONSTITUTION:As a negative electrode, a metallic membrane 1 to which carbon particles 2 to allow the output and the input of lithium in the charge and discharge are attached is used, and as a positive electrode, a metallic membrane 4 to which positive electrode active substance particles 5 of a metal oxide, a metal sulfide, or the like are attached is used. A lithium ion source necessary for the charge and discharge is included in the active substance particles of either the positive or the negative electrode beforehand. The basic unit of the cell is composed by placing a lithium ion conductive organic solid electrolyte between the positive and the negative electrodes, and such composition units are formed in one layer or plural layers to make a secondary cell. Consequently, a solid electrolyte secondary cell of a free form and an excellent charge and discharge property can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid electrolyte secondary battery that is small, lightweight, has a high capacity, and does not leak.

[Prior Art] Conventionally, various lightweight and high-capacity secondary batteries have been proposed in which a lithium metal foil or lithium alloy foil is used as a negative electrode in combination with various positive electrode active materials. In addition, as organic solid electrolytes, poly(ethylene oxide), copolymers of ethylene oxide and propylene oxide,
Alternatively, crosslinked products having these structures have been proposed in which lithium ion conductivity is imparted. Furthermore, in recent years, carbon particles with a specific structure have been proposed as a negative electrode active material in place of lithium. However, this cell combines liquid propylene carbonate and a lithium salt electrolyte.

[Problems to be solved by the invention] Secondary batteries using organic solid electrolytes are lightweight, high-capacity, and leak-free secondary batteries. Since lithium is used, there is a problem in that the negative electrode and the solid electrolyte react with each other, and the characteristics of the battery deteriorate due to repeated charging and discharging.

The present invention provides a battery that exhibits excellent performance without using highly reactive lithium as a negative electrode active material in manufacturing a secondary battery that is lightweight, high capacity, and free from leakage. With the goal.

[Means for Solving the Problems] In order to achieve the above object, the solid electrolyte secondary battery of the present invention has a positive electrode consisting of a metal thin film to which a positive electrode active material is adhered, an organic solid electrolyte membrane, and a negative electrode active material. The present invention is characterized by comprising at least one laminate in which negative electrodes made of thin metal films are sequentially laminated.

[Function] In the present invention, carbon particles that allow lithium ions to enter and exit during charging and discharging are bonded to a metal thin film for the negative electrode, and metal oxides, metal sulfides, etc. are used for the positive electrode. Positive electrode active material particles bonded to a metal thin film are used, and the lithium ion source necessary for charging and discharging is contained in advance in the active material particles of either electrode. A structure in which a lithium ion conductive organic solid electrolyte membrane is interposed between these positive and negative electrodes is used as the basic unit of the battery, and one or more layers of this structural unit are formed to form a secondary battery.

With this configuration of the present invention, it is possible to realize a solid electrolyte secondary battery that has a free shape and has excellent charge and discharge characteristics.

[Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing the basic configuration of the present invention. In the figure, 1 is a metal thin film of the negative electrode current collector, for example, the thickness is 1
It consists of a 0 μm copper thin film. 2 is a negative electrode active material particle layer adhered to the metal thin film 1, and has a particle size of, for example, 0.5 to 20 μm.
It is made of a mixture of carbon, fluororesin, and fluororubber, and has a thickness of about 100 μm. The negative electrode active material particle layer 2 may be directly adhered to the metal thin film 1, and may be made of, for example, a carboxyl modified polyolefinic polystyrene block rubber containing about 50 wt of carbon particles with a particle size of 0.01 to 1.0 μm. It is more preferable to adhere to the metal thin film 1 through an adhesive layer such as the above, in order to increase the contact area and strengthen the adhesive force. Reference numeral 3 denotes a lithium ion conductive organic solid electrolyte membrane, for example, a membrane made of a crosslinked copolymer of ethylene oxide and propylene oxide imparted with lithium ion conductivity. Reference numeral 4 denotes a metal thin film of a positive electrode current collector, which is made of aluminum with a thickness of 15 μm, for example. 5 is a positive electrode active material layer adhered to the metal thin film 4, which is made of, for example, a mixture of positive electrode active material particles made of a lithium-containing cobalt oxide fired body, a fluorine-based resin, and a fluororubber;
The thickness is about 100μ. The positive electrode active material layer 5 may be directly adhered to the metal thin film 4, and the negative electrode active material particle layer 2 may be bonded directly to the metal thin film 4.
Similarly, it is more preferable to bond via an adhesive layer containing carbon particles.

The structure shown in FIG. 1 is the basic structure of the secondary battery of the present invention, and can constitute a battery by itself, and can also be repeated to construct a secondary battery.

It is necessary that lithium can be inserted into the carbon particles as the negative electrode active material particles. Its particle size is preferably 0.5
~20 μm. The content of carbon particles is preferably 85
~99. Polyacrylonitrile resin can also be used as the adhesive resin for the negative electrode active material particle layer.

The thickness of the solid electrolyte layer is appropriately selected depending on the battery capacity.

As the positive electrode active material, fired particles of lithium-containing vanadium pentate, lithium-containing manganese dioxide, or the like, or metal sulfide particles can be used, and the particle size is preferably 5 to 100 μm. The amount of active material is preferably 85
~999g.

Nickel having a thickness of about 25 μm can also be used as the metal thin film of the positive electrode current collector.

FIG. 2 and FIG. 3 illustrate a button type battery having one repeating structural unit. In FIGS. 2 and 3, reference numeral 6 denotes a battery exterior can that also serves as a negative electrode terminal, and is fixed with an insulating resin 7. In FIG. 2, 8 is a positive electrode terminal 9 sealed with insulating glass. FIG. 2 shows a hermetically sealed button battery. FIG. 3 shows a button-type battery in which a battery outer can 1O, which also serves as a positive electrode terminal, is sealed with resin 7 and the can is sealed.

In the battery invented by Kiyoshi, both the positive and negative electrodes are composed of a metal thin film and an active material layer adhered to this, so it has excellent processability and is highly flexible, so it can be easily bonded to the solid electrolyte layer. Good sex.

FIG. 4 shows an embodiment of a stacked battery according to the present invention. In this embodiment, a positive electrode current collector metal 4 and a negative electrode current collector metal 1 are provided at both the upper and lower ends, respectively, and a negative electrode current collector metal 1 and a positive electrode current collector metal 4 are further provided in the middle. A negative electrode active material layer 2 and a positive electrode active material layer 5 are adhered to both sides of the intermediate negative electrode current collector metal 1 and the positive electrode current collector metal 4, respectively, and as a whole, three repeating units shown in FIG. It is a built-in structure.

FIG. 5 shows another embodiment of the laminated battery. This example is a stacked battery having three repeating structural units as shown in FIG. Although not shown, the positive electrode and the negative electrode are connected to each other. 11 is an insulating film.

As mentioned above, in the wooden invention, since the electrode is flexible, even when multiple layers are laminated, the adhesion between the active material layer and the solid electrolyte layer in each layer is not impaired.

FIG. 6 shows a spiral secondary battery in which the above-described repeating unit is wound with an insulating film 11 interposed therebetween. It consists of a cylindrical battery can 12 which also serves as a negative electrode terminal, and a seal i13 with a positive electrode terminal 9 sealed with insulating glass 8.

FIG. 7 shows a spiral secondary battery in which a repeating structural unit is wound with an insulating film 11 in between, and a resin gasket 15 and a battery sealing cap i16 are fitted into a battery can 14 which also serves as a negative electrode terminal. It is worn. 17 is a positive terminal.

As mentioned above, the battery of the present invention is highly flexible, so when forming a spiral battery as shown in Figures 6 and 7, it can be wound at a higher speed than conventional batteries. .

FIG. 8 shows the discharge characteristics of the secondary battery according to the present invention. The battery used was a button type battery shown in FIG. 2, in which the positive and negative current collector metal thin films and the active material layer were each bonded via an adhesive layer containing carbon particles. As shown in the figure, the solid state secondary battery of the present invention maintains stable characteristics even when the discharge time exceeds 2 hours. This is because lithium is not used as the negative electrode active material, and furthermore, the active material does not peel off from the current collector metal thin film.

[Effects of the Invention] As explained above, the solid electrolyte secondary battery of the present invention has the following features:
Since the electrode structure is flexible, the adhesion between the active material layer and the solid electrolyte is good and overvoltage is small. Furthermore, the overall battery structure has excellent flexibility, allowing a large degree of freedom in battery shape, especially for spiral-type secondary batteries constructed by winding a laminate consisting of positive and negative electrode layers and an electrolyte layer. suitable. Furthermore, in the present invention, since lithium is not used in the negative electrode and the active material does not peel off from the current collector metal thin film, stable battery characteristics can be maintained even after repeated charging and discharging many times. Further, the secondary battery of the present invention is particularly suitable for thin batteries such as sheet-shaped and paper-shaped batteries.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the basic structure of the present invention, FIGS. 2 and 3 are cross-sectional views of an embodiment of a button-type battery according to the present invention, and FIGS. 4 and 5 are respectively cross-sectional views of a laminated battery according to the present invention. FIGS. 6 and 7 are perspective views of embodiments of the spiral-shaped battery according to the present invention, and FIG. 8 is a characteristic diagram showing the discharge characteristics of the solid state secondary battery according to the present invention. DESCRIPTION OF SYMBOLS 1... Metal thin film of negative electrode current collector, 2... Negative electrode active material particle layer, 3... Organic solid electrolyte membrane, 4... Metal thin film of positive electrode current collector, 5... Positive electrode active material Layer, 6... Battery outer can, 7... Insulating resin, 8... Insulating glass, 9... Positive electrode terminal for hermetic seal, lO... Battery outer can and positive electrode terminal, 11. ... Insulating film, 12... Cylindrical battery can for hermetic sealing, 13... Sealing lid for hermetic sealing, 14... Cylindrical battery can for fitting, 15... Resin gasket, 16... Battery sealing lid for fitting, 17...Positive electrode terminal. Figure 1 Figure 4 Figure 5 Figure 32 D Figure 6

Claims (1)

[Claims] 1) At least one laminate including a positive electrode made of a metal thin film to which a positive electrode active material is adhered, an organic solid electrolyte membrane, and a negative electrode made of a metal thin film to which a negative electrode active material is laminated in sequence. Characteristics of solid electrolyte secondary batteries.