JPS59230257A - Positive electrode for nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To increase electrolyte holding capability and mechanical strength of a positive electrode by mixing a specified amount of graphite and carbon black to manganese dioxide with a binder and kneading them and supporting them in a sheet form on a porous substrate. CONSTITUTION:7-12pts.wt. graphite and 0.5-15pts.wt. carbon black are mixed to 100pts.wt. manganese dioxide, and water and a binder are added to them to make slurry. The slurry is spreaded on a porous conductive substrate such as punched metal, and dried. This coated metal is pressed to make a sheet, then the sheet is cut to a specified dimension to form a positive electrode for a nonaqueous electrolyte battery. This positive electrode is suitable for a winding electrode. By using this electrode, a nonaqueous electrolyte battery having low internal resistance and good high rate discharge performance is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positive electrode for a non-aqueous electrolyte, particularly to one constituting a spiral electrode body.

Generally, a non-aqueous electrolyte battery includes a negative electrode made of a light metal such as lithium, sodium, or aluminum, a separator impregnated with a non-aqueous electrolyte, and a positive electrode. By the way, this type of non-aqueous electrolyte battery generally has a large internal resistance, and therefore it is necessary to ensure that the opposing area between the positive electrode and the negative electrode is as large as possible. Therefore, in a cylindrical non-aqueous electrolyte battery, the positive electrode and the negative electrode are each formed into sheet shapes. Then, the sheet-like positive electrode body is spirally wound together with a separator and a negative electrode to form an electrode body.

The present invention relates to a sheet-like positive electrode body for constructing such a spiral electrode body, particularly one using manganese dioxide as a positive electrode active material.

By the way, when manganese dioxide is used as a positive electrode active material, it cannot be used as a positive electrode for this type of non-aqueous electrolyte battery unless a suitable conductive material is mixed in to increase the conductivity. Conventionally, therefore, graphite, carbon black, or the like has been used as the conductive material. Specifically, a mixture of manganese dioxide and graphite or manganese dioxide and carbon black was kneaded with a binder, and this was supported in the form of a sheet on a porous conductive substrate such as punched metal. . However, in order to obtain the necessary conductivity, it is necessary to mix a large amount of graphite, which causes the problem of lowering the content of manganese dioxide, which is the positive electrode active material, and lowering the discharge capacity. was. Also, 1[
When graphite is used as a material, the retention of non-aqueous electrolyte is poor, and as a result, ions cannot move smoothly inside the cathode body, resulting in a significant decrease in the utilization rate of the cathode active material during heavy load discharge. There were also problems like this.

On the other hand, when carbon black is used as a conductive material, it has better conductivity than the above-mentioned graphite, but has poor moldability and shape retention when forming a sheet-like electrode body. For example, it was not suitable for constructing a spiral electrode body.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to improve the moldability of manganese dioxide without reducing the effective content of manganese dioxide, which is a positive electrode active material. It is possible to secure shape retention and improve the mechanical strength characteristics of the positive electrode body, while also ensuring good electrolyte retention, which reduces internal resistance and performs heavy load discharge performance. An object of the present invention is to provide a positive electrode for a non-aqueous electrolyte battery which has a Q- quality so as to improve the quality of the battery.

In order to achieve the above object, the present invention has developed a porous conductive substrate by kneading 1001 parts of manganese dioxide, 7 to 12 parts of graphite, and 0.5 to 1.5 parts by weight of carbon black with a binder. It is characterized by being supported in the form of a sheet.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIGS. 1 and 2 show an embodiment of a positive electrode for a non-aqueous electrolyte battery according to the present invention.

First, as shown in FIG. 1, a positive electrode 12 is held on a porous conductive substrate 14, such as punched metal, to form a sheet positive electrode body 10. The positive electrode 12 is made by adding 7 to 12 parts by weight of graphite and 0.5 to 1.5 parts by weight of carbon black to 1001 ffi parts of manganese dioxide.
After mixing, water and a binder are added to form a slurry.

Next, this slurry-like material is applied, dried, and pressed onto a porous conductive substrate 14 such as bunched metal to form a sheet.

Then, it is cut to a predetermined size.

Next, the sheet-like positive electrode body 10 constructed as described above is wound together with the separator 16° and the negative electrode 18 to form a spiral electrode body, as shown in FIG. Then, this spiral electrode body is immersed in a non-aqueous electrolyte in a battery can, thereby forming a non-aqueous electrolyte battery.

Here, if the amount of carbon black added is less than 0.5 parts by weight, the electrolyte retention property of the positive electrode will decrease, thereby increasing the internal resistance and deteriorating the heavy load discharge performance. On the other hand, if the amount of carbon black added exceeds 1.5 parts by weight, moldability and shape retention deteriorate, making it impossible to obtain sufficient mechanical strength characteristics to form a spiral electrode body. . Furthermore, if the amount of graphite added is less than 7 parts by weight, sufficient conductivity cannot be imparted, resulting in a decrease in battery performance such as an increase in internal resistance. On the other hand, when the amount of graphite added exceeds 12 parts by weight, the content of manganese dioxide, which is the positive electrode active material, decreases, resulting in a decrease in the effective power generation capacity4-, and the characteristics as a non-aqueous electrolyte battery deteriorate. It will be lost. However, when manganese dioxide, graphite, and carbon black are used in the above-mentioned ratios, both moldability and shape retention are good, and the mechanical strength properties when formed into a sheet or spiral shape are also good. It was confirmed that the retention of electrolyte in the positive electrode was improved, the internal resistance was reduced, and heavy load discharge performance etc. were significantly improved.

Specific examples will be shown below.

100 parts by weight of manganese dioxide, 9 parts by weight of graphite,
Mix 1 part by weight of carbon black. A wetting agent is added to this mixture and the mixture is kneaded, applied to a 5LIS (stainless steel) substrate, and dried to form a sheet. The wetting agent used is 6 parts by weight of Teflon dispersion added to 55 parts by weight of water. Further, metallic lithium is used as the negative electrode, and polypropylene nonwoven fabric is used as the separator, and is wound together with the sheet-like positive electrode body to form a spiral electrode body. Then, the battery was inserted into a negative electrode can, terminals were attached, and non-aqueous electrolyte was injected, followed by sealing to form a non-aqueous electrolyte battery.

The non-aqueous electrolyte battery constructed as described above has significantly fewer defective products than conventional ones of the same type, and also has low internal resistance and good performance. We were able to obtain heavy load discharge performance.

As described above, the positive electrode for non-aqueous electrolyte batteries according to the present invention has improved electrolyte retention and mechanical bullet hole characteristics.
It is now possible to simultaneously satisfy requirements that were previously contradictory to each other, making it possible to construct a battery with stable quality, and to construct a non-aqueous electrolyte battery with low internal resistance and excellent heavy-load discharge performance. be able to.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an example of a positive electrode for a non-aqueous electrolyte battery according to the present invention. FIG. 2 is a cross-sectional view showing a state in which a spiral electrode body is formed using the above-mentioned positive electrode. 10... Sheet-like positive electrode body 12...
... Positive electrode 14 ... Porous conductive substrate 16 ...
...Separator 18...Negative electrode

Claims (1)

[Claims] (1) Manganese dioxide 100 heavy duty part, graphite 7~
1. A positive electrode for a non-aqueous electrolyte battery, characterized in that 12 parts by weight of carbon black and 0.5 to 15 parts by weight of carbon black are kneaded together with a binder and supported in the form of a sheet on a porous conductive substrate.