JPH01157059A - Cylinder type lithium battery - Google Patents

Abstract

PURPOSE:To realize a battery of a high capacity by forming a positive electrode by winding a sheet of positive electrode matter for carrying positive electrode agent around a current collecting rod spirally. CONSTITUTION:A sheet of positive electrode matter is wound around a current collecting rod spirally to form a positive electrode 3. The sheet of positive electrode matter is formed by applying positive electrode mixed agent 3a to be carried on current collecting net 3b. Current collecting effect is improved by existence of the current collecting net, and because in the sheet of positive electrode matter are formed proper intervals, electrolyte put in the intervals increases discharge effect of active material, so a battery of a high capacity with a weak discharge can be formed. The current collecting net shall be of metallic material such as stainless, for example, of which thickness shall preferably be about 100mum, and of which mesh size shall preferably be 30.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is a cylindrical battery that is used as a power source for small electronic devices related to electronics, and is particularly effective as a weak discharge battery such as a memory backup power source. Regarding lithium batteries.

(Conventional technology) Organic electrolyte batteries that use metallic lithium as the negative electrode have high energy density, excellent storage characteristics, and a wide operating temperature range. It is widely used as a weak discharge battery for power supplies, etc.

A cylindrical lithium battery, which is one of such organic electrolyte batteries, has a positive electrode mixture supported on a current-collecting network to form a positive electrode, and the positive electrode and negative electrode are formed into a sheet shape, and a separator is interposed between the positive electrode mixture and the negative electrode. It is known that the area of the electrode plate is increased by forming a spirally wound body (Utility Model Application No. 58-134).
863).

However, when spirally wound in this way, the volume occupied by the separator in the wound body increases, so
There was a problem that the volume of the positive cloudy negative electrode was reduced. In addition, in the process of spirally winding sheet-shaped positive and negative electrodes through a separator, loss between the electrodes is likely to occur due to the degree of binding between the separator and the positive and negative electrodes. Due to its structure, it is extremely difficult to wind it to increase its capacity.

Therefore, in Figure 0, which shows a cylindrical battery for weak discharge with a high capacity and a simple structure as shown in Figures 3 and 4, 11 is a cylindrical battery container formed from a nickel-plated iron plate. A lithium negative electrode plate 12 is provided in close contact with the inner wall. Reference numeral 13 denotes a positive electrode body, which is formed by pressure molding a positive electrode active material such as manganese dioxide, a conductive agent, and a binder into a cylindrical shape. Reference numeral 14 denotes a separator made of polypropylene nonwoven fabric or the like, which covers the outer periphery of the positive electrode body 13 . Further, this separator 14 is impregnated with an organic electrolyte. Reference numeral 15 denotes a stainless steel current collector, which is inserted and buried in the center of the positive electrode body 13, and its upper end is press-fitted into a fixed guide 16 made of aluminum.

This fixed guide 16 is tightly attached and fixed to the lower end of a caulking member 18 made of stainless steel that is fitted into an opening formed in the center of the sealing plate 17. The sealing plate 17 is made of a resin such as polypropylene, and is liquid-tightly caulked and fixed to the open end of the battery container 11, which serves as a negative electrode current collector. A positive electrode terminal 19 is fixed to the upper part of the caulking member 18 by spot welding. Note that 20 is a bottom insulating plate.

In this way, by encapsulating the outside of the positive electrode body 13 with the separator 14, the theoretical capacity of the positive and negative electrode active materials can be increased when filling the battery container 11. However, on the other hand, since the positive electrode body 13 is pressure-molded, it becomes difficult for the organic electrolyte with which the separator 14 is impregnated during discharge to penetrate into the inside of the positive electrode body 13.
The current collector rod 15 of the conventional size has problems such as insufficient surface area, poor current collection ability, and inability to obtain a sufficient amount of the actual capacity of the battery.

The present invention was made to solve the above problems, and
The purpose of the present invention is to provide a cylindrical lithium battery with high capacity for weak discharge.

[Structure of the Invention] (Means for Solving the Problems) The present inventors have repeatedly studied a structure in which an organic electrolyte with which a separator is impregnated easily permeates into the inside of a positive electrode body. As a result, the present inventors discovered that the permeability of electrolyte solution is improved by forming a positive electrode body in which a positive electrode mixture is supported on a current collecting network, and has thus arrived at the present invention.

That is, the cylindrical lithium battery of the present invention is a cylindrical lithium battery having a positive electrode formed around a current collector rod, and a lithium negative electrode disposed between the positive electrode and the inner surface of the battery container with a separator interposed therebetween. The positive electrode is characterized in that the positive electrode is formed by winding a sheet-like positive electrode body formed by supporting a positive electrode mixture on a current collecting net in a spiral shape around a current collecting rod.

In the present invention, the positive electrode is formed by spirally winding a sheet-like positive electrode body in which a positive electrode mixture is supported on a current collecting network around a current collector. In this positive electrode, the material of the current collecting network is not particularly limited as long as it allows the electrolyte impregnated in the separator to permeate into the inside of the positive electrode and exhibits a sufficient current collecting function, such as stainless steel. Metal materials such as On the other hand, the thickness of the current collecting net is 50 to 30
0 μ, more preferably 100 to 150 −1, particularly preferably 100, and the mesh constituting the net body is 10
mesh ~ lOO mesh, more preferably 20-40
The mesh size is particularly preferably 30 meshes.

Further, as the positive electrode mixture, any conventionally known mixture of positive electrode active material, conductive agent, and binder can be used as long as it can be supported on the current collecting network.

The thickness of this positive electrode mixture is 0.3 to 2.0 mm, more preferably 0.5 mm, since it is formed by winding the positive electrode.
~1. □am, particularly preferably 0.75IIIm.

Such a positive electrode is manufactured as follows.

First, a cathode mixture prepared by kneading a cathode active material, a conductive agent, and a binder in a predetermined ratio is supported on a current collecting net of a predetermined width, and then pressure-molded to form a sheet-like cathode body. . Next, this positive electrode body is connected and fixed to a current collector at one end of the current collecting net, and the positive electrode body is wound around the current collecting rod a predetermined number of times to form a positive electrode having a target diameter.

(Function) When a cylindrical lithium battery is configured as in the present invention, the current collecting effect is improved due to the presence of the current collecting network. Moreover,
Appropriate gaps are formed in the positive electrode made by winding a sheet-shaped positive electrode body, and the electrolyte that enters the gap increases the discharge efficiency of the active material, making it possible to create a cylindrical lithium battery with high capacity even with weak discharge. is obtained.

(Embodiments of the Invention) Examples Hereinafter, an AA-sized manganese dioxide/lithium battery which is an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

l is a cylindrical battery container made of nickel-plated iron.
A lithium negative electrode plate 2 is provided in close contact with the inner wall. 3 is a positive electrode, in which a sheet-like positive electrode body is formed by carrying a positive electrode mixture 3a on a stainless steel metal net 3b for current collection and then being pressure-molded, which is spirally wound around a stainless steel current collecting rod 4. It was formed.

Here, the positive electrode mixture is made by kneading a heat-treated manganese dioxide active material, a graphite powder conductive material, and a Teflon binder at a weight ratio of 5:2.5 at 90 nia, and its thickness is 0.75 mm. be. Also.

The metal mesh body 3b has a mesh size of 30 meshes,
It is a sheet with a width of 2.5co, a length of 10CI11, and a thickness of 100mm, and its end is connected to the current collector rod 4 by electric welding Φ
Fixed.

On the other hand, a separator 5 is interposed between the lithium negative electrode plate 2 and the positive electrode 3. This separator 5 is a non-woven fabric made of polypropylene, and is impregnated with an organic electrolyte consisting of propylene carbonate in which 1 mole of lithium perchlorate is dissolved.

Then, a fixed guide 6, a sealing plate 7, a caulking member 8, a positive electrode terminal 9, and a bottom insulating plate 10 configured in the same manner as the conventional cylindrical battery described above are arranged to form a cylindrical lithium battery as a final product. .

50 each using 100 AA cylindrical lithium batteries of the above configuration! A constant current continuous discharge test was performed at A and 1 mA, and the discharge capacity (mA
h) was investigated. The results are shown in Table 1 as average values.

Comparative Example For comparison, except for not using the above-mentioned current collecting net,
Two types of AA batteries were prepared using the same material for the positive electrode mixture, negative electrode, current collector rod, battery container, separator, and electrolyte. That is, an AA battery having the structure shown in FIGS. 3 and 4 described above, in which a positive electrode body is pressure-molded into a cylindrical shape, and a sheet-like positive electrode and a negative electrode are spirally wound with a separator interposed between them. This is an AA battery that uses a spiral electrode.

100 of each of these two types of batteries were prepared, and a discharge test was conducted under the same conditions as in the above example, and the discharge capacity i (m
Ah) was investigated. The results are respectively the former and Comparative Example 1.
The average values are also shown in Table 1, with the latter being taken as Comparative Example 2.

As is clear from Table 1, the battery of the present invention has significantly improved discharge capacity compared to conventional batteries.

In this example, a metal net was used as the current collecting net, but similar results were obtained even if lath metal was used.

[Effects of the Invention] The cylindrical lithium battery of the present invention can achieve high capacity as a weak discharge battery, and is a useful battery as a memory backup power source.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a cylindrical lithium battery showing an embodiment of the present invention, FIG. 2 is a cross-sectional view of the same, FIG. 3 is a vertical cross-sectional view of an example of a conventional cylindrical lithium battery, and FIG. The figure is also a cross-sectional view. 1...Battery container 2...Negative electrode lithium plate 3...
Positive electrode 3a... Positive electrode mixture 3b... Metal mesh 4.
・Collector rod Figure 1 Figure 2

Claims (1)

[Claims] In a cylindrical lithium battery having a positive electrode formed around a current collecting rod and a lithium negative electrode disposed around the positive electrode and the inner surface of the battery container with a separator interposed therebetween, the positive electrode is placed on a current collecting net. A cylindrical lithium battery characterized in that it is formed by spirally winding a sheet-like positive electrode body containing a positive electrode mixture around a current collector rod.