JP2002203589A - Cylindrical secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical secondary battery having good performance by reducing a short circuit depending on softening and swelling of an active material in a winding central part accompanying the progress of a recharging/ discharging cycle. SOLUTION: In the cylindrical secondary battery having a spiral electrode plate group that a positive electrode which makes a positive-electrode active material hold on a positive-electrode base substance, and a negative electrode which makes a negative-electrode active material hold on a negative-electrode base substance are wound through a separator, the cylindrical secondary battery is constituted so that at least one of the two of the above positive/negative electrode may be formed with an active-material non-holding part 12 in the start end of the winding on the face of the base substance. Then, the cylindrical secondary battery having good performance is provided by reducing the short circuit depending on softening and swelling of the active material in the winding central part accompanying the progress of the recharging discharging cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cylindrical secondary battery.

[0002]

2. Description of the Related Art Principal secondary batteries currently in practical use include lead storage batteries, nickel cadmium storage batteries, nickel metal hydride batteries, silver zinc oxide batteries, and lithium ion batteries.

A lead-acid battery uses lead dioxide as a positive electrode active material, lead as a negative electrode active material, and dilute sulfuric acid as an electrolyte, and has an operating voltage of about 2V. This battery has a balance in terms of quality, reliability, and price, and is widely used for automobiles, electric vehicles, uninterruptible power supplies, and the like. In recent years, the technology of miniaturization has been advanced, and its usefulness has been increased for various cordless devices.

A nickel cadmium storage battery uses nickel oxyhydroxide as a positive electrode active material, cadmium as a negative electrode active material, and an aqueous solution of potassium hydroxide as an electrolyte.
V operating voltage. This battery is widely used mainly for consumer equipment because it has features such as low internal resistance, capable of discharging large current, long cycle life, strong resistance to overcharging and overdischarging, and wide operating temperature range. .

A nickel-metal hydride battery uses nickel oxyhydroxide as a positive electrode active material, a hydrogen storage alloy as a negative electrode active material, and an aqueous solution of potassium hydroxide as an electrolytic solution. The operating voltage is about 1.2V. It has a high energy density and has been put to practical use mainly in various consumer devices.

[0006] A silver zinc oxide battery uses silver oxide as a positive electrode active material,
It uses zinc as the negative electrode active material and potassium hydroxide as the electrolyte. While having high output and high energy density, large ones are mainly used for space and deep sea because of their high cost, while small ones are widely used for watches and calculators.

[0007] Lithium ion batteries use Li as a positive electrode active material.
Li metal composite oxides such as CoO2, LiNiO2 and LiMn2 O4, a carbonaceous material for the negative electrode, and an organic solution for the electrolyte, and have an operating voltage on the order of 3V. Due to advantages such as high operating voltage, high energy density, and no memory effect, applications for consumer use are rapidly expanding.

[0008] The above-mentioned practical secondary batteries are provided in the form of a prism, a cylinder, a button, a sheet or the like depending on the application.

As is well known, a cylindrical secondary battery includes an electrode plate group in which a positive electrode and a negative electrode are spirally wound with a separator interposed therebetween. Is increasing.

There are various types of bases (also referred to as grids, substrates, and current collectors) of a secondary battery having a spiral electrode group.
One of them is a so-called grid having a vertical bar and a horizontal bar, and a lead-acid or lead alloy battery is used in a cylindrical lead-acid battery or the like. FIG. 1 is a schematic view thereof, wherein 1 is a vertical bar, 2 is a horizontal bar, 3 is an electrode plate ear formed on the upper part of a picture frame, and 4 is a square. The one shown in FIG. 2 is one in which conductive leads 6 are attached to a nonporous foil body 5 having conductivity such as aluminum or copper metal or resin, and is used in a lithium ion battery or the like. FIG. 3 is a diagram showing a state in which the grid shown in FIG. 1 is filled with the active material 7, and FIG. 4 is a diagram showing a state in which the active material is applied to the base shown in FIG.

FIG. 5 is a schematic view showing a winding method for forming a spiral electrode group using such an electrode plate. A half-shaft shaft 10 is used to form a positive electrode plate 8 and a negative electrode plate 9. Are wound through the separator 11. FIG. 6 is a diagram showing the spirally wound electrode group formed as described above.

[0012]

However, since a hollow portion corresponding to the shaft body 10 is present at the center of such a spirally wound electrode plate group, a counterpart is provided inside the winding of each of the positive and negative electrode plates. There is a problem in that no compressive force is applied to a portion where no pole is present, and the active material is softened or expanded with the progress of the charging / discharging cycle, possibly leading to a short circuit. In particular, this phenomenon is remarkable in a lead storage battery, but other cylindrical secondary batteries have similar problems.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and reduces a short circuit due to softening or swelling of an active material at the center of a winding due to the progress of a charging / discharging cycle. An object of the present invention is to provide a cylindrical secondary battery having good performance.

[0014]

Means for Solving the Problems A first invention for solving the above-mentioned problems is to provide a positive electrode having a positive electrode active material held on a positive electrode substrate and a negative electrode having a negative electrode active material held on a negative electrode substrate. In a cylindrical secondary battery including a spirally wound electrode plate group wound via a separator, at least one of the positive and negative electrodes has an active material non-holding portion formed at a winding start end of a substrate surface. It is a cylindrical secondary battery characterized by the following.

A second aspect of the present invention is the cylindrical secondary battery according to the first aspect of the present invention, wherein the active material non-holding portion is about half a turn.

A third invention is a cylindrical secondary battery according to the first or second invention, wherein the active material non-holding portion is only on the inner side of the winding.

A fourth aspect of the present invention is the cylindrical secondary battery according to the first aspect, wherein the active material non-holding portion is not wound.

A fifth invention is the cylindrical secondary battery according to the first, second, third or fourth invention, wherein the base is a lattice.

A sixth aspect of the present invention is the cylindrical secondary battery according to the fourth aspect, wherein no grid is formed in the active material non-holding portion.

A seventh invention is the cylindrical secondary battery according to the first, second, third or fourth invention, wherein the base is a non-porous foil.

An eighth invention is characterized in that the positive electrode active material is mainly composed of lead dioxide, the negative electrode active material is mainly composed of lead, and the current collector is lead or a lead alloy. 4,
It is a cylindrical secondary battery according to the invention of 5, 6, or 7.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A cylindrical secondary battery according to a first aspect of the present invention includes a positive electrode having a positive electrode active material held on a positive electrode substrate and a negative electrode having a negative electrode active material held on a negative electrode substrate, with a separator interposed therebetween. In a cylindrical secondary battery including a spirally wound electrode plate group, at least one of the positive and negative electrodes is characterized in that an active material non-holding portion is formed at a winding start end of a substrate surface. It is more preferable that both the positive and negative electrodes have an active material non-holding portion formed at the winding start end of the substrate surface. FIG. 7 shows the active material 7 held on the lattice shown in FIG. 1, and FIG.
An active material is held on the substrate shown in FIG. In each case, the active material non-holding portion 12 is formed at the winding start end of the substrate surface.

The active material non-holding portion at the winding start end of the substrate surface is preferably formed in a band shape as shown in FIGS. 7 and 8, but the active material non-holding portion is partially formed as shown in FIG. The non-holding portion 12 may be used. This is because, compared to at least the case where the active material is held up to the winding start end of the substrate surface as shown in FIGS. Is reduced. The width of the active material non-holding portion at the winding start end is a design item that can be appropriately selected according to the specifications of the cylindrical secondary battery and the electrode specifications. 7 and 8,
Active material non-holding portions 13 are also formed on the upper and lower portions of the base surface, but this is not a compulsory requirement of the present invention and is a design item that can be appropriately selected. Furthermore, in these figures, the active material is held up to the winding end portion of the base surface, but the active material non-holding portion 14 may be formed as shown in FIG.

The second invention is characterized in that the active material non-holding portion is about half a turn. About half a turn
It is not a strict mathematical definition, but means portions 15 and 16 where the other electrodes are not inscribed, as shown by the black portions in FIG. According to this, the softening and swelling of the active material in a portion of the base surface where the other electrode is not inscribed at the winding start end is reduced, and a short circuit is reduced. Substances can be omitted.

The third invention is characterized in that the active material non-holding portion is only on the inner side of the winding of the base. As shown in FIG. 11, even if the hollow portion 17 exists at the center of the spiral electrode group, depending on the configuration such as the rigidity of the substrate and the electrodes, the winding outside of the portions 15 and 16 where the other electrodes are not inscribed is the other side. The electrode may be held in contact with moderate pressure. In that case, by setting the active material non-holding portion only on the inner side of the winding, the amount of the active material held on the base increases, albeit slightly.
This contributes to an increase in battery capacity.

A fourth aspect of the invention is characterized in that the active material non-holding portion is not wound. According to this, as shown in FIG. 13, in the cylindrical secondary battery including the spirally wound electrode plate group including the non-winding winding start end 18, the winding center portion accompanying the progress of the charging / discharging cycle. The short circuit due to softening or swelling of the active material can be reduced.

The fifth invention is characterized in that the base is a lattice. The grid includes not only a cast grid and an expanded grid used in a lead storage battery, but also a metal plate or a foil having a rectangular hole or a circular hole. ADVANTAGE OF THE INVENTION According to this invention, a favorable lead storage battery and other lightweight cylindrical secondary batteries can be provided.

The sixth invention is characterized in that, as shown in FIG. 9, no grid is formed in the active material non-holding portion at the winding start end. In the case of an electrode in which the active material is mainly held in the grid cells, such as a lead storage battery, in the active material filling step, the portion where the cells corresponding to the winding start end are not formed is filled with the active material. Therefore, the workability is improved.

The seventh invention is characterized in that the substrate is a non-porous foil as shown in FIG. As the non-porous foil, a conductive metal or resin can be used. Accordingly, a cylindrical secondary battery having a spirally-shaped electrode group which is thinner and can reduce a short circuit due to softening or swelling of the active material at the center of the winding as the charge / discharge cycle progresses is provided. .

An eighth invention is characterized in that the positive electrode active material is mainly composed of lead dioxide, the negative electrode active material is mainly composed of lead, and the current collector is lead or a lead alloy. Thereby, a short circuit due to softening or swelling of the active material at the center of the winding due to the progress of the charging / discharging cycle can be reduced, and a cylindrical lead-acid battery having good performance can be provided.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, as a conventional example, specific gravity is 11.3 g / cc.
Lattice was manufactured by using a non-antimony lead alloy foil. Grid dimensions are 0.6mm thick x 80m wide
The grid was mx 500 mm in length, 1.5 mm in width, 1.5 mm in width, 1.5 mm in width, and 5 mm (length) × 7 mm (width). Note that pure lead may be used instead of the non-antimony lead alloy.

Using the lattice as a positive and negative substrate, a cylindrical sealed lead-acid battery was manufactured. The positive electrode has a degree of oxidation of 70% (metal lead 3
(0%, 70% lead monoxide) lead powder and dilute sulfuric acid were kneaded to obtain an active material paste, which was then filled on both sides of the lattice as shown in FIG. The negative electrode has a degree of oxidation of 70% (metal lead 30%,
A small amount of carbon powder and lignin were added to lead powder of (70% lead monoxide) and kneaded with dilute sulfuric acid to obtain an active material paste, which was then filled on both sides of the lattice. The positive electrode 6 and the negative electrode 7 are interposed via the glass mat separator 5 with a diameter of 5 mm.
Was wound as shown in FIG. 5 to obtain a spiral electrode group.

As Example 1, a spiral electrode group having the same structure as that of the conventional example was obtained except that an active material non-holding portion having a width of 8 mm was formed at the winding start end of the positive electrode grid surface.

As Example 2, a spiral electrode group having the same structure as that of the conventional example was obtained except that an active material non-holding portion having a width of 8 mm was formed at the winding start end of the positive and negative electrode grid surfaces. .

In Example 3, an active material non-holding portion having a width of 8 mm was formed only on the inner side of the winding at the winding start end of both the positive and negative electrodes by using a grid whose rigidity was increased by adding 0.1 wt% of Ca. A spiral electrode group having the same configuration as that of the conventional example was obtained except that this was done.

After inserting the above-mentioned various spiral electrode plates into a cylindrical resin container and sealing the same, a dilute sulfuric acid aqueous solution having a predetermined specific gravity is injected from the injection port under reduced pressure at a constant current of 0.25 C for 40 hours. A battery case formation was performed to obtain a cylindrical lead-acid battery having a nominal capacity of 12 Ah. Each of these 20 cylindrical lead-acid batteries,
After discharging at a discharge rate of 0.2C, in order to evaluate the cycle life, 1C discharge (1.7V end voltage), 1C constant current ×
A charge / discharge cycle test of 2.45 V constant voltage charging (1.5 hours) was performed.

FIG. 11 shows the result. As is apparent from FIG. 11, according to the present invention, a cylindrical secondary battery having few internal short circuits and excellent cycle life performance is provided.

[0038]

As described above, a spiral electrode plate group is provided in which a positive electrode having a positive electrode active material held on a positive electrode substrate and a negative electrode having a negative electrode active material held on a negative electrode substrate are wound via a separator. In the cylindrical secondary battery, at least one of the positive and negative electrodes is a cylindrical secondary battery, in which an active material non-holding portion is formed at a winding start end of a substrate surface, and furthermore, In addition, the active material non-holding portion is about half a turn, the active material non-holding portion is only on the winding inner surface side,
According to the present invention to which the feature that the base is a lattice or the like is added, a short circuit due to softening or swelling of the active material at the center of the winding due to the progress of the charging / discharging cycle is reduced, and thus the cylindrical shape having good performance It has become possible to provide a secondary battery.

[Brief description of the drawings]

FIG. 1 shows an example of a base of a cylindrical secondary battery.

FIG. 2 shows an example of a base of a cylindrical secondary battery.

FIG. 3 is a view showing a conventional electrode plate of a cylindrical secondary battery.

FIG. 4 is a view showing a conventional electrode plate of a cylindrical secondary battery.

FIG. 5 is a diagram showing a method of manufacturing a spiral electrode group.

FIG. 6 is a diagram showing a spiral electrode group.

FIG. 7 is a diagram showing an example.

FIG. 8 is a diagram showing an example.

FIG. 9 is a diagram showing an example.

FIG. 10 is a diagram showing an example.

FIG. 11 is a diagram showing an example.

FIG. 12 is a diagram showing test results.

FIG. 13 is a diagram showing an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical bar 2 Horizontal bar 3 Ear 4 Square 5 Metal foil 6 Lead 7 Active material 8 Positive electrode plate 9 Negative electrode plate 10 Shaft 11 Separator 12 Active material non-holding portion at winding start end 16 Other electrode not in contact 17 Cavity 18 Unrolled winding start end

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 4/78 H01M 4/78 A

Claims (8)

[Claims] 1. A cylindrical type comprising a spiral electrode plate group in which a positive electrode having a positive electrode active material held on a positive electrode substrate and a negative electrode having a negative electrode active material held on a negative electrode substrate are wound with a separator interposed therebetween. In the secondary battery, at least one of the positive electrode and the negative electrode has an active material non-holding portion formed at a winding start end of a substrate surface. 2. The cylindrical secondary battery according to claim 1, wherein the active material non-holding portion is about half a turn. 3. The cylindrical secondary battery according to claim 1, wherein the active material non-holding portion is only on the inner side of the winding. 4. The cylindrical secondary battery according to claim 1, wherein the active material non-holding portion is not wound. 5. The cylindrical secondary battery according to claim 1, wherein the substrate is a lattice. 6. The cylindrical secondary battery according to claim 5, wherein no grid is formed in the active material non-holding portion. 7. The cylindrical secondary battery according to claim 1, wherein the substrate is a non-porous foil. 8. The method according to claim 1, wherein the positive electrode active material is mainly composed of lead dioxide, the negative electrode active material is mainly composed of lead, and the current collector is lead or a lead alloy. , 6 or 7
The cylindrical secondary battery as described in the above.