JP2002203591A - Cylindrical secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spiral electrode plate group with a sufficient cycle life performance and a cylindrical secondary battery equipped with it, by preventing a short circuit in a piling portion of an intersection of a crosspiece of a positive- electrode lattice and an intersection of a crosspiece of a negative-electrode lattice. SOLUTION: In the spiral electrode plate group which is wound with the positive electrode plate, which a positive-electrode active material is held in the positive-electrode lattice, and the negative-electrode plate, which a negative- electrode active material is held in the negative-electrode lattice, through separator, the spiral electrode plate group and the cylindrical secondary battery provided with it are constituted so that the intersection 75 of the crosspiece of the positive-electrode lattice and the intersections 85 of the crosspiece of the negative-electrode lattice may not overlap. By this, the danger of the short circuit can be reduced also in a high-pressuring state, and the cycle life performance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spirally wound electrode group and a cylindrical secondary battery having the same.

[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, 4 is a square, and 5 is an intersection between the vertical bar 1 and the horizontal bar 2. . Then, the active material is held in such a grid by coating or filling to form an electrode plate.

FIG. 2 is a schematic view showing a winding method for forming such a spiral electrode group, wherein a half-split shaft body 6 is used.
The positive electrode plate 7 and the negative electrode plate 8 are wound via a separator 9. The spirally-wound electrode group thus obtained is housed in a container, and a known operation is performed to obtain a cylindrical secondary battery including the spirally-wound electrode group.

[0012] At this time, a conventional cylindrical secondary battery provided with a spirally wound electrode plate group in which an active material is held on a grid generally uses a grid having the same positive and negative shapes. In general, secondary batteries have the characteristic that when repeated charging and discharging, the active material softens or swells and battery performance decreases,
The spirally wound electrode group is also wound in such a state that high pressure is applied.

[0013]

However, in the case of a casting grid, the vicinity of the intersection between the vertical bar and the horizontal bar is schematically shown in FIG.

In FIG. 3, 1 is a vertical beam, 2 is a horizontal beam, 11
Is the ridge of the vertical bar, 22 is the ridge of the horizontal bar 2, 5 is the intersection of the vertical bar 1 and the horizontal bar 2, and 55 is the intersection of the two ridges 11, 22. Naturally, the intersection 5 has a higher strength than the vertical rail 1 and the horizontal rail 2, and when a compressive force is applied from the electrode plate surface direction, the deformation amount is smaller than that of the rail. Therefore, a state as shown in FIG. 4 occurs in a portion where the intersection of the positive grid and the intersection of the negative grid overlap.

FIG. 4 is a schematic cross-sectional view showing one positive electrode, a separator and a negative electrode of a group of electrode plates wound in a high pressure state, wherein 71 is a positive electrode grid, 81 is a negative electrode grid, 9 is a separator, 75 Is the intersection of the bars of the positive grid, 85 is the intersection of the bars of the negative grid, and F is the pressing force acting on the electrode plate surface. The illustration of the active material is omitted. As described above, the intersection point 75 of the bars of the positive electrode grid 71 and the intersection point 85 of the bars of the negative electrode lattice 81 are unlikely to be deformed and protrude from each other. For this reason, there is a problem that a short circuit is likely to occur in this portion as the charge / discharge cycle progresses.

In the case of a punched grid, although the whole is flat without a ridge like a cast grid, it is necessary to make the whole thin, and the positive and negative grid bars are almost overlapped via a thin separator. In a high pressure state, there is a problem that the interval between the grids of the positive and negative grids is narrowed, and a short circuit is easily generated at the portion between the grids.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a positive electrode plate holding a positive electrode active material on a positive electrode grid and a negative electrode plate holding a negative electrode active material on a negative electrode grid. In a spirally wound electrode group wound with a separator interposed therebetween, a spirally wound electrode group capable of reducing the risk of a short circuit even in a high-pressure compression state, and a cylindrical secondary battery including the same are provided. is there.

[0018]

According to a first aspect of the present invention, there is provided a positive electrode plate having a positive electrode active material held by a positive electrode grid and a negative electrode plate having a negative electrode active material held by a negative electrode lattice. A spiral electrode group wound around a separator, wherein the intersections of the bars of the positive electrode grid and the intersections of the bars of the negative electrode lattice are configured not to overlap with each other. .

A second invention according to the first invention, 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. A third invention which is a group of electrode plates is a cylindrical secondary battery provided with the spiral electrode group according to the first or second invention.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION A first aspect of the present invention is a spiral structure in which a positive electrode plate holding a positive electrode active material on a positive electrode grid and a negative electrode plate holding a negative electrode active material on a negative electrode lattice are wound via a separator. In the electrode plate group, the intersection of the bars of the positive grid and the intersection of the bars of the negative grid are configured not to overlap.

FIG. 5 is a schematic view showing an example of a spiral electrode plate group according to the present invention, showing only a positive electrode grid and a negative electrode grid.
Numeral 1 denotes a positive grid, 81 denotes a negative grid, 75 denotes an intersection of the positive grid, and 85 denotes an intersection of the negative grid. The frame of the negative grid (the vertical and horizontal rails at the periphery of the grid) is hidden by the frame of the positive grid, and the ears of the negative grid are not shown. By adopting such a configuration, it is possible to prevent the intersection of the bars of the positive electrode grid and the intersection of the bars of the negative electrode grid from being close to each other even in the spiral electrode group in a high pressure pressing state using a casting grid. Therefore, it is possible to prevent a short circuit at the intersection between the bars.

As shown in FIG. 1, when the positive electrode grid and the negative electrode grid are wound in a state of being substantially overlapped with each other, the cross section of the positive grid and the cross section of the negative grid are corresponded to each other by “surface”. However, as shown in FIG. 5, except for the frame portion, the bars of the positive electrode grid and the bars of the negative electrode grid are opposed to each other at "points". Sex can be greatly reduced.

In FIG. 5, all the intersections of the bars except for the frame are shown so as not to overlap. However, the present invention is not necessarily limited to this state. If at least half of the intersections are configured not to overlap. In the present invention, at least half of the intersections do not overlap, so that the intersection of the positive grid and the intersection of the negative grid do not overlap.
Shall be done. In addition, the number and size of the bars, the number and size of the cells, the size and material of the grid, the type and application amount of the active material, the pressing force, the material and size of the separator, and the like are design items that can be appropriately selected. In addition, the method of manufacturing the lattice is not limited to casting and punching.

A second invention according to the first invention, 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. It is a group of electrode plates. This makes it possible to prevent the intersection of the bars of the positive electrode grid and the intersection of the bars of the negative electrode grid from approaching each other even in the spirally wound electrode group for a lead-acid battery in a high pressure state. A short circuit at a portion can be prevented.

According to a third aspect, there is provided a cylindrical secondary battery provided with the spirally wound electrode group according to the first or second aspect. As a result, it is possible to prevent the intersection of the cross section of the positive grid and the cross section of the cross section of the negative grid from approaching each other. A battery is provided.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a specific gravity of 11.3 g /
A lattice was manufactured by a casting method using cc non-antimony lead alloy foil. Grid dimensions are 0.6mm thick x 80m wide
A vertical bar 1 of mx 500 mm in length and 1.5 mm in width, a horizontal bar 2 of 1.5 mm in width, and a grid of (length) 5 mm x (width) 7 mm were uniformly arranged. Note that pure lead may be used instead of the non-antimony lead alloy.

Next, as the second grid, the material, the outer dimensions, the crosspiece size, and the dimensions of the other grids except for the grids of the outer peripheral portion are the same as those of the first grid, but the dimensions of the grids of the outer peripheral portion are changed. When the first grid was overlapped with the first grid, the intersection of the bars of the second grid was positioned substantially at the center of the square of the first grid.

Next, a conventional spiral electrode group was manufactured in the following procedure. First, a lead powder having an oxidation degree of 70% (metal lead 30%, lead monoxide 70%) and dilute sulfuric acid are kneaded to obtain an active material paste, which is then filled on both surfaces of the first lattice to form a positive electrode plate. It was created. Next, a slight amount of carbon powder and lignin were added to lead powder having a degree of oxidation of 70% (metal lead 30%, lead monoxide 70%) and kneaded with dilute sulfuric acid to obtain an active material paste. Both sides of the first grid were filled. These positive electrode 6 and negative electrode 7
Were wound through a glass mat separator 5 using a core having a diameter of 5 mm as shown in FIG. 2 to obtain a spiral electrode group.
The pressure at this time was 200 kPa.

As an example, a spiral electrode group similar to the conventional example was manufactured except that the second grid was used as the positive grid.

After inserting the above two kinds of spiral electrode plates into a resinous cylindrical container and sealing it, a dilute sulfuric acid aqueous solution having a predetermined specific gravity is injected from the injection port under reduced pressure, and at a constant current of 0.25 C. The battery case was formed for 40 hours to obtain a cylindrical lead-acid battery having a nominal capacity of 10 Ah. After discharging each of these 20 cylindrical lead-acid batteries at a discharge rate of 0.2 C, to evaluate the cycle life, 1 C discharge (1.7 V end voltage), 1 C constant current × 2.45 V constant voltage A charge / discharge cycle test of charging (1.5 hours) was performed.

FIG. 6 shows the result. As is apparent from FIG. 6, according to the present invention, a cylindrical secondary battery having few internal short circuits and excellent cycle life performance is provided.

[0032]

As described above, in a spirally wound electrode plate group in which a positive electrode plate holding a positive electrode active material on a positive electrode grid and a negative electrode plate holding a negative electrode active material on a negative electrode lattice are wound via a separator, The spiral electrode group, which is configured so that the intersection point of the cross section of the positive grid and the cross point of the cross section of the negative grid do not overlap, and the cylindrical secondary battery including the same, It has become possible to provide a spirally wound electrode group capable of reducing the risk of a short circuit even in a state, and a cylindrical secondary battery including the same.

[Brief description of the drawings]

FIG. 1 shows a grating.

FIG. 2 is a diagram illustrating a method of manufacturing a spiral electrode group.

FIG. 3 is a diagram showing intersections of grid bars.

FIG. 4 is a diagram showing a conventional example.

FIG. 5 is a diagram showing an example.

FIG. 6 is a diagram showing test results.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical beam 2 Horizontal beam 4 square 8 Positive electrode plate 9 Negative electrode plate 10 Shaft body 11 Separator 75 Intersection of crossing of positive electrode grid 85 Intersection of crossing of negative electrode grid

Claims (3)

[Claims] A spiral electrode plate group in which a positive electrode plate having a positive electrode active material held on a positive electrode grid and a negative electrode plate having a negative electrode active material held on a negative electrode lattice are wound through a separator. A spiral electrode plate group, wherein the intersection of the bars of the cross-section and the intersection of the bars of the negative electrode grid do not overlap with each other. 2. The spiral electrode group 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. 3. A cylindrical secondary battery comprising the spirally wound electrode plate group according to claim 1.