JP2001143712A - Cylindrical secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical secondary battery improved in current collecting and excellent in discharging performance. SOLUTION: The cylindrical secondary battery includes a spiral electrode plate, in which a positive electrode having a positive electrode active material and a positive current collection electrode, and a negative electrode having a negative electrode active material and a negative current collection electrode, are wound intervening a separator therebetween. At least one side of the collection electrodes has plural electrode plate ears and gaps all formed on the collection electrodes. Also, the porosity of a winding end of the collection electrodes is smaller than that of a winding start.

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. The lead storage 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. The 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, and has an operating voltage of about 1.2V. 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. . The 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 electrolyte, and has an operating voltage of about 1.2V. It has a high energy density and has been put to practical use mainly in various consumer devices. The silver zinc oxide battery uses silver oxide as a positive electrode active material, zinc as a negative electrode active material, and potassium hydroxide as an 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. Lithium-ion batteries use LiCoO2, LiNiO
2. A Li metal composite oxide such as 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. Practical secondary batteries as described above are provided in the form of a square, a cylinder, a button, a sheet, or the like depending on the application.

[0003]

As is well known, a cylindrical secondary battery is provided with an electrode group in which a positive electrode and a negative electrode are spirally wound with a separator interposed therebetween. Demand for various applications is increasing.

There are various methods for collecting current for a battery having a spiral electrode group, and one of them is to provide a so-called current collecting ear. In this case, mere provision of a single plate lug in spite of the length in the winding direction increases the internal resistance, and the active material in a portion away from the lug cannot be sufficiently used. 175379 and JP-A-10-13479
As disclosed in No. 4, a plurality of current collecting ears are formed on a current collector to prevent an increase in internal resistance, thereby effectively utilizing an active material. Further, if a plurality of current collecting ears are arranged irregularly as shown in FIG. 1, it becomes difficult to connect to external terminals. Therefore, a configuration in which the current collecting ears are arranged regularly as shown in FIG. 2 is employed.

In order to arrange the current collecting ears 2 regularly as shown in FIG. 2, naturally, as shown in FIG. 3, the distance between the current collecting ears located at the center of the spiral and the outer side of the current collecting ears is increased. It is necessary to increase the distance between the electrical ears, and the outer collector ear 2b on the outer side of the spiral current collector 2b has to have a wider electrode area to be collected. For this reason, there is still a problem in that the utilization of the active material is unbalanced, and the capacity and the rapid discharge performance are reduced.

In order to improve the current collection performance, as shown in FIG.
It is known from JP-A-62-47962 and 47963 to reduce the void area in the direction of the current collector weld, but attention is paid to the problem of how to improve the resistance at the winding end side of the current collector. There is no example. The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to achieve uniform use of an active material and thereby improve capacity reduction and rapid discharge performance reduction. It is to provide a secondary battery.

[0007]

The means for solving the problems will be described below with reference to the drawings. The invention according to claim 1 is a spiral electrode plate in which a positive electrode including a positive electrode active material and a positive electrode current collector and a negative electrode including a negative electrode active material and a negative electrode current collector are wound via a separator 30. In a cylindrical secondary battery including a group, at least one of the current collectors includes a current collector body 1, a plurality of current collector ears 2 formed in the current collector body, and a gap formed in the current collector body. And a porosity on the winding end side Y of the spirally wound electrode plate group of the current collector body is smaller than a porosity on the winding start side X.

With such a structure, a cylindrical secondary battery is provided in which the electric resistance at the winding end side of the current collector body is further reduced, so that the active material can be used uniformly, and the capacity and the rapid discharge performance are improved. can do.

The porosity means the ratio of the cavities 3 in the current collector body 1. Further, assuming that the porosity on the winding end side of the spirally wound electrode group of the current collector body 1 is smaller than the porosity on the winding start side, at least as shown in FIG. The current collector main body is divided into two in the longitudinal direction, and the area of about one half of the winding start side of the current collector main body is A1, and the area of the winding end side is about 2 times.
The area of one half is defined as A2, and the area of the void portion of the A1 portion is defined as B.
1, when the area of the void portion of the A2 portion is B2, (B1 /
A1)> (B2 / A2). Hereinafter, if necessary, the area is divided into three, and the area of about one third on the winding start side of the current collector main body is AA1, and the area of about one third of the middle part is AA1.
2. Approximately one third of the area on the winding end side is designated as AA3.
Assuming that the void area of one part is BB1, the void area of the AA2 part is BB2, and the void area of the AA3 part is BB3, (BB1 / AA1)> (BB2 / AA2)> (BB
3 / AA3), and thereafter, it is sufficient to make the value smaller toward the end of the winding, such as 4 minutes, 5 minutes, etc. in a macroscopic manner.
Meaning micro comparison such as 000 division,
It does not mean the size of individual voids.

According to a second aspect of the present invention, as shown in FIGS. 6 and 7, the current collector body 1 is composed of an outer frame bar 4, a vertical bar 5, and a horizontal bar 6,
The gap portion 3 is formed in a grid shape by the outer frame bar 4, the vertical bar 5, and the horizontal bar 6. With this configuration, it is possible to provide the cylindrical secondary battery having the current collector easily formed by punching or the like.

According to a third aspect of the present invention, as shown in FIG. 6, the current collector body 1 is composed of an outer frame bar 4, a vertical bar 5, and a horizontal bar 6, and the gap 3 is formed by the outer frame bar 4 and the vertical bar 5. In the cylindrical secondary battery formed in a grid pattern with the horizontal rails 6, the interval between the vertical rails of the current collector body is smaller at the winding end side Y of the spiral electrode group than at the winding start side X. And

Thus, even if the width of the vertical rails 5 (the length of the vertical rails in the length direction of the current collector) is the same, the number of the vertical rails 5 on the winding end side Y becomes larger than that on the winding start side X. Provided is a cylindrical secondary battery in which the area of the void portion 3 occupying the area is reduced, the electric resistance at the winding end side is further reduced, the use of the active material is made uniform, and the capacity and the rapid discharge performance are improved. be able to.

It is to be noted that, as described above, the current collector main body 1 is defined in such a manner that the vertical bar interval of the current collector main body is smaller than the winding start side X of the spirally wound electrode plate group at the winding end side Y. When the area of about half of the winding start side of the current collector body is A1 and the area of about half of the winding end side is A2, (the number of vertical bars included in the A1 part) <(A2 part) Included vertical berths)
Means that Then, if necessary, divide it into 3 minutes,
Approximately one third of the area on the winding start side of the current collector body is AA1,
Assuming that the area of about one third of the middle part is AA2 and the area of about one third on the winding end side is AA3, (number of vertical rails of AA1 part) <(number of vertical rails of AA2 part) <(AA3 The number of vertical cross sections of the part), and the following four parts, five parts, etc. are compared macroscopically, and the larger the end part of the winding, the better.
It means a micro comparison like 1000 minutes,
It does not mean the size of the space between individual crossbars.

According to a fourth aspect of the present invention, as shown in FIG. 7, the current collector body 1 is composed of an outer frame bar 4, a vertical bar 5, and a horizontal bar 6, and a gap 3 is formed between the outer frame bar 4 and the vertical bar 5. In the cylindrical secondary battery formed in a grid shape with the horizontal rail 6 and the horizontal rail 6, the width of the vertical rail E2 on the winding end side Y of the current collector body is larger than the vertical rail width E1 on the winding start side X. It is assumed that. Thus, even if the number of vertical rails per unit area is the same, the area occupied by the vertical rails on the winding end side is larger than on the winding start side, and the area of the void portion 3 in the unit area is reduced. As a result, it is possible to provide a cylindrical secondary battery in which the use of the active material is made uniform and the capacity and the rapid discharge performance are improved.

It is to be noted that the fact that the vertical rail width on the winding end side Y of the current collector main body is larger than the vertical rail width on the winding start side X is at least divided into two in the length direction. Assuming that the area of about half of the winding start side of the current collector body is A1 and the area of about half of the winding end side is A2, (the total length of the vertical rail included in the A1 portion) < (The total vertical beam width included in the A2 portion). Hereafter, as necessary
AA1 is the area of about one third on the winding start side of the current collector body, AA2 is the area of about one third of the middle part, and AA3 is the area of about one third on the winding end side of the current collector body. When you do, (AA
The total vertical width of one part) <(the total vertical width of AA2 part) <(the total vertical width of AA3 part)
Minutes, 5 minutes, etc., may be compared macroscopically, and may be larger at the end of the winding, but may mean a microscopic comparison such as 100 divisions, 1000 divisions, or the magnitude of each vertical rail width. Not.

The invention of claim 5 is characterized in that, as shown in FIGS. 8 and 10, the current collector body 1 is a foil and the voids are circular holes 3k to 3p formed in the foil. Thus, the cylindrical secondary battery having an easy and inexpensive current collector can be provided. The circular hole is not limited to a true circular hole, but may be an elliptical hole.

According to a sixth aspect of the present invention, in the cylindrical secondary battery, wherein the current collector body 1 is a foil and the voids 3 are circular holes formed in the foil, the circular hole diameter is a spiral pole. The winding end side Y of the plate group is smaller than the winding start side X.

Thus, even if the number of circular holes per unit area of the current collector main body is the same, the void area on the winding end side Y of the spirally wound electrode plate group of the current collector main body becomes larger than the void area on the winding start side X. It is possible to provide a cylindrical secondary battery which is smaller than the area, can achieve uniform use of the active material, and has improved capacity reduction and rapid discharge performance reduction.

It is to be noted that that the circular hole diameter is smaller at the winding end side than at the winding start side of the spiral electrode group, at least the current collector main body is divided into two in the longitudinal direction, and the current collector main body is formed as described above. When the area of about one half of the winding start side is A1 and the area of about one half of the winding end side is A2, (average diameter of the circular hole in the A1 part)> (circular hole in the A2 part) Mean diameter). Thereafter, if necessary, it is divided into three, and the area of about one-third of the winding start side of the current collector body is AA1, the area of about one-third of the middle part is AA2, and the area of the winding end is about three minutes. Assuming that the area of 1 is AA3, (Average diameter of circular hole in AA1 part)> (Average diameter of circular hole in AA2 part)> (Average diameter of circular hole in AA3 part); Minutes, 5 minutes, etc. may be compared macroscopically, and the smaller the end portion of the winding, the smaller it may be, but it means a microscopic comparison such as 100 divisions, 1000 divisions, or the size of each circular hole diameter. Not.

According to a seventh aspect of the present invention, there is provided the cylindrical secondary battery as shown in FIG. 10, wherein the current collector main body is a foil and the void portion is a circular hole formed in the foil. The winding end side Y of the spiral electrode group is smaller in number density than the winding start side X. Thereby, even if the circular hole diameter is the same, the void area on the winding end side of the spirally wound electrode plate group of the current collector main body is made smaller than the void area on the winding start side, and uniform use of the active material can be achieved. It is possible to provide a cylindrical secondary battery with improved capacity reduction and rapid discharge performance reduction.

The term "circular hole density" means the number of circular holes included in a unit area. The phrase "the winding end side is smaller than the winding start side" means that at least the current collector body having a length L is longer than the length. Assuming that the area of about half of the winding start side of the current collector body is A1 and the area of about half of the winding end side is A2 as described above, (number of circular holes in A1 portion)> (The number of circular holes in the A2 portion). Thereafter, if necessary, the area is divided into three parts, and the area of about one third of the winding start side of the current collector body is AA.
1. When the area of about 1/3 of the middle part is AA2 and the area of about 1/3 of the winding end side is AA3, (number of circular holes in AA1 part)> (number of circular holes in AA2 part)> (The number of circular holes in the AA3 portion), and it is sufficient to make it smaller at the end portion of the winding in a macroscopic manner such as 4 minutes, 5 minutes, etc.
It does not mean a micro comparison such as 1000 divisions.

According to the invention of claim 8, in the cylindrical secondary battery, P is the mass of the active material per unit area of the current collector body, and G is the mass of the current collector body per unit area of the current collector.
It is characterized in that the value of G / P is larger on the winding end side of the spiral electrode group than on the winding start side.

According to this, if the mass of the active material at the beginning and the end of the winding is the same, the mass of the current collector body at the end of the winding is large. Since the mass of the current collector is large and the electric resistance is small, uniform use of the active material can be achieved, and thus a cylindrical secondary battery with reduced capacity and reduced rapid discharge performance can be provided.

The mass of the active material per unit area of the current collector is P
And the mass of the current collector body per unit area is G,
When the value of G / P is larger at the winding end side than at the winding start side of the spiral electrode group, at least the current collector body having the width W and the length L is divided into two in the length direction, Approximately half the area on the winding start side of the conductor body is A1, and half the area on the winding end side is A2.
The mass of the current collector body in the A1 portion is C1, the mass of the current collector body in the A2 portion is C2, and the mass of the active material in the A1 portion is D.
1, when the mass of the active material in the A2 portion is D2, (C1 /
D1) <(C2 / D2). Thereafter, if necessary, the current is similarly divided into three, and the area of about 1/3 of the winding start side of the current collector main body is AA1, and the area of about 1/3 of the intermediate portion is AA1.
A2, AA3 is the area of about 1/3 of the winding end side,
The mass of the current collector body of one portion is CC1, the mass of the current collector body of the AA2 portion is CC2, the mass of the current collector body of the AA3 portion is CC3, the mass of the active material of the A1 portion is DD1, and the mass of the active material of the A2 portion is DD1. Assuming that the mass of the substance is DD2 and the mass of the active material in the portion of AA3 is DD3, (CC1 / DD1) <(CC2 / D
D2) <(CC3 / DD3), hereinafter, can be made larger by macro comparison such as 4 minutes, 5 divisions, etc.
It does not mean a micro comparison, such as minutes, 1000 minutes.

A ninth aspect of the present invention is characterized in that the positive electrode active material is lead dioxide, the negative electrode active material is lead, and the current collector is lead or a lead alloy. Thereby, a suitable cylindrical lead storage battery can be provided. A known configuration may be adopted for other components such as an electrolytic solution, a separator, and a battery case that constitute the cylindrical lead-acid battery.

According to a tenth aspect of the present invention, the positive electrode active material is a composite oxide of lithium and another metal, the positive electrode current collector is aluminum or an aluminum alloy, the negative electrode active material is a carbonaceous material,
The negative electrode current collector is made of copper or a copper alloy. Thereby, a suitable cylindrical lithium ion secondary battery can be provided. A known configuration may be adopted for other components such as an electrolytic solution, a separator, and a battery case that constitute the cylindrical lithium ion secondary battery.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 9 is a view showing an overview of a spirally wound electrode plate group, wherein 12 is a current collecting ear of a positive electrode current collector, and 17 is a chargeable / dischargeable positive electrode active material applied to the positive electrode current collector. Material, 22 is a current collecting ear of the negative electrode current collector, 27 is a chargeable / dischargeable negative electrode active material applied to the negative electrode current collector, 30 is a separator, and these positive and negative electrodes are wound through the separator. Thus, a spiral electrode group 40 is obtained. The spiral electrode group 40 is housed in a cylindrical battery container, and connected to output terminals by known means.
A cylindrical secondary battery is obtained by performing sealing, injection, and the like.

In the spiral electrode group 40, the current collecting ears 12 of the positive electrode current collector and the current collecting ears 22 of the negative electrode current collector are regularly arranged, so that an output terminal (not shown) is provided. Connection is easily made.

The present invention provides a new knowledge of the preferred current collector structure and the preferred relationship between the mass of the active material per unit area and the mass of the current collector body in a cylindrical secondary battery provided with a spiral electrode group. Accordingly, it is an object of the present invention to provide a cylindrical secondary battery in which the active material is used uniformly and the capacity and the rapid discharge performance are improved.

[0030]

EXAMPLES Various current collectors shown below were weighed at 11.3 g.
/ Cc by using a non-antimony lead alloy foil. The size of the current collector is thickness 0.6mm x width 80
mm × 500 mm in length. Note that the current collector may be formed of pure lead instead of a non-antimony lead alloy.

FIG. 3 is a schematic view showing a conventional example, and has a width of 1.5.
mm vertical rail 5 and 1.5 mm wide horizontal rail 6 and (vertical) 5 mm ×
(Horizontal) 7 mm squares 3 are evenly arranged. The porosity in the current collector body was 61%. The current collector body mass was 106 g.

FIG. 5 is a schematic diagram showing the first embodiment, in which a 1.5 mm wide vertical bar 6 and a 1.5 mm wide
5 mm (horizontal) and 5 mm (vertical) × 7 mm (horizontal) mesh 3a
Are arranged evenly, and the width is 1.5 from the middle to the end of the winding.
mm vertical rail 6 and 1.5 mm wide horizontal rail 5 and (vertical) 5 mm ×
A (horizontal) grid 3b of 5 mm is a current collector evenly distributed, and the interval between vertical rails is smaller at the half of the winding end side than at the half of the winding start side. According to this, the void area is reduced from the middle part to the end of winding because the number of vertical rails increases, so that the porosity of the current collector body on the winding end side is smaller than the porosity on the winding start side. It can be.

It should be noted that the porosity is 61
%, 57%. The mass of each section was 53 g and 58 g in order from the winding start side.

FIG. 6 is a schematic diagram showing the second embodiment.
While the vertical rail 5 of 5 mm and the horizontal rail 6 of 1.5 mm are the same, the first one-fifth part (about 94 mm in length) in the length direction of the current collector from the winding start side is (vertical) 5 mm × (horizontal) The 7 mm squares 3 c are evenly arranged, and the next approximately one-fifth part (length about 105 mm) is 5 mm (vertical) × 6 mm (horizontal) squares 3 d
Are arranged uniformly, and thereafter, (vertical) 5 mm × (horizontal) 5
3mm (section length about 98mm), 5mm (vertical)
× (horizontal) 4mm grid 3f (section length about 99mm),
In a part (approximately 104 mm in length) on the winding end side, 3 g of 5 mm (vertical) × 3 mm (horizontal) grids are uniformly arranged.

According to this, in the unit section divided into approximately five in the length direction, the number of vertical rails increases and the void area decreases as the grid becomes narrower. The porosity on the winding end side of the plate group can be smaller than the porosity on the winding start side.

The porosity is 61 in order from the winding start side.
%, 60%, 58%, 55% and 50%. Also,
The mass of each section is 20 g, 2
They were 3 g, 22 g, 24 g, and 28 g.

FIG. 7 is a schematic view showing the third embodiment, in which about one-third of the current collector from the winding start side (length of about 1/3).
63 mm), a 1.5 mm wide vertical rail 5a, a 1.5 mm wide horizontal rail 6 and a (longitudinal) 5 mm × (horizontal) 7 mm grid 3h are evenly arranged, and about one-third of the middle part (length) About 161m
m) is a vertical bar 5b having a width of 2.0 mm and a horizontal bar 6 having a width of 1.5 mm.
And 3 mm of (length) 5 mm x (width) 6.5 mm are evenly distributed, and about one-third of the winding end side (length of about 176 m)
m) is a vertical bar 5c of 2.5 mm width, a horizontal bar of 1.5 mm width and 6
And grids 3j of (vertical) 5 mm × (horizontal) 6 mm are evenly arranged. According to this, in the unit section divided into three in the length direction, the section in which the width of the vertical rail is increased has a smaller grid and a reduced void area, so that the winding of the spiral electrode group of the current collector body is reduced. The porosity on the end side can be smaller than the porosity on the start side of winding.

The porosity is 61 in order from the winding start side.
%, 57%, and 51%, and the mass of each section was 34, 38 g, and 47 g in order from the winding start side.

FIG. 8 is a schematic diagram showing the fourth embodiment, in which about a quarter (length about 128) in the length direction of the current collector from the winding start side.
mm), perforations 3k having a diameter of 5.5 mm are equally arranged in 11 rows and 18 columns, and the next approximately quarter portion (length of approximately 12 mm) is provided.
2 mm), 3 l of 5.0 mm diameter perforations are 11 rows and 18
The holes are evenly arranged in a row, and in the next approximately one-quarter portion (about 122 mm in length), a perforated 3 m having a diameter of 4.5 mm is provided.
Equally arranged in one row and 18 columns, about one quarter of the end of the winding
In the section (length: about 128 mm), perforations 3n having a diameter of 4.0 mm are equally arranged in 11 rows and 18 columns. According to this, in the unit section divided into four in the length direction, the void area is reduced by the decrease in the hole diameter, so that the porosity on the winding end side of the spirally wound electrode plate group of the current collector body is reduced. It can be smaller than the porosity at the beginning.

The porosity is 46% in order from the winding start side,
39%, 32%, and 24%, and the mass of each section was 37 g, 40 g, 45 g, and g in order from the winding start side.

FIG. 10 is a schematic view showing the fifth embodiment, in which about one-fourth of the current collector length direction (length of about 12
Up to 8 mm), 11 holes 18 with 5.5 mm diameter perforations 3p
The rows are evenly arranged (only a part of the perforation is shown in the figure. The same applies to the following), and the next approximately one-fourth portion (length about 12
2 mm), the perforations 3p having the above-mentioned diameters are equally arranged in 9 rows and 18 columns, and the next approximately quarter portion (length of approximately 12 mm) is provided.
2 mm), the perforations 3p having the above-mentioned diameters are evenly arranged in 7 rows and 18 columns, and about a quarter (length about 1
28 mm), the perforations 3p having the above-mentioned diameters are equally arranged in a diameter of 5 rows and 18 columns. According to this, 4 in the longitudinal direction
In the divided unit section, the void area is reduced as the number of perforations is reduced, so that the porosity on the winding start side of the spiral electrode group of the current collector body is larger than the porosity on the winding end side. be able to.

The porosity is 46 in order from the winding start side.
%, 39%, 31%, and 21%, and the weight of each section is 37 g, 40 g, 46 g, 5 g in order from the winding start side.
It was 5 g.

Using the various current collectors described above, cylindrical sealed lead-acid batteries were manufactured. The positive electrode has an oxidation degree of 70% (metal lead 30
%, 70% lead monoxide) and dilute sulfuric acid to obtain an active material paste, which was then applied to both surfaces of the current collector. At this time, the applied amount is the apparent surface area 1 of the positive electrode current collector main body.
The theoretical capacity per cm 2 was 30 mAh.

The negative electrode was prepared by adding a slight amount of carbon powder and lignin to lead powder having a degree of oxidation of 70% (metal lead 30%, lead monoxide 70%) and kneading with dilute sulfuric acid to obtain an active material paste. These were applied to both sides of the current collector. At this time, the applied amount is calculated based on the theoretical capacity per 1 cm 2 of the apparent surface area of the negative electrode current collector main body.
mAh.

In the above embodiment, the active material was uniformly applied to the current collector body, P was the mass of the active material per unit area, and G was the mass of the current collector body per unit area. At this time, the value of G / P is larger on the winding end side of the spiral electrode group than on the winding start side.

A spiral electrode group 40 was obtained from these positive and negative electrodes via the glass mat separator 30 as shown in FIG.

Next, after inserting the spirally wound electrode plate group into a cylindrical resin container and sealing the same, a dilute sulfuric acid aqueous solution having a predetermined specific gravity is injected through the injection port under reduced pressure, and the solution is supplied at a constant current of 0.25 C. A battery case formation was performed for an hour to obtain a cylindrical sealed lead storage battery.

[0048] These cylindrical sealed lead-acid batteries were
Discharge was performed at a discharge rate of C. In order to further evaluate the cycle life, 1C discharge (1.7 V cutoff voltage), 1C constant current ×
A charge and discharge cycle test of 2.45 V constant voltage charge (1.5 hours) was performed. FIG. 11 shows a discharge test result at a discharge rate of 0.2 C, and FIG. 12 shows a cycle life test result.
In these figures, i, b, c, d, e, f
These are the results of Conventional Example, Example 1, Example 2, Example 3, Example 4, and Example 5, respectively.

From these results, it is found that a spiral electrode group in which a positive electrode provided with a positive electrode active material and a positive electrode current collector and a negative electrode provided with a negative electrode active material and a negative electrode current collector are wound via a separator. In the cylindrical sealed lead-acid storage battery provided with the current collector, the current collector body and a plurality of electrode lugs formed in the current collector body and the porosity of the current collector winding end side void space on the winding start side It can be seen that when the ratio is smaller than the ratio, a cylindrical sealed lead-acid battery having improved current collector resistance, reduced capacity and reduced rapid discharge performance is provided.

Further, when the porosity on the winding end side of the spirally wound electrode plate group of the current collector body is made larger than the porosity on the winding start side and the active material is uniformly applied to the current collector body, Assuming that the mass of the active material per area is P and the mass of the current collector body per unit area is G, the value of G / P is larger at the winding end side of the spiral electrode group and at the winding start side, and the winding end is larger. Also on the side, the utilization rate of the active material can be increased.

In the above-described embodiment, the positive and negative current collectors used were those in which the porosity at the winding start side of the spirally wound electrode plate group of the current collector body was larger than the porosity at the winding end side. Even if only one of the current collectors is used as described above, the performance is improved as compared with the conventional cylindrical secondary battery.

Although the above embodiment relates to a cylindrical lead-acid battery, the same effect is obtained when the positive electrode active material is a composite oxide of lithium and another metal, the positive electrode current collector is aluminum or an aluminum alloy, and the negative electrode active material is It was also confirmed in a cylindrical lithium ion secondary battery in which the carbonaceous material and the negative electrode current collector were copper or a copper alloy. The same effect was obtained in a cylindrical alkaline secondary battery and the like.

[0053]

As described above, a spiral electrode plate in which a positive electrode provided with a positive electrode active material and a positive electrode current collector and a negative electrode provided with a negative electrode active material and a negative electrode current collector are wound via a separator. In a cylindrical secondary battery including a group, at least one of the current collectors includes a current collector body, a plurality of electrode lugs formed in the current collector body, and a gap formed in the current collector body. The present invention of a cylindrical secondary battery, characterized in that the porosity at the winding start side of the spirally wound electrode group of the current collector body is larger than the porosity at the winding end side, and the current collector Assuming that the mass of the active material per unit area of the main body is P and the mass of the current collector body per unit area is G, the value of G / P is larger at the winding end side of the spiral electrode group at the winding start side. According to the present invention, a cylindrical secondary battery having excellent rapid discharge performance and cycle life performance It is possible to provide.

[Brief description of the drawings]

FIG. 1 is a schematic view of a spiral electrode group.

FIG. 2 is a schematic view of a spiral electrode group.

FIG. 3 shows a current collector having a current collector body, a plurality of electrode lugs formed in the current collector body, and a void formed in the current collector body of a conventional cylindrical secondary battery. It is a schematic diagram.

FIG. 4 is a schematic view showing a current collector for a spiral electrode group having a current collector main body and a plurality of electrode lugs formed on the current collector main body.

FIG. 5 is a schematic diagram showing a current collector according to Example 1 of the present invention.

FIG. 6 is a schematic diagram illustrating a current collector according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a current collector according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram showing a current collector according to Example 4 of the present invention.

FIG. 9 is a schematic view showing a spiral electrode group.

FIG. 10 is a schematic diagram showing a current collector according to Example 5 of the present invention.

FIG. 11 is a diagram showing test results.

FIG. 12 is a diagram showing test results.

FIG. 13 is a diagram illustrating an example of a conventional current collector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Current collector main body 2 Current collecting ear 3 Void part 4 Outer frame bar 5 Vertical bar 6 Horizontal bar

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 10/40 H01M 10/40 Z // H01M 4/14 4/14 Q

Claims (10)

[Claims] A spiral electrode group in which a positive electrode having a positive electrode active material and a positive electrode current collector and a negative electrode having a negative electrode active material and a negative electrode current collector are wound with a separator interposed therebetween. In the cylindrical secondary battery, at least one of the current collectors has a current collector body, a plurality of current collecting ears formed in the current collector body, and a void formed in the current collector body. And a porosity at the winding end side of the current collector body is smaller than a porosity at the winding start side. 2. The current collector body comprises an outer frame bar, a vertical bar, and a horizontal bar, and a gap is formed in a grid pattern by the outer frame bar, the vertical bar, and the horizontal bar. The cylindrical secondary battery according to claim 1. 3. The cylindrical secondary battery according to claim 2, wherein the vertical cross section of the current collector body is smaller at the winding end side of the spiral electrode group than at the winding start side. 4. The cylindrical secondary battery according to claim 2, wherein the width of the vertical cross section of the current collector body is larger at the winding end side of the spiral electrode group than at the winding start side. 5. The cylindrical secondary battery according to claim 1, wherein the current collector body is a foil, and the void is a circular hole formed in the foil. 6. The cylindrical secondary battery according to claim 5, wherein the diameter of the circular hole is smaller at the winding end side of the spiral electrode group than at the winding start side. 7. The method according to claim 5, wherein the number of circular holes is smaller at the winding end side of the spiral electrode group than at the winding start side.
The cylindrical secondary battery as described in the above. 8. The mass of the active material per unit area of the current collector main body is P
And wherein when the mass of the current collector body per unit area is G, the value of G / P is larger at the winding end side of the spirally wound electrode plate group than at the winding start side. 3,
4. The cylindrical secondary battery according to 4, 5, 6, or 7. 9. The positive electrode active material is lead dioxide, the negative electrode active material is lead,
The cylindrical secondary battery according to claim 1, 2, 3, 4, 5, 6, 7, or 8, wherein the current collector is lead or a lead alloy. 10. The positive electrode active material is a composite oxide of lithium and another metal, the positive electrode current collector is aluminum or an aluminum alloy, the negative electrode active material is a carbonaceous material, and the negative electrode current collector is copper or a copper alloy. Claims 1, 2, 3,
4. The cylindrical secondary battery according to 4, 5, 6, 7 or 8.