JP3433714B2 - Cylindrical lead-acid battery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical lead-acid battery. 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. [0003] Nickel cadmium storage batteries have characteristics such as low internal resistance, high current discharge capability, long cycle life, strong resistance to overcharge and overdischarge, and a wide operating temperature range. Used. Nickel-metal hydride secondary batteries have a high energy density and have been put to practical use mainly in various consumer devices. Further, silver zinc oxide secondary batteries have high output and high energy density, but are expensive, so large ones are mainly used for space and deep sea, while small ones are used for watches and calculators. Widely used for Also,
Lithium-ion batteries are rapidly expanding their applications for consumers due to their advantages such as high operating voltage, high energy density, and no memory effect. [0004] Practical secondary batteries as described above are provided in the form of a prism, a cylinder, a button, a sheet, or the like depending on the application. [0005] As is well known, a cylindrical secondary battery is one in which a thin plate of a positive electrode plate and a negative electrode plate are spirally wound via a separator and housed in a bottomed cylindrical battery container. Demand for various uses is increasing for reasons such as good chargeability. The spiral electrode group is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-185.
As disclosed in Japanese Patent No. 885, a sheet-shaped positive electrode plate 2 and a negative electrode plate are wound around a split-pin-shaped winding shaft 1 via a separator 3, and after winding is completed, this is wound. Made by disengaging from a shaft. This is shown in FIG. Thereafter, the spirally wound electrode plate group is housed in a bottomed cylindrical battery case, and a cylindrical secondary battery is formed through processes such as output terminal formation, lid attachment, and liquid injection. [0007] There is a space corresponding to the winding axis at the center of the spiral electrode group. However, in order to improve the energy density of the cylindrical secondary battery, it is natural. While
Since a smaller space portion in the battery is more preferable, a winding shaft that is as thin as possible is used. For this reason, there is a problem that it takes a considerable time for the electrolyte injected from the liquid inlet formed in the lid of the cylindrical secondary battery to penetrate from the upper part to the lower part of the spiral electrode group. In addition, the spiral electrode group has a problem that the electrolytic solution is less likely to penetrate toward the center since the central portion has a larger fastening stress from the outer peripheral portion. The problem of slow permeation of the electrolyte is particularly serious in a so-called cylindrical lead-acid battery in which the spiral electrode group includes a positive electrode using lead dioxide as an active material and a negative electrode using lead as an active material. Bring. That is, in the cylindrical lead-acid battery, while the injected sulfuric acid electrolyte of a predetermined concentration stays in the upper part of the spiral electrode group for a long time, it reacts with the unformed active material on the upper part of the spiral electrode group to form sulfuric acid. This is because only a thinner sulfuric acid electrolytic solution permeates into the lower part of the spiral electrode group, causing internal short circuit failure. As means for solving the above problems, as disclosed in Japanese Patent Application Laid-Open No. Sho 64-77881, a dam is formed by projecting a part of a separator, and an electrolyte is stored therein. It has been proposed to promote the penetration of the electrolyte in the center by doing so, but in order to achieve this, the width of a part of the long separator must be increased,
There is a problem that it is not practical in terms of production efficiency (see FIG. 3). SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a cylindrical lead-acid battery capable of smoothly permeating an electrolytic solution and being practical in terms of production efficiency. That is. According to a first aspect of the present invention, there is provided a cylindrical lead-acid battery having a spirally wound electrode group housed in a cylindrical container, wherein the outer diameter of the spirally wound electrode group is R. And r / R is 0.09 or more, where r is the inner diameter of the central space. DETAILED DESCRIPTION OF THE INVENTION The present invention has been made based on the recognition of how to increase the permeation rate of an electrolytic solution and to provide a low-cost cylindrical lead-acid battery with less performance defects. By setting the size of the central space of the spiral electrode group to a predetermined value with respect to the outer dimensions of the spiral electrode group, without deteriorating performance or production,
It was completed after finding things that could be improved. An embodiment of a cylindrical lead-acid battery having a nominal capacity of 10 Ah will be described below. First, an electrode plate substrate having a width of 80 mm and a length of 500 mm was punched out from a lead alloy foil having a thickness of 0.6 mm. Next, an electrode was manufactured using the electrode plate base. The positive electrode has an oxidation degree of 70% (metal lead 30%, lead monoxide 7
(0%) lead powder and dilute sulfuric acid were kneaded to obtain an active material paste, which was then applied to both surfaces of the electrode substrate. The theoretical capacity of the positive electrode is about 26 Ah. In the negative electrode, an active material paste is obtained by adding a slight amount of carbon powder, a barium compound and lignin to lead powder having an oxidation degree of 70% (metal lead 30%, lead monoxide 70%) and kneading dilute sulfuric acid. After that, these were applied to both surfaces of the electrode plate substrate. The theoretical capacity of the negative electrode is 28 Ah. The positive electrode 2 and the negative electrode 3 are wound through a glass mat separator 4 to form a spiral electrode group 5.
I got This is shown in FIG. Reference numeral 6a denotes an electrode plate ear formed on the positive electrode 2;
“a” denotes electrode lugs formed on the negative electrode 3, which are arranged on one end face of the spiral electrode group 5. Reference numeral 8 denotes a central space of the spirally wound electrode group, where the winding shaft is inserted at the time of winding. In order to examine how the size of the central space 8 affects the permeation rate of the electrolyte and the performance of the battery, the thickness of the winding shaft is changed when the spiral electrode group is formed. In this way, a spiral electrode group was manufactured. Table 1 shows the results of the measured values of the outer diameter of the spiral electrode group and the inner diameter of the central space (average value of 10 pieces) under each condition. In Table 1, the units of r and R are mm, and the measurement points are 4 for one sample.
The average value of each of 10 samples is shown (see FIG. 4). [Table 1] After forming a strap and an output terminal (a so-called pole) on these electrode plates by the COS method, the inner diameter is 45 m.
An m-cylindrical polyolefin resin container was placed in the battery case, and a lid of the same material was adhered by ultrasonic welding to obtain an uninjected cylindrical lead-acid battery having an outer diameter of 50 mm and a height of 115 mm (excluding the output terminal). These unfilled cylindrical lead-acid batteries have a specific gravity of 1.
A 30 (at 20 ° C.) sulfuric acid electrolyte solution was injected into each 60 CCC, and the permeation time was measured. Table 2 shows the results. In Table 2, the average permeation time of the sample (a) is represented as 100. [Table 2] From the results shown in Table 2, it was found that when the value of r / R was 0.09 or more, the permeation rate of the electrolytic solution was significantly increased. Next, these batteries were subjected to battery formation at a constant current of 0.25 CA for 40 hours, and then discharged at 1 CA (1.7 times).
V termination) 1CA constant current x 2.45V constant voltage charging (1.
(5 hours). At the end of 50 cycles, (a) and (b)
Internal short circuits occurred one by one, but others were good. The reason for the occurrence of the early internal short circuit between (a) and (b) is presumed to be as follows. In other words, when the electrolyte is injected into the unleaded cylindrical lead-acid battery, it takes time for the electrolyte to penetrate, and while the electrolyte remains at the upper part for a long time, the non-activation of the upper part of the spiral electrode group is performed. Sulfuric acid was consumed by reacting with the substance, and only a thinner sulfuric acid electrolyte permeated below the spiral electrode group. For this reason, a minute short-circuit occurred at the lower part of the spiral electrode group during the formation of the battery case, and it progressed with an increase in the number of cycles. With respect to the discharge capacity in the first cycle, no remarkable difference was observed between (a) to (f). In the above example, the width is 80 mm × length 500 mm
The same result was obtained even when the width and length of the electrode plate were larger, so that the end face of the spiral electrode group was reduced by the permeation speed of the electrolytic solution. It is presumed that the size (apparent area) is related to the size of the hole in the central space. According to the present invention, there is provided a cylindrical lead-acid battery excellent in liquid injection performance and battery performance without causing disadvantages in performance and production efficiency.

[Brief description of the drawings] FIG. 1 is a diagram showing a method for manufacturing a spiral electrode group. FIG. 2 is a diagram illustrating a spiral electrode group. FIG. 3 is a diagram showing a conventional example. FIG. 4 is a diagram showing a spiral electrode group; [Explanation of symbols] 5 Spiral electrode group 8 Central space of spiral electrode group

Claims (1)

(57) [Claim 1] In a cylindrical lead-acid battery in which a spiral electrode group is housed in a cylindrical container, the outer diameter of the spiral electrode group is R, and When the inner diameter is r, r / R is 0.0
9. A cylindrical lead-acid battery characterized by having 9 or more.