JPS61267274A - Enclosed lead storage battery - Google Patents

Abstract

PURPOSE:To easily obtain an enclosed lead storage battery, in which an electrolyte is uniformly present, by providing the electrolyte containing silicon dioxide and a sulfate, and by causing the electrolyte to gel over the entire range of a separator. CONSTITUTION:An electrode group, in which a positive and a negative electrode plates are stacked with an interposed separator, is housed in a battery jar. An electrolyte containing 1-4wt% of silicon dioxide and 0.5-5wt% of a sulfate is provided so that the electrolyte is in a state of gel over the entire range of the separator. Since the electrolyte is in the state of gel over the entire range of the separator, the electrolyte does not become nonuniformly present during the operation of the battery. Therefore, the life of the battery is long. Since the silicon dioxide is negatively charged, it does not happen that only the liquid portion of the electrolyte is preferentially absorbed by the negatively- charged separator. Since the grain diameter of the silicon dioxide is as small as 10-20mmu, it is not hindered by the separator.

Description

[Detailed Description of the Invention] The present invention is applicable not only to conventional small sealed lead-acid batteries such as emergency power supplies and portable equipment power supplies, but also to larger stationary batteries, automotive batteries, etc. The purpose of this invention is to provide a sealed lead-acid battery that can also be used for electric vehicles.

Conventional □Last 91 Questions and Answers 11 Answers 1 point The conventional liquid fixing method for sealed lead-acid batteries involves applying a liquid electrolyte to a fine glass mat separator made of fine glass fibers with an average fiber diameter of about 1 μm. There are a micro glass cloak method in which the capacitor is held, a gel method that uses a gel-like electrolyte, and a combined method that uses a separator and a gel-like electrolyte to take advantage of these advantages.

However, in this combination method, there is a problem in that it is extremely difficult to control the proportion of silicon dioxide and the amount of electrolyte injected in order to ensure fluidity during injection of the electrolyte and to form a gel after injection. there were.

For this reason, for example, as shown in JP-A-56-123675, a proposal has been made to gel only the electrolyte around the electrode group, but with this method, the electrolyte becomes noticeably unevenly distributed during battery operation. Therefore, it has the disadvantage of short life.

The present invention relates to closed lead-acid batteries and aims to provide a battery that is easy to manufacture and has a long life.

In other words, the present invention is characterized in that in a sealed lead-acid battery that uses a liquid-absorbing separator and a gelled electrolyte, a positive electrode plate and a negative electrode plate are laminated with the separator interposed therebetween. The formed electrode group is housed in a battery case, and has an electrolytic solution containing 1 to 4% by weight of silicon dioxide and 0.5 to 5% by weight of sulfate, and the electrolytic solution forms a gel over the entire area of the separator. It is characterized by being

real scream The present invention will be explained below with reference to one embodiment thereof.

That is, before assembly, two positive electrode plates and three negative electrode plates, which had sulfuric acid groups in advance, were stacked together via a fine glass mat separator made of fine glass fibers with an average fiber diameter of about 1 μm to form an electrode group ( η] The size of this positive electrode plate and negative electrode plate is 450 m in height, respectively.
m, medium 140mm, thickness 4mm, and height 450mm
, 140 mm inside and 3 mm thick. After storing this electrode group in a container, silicon dioxide (SiO2 with a particle size of 10 to 20 mμ) was added to dilute sulfuric acid with a specific gravity of 1.220 to 1.280.
2% by weight and 5g of sulfate salt (Na2SOa)
/β is dispersed in an electrolytic solution of 5 to 15% from the polar group space volume.
% more liquid was injected, and the battery was allowed to stand still to allow the electrolyte to gel over the entire area of the separator. That is, it is thought that the addition of this sulfate disrupts the ionic balance of negatively charged silicon dioxide in the electrolytic solution, thereby causing gelation over the entire area of the separator. Thereafter, a top cover with a valve was attached to the battery case and the battery was charged, completing a sealed lead-acid battery according to the present invention.

JP-A-56-123675 discloses the sealed lead-acid battery a according to the present invention as described above, and the same electrode plate, using a fine glass mat as a separator, and gelling only the electrolyte around the electrode group. The following cycle life characteristics test was conducted using a sealed lead-acid battery as shown in the figure below. In other words, when the discharge depth is 50%, the discharge amount is 1
Alternate charging and discharging was performed by repeating 20% charging, and a capacity test with a discharge current of 5 A was inserted as appropriate during the alternating charging and discharging, and the discharge duration was measured. The results are shown in FIG.

Note that the test temperature at this time was 25° C., and the final voltage of the discharge duration was 1t80V.

From FIG. 1, it can be seen that the sealed lead-acid battery a according to the present invention has superior life performance compared to the sealed lead-acid battery. This is thought to be because the electrolyte solution is not unevenly distributed even inside. In other words, according to the present invention, by using negatively charged silicon dioxide, only the liquid part of the electrolyte is not preferentially absorbed by the negatively charged separator, and the particle size of silicon dioxide also increases. 10
Since it is small at ~20 mμ, it is not obstructed by the separator. As described above, according to the present invention, silicon dioxide is uniformly distributed inside the electrode group, and is then gelled by the gelling action of the sulfate.

In the present invention, silicon dioxide is suitably contained in an amount of 1 to 4% by weight based on the electrolytic solution. That is, if it is less than 1% by weight, the gelation effect will be small, while if it exceeds 4% by weight, gelation will be rapid and the injection workability will be poor.

Furthermore, in the present invention, in addition to its role as a gelling aid, the sulfate seems to contribute to longer life by suppressing the dissolution of lead ions from the electrode plate during cycle use.

The appropriate amount is 0.5 to 5% by weight based on the electrolyte. That is, if it is less than 0.5% by weight, the effect will be small, and if it exceeds 5% by weight, the effect will not change, and in some cases it may have an adverse effect on the battery.

In the above embodiments, the present invention was applied to a paste-type sealed lead-acid battery, but the present invention is not limited to this and can also be applied to a clad-type sealed lead-acid battery.

Further, in the present invention, the separator may be liquid-absorbing, but it is more preferable to use a separator with high porosity such as the fine glass mat separator shown in the examples.

As described above, according to the present invention, it is possible to easily obtain a sealed lead-acid battery in which the electrolytic solution uniformly gels over the separate lakes, and the electrolytic solution is not unevenly distributed.

Second, the present invention can provide a sealed lead-acid battery with excellent life performance, and has extremely high industrial value.

[Brief explanation of the drawing]

FIG. 1 shows a sealed lead-acid battery a in an embodiment of the present invention.
2 is a graph showing cycle life characteristics when a sealed lead-acid battery not according to the present invention was tested.

Claims (1)

[Claims] In a sealed lead-acid battery using a liquid-absorbing separator and a gelled electrolyte, an electrode group formed by laminating a positive electrode plate and a negative electrode plate with the separator interposed in between is housed in a battery case, and A sealed lead acid battery comprising an electrolytic solution containing 4% by weight of silicon dioxide and 0.5 to 5% by weight of sulfate, the electrolytic solution being gelled throughout the separator.