JPS61250968A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To increase life and reduce cost by using a mat made of ceramic fibers having a specified composition ratio of silica and alumina and a specified average diameter in a separator. CONSTITUTION:An electrode group is obtained by stacking two positive plates nd three negative plates both previously impregnated with sulfuric acid with separators interposed between them. A mat made of ceramic fibers whose total composition ratio of silica and alumina is 90% or more and whose average diameter is 40mum or less is used as the separator. The electrode group is accommodated into a container, and electrolyte obtained by dispersing a specified weight ratio of silicon dioxide into dilute sulfuric acid having a specified specific gravity is poured into the container and a battery is allowed to stand to gel the electrolyte..The cost of the separtor is reduced, and by using this separator and gelled electrolyte, the life of the sealed lead-acid battery is increased.

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 power sources for voltaple equipment, but also to larger stationary batteries and automobiles. The purpose of the present invention is to provide a sealed lead-acid battery that can also be used for electric vehicles.

Conventional liquid fixing methods for sealed lead-acid batteries include a fine glass mat method in which a liquid electrolyte is held in a fine glass mat separator made of fine glass fibers with an average fiber diameter of about 1μ; There is a gel method that uses a gel electrolyte solution, and a combination method that uses a separator and a gel electrolyte solution to take advantage of these advantages.

In addition, as the combination method, there are a method using a fine glass mat as the separator, and a method using a separator such as a sintered PvC or a paper separator used in a so-called flowing electrolyte type lead-acid battery.

However, among this combination method, the one using a fine glass mat had the disadvantage that the fine glass cloak was expensive and its field of use was limited. In those using separators used in electrolyte type lead acid batteries, the separator has a high density and a low porosity of about 60%, so there is a problem that the amount of electrolyte retained is small and the battery capacity is inferior. Furthermore, since the separator has poor elasticity, it lacks active material retention and has a short lifespan.

In view of the above points, the present invention was made with the aim of providing a sealed lead-acid battery that uses a liquid-absorbing separator and a gelled electrolyte at low cost and long life. .

In other words, the present invention is characterized in that the separator uses a mat made of ceramic fibers having a composition in which the total proportion of silica and alumina is 90% or more and has an average fiber diameter of 4.0μ or less. It is in the fact that

On the actual plate The present invention will be explained below with reference to one embodiment thereof.

In other words, two positive electrode plates and three negative electrode plates, which have sulfuric acid groups in advance before assembly, have a composition in which silica (Si02) accounts for 52%, alumina (A 1203 ) accounts for 47%, and 285μ A pole group was obtained by stacking mats made of ceramic fibers with an average fiber diameter of 1 through a separator. The size of this positive electrode plate and negative electrode plate is 450 mm in height and 140 mm in width, respectively.
, thickness 4IIlff11 and height 450mo+, medium 1
It was 40 am and 3III+ thick. After storing this electrode group in a battery container, an electrolytic solution in which 3% by weight of silicon dioxide is dispersed in dilute sulfuric acid with a specific gravity of 1.220 to 1.280 is injected in an amount of 5 to 15% more than the space volume of the electrode group. The battery was allowed to stand still to allow the electrolyte to gel.

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.

Sealed lead-acid battery a according to the present invention as described above, and conventional sealed lead-acid battery b that uses the same electrode plate and uses a fine glass mat as a separator and a gel electrolyte, and also uses the same electrode plate. A conventional sealed lead-acid battery C using sintered PVC as a separator and a gel electrolyte was used to conduct the following cycle life characteristic test. In other words, alternate charging and discharging is performed by repeating discharging at a depth of discharge of 50% and charging at 120% of the amount of discharge, and during this alternate charging and discharging, a capacity test with a discharge current of 5 A is inserted as appropriate to determine the duration of the discharge. It was measured. The results are shown in FIG. The test temperature at this time was 25°C,
Further, the final voltage of the discharge duration was set to 1.80V.

Figure 1 shows that the sealed lead-acid battery a using the separator of the present invention has a price ratio of the separator compared to the conventional sealed lead-acid battery that uses a fine glass cape as a separator and a gel electrolyte. Although it is much cheaper at about 20%, its performance is almost comparable.

The possible reasons for this are as follows. In other words, the ceramic fibers used as separators in sealed lead-acid batteries a have an average fiber diameter of about 2 to 4 μm, which is thicker than the 1 μm or less diameter of fine glass mats, but when combined with a gel-like electrolyte, This is thought to be because they have essentially the same function. In addition, cheap ceramic fibers contain shot (non-fibrous particles), but these particles have a larger particle size than the silicon dioxide used to gel dilute sulfuric acid, so silicon dioxide This prevents the silica skeleton structure formed from becoming too dense, which has favorable results for battery performance.

This is because if this skeletal structure becomes too dense,
This is because it becomes difficult to secure a passage for gas movement, and it also becomes difficult to move the electrolyte, which adversely affects the capacity performance and life performance of the battery. Furthermore, ceramic fiber contains CaO1Mg01B203 and N contained in glass fiber.
It does not contain metal oxides such as a20, is stable against acids, and is thought to be uniformly gelatinous and inexpensive.

Although the present invention was applied to a paste-type sealed lead-acid battery in the first embodiment, the present invention is not limited thereto, and can also be applied to a clad-type sealed lead-acid battery.

It is also possible to use organic or inorganic binders when processing ceramic fibers into plate shapes to make separators, but in order to have excellent elasticity and high porosity, it is preferable not to use these. .

As described above, the separator of the present invention is inexpensive,
By applying this to a sealed lead-acid battery that uses a gelled electrolyte, an excellent battery can be provided.

As mentioned above, the present invention has extremely great industrial value.

[Brief explanation of drawings]

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

Claims (1)

[Claims] In a sealed lead-acid battery that uses a liquid-absorbing separator and a gelled electrolyte, the separator has a composition in which the total proportion of silica and alumina is 90% or more, and 4.0
A sealed lead-acid battery characterized by using a mat made of ceramic fibers having an average fiber diameter of μ or less.