JP3042027B2 - Sealed lead-acid battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sealed lead-acid battery.

[0002]

2. Description of the Related Art Conventionally, a sealed lead-acid battery is used in any posture and installation direction to prevent the diluted sulfuric acid electrolyte from leaking out of the battery and to maintain the electrochemical contact between the electrode plate and the electrolyte. Therefore, the diluted sulfuric acid electrolyte is substantially non-fluidized. At present, the following two methods can be used to make this electrolyte non-fluidized.
There are different ways.

[0003] One is a method in which an inorganic oxide such as silica is added to an electrolyte to make it gel and become non-fluidized (referred to as a gel-type sealed lead-acid battery). This is a method in which a separator having high liquid retention as a main component is disposed between electrode plates, and an electrolytic solution is impregnated to such an extent that the separator cannot be freely released into the separator (this is referred to as a retainer type sealed lead storage battery). In the case of the gel type, the electrolyte solution can be retained abundantly, but in terms of life, it is impossible to apply a uniform and high pressure to the electrode plate. Therefore, the capacity is deteriorated due to the so-called softening and falling off of the anode plate, and the life is short. On the other hand, in the case of the retainer type, uniform pressure can be applied to the electrode plate group using the flexibility and repulsion of the separator,
It becomes a long-life battery by suppressing softening and falling off, and the retainer type is currently widely used.

[0004] As a separator when the retainer expression, and to hold the electrolyte solution in the separator, the formation layering phenomenon specific gravity difference Ru to put in an electrolytic solution up and down during the cycle as seen in the liquid type battery a maximum pore diameter of separators so as to suppress the vertical movement of <br/> electrolyte by capillary action to prevent had with the existing 8 to 15 m.

[0005]

However, since such a separator having a maximum pore size of 8 to 15 μm is made by using thin glass fibers to reduce the pore size or by increasing the packing density of the glass fibers, electrolytic separators are used. The filling volume that can hold the liquid was limited to 80 to 90%. Therefore, the capacity that can be taken out of the battery is also limited. Further, such a separator is expensive because it uses thin glass fibers with low productivity and requires a large amount of glass fibers . Further, since the separator having a small pore diameter has a low liquid absorption speed, it takes a long time to inject the electrolytic solution into the battery, which causes a problem such as low productivity.

Further, when a battery having this structure is formed in a battery case, there is a problem in contact between the electrode plate and the electrolytic solution due to the low liquid retaining property of the separator, the electrode plate is poorly formed, and the discharge capacity is already formed. It was about 5% lower than the electrode plate.

[0007]

In order to solve the above-mentioned problems, the present invention uses a separator mainly composed of glass fiber having a maximum pore diameter of 15 to 30 μm, and contains silica particles in an electrolyte of 0.5 to 2 μm. It is characterized by being dispersed and gelled by 0% by weight.

[0008]

By dispersing silica in the electrolytic solution, the electrolytic solution gels in the mesh of the separator and the movement of the electrolytic solution above and below the separator is suppressed. This can prevent stratification during the cycle. When silica is added, the maximum pore size of the separator is suitably 15 to 30 μm. If the thickness is less than 15 μm, the movement of the electrolyte becomes too bad, and the discharge capacity decreases. The discharge capacity becomes poor liquid retaining by the hair tubule current <br/> elephants decreases with 30μm or more. The addition amount of silica is suitably 0.5 to 2.0% by weight and 0.5%
Below, the gelation state is poor and the effect of preventing stratification is small. The cycle proceeds in reverse to 2.0% or more by gelation of the electrolytic solution progresses increases the internal resistance of the battery discharge capacity decreases.

The separator having a maximum pore size of 15 to 30 μm can keep the filling density of the glass fiber low, so that the filling volume of the electrolyte can be maintained up to 90 to 96%, and the discharge capacity can be improved. . Furthermore, since it is not necessary to use thin glass fiber as a separator or to increase the packing density, the separator is inexpensive. In addition, since the pore diameter is large, the liquid absorbing speed of the separator is increased, and the injection of the electrolytic solution into the battery is accelerated, so that the productivity can be improved.

[0010] Further, during formation in a battery case, the use of a separator having a high liquid retaining property improves the contact between the electrode plate and the electrolytic solution, and the formation state is the same as that of the formed electrode plate, thereby improving the discharge capacity. can do.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in comparison with a conventional example.
Using three types of glass fiber separators having a maximum pore diameter of 10, 20, and 35 μm, an unpoured battery having an electrode plate height of 230 mm, a width of 140 mm, and a rated capacity of 200 Ah (10 hour rate) was assembled. Injections were made in the combinations shown.

[0012]

[Table 1]

The No. 1 battery took about 2 minutes in the conventional example. Since a large maximum pore size of the separator in batteries Nanba2～8, the liquid suction speed rather fast pouring time is about 1 minute 30
Seconds. Also, the amount of liquid injected could be increased by about 5% as compared with the conventional example. Therefore, the initial capacity was improved by about 5 to 7% in the No. 2 to 8 batteries compared to the No. 1 battery. Maximum hole diameter 3
In No.9 battery of 5 [mu] m, the liquid retaining capacity decreases due to hair tubule current <br/> elephant pore size is too large, the initial capacity was less than the prior art. The same result was obtained with a battery with a smaller capacity than the battery introduced here.

Next, cycle life tests of these batteries were performed. The test conditions were as follows: discharge at 20 A for 5 hours;
The pattern of charging for 6 hours at 0A is defined as one cycle,
The 10 hour rate capacity was measured every cycle. The result is shown in FIG. After the test was completed, the battery of No. 2 had the largest decrease in capacity.
In Example 2, the upper portion was 1.24, the specific gravity difference was 0.08, and the lower portion of the electrode plate was sulphated. No.1,
For 4 to 7 batteries, the specific gravity of the lower part is 1.27 and the specific gravity of the upper part is 1.2.
6, which prevented stratification. In the battery of No. 8 to which 2.5% of silica was added, the electrolytic solution decreased due to the progress of the cycle, the gelation further advanced, the internal resistance of the battery increased, and the discharge capacity decreased.

Although the above-mentioned batteries used electrode plates which had already been formed, the No. 10 battery of the conventional example and the No. 11 battery in which 1.0% silica was added to a separator having a maximum pore diameter of 20 μm were formed in a battery case. Was done. In the No. 11 battery, the silica was not gelled by the agitating action of the electrolytic solution due to gas generation from the electrode plate during the formation, but the gelation proceeded after the formation. Conventional example N
The initial capacity of the o.10 battery was 5% lower than that of the No. 1 battery using the formed electrode plate. Also, the initial capacity of the No. 11 battery was about the same as that of the No. 5 battery using the converted electrode plate having the same configuration, and was 10% or more higher than the No. 10 battery of the conventional example.
Investigation of these batteries revealed that the conventional battery No. 10 had a problem in contact between the electrode plate and the electrolyte solution due to the low liquid retention of the separator, the electrode plate was poorly formed, and the unformed chemical compound lead sulfate was used as the positive electrode. About 8% remained on the board. No. 11 according to the present invention
In a battery, a separator with high liquid retention can be used, so that the contact between the electrode plate and the electrolytic solution is improved. Met.

[0016]

As described in detail above, according to the method of the present invention, the use of a separator having a large maximum pore size and a high liquid retaining property enables the use of a sealed lead-acid battery which is inexpensive, has high productivity, and has a large discharge capacity. It is possible to obtain

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the number of charge / discharge cycles and the discharge capacity in Examples and Comparative Examples of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-136750 (JP, A) JP-A-61-269852 (JP, A) JP-A-3-43954 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01M 2/16

Claims (2)

(57) [Claims] 1. A sealed lead-acid battery having a separator mainly composed of glass fiber and an electrode group consisting of positive and negative electrodes, wherein the separator has a maximum pore size of 15 to 30 μm, and the diluted sulfuric acid electrolyte contains silica. A sealed lead-acid battery in which particles are dispersed and gelled by 0.5 to 2.0% by weight. 2. The sealed lead-acid battery according to claim 1, wherein the formation of the electrode group is performed in a battery case after the group is formed.