JP3511858B2 - Lead storage battery - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Negative electrode absorption type sealed lead acid battery in which most of electrolytic solution is impregnated in positive and negative electrode plates and a mat-shaped separator mainly made of glass fiber has low self-discharge and excellent maintainability. It has features such as being present and is used for various purposes. In recent years, sealed lead-acid batteries have begun to be used also for relatively large automobile batteries, and there is a great demand for high rate discharge performance particularly at low temperatures in these automobile batteries.

However, in the case of a sealed lead storage battery, when it is made large like an automobile battery, the electrolyte solution is not sufficiently impregnated in the upper part of the electrode plate group, resulting in high resistance and poor high rate discharge performance at low temperatures. There is. In order to solve this, conventionally, as disclosed in JP-A-62-122076, the lower part of an electrode plate group in which a hydrophilic porous separator having a smaller liquid holding capacity than an active material is closely attached to a positive and negative electrode plates is used as an electrolytic solution. Means such as using an electrode plate having a structure in which the active material is continuous in the vertical direction while being immersed is known.

[0004]

In the case of the battery of this structure, the problem that the sulfuric acid in the electrolytic solution necessary for high rate discharge is difficult to be supplied from the separator to the electrode plate due to the small liquid holding capacity of the separator. there were. Further, when a mat-shaped separator mainly made of glass fiber was used, the resistance was high because the electrolyte holding amount was different between the upper and lower electrode plate groups as described above.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a sealed lead-acid battery having a high rate discharge performance at a low temperature and an excellent recovery property after being left over-discharged.

[0006]

In order to achieve the above object, the present invention forms an electrode plate group by using an electrode plate on the surface of which paste paper mainly composed of pulp fibers is applied, and the electrode plate group is formed. The lower part is soaked in the electrolytic solution.

In the sealed lead-acid battery of the present invention, a positive electrode plate or a negative electrode plate is provided with an electrode plate having a paste paper mainly composed of pulp fibers on its surface, and a mat-shaped separator mainly made of glass fibers is closely adhered to them. This is a configuration in which the lower part of the electrode plate group thus prepared is immersed in an electrolytic solution. The pulp fibers that make up the paste paper have high liquid retention by changing to a paste form due to the presence of dilute sulfuric acid in the electrolytic solution, and since the paste paper intervenes between the electrode plate and the separator so as to adhere closely, The supply of the electrolytic solution to the electrode plate can be improved.

[0008] Generally, paste paper is obtained by a manufacturing method in which a mixed solution in which pulp fibers are dispersed as a main component is made into a sheet by a cylindrical net, pulled up, and then molded and dried. Although the role of the paste paper in the present invention is to secure the wettability between the electrode plate and the separator, since the paste paper itself is a thick one because it becomes an electrical resistance, the high rate discharge performance decreases, In order to obtain the effect, the actual thickness is 0.1 mm or less.

[0009]

FIG. 1 shows a cross section of a negative electrode absorption type sealed lead-acid battery according to an embodiment of the present invention. An expanding positive electrode plate 1 and a negative electrode plate 2 are used for this, and the dimensions are 137 mm in width and 114.5 mm in height. The pasted paste paper 3 is attached to both the front and back surfaces of the expanded electrode plate, and the average fiber length of the constituent is about 10 m.
m, the thickness is about 0.05 so as not to affect the high rate discharge characteristics.
mm, and the basis weight was 15 g / mm 2. The mat-shaped separator 4 is mainly composed of glass fibers 4. A plurality of these electrode plates and separators are alternately stacked and closely adhered to each other to form an electrode plate group of 5 positive electrode plates and 6 negative electrode plates, and the battery case 5
30 mm in the lower part of the electrode plate group is immersed in the electrolytic solution 6 which is dilute sulfuric acid in the state of being housed in. Pressure is applied to the electrode plate group by a battery case rib 7, a lid 8 is welded to the upper part of the battery case 5, an exhaust pipe 9 is present at the center thereof, and a cap-shaped rubber valve is provided at the tip thereof. A safety valve 10 is installed.

[0010]

[Embodiment] 12V48 of the present embodiment configured as described above
A sealed lead acid battery A of Ah was prepared. Further, a similar sealed lead-acid battery B in which the paste sheet is removed from the configuration of the battery A and the lower portion of the electrode plate group is immersed, and a battery in which there is no fluid electrolyte in which the lower portion of the electrode plate group is immersed from the configuration of the battery A C,
Further, a battery D was prepared by removing the paste paper and the flowable electrolytic solution in which the lower 30 mm of the electrode plate group was immersed from the configuration of the battery A. Battery A is an embodiment of the present invention,
Batteries B, C and D are conventional examples.

Regarding the above four types of batteries, JISD
5301 high rate discharge characteristics (300A discharge at -15 ° C)
In addition, the results of investigating the recoverability after leaving for over-discharge are shown in (Table 1).

[0012]

[Table 1]

Regarding the high rate discharge characteristics, in comparison with the structure of the battery D, the battery B in which the lower part of the electrode plate group is immersed in the electrolytic solution is
10% better in duration than Battery D, and Battery C to which paste paper was applied was found to have an improvement of 7% in duration as compared to Battery D. However, it was found that the battery A, which is an embodiment of the present invention having a configuration in which the battery B and the battery C are combined, has a 25% improvement in duration compared to the battery D. Had better properties than. This is the battery A of this embodiment.
Since the lower part of the electrode plate group is immersed in the electrolytic solution, sufficient electrolytic solution is secured in the upper part of the electrode plate group, and the electrolytic solution is absorbed by the paste paper and the wettability between the electrode plate and the separator. Since it is easy to supply sulfuric acid from the separator to the electrode plate, the utilization rate of the active material is improved and excellent high rate discharge performance is obtained.

On the other hand, the recoverability after being left over discharge is the ratio of the discharge capacity after that to the discharge capacity before being left over discharge. In general, lead-acid batteries have the property that the discharge characteristics deteriorate when left to over-discharge, and this is because sulfuric acid in the electrolyte solution is consumed and the electrolyte solution in the vicinity of the positive electrode grid is in the alkaline region. This is because a corrosion layer having a high electric resistance is generated at the interface of. As shown in Table 1, the battery A, which is an example of the present invention, had excellent recoverability after over-discharging, as compared with the batteries B, C, and D of the conventional example. This is because the battery A can easily supply sulfuric acid from the separator to the electrode plate as described above.
It is considered that this is because the electrolytic solution in the vicinity of the positive electrode grid is unlikely to be alkaline.

Further, in the constitution of the present invention, the discharge performance and oxygen gas absorption capacity of the battery vary depending on the liquid holding capacity of the mat-shaped separator, but the present invention can be used even if a separator having a small liquid holding capacity is used. The effect of the above was similarly recognized. Therefore, according to the present invention, it is possible to improve the high rate discharge performance while maintaining the gas absorption capacity having the maintenance-free property of suppressing the liquid reduction during use.

In the above embodiment, the electrode plate provided with the paste paper was used for both the positive and negative electrodes, but the same effect can be obtained by using either one of the electrode plates.

Further, in general, an expanded electrode plate used in a lead storage battery is prepared by expanding a lead or lead alloy sheet at the time of its manufacture and filling a grid-like grid body with a paste-like active material. Paste paper is applied on both sides. Although the expanded electrode plate is used in the above-mentioned embodiment, the present invention can be embodied by applying the paste paper to both the front and back surfaces of the electrode plate even if the electrode plate is filled with the active material in the casting type grid. The same effect can be obtained.

[0018]

As described above, according to the present invention, even in the case of a large sealed lead-acid battery such as a battery for automobiles, it is possible to eliminate the high resistance due to the shortage of the electrolytic solution in the upper part of the electrode plate group, It is possible to realize a sealed lead-acid battery that has excellent rate discharge performance and recovery after being left over-discharged.

[Brief description of drawings]

FIG. 1 is a sectional view of a negative electrode absorption type sealed lead-acid battery according to the present invention.

[Explanation of symbols]

1 Positive plate 2 Negative electrode plate 3 paste paper 4 Matte separator 5 battery case 6 Electrolyte 7 ribs 8 lid 9 Exhaust stack 10 safety valve

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-8-78014 (JP, A) JP-A-62-122076 (JP, A) JP-A-60-140676 (JP, A) JP-A-57- 15359 (JP, A) JP-A-64-19674 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 10/06 H01M 10/12 H01M 4/14 H01M 4/74

Claims (3)

(57) [Claims] 1. A structure in which a lower part of an electrode plate group consisting of a positive electrode plate, a negative electrode plate, and a separator having a liquid retaining capacity is immersed in an electrolytic solution, and pulp fibers are mainly formed on the surface of the electrode plate. A sealed lead acid battery characterized by having paste paper. 2. The sealed lead acid battery according to claim 1, wherein an electrode plate having a paste paper on its surface is used for the positive electrode and the negative electrode. 3. The sealed lead-acid battery according to claim 1, wherein the grid body used for the electrode plate is an expanded grid.