JPH11126630A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish great improvement of a liquid reduction characteristic in a hybrid battery and in a conventional battery and further improvement of that in a calcium battery by covering a group of electrodes by means of an oxygen gas-impermeable film passing no foaming oxygen gas. SOLUTION: In a lead-acid battery, for discomposing and dissolving oxygen gas in an electrolyte, an oxygen gas-impermeable film 2, which prevents oxygen gas generated from an electrode in a group of electrodes 1 from passing through so as to sufficiently diffuse the oxygen gas inside the group of electrodes 1, is put on almost the whole of the group of electrodes 1 excepting the lower ends in their installed condition. As the group of electrodes 1 is covered by means of the oxygen gas-impermeable film 2 in this way, oxygen gas generated in a charging time so as to be diffused inside the group of electrodes 1 can be held by means of the oxygen gas-impermeable film 2. Moreover, convection current can be generated when the oxygen gas collides against the oxygen gas-impermeable film 2. Therefore, the oxygen gas can be sufficiently diffused and dissolved in the electrolyte, and a part of the oxygen gas is absorbed on a negative electrode surface so that reduction of the solution can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-acid battery in which an electrode group is accommodated in a battery case.

[0002]

2. Description of the Related Art At present, a battery using a Pb-Ca alloy lattice for a negative electrode plate and a Pb-Sb alloy lattice for a positive electrode plate (hereinafter, referred to as a battery).
Abbreviated as hybrid battery. ), P on the negative and positive plates
There are batteries using a b-Ca alloy lattice (hereinafter abbreviated as calcium batteries) and batteries using a Pb-Sb alloy lattice for a negative electrode plate and a positive electrode plate (hereinafter abbreviated as conventional batteries).

[0003] Hybrid batteries and conventional batteries use a Pb-Sb alloy grid as the positive grid, so that the active material of the positive electrode is prevented from sulfation by the effect of antimony, and is resistant to deep discharge and overdischarge. is there.

Since the calcium battery uses a Pb—Ca alloy lattice for the positive electrode plate, antimony elutes and the hydrogen overvoltage of the negative electrode plate does not decrease due to electrodeposition on the negative electrode plate. And a battery with a small decrease in electrolyte.

[0005]

However, in the hybrid battery and the conventional battery, since Sb having a low hydrogen overvoltage is added to the positive electrode lattice alloy, antimony elutes and precipitates on the surface of the negative electrode plate, and hydrogen is added. There are problems of remarkable generation of gas, decrease of electrolyte solution, and self-discharge.

On the other hand, in a calcium battery, S
Since the b-alloy grid is not used, there is a problem that the sulfation of the positive electrode active material is remarkable, and it is weak to leave in deep discharge and over-discharge, and there is a problem that the positive grid expands and short-circuits when used at a high temperature. .

Further, in recent years, all batteries have a common point that the environment of the battery becomes high temperature due to the increase in the number of electric components of the automobile and the overcrowding in the hood due to the change of the specification of the automobile, and the reduction of the electrolyte is promoted. Has become a serious problem.

An object of the present invention is to provide a lead-acid battery that can greatly improve the liquid reduction characteristics of a hybrid battery and a conventional battery, and can further improve the liquid reduction characteristics of a calcium battery.

[0009]

SUMMARY OF THE INVENTION The present invention is to improve a lead-acid battery in which an electrode group formed by alternately stacking a negative electrode plate and a positive electrode plate via a separator is accommodated in a battery case.

[0010] In the lead storage battery of the present invention, the electrode group is covered with an oxygen gas impermeable film through which oxygen gas in a bubble state does not pass. The oxygen gas impermeable membrane may cover substantially the entire electrode group except the lower end in the installed state, or may cover only the upper part in the installed state.

In the present invention, the upper part in the installed state is defined as an installed state (a vertically installed state in which the strap is directed upward, or a horizontal installed state in which the plate surface of the electrode plate is oriented vertically and the strap is oriented horizontally. And the upper end surface of the electrode plate group and the upper peripheral surface of the electrode plate group extending from the upper end surface of the electrode plate group. There are cases.

The oxygen gas impermeable membrane sufficiently disperses and dissolves the oxygen gas generated from the positive electrode plate during charging in the electrolytic solution, and causes a part of the oxygen gas to undergo a gas absorption reaction on the surface of the negative electrode plate. Is to suppress the decrease in

Conventionally, there have been known methods of leveling the ribs of a battery case for the purpose of better stirring the electrolytic solution, and floating plastic beads for the purpose of suppressing the evaporation of the electrolytic solution. These methods are also known. It is presumed that this is effective in dispersing and dissolving oxygen gas, but it is known that practically no effect is obtained. The reason is considered to be that oxygen gas dispersed in the electrode group cannot be sufficiently held.

Hereinafter, the operation of the present invention will be described in detail.

By diffusing oxygen gas generated from the positive electrode plate into the electrolytic solution, the oxygen gas moves to the surface of the negative electrode plate, and Pb of the negative electrode plate is oxidized by the oxygen gas as shown in equation (1). Is thought to occur. As a result, oxygen gas generated during overcharging can be absorbed, and the amount of liquid reduction can be reduced. Further, in the hybrid battery and the conventional battery, antimony precipitates on the surface of the negative electrode plate, and a potential difference from lead is locally generated, so that a self-discharge reaction occurs. In the negative electrode plate, hydrogen is generated by a self-discharge reaction as in the equation (2), and the amount of electrolyte decreases.

However, in the present invention, the presence of the oxygen gas impermeable film covering the electrode group allows the oxygen gas generated during charging and dispersed in the electrode group to be held by the oxygen gas impermeable film. This oxygen gas is sufficiently dispersed and dissolved in the electrolytic solution, and the reaction of the formula (1) precedes, and a decrease in the electrolytic solution due to self-discharge can be suppressed.

[0017]

Embedded image In particular, when the entirety of the electrode group except the lower end is covered with the oxygen gas impermeable film in the installed state, the oxygen gas dispersed in the electrode group is more dispersed than the one that covers only the upper part in the installed state. It can be held sufficiently.

[0018]

1 and 2 show a first example and a second example of an embodiment of a lead-acid battery according to the present invention.

In the lead-acid battery of this embodiment, in order to disperse and dissolve oxygen gas in the electrolyte, as shown in FIGS.
An oxygen gas-impermeable membrane 2 capable of sufficiently dispersing oxygen gas in the electrode plate group 1 without permitting oxygen gas generated from the electrode plates of the electrode plate group 1 to pass therethrough is provided with an electrode in which the lower end is removed in an installed state. It covers almost the entire plate group 1 (FIG. 1), or covers only the upper part in the installation state of the electrode group 1 (FIG. 2).

As shown in FIG. 1, in a vertically installed state, covering substantially the entirety of the electrode plate group 1 except for the lower end with the oxygen gas impermeable film 2 means that the electrode plate ears 3 of the same polarity are covered. The upper end surface of the electrode group 1 on which the connected straps 4 are present (upward stacking surface of the electrode plates) and the entire peripheral surface of the electrode group 1 connected to the upper end surface are covered with the oxygen gas impermeable film 2. It is. In this case, it is better to cover between the lugs 3 where the polar tab lugs 3 of the same polarity are adjacently arranged with the oxygen gas impermeable membrane 2. Can be obtained.

In the case of the horizontal installation state, almost the entire electrode group 1 is covered by the upper end surface (upwardly stacked electrode plate surface) of the electrode group 1 in the horizontal installation state and the upper end surface. The entire peripheral surface of the electrode group 1 is covered with the oxygen gas impermeable film 2 as in the case of the vertically installed state.

As shown in FIG. 2, in a vertically installed state, covering only the upper portion of the electrode plate group 1 with the oxygen gas impermeable film 2 means connecting the electrode plate ears 3 of the same polarity. The upper end surface of the electrode group 1 on which the straps 4 are present (upwardly stacked electrode plate surface) and the upper peripheral surface of the electrode group 1 connected to the upper end surface are covered with the oxygen gas impermeable film 2. is there. Again,
It is better to cover the space between the ears 3 where the pole ears 3 of the same polarity are arranged adjacently with the oxygen gas impermeable membrane 2. Can be.

In the horizontal installation state, only the upper part of the electrode group 1 is covered by the electrode group 1 in the horizontal state.
And the upper peripheral surface of the electrode plate group 1 connected to the upper end surface is covered with the oxygen gas impermeable film 2 in the same manner as in the vertically installed state. .

Such an electrode plate group 1 is housed in a battery case together with an electrolytic solution, not shown, to constitute a lead storage battery.

As described above, the electrode group 1 is provided with the oxygen gas impermeable film 2.
, Oxygen gas generated at the time of charging and dispersed in the electrode plate group 1 can be held by the oxygen gas impermeable film 2, and the oxygen gas impinges on the oxygen gas impermeable film 2. Convection can be caused, and oxygen gas can be sufficiently dispersed and dissolved in the electrode plate group 1. In this case, the positive electrode plate is sandwiched between the negative electrode plates,
Oxygen gas generated from the positive electrode plate rises through the space between the positive electrode plate and the adjacent negative electrode plate, but in the present invention, the oxygen gas impermeable film 2 prevents the gas from going out of the electrode plate group 1, and the above-described phenomenon occurs. Will occur.

The oxygen gas impermeable membrane 2 is preferably an insulator having corrosion resistance to sulfuric acid and high temperature resistance, and various synthetic resins are suitable. For example, polyethylene, polypropylene, polystyrene, polyvinyl chloride,
A synthetic resin such as polyester can be used. Since the oxygen gas impermeable membrane 2 formed of these synthetic resins does not transmit oxygen gas, the dispersion state of oxygen gas is the same, and oxygen gas is dispersed and dissolved in the electrode plate group 1 to form a negative electrode plate. The effect of absorption on the surface is the same.

[0027]

EXAMPLES Examples 1 and 2 of a lead storage battery according to the present invention were performed to confirm the effects of the lead storage battery according to the present invention.
And the results of comparative experiments with the lead storage batteries of Comparative Examples 1 to 4 will be described below.

The lead storage batteries of Examples 1 and 2 and Comparative Examples 1 to 4 were manufactured as follows.

(Comparative Example 1) Using a Pb-Ca alloy lattice,
An electrode group was formed by laminating six unformed negative electrode plates covered with a bag-shaped polyethylene separator and five unformed positive electrode plates using a Pb-Sb alloy lattice.

After the electrode group was placed in a battery case, an electrolytic solution was injected into the battery case to produce an unformed battery.

Next, this unformed battery was formed at a formation current of 18 A for 18 hours to complete the lead storage battery of Comparative Example 1.

Comparative Example 2 Using a Pb—Ca alloy lattice,
An electrode group was formed by laminating six unformed negative electrode plates covered with a bag-shaped polyethylene separator and five unformed positive electrode plates using a Pb-Ca alloy lattice.

After disposing the electrode group in a battery case, an electrolytic solution was injected into the battery case to produce an unformed battery.

Next, this unformed battery was formed at a formation current of 18 A for 18 hours to complete the lead storage battery of Comparative Example 2.

Comparative Example 3 A lead-acid battery was completed in the same manner as in Comparative Example 1. 1100 polypropylene spheres having a diameter of 3 mm were floated over the electrolytic solution of the completed battery so as to cover the entire electrolytic solution, whereby a lead-acid battery of Comparative Example 3 was completed.

Comparative Example 4 An electrode group was completed in the same manner as in Comparative Example 1. The electrode group was placed in a battery case in which ribs were horizontally arranged on the inner wall of the battery case, and the lead storage battery of Comparative Example 4 was completed in the same manner as in Comparative Example 1 except for the above.

Example 1 An electrode group was produced in the same manner as in Comparative Example 1. As shown in FIG. 1, an oxygen gas impermeable membrane 2 made of polyethylene was disposed so as to cover almost the entire electrode plate group 1 except for the lower end from above. In this example, the space between the adjacent ear portions 3 is not covered with the oxygen gas impermeable film 2. Otherwise, the lead-acid battery of Example 1 was completed in the same manner as in Comparative Example 1.

Example 2 An electrode group was produced in the same manner as in Comparative Example 2. As shown in FIG. 2, an oxygen gas impermeable membrane 2 made of polyethylene was arranged so as to cover the upper part of the electrode plate group 1. Also in this example, the space between the adjacent ear portions 3 is not covered with the oxygen gas impermeable film 2. Otherwise, the lead storage battery of Example 2 was completed in the same manner as in Comparative Example 2.

The completed batteries were all JISD5301
And a capacity of 48 Ah of the format 55D23 described in (1). next,
After each battery is fully charged, 0.5 A at 75 ° C ambient temperature
Was charged at a constant current, and the amount of the electrolyte solution reduced was examined.

FIG. 3 shows the relationship between the charging time, which is the measurement result, and the liquid reduction amount. Since each battery is fully charged, all of the current flowing is used for electrolysis of water, and the electrolyte is reduced at a constant rate. The theoretical amount of water reduced by electrolysis is as shown in the figure. In Comparative Example 1, in addition to the reduced amount due to electrolysis, there was a reduced amount due to evaporation and self-discharge, and the reduced amount was larger than the theoretical reduced amount. Comparative Example 2 did not use antimony and thus had less self-discharge, and the amount of liquid reduction was smaller than that of Comparative Example 1. In Example 1 and Example 2, the oxygen gas impermeable film 2 is covered on the electrode group 1, so that the oxygen gas generated during overcharge is sufficiently dispersed and dissolved in the electrode group 1 and absorbed by the negative electrode plate. As a result, the apparent gas generation amount is reduced, and the amount of liquid reduction is smaller than the theoretical amount of liquid reduction. Furthermore, in Example 1, although antimony was used, the amount of liquid reduction due to self-discharge was large.
The self-discharge is suppressed by the absorption of the oxygen gas sufficiently dispersed and dissolved in the negative electrode plate, so that the amount of liquid reduction is greatly reduced as compared with the second embodiment.

Next, each battery was allowed to stand at 75 ° C. in a fully charged state, and the amount of electrolyte reduction at that time was examined.

FIG. 4 shows the relationship between the standing time, which is the measurement result, and the amount of liquid reduction. In Comparative Example 1, antimony is deposited on the negative electrode plate, a potential difference between lead and antimony is locally generated, self-discharge is promoted, and hydrogen is generated from the negative electrode plate by self-discharge, so that the amount of the electrolytic solution is largely reduced. Comparative Example 2
Since antimony does not exist in the battery, self-discharge is small and the amount of liquid reduction is small. In Examples 1 and 2, the oxygen gas is sufficiently dispersed and dissolved in the electrode plate group 1 or the electrolytic solution. Therefore, an absorption reaction of the oxygen gas occurs in the negative electrode plate to suppress self-discharge and reduce the amount of liquid reduction. Reducing.

Next, each battery was subjected to 25 A at an ambient temperature of 75 ° C.
After charging for 4 minutes, charging and discharging at 14.8 V for 10 minutes were defined as one cycle, and this was repeated, and the amount of electrolyte reduction in each cycle was examined.

FIG. 5 shows the relationship between the number of cycles, which is the measurement result, and the amount of liquid reduction. In Comparative Example 1, the amount of liquid reduction was large due to the deposition of antimony having a low hydrogen overvoltage on the negative electrode plate.
In Comparative Example 2, the amount of liquid reduction was smaller than in Comparative Example 1 because no antimony was present. In Examples 1 and 2, since oxygen gas is dispersed and dissolved in the electrode plate group 1 or the electrolytic solution, an absorption reaction of the oxygen gas occurs in the negative electrode plate to reduce gas generation. Furthermore, self-discharge is suppressed, and hydrogen generation from the negative electrode plate is reduced.

[0045]

In the lead storage battery according to the present invention, the electrode group is covered with the oxygen gas impermeable film, so that the oxygen gas generated at the time of charging and dispersed in the electrode group is covered by the oxygen gas impermeable film. The oxygen gas can be held, and convection can be caused by the oxygen gas impinging on the oxygen gas impermeable membrane. Therefore, the oxygen gas can be sufficiently dispersed and dissolved in the electrode plate group. This oxygen gas moves to the surface of the negative electrode plate, and by absorbing this, the amount of reduction of the electrolytic solution can be suppressed. In addition, the absorption of the oxygen gas into the negative electrode plate can suppress the generation of hydrogen on the negative electrode plate due to self-discharge, and can significantly suppress the decrease in the electrolyte.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a process of covering an entire electrode group with an oxygen gas impermeable film in a first example of an embodiment of a lead storage battery according to the present invention.

FIG. 2 is a perspective view illustrating a process of covering a part of an electrode plate group with an oxygen gas impermeable film in a second example of the embodiment of the lead storage battery according to the present invention.

FIG. 3 is a comparison diagram showing the change over time in the amount of liquid reduction when the lead storage batteries of Examples 1 and 2 used in the test and Comparative Examples 1 to 4 are overcharged at a constant current.

FIG. 4 is a comparison diagram showing the change over time in the amount of liquid reduction during discharging of the lead storage batteries of Examples 1 and 2 and Comparative Examples 1 to 4 used in the test.

FIG. 5 is a comparison diagram showing the relationship between the charge / discharge cycle of each lead storage battery of Examples 1 and 2 and Comparative Examples 1 to 4 used in the test and the amount of liquid reduction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode group 2 Oxygen gas impermeable membrane 3 Ear part 4 Strap

Claims (3)

[Claims] 1. A lead-acid battery in which an electrode group formed by alternately stacking a negative electrode plate and a positive electrode plate via a separator is accommodated in a battery case, wherein the electrode group is formed of an oxygen gas through which oxygen gas in a bubble state does not pass. A lead storage battery characterized by being covered with an impermeable membrane. 2. A lead-acid battery in which an electrode plate group in which a negative electrode plate and a positive electrode plate are alternately stacked via a separator is accommodated in a battery case. A lead-acid battery, wherein the lead-acid battery is covered with an oxygen-impermeable membrane through which oxygen gas in a bubble state does not pass. 3. A lead-acid battery in which an electrode group formed by alternately stacking a negative electrode plate and a positive electrode plate via a separator is accommodated in a battery case, wherein only the upper part of the electrode group in the installation state has bubbles. A lead-acid battery, wherein the lead-acid battery is covered with an oxygen gas impermeable membrane through which oxygen gas does not pass.