JPH06176752A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To provide a sealed lead-acid battery for preventing deformation concomitant with reduction in the inner pressure of a storage battery in a battery jar consisting of plastic sheet, at least a part of which has gas barrier property, and also preventing liquid leak accident of an electrolyte, with which the battery capacity can be increased. CONSTITUTION:An electric jar 1 consisting of a plastic sheet 5, at least a part of which has gas barrier property, is provided. An isolating body is also provided, the thickness of which as pressurized at 0.5Kg/cm<2> in a wet condition by dilute sulfuric acid is 85-95% of the thickness as pressurized at 0.1Kg/cm<2> in a dry condition, and the porosity of which as pressurized at 0.5Kg/cm<2> is no less than 86%.

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 in which at least a part of a battery case is made of a plastic sheet having a gas barrier property, and the change in the battery case thickness due to a decrease in internal pressure of the battery is prevented as much as possible. However, it is intended to prevent the overflow of the electrolytic solution and to increase the battery capacity.

[0002]

2. Description of the Related Art In recent years, lead-acid batteries have been hermetically sealed due to maintenance-free operation and application to various electronic devices. It is well known that in a sealed lead-acid battery, the internal pressure decreases due to the reaction between the oxygen gas in the battery and the negative electrode plate during standing.

[0003]

The sealed lead-acid battery is generally equipped with a fine fiber separator for separating the positive electrode plate and the negative electrode plate and holding the electrolytic solution. The separator is easily deformed by the compressive force. Cause For this reason, in a sealed lead-acid battery in which the battery case wall is made of a flexible plastic material, the battery case deforms inward as the storage battery internal pressure decreases, and compression deformation of the separator holding the electrolytic solution occurs. There is a risk that the electrolyte will be released from the separator and leak through the exhaust hole.

As a method for solving such a problem, it is considered effective to use a perfect rigid separator. However, in a retainer type sealed lead-acid battery with a structure in which all the electrolytic solution in the storage battery is held by the separator and the electrode plate, the contact between the positive and negative electrode plates and the electrolytic solution, which are indispensable for carrying out the battery reaction, In practice, it is difficult to obtain these sufficient contacts with a perfect rigid separator, as this is achieved by the intimate contact between the plates and the separator.

As another solution to this, it is conceivable to prepare a storage battery by using a thick fiber separator in advance and inject an amount of the electrolytic solution which does not overflow even if the storage battery is left for a long time. However, when using a very thick separator, the assembly workability is poor because the element group length during assembly is large, and the internal pressure of the storage battery does not decrease immediately after pouring and charging the storage battery and the separator is compressed. Therefore, the amount of electrolyte is significantly smaller than the holding capacity of the element, and since the electrolyte in the separator is locally dispersed and exists, the contact between the electrode plate and the electrolyte becomes insufficient, which is unsatisfactory. Discharge performance cannot be obtained.

The present invention has been made to solve the above problems, and an object of the present invention is to reduce the internal pressure of a storage battery in a battery case at least a part of which is formed of a plastic sheet having a gas barrier property. It is an object of the present invention to provide a sealed lead-acid battery that can prevent the accompanying deformation as much as possible, prevent the electrolyte from overflowing, and increase the battery capacity.

[0007]

Therefore, a battery case at least a part of which is made of a plastic sheet having a gas barrier property and a dilute sulfuric acid wet to a thickness of 0.1 kg / cm ² in a dry state when pressurized 0.5 Kg / cm ² the thickness of the pressurization in the state is 85 to 95% and, 0.5 Kg /
The above problem is solved by employing a sealed lead-acid battery including a separator having a porosity of 86% or more when cm ^{2 is} pressurized.

[0008]

The present invention will be described in detail with reference to Examples.

FIG. 2 is a view showing a cross section of a sealed lead acid battery having a battery case at least a part of which is formed of a plastic sheet having a gas barrier property. A method of manufacturing such a sealed lead-acid battery is already known as disclosed in, for example, Japanese Utility Model Publication No. 1-81861, so its detailed description will be omitted, but as shown in FIG. Using the tank 1, the positive electrode plate 2, the separator 3 and the negative electrode plate 4 are stacked in this order from the side (open surface) as shown in FIG. It is manufactured by welding.

Such a sealed lead-acid battery was manufactured by using the following separator. Sample A (prior art separator) 0.1 Kg / cm ² thickness ratio of 0.5 Kg / cm ² under pressure in a state of sufficiently wetting dilute sulfuric acid to the thickness of the pressurization is 74% of dry Yes, and having a porosity of 90% when pressed at 0.5 Kg / cm ² . Sample B (conventional separator) Similarly, the thickness ratio is 77% and the porosity is 90%. Sample C (changed rigidity) Similarly, the thickness ratio is 85% and the porosity is 79%. Sample D (modified stiffness) Similarly, the thickness ratio is 85% and the porosity is 86%. Sample E (Rigidity modified product) Similarly, the thickness ratio is 85% and the porosity is 92%. Sample F (modified rigidity) Similarly, the thickness ratio is 91% and the porosity is 90%. Sample G (modified rigidity) Similarly, the thickness ratio is 95% and the porosity is 86%. Sample H (Rigidity changed product) Similarly, the thickness ratio is 98% and the porosity is 86%.

After injecting a predetermined amount of dilute sulfuric acid into these storage batteries to charge them, 0.2 C after being left for 2 hours and left for 2 months
The discharge performance was measured. Also, for the items left for 2 months,
After discharging, place the storage battery so that the exhaust hole is on the
Constant voltage charging was performed with a V / cell, and the presence or absence of electrolyte leakage from the exhaust hole was examined. The results are shown in Table 1.

[0012]

[Table 1]

[0013] As apparent from the results, the thickness of 0.5 Kg / cm ² under pressure in a dilute sulfuric acid wet to the thickness of 0.1 Kg / cm ² under pressure in the dry state 85 ~ 95% and a porosity of 86% when pressed at 0.5 kg / cm ²
It can be seen that the storage battery using the separator as described above is superior to the conventional one in terms of initial capacity and anti-flooding performance.

[0014]

As described above, the sealed lead-acid battery according to the present invention comprises a battery case, at least a part of which is formed of a plastic sheet having a gas barrier property, and 0.1 kg / cm ² pressure in a dry state. 0.5kg / cm ² in dilute sulfuric acid wet condition, the thickness is 85-95
%, And the porosity at a pressure of 0.5 kg / cm ² is 8
It is characterized by having a separator of 6% or more. As a result, it is possible to provide a sealed lead-acid battery that is always stable and has a high discharge capacity, and that eliminates the risk of electrolyte leakage. The value of this invention is great.

[Brief description of drawings]

FIG. 1 is a view showing a battery case having one side surface opened.

FIG. 2 is a cross-sectional view of a sealed lead-acid battery having a battery case at least a part of which is formed of a plastic sheet having a gas barrier property.

[Explanation of symbols]

1 Battery case 2 Positive electrode plate 3 Separator 4 Negative electrode plate 5 Flexible plastic material with the side wall of the battery case sealed by heat welding

Claims (1)

[Claims] 1. A battery case, at least a part of which is formed of a plastic sheet having gas barrier properties, and has a thickness of 0.1 kg / cm ² in a dry state and 0.5 kg in a dilute sulfuric acid wet state with respect to a thickness when pressurized. / Cm ² Thickness when pressurized is 85
A sealed lead acid battery comprising: a separator having a porosity of not less than 95% and a porosity of not less than 86% when pressed at 0.5 kg / cm ² ;