JPH1140188A - Sealed-type lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed-type lead-acid battery with a long life time by suppressing lead sulfate of a negative pole plate. SOLUTION: An acid-resistant and oxidation resistant plate 4, an upper part of which is thicker than a lower part, is secured to the outside of a negative pole plate 2 arranged on the both sides of a group of electrodes. It is preferable that the thickness of the pole plate 4 have in its height direction a grade, which is not less than 3/4 of a draft required when molding of a battery jar. It is also preferable that the plate 4 be made of an adhesive and secure the negative electrode 2 to a battery jar 5.

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 A sealed lead-acid battery absorbs and fixes an electrolytic solution to a liquid retaining material called a retainer.
It has a structure that does not contain excess electrolyte and does not overflow when the battery is installed in any position. As described above, since the amount of the electrolyte is minimized, lead sulfate of the negative electrode plate and a decrease in sulfate groups in the electrolyte due to lead sulfate cause a decrease in capacity. The production of lead sulfate on the negative electrode plate is promoted for the following reasons.

[0003] (1) The draft of the battery case causes a difference in the amount of electrolyte between the upper and lower electrode groups, thereby promoting the production of lead sulfate. That is, the battery case is provided with a slope on the side surface in order to make the mold open and protrude well, and when the electrode group is compressed and inserted into such a battery case, the thickness of the electrode plate is almost completely reduced. Since it does not change, the lower part of the retainer has a smaller thickness than the upper part, and the lower part of the electrolyte is smaller than the upper part. As a result, the concentration of the electrolyte in the lower part of the electrode group is higher than that in the upper part, and a concentration cell is generated, and the production of lead sulfate is promoted.

(2) Due to the ribs provided in the battery case and the draft angle of the battery case, the negative electrodes at both ends of the electrode group have poor adhesion to the inner wall of the battery case, are exposed to oxygen gas, become lead oxide, and become sulfuric acid. Lead is easily generated. And the rate of lead sulphation is accelerated by a reduction in pressure during use. Japanese Unexamined Patent Publication No. 59-37650, Japanese Utility Model Application Publication No.
Japanese Patent Application Publication No. 9-66862 proposes that a resin plate having a gradient is inserted between a negative electrode plate at both ends of a pole group and a battery case. However, when the pressure decreases, the production of lead sulfate is suppressed. could not.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a long-life sealed lead-acid battery that suppresses lead sulfate of a negative electrode plate.

[0006]

In order to achieve the above-mentioned object, the present invention provides an anti-oxidation and anti-oxidation method in which the thickness of the upper part is larger than that of the lower part, outside of the negative electrode plates arranged at both ends of the electrode group. The sealed lead-acid battery is characterized in that the plate is disposed and fixed to the negative electrode plate. And it is preferable that the said board | substrate has a gradient of 3/4 or more of the draft required at the time of battery case shaping | molding in the height direction.

The plate may be made of an adhesive, and the adhesive is preferably bonded to the inner wall of the battery case.

[0008]

According to the first aspect, since the acid-resistant and oxidation-resistant plates are fixed to the outside of the negative electrode plates disposed at both ends of the electrode group, the surface of the negative electrode plate stays even when the pressure is reduced during use. Without being exposed to gas, the production of lead oxide and lead sulfate is suppressed. In addition, even if ribs are provided in the battery case, the surface of the negative electrode plate is not exposed to the gas.

According to the second aspect, when the gradient of the acid-resistant and oxidation-resistant plate is at least 3/4 or more, the draft required at the time of forming the battery case can be absorbed. Can be equalized. However, the slope of the plate is 1
In the case of / 2 or less, the draft of the battery case cannot be sufficiently absorbed, and the effect is significantly reduced.

According to the third aspect, the negative electrode plate outside the electrode group does not rise due to vibration or the like, the pressure applied to the electrode group does not decrease, and the internal resistance of the battery does not increase.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a sealed lead-acid battery A showing an embodiment of the present invention. In the figure, 1 is 3.2 mm in thickness. Positive electrode plate 115 mm in height and 144 mm in width, 2 is 2.0 mm in thickness, 115 mm in height and 14 in width
The 4 mm negative electrode plate 3 is a liquid retaining material mainly using glass fiber, and is laminated by sandwiching the liquid retaining material 3 between the positive electrode plate 1 and the negative electrode plate 2 to form an electrode group. Reference numeral 4 denotes a resin plate fixed to the negative electrode plates 2 disposed at both ends of the electrode group using an adhesive resin. The resin plate is fixed using an adhesive resin before filling the active material, but may be fixed after filling and drying. The adhesive resin is selected from resins having acid resistance and oxidation resistance typified by epoxy resin and the like and good adhesion to lead. Resin plate 4
Was made the same as the area of the negative electrode plate 2, and the thickness was made 0.25 mm thick at the upper part from the lower part, and had a uniform gradient from the upper part to the lower part (corresponding to a draft of about 3/4).
5 indicates a battery case. (Embodiment 2) A similar sealed lead-acid battery B was produced in the same manner as in Embodiment 1, except that the draft of the resin plate 4 was reduced to half.

Embodiment 3 Instead of the resin plate 4 of Embodiment 1, an adhesive was poured between the negative electrode plate 2 and the inner wall of the battery case 5, and the negative electrode plate 2 was fixed to the inner wall of the battery case 5. Otherwise, a sealed lead-acid battery C similar to that of the first embodiment was manufactured. The thickness of the adhesive was the same as the thickness of the resin plate 4 of the first embodiment.

(Comparative Embodiment) As shown in FIG. 2, the draft angle of the resin plate 4 is zero, that is, the resin plate 4 having the same thickness at the upper and lower portions.
A sealed lead-acid battery D similar to that of the first embodiment was prepared except that was used.

In this battery, as shown in FIG. 2, since the side wall of the battery case 5 expands upward, the lower part of the electrode group is compressed more than the upper part. The electrode group is housed in the battery case 5 with the upper part being larger than the lower part.

(Conventional form) Next, a sealed lead-acid battery E having a conventional structure in which no resin plate is inserted between the battery case and the negative electrode plates disposed at both ends of the electrode group was manufactured.

The batteries A, B, C, D,
E was charged with diluted sulfuric acid having a specific gravity of 1.320, and then charged for the first time to obtain a capacity of 29 Ah.

(Test) The batteries A, B, C,
The cycle life characteristics of D and E were examined under the same test conditions. Table 1 shows the results. The discharge was performed at a temperature of 40 ° C. and a DOD of 80% with a discharge current of 3 hours,
Charging is at 0.1C at a temperature of 40 ° C (C is 3 hours capacity)
To make the discharge amount 110%. The life was determined when the discharge capacity became 80% or less of the initial capacity, and the charge / discharge cycle was repeated until the life was reached. The results shown in Table 1 show the results converted at 25 ° C. based on this test.

[0019]

[Table 1]

As is clear from Table 1, the batteries A, B, C and the comparative battery D of the present invention have a longer life than the battery E of the conventional structure, and the batteries A having a gradient in the resin plate 4 or the adhesive. , B, and C showed about 18% or more improvement in life performance. This is because, in the battery E of the conventional structure, unchargeable lead sulfate accumulated on the negative electrode plates at both ends of the electrode group, the utilization rate of other negative electrode active materials was increased, and the capacity was reduced quickly.
In the batteries A, B, and C of the present invention, lead sulfate did not accumulate on the negative electrode plates at both ends of the electrode group, and in the battery A, since the amount of electrolyte solution between the upper and lower electrode groups was equal, the production of lead sulfate was suppressed more. It is. Since the battery B is a resin plate having a draft of 1/2, the draft of the battery case cannot be absorbed, and the life cycle is not much different from that of the battery D to which the resin plate 4 having no gradient is bonded. Was. Furthermore, for the battery C, the electrode group, particularly the negative electrode plates at both ends of the electrode group during lifting is prevented from rising, so that the tension applied to the electrode group does not change and the internal resistance does not increase. The cycle extends.

[0021]

As described above, according to the present invention, the negative electrode plates used at both ends of the electrode group are heat-sealed or adhered with an adhesive resin such that a plate having a draft resistance of acid resistance and oxidation resistance is outside the electrode group. Thus, the negative electrode active material is not converted to lead sulfate, and a sealed lead-acid battery having a longer life can be provided.

Further, when the draft is not less than 3/4, the above effect is excellent.

Further, when an adhesive is used in place of the plate, the assembling operation is simplified, and since the pressure of the electrode group does not change during use, the internal resistance does not change and a long-life sealed lead-acid battery is provided. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a comparative embodiment according to the present invention.

[Explanation of symbols]

 2 Negative electrode plate 4 Acid- and oxidation-resistant plate 5 Battery case

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhide Nakayama 6-6 Josai-cho, Takatsuki-shi, Osaka Inside Yuasa Corporation

Claims (3)

[Claims] 1. A sealed lead-acid battery in which an acid-resistant and oxidation-resistant plate whose upper part is thicker than its lower part is fixed to the outside of the negative electrode plates arranged at both ends of the electrode group. 2. The sealed lead-acid battery according to claim 1, wherein the thickness of the plate according to claim 1 has a gradient in the height direction that is equal to or more than ／ of a draft required for forming the battery case. 3. The sealed lead-acid battery according to claim 1, wherein the plate is made of an adhesive, and the negative electrode plate is fixed to an inner wall of the battery case.