JPH03176965A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To improve capacity efficiency, extend the life for use in floating, and improve the charge/discharge efficiency by sandwiching a woven fabric with two frame-shaped or lattice-shaped lead plates, and partially penetrating and connecting them. CONSTITUTION:A nonwoven fabric sheet 1 formed by plating lead on the surfaces of glass fibers by the wet process is sandwiched from both sides with positive electrode plate lattices 2 made of a Pb-Sn alloy and expand-machined, it is pressurized, pressed and pinched, they are partially spot-welded 5 to connect skeletons of the lattices 2, and two single electrode plates 4 allowing the contact current collection from the sheet 1 are integrated to obtain a current collecting member. Paste is impregnated, aged and hardened to obtain an unformed positive electrode plate. The positive electrode plate is kept in contact with the sheet 1 for electron conduction, and it can be discharged by a lug 3 made of a lead alloy. The positive electrode plate, a negative electrode plate and a separator are combined to form an electrode group, it is inserted into a battery jar, a cover is stuck, and an electrolyte is filled to obtain a lead-acid battery.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sealed lead-acid battery, which is used as a backup power source for computers, communication equipment, etc., and is particularly required to have a long life when used as a float. It is related to.

Conventional technology and its problems Sealed lead-acid batteries normally move oxygen gas generated on the positive electrode plate at the end of charging to the negative electrode plate, react with the negative electrode active material, consume the oxygen gas, and put the negative electrode plate in a discharge state. The so-called "02 cycle p" is used to suppress the generation of hydrogen gas from the negative electrode plate.

The capacity of a sealed lead-acid battery is generally determined by the electrolyte contained in the electrode group consisting of a positive electrode plate, a negative electrode plate, and a separator.
The lifespan is determined by the expansion of the electrolyte, the sulfation of the negative electrode plate, the softening of the positive electrode active material, the corrosion of the positive electrode grid, and the growth (so-called elongation of the electrode plate) under the strap. It is dominated by short circuits between the positive and negative polar plates. In particular, the life when using a float is mainly controlled by corrosion of the positive electrode grid and corrosion of the positive and negative electrode plates under the strap due to growth. Conventionally, in order to improve this life mode, (1) by increasing the thickness of the positive electrode plate itself,
Control the amount of growth.

(2) In order to improve the corrosion resistance of the lattice and increase its mechanical strength, the amount of Sn is increased.

(3) Push the insulating resin short-circuit prevention plate under the electrode group strap of the negative electrode plate.

(4) Make the size of the positive electrode plate sufficiently smaller than the internal dimensions of the electric bridge so that it can be grown.

The following methods have been adopted. However, in (1), the positive electrode plate becomes thicker, making the battery larger and heavier.
(2) is expensive and has problems with castability;
) method has the effect of delaying the arrival of guests by 1υ.
Although expected, the growing lattice may deform the electric dandelion, and (4) has the disadvantage that the size of the electrode plate becomes smaller, resulting in a decrease in battery capacity.

Pemet type electrode plates used in lead-acid battery plates are usually manufactured by applying a paste-like active material to a cast or expanded lead alloy grid, then aging, drying, and chemically forming it. However, due to limitations in the manufacturing method of this lattice, the bones that make up the lattice cannot be made very thin, so the ratio of the lattice to the electrode plate cannot be reduced.

This means that the ratio of active material per unit volume of the electrode plate cannot be increased, which means that the capacity obtained as a battery will be small.Furthermore, since the lattice mesh becomes coarser, the active material and current collector It has the disadvantage that the charging and discharging efficiency is low because the distance is long.

In addition, since cast or expanded lattices have a small contact area with the active material, especially in the case of antimony-free alloys, a so-called "barrier layer" in which the lattice corrosion layer preferentially discharges over the active material may occur, resulting in an early stage. The disadvantage is that it has a limited lifespan.

OBJECT OF THE INVENTION The object of the invention is to overcome these drawbacks, and to provide an inexpensive sealed lead-acid battery that has excellent volumetric efficiency and a long life when used as a float.

Furthermore, the present invention is particularly advantageous in that the lattice corrosion layer is prioritized in the case of antimony-free alloys in which the lattice bones are made extremely thin and their proportion to the electrode plates of the lattice is reduced to improve charging and discharging efficiency. The object of the present invention is to provide a sealed lead-acid battery that does not have the disadvantage of causing a so-called "barrier layer" that discharges and prematurely reaching the end of its life.

The sealed lead-acid battery according to the present invention has a negative electrode plate whose connecting ear is made of lead or a lead alloy, and whose positive electrode plate has a conductive coating attached to the surface of non-conductive m-fibers. A nonwoven fabric made of conductive fibers is made conductive, and two frame-shaped lead plates or lattice-shaped lead plates are used to collect current from the nonwoven fabric by sandwiching the nonwoven fabric from both sides so that electrons can move between the nonwoven fabric and the nonwoven fabric. It consists of a current collecting member integrated with the plate, and an active material impregnated in the current collecting member, and the two frame-shaped lead plates or lattice-shaped lead plates partially penetrate the nonwoven fabric. It is preferable that at least one of the two frame-shaped lead plates or the lattice-shaped lead plate has a connecting tab, and the positive electrode plate and the negative electrode plate are connected to each other. are superimposed on 20 with a separator interposed therebetween at a pressure of 9/dm2 or more.

Example 1 The surface of a glass fiber having a diameter of 0.5 μm was plated with lead to a thickness of 0.2 μm, and a continuous nonwoven fabric sheet 1 was prepared by paper-forming this by a method. This nonwoven fabric sheet 1 is 2 (H9/
Thickness under pressure of dm2 til, 211ffl.

The porosity was 92% and the maximum pore size was 18 μm. Separately, P b -0,06wt%0a-0,5wt
A grid 2 for an expanded positive electrode plate made of a %Sn alloy and having a size of 6 was prepared. This grid 2 has a thickness of 0.7 mm, and as shown in FIG.
It consists of two monopolar plates 4 connected by.

Using this grid 2, the nonwoven fabric sheet 1 is pressed, crimped, and clamped by sandwiching it from both sides, and spot welding is carried out partially to join the pipes of the grid and to enable contact current collection from the nonwoven fabric sheet 1. A current collecting member was obtained in which two monopolar plates 4 were integrated.

In addition, 5 is a spot welding part. Next, this was impregnated with a paste, aged and hardened to obtain an uncured modified electrode plate A according to the present invention. The dimensions of the electrode plate were 38 mm wide, 68 mm long, and 1.5 mm thick. Unformed intimidating electrode plate A is non-woven fabric sheet 1
It is in contact with the battery so that it can conduct electrons, and can be charged and discharged using the ear 3 made of a lead alloy.

A conventional unconverted high-pressure electrode plate B having the same dimensions was obtained by casting using a conventional method without using a conductive nonwoven fabric.

Two types of positive electrode plates obtained in this way, a negative electrode plate prepared by the conventional method, and 90% glass fiber with a diameter of 1 pm or less,
Combined with a paper-made separator made of 10% glass fiber with a diameter of 19 pm to form a pole group, insert it into 'ti & cypress, glue the lid, and inject electrolyte to obtain two types of unformed sealed lead-acid batteries. Ta. Next, this battery is integrated into a shield to form a sealed lead-acid battery A according to the present invention and a conventional sealed lead-acid battery B.
I got it. At this time, the force with which the separator pressed the electrode plate, ie, the pressure, was 30 ke/dm2 for both batteries.

When the capacity of the obtained battery was tested, the results shown in Table 1 were obtained. Note that the capacity test was based on the capacity of the conventional sealed lead acid battery B of 4 AH/20 HR, and the sealed lead acid battery A according to the present invention was also tested under the same conditions.

Table in the margin below: When these two types of sealed lead-acid batteries were subjected to a float life test, the results shown in FIG. 2 were obtained. The float life test was conducted by continuously overcharging at a constant voltage of 2.30V per cell, and
Capacity was checked at a weekly rate of 5 hours. The ambient temperature was 40° C. for acceleration. Note that, for convenience, the plotting in the figure was performed every 6 weeks, and the capacity was expressed as a percentage (%) of the initial capacity (the same applies hereinafter).

Example 2 Instead of the nonwoven fabric 11 used in Example 1, a diameter of 0.
A continuous nonwoven fabric notebook was prepared by wet papermaking using a fiber coated with stannic oxide to a thickness of approximately 0.2 μm on the surface of a 5 μm single glass fiber. For this exposure, a metal tin plate was doped with about 45 mo/l'% of fluorine. This nonwoven fabric sheet and pb-o used in Example 1, 06wt%
ca-o, swt%Sn alloy color expanded positive electrode plate grid, processed, crimped and clamped with the non-woven fabric sheet sandwiched from both sides, and partially spot welded to connect the tubes of the grid. While bonding, contact current collection from the nonwoven fabric sheet is made possible, and then this is impregnated with paste, aged and cured to obtain the uncured modified electrode plate A sealed lead acid battery X was obtained.

The strain pressure was 5Gkq/dm2. The dimensions of this electrode plate were a width of 43 mm, a length of 75 mm, and a thickness of 1.5 mm.

The internal dimension of the power supply used, facing the positive plate grid, is 4 in the width direction.
5, the margin in the width direction of the electrode plates was 2 degrees in the case of the sealed lead-acid battery X, and 7 degrees in the case of the conventional example. Further, the distance between the lower surface of the negative electrode plate group stopper and the upper part of the positive electrode plate rib was 5 distances in the case of the present invention, and 12 distances in the case of the conventional example. Furthermore, the short-circuit prevention plate was not used in the sealed lead-acid battery X of the present invention, but was used in the case of the conventional sealed lead-acid battery B.

The capacity of the obtained battery was as shown in Table 2. Further, when this sealed lead acid battery X was subjected to a float life test, the results shown in FIG. 2 were obtained. The float life test was the same as in Example 1.

Table 2 Example 3 Unformed positive electrode plate X according to the present invention used in Example 2, negative electrode plate prepared by conventional method, and glass fiber 9 with a diameter of 1 μm or less
0%, and a paper-made separator made of 10% glass fiber with a diameter of 15 μm to form a pole group.
Sealed lead-acid batteries with different pressures are manufactured using separators of various weights. D, E and F were obtained. The strain pressures of these batteries were 0: 10 kL; I/dm2 D: 20#9/dm2 E: 40 kg/c1m2 F: 50 kg/dm2.

When these four types of sealed lead-acid batteries were subjected to a float life test, the results shown in FIG. 3 were obtained. Float life test
The same as in Example 1 was used.

The positive electrode plate used in the sealed lead-acid battery of the present invention is a nonwoven fabric made of conductive fibers that has been made electron conductive by attaching a conductive film to the surface of nonconductive fibers, and is made of a nonwoven fabric that can transfer electrons. A current collecting member integrally composed of two frame-shaped lead plates or lattice-shaped lead plates that collect contact current from the nonwoven fabric with a nonwoven fabric sandwiched between the nonwoven fabric from both sides, and an active material impregnated with the current collecting member 1. and two frame-shaped lead plates or lattice-shaped lead plates are constructed by penetrating the non-woven fabric and partially joining each other, and the connecting ears of the negative electrode plate are made of lead or a lead alloy. There is.

The nonwoven fabric that forms part of the current collector must be electronically conductive. Example 1 to obtain an electronically conductive nonwoven fabric
As shown in Example 2, the surface of glass fiber, which is a non-conductive fiber, may be plated with lead and then formed into paper using a wet process. Alternatively, as in Example 2, a fiber whose surface is coated with tin oxide may be used as a single glass fiber. It may also be wet-formed. Most preferably, the coating does not take part in the charging/discharging reactions of the battery, is stable over a long period of time, does not corrode, and has high conductivity. In this respect, the oxidized second
The most suitable coating is tin doped with antimony trioxide or fluorine.

Naturally, it is not inconceivable to use lead fiber itself in order to obtain an electronically conductive non-woven fabric. It would be ideal if a non-woven fabric made from lead fiber itself could be used. However, when lead fibers are used and made into a non-woven fabric, the density is high and the volume filled with active material is not as large as in the lattice obtained by conventional casting or expanded banding methods. Not only is it not possible to increase the capacity, but the strength is low and the handleability is also poor, which is not preferable.

Therefore, the preferred non-conductive fibers are those with high mechanical strength and high porosity when made into a non-woven fabric, and although the fine glass fibers used in the examples are optimal, Any material that is stable in the oxidizing atmosphere of a lead-acid battery can be used, including potassium titanate Limeka (which is commercially available from Ohita Kagaku ■ under the trade name Tismo). The diameter of the fibers used is preferably small in order to increase the contact density with the active material. The recommended diameter is 0.2μ
m to 20 μm1, preferably 0.5 μm to 5 μm,
The sheet is formed from single fibers having a length of 0.1 to 5 tnm using a wet method. In this case, a binder may be used if necessary to improve handling properties, but it should be kept to a minimum in order to ensure conductivity with the active material.

In order to construct one piece of this non-woven fabric and two frame-shaped lead plates or grid-shaped lead plates that sandwich the non-woven fabric from both sides and collect current from the non-woven fabric by contact so that electrons can move, the two frames are used. The shaped lead plates or lattice shaped lead plates must pass through the non-woven fabric and be joined to each other at some points. This is necessary to ensure complete current collection through contact with the non-woven fabric and to maintain it throughout the life of the battery. In addition to spot welding shown in the example, resistance welding, soldering, etc. can be used to ensure the integration of two frame-shaped lead plates or lattice-shaped lead plates by penetrating the nonwoven fabric at a portion.
mA method can be adopted.

This electronically conductive nonwoven fabric is pressed, crimped, and sandwiched from both sides to enable the movement of electrons from the nonwoven fabric.2
The frame-shaped lead plate or lattice-shaped lead plate is not only formed by the Echinu band method shown in the embodiment, but may also be formed by punching or casting. For the frame-shaped lead plate or grid-shaped lead plate, pure lead, Pb-Ga5, or Pb-(3a-8n series lead alloy) can be used.

Furthermore, the frame-shaped lead plate or grid-shaped lead plate must have at least one connecting ear. Since the negative electrode grid of the sealed lead-acid battery according to the present invention is made of lead or its alloy, it is preferable that the ears of the positive electrode grid also be made of lead or its alloy.
This is because it can be conveniently connected by a method such as a strap.

The sealed lead-acid battery according to the present invention has a volumetric efficiency of about 12% according to Example 1 and about 2% according to Example 2 compared to conventional products.
8% is also excellent. This is because according to the present invention, the pore volume of the lattice is increased by nearly 10% compared to the conventional one, and there is no need to take into account the Grone life limit of the positive electrode lattice when using a 70-meter electrode. N of the same size
This is because it is possible to insert a larger size electrode plate into the tank than in the past. This is because in the case of conventional cast grids, the filling volume ratio of the active material was about 80%,
In the case of the positive electrode grid used in the sealed lead acid battery of the present invention,
Even if the nonwoven fabric and the frame-shaped lead plate or grid-shaped lead plate are combined, the ratio can be as high as nearly 90%, and since the nonwoven fabric is electronically conductive, the number of contacts between the active material and the current collector can be reduced. This is because there are many orders of magnitude more.

Moreover, even if the ratio of 1 grid is reduced, the current used for corrosion is still small and the current used for charging the active material is large, resulting in an improvement in charging efficiency, and its corrosion resistance. It is presumed that this is because he himself is exceptionally good. With this configuration, the number of contacts between the active material and the current collector increases by an order of magnitude, improving charging and discharging efficiency, and giving priority to the lattice corrosion layer that antimony-free alloys have. The so-called "
This overcomes the shortcomings of "barrier layer" formation and premature end of life.

In fact, the causes of the shortened lifespans of sealed lead-acid batteries A and − Despite not using a toe prevention plate,
No short circuit occurred at the bottom of the negative electrode tube. This is due to the high porosity of the nonwoven fabric sheet made of fibers coated with tin oxide, and the coating does not take part in the charging/discharging reactions of the battery, making it stable and free from corrosion, improving charging efficiency. It is presumed that this effect is due to the fact that it has excellent corrosion resistance.

In order to continue to maintain the electrical connection between the nonwoven fabric and the frame-shaped lead plate or grid-shaped lead plate constituting the positive electrode grid, the tension should be 20 k'V' dm2 or more, more preferably 30 &g.
/dm2 or more. Tight pressure is 20kg/dm2
If it is lower than 18-, the electrical connection between the nonwoven fabric and the frame-shaped lead plate or grid-shaped lead plate may be lost if the non-woven fabric is overcharged for a long period of time. The tension is 20k (7/dm2 or more, more preferably 30kg/dm2 or more)
This is because if it is dm2 or more, the electrical connection between the nonwoven fabric and the lead grid can be maintained. This is shown in Example 5.
It is clear from this.

The sealed lead-acid battery according to the present invention has a lattice S
There is no need to increase the amount of n, there is no need for a short-circuit prevention plate, and the cost is extremely low.

Effects of the Invention As detailed above, according to the present invention, it is possible to provide an inexpensive sealed lead-acid battery that is particularly excellent in volumetric efficiency and has a long life when used as a float. By making the bones extremely thin and making the ratio of the lattice to the electrode plates small, the efficiency of charging and discharging is improved, creating a so-called "barrier layer" where the lattice corrosion layer in the case of antimony-free alloys discharges preferentially. Since it is possible to provide an inexpensive sealed lead-acid battery that does not have the disadvantage of premature end of life, its industrial value is great.

[Brief explanation of drawings]

Fig. 1 is a cutaway perspective view of the main part showing the structure of the electrode plate used in the sealed lead-acid battery of the present invention, Fig. 4 is a side view of the same, and Figs. 2 and 6 show the float life characteristics of the sealed lead-acid battery. FIG. Battery A: Sealed lead-acid battery according to the present invention Battery X: Sealed molten lead @ battery according to the present invention Battery B: Conventional sealed lead-acid battery Battery Ci: Sealed type according to the present invention assembled under a pressure of 10#/dm2 Lead acid battery. Battery D: A sealed lead-acid battery according to the present invention assembled under a pressure of 20 kg/dm2 Battery E: A sealed lead-acid battery according to the present invention assembled under a pressure of 4 kg/dm2 Battery F: A sealed lead-acid battery according to the present invention assembled under a pressure of 50 kg/dm2 A sealed lead-acid battery according to the present invention assembled with

Claims (1)

[Claims] 1) The connecting ear of the negative electrode plate is made of lead or a lead alloy, and the positive electrode plate is made of conductive fibers made electronically conductive by attaching a conductive film to the surface of the non-conductive fibers. and two frame-shaped lead plates or lattice-shaped lead plates that collect current from the non-woven fabric by sandwiching the non-woven fabric from both sides so that electrons can move between the non-woven fabric and the non-woven fabric. , and an active material impregnated in the current collecting member, and the two frame-shaped lead plates or lattice-shaped lead plates penetrate the nonwoven fabric and are partially joined to each other. lead-acid battery. 2) The sealed lead-acid battery according to claim 1, wherein at least one of the two frame-shaped lead plates or the two grid-shaped lead plates has a connecting ear. 3) The positive electrode plate and the negative electrode plate are separated by a separator and weigh 20 kg/
The sealed lead-acid battery according to claim 1 or 2, wherein the batteries are stacked together under a pressure of dm^2 or more.