JPS5916263A - Lead battery - Google Patents

Abstract

PURPOSE:To enhance the gas absorption rate of a lead battery by enabling a large quantity of oxygen gas generated in the positive plate to be gathered and delivered to the negative plate by making the surface of the separator member having larger penetrating holes in contact with the positive plate. CONSTITUTION:Plural pieces of separator members, which are prepared by forming penetrating holes having the maximum diameter of below 100mu in flexible materials, are stacked to make a separator. The thus made separator is placed between a positive and a negative plate, which are located 0.4mm. or more apart from one another, in close contact with them. Electrolyte is allowed to exist there in such an amount as it may at least flow there through. The negative plate may have an oxygen-gas absorbing function. It is not always necessary to provide a valve. Even when any decrease in the amount of the electrolyte is developed by some causes other than electrolysis of water, water can be supplied easily if necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-maintainable lead-acid battery that is capable of absorbing oxygen scum generated at the positive electrode plate by the negative electrode plate despite having a sufficient amount of flowing electrolyte. The purpose is to provide a high-performance, long-life, extremely low-cost, maintenance-free lead-acid battery without adding special expensive parts.

There have been many proposals regarding maintenance-free lead batteries. A typical example is the use of the so-called oxygen cycle, in which the electrolyte volume is made to be the same as or less than the pore volume of the electrode group to make it non-fluid, and the oxygen gas generated from the positive electrode plate is recombined with the negative electrode plate at the end of charging. There are some that have been made airtight by doing so. A similar technology is one in which the electrolyte is made into a colloid and hermetically sealed. These sealed lead batteries do not have a flowing electrolyte, so there is no leakage of electrolyte, so lead batteries can be used in any position, and their gas absorption efficiency is high, making them completely maintenance-free lead batteries. It can be said that there is. However, in these types of lead batteries, the injection amount is set so that the flowing electrolyte runs out, so the amount of electrolyte is small compared to the amount of active material in the positive and negative electrode plates, and the amount of electrolyte in this electrolyte is small. Battery capacity is limited by the amount of sulfuric acid, and the electrolyte evaporates during use, oxygen scum generated at the end of charging is released, and air enters the battery from the outside, causing oxygen in the air to evaporate. A valve is required to prevent the negative electrode plate from self-discharging due to a reaction between the gas and the negative electrode plate, and special measures are required for the terminal section to improve leakage resistance. At the same time, the battery case is required to have sufficient internal pressure resistance to withstand the opening pressure of the valve, so the material used for the battery case is limited, and the wall thickness of the case is thick. It is extremely difficult to apply this method to lead-acid batteries.

In order to compensate for this drawback of having a small amount of electrolyte, a structure in which an absorbing material for retaining electrolyte is placed around the electrode group has been proposed, as shown in US Pat. No. 4,119,772, for example. However, even these structures still require valves.

By the way, the inventors of the present invention published the patent application form 1983-. Research has been carried out on a method of applying a separator formed into a sheet shape mainly made of glass fibers having an average fiber diameter of 1 μm or less, as shown in Japanese Patent No. 58+3. As a result, this separator has been tested not only for conventional sealed lead batteries with non-fluidized electrolyte, but also for lead batteries that have a sufficient amount of fluid electrolyte under certain conditions. It has been found that even in a battery, oxygen scum generated from the positive electrode plate can move through the separator toward the negative electrode plate without escaping to the upper part of the electrode group, and be recombined by the negative electrode plate. This is because the separator is flexible and has a lot of fluff, so it is in very close contact with the electrode plate surface, and the pores on it are small, so there is a large resistance for oxygen gas to escape to the upper part of the electrode group. Rather, it is thought that this is because it moves obliquely in the thickness direction and reaches the negative electrode plate.

After researching the sludge absorption properties of various separators in the presence of a flowing electrolyte, it became clear that such sludge absorption occurs under the following conditions.

a. The separator must have enough flexibility and compressibility to come into close contact with the positive and negative electrode plates so as not to leave large gaps between itself and the irregularities of the active material on the surface of the positive and negative electrode plates.

b. It is larger than the substantial maximum pore diameter of the separator itself or the substantial maximum pore diameter of the void in its close contact surface with the positive and negative electrode plates.

C. The pore size of the separator itself is small. That is, the maximum pore diameter of the material is 100 μ or less, more preferably 40
Must be less than μ.

By meeting the above conditions, the oxygen residue generated on the positive electrode plate is moved in the thickness direction of the separator and reaches the negative electrode plate, rather than escaping from the interface between the separator and the positive electrode plate to the upper part of the electrode group. can do.

However, there are few separators that meet these conditions. For example, a conventional fiber-reinforced separator is not flexible and is too rigid, so that oxygen gas escapes from the gap between the positive electrode plate and the separator to the outside of the electrode group, and no dregs are absorbed. This is a microporous rubber separator or Taramink (product name: W,
The same result can be obtained even if a separator such as R, manufactured by Clase Co., Ltd.) is used.

On the other hand, when a sheet made of glass fibers with an average fiber diameter of 19 μm, which has been conventionally used as a glass mat for lead-acid batteries, is used as a separator, the maximum pore diameter is 50 μm.
1 jμ, which is so coarse that even if it is possible to bring it close to the surfaces of the positive and negative electrode plates, oxygen gas escapes to the upper part of the electrode group through the coarse pores, so that no gas absorption takes place.

Furthermore, if the pore size is large, the oxygen gas bubbles themselves become large, which causes electrical resistance, and the discharge characteristics of the battery are also unfavorable.

As a separator that meets these conditions,
As shown in Japanese Patent No. 5-5815, the fiber diameter is 1
A sheet formed mainly of glass fibers with a diameter of less than μ is extremely suitable. In addition, U.S. Patent No. 4-2
As stated in Roro No. 679 specification, 60-80%
It consists of perlite and 20-70% glass fiber,
Particle size of pearlite is ~100μ and fiber diameter of glass fiber is 0.6~1.0μ, Japanese Patent Publication No. 57-5
As shown in Publication No. 00040, 15-75% perlite, 20-70% glass fiber, and 5-20%
The particle size of perlite is 6 to 100μ, and the fiber diameter of glass fiber is 0.6 to 100μ.
1.0 μ, as shown in Japanese Patent Application Laid-Open No. 56-99968, fibrillar synthetic fibers with P water filtration of 50 LC or less are substantially 1 nf/y or more (fiber diameter approximately 2 μ
Approximately 10% of the glass fiber with a specific surface area of
Those mixed in the following proportions, and as shown in PCT Publication No. W o 8' 170 Roro 97, have a diameter of 0.1 to 5.5μ and a specific gravity of 2.46 y/
10-90% of acicular acid-resistant inorganic material larger than cc;
A material made of glass fibers with a fiber diameter of 10 μm or less and a synthetic fiber binder of 25% or less can be used.

Further, as a result of further research by the present inventors, it has been found that in order to further improve the scum absorption rate in such lead batteries, it is better to provide through holes in the separator in its thickness direction. That is, by providing the through holes, oxygen gas generated in the positive electrode plate moves through the through holes in the thickness direction and reaches the negative electrode plate more easily than through the separator and escapes to the upper part.

However, when a separator provided with such a through hole is used, there is a risk that the distance between the positive and negative electrode plates becomes short.

The present invention overcomes this problem and provides a lead battery with a sufficiently flowing electrolyte and a negative electrode plate with an oxygen gas absorption function, the maximum pore size being 11. ] Using a flexible material with a diameter of 0 μ or less, a separator made by stacking multiple separator materials with through holes in the material is placed between positive and negative electrode plates with a gap of 0.4 mm or more. Positive
The feature is that the separator is arranged in close contact with the negative electrode plate.

The invention will now be explained by examples and tests conducted using the examples.

Example 1 Width 11:llffm, height 1 made of Pb-Ca alloy
A grid of 1.5mm thick was used, with a thickness of 1.5mm according to conventional treatment.
An 8ffll+ positive electrode plate and a 1.4-thick negative electrode plate were created.

It consists of 80% by weight of glass fibers with an average fiber diameter of 05 μm and 20% by weight of glass fibers with an average fiber diameter of 13 μm, and has dimensions of 165 mm in width, 240 m in length, and a thickness of 0.5 mm under a load of 21 kg/dd. 5', +, two separator materials each having one through hole with a diameter of 0.1 mn+ per 5 rsm square are stacked on top of each other so that the through holes do not overlap as much as possible to form a separator. was bent into a U-shape, and the positive electrode plate was inserted inside. 4 positive electrode plates and 5 negative electrode plates sandwiched by this separator
A pole group was created by stacking the positive and negative electrode plates, adjusting the gap between the positive and negative electrode plates one after the other, and forming a strump connecting the ears and a pole column rising from the strut. The electrode group is housed in each of six cells without a saddle in a battery case made of polyolefin,
After connecting the cells according to a conventional method, a battery case lid made of polyolefin was bonded to the battery case by heat welding, and the poles were made to protrude from the through hole of the battery case lid to seal the gap. Next 1. ′
An electrolytic solution consisting of sulfuric acid having a specific gravity of 50 d was injected to a height that sufficiently immersed the electrode group, and an exhaust plug having an exhaust port was tightened to obtain an N540Z type lead battery A according to the present invention.

A partially cutaway front view of this is shown in FIG. In the drawing,
1 is a positive electrode plate, 2 is a negative electrode plate, filter is a separator, 4,
5 is each separator material. Further, 6 is a strap, 7 is a pole pole, 8 is a battery case, 9 is an inter-cell connection part, 10 is a battery case lid, 11 is an electrolytic solution, 12 is an exhaust plug, and 16 is an exhaust port.

A comparative test was conducted between the lead battery A according to the present invention and a conventional NB40Z type lead battery B using a grid made of a Pb-Ca alloy. This lead battery B is made using a 0.8 mm embossed Yumicron Se-Grator (product name) made by dissolving a two-component resin made in-house in a mixture of solvent and non-solvent and attaching it to a porous sheet such as polyester. From this, the solvent is volatilized to solidify the synthetic resin, and the non-solvent material is further volatilized, and the separator (with micropores formed where the non-solvent was) is bent into a U-shape, and the negative electrode plate is placed in between. The electrode group was formed by sandwiching the positive electrode plate and the positive electrode plate, and the specific gravity of the electrolyte was 1°26d.

These lead batteries were tested according to JIS-n5501, and the 20 hour rate capacity and -15
The duration and 5-grain voltage in rapid discharge with a discharge current of 15t at 'C and )A were determined. Further, these lead batteries were charged at 10.5 A for 100 hours, and the scum absorption rate was determined from the weight loss. The results are shown in Table 1.

As shown in Table 1, the soot absorption rate is the percentage calculated by subtracting the reduced weight from the theoretical liquid loss amount calculated when charging a lead-acid battery under the same conditions, and taking this value as 100 of the theoretical liquid loss amount. This is the displayed value.

The following can be seen from the results in Table 1. Lead battery A has the same initial performance as lead battery B (here, it has the same low rate discharge capacity characteristics, and furthermore, the discharge duration is the same in terms of low temperature high rate discharge characteristics, but the discharge voltage characteristics are Very good.And this is because the porosity of its separator is 80-9.
This is thought to be due to the extremely low electrical resistance, which is as high as 7%.

It is also seen that lead battery A has dregs absorbing properties.

In addition, these lead batteries are JIS-D53 [1 and 5AE
Figures 2 and 6 respectively show changes in capacity and changes in 30-second mouth pressure with respect to the number of times of charging and discharging when an alternate charging and discharging test was conducted under the conditions of -J240a.

In Figures 2 and 6, lead battery Aa is lead battery A that has been appropriately refilled with water within the range of its appropriate electrolyte level, lead battery An is one that has not been refilled with water at all, and lead battery Ba is one that has not been refilled with water at all.
and Lead battery Bn indicate lead battery B with and without water replenishment, respectively.

The following can be seen from Figures 2 and 6. That is, lead battery A
Compared to lead battery B, its lifespan is superior regardless of whether or not water is added. This is thought to be because its separator has a superior active material retention function, and the active material does not fall off even after repeated charging and discharging. It will be done.

It can also be seen that lead battery A has gas absorption performance and exhibits excellent performance even without fluid replacement.

Example 2 A separator material was formed by making through holes in the same material as the separator material used for lead battery A using a device as shown in FIG. That is, the material 14 was guided onto an endless heald 15 having a rubber band attached to its upper surface, and a through hole was made with a blade 17 provided on a roll 16. The through hole is 15 mm x 1. OQ mm,
15 mm x 0.05 mm on the smaller side
It had a rectangular shape with a size of . Further, the number of through holes was one per five squares of the material.

The two sheets of separator material are placed one on top of the other so that the cut directions of the through holes are perpendicular to each other, and the separator is arranged so that the side with the larger through hole faces toward the positive electrode plate, using the same method as for lead battery A. A lead battery C according to the present invention was obtained by constructing an electrode group.

When a test similar to Test 1 was conducted on lead battery C, the results shown in Table 2 were obtained.

Table 2: In other words, in the lead-acid battery according to the present invention, the amount of electrolyte needs to be added to the extent that the electrode group is sufficiently immersed.

This is because if the electrolyte level becomes too low, the electrolyte will no longer flow like in conventional sealed lead batteries, leaving the negative electrode plate exposed. This is because the battery absorbs even oxygen from the air and self-discharge progresses.

Therefore, in the lead-acid battery of the present invention, it is necessary to have an electrolytic solution that flows sufficiently to leak, rather than in an amount that would leave the negative electrode plate half dry.

However, a flowing electrolyte is not required in excess.

In other words, in conventional non-maintainable lead batteries for automobiles, an electrolyte of about 200°C was provided on the electrode group in order to extend the water replenishment period, but the lead battery according to the present invention has gas absorption performance, so this electrolyte It is possible to reduce the amount to A or less, and it is possible to make the battery smaller and lighter, and it is also possible to improve the weight efficiency and volumetric efficiency of maintenance-free lead batteries.

Furthermore, the lead battery according to the present invention does not necessarily require a valve, and even if the electrolyte decreases due to causes other than water electrolysis, it is possible to easily replenish water if necessary.

In the lead-acid battery according to the present invention, the narrower the gap between the positive and negative electrode plates, the higher the waste absorption ability, but if it is narrower than 0°4 am, there is a risk of short circuit between the positive and negative electrode plates. It is better if it is wider than 0.4.11+. The gap between the positive and negative electrode plates is determined depending on the required capacity and waste absorption efficiency, but is usually about 5 mm or an upper limit.

By the way, a separator made by stacking a plurality of separator materials is extremely effective in preventing short circuits. At this time, it is more effective to overlap the separator materials while shifting the positions of the through holes.

In principle, it will be effective if the size of the through-hole in the separator material used in the lead-acid battery of the present invention is larger than the maximum hole diameter of the material of the separator material before the through-hole is provided.

By the way, the maximum pore diameter of the separator material shown in Japanese Patent Publication No. 58-16 of 1982 has a maximum pore diameter of 64 microns, and it is understood that providing through-holes larger than this pore diameter is effective for gas absorption. However, the maximum hole diameter referred to here is not the direct through hole, and from this, the diameter of the direct through hole mechanically provided in the separator material used in the lead-acid battery of the present invention is approximately 0 μ, and its ventilation resistance is became smaller, and the effect of improving gas absorption efficiency was recognized. However, if the through hole is too large, for example larger than 2500 μm, there is a risk of short circuit between the positive and negative electrode plates, which is not preferable.

This point can be summarized as follows. In other words, the size of the through-hole must be such that any circle with a diameter of 0μ or less can pass through it, and it cannot pass through any circle with a diameter of 2500μ or less. In other words, it is necessary that all of the line segments partitioned by the through hole passing through any point of the through hole have a diameter of 60μ or more, and at least one of them must have a diameter of 2500μ or less.

Based on this idea, the shape of the through hole may be an elongated shape such as a rectangle with a short side width of 60 to 2,500 μm.In fact, such a shape makes it easier to take up a larger area of the through hole, so the oxygen is more effective in reaching the negative electrode plate.

In the separator material for lead batteries according to the present invention, by bringing the surface with particularly large through holes into contact with the positive electrode plate, oxygen sludge generated on the positive electrode plate can be collected and more of it can reach the negative electrode plate, improving the scum absorption rate. It is extremely effective on

As described above, the lead wire according to the present invention can easily have a scum absorption function, has high performance, long life, and low price.
In addition, it does not require a sealed structure and can be used for various purposes such as automobiles and stationary applications, and has high industrial value.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view of an embodiment of the present invention, and Figs. 2 and 6 show alternate charging and discharging tests of a lead battery according to the present invention and a conventional lead battery under the conditions of JIS-n5501 and 5AEJ240a, respectively. FIG. 4 is a graph showing the change in capacity and the change in 60-second mouth pressure with respect to the number of charging and discharging operations, respectively. FIG. 4 is a front view showing an embodiment of the method of making through holes in the separator according to the present invention. 1...Positive electrode plate 2...Negative electrode plate...Separator 4, 5...Separator material 11...Electrolyte solution Applicant Yuasa Battery Co., Ltd. Charge/discharge count (~) Figure 2 20004000600 (18000+0000120
0014000 Charging and discharging times (-) Figure 3 Figure 4

Claims (1)

[Claims] 1) A lead battery having the following requirements a to e. a. Use a separator made of a flexible material with a maximum pore diameter of 100 μm or less and a plurality of separator materials stacked together with through holes formed in the material. b. The gap between the positive and negative electrode plates is 0.4-m or more. A separator must be placed closely to the C0 positive and negative electrode plates. d. The electrolyte is present at least to the extent that it flows. e. The negative electrode plate must have an oxygen sludge absorption function. 2) The lead battery according to claim 1, wherein the separator material has a maximum pore diameter of 40 μm or less. (b) The lead-acid battery according to claim 1, wherein the material of the separator material is formed into a sheet shape mainly made of glass fibers with a fiber diameter of 1 μm or less. 4) The lead battery according to claim 1, wherein the separators are stacked one on top of the other with the positions of the through holes of the separator materials evenly aligned. 5) According to claim 1, all of the line segments partitioned by the through hole that pass through any point of the through hole are 0 μ or more, and at least one of the line segments is 2500 μ or less lead battery. 6) The lead battery according to claim 5, wherein the through hole is elongated. 7) The lead battery according to claim 6, characterized in that a plurality of separator materials are arranged so that the cutting directions of the through-holes cross each other.