JP3229214U - A container that houses the catalyst material, and a lead-acid battery that contains the container. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container for accommodating a catalyst layer material in a lead storage battery, which can suppress a decrease in the amount of electrolytic solution and which does not require redundant measures such as temperature control, and a lead storage battery using the same. To do. SOLUTION: A container 20 for accommodating a catalyst material 30 in a lead storage battery, the catalyst material contains a catalyst for promoting a reaction for producing water or water vapor from oxygen and hydrogen, and the container is covered with a film 40. With an opening, the membrane communicates oxygen, hydrogen and water vapor between the catalyst layer and the outside of the vessel and is oriented at an angle of 0 ° to 80 ° with respect to the direction of gravity. [Selection diagram] Fig. 3

Description

The present invention relates to a container for accommodating a catalyst material in a lead storage battery, and a lead storage battery including the container. In particular, the catalyst material comprises a catalyst that promotes a reaction that produces water or water vapor from oxygen and hydrogen.

In lead-acid batteries, especially lead-acid batteries for automobiles, a so-called open type structure in which an electrolytic solution such as dilute sulfuric acid can freely flow is widely used. Since a lead storage battery having this structure generates oxygen and hydrogen gas during charging, it has a vent (exhaust port) for releasing these gases to the outside. Otherwise, the gas pressure inside the battery will increase, leading to deformation and damage of the battery.
Further, such release of gas from the vent leads to a decrease in water in the electrolytic solution. When the amount of water in the electrolytic solution decreases, the total amount of the electrolytic solution decreases, the specific gravity of the electrolytic solution increases, the battery chemical reaction does not occur sufficiently, and the charging capacity and the discharging capacity decrease.
Various efforts have been made to address these issues.

Patent Document 1 discloses a catalyst component for a lead storage battery, and the catalyst component is
It has a catalyst layer containing a catalyst that promotes a reaction for producing water or water vapor from oxygen and hydrogen, and a configuration in which at least a part of water or water vapor generated by the catalytic reaction is condensed and recycled into the lead-acid battery. With this catalyst component, gas release from the electrolytic solution and a decrease in the amount of the electrolytic solution due to them can be suppressed, and a long life can be realized because the electrolytic solution does not decrease.

Patent Document 2 discloses a catalyst device that recombines the decomposition gas of the electrolytic solution. This catalyst device has the ability to filter and remove the catalyst poison (acidic electrolyte). More specifically, this catalyst device has a porous portion that allows gas to permeate but does not allow liquid to permeate, so that the catalyst poison (acidic electrolyte, etc.) does not reach the catalyst. It is described that the gas that has passed through the porous portion reaches the catalyst portion, is recombined, and can be recirculated through the porous portion.

JP-A-2017-201594 U.S. Pat. No. 7,326,489

As described above, in a general lead-acid battery, oxygen and hydrogen gas generated during charging are released from the vent to the outside, and the amount of electrolyte in the lead-acid battery is reduced. When the amount of the electrolytic solution is reduced, the battery chemical reaction is not sufficiently performed, and the charging capacity and the discharging capacity are reduced. Although it is not desired to be bound by a specific theory, the dilute sulfuric acid concentration in the electrolytic solution increases and the capacity decreases due to corrosion deterioration of the positive electrode plate, and the electrode plate becomes the electrolytic solution due to the decrease in the electrolytic solution level. It is conceivable that the discharge capacity drops sharply due to exposure from the negative electrode plate, and that the connection portion between the negative electrode plate and the strap is corroded.

Furthermore, the decrease in the amount of electrolyte is considered to lead to sulfation and osmotic short circuit. Sulfation means that lead sulfate produced by electric discharge cannot be sufficiently restored to lead dioxide and lead by charging, and coarse crystals of lead sulfate are generated. This coarse crystal is difficult to reduce to metallic lead, lowers battery performance and shortens battery life. In addition, this coarse crystal is also involved in osmotic short circuits. The coarse crystals grow on the electrodes into acicular crystals called "dendrites". As this dendrite continues to grow, it reaches the other electrode, causing a short circuit. This is a permeation short circuit, and subsequent charging and discharging cannot be performed. Conversely, by preventing a decrease in the amount of electrolyte, sulfation and osmotic short circuit can be prevented.

Patent Documents 1 and 2 disclose a catalyst component or a catalyst device for suppressing outgassing from an electrolytic solution and a decrease in the amount of the electrolytic solution due to them. That is, oxygen and hydrogen gas generated from the inside of the lead storage battery are recombined with water or water vapor by a catalyst and recirculated inside the battery.

However, even when these catalyst parts and catalyst devices are installed inside the lead-acid battery, the decrease in the amount of electrolytic solution may not be sufficiently suppressed. The decrease in the amount of electrolyte leads to the deterioration of the charge / discharge capacity and the damage inside the battery as described above. Therefore, it is strongly desired to suppress the decrease in the amount of electrolytic solution.

Further, the catalyst device of Patent Document 2 needs to be temperature-controlled to a relatively high temperature (about 70 to 90 ° C.), and can be used in an environment where it is constantly charged as used for backup of power supply equipment. However, it cannot be used in an environment where charging is discontinuous and temperature control is not possible. For example, the device of Patent Document 2 is not suitable for a lead storage battery for an automobile or the like because it may not be used in a constantly charged state or may be used even in a cold region.

In view of the above, the present invention provides a container for accommodating a catalyst layer material in a lead storage battery, which can suppress a decrease in the amount of electrolytic solution and does not require redundant measures such as temperature control. An object of the present invention is to provide a lead-acid battery used.

The present invention provides the following aspects.

[1]
A container that houses a catalyst material in a lead-acid battery.
The catalyst material comprises a catalyst that promotes a reaction that produces water or water vapor from oxygen and hydrogen, and the container has a membrane-covered opening.
The membrane is characterized in that the oxygen, the hydrogen and the water vapor communicate with each other between the catalyst layer and the outside of the container, and are oriented at an angle of 0 ° or more and 80 ° or less with respect to the direction of gravity. And the container.
[2]
The container according to item [1], wherein the membrane comprises a hydrophobic porous membrane.
[3]
The container according to item [1] or [2], wherein the film comprises porous PTFE.
[4]
The boundary shape of the container is characterized by including at least a part of at least one shape of a cylinder, a cone, a truncated cone, a truncated cone, a polygonal cone, a polygonal cone, or a sphere. The container according to any one of items [1] to [3].
[5]
A lead-acid battery comprising the container according to any one of items [1] to [4].

According to the invention of the present application, a container for accommodating a catalyst layer material in a lead storage battery, which can sufficiently suppress a decrease in the amount of electrolytic solution and does not require redundant measures such as temperature control, and lead using the same. Batteries are provided.
Since the container and the lead storage battery can sufficiently suppress a decrease in the amount of electrolytic solution, the charge / discharge performance and the soundness inside the battery can be maintained for a long period of time.

It is the schematic explaining the mechanism of action which occurs in the catalyst containing container in a lead storage battery. It is a schematic schematic diagram which shows the thing which attached the catalyst accommodating container to the vent cap of the lead storage battery. It is a schematic schematic diagram which shows the catalyst containing container and the vent cap which the orientation angle of a membrane is 0 ° (vertical).

The container, which is one aspect of the present invention, is
A container that houses a catalyst material in a lead-acid battery.
The catalyst material comprises a catalyst that promotes a reaction that produces water or water vapor from oxygen and hydrogen, and the container has a membrane-covered opening.
The membrane communicates the oxygen, the hydrogen and the water vapor between the catalyst material and the outside of the container, and is oriented at an angle of 0 ° to 80 ° with respect to the direction of gravity.

The container is a container for accommodating a catalyst material in a lead storage battery.
Since the electrolytic solution of the lead storage battery is a dilute sulfuric acid aqueous solution, an electrolytic solution (dilute sulfuric acid aqueous solution), sulfuric acid mist, moisture, hydrogen gas and oxygen gas generated by the battery reaction are present in the battery internal space. Hydrogen gas and oxygen gas may be released from the vent of the battery container to the external environment, which leads to a decrease in the amount of electrolyte inside the battery, which in turn leads to deterioration of battery performance and battery health.

The catalyst material contained in the container contains a catalyst that promotes a reaction that produces water or water vapor from oxygen and hydrogen. Therefore, when the hydrogen gas and oxygen gas generated by the battery reaction come into contact with the catalyst material, they are recombined into water or water vapor, and in some cases, the water or water vapor is condensed and recirculated inside the battery. As a result, the decrease of water in the electrolytic solution inside the battery is suppressed. The catalytic material means a material having a catalytic action, and its form is not particularly limited, and may be in a layered form or a powdery form, and may be a sintered body or a compressed material. It may be lumpy like a body, may be carried on a carrier, or may be filled in a frame or the like. Examples of materials having a catalytic action include metal elements such as platinum, palladium, nickel, iron and cobalt.

Further, the container has an opening covered with a membrane, and the membrane communicates the oxygen, the hydrogen and the water vapor between the catalyst material and the outside of the container. These openings and membranes allow the catalyst material contained in the container to come into contact with hydrogen gas and oxygen gas generated by the battery reaction. Further, with this configuration, the catalyst material is housed in the container without leaking from the container.

Further, the film covering the opening is oriented at an angle of 0 ° or more and 80 ° or less with respect to the direction of gravity.

The reason for orienting the film and the background will be described.
Conventionally, as described in Patent Documents 1 and 2, for example, an attempt to suppress a decrease in water in an electrolytic solution by recombining hydrogen gas and oxygen gas generated by a battery reaction using a catalyst in a lead storage battery. Was being done. However, according to the actual confirmation by the present inventors, the decrease in water in the electrolytic solution may not be sufficiently suppressed by the open lead storage, and as a result of investigating the cause, the following mechanism of action is considered. I arrived. This will be described with reference to FIG.
An electrolytic solution (dilute sulfuric acid) exists in the lower part inside the lead-acid battery, and the liquid temperature may reach about 60 ° C. depending on the outside air temperature and the battery reaction. Hydrogen gas, oxygen gas, water vapor, and sulfuric acid mist are generated from the electrolytic solution at this temperature, and they are present in the upper part of the lead storage battery, and the ambient temperature may be about 40 ° C. A container containing the catalyst is attached to the upper part (ceiling part) inside the lead-acid battery.
In such an environment, the following events occur in and around the catalyst.
1. 1. Water condenses on the surface of the membrane of the catalyst containment vessel, forming a layer of liquid (water) on the surface of the membrane.
2. 2. A layer of liquid (water) on the surface of the membrane prevents the inflow of hydrogen gas and oxygen gas (H ₂ / O ₂ ) into the catalyst vessel.
3. 3. Since the inflow of hydrogen gas and oxygen gas (H ₂ / O ₂ ) is reduced and the catalytic reaction is reduced, the catalyst temperature is also reduced.
4. Water condensation occurs inside the catalyst storage container (due to the decrease in catalyst temperature).
5. The catalyst temperature is further lowered (due to condensed water).
6. Due to the difference in the concentration of sulfuric acid between the inside and outside of the catalyst storage container (high outside and low inside), sulfuric acid infiltrates into the inside of the catalyst storage container through the liquid layer on the membrane surface, and the catalyst is poisoned and deteriorated.
7. Due to the deterioration of the catalyst, the reaction of hydrogen gas and oxygen gas (H ₂ / O ₂ ) is not promoted, leading to a decrease in the amount of electrolytic solution.

In view of the above mechanism of action, the present inventors can stop the progress of each step of the mechanism of action by preventing water from condensing on the surface of the membrane of the catalyst containing container, and electrolyze. I came up with the idea that the decrease in the amount of liquid can be suppressed.

In this aspect, the membrane covering the opening of the container containing the catalyst material is oriented at an angle of 0 ° or more and 80 ° or less with respect to the direction of gravity. By orienting the membrane at this angle, even if water is condensed on the surface of the membrane, the condensed water slides down in the direction of gravity, so that a layer of liquid (water) is formed on the surface of the membrane. Can be prevented. As a result, the subsequent steps of the series of action mechanisms do not proceed. As a result, deterioration of the catalyst does not occur, and a decrease in the amount of electrolytic solution can be sufficiently suppressed. Further, this aspect is advantageous in that it does not require redundant work such as temperature control and a device for that purpose.

The present inventors repeated various trials and errors to change the shape and structure of the battery container in order to find a method for improving the performance of the catalyst in the lead-acid battery until the idea of this aspect was obtained. Specifically, the catalyst device (catalyst storage container) is arranged at a position different from the conventional one, the amount of catalyst in the catalyst device is increased from the conventional one, and the material, size, and configuration of the membrane covering the opening of the catalyst device are provided. Etc., and the orientation (orientation) of the catalyst device was adjusted. In practice, candidates for these improved methods are often constrained by the shape and structure of the battery container and are not easily feasible. In particular, it is easy for those skilled in the art to adjust the orientation of the catalyst device, which is not preferable because it has a large effect on the depth of battery assembly, and that the catalyst device is preferably arranged flat. Understand. That is, it should be noted that motivation for those skilled in the art to adjust the orientation of the catalyst device is not easily obtained.
Nonetheless, the present inventors have actually performed the above trial and error, and surprisingly, adjusting the orientation of the catalyst device is most effective in reducing the amount of electrolyte. I found that.

The effect of the present invention can be confirmed by the following simple method. FIG. 2 shows a lead-acid battery with a container containing a catalyst attached to the sealing plug. In FIG. 2A, the membrane of the catalyst container is horizontally oriented (at an angle of 90 ° with respect to the direction of gravity) and installed in the lead-acid battery. In the one shown in FIG. 2B (Vertical design), the membrane of the catalyst containing container is vertically oriented (at an angle of 0 ° with respect to the direction of gravity) and installed in the lead-acid battery. A 14.4V lead-acid battery equipped with these catalyst containing containers was installed in a hot water bath (water bath) for 12 weeks to maintain the temperature of the electrolytic solution at 60 ° C., and the amount of decrease in the electrolytic solution inside the battery was reduced. It was measured. The height of the hot water in the hot water bath was adjusted so that the height of the electrolytic solution inside the lead-acid battery was almost the same. This is to promote the condensation of water in the membrane of the catalyst accommodating container by keeping the ambient temperature above the electrolytic solution, in other words, the ambient temperature of the catalyst accommodating container, as low as possible while maintaining only the electrolytic solution at 60 ° C. is there. As a control, a lead-acid battery without a catalyst container (with only a vent cap attached) was also prepared, and the amount of decrease in the electrolytic solution was measured.

Furthermore, for reference, some of the trial and error performed by the present inventors will be introduced. The first trial and error is "increasing the amount of catalyst", which is the above-mentioned horizontal catalyst container in which the packing density of the catalyst material is increased five times. It is expected that a large amount of catalyst material will increase the heat of reaction and suppress the condensation of water. Another trial and error is the "double membrane structure", which is the above-mentioned horizontal catalyst storage container in which another membrane is placed on the original membrane. It is expected that the double membrane structure will prevent the condensed water from blocking the membrane surface.

As a result of the above simple test, in the control non-catalyst lead-acid battery, the amount of decrease in the electrolytic solution after 12 weeks was about 650 g. In a lead-acid battery in which the membrane of the catalyst storage container was installed horizontally (Flat design), the test was interrupted because the catalyst deteriorated in about 2 weeks and the catalytic reaction did not proceed. After that, the amount of the electrolytic solution is considered to decrease as in the case of no control catalyst, and the amount of decrease of the electrolytic solution after 12 weeks is considered to be about 550 g. On the other hand, in the lead-acid battery in which the membrane of the catalyst container was vertically installed (Vertical design), no deterioration of the catalyst was observed, and the amount of decrease in the electrolytic solution after 12 weeks was about 250 g. In addition, in the reference "catalyst amount increase" and "double membrane structure", the test was interrupted because the catalyst deteriorated in about 4 weeks and the catalytic reaction did not proceed. The amount of decrease in the electrolytic solution after 12 weeks is considered to be about 500 g. As described above, it can be confirmed that the reduction amount of the electrolytic solution can be sufficiently suppressed in the catalyst container according to one aspect of the present invention.

The orientation direction of the membrane of the catalyst containing container is 0 ° or more and 80 ° or less with respect to the direction of gravity. The orientation direction is the direction of gravity, in other words, the closer it is to 0 ° or closer, the more easily the condensed water slides off the membrane, which is advantageous. If the orientation direction of the membrane exceeds 80 ° with respect to the direction of gravity, condensed water may not slide off the membrane and a layer of liquid (water) may be formed on the surface of the membrane. In that case, the amount of electrolyte solution It may not be possible to sufficiently suppress the decrease in. Therefore, the orientation direction of the film is 0 ° or more and 80 ° or less with respect to the direction of gravity. The angle may be appropriately adjusted within the above range according to the space for mounting the catalyst storage container and the shape of the surrounding structure.

In one aspect of the present invention, the membrane of the catalyst containing container may include a hydrophobic porous membrane.
Since the hydrophobic porous film is hydrophobic (water repellent), it is possible to prevent the sulfuric acid mist and the electrolytic solution (dilute sulfuric acid aqueous solution) from coming into direct contact with the catalyst material in the catalyst container, and the catalyst. Life can be extended.

In one aspect of the present invention, the film may also contain porous PTFE.
The material of the film is not particularly limited as long as it can permeate oxygen, hydrogen and water vapor, but a material that does not react with other materials inside the battery, such as sulfate, is preferable, and polyethylene (PE). ), Polypropylene (PP), polytetrafluoroethylene (PTFE) and the like, and woven fabrics, non-woven fabrics, knitted fabrics or porous films thereof may be used. The hydrophobic porous membrane may be porous polytetrafluoroethylene (PTFE). Polytetrafluoroethylene has excellent properties such as hydrophobicity, chemical resistance, ultraviolet ray resistance, oxidation resistance, and heat resistance, and is suitable as a material for constituting a battery. Further, a porous membrane can be easily obtained by stretching polytetrafluoroethylene or the like.

In one aspect of the invention, at least part of the boundary shape of the catalyst containment vessel is at least one of the following shapes: a cylinder, a cone, a truncated cone, a polygonal column, a polygonal cone, a truncated cone, or a sphere. It may include a part.
The boundary shape (or outer shape) of the catalyst containing container is not particularly limited as long as the film is oriented at a predetermined angle, and may include various shapes. From the viewpoint of easily accommodating the catalyst material, the shape of a cylinder or a polygonal column may be selected. From the viewpoint of increasing the reaction efficiency of the catalyst material, a sphere having a large surface area per unit volume may be selected. In addition, from the viewpoint that the catalyst container can be easily installed inside the lead-acid battery, especially in the ceiling, the shape of a protruding cone, a truncated cone, a polygonal cone, or a polygonal cone may be selected for a part of the container. Good. Further, various shapes can be appropriately combined according to the intended use. The container may be a cartridge type.

In one aspect of the present invention, a lead storage battery including the above-mentioned catalyst storage container is provided.
In the lead storage battery including the catalyst accommodating container described above, the decrease in the amount of electrolytic solution can be sufficiently suppressed, and there is no need for redundant measures such as temperature control. Therefore, the charge / discharge performance and the soundness inside the battery can be maintained for a long period of time.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not construed as being limited to the following examples.

A container containing the catalyst was prepared by the following procedure. A resin cylinder was prepared, and a disk of the same material as the cylinder (side surface) was welded to the bottom of the cylinder to seal the bottom of the cylinder. The inside of the cylinder was filled with a catalyst material that promotes the reaction of producing water or water vapor from oxygen and hydrogen, and the upper part (opening) of the cylinder was covered with membranes of various materials shown in Table 2. As a control, only a container not filled with a catalyst material was prepared.
The prepared catalyst storage container was attached to the upper part (ceiling part) of the lead storage battery so that the film had an orientation angle (angle of the film with respect to the direction of gravity) shown in Table 2. Specifically, the catalyst container was attached to the vent cap to adjust the orientation angle, and the vent cap was attached to the ceiling of the lead-acid battery. FIG. 3 shows an example of a catalyst container and a vent cap in which the orientation angle of the membrane is 0 ° (vertical). As the lead storage battery, a commercially available LN2 type EFB (ENJ375LN2-IS manufactured by GS Yuasa) was used.

Lead-acid batteries with catalyst storage containers are installed in hot water baths (water baths) for 12 weeks to maintain the temperature of the electrolyte at 60 ° C, and the total weight of the batteries is measured to measure the electrolyte inside the batteries. The amount of decrease was measured. The height of the hot water in the hot water bath was adjusted so that the height of the electrolytic solution inside the lead-acid battery was almost the same. This is to promote the condensation of water in the membrane of the catalyst accommodating container by keeping the ambient temperature above the electrolytic solution, in other words, the ambient temperature of the catalyst accommodating container, as low as possible while maintaining only the electrolytic solution at 60 ° C. is there. In addition, as a control, a lead storage battery equipped with a container not filled with a catalyst material was also prepared, and the amount of decrease in the electrolytic solution was measured. The results are shown in Table 2.

From the above results, in the control non-catalyst lead-acid battery, the amount of decrease in the electrolytic solution after 12 weeks was about 400 g.
When the membrane of the catalyst container is oriented at an angle within the range of the present invention, the amount of decrease in the electrolytic solution is about 50 to 200 g even after 12 weeks, which is significantly reduced as compared with the control, and the catalyst is contained. The atmosphere of the container and its surroundings was maintained at about 40 ° C. (particularly, redundant operations such as heating were not performed for temperature control). From these facts, it was suggested that the catalytic reaction proceeded stably.
On the other hand, when the film was oriented at an angle of 90 °, that is, horizontally, the amount of decrease in the electrolytic solution was about 360 g, which was not sufficiently reduced as compared with the control. In this comparative example, water is condensed on the surface of the membrane, and since the membrane is horizontal, the condensed water does not slide down, and a layer of liquid (water) is formed on the surface of the membrane to promote the catalytic reaction. However, it was suggested that the catalyst eventually deteriorated.

10 Vent cap for lead-acid battery 20 Catalyst storage container 30 Catalyst material 40 Membrane 50 Holder

Claims (5)

A container that houses a catalyst material in a lead-acid battery.
The catalyst material comprises a catalyst that promotes a reaction that produces water or water vapor from oxygen and hydrogen, and the container has a membrane-covered opening.
The membrane is characterized in that the oxygen, the hydrogen and the water vapor communicate with each other between the catalyst material and the outside of the container, and are oriented at an angle of 0 ° or more and 80 ° or less with respect to the direction of gravity. And the container. The container according to claim 1, wherein the membrane comprises a hydrophobic porous membrane. The container according to claim 1 or 2, wherein the film comprises porous PTFE. The boundary shape of the container is characterized by including at least a part of at least one shape of a cylinder, a cone, a truncated cone, a truncated cone, a polygonal cone, a polygonal cone, or a sphere. The container according to any one of claims 1 to 3. A lead-acid battery comprising the container according to any one of claims 1 to 4.