JP6965533B2 - Lead-acid battery - Google Patents

Description

The present invention relates to a lead storage battery.

Lead-acid batteries are used for various purposes such as in-vehicle use and industrial use. A lead-acid battery has a electrode plate group including a positive electrode plate and a negative electrode plate, an electrolytic solution in which the electrode plate group is immersed, and a cell chamber for accommodating the electrode plate group and the electrolytic solution, and has an opening at the top. It is provided with a tank and a lid for sealing the opening of the battery case. The battery case and the lid are molded bodies containing synthetic resin as a main component. A pair of tubular bushings are fixed to the lid by insert molding so as to penetrate the lid. The bushing is made of lead or a lead alloy. A positive electrode column conducting with the positive electrode plate is inserted in the positive electrode bushing, and a negative electrode column conducting with the negative electrode plate is inserted in the negative electrode bushing. An external terminal is formed by welding the upper end of each pole and the upper end of the bushing.

If the lead-acid battery is used for a long period of time, the adhesion between the bushing and the synthetic resin may decrease, and the electrolytic solution may seep out from the periphery of the external terminal.

Therefore, Patent Document 1 proposes to apply an acid-resistant resin to the facing surface of the bushing facing the synthetic resin portion to make it a mirror surface. Epoxy resin is used as the acid resistant resin.

Further, by forming an annular flange portion on the outer surface of the bushing, the movement path of the electrolytic solution is lengthened (Patent Document 2).

JP-A-2010-3446 Japanese Unexamined Patent Publication No. 2008-300139

Epoxy resins are known to have excellent adhesiveness to synthetic resins and lead, and also to have excellent durability. Therefore, Patent Document 1 also proposes to use an epoxy resin as the acid resistant resin. However, the epoxy resin is inconvenient to handle, and it is considered that it is difficult to reduce the manufacturing cost of the lead storage battery by using the epoxy resin for the external terminal.

In view of the above, one aspect of the present invention has an electrode plate group including a positive electrode plate and a negative electrode plate, an electrolytic solution containing sulfuric acid, and an opening, and houses the electrode plate group and the electrolytic solution. An electric tank having a cell chamber and a lid for sealing the opening of the electric tank are provided, and the lid includes a molded body containing the first resin and a tubular positive electrode bushing inserted into the molded body. A tubular negative electrode bushing inserted into the molded body is provided, and at least a second resin different from the first resin is interposed between the positive electrode bushing and the first resin, and the second resin is interposed. The present invention relates to a lead storage battery in which the resin contains an acrylic resin.

According to the present invention, it is possible to reduce the exudation of the electrolytic solution from the periphery of the external terminal while reducing the manufacturing cost of the lead storage battery.

It is a partially cutaway perspective view which shows the appearance and the internal structure of the lead storage battery which concerns on embodiment of this invention. It is sectional drawing of the tubular bushing fixed to the lid by insert molding. It is an enlarged view of the cross section perpendicular to the circumferential direction of the flange-shaped rib formed on the peripheral surface of a bushing along the circumferential direction. It is sectional drawing which shows the 1st modification of a tubular bushing. It is sectional drawing which shows the 2nd modification of the tubular bushing. It is sectional drawing which shows the 3rd modification of the tubular bushing.

One aspect of the present invention has a electrode plate group including a positive electrode plate and a negative electrode plate, an electrolytic solution containing sulfuric acid, and an opening, and has a cell chamber for accommodating the electrode plate group and the electrolytic solution. A battery case and a lid for sealing the opening of the battery bed are provided, and the lid includes a molded body containing the first resin, a tubular positive electrode bushing inserted into the molded body, and the molded body. A tubular negative electrode bushing inserted into the is provided, and at least a second resin different from the first resin is interposed between the positive electrode bushing and the first resin, and the second resin is acrylic. Regarding lead-acid batteries containing based resins. Since the second resin contains an acrylic resin, the manufacturing cost of the lead storage battery can be reduced, and the exudation of the electrolytic solution from the periphery of the external terminal can be reduced.

The acrylic resin is preferably a cured product of a photocurable acrylic resin. Since the photocurable acrylic resin cures quickly, a lead storage battery can be manufactured more efficiently.

At least one rib may be provided on the peripheral surface of the positive electrode bushing along the circumferential direction of the positive electrode bushing. Even when the electrolytic solution crawls up between the bushing and the molded product due to the ribs, the movement path of the electrolytic solution becomes long, and it becomes easy to reduce the exudation of the electrolytic solution.

The rib has a pair of side surfaces rising from the root of the rib and a top continuous with the side surface, so that the width of the rib increases from the top toward the root. It is preferable to have an inclination. As a result, the entire resin coating film of the photocurable acrylic resin applied to the peripheral surface of the bushing is easily irradiated with light.

The acute angle θ formed by the protruding direction of the rib and the pair of side surfaces may be, for example, 0.5 ° or more and 60 ° or less. When the angle θ is in the above range, the efficiency of irradiating the side surface of the rib with light is sufficiently improved.

The peripheral surface of the positive electrode bushing may be smooth. In this case, the efficiency of irradiating the entire resin coating film of the photocurable acrylic resin with light is further improved.

Hereinafter, embodiments of the present invention will be further described.
The lead-acid battery according to the embodiment of the present invention has an electrode plate group including a positive electrode plate and a negative electrode plate, an electrolytic solution containing sulfuric acid in which the electrode plate group is immersed, and an opening, and the electrode plate group and the electrolytic solution. It is provided with an electric tank having a cell chamber for storing and a lid for sealing the opening of the electric tank. The lid is a molded product containing the first resin.

The first resin is not particularly limited, but is a thermoplastic resin such as an acrylonitrile butadiene styrene copolymer resin (ABS resin) and a polypropylene resin (PP resin). The molded product may contain components other than the first resin. Examples of other components include fillers, plasticizers, and antioxidants. The first resin may be a mixture or composite of a plurality of resin components or a polymer alloy.

The lid includes a tubular positive electrode bushing and a tubular negative electrode bushing, respectively, which are inserted into a molded body containing the first resin. Here, at least between the positive electrode bushing and the first resin or the molded product, a second resin different from the first resin is interposed, and the second resin contains an acrylic resin.

Epoxy resins with excellent durability are usually thermosetting and need to be cured by heating for a considerable period of time. In addition, epoxy resin has low viscosity stability and is inconvenient to handle, so that the amount of waste tends to be large. Therefore, when an epoxy resin is used as the second resin, it becomes difficult to reduce the manufacturing cost of the lead storage battery.

Acrylic resins are generally considered to be inferior in durability and weather resistance to epoxy resins. However, according to the study of the inventor of the present invention, the acrylic resin is more excellent in adhesion to the lead or lead alloy constituting the bushing than expected by those skilled in the art, and also adheres to the first resin constituting the lid. It turned out to be excellent in sex. Further, by interposing an acrylic resin between the molded body containing the first resin and the bushing, it is possible to reduce the exudation of the electrolytic solution from the periphery of the external terminal to the same extent as or more than the epoxy resin. It has been found.

Next, the advantages of using the acrylic resin will be described. First, since the acrylic resin cures in a shorter time than the epoxy resin, the manufacturing tact of the lead storage battery can be significantly shortened. Among them, the photocurable acrylic resin rapidly undergoes a curing reaction when irradiated with light. It often takes about 60 minutes to cure the epoxy resin, whereas most acrylic resins cure in 1 to 2 minutes, and the curing is completed within 5 to 10 minutes at the longest. ..

Further, since the acrylic resin has high viscosity stability and is excellent in handleability as compared with the epoxy resin, it is easy to manage and the amount of waste can be significantly reduced. Further, the frequency of use of the solvent for cleaning the equipment used when applying the acrylic resin to the bushing can be reduced.

Exudation of the electrolytic solution from the periphery of the external terminal tends to occur on the positive electrode plate side where the bushing is likely to be corroded. Therefore, it is necessary to interpose a second resin at least between the positive electrode bushing and the first resin or the molded product. Further, from the viewpoint of enhancing the reliability of the lead storage battery, it is preferable to interpose the second resin between the negative electrode bushing and the first resin or the molded body as in the case of the positive electrode plate side. In either case, it is preferable to use an acrylic resin as the second resin.

The acrylic resin is a resin having a plurality of acryloyl groups or methacryloyl groups (hereinafter, collectively referred to as (meth) acryloyl groups) bonded to the basic skeleton, and usually contains a unit of an acrylic acid ester or a methacrylic acid ester. There is. Such a unit is, for example, an ester of alcohol and (meth) acrylic acid, and the content thereof in the acrylic resin is not particularly limited, but may be contained, for example, 5% by mass or more and 15% by mass or more. preferable. The polymerization of the (meth) acryloyl group promotes the curing of the acrylic resin.

Acrylic resins include modified acrylic resins into which various molecular chains have been introduced. From the viewpoint of obtaining a faster curing rate, a radically polymerizable acrylic resin is preferable, and for example, epoxy-modified acrylate, urethane-modified acrylate, silicone-modified acrylate, acrylic-modified acrylate and the like can be used. Of these, epoxy-modified acrylates and urethane-modified acrylates are preferable because they exhibit excellent adhesiveness.

Among the acrylic resins, a photocurable acrylic resin is preferable because it cures quickly, and for example, a UV curable acrylic resin is preferable. The UV curable acrylic resin usually contains a reaction initiator (UV initiator) that is activated by irradiation with UV light. As the UV initiator, an azo compound, a peroxide and the like are used. Since these partially remain in the second resin after curing, it is possible to identify that they are UV-curable acrylic resins.

When a photocurable acrylic resin is used, after applying the photocurable acrylic resin to the peripheral surface of the bushing, the peripheral surface of the bushing having the resin coating film is irradiated with light or UV light to cure the resin coating film. Just do it. That is, the acrylic resin contained in the second resin can be, for example, a cured product of a photocurable acrylic resin. The irradiation time of light or UV light may be appropriately selected depending on the energy of the irradiation light. As a result, a cured film of the second resin containing the acrylic resin is formed on the peripheral surface of the bushing. The thickness of the cured film of the second resin may be, for example, 0.1 μm to 1000 μm, preferably 15 μm to 300 μm. After that, if a bushing having a cured film of the second resin, a molded body containing the first resin, and a lid having a positive electrode bushing and a negative electrode bushing are formed by insert molding using the raw material and the mold of the molded body. good.

The peripheral surface of the tubular bushing may be smooth (curved surface without unevenness), but ribs or protrusions (for example, collar-shaped or annular ribs) may be formed on the peripheral surface of the bushing along the circumferential direction. By providing at least one such rib on the peripheral surface of the bushing, even when the electrolytic solution crawls between the bushing and the molded body (or the first resin), the movement path of the electrolytic solution becomes long, so that the outside It becomes easy to reduce the exudation of the electrolytic solution from the periphery of the terminal. Again, it is preferable that at least one rib is provided on the peripheral surface of the positive electrode bushing, and it is more preferable that at least one rib is provided on the peripheral surface of the negative electrode bushing.

The number of ribs formed on the peripheral surface of the bushing is not particularly limited, and the larger the number of ribs, the easier it is to reduce the exudation of the electrolytic solution. However, when the number of ribs is large, the shape of the bushing becomes complicated and it takes time to manufacture the bushing. Therefore, the number of ribs is preferably 1 to 5.

The shape of the rib preferably has a pair of side surfaces rising from the root of the rib and a top continuous with the side surface. As a result, the movement path of the electrolytic solution when the electrolytic solution crawls up can be made as long as possible. In order to make the movement path of the electrolytic solution the longest, it is desirable to form a pair of side surfaces so as to rise vertically from the peripheral surface of the bushing. Therefore, normally, the angle θ formed by the protruding direction of the rib and the side surface of the rib is set to less than 0.5 °.

On the other hand, when the acrylic resin is a photocurable acrylic resin, it is preferable that the pair of side surfaces of the rib have a sufficient inclination so that the width of the rib increases from the top to the root. As a result, when the resin coating film of the photocurable acrylic resin applied to the peripheral surface of the bushing is cured, when light is incident so as to intersect the peripheral surface of the bushing, the light is emitted to the entire resin coating film. It becomes easy to be irradiated. Therefore, a part of the acrylic resin is less likely to remain in the uncured state, and the adhesiveness between the acrylic resin and the bushing or the first resin is improved.

The acute angle θ formed by the protruding direction of the rib and the pair of side surfaces is preferably 0.5 ° or more and 60 ° or less, and more preferably 1 ° or more and 45 ° or less. Here, the protruding direction of the rib is a direction in which the rib rises vertically from the peripheral surface of the bushing. By setting the angle θ in the above range, the efficiency of irradiating the side surface of the rib with light is sufficiently improved, and the curing of the photocurable acrylic resin proceeds more quickly. In addition, the movement path of the electrolytic solution can be ensured to be sufficiently long. The angle θ may be constant or variable in the region from the root to the top of the rib. When the angle θ changes, the acute angle θ formed by the protruding direction of the rib and the tangent to the side surface may be measured at a position corresponding to the height of half of the rib.

FIG. 1 shows a perspective view in which a part of an example of a lead storage battery according to an embodiment of the present invention is cut out. The lead-acid battery 1 includes an electric tank 12 that houses a electrode plate group 11 and an electrolytic solution (not shown). The inside of the electric tank 12 is partitioned into a plurality of cell chambers 14 by a partition wall 13. In each cell chamber 14, one electrode plate group 11 is stored. The opening of the battery case 12 is sealed with a lid 15 provided with a positive electrode bushing 16 and a negative electrode bushing 17. The lid 15 is provided with a liquid spout 18 for each cell chamber 14. At the time of refilling water, the liquid spout 18 is removed and the refilling liquid is replenished.

The positive electrode bushing 16 and the negative electrode bushing 17 are each tubular, and are fixed to the lid 15 by insert molding so as to penetrate the lid 15. The upper end of the positive electrode column 7 conducting with the positive electrode plate 2 is inserted into the hollow of the positive electrode bushing 16, and the upper end of the negative electrode column 9 conducting with the negative electrode plate 3 is inserted into the hollow of the negative electrode bushing 17. Each bushing is made of lead or a lead alloy, and the positive electrode column 7 and the negative electrode column 9 are also made of lead or a lead alloy. The upper end of the positive electrode column 7 is welded to the upper end of the positive electrode bushing 16. As a result, an external positive electrode terminal is formed. The upper end of the negative electrode column 9 is welded to the upper end of the negative electrode bushing 17. As a result, an external negative electrode terminal is formed.

The electrode plate group 11 is formed by laminating a plurality of positive electrode plates 2 and a plurality of negative electrode plates 3 via a separator 4. Here, the bag-shaped separator 4 accommodating the negative electrode plate 3 is shown, but the form of the separator is not particularly limited. In the cell chamber 14 located at one end of the battery case 12, the positive electrode shelf 5 connecting the plurality of positive electrode plates 2 in parallel is connected to the positive electrode column 7, and the negative electrode shelf 6 connecting the plurality of negative electrode plates 3 in parallel penetrates. It is connected to the connecting body 8. In the cell chamber 14 located at the other end of the battery case 12, the negative electrode column 9 is connected to the negative electrode shelf 6, and the through connecting body 8 is connected to the positive electrode shelf 5. Each through-connecting body 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plates 11 of the adjacent cell chambers 14 in series.

The positive electrode plate 2 may be a paste type or a clad type, but in the illustrated example, a paste type positive electrode plate is shown. The positive electrode plate 2 includes a positive electrode current collector and a positive electrode material held by the positive electrode current collector. The negative electrode plate 3 includes a negative electrode current collector and a negative electrode material held by the negative electrode current collector. Each current collector may be formed by casting lead or a lead alloy, or may be formed by expanding or punching a lead or lead alloy sheet. A non-woven fabric sheet, a microporous film, or the like is used for the separator 4.

The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary. The specific gravity of the electrolytic solution in a fully charged lead-acid battery at 20 ° C. is, for example, 1.1 to 1.35 g / cm ³ , and preferably 1.2 to 1.35 g / cm ^3.

FIG. 2 shows a cross-sectional view of the positive electrode bushing 16 fixed to the lid 15. FIG. 2 corresponds to a cross-sectional view taken along the line II-II of FIG. FIG. 3 shows an enlarged view of a cross section of a collar-shaped rib formed on the peripheral surface of the positive electrode bushing 16 along the circumferential direction and perpendicular to the circumferential direction. FIG. 3 corresponds to an enlarged view of the region X surrounded by the broken line shown in FIG. The structure of the negative electrode bushing 17 is the same.

A plurality of flange-shaped ribs 161 are provided on the peripheral surface of the positive electrode bushing 16 along the circumferential direction. The shape of the cross section perpendicular to the circumferential direction of the rib 161 has a pair of side surfaces 161S rising from the root of the rib 161 and a top portion 161T continuous with the side surface 161S, and has a shape close to a trapezoid. That is, the pair of side surfaces 161S of the ribs 161 have an inclination such that the width of the ribs 161 increases from the top portion 161T toward the root. Therefore, when the resin coating film 20 of the photocurable acrylic resin applied to the peripheral surface of the bushing 16 is cured, the efficiency of irradiating the side surface 161S with light is improved. In FIG. 3, the shape of the cross section perpendicular to the circumferential direction of the rib 161 is close to a trapezoid, but as in the first modification shown in FIG. 4A, the shape of the rib top is close to a pointed triangle. A shape having one or more steps on the side surface of the rib may be used as in the second modification shown in FIG. 4B. Further, the peripheral surface of the rib may be smooth as in the third modification shown in FIG. 4C. Smoothing refers to a case where the maximum height roughness Rz of the surface is 200 μm or less.

The acute angle θ formed by the protruding direction D of the rib 161 and the pair of side surfaces 161S is approximately 13 ° in the illustrated example, but is not limited to this. Further, the angle θ is constant in the region from the root of the rib 161 to the top 161T, but is not limited to this. In either case, the angle θ may be measured at a position corresponding to a height H / 2 which is half the height of the rib 161. By appropriately increasing the angle θ as described above, not only the efficiency of irradiating the side surface 161S with light is improved, but also the movement path of the electrolytic solution that crawls up the bushing 16 is secured sufficiently long.

Hereinafter, embodiments of the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<< Example 1 >>
A cylindrical bushing having a smooth peripheral surface without ribs as shown in FIG. 4C was formed from a lead alloy by casting. The outer diameter R of the bushing was approximately 17 mm, and the height L was 17.5 mm. A UV-curable acrylic resin was applied to the peripheral surface of the obtained bushing ^{so as to be 32 mg per 1 cm 2 of the} peripheral surface area to form a resin coating film having a thickness of 200 μm.

Next, the peripheral surface of the bushing on which the resin coating film of the UV curable acrylic resin was formed was irradiated with a predetermined amount of light from a direction perpendicular to the peripheral surface to cure the coating film. At this time, an LED lamp having an output of 200 mW and an illuminance of 2200 mW / cm ^{2 was used as the light source.}

Next, as shown in FIG. 2, a lid in which the molded body containing the first resin (ABS resin) and the bushing were integrated was produced by insert molding. At this time, the peripheral surface of the bushing having the cured film of the acrylic resin was sealed with ABS resin. Then, a part of the plate-shaped region sealing the bushing was cut out from the lid together with the bushing to obtain a test sample including a small piece of the molded product containing the first resin and a bushing inserted into the small piece.

A plate-shaped cathode (counter electrode) is immersed in a tray into which an aqueous sulfuric acid solution (electrolyte solution) having a specific density of 1.280 g / cm ^{3 is poured, and a test sample is placed on the plate-shaped cathode (counter electrode) via a porous diaphragm.} Placed. At this time, the boundary B shown in FIG. 2 was arranged below and immersed in the electrolytic solution. The boundary A shown in FIG. 2 was placed above the liquid level of the electrolytic solution, and was completely shielded from the electrolytic solution by surrounding the bushing with a polypropylene cup so that the electrolytic solution could not contact the boundary A. .. Then, the bushing portion of the test sample was connected to the anode of the power supply, and a current of 5 A was continuously applied between the anode and the cathode in an environment of 20 ° C. for 5 hours.

After that, when the bushing was separated from the test sample and the creeping distance of the electrolytic solution from the boundary B was confirmed using Congo Red as an indicator, no creeping of the electrolytic solution was confirmed and no exudation of the electrolytic solution occurred. I was able to confirm that.

<< Example 2 >>
The same evaluation as in Example 1 was performed except that four brim-shaped ribs were provided on the peripheral surface of the bushing. As shown in FIG. 4A, the shape of the cross section perpendicular to the circumferential direction of the rib is a shape close to an equilateral triangle (θ = 30 °), and the height H of the rib is 1.2 mm. When the creep-up distance of the electrolytic solution from the boundary B was confirmed, the creep-up of the electrolytic solution was not confirmed, and it was confirmed that the electrolytic solution did not exude. When the peripheral surface of the bushing was observed, the uncured component of the acrylic resin could not be confirmed, and it was presumed that the curing had progressed sufficiently. Since the side surface of the rib has an inclination, it is considered that the UV curable acrylic resin is sufficiently irradiated with UV light.

<< Comparative Example 1 >>
The same evaluation as in Example 1 was performed except that a UV curable urethane resin was used instead of the UV curable acrylic resin. However, despite sufficient UV irradiation, the urethane resin was easily peeled off from the peripheral surface of the bushing, so the evaluation was stopped at that point.

<< Comparative Example 2 >>
Four brim-shaped ribs were provided on the peripheral surface of the bushing. The shape of the cross section perpendicular to the circumferential direction of the rib was a quadrangle (θ = 0 °), and the height H of the rib was 1.2 mm. A two-component epoxy resin was used instead of the UV-curable acrylic resin, and the resin coating film was heated at 70 ° C. for 2 hours instead of irradiating with UV light. Other than the above, the same evaluation as in Example 1 was performed. When the creep-up distance of the electrolytic solution from the boundary B was confirmed, the creep-up of the electrolytic solution was not confirmed, and it was confirmed that the electrolytic solution did not exude. However, since it took the above time to cure the epoxy resin, it is considered that the manufacturing tact of the lead storage battery becomes considerably long at the manufacturing site.

1 lead-acid battery, 2 positive electrode plate, 3 negative electrode plate, 4 separator, 5 positive electrode shelf, 6 negative electrode shelf, 7 positive electrode column, 8 through connection, 9 negative electrode column, 11 electrode plate group, 12 battery case, 13 partition wall, 14 cells Room, 15 lids, 16 positive electrode bushing, 17 negative electrode bushing, 18 liquid spout

Claims (5)

A group of electrode plates including a positive electrode plate and a negative electrode plate,
Electrolyte containing sulfuric acid and
An electric tank having an opening and a cell chamber for accommodating the electrode plate group and the electrolytic solution, and
A lid for sealing the opening of the battery case is provided.
The lid includes a molded body containing the first resin, and a tubular positive electrode bushing and a tubular negative electrode bushing inserted into the molded body, respectively.
A second resin different from the first resin is interposed between at least the positive electrode bushing and the first resin.
The second resin contains an acrylic resin and contains
A lead-acid battery in which the acrylic resin is a cured product of a photocurable acrylic resin. The lead-acid battery according to claim 1, wherein at least one rib is provided on the peripheral surface of the positive electrode bushing along the circumferential direction of the positive electrode bushing. The rib has a pair of side surfaces rising from the root of the rib and a top continuous with the side surface.
The lead-acid battery according to claim 2 , wherein the pair of side surfaces are inclined so that the width of the ribs increases from the top to the root. The lead-acid battery according to claim 3, wherein the acute angle θ formed by the direction in which the rib rises vertically from the peripheral surface of the positive electrode bushing and the pair of side surfaces is 0.5 ° or more and 60 ° or less. .. The lead-acid battery according to claim 1, wherein the peripheral surface of the positive electrode bushing is smooth.

Images