JP2008034167A - Lead acid storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead acid storage battery superior in maintenance-free performance by suppressing reduction of an electrolytic liquid in the lead acid storage battery for automobile. <P>SOLUTION: In the liquid type lead acid storage battery using a Pb-Ca system alloy for a positive electrode grid and a negative electrode grid, a valve 21 is arranged in a liquid plug 10, and a sheet to cover an exhaust port 11 of the liquid plug is pasted on a lid 8 by an adhesive or the like. As a result, a gas exhaust path is formed between the sheet and the lid. With this structure, the lead acid storage battery remarkably suppressed in reduction of liquid of the moisture in the electrolytic liquid and having high maintenance-free performance can be provided. Furthermore, by peeling off the sheet, make-up of water can be made from the liquid plug hole to enable to use the lead acid storage battery for a long period. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lead-acid battery.

  Lead-acid batteries are used for various purposes such as vehicle engine starting and backup power supply. Among them, the start lead-acid battery supplies power to various electric and electronic devices mounted on the vehicle as well as power to the engine start cell motor. After the engine is started, the battery is charged by the alternator. Here, the output voltage and output current of the alternator are set so that charging and discharging are balanced and the SOC of the battery is maintained at approximately 100%.

  In most cases, the starting lead-acid battery is installed in the engine room. Therefore, the operating temperature of the lead storage battery is as high as 40 ° C. or higher, and 80 ° C., and is used in an overcharged state.

  When the lead storage battery is overcharged, the water in the electrolytic solution is decomposed into oxygen gas and hydrogen gas and discharged outside the battery, so that the water in the electrolytic solution is reduced. As a result, the sulfuric acid concentration in the electrolytic solution increases, and the capacity decreases due to corrosion deterioration of the positive electrode plate. In addition, when the electrolytic solution surface is lowered and the electrode plate is exposed from the electrolytic solution, there arises a problem that the discharge capacity is drastically reduced and the connecting portion between the negative electrode plate and the strap or the strap itself is corroded.

  As described above, especially in a lead storage battery for start-up used in a high-temperature atmosphere, suppression of moisture reduction (hereinafter referred to as “liquid reduction”) in the electrolytic solution is a serious problem. For the purpose of suppressing liquid reduction in this lead storage battery, Pb—Ca-based alloys have been adopted for both the positive and negative grids. Since the Pb—Ca alloy has a higher hydrogen overvoltage than the conventionally used Pb—Sb alloys, it is possible to suppress liquid reduction due to water electrolysis.

  On the other hand, the cause of liquid reduction in lead-acid batteries is due to the generation of gas due to the electrolysis of water, as described above, and the fact that water vapor generated by the evaporation of water in the electrolyte is simply released outside the battery. There is. By using a Pb—Ca-based alloy for the positive electrode / negative electrode lattice, the former liquid reduction due to the electrolysis of water can be suppressed, but it cannot be said to be a particularly effective means for suppressing water evaporation.

  In order to suppress such liquid reduction due to moisture evaporation, a maze-like exhaust path is provided in the battery lid, and water vapor condenses on the inner wall of the exhaust path while water vapor diffuses in the exhaust path. It is known that water is refluxed to a cell (see, for example, Patent Document 1).

  Patent Document 2 shows that by sticking a seal that covers the exhaust port of the liquid plug attached to the battery cover to the battery cover, the dissipation of water vapor through the exhaust port to the outside of the battery is suppressed. ing.

  The method of providing the maze structure in the battery lid as shown in Patent Document 1 requires a resin molded part different from the battery lid to obtain the maze structure, and this resin molding in the battery assembly process. Since a process of joining the parts to the battery lid by heat welding is required, the manufacturing cost of the battery has to be higher.

In addition, in the lead storage battery having such a structure, it is impossible to refill water when the electrolytic solution level is lowered. Therefore, when the electrolytic solution surface is lowered from a specified position, the lead storage battery has to be replaced. . In this respect, the method of covering the exhaust port of the liquid spigot with a seal as shown in Patent Document 2 allows the water replenishment work because the seal is once peeled off and the liquid spigot can be detached. However, the liquid reduction suppression effect of the electrolytic solution is inferior to that of Patent Document 1, and cannot be said to be sufficient.
JP-A-8-22815 JP-A-2005-276741

  The present invention further suppresses electrolyte reduction and improves maintenance-free properties, and when liquid reduction progresses and the electrolyte level decreases, replenishment work can be performed from the liquid stopper. A lead-acid battery that can be used for a longer period of time is provided.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is a lead storage battery in which a lid is provided with a liquid spout provided with a valve that opens according to a change in battery internal pressure. In order to discharge the gas in the battery to the outside of the battery, the liquid plug is provided with a discharge port, and the entire surface of each electrode plate surface of the positive electrode plate and the negative electrode plate is immersed in the electrolyte inside the battery. The positive electrode plate and the negative electrode plate respectively include a positive electrode lattice body and a negative electrode lattice body made of a Pb—Ca alloy, and at least one of the positive electrode plate and the negative electrode plate is a microporous film such as polyethylene. A sheet that is housed in the bag-shaped separator formed by the step of bonding a sheet that covers the discharge port to the cover surface, and a bonding portion in which the sheet and the cover are bonded to a bonding surface of the sheet and the cover And the sheet and the lid are joined together Provided that there is no non-joining portion is the non-joint portion indicates a lead-acid battery is provided as a gas discharge path for discharging to the atmosphere the exhaust gas at a position spaced from the discharge port from the discharge port.

  Moreover, the invention according to claim 2 of the present invention is the lead storage battery of claim 1, wherein the lead plate substantially free of Sb is used as a strap for collectively welding the electrode plates of the same polarity of the positive electrode plate and the negative electrode plate. 1 shows a lead storage battery using a lead alloy.

  The lead storage battery according to claim 3 of the present invention is the lead storage battery according to claim 1 or 2, wherein a Sn-containing layer including Sn is formed on at least a part of a surface of the positive electrode lattice body in contact with the active material. Is shown.

  According to a fourth aspect of the present invention, in the lead-acid battery according to the first, second, or third aspect, an Sb-containing layer containing Sb is formed on at least a part of a surface of the positive electrode lattice body that contacts the active material. This indicates a lead storage battery.

  And the invention which concerns on Claim 5 of this invention shows the lead storage battery which further contains Ag in the said Sb-containing layer of Claim 4.

  Furthermore, the invention according to claim 6 of the present invention is the lead storage battery according to claim 1, 2, 3, 4 or 5, wherein the valve opening pressure of the valve is 6 kPa or less.

  According to the configuration of the present invention described above, liquid reduction due to moisture evaporation of the lead storage battery can be remarkably suppressed. Further, even when the electrolyte level is lowered due to the long-term use of the lead storage battery, water can be further replenished. Therefore, the lead storage battery can be used for a longer period of time than a lead storage battery that cannot be refilled.

  Hereinafter, the structure of the lead acid battery by embodiment of this invention is demonstrated.

  The lead storage battery 1 according to the present invention has a positive electrode lattice and a negative electrode lattice made of a Pb—Ca alloy. A positive electrode plate 2 and a negative electrode plate 3 in which active materials corresponding to the respective polarities are filled in these lattice bodies are laminated via a separator 4 to constitute an electrode plate group 6. The positive electrode ear 2a and the negative electrode ear 3a for current collection provided on each of the positive electrode plate 2 and the negative electrode plate 3 are connected between the ear portions of the same polarity by the positive electrode strap 5a and the negative electrode strap 5b.

  The electrode plate group 6 is housed in a battery case 7, and the battery case 7 is closed with a lid 8. The battery case 7 is divided into cell chambers 7b by partition walls 7a so that a plurality of electrode plate groups 6 can be accommodated according to the battery voltage. For example, a lead storage battery for an automobile is usually a 12V battery, and the battery case 7 is partitioned into six cell chambers 7b by five partition walls 7a. Although not shown, an electrolytic solution containing dilute sulfuric acid as a main component in an amount soaking the entire surface of the positive electrode plate 2 and the negative electrode plate 3 is stored in the cell chamber 7b.

  The lid 8 is provided with a liquid injection port 9 for supplying an electrolytic solution or water to the cell chamber 7b for each cell chamber 7b, and a liquid port plug 10 is attached to the liquid injection port 9. Further, the liquid port plug 10 is provided with a discharge port 11 for discharging the gas inside the battery to the outside of the battery.

  In the lead storage battery 1 of the present invention, a sheet 12 covering the discharge port 11 provided in the liquid plug 10 is bonded to the lid 8 with an adhesive or the like. Note that the adhesive is not applied to the entire surface of the sheet 12 to which the lid 8 is bonded, but rather from the discharge port 11 to the end of the sheet 12 so as to guide the exhaust gas from the discharge port 11 to the outside of the battery. A portion where the adhesive is not applied over the portion 12a (corresponding to the non-joined portion in claim 1) is provided, and the other portion (the hatched portion A in FIG. 1, corresponding to the joined portion in claim 1) is provided with an adhesive. And the lid 8 and the sheet 12 are bonded together at the shaded area A. The gas from the discharge port 11 passes through the portion of the sheet 12 and the lid 8 that is not bonded to each other as the gas discharge path 13, and is discharged outside the battery at the end 12a of the sheet 12. In addition, the sheet | seat 12 can apply | coat the adhesive agent, such as an acrylic emulsion type | system | group, to acid-resistant sheets, such as polyethylene and a polypropylene.

  In the lead storage battery 1 of the present invention, as shown in FIG. 2, a valve 21 that opens according to the battery internal pressure is provided inside the liquid spout 10. Although various configurations can be applied as the configuration of the valve 21, the valve 21 illustrated in FIG. 2 illustrates an example in which the valve 21 is configured separately from the main body cylinder 22 inside the main body cylinder 22 of the liquid spigot 10. .

  In the example shown in FIG. 2, the valve 21 includes a valve housing body 23 including a bottom wall 23 b having an exhaust hole 23 a and a side wall 23 c provided around the bottom wall 23 b, and the valve housing body 23 includes a valve housing body 23. The valve body 23d is disposed so as to close the exhaust hole 23a. Further, the presser plate 23e is disposed on the valve body 23d so that the exhaust hole 23a is closed by the valve body 23d, and the presser plate 23e is fixed to the valve housing body 23. In addition, a gap may be provided between the pressing plate 23e and the valve body 23d, a sponge body 23f may be disposed in the gap, and the valve body 23d may be pressed against the bottom wall 23b.

  When the internal pressure of the cell chamber 7b rises due to gas generation from the electrode plate group 6, the valve body 23d and the sponge body 23f are compressed by the internal pressure, and a gap is generated between the bottom wall 23b and the valve body 23d. The gap expands as the internal pressure rises. When the internal pressure reaches a predetermined valve opening pressure, the gas in the cell chamber 7b is discharged to the discharge port 11 side provided in the liquid port plug 10 through this gap. When the internal pressure of the cell chamber 7b decreases due to this gas discharge, the exhaust hole 23a is closed again by the valve body 23d, and the valve is closed. In addition, when a vibration is applied to the lead storage battery, the electrolyte surface is shaken. If the electrolyte surface shakes vigorously and a large amount of electrolyte adheres to the valve 21, the electrolyte may ooze into the discharge port 11 when the valve is opened. It is preferable to suppress the adhesion of the electrolytic solution to the valve 21.

  In the lead storage battery 1 of the present invention, the valve is closed except when gas is generated from the electrode plate group by charging or the like. Therefore, the dissipation of the evaporated water from the electrolytic solution and the electrolytic solution mist to the outside of the battery, which is generated in the conventional open liquid type lead storage battery, is suppressed.

  When the lead storage battery 1 of the present invention is mounted on an automobile and is always charged when the vehicle is running, the valve opens, but the sheet 12 covering the discharge port becomes an exhaust resistance, so that a normal liquid lead storage battery is used. Compared to the above, gas is discharged slowly over a long period of time. During this time, the evaporated water and the electrolyte mist in the cell chamber 7b come into contact with the inner wall of the cell chamber 7b to condense and recirculate into the electrolyte solution, so that the moisture decrease due to gas discharge is suppressed.

  The increase in exhaust resistance after passing through the valve as described above contributes to the effect of suppressing liquid reduction according to the present invention. Therefore, it can be considered that liquid reduction can be suppressed by disposing a porous filter on the battery outside of the valve. However, even if a porous filter is used, a remarkable effect of suppressing liquid reduction cannot be obtained.

  The liquid reduction suppressing effect of the present invention is due to the increase in exhaust resistance outside the battery of the valve as described above, and the discharge port 11 provided in the liquid port plug 10 is covered with the sheet 12, and the exhaust gas is discharged to the discharge port. It is obtained by being discharged out of the battery at a position farther away and the shape of the gas exhaust passage 13.

  In particular, in lead-acid batteries for automobiles, outside air is constantly taken into the engine room and discharged out of the vehicle when the vehicle is running, so an air flow is generated around the battery. In conventional lead-acid batteries, the discharge port of the gas generated in the battery is exposed to the lid, so the air flow that flows outside the battery creates a negative pressure on the battery inside of the discharge port, facilitating gas discharge inside the battery. The At the same time, since water vapor and electrolyte mist inside the battery are also discharged out of the battery, the liquid reduction tends to proceed.

  Moreover, such a liquid reduction does not decrease so much even if the discharge port is covered with a porous filter. In the end, it is considered that the discharge of water vapor and electrolyte mist inside the battery is promoted because the air flow causes a negative pressure between the porous filter and the discharge port.

  In the present invention, a gas discharge passage 13 provided between the end 12 a serving as a final gas discharge port from the discharge port 11 in the liquid plug 10 is provided as a gap between the sheet 12 and the lid 8. Due to the air flow around the end 12a corresponding to the gas discharge path 13, the inside of the gas discharge path 13 is in a negative pressure state, so that the sheet 12 is pressed against the lid 8 by the atmospheric pressure, and the gas discharge path 13 is further narrowed, In some cases, some will close. As a result, the dissipation of the water vapor and the electrolyte mist in the cell chamber 7b through the gas discharge path 13 to the outside of the battery is remarkably suppressed.

  In the present invention, an example of a structure in which the valve 21 configured separately from the main body cylinder 22 is mounted on the main body cylinder 22 is shown, but the present invention is not limited to this structure, A valve may be provided integrally. Regardless of whether or not the valve 21 is provided integrally with the main body cylinder 22, the valve 21 may be made of a material having acid resistance and elasticity, for example, a material such as chloroprene rubber, silicon rubber, fluorine rubber, or EPDM rubber. it can. As described above, when the sponge body 23f is disposed between the valve body 23d and the pressing plate 23e, foamed rubber can be used as the sponge body 23f. In particular, an independent foam rubber is preferable because the elastic force hardly decreases with time.

  Further, the valve body 23d may be made of a non-elastic polyethylene sheet or a rubber sheet having high hardness, and a structure in which an elastic body such as foam rubber rich in elasticity is laminated thereon, and both of them are bonded to each other. It may be a thing.

  In addition, since the plasticizer in the valve body 23d may move to the bottom wall 23b and adhere to both, particularly when both are pressed against each other by the sponge body 23f or the like, silicone oil may be used as necessary. It is preferable to apply a liquid lubricant such as fluorinated oil to these contact surfaces. In the lead storage battery 1 of the present invention, since the oxygen gas absorption reaction at the negative electrode is suppressed in a state where all of the negative electrode plate surface is immersed in the electrolytic solution, the valve opening pressure is reduced to that of a normal control valve type lead storage battery. Thus, there is no significance to set it to 10 kPa or more. Moreover, since the battery case is deformed at such an internal pressure and the electrolyte surface changes, the valve opening pressure may be lower than this and 6.0 kPa or less.

  In order to obtain the liquid reduction suppression of the present invention more effectively, the positive electrode strap 5a and the negative electrode strap 5b are made of lead or a lead alloy substantially free of Sb. In general, lead-acid batteries for automobiles generally use an alloy containing about 2 to 4 wt% of Sb in the strap. This is because the alloy is far superior to an alloy not containing Sb in terms of ease of welding, mechanical strength, cost, and the like. In addition, the strap is a lump of alloy, has a smaller specific surface area than the active material, and it was thought that the influence of Sb in the strap on the liquid reduction characteristics of the battery was negligible. This is thought to be another reason why it was widely used as an alloy.

  However, it has been found that Sb contained in the strap elutes into the electrolytic solution while the battery is charged and discharged and reprecipitates on the negative electrode plate, thereby increasing the amount of liquid reduction. In particular, in the case of a long-life battery in which the durability of the positive electrode plate is significantly improved and the usable period of the battery is greatly extended, the increase in the amount of liquid reduction proceeds to a level that cannot be ignored.

  Therefore, it is preferable that the strap is made of lead or a lead alloy substantially free of Sb so as not to increase the liquid reduction amount during the lifetime. Needless to say, an amount of Sb that is of the order of impurities (about several ppm to several tens of ppm) and does not increase the liquid reduction amount is acceptable.

  As a specific alloy not containing Sb, for example, a Pb—Sn alloy containing 2 to 5 wt% Sn can be used.

  Further, as described above, in order to improve the durability of the positive electrode plate, particularly the durability of the positive electrode active material, the Sb-containing layer containing Sb on at least a part of the surface in contact with the active material of the positive electrode grid, for example, It is effective to provide a Pb—Sb alloy layer containing 2 to 10 wt% Sb. However, since Sb on the surface of the positive electrode lattice body may move to the negative electrode and increase the liquid reduction amount, it should be limited to an amount that does not cause an increase in the liquid reduction amount.

  Further, in order to improve the durability of the positive electrode plate in overdischarge, an Sn-containing layer, for example, a Pb—Sn alloy layer containing 2 to 10 wt% Sn is formed on the surface of the positive electrode lattice body in contact with the active material. Also good. Further, Sb having a concentration as described above may be added to the Sn-containing layer.

  Further, when a battery having an Sb layer formed on the surface of the positive electrode lattice is stored for a long period of time, the liquid reducing property is deteriorated. Therefore, in order to suppress such deterioration of the liquid reducing property after being left in the Sb layer, It is preferable to contain about 0.025 to 0.5 wt% of Ag. In addition, you may add Sn of the above density | concentration to this Sb containing layer containing Ag.

  Furthermore, one factor for accelerating the liquid reduction is a micro short-circuit phenomenon in the battery that occurs in the battery use process. This is thought to be mainly due to the fact that the cell voltage drops due to a short circuit caused by the active material dropped during use, the overvoltage applied to the cell during charging rises relatively, and water electrolysis is further promoted. It is done.

  Therefore, the separator is made into a bag shape, and at least one of the polar plates is accommodated to prevent a micro short circuit due to the falling active material. Preferably, as the separator material, polyethylene having very little active material penetration into the separator. The use of a microporous membrane made mainly of resin, inorganic powder, or mineral oil is extremely preferable in order to maintain the excellent liquid reducing properties according to the present invention until the end of its life.

  The effects of the present invention will be described below with reference to examples.

(Example 1)
The lead acid battery (80D26 type lead acid battery for start in JIS D5301) of the comparative example and the example of the present invention was manufactured, and the amount of liquid reduction when the battery was charged while applying vibration to the lead acid battery was evaluated.

  In both the batteries of the present invention and the comparative example, a positive electrode plate in which a Pb-0.07 wt% Ca-1.0 wt% Sn alloy expanded lattice body is filled with a positive electrode active material, Pb-0.07 wt% Ca-0.3 wt A negative electrode plate in which an expanded lattice body made of% Sn alloy was filled with a negative electrode active material was used.

  A bag obtained by processing a microporous membrane having a large number of micropores of 1 μm or less containing polyethylene resin and silica as main components and 10 wt% of mineral oil as an additive into a bag shape in which the left and right sides and the bottom are closed Any one of a sheet-like separator and a flat plate-like separator obtained by bonding a glass mat to synthetic pulp paper was used. In addition, when using a bag-shaped separator, the negative electrode plate was accommodated in the bag-shaped separator, and when using a flat plate-shaped separator, the glass mat was used so as to face the positive electrode plate surface.

  The battery A of the present invention example is the battery as shown in the above-described embodiment. The valve opening pressure of the valve 21 is 6 kPa. In the battery A, a bag-like separator that houses the positive electrode plate is used. Note that a Pb—Sb alloy containing 2.5 wt% Sb was used for both the positive strap and the negative strap.

  In addition, as the sheet | seat 12, the 0.2 mm-thick polypropylene sheet was used, and it affixed on the lid | cover with the acrylic emulsion adhesive.

  The battery B of the present invention is a battery in which the positive and negative strap alloys used in the battery A of the present invention were made of Pb-2.5 wt% Sn alloy containing 2.5 wt% Sn without containing Sb. . Other configurations are the same as those of the battery A.

  The battery C of the present invention example is a battery in which the negative electrode strap alloy used in the battery A of the present invention example is a Pb-2.5 wt% Sn alloy similar to the battery B. Other configurations are the same as those of the battery A.

  The battery D of the comparative example is a battery using a flat plate separator in which synthetic pulp paper and a glass mat are bonded together instead of the bag separator used in the battery A of the present invention. Other configurations are the same as the battery A.

  The battery E of the comparative example is a battery in which the valve 21 used in the battery A is detached from the main body cylinder 22 and a porous filter in which polypropylene resin particles are sintered is disposed at that position. Others are the same as the battery A.

  The battery F of the comparative example is a battery obtained by removing the sheet 12 bonded to the lid 8 from the battery E, and the other is the same as the battery E.

  The battery G of the comparative example is a battery obtained by removing the sheet 12 bonded to the lid 8 from the battery A of the present invention example, and the other is the same as the battery A.

  The battery H of the comparative example is a battery in which the positive electrode strap and the negative electrode strap of the battery F of the comparative example are both changed from Pb—Sb alloy to Pb—Sn alloy containing 2.5 wt% Sn. Absent.

  About each battery of above-mentioned battery AC of the example of this invention, and batteries D-H of a comparative example, constant voltage charge of 14.0V was performed for 2000 hours at environmental temperature 60 degreeC. During charging, the battery was vibrated in the vertical direction at an acceleration of 1 G and a frequency of 30 Hz. Moreover, it ventilated with the 50W blower along the battery cover upper surface.

  The above-described decrease in mass before and after charging of each battery was calculated as the liquid reduction amount, and the relative liquid reduction amount of each battery was calculated when the liquid reduction amount of the battery F of Comparative Example was set to 100. These results are shown in Table 1.

  From the results shown in Table 1, the liquid reduction amount of the batteries A to C of the present invention is 8 to 15% of the liquid reduction amount of the battery F of the comparative example, and the liquid reduction is remarkably suppressed. In particular, the battery B using a Pb—Sn alloy that does not contain Sb in both the positive and negative electrode straps has the smallest liquid reduction amount and is most preferable.

  About the battery E and the battery G of a comparative example, it is the liquid reduction amount of 62-65% similarly of the battery F of a comparative example, and the liquid reduction amount reduces to 62% in the sheet | seat 12 stuck together on the lid | cover 8, It can be seen that when the valve 21 is used alone in the liquid stopper, the liquid reduction amount is reduced to 65%.

  On the other hand, in the batteries of Invention Examples A to C provided with these configurations at the same time, as described above, the liquid reduction amount is 8 to 15% of the battery F of the comparative example. On the other hand, when the valve and the seat are each used alone, the amount of liquid reduction is 62% and 65%. From these results, the amount of liquid reduction expected when the valve and the seat are used simultaneously is 40. Although it is 3% (= 62% × 65%), in the example of the present invention, it can be seen that a synergistic effect is obtained, which is significantly lower than the assumed liquid reduction amount.

  For battery D using a flat separator as the separator, the amount of liquid reduction was 110, and even when the seat 12 and the valve 21 were used in combination, the liquid reduction progressed due to an internal short circuit. Therefore, it can be seen that a configuration in which at least one of the positive electrode plate and the negative electrode plate is accommodated by the bag-like separator is essential for suppressing liquid reduction.

(Example 2)
Like the battery B of the example of the present invention in Example 1, when the battery has no Sb at all, the charge acceptability of the battery is lowered. As a result, the service life may be drastically reduced when used in an insufficiently charged state.

  It is effective to form a lead-Sb alloy layer on the entire surface or a part of the surface in contact with the active material of the positive electrode grid body as a method for improving the life reduction due to such insufficient charging. The Sb concentration in the lead-Sb alloy layer is preferably between 2 and 10 wt%. If the Sb concentration is less than 2 wt%, the effect of improving the life is small, and if it exceeds 10 wt%, the liquid reduction increases.

  In the battery F and the battery H of the comparative example in Example 1, the battery B of the example of the present invention, and the battery B of the example of the present invention, a Pb—Sb alloy layer containing Sb having a concentration shown in Table 2 on the surface of the positive electrode lattice is 10 μm. Batteries B1 to B5 formed with a thickness were prepared. About these batteries, the light load life test prescribed | regulated by JISD5301 was done. In this example, the charging voltage was lowered from the standard 14.8V to 14.0V in order to further accelerate the insufficient charging state. Table 2 shows the results of the number of times of life in this life test. In addition, the lifetime number in Table 2 is shown by the relative value which set the lifetime number of the battery F of the comparative example to 100.

  In addition, from the results shown in Table 2, even in the battery B of the present invention example in which the positive electrode strap and the negative electrode strap do not contain Sb, the shortage of charging is suppressed by forming the Pb—Sb alloy layer on the surface of the positive electrode lattice. , The deterioration of the life characteristics is suppressed. In addition, about the batteries B1-B5 in Table 2, when the liquid reduction test similar to Example 1 was done, those liquid reduction amounts are 11-16 when the liquid reduction amount of the battery F of a comparative example is set to 100. It was found that the liquid reduction characteristics can be drastically improved while maintaining the life characteristics.

(Example 3)
As shown in Example 1, like the battery B of the example of the present invention in which the liquid reduction suppressing effect was most obtained, the positive electrode plate deteriorates due to overdischarge in the battery that does not contain Sb in the positive electrode and negative electrode straps, Charging may become impossible. Therefore, it is preferable to form a layer containing Sn, for example, a Pb—Sn alloy layer, on all or part of the surface in contact with the active material of the positive electrode lattice.

  In Example 3, a battery B in Example 1 and a Pb alloy layer having a Sn and / or Sb concentration shown in Table 3 on the surface in contact with the active material of the positive electrode grid body with a thickness of 10 μm were formed. Made a battery. Overdischarge resistance was evaluated by connecting a 10 W lamp between the terminals of each battery, charging at a constant voltage of 15.0 V (maximum current 25 A) after discharging for 6 months, and measuring the charging current after 30 minutes. . The results are shown in Table 3.

  From the results shown in Table 3, it can be seen that a charging current after overdischarge can be secured by forming a layer containing Sn on the surface of the positive electrode lattice body in contact with the active material.

Example 4
In Example 4, a battery B in Example 1 and a Pb alloy layer having a concentration of Sb and / or Ag shown in Table 4 on the surface in contact with the active material of the positive electrode grid body with a thickness of 10 μm were formed. Made a battery. About each battery, the same liquid reduction test as Example 1 was done. In this example, in order to confirm the effect of long-term storage of the battery on the liquid reduction amount, after confirming the liquid reduction amount of the battery in the initial state, each battery was left at 40 ° C. for 6 months and again. The same liquid reduction test as in Example 1 was performed. The results are shown in Table 4. In addition, the amount of liquid reduction is shown by the relative value which set the value of the battery F of the comparative example in Example 1 to 100.

  As shown in Table 4, in the battery B of the present invention example, when the Sb-containing layer was formed on the surface of the positive electrode grid (battery B3-1), the effect of improving the life characteristics shown in Example 2 was obtained, The amount of liquid reduction after storage tends to increase. This is considered because Sb in the Sb-containing layer moves to the negative electrode.

  However, it can be seen that by adding Ag to the Sb-containing layer, an increase in the amount of liquid reduction after storage is significantly suppressed. This is presumably because the addition of Ag improved the corrosion resistance of the Sb-containing layer and suppressed the transfer of Sb to the negative electrode. In addition, the effect by such Ag addition is acquired at 0.025 wt% or more. In this embodiment, the upper limit of the Ag concentration is 0.5 wt%. However, since Ag is a relatively expensive metal, the upper limit may be set in consideration of the battery manufacturing cost.

  In addition, although the example in which the Pb alloy layer containing Sb, Sn, and Ag formed on the surface of the positive electrode lattice is 10 μm thick is shown, the thickness may be larger than this. Further, in order to stably apply at least these Pb alloy layers to the positive electrode lattice surface layer by rolling the surface Pb alloy layer, the layer thickness of the Pb alloy is more preferably 2 μm or more.

  As described above, according to the configuration of the present invention, the liquid reduction amount of the lead storage battery can be extremely reduced. In addition, even when the electrolytic solution level is lowered due to long-term use of the lead storage battery, it is possible to easily refill water from the liquid port, and as a result, it is possible to provide a lead storage battery that can be used for a very long time at low cost. it can.

  The present invention is extremely suitable for various lead storage batteries including those for automobiles because the liquid reduction of the lead storage battery is extremely remarkably suppressed.

Sectional drawing which shows the lead acid battery of this invention The figure which shows the principal part cross section of the lead acid battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lead acid battery 2 Positive electrode plate 2a Positive electrode ear 3 Negative electrode plate 3a Negative electrode ear 4 Separator 5a Positive electrode strap 5b Negative electrode strap 6 Electrode plate group 7 Battery case 7a Bulkhead 7b Cell chamber 8 Lid 9 Injection port 10 Liquid port plug 11 Discharge port 12 Sheet 12a End portion 13 Gas discharge passage 21 Valve 22 Body cylinder 23 Valve housing body 23a Exhaust hole 23b Bottom wall 23c Side wall 23d Valve body 23e Holding plate 23f Sponge body 24 Splash-proof body

Claims (6)

A lead-acid battery with a lid fitted with a liquid port plug that opens according to changes in the battery internal pressure.When the valve is opened, the liquid port plug has a discharge port so that gas inside the battery is discharged to the outside of the battery. And the inside of the battery is housed in a state where the entire surface of each electrode plate of the positive electrode plate and the negative electrode plate is immersed in an electrolytic solution, and the positive electrode plate and the negative electrode plate are a positive electrode lattice body made of a Pb—Ca alloy, and Each of the positive electrode plate and the negative electrode plate is provided in a bag-like separator formed of a microporous film such as polyethylene, and a sheet covering the discharge port is covered with the lid. And a non-bonding portion where the sheet and the lid are not bonded to each other, and a non-bonding portion where the sheet and the lid are not bonded are provided on the bonding surface of the sheet and the lid. Part of the exhaust gas from the outlet Lead-acid battery is provided as a gas discharge path for discharging to the atmosphere at a location spaced from the discharge port. The lead acid battery according to claim 1, wherein lead or a lead alloy substantially free of Sb is used as a strap for collectively welding electrode plates of the same polarity of the positive electrode plate and the negative electrode plate. The lead acid battery according to claim 1 or 2, wherein an Sn-containing layer containing Sn is formed on at least a part of a surface of the positive electrode lattice body in contact with the active material. The lead acid battery according to claim 1, 2 or 3, wherein an Sb-containing layer containing Sb is formed on at least a part of a surface of the positive electrode lattice body in contact with the active material. The lead acid battery according to claim 4, further comprising Ag in the Sb-containing layer. The lead acid battery according to claim 1, 2, 3, 4 or 5, wherein a valve opening pressure of the valve is 6 kPa or less.

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