JP5748181B2 - Lead-acid battery and idling stop vehicle equipped with this lead-acid battery - Google Patents

Description

  The present invention relates to a lead-acid battery, and more particularly to prevention of a negative electrode from being burnt.

  It is known that when a lead-acid battery is used in an idling stop vehicle, the lead-acid battery is insufficiently charged, and thus the negative electrode is burnt. Here, the ear wrinkle is a phenomenon in which Pb at the ear or upper edge of the negative electrode is transformed into lead sulfate, leading to thinning, leading to cutting of the ear or upper edge. In the patent document 1 (WO2010 / 032782), the applicant made a negative electrode strap of a lead storage battery with a Pb-Sb alloy, provided a Pb-Sn alloy layer at the negative electrode ear, and 0.25 to 0.75 mass% as the negative electrode active material. It has been disclosed that carbon is contained. In this lead storage battery, it was possible to remarkably suppress the earburning in the idling stop life test at 25 ° C. stipulated in SBA S 0101: 2006. For example, the idling stop life can be extended by about 2.3 times compared to the case where the Pb—Sn alloy layer is not provided in the negative electrode ear.

  In order to prevent short circuit between the positive electrode plate and the negative electrode plate of the lead storage battery, the inventor provided a Pb-Sn surface layer on the negative electrode ear and the upper edge, and 0.03 to 0.3 mol / L Al ions in the electrolyte. (Patent Document 2 (WO2009 / 142220A). The Sn concentration in the Pb-Sn surface layer is 5 to 50 mass% and the balance is Pb and impurities. The Pb-Sn surface layer is provided, When the battery of Patent Document 2 in which Al ions are added to the electrolyte is used for an idling stop vehicle, it is 25 ° C compared to a lead-acid battery that does not have a Pb-Sn surface layer and does not add Al ions to the electrolyte. In the idling stop life test, the life was increased by about 2.6 times.

  However, in actual use of an idling stop vehicle, the temperature in the engine room may become 60 ° C. or higher during traveling depending on the region or season. And in the idling stop life test at a high temperature, it was found that the lead storage batteries of Patent Documents 1 and 2 are insufficient in the effect of suppressing the ear burn of the negative electrode and reach the life due to the ear burn. Therefore, the inventor searched for a lead-acid battery in which the negative electrode does not become harsh even when idling stop is repeated in a high temperature environment, and has reached the present invention.

  Here is related prior art. Patent Document 3 (JP2008-243487A) discloses that the addition of Li ions to the electrolyte of a lead storage battery increases the utilization rate of the positive electrode and improves the heavy load life, and the addition of Al ions improves the idling stop life. Yes. However, Patent Document 3 does not examine the thinning of the negative electrode or the influence of high temperature.

WO2010 / 032782A WO2009 / 142220A JP2008-243487A JPS52-136332A

  An object of the present invention is to suppress the burning of a negative electrode when a lead-acid battery is used in PSOC (Partial State of Charge), and in particular, to suppress the burning of a PSOC when used at a high temperature.

The present invention comprises a positive electrode plate, a negative electrode plate having an upper edge portion on an upper portion of a negative electrode lattice body provided with a negative electrode active material, and having an ear portion on an upper portion of the upper edge portion, and an electrolyte. In a lead storage battery in which at least one of the edge and the ear is provided with a surface layer of a Pb-Sn alloy, the electrolyte solution has a concentration of 0.02 mol / L or more and 0.2 mol / L or less of Li ions, and 0.02 mol Al ions having a concentration of not less than / L and not more than 0.2 mol / L.
Preferably, both the upper edge portion and the ear portion of the negative electrode plate are provided with a surface layer of a Pb—Sn alloy.

  Preferably, the Pb-Sn alloy contains 5 mass% or more and 40 mass% or less of Sn, and preferably the lead acid battery is for an idling stop vehicle. The Pb-Sn alloy may contain a third element such as Ag, As, Ba, Sb, and Se in addition to Pb and Sn.If the total content of these elements is 0.1 mass% or less, The effect of the present invention is not impaired. In addition to these elements, inevitable impurities such as Bi, Ni, Cu, Fe, etc. of 100 mass ppm or less may be included.

  The surface layer is provided on at least one of the negative electrode ear and the upper edge, and a Pb-Sn alloy foil is laminated and rolled on a required portion of the negative electrode grid alloy slab, and the negative electrode ear and upper edge are formed by an expanding method. Alternatively, a lattice in which a Pb—Sn surface layer is provided on the part may be used. Alternatively, Pb—Sn alloy hot-dip plating may be applied to the ears and upper edge of the lattice by a casting method.

In this specification, when the alloy composition is expressed as, for example, Pb-20 mass% Sn, it means an alloy containing 20 mass% of Sn, inevitable impurities (generally 100 mass ppm or less), and the balance being Pb. The concentration of Al ion and Li ion is expressed as the concentration (mol / L) of Al ion and Li ion per liter of electrolyte. One mole of Al ions corresponds to 171.05 g of aluminum sulfate (Al ₂ (SO ₄ ) ₃ ).

  When a Pb-Sn surface layer is provided on at least one of the negative electrode ear and the upper edge, and the electrolyte contains both Li ions and Al ions, high life performance is obtained in an idling stop life test at high temperatures ( 4 to 6). If any of the Pb—Sn-based surface layer of the negative electrode, the Li ion of the electrolytic solution, and the Al ion of the electrolytic solution is lacking, high life performance cannot be obtained.

  The present invention also resides in an idling stop vehicle equipped with the above lead storage battery. The idling stop vehicle uses a lead storage battery to start and ignite the engine, and uses the lead storage battery as a power source for lighting and the like. Then, the engine is stopped when the idling stop vehicle is stopped, and the engine is restarted when starting with the power of the lead-acid battery.

Front view schematically showing the negative grid After the high-temperature idling stop life test in an example using an electrolyte containing 0.2 mol / L of Li ions and 0.02 mol / L of Al ions and a negative electrode grid provided with a surface layer made of a Pb-40 mass% Sn alloy Electron micrograph showing the state of lead sulfate on the surface of the ear Ear part after high-temperature idling stop life test in a comparative example using an electrolyte containing 0.02 mol / L of Al ions with no Li ion and a negative electrode grid with a surface layer made of Pb-40 mass% Sn alloy Electron micrograph showing the state of lead sulfate on the surface Characteristic diagram showing life performance in high temperature idling stop life test when Li ion concentration is changed in electrolyte containing 0.2 mol / L of Al ion Characteristic diagram showing life performance in high temperature idling stop life test when Al ion concentration is changed in electrolyte containing 0.2 mol / L Li ion Characteristic diagram showing the life performance in the high temperature idling stop life test when the Sn concentration in the surface layer of the negative electrode ear and upper edge is changed

  Hereinafter, an optimum embodiment of the present invention will be described. In carrying out the present invention, the embodiments can be appropriately changed in accordance with common sense of those skilled in the art and disclosure of prior art.

Manufacture of lead-acid batteries
A positive electrode grid (thickness: 1 mm, height: 115 mm, width: 100 mm) was prepared from a Pb-Ca-Sn alloy sheet of Pb-0.05 mass% Ca-1.0 mass% Sn by the expanding method. The Sn content of Pb-0.05mass% Ca-0.5mass% Sn Pb-Ca-Sn alloy slab (10mm thickness) on both sides of the ear and upper edge is varied in the range of 5-50mass%. The Pb—Sn alloy foil (thickness 0.5 mm) was stacked, rolled and integrated. In the Pb—Sn alloy foil, the content of the third element such as Ag, As, Ba, Sb, and Se was 100 massppm or less. Next, a negative electrode grid was formed from the sheet provided with the surface layer by an expanding method. The structure of the negative electrode lattice is shown in FIG. 1, and the negative electrode lattice 1 includes an upper edge 2 on the upper portion of the lattice body 3, an ear 4 on the upper portion of the upper edge 2, and a lower edge 5 on the lower portion of the lattice body 3. It has. The Pb—Sn surface layer is provided on both the front and back surfaces of the upper edge portion 2 and the ear portion 4, and the size of the negative electrode lattice 1 is, for example, 1 mm thick, 115 mm high, and 100 mm wide. Further, in the negative electrode grid 1, 10 to 100 μm each of the front and back surfaces of the ear part and the upper edge part, and 45 μm each in the example is a Pb—Sn surface layer. The characteristics are almost constant in this thickness range.

  An active material paste was filled in the grid of the negative electrode and the positive electrode. The negative electrode active material paste is 11 mass% of 100 mass% lead powder of the ball mill method, 0.15 mass% lignin, 0.5 mass% barium sulfate, 0.2 mass% carbon, and 0.1 mass% binder resin added. And kneaded with 7 mass% of dilute sulfuric acid having a specific gravity of 1.40 at 20 ° C. The positive electrode active material paste is a paste made by adding 0.1mass% binder resin to 100mass% of ball milled lead powder and kneading with 13mass% water and 6mass% dilute sulfuric acid with a specific gravity of 1.40 at 20 ℃. It is. A grid filled with positive or negative active material paste is called an electrode plate. The positive electrode plate and the negative electrode plate were aged at 35 ° C. for 3 days, and the negative electrode plate was accommodated in a separator made of a microporous polyethylene bag. Seven positive electrode plates and eight negative electrode plates were alternately laminated, and the ears of the same polarity were welded together to form an electrode plate group, which was accommodated in a battery case. Then, a solution in which aluminum sulfate and lithium sulfate are dissolved in dilute sulfuric acid having a specific gravity of 1.23 at 20 ° C. is injected, and in a 25 ° C. water tank, an electric amount of 280% of the theoretical capacity of the positive electrode active material is applied for 18 hours. The tank was formed into a 55B24 lead acid battery. Al ions and Li ions may be added in any form, for example, lithium aluminate, aluminum hydroxide and lithium hydroxide, metal aluminum and lithium soluble salt in dilute sulfuric acid, or the like. The manufacturing method of lead powder is arbitrary, and the additive to an active material is also arbitrary.

Test and Results For each lead storage battery sample (sample No. 1-43),
・ Light load life test (JIS D 5301: 2006 9.5.5a)),
・ The battery industry association standard SBA S 0101: 2006 idling stop life test and high temperature idling stop life test (60 ° C) were performed. In addition, a high rate discharge test was conducted. The results are shown as an average value of three batteries each. In the idling stop life test of SBA S 0101, the test was conducted at 25 ° C, followed by a cycle of 59 seconds of discharge at 45A and 1 second of discharge at 300A followed by 60 seconds of charge at 14V (maximum current 100A). Leave for 40 to 48 hours per cycle, and let the number of cycles until the voltage at discharge is less than 7.2V be the life. In the high temperature idling stop life test, the idling stop life test was performed at 60 ° C.

  Tables 1 and 2 show the life performance, the ear thickness of the negative electrode during the life, and the liquid reduction rate in the high temperature idling stop life test. For the representative samples in Table 1, the number of cycles until the life in the light load life test is shown. Furthermore, the life performance in a high temperature idling stop life test with a representative sample is shown in FIGS. The state of lead sulfate on the surface of the negative electrode ear after the high temperature idling stop life test is shown in FIG. 2 for the battery 27 of the example and in FIG. 3 for the battery 30 of the comparative example. In Table 1, Table 2, and FIGS. 4 to 6, the life performance in the high temperature idling stop life test is expressed as a relative value with the battery 1 of the comparative example as 100%, and the ear thickness of the negative electrode is the thickness of each battery. The initial value is displayed as a relative value with 100%, and the liquid reduction rate is expressed as a relative value with the battery 1 of the comparative example as 100%. Further, the life performance in the light load life test and the idling stop life test of SBA S 0101 is shown as a relative value with the battery 1 of the comparative example as 100%.

  As shown in FIG. 4, if Li ions are absent, the life performance of the high temperature idling stop life test cannot be obtained. As shown in FIG. 5, even when Al ions are absent, the idling stop life performance at high temperature cannot be obtained. Furthermore, as shown in FIG. 6, idling stop life performance at high temperatures cannot be obtained unless a Pb—Sn-based surface layer is provided. That is, the long life of the high temperature idling stop life test can be obtained only when the three surface layers made of Li ions, Al ions, and Pb—Sn alloys are prepared. Further, as apparent from Table 1, the lifetime of the high-temperature idling stop lifetime test becomes longer as the qualitatively less earburning occurs.

  It has been known for a long time that Al ions in the electrolytic solution prevent the sulfation of the negative electrode (Patent Document 4: JPS52-136332), and it is considered that this also contributes to the prevention of the negative electrode from being burnt. In the system that does not contain Li ions, the inventor generated hydrogen in the Pb-Sn system surface layer of the negative electrode ear and upper edge during charging in the high temperature idling stop life test, competing with the reduction of lead sulfate. I found out. Hydrogen generation was particularly remarkable in the idling stop life test at high temperatures where the hydrogen overvoltage decreased, and was not found at 25 ° C. On the other hand, in the system containing Li ions, Al ions, and Pb—Sn surface layer, although hydrogen was generated during charging, the aggregation of lead sulfate particles was suppressed by Li ions. As shown, lead sulfate was porous and a large number of fine pores on the order of submicrons were observed. In FIG. 3, which contains Al ions but no Li ions, lead sulfate is dense, with a few relatively large pores and long grooves observed. In the structure shown in FIG. 2, the electrolyte easily diffuses inside the lead sulfate, and the reducing effect of lead sulfate is enhanced by the effect of Al ions. Therefore, even when hydrogen generation and lead sulfate reduction compete, lead sulfate is used. Is reversibly reduced to Pb. On the other hand, in the structure of FIG. 3, since lead sulfate is reduced only from the surface of the structure, even if the reducibility of lead sulfate is increased by the effect of Al ions, it can be estimated that the ear burn progresses.

  2 and 3 show the state of the ear after the life test. In FIG. 2 of the system containing Al ions and Li ions, lead sulfate is porous and a large number of fine pores on the order of submicrons are observed. . On the other hand, in FIG. 3, which contains Al ions but does not contain Li ions, lead sulfate is dense, and a few relatively large pores and long grooves are observed. In the structure of FIG. 2, the electrolytic solution diffuses inside the lead sulfate, and the lead sulfate is reversibly reduced to Pb. On the other hand, in the structure of FIG. 3, since lead sulfate is reduced only from the surface of the structure, it can be presumed that the produced lead sulfate is stable and the ear burnt occurs. As described above, the effect of Li ions is that the lead sulfate produced in the negative electrode ear or the like is made porous so as to be easily decomposed.

  The inventor examined Na ions, K ions, and Mg ions as candidates other than Li ions, but even when combined with 0.2 mol / L Al ions and a Pb-20 mass% Sn surface layer such as a negative electrode ear, the temperature is high. It was not effective as a life measure at idling stop (Table 2). As described above, in order to improve the performance in the idling stop life test at a high temperature, the surface layer made of a Pb—Sn alloy, Al ions, and Li ions are indispensable.

  Returning to Table 1 and FIGS. 2 to 4, the amount of addition of Li ions, Al ions, etc. will be examined. Both Li ion and Al ion have a sufficient effect at 0.02 mol / L, and even if added over 0.2 mol / L, the effect does not increase, and conversely a high rate discharge test (JIS D 5301: 2006, 9.5.3b )) Performance has begun to decline. Further, in the Pb—Sn surface layer, a sufficient effect has already been obtained with Sn 5 mass%, and since the liquid reduction rate increases when it exceeds 40 mass%, the Sn content is desirably 5 to 40 mass%.

  The electrolyte solution may contain 0.01 mol / L or less K ion, 0.015 mol / L or less Na ion, 0.01 mol / L or less Mg ion, etc. as impurities in addition to sulfate ion, Al ion, and Li ion. . In the example, the Pb-Sn alloy layer was provided on both the negative electrode ear and the upper edge. However, as in passenger cars, the negative electrode is not used under conditions of use where the stop time is almost limited to waiting for a signal or waiting for a pedestrian when turning right or left. The ears are easily corroded, and the upper edge is easily corroded under the use condition where the stop time is frequently repeated for loading and unloading of the load in addition to the stop time when waiting for a signal or turning left and right like a delivery vehicle. Therefore, a Pb—Sn alloy layer may be provided only on the negative electrode ear or only on the upper edge in accordance with the use conditions. In the example, the Pb—Sn alloy layers are provided on both the front and back surfaces of the negative electrode ear and the upper edge, but may be provided only on one side of these portions.

The embodiment has the following characteristics.
1) In a system including Li ions, Al ions, and a Pb-Sn surface layer, lead ions generated in the negative electrode ears or the like can be made porous by Li ions. As a result, the reduction of lead sulfate at the time of charging can be promoted, and ear burn can be prevented.
2) In a system containing Li ions, Al ions, and a Pb-Sn surface layer, Li ions can reduce lead sulfate even when hydrogen generation competes. Can be reduced to lead metal.
3) The combination of the surface layer made of Pb-Sn alloy and Al ions and Li ions in the electrolyte suppresses the negative electrode from being burnt at the high temperature idling stop and improves the battery life.
4) Lead-acid batteries suitable for the actual use conditions of idling stop vehicles, where the engine compartment becomes hot, can be obtained.

DESCRIPTION OF SYMBOLS 1 Negative electrode grid 2 Upper edge part 3 Grid main body 4 Ear | edge part 5 Lower edge part

Claims (4)

A negative electrode plate having a positive electrode plate, a negative electrode plate having an upper edge on the upper part of the negative electrode lattice body including the negative electrode active material and having an ear on the upper edge, and an electrolyte, and an upper edge and an ear of the negative electrode plate In a lead storage battery in which at least one of the parts has a surface layer of a Pb-Sn alloy,
The electrolytic solution contains Li ions having a concentration of 0.02 mol / L or more and 0.2 mol / L or less and Al ions having a concentration of 0.02 mol / L or more and 0.2 mol / L or less. Lead acid battery. The lead-acid battery according to claim 1 , wherein both the upper edge portion and the ear portion of the negative electrode plate are provided with a surface layer of a Pb-Sn alloy. The lead storage battery according to claim 1 or 2 , wherein the Pb-Sn alloy contains 5 mass% or more and 40 mass% or less of Sn. An idling stop vehicle comprising the lead storage battery according to claim 1 .