JP2003051334A - Sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed lead-acid battery with a long service life, allowing sufficient application in a deep charge/discharge cycle, especially even under a PSOC condition, by improving negative electrode deterioration caused by sulfation. SOLUTION: The manufacturing method for this sealed lead-acid battery uses both (a) a process for adding 1-5 pts.wt. carbon to a negative electrode active material of 100 pts.wt. and at least one of (b) a process for adding 0.01-0.1 pts.wt. bismuth to the negative electrode active material of 100 pts.wt. and (c) a process for adding at least one kind selected from K, Ca and Al of 5-50 g/l in terms of sodium sulphate to a sulfuric acid electrolytic solution impregnated into an electrode group.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed lead-acid battery used for automobiles, electric power storage, stationary backup, and the like. 2. Description of the Related Art A conventional sealed lead-acid battery is generally manufactured as follows. That is, a negative electrode active material and a positive electrode active material, for example, an active material mixture paste composed mainly of lead oxide and lead powder and kneaded with sulfuric acid, water or the like are filled in a lead alloy lattice substrate, respectively, and the unformed negative electrode A plate and an unformed positive electrode plate are prepared, and a required number of the plates are laminated via a retainer mat made of a porous material such as a glass fiber mat to assemble an electrode plate group, and this is housed in a battery case. A predetermined amount of sulfuric acid electrolytic solution is injected into the plate group to be impregnated and held. It was done. Since the electrolyte of such a sealed lead-acid battery is held in a retainer mat, it is easier to install and handle than a liquid lead-acid battery, and a sealed reaction in which oxygen gas generated at the positive electrode is reduced to water at the negative electrode. As a result, maintenance-free operation can be performed for a long period of time, and it is widely used as a backup power supply for information communication and electric power such as a battery for an automobile and a stationary battery. For details, see D. Bernold, “M.
aintenance-Free Batetries "(" maintenance-free batteries ") 1997:
Familiar with John Wiley & Sons. [0003] However, the capacity of the above-mentioned conventional sealed lead-acid battery rapidly decreases, especially when it is applied to an application in which deep charge and discharge are repeated. In particular, in order to realize economical power storage and peak-cut systems that make effective use of natural energy such as solar power and nighttime power, a long life that can recover the initial investment of the battery is an essential requirement. Further, the battery is required to have a hybrid function such as storing (charging) the regenerative braking power in the battery for the purpose of improving the fuel efficiency of the vehicle, and rapidly discharging the regenerative power for acceleration assist. Especially when regenerative operation is mainly used, the battery has a state of charge (SOC) of 5
The service life is short (below called PSOC) because it is operated around 0-70%. The reason for the short life is that the negative electrode is deteriorated by sulfation in which the generated discharge substance lead sulfate accumulates on the negative electrode surface. As a means of improving this, the addition of powdered or fibrous carbon to the negative electrode causes the carbon to enter the gaps between the lead sulfate crystals formed on the surface of the negative electrode and form a conductive path, resulting in a longer life.
of Power Sources 59 (1996) 153-157, (Journal of Power Sources 59 (1996) pp.153-157), JP-A-7-20133
It is disclosed in No. 1. However, the inventor has conducted various tests with a wide range of the added amount of carbon, but found that the effect of extending the life is limited and is insufficient for the above-mentioned various industrial applications. The inventor, in view of such knowledge,
A seal type that can improve the negative electrode deterioration due to charge / discharge cycles, prolong battery life, and exhibit sufficient capacity especially under deep charge / discharge cycles, for example, PSOC conditions, and is well suited for the various industrial applications described above. As a result of studying to obtain a lead-acid battery, a means to achieve its purpose was developed. SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and provides a long-life sealed lead-acid battery which achieves the above objects. The electrode group assembled by laminating an unformed negative electrode plate obtained by adding and kneading the active material mixture paste into a lead alloy porous substrate and a non-formed positive electrode plate via a retainer mat is used to form an electrode. After being housed in a tank, the electrode group is impregnated with a sulfuric acid electrolyte solution, and then subjected to a chemical conversion treatment, a sealed lead-acid battery,
(a) A sealed lead-acid battery characterized in that 1 to 5 parts by weight of carbon is added to 100 parts by weight of a negative electrode active material, and one or both of the following (b) and (c) are used in combination. (B) adding 0.01 to 0.1 part by weight of bismuth to 100 parts by weight of the negative electrode active material; and (c) adding at least one kind selected from K, Ca, and Al to the sulfuric acid electrolyte in an amount of 5 to 50 g / s in terms of sulfate. [0005] Carbon contributes to the formation of a conductive path between the above-mentioned lead sulfate crystals. However, carbon alone is not effective in providing a long-life battery. From the relation with the agent, the range of 1 to 5 parts by weight is effective as will be described later. The present invention, in addition to the addition of carbon,
By generating bismuth in 0.01 to 0.1 parts by weight per 100 parts by weight of the negative electrode active material or / and adding 5 to 50 g / l of at least one of K, Ca or Al to the electrolytic solution, it is generated at the time of discharge generated in the negative electrode. It is presumed that the crystal of lead sulfate is miniaturized or destabilized, and the deterioration of the negative electrode can be reduced. It is presumed that both of them affect the crystal growth of lead sulfate. If the amount is outside the above range, the intended long-life battery cannot be obtained. In other words, an excessively small amount of bismuth has an insufficient effect, while an excessively small amount of bismuth lowers the hydrogen overvoltage and promotes self-discharge. On the other hand, if the added component of K, Ca or Al to the electrolytic solution is too small, for example, less than 5 g / l, no effect is produced, and if it is excessive, for example, more than 50 g / l, the conductivity of the electrolytic solution is reduced. , The internal resistance increases. Thus, the present invention
The combined use of 1 to 5 parts by weight of carbon and the addition of bismuth and / or the addition of K, Ca or Al provides a synergistic effect to extend the battery life. DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealed lead-acid battery is generally manufactured as follows. That is, for example, lead oxide, which is an active material manufactured by a ball mill method, is kneaded with water or sulfuric acid to make the active material into a paste, which is then filled into a cast lattice substrate of, for example, lead or a lead alloy, and an unformed negative electrode plate. An unformed positive electrode plate is manufactured, and a required number of these positive and negative electrode plates are laminated via a retainer mat to assemble an electrode plate group. This is housed in a battery case, and after injecting a predetermined amount of sulfuric acid electrolyte, After forming a negative electrode plate with the lead oxide as metal spongy lead and a positive electrode plate with the lead oxide as lead peroxide by charging and charging, a battery case lid with a control valve is applied to form a sealed lead-acid battery. . As shown in Table 1, an embodiment of the sealed lead-acid battery of the present invention and a comparative example of a sealed lead-acid battery for comparison are shown in Table 1. The respective solutions were added to each other to produce the following. (1) Production of unformed negative electrode plate: 100 parts by weight of lead oxide (PbO) produced by a ball mill method as an anode active material, and acetylene black having a specific surface area of 70 m ² / g as a carbon powder are shown in Table 1. As shown, the amount added was 0.5 parts by weight to 7 parts.
Parts by weight, and further added bismuth oxide powder having an average particle size of about 1 μm, as shown in Table 1, by changing the addition amount from 0 to 0.12 parts by weight in terms of bismuth with respect to 100 parts by weight of the negative electrode active material. Then, lignin was added as an aqueous solution to the mixture, and then 10 parts by weight of ion-exchanged water and 100 parts by weight of lead oxide were kneaded while adding dilute sulfuric acid having a specific gravity of 1.36 to 100 parts of lead oxide. A mixture paste was prepared. The cup density of this paste was about 140 g / 2 in3. This is filled in a cast lattice substrate made of a lead-calcium alloy, and then aged in an atmosphere of 40 ° C. and 95% humidity for 24 hours, dried, and then dried to form an unformed negative electrode plate of each type shown in Table 1. Were produced in large numbers. (2) Production of unformed positive electrode plate: Lead oxide 1 as positive electrode active material
The mixture was kneaded while adding 10 parts by weight of ion-exchanged water and 10 parts by weight of dilute sulfuric acid having a specific gravity of 1.27 to 00 parts by weight to produce a positive electrode paste. The cup density of this paste was about 140 g / 2 in3. This paste was filled into a cast lattice substrate made of a calcium alloy, then aged for 24 hours in an atmosphere of 40 ° C. and 95% humidity, and then dried to produce a large number of one type of unformed electrode plate for a positive electrode. (3) Assembly of sealed lead-acid battery and preparation and formation of various sulfuric acid electrolytes: between these various unformed anode plates and the above-mentioned unformed cathode plates, about 10% An electrode group is assembled by laminating a retainer mat separator with a thickness of 0.8 mm when pressed at 20 kPa, which is made by adding silica powder, and assembling the electrode group. After welding, this was put into a battery case made of PP, and covered by heat sealing. Next, into each of the battery cases manufactured in this manner, those prepared by preparing various sulfuric acid electrolytic solutions used for battery case formation as follows were injected. That is, the specific gravity of the sulfuric acid electrolyte was set to 1.20, and one or more of each cation of K (lithium), Ca (calcium), and Al (aluminum) was shown in Table 1 as a sulfate in each electrolyte. The various electrolyte solutions prepared by adding and dissolving at different amounts were added in an amount of 100% of the theoretical space volume of the electrode group, and were impregnated into the electrode groups in the respective battery containers. . As shown in Table 1, for comparison, the above-mentioned cation was not added to the electrolytic solution, and sodium, which was conventionally known as an additive for preventing short-circuiting in a discharged state, was added to the electrolytic solution as a sulfate. We prepared what we did and what we didn't. Next, all these various batteries were overcharged by 200% of the theoretical capacity in a water bath at 40 ° C. to form a battery case, thereby producing 2 V sealed lead storage batteries. In a capacity test of the batteries performed after the formation of each of these batteries, the 5-hour rate capacity was 20 Ah. Each of the thus manufactured sealed lead-acid batteries was fully charged at 25 ° C. at a 5-hour rate current, and the SOC was adjusted to 60% at a 5-hour rate current. That is, discharge for 8 Ah was performed. Next, the ambient temperature was adjusted so that the battery temperature became 40 ° C., and a constant current discharge of 60 A, 60 seconds, 200 A, 1 second and 60 A were performed.
A, 65 seconds, 80 A, 5 seconds, upper limit voltage 2.40V constant current
An endurance acceleration test was performed in which the combination of constant voltage charging was one cycle. In addition, evenly charge every 1600 cycles,
The battery was fully charged to eliminate significant electrode sulfation, and the subsequent discharge adjusted the battery's SOC to 60%. Then, the charge / discharge test was repeated until the voltage at the time of discharging at 200 A became lower than 1.6 V / cell, and the time when the voltage became lower than 6 V / cell was regarded as the life of the battery. Desirable life is at least 20,000 cycles. The test results are shown in Table 1 below. [Table 1] As is apparent from Table 1, the negative electrode active material 100
The amount of carbon to be added is in the range of 1 to 5 parts by weight, and bismuth is added to 100 parts by weight of the negative electrode active material.
0.01 to 0.1 parts by weight of K, Ca
Or at least one of Al in terms of sulfate, 5 to 50 g /
By combining one or both of the additions of l, a synergistic effect of obtaining a sealed lead-acid battery having a remarkably longer life than before can be obtained even under the above-mentioned deep charge / discharge cycle, particularly under the PSOC condition. In particular, it can be seen that when the amount of carbon added is 2 to 3 parts by weight, a more excellent life extension effect can be obtained. In addition, according to the present invention, especially when the addition amount of bismuth is 0.03 to 0.07 parts by weight, and when the addition amount of K, Ca and Al sulfates is 10 to 40 g / l, it is found that the cycle life is particularly improved. . As the carbon, graphite, amorphous powder or fibrous powder can be mixed with lead oxide powder of the negative electrode active material instead of the above-mentioned acetylene black powder. As bismuth, other oxides of bismuth oxide, desired bismuth compounds such as sulfates or metal powders can be added to the active material in the form of a metal powder. You may make it add in an alloy state. Bismuth is preferably added only to the negative electrode active material, and when added to the positive electrode active material, it lowers oxygen overvoltage, promotes generation of oxygen gas, and the generated oxygen gas undergoes a recombination reaction with the negative electrode. As a result, the potential of the negative electrode tends to shift to the noble side, and as a result, the reduction of lead sulfate is suppressed. Therefore, it is desirable to avoid adding the negative electrode to the positive electrode in order to prevent sulfation.
In the production of the negative electrode, well-known lignin and barium sulfate, which are known as an expanding agent and an anti-shrinking agent, may be added. As described above, according to the first aspect of the present invention, compared with a conventional sealed lead-acid battery using a negative electrode to which only carbon is added, a deeper charge / discharge cycle, particularly, a PSOC condition can be achieved. It is possible to provide a sealed lead-acid battery with significantly extended cycle life, for electric vehicles, for power storage,
The present invention provides a sealed lead-acid battery suitable for various industrial uses which is sufficient for stationary backup.

Continuation of front page    (72) Inventor Kozo Sogabe             23-6 Tsukushi, Funabashi-cho, Joban-shi, Iwaki-shi               Furukawa Battery Co., Ltd. Iwaki Office F term (reference) 5H028 AA05 AA06 EE01 FF04 HH01                       HH02                 5H050 AA07 BA10 CA06 CB15 EA02                       HA01

Claims (1)

Claims 1. An unformed negative electrode plate obtained by filling a lead alloy porous substrate with a paste of an active material mixture obtained by adding and kneading carbon to a negative electrode active material via a retainer mat. An electrode group assembled by laminating with an unformed positive electrode plate is housed in a battery case, and the electrode group is impregnated with a sulfuric acid electrolytic solution, and then subjected to a chemical conversion treatment. Negative electrode active material 100
Adding 1 to 5 parts by weight of carbon to parts by weight and the following (b)
(c) A sealed lead-acid battery using either or both of them. (B) adding 0.01 to 0.1 part by weight of bismuth to 100 parts by weight of the negative electrode active material; and (c) adding at least one kind selected from K, Ca, and Al to the sulfuric acid electrolyte in an amount of 5 to 50 g / s in terms of sulfate. l addition