JP2016189298A - Lead acid battery - Google Patents

Abstract

[Configuration] The lead-acid battery contains an organic shrunk agent with an S element content of 3900 μmol / g or more and 6000 μmol / g or less, and the ratio of the volume of the electrolyte to the total volume of the positive and negative electrode plates is 1.1 or more 3.0 or less. [Effect] Excellent low-temperature high-rate discharge performance, and low-rate discharge performance is in a practical range. [Selection] Figure 2

Description

  The present invention relates to a lead storage battery.

Organic anti-shrinking agents such as lignin sulfonic acid and bisphenol condensates are added to the negative electrode material of the lead storage battery. The organic shrunk agent prevents the shrinkage of the negative electrode material, temporarily captures Pb ²⁺ ions during charge and discharge, and further improves the low temperature high rate discharge performance.

  Regarding the S element content of the organic shrinking agent, Patent Document 1 (Patent 3385879) states that the variation in low-temperature high-rate discharge performance can be reduced when the ligninsulfonic acid sulfonation rate is 90% or more. Patent Document 2 (Japanese Patent Laid-Open No. 2013-41848) states that charge acceptance performance is improved when a bisphenol condensate having an S element content of 6 to 10 mass% is used instead of lignin sulfonic acid.

Patent 3385879 JP2013-41848

  The inventor examined the performance of the lead-acid battery when the S element content per mass of the organic shrinking agent was increased. As a result, it was found that the higher the S element content, the smaller the colloidal particle diameter of the organic shrinking agent, and the smaller the pore diameter of the negative electrode material. Furthermore, it has been found that when the S element content is high, the specific resistance of the negative electrode material is reduced and the low-temperature high-rate discharge performance is improved. The inventor examined the effect of the ratio of the volume of the electrolyte and the total volume of the positive and negative electrodes in addition to the S element content per mass of the organic shrinkage agent on the low-temperature high-rate discharge performance.

  The subject of this invention is providing the lead acid battery which is excellent in low-temperature high-rate discharge performance, and has low-rate discharge performance in a practical range.

  The lead storage battery of the present invention has an organic shrunk agent having an S element content of 3900 μmol / g or more and 6000 μmol / g or less, and the ratio of the volume of the electrolyte and the total volume of the positive and negative electrode plates is 3.0 or less. It is. The S element content of the organic shrinking agent is preferably 4300 μmol / g or more and 6000 μmol / g or less, and most preferably 4500 μmol / g or more and 6000 μmol / g or less.

  FIG. 2 shows how the S element content in the organic shrinking agent and the ratio of the volume of the electrolyte and the total volume of the positive and negative electrodes affect the duration of the low temperature high rate discharge. The higher the S element content and the smaller the volume ratio, the longer the duration of the low temperature high rate discharge. The duration increases greatly when the volume ratio is between 3.5 and 3.0, and gradually increases between 3.0 and 1.8. Therefore, in order to improve the low-temperature high-rate discharge performance, it is important that the ratio of the volume of the electrolyte and the total volume of the positive and negative electrode plates is 3.0 or less.

  Moreover, as shown in FIG. 3 and Table 3, the low rate discharge capacity (0.2 CA discharge duration) is increased by increasing the volume ratio. In order to reduce the volume ratio, for example, the distance between the electrode plates is reduced, and the electrolyte solution is retained in the AGM separator to eliminate the free electrolyte solution. The amount of electrolyte can be reduced. In order to increase the volume ratio, for example, the distance between the electrode plates is increased, the opening volume of the electrode plates is increased, the liquid surface height of the electrolyte is increased, or a battery case that is larger than the electrode plate is used. Free electrolyte can be increased. However, it is not realistic to increase the level of the liquid surface meaninglessly or to use an unnaturally large battery case. Therefore, it can be said that by reducing the volume ratio within the practically possible design range, the low-temperature high-rate discharge performance is increased, and by increasing the volume ratio, the low-rate discharge performance is improved.

  Since the low-temperature high-rate discharge performance is improved together with the S element content in the organic shrunk agent, the S element content in the organic shrunk agent is 3900 μmol / g or more, preferably 4000 μmol / g or more, more preferably 4300 μmol / g or more. Most preferably, the amount is 4500 μmol / g or more. However, when the S element content exceeds 6000 μmol / g, the low-rate discharge performance deteriorates (FIG. 3). Therefore, in order to make the low rate discharge performance within a practical range, the S element content in the organic anti-shrink agent is set to 6000 μmol / g or less.

  As described above, when the volume ratio between the volume of the electrolyte and the total volume of the positive and negative electrode plates is 3.0 or less and the S element content of the organic shrinking agent is 3900 μmol / g or more and 6000 μmol / g or less, low-temperature high-rate discharge A lead-acid battery having excellent performance and low rate discharge performance within a practical range can be obtained. The type of storage battery may be a liquid type or a control valve type.

  However, when the content of S element in the organic shrinking agent is 4500 μmol / g or more and the above volume ratio is 1.0, a short circuit is likely to occur when the electrolyte is injected. For this reason, the volume ratio is preferably 1.1 or more and 3.0 or less.

  Preferably, the S element in the organic shrinking agent is contained as a sulfonic acid group or a sulfonyl group. These groups are strongly polar hydrophilic groups, and are likely to appear on the surface of the organic anti-shrink agent particles in the electrolyte due to electrostatic repulsion between these groups. For this reason, the association of colloidal organic shrinking agent particles is limited, and the size of the organic shrinking agent particles, in other words, the colloidal particle diameter of the organic shrinking agent is reduced. In addition, even if it contains S element as a sulfonic acid group, and it contains as a sulfonyl group, the performance of a lead storage battery is substantially the same (Table 2). Also, it is a synthetic polymer organic shrinking agent, and the performance of lead-acid batteries is almost the same as long as the skeleton is a bisphenol condensate or naphthalene condensate with the same S element content (Table 2). .

When introducing a sulfonic acid group into the phenyl group of lignin, it is difficult to introduce one or more sulfonic acid groups per phenyl group, so it is also difficult to make the S element content 3900 μmol / g or more. However, when the sulfonic acid group and the sulfonyl group are not directly introduced into the phenyl group, but an alkyl group is placed in the middle and introduced into the phenyl group or the propyl group of lignin, the S element content of lignin can be increased to 3900 μmol / g or more. Accordingly, an organic shrinkage agent in which a sulfonic acid group or a sulfonyl group is introduced into lignin may be used.

  Preferably, the organic shrinking agent is a synthetic polymer, most preferably a condensate of bisphenols. Unlike lignin, when a sulfonic acid group or a sulfonyl group is introduced into a condensate of bisphenols or a condensate of naphthalene, the S element content can be easily increased to 3900 μmol / g or more. Accordingly, the organic shrinking agent is preferably a synthetic polymer. Since the bisphenol S condensate contains a sulfonyl group, the S element content can be increased. A formaldehyde condensate of β-naphthalene sulfonic acid is available under the trade name “Demol” of Kao Corporation, and can be used by adjusting the concentration of the sulfonic acid group. Of the synthetic polymers, bisphenol condensates that have been used in lead-acid batteries are preferred.

This invention has the following features.
1) The low temperature high-rate discharge performance is improved by setting the S element content of the organic shrinking agent to 3900 μmol / g or more and 6000 μmol / g or less.
2) The low-rate discharge performance reaches a peak when the S element content of the organic anti-shrinking agent is around 5000 μmol / g, and decreases significantly when it exceeds 6000 μmol / g.
3) Improve the low-temperature high-rate discharge performance by setting the volume ratio of the electrolyte to the electrode plate to 3.0 or less.
4) When the content of S element in the organic shrinking agent is 4500 μmol / g or more, there is a problem that a short circuit occurs after 2 hours of injection. This problem occurs when the S element content in the organic shrinkage agent exceeds 4000 μmol / g and the above volume ratio is 1.0 or less. Therefore, a short circuit is prevented by making the volume ratio larger than 1.0, and a short circuit is surely prevented by setting the volume ratio to 1.1 or more.
5) Low-temperature high-rate discharge performance increases when the volume ratio of the electrolyte to the electrode plate approaches 1.1, and low-rate discharge performance improves when the above volume approaches 3.0. When the volume ratio is less than 1.1, the low-rate discharge performance is remarkably lowered, but the low-temperature high-rate discharge performance is slightly improved. On the other hand, when the volume ratio exceeds 3.0, the low-temperature high-rate discharge performance is remarkably deteriorated, but the improvement of the low-rate discharge performance is slight.
6) The low temperature high-rate discharge performance is remarkably improved by setting the S element content in the organic shrinking agent to 4300 μmol / g or more and 6000 μmol / g or less.
7) By using a synthetic polymer as the organic shrinking agent, the S element content can be easily increased.
8) Organic shrunk agents composed of condensates of bisphenols have been used for many years in lead-acid batteries.
9) By containing the S element as a sulfonic acid group or a sulfonyl group, the colloidal particle diameter of the organic anti-shrink agent can be reduced, thereby reducing the average pore diameter of the negative electrode material.

Cross-sectional view of main parts of lead-acid battery Characteristic diagram showing the relationship between S element content in organic pre-shrink agent and low temperature high rate discharge duration Characteristic diagram showing the relationship between S element content in organic shrinkage and 0.2CA discharge duration Characteristic diagram showing the relationship between the ratio of electrolyte volume to electrode plate volume and reaction resistance of lead-acid battery

  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. The electrode plate is composed of a current collector such as a grid and an electrode material supported by the current collector. The electrode material is an electromotive force such as a bisphenol condensate, carbon black, barium sulfate, or a synthetic fiber reinforcement. Contains materials that do not participate in the reaction. The negative electrode material is a material mainly composed of spongy lead, and the positive electrode material is a material mainly composed of lead dioxide. In the embodiment, the electrode material is called an active material for simplicity. In addition, the organic shrunk agent may be simply referred to as a shrunk agent, and the S element content in the organic shrunk agent may be referred to as “S element content”. Furthermore, the volume ratio between the volume of the electrolytic solution and the total volume of the positive and negative electrode plates may be referred to as a “volume ratio”.

  FIG. 1 shows a main part of a lead-acid battery, 2 is an electrode plate, and positive and negative electrode plates are alternately arranged, and a negative electrode plate is accommodated in a microporous polyethylene separator (not shown). 4 is an electrolytic solution, which may be held in an AGM separator (a mat-like separator made of glass fibers) or the like, or may be gelled. 6 is a battery case, 8 is an ear of the electrode plate 2, 10 is a strap for connecting the electrode plates to each other, and 12 is a pole column. In the present invention, the total volume of the positive and negative electrode plates 2 is used as the electrode plate volume. If there are ears 8 and legs not shown, these are included in the volume, but the strap 10 is not included. The volume of the electrolytic solution is the total volume of the electrolytic solution in the battery case, including not only those existing between the electrode plates 2 but also those impregnated in the electrode plates 2.

  A method for measuring the volume of the electrolytic solution will be described in the case of a liquid lead-acid battery. Perform the measurement at 25 ° C. If the electrolyte is depleted, fill up to the maximum liquid level. All the electrolyte solution that can be taken out from the storage battery is taken out, and the volume and specific gravity are obtained. Next, members such as an electrode plate and a separator are taken out and their masses are measured. The member taken out is washed with water and dried, and the mass excluding the electrolytic solution is measured again. The difference in mass before and after washing and drying is divided by the specific gravity of the electrolytic solution to obtain the volume of the electrolytic solution contained in the member. As described above, the volume of the electrolytic solution contained in the member is added to the volume of the free electrolytic solution outside the electrode plate to obtain the total volume of the electrolytic solution.

  A method for measuring the volume of the electrolyte will be described for a control valve type lead-acid battery using an AGM separator or the like. First, in order to avoid the influence of liquid reduction, lead-acid batteries that are as unused as possible are used. Since the specific gravity may vary depending on the height position in the separator, the electrolyte is collected from above and below the separator, and the specific gravity is averaged at the top and bottom. Also, since it is difficult to sufficiently remove the electrolyte from the AGM separator, etc., these are washed and dried in the same manner as members such as the electrode plate, and the mass of the electrolyte is determined from the difference in mass before and after the average specific gravity. Divided by the volume of the electrolyte contained in the AGM separator or the like. Furthermore, if there is free electrolyte, it is collected and the volume is measured. The volume of the electrolyte contained in the electrode plate is measured in the same manner as in the liquid type. Therefore, the difference in mass between before and after washing the electrode plate with water and drying is divided by the average specific gravity of the electrolyte solution to obtain the volume of the electrolyte solution. If the electrolyte is gelled or held in granular silica instead of using an AGM separator, the difference between the mass of these components before washing and drying and the mass after washing and drying is determined. Then, the difference is divided by the above average specific gravity to obtain the volume of the electrolytic solution. And the sum total of the volume of the electrolyte solution of each part is calculated | required.

A lead storage battery was manufactured using a negative electrode material containing an organic shrinkage agent (S element content 5000 μmol / g) composed of preliminary test lead powder, synthetic fiber reinforcement, barium sulfate, and a bisphenol condensate. A negative electrode active material was collected from a pre-formed negative electrode plate, a volume-based pore size distribution was measured by a mercury intrusion method, and a pore having a pore size of 100 μm or more was removed to obtain a central pore size of the negative electrode material. Further, the colloidal particle diameter of the organic shrinkage agent in sulfuric acid at a concentration equivalent to the electrolyte was measured by a laser light scattering method, and the median value of the colloidal particle diameter on a volume basis was determined.

  First, the effect of the concentration of the organic pre-shrinking agent was examined. The organic shrunk agent has an S element content of 5000 μmol / g, of which the S element derived from the sulfonyl group is 1400 μmol / g, the rest is derived from the sulfonic acid group, and the organic shrunk agent concentration is 0.10 mass%, 0.15 mass%, 0.20 mass It was changed in 3 steps. The results are shown in Table 1. Increasing the concentration of the organic shrinkage agent improved the low-temperature high-rate discharge performance, but did not change the low-rate discharge performance (0.2 CA discharge duration). From this, the range of the preferable organic shrinkage agent concentration was set to 0.05 mass% or more and 0.3 mass% or less.

  Next, it was confirmed that the S element in the organic shrinking agent may exist as a sulfonic acid group or as a sulfonyl group. The S element content in the organic shrunk agent is fixed to 5000 μmol / g, the concentration of the organic shrunk agent is fixed to 0.15 mass%, and the ratio of the S element content derived from the sulfonyl group and the S element content derived from the sulfonic acid group is Changed. As shown in Table 2, the influence of the sulfonyl group or the sulfonic acid group was small. Similar results were obtained even when the mixing ratio of bisphenol A, S, and F was changed and the mixture was subjected to condensation and sulfonation to change the S element content. Furthermore, even if a naphthalene sulfonic acid condensate was used instead of the bisphenol condensate, the effect was the same as long as the S element content was the same.

Production of lead-acid battery Lead powder, organic shrinkage agent composed of bisphenol condensate, barium sulfate, carbon black, and synthetic fiber reinforcing material were kneaded with water and sulfuric acid to obtain a negative electrode active material paste. Contains 0.10 mass% organic shrinkage agent, 1.0 mass% barium sulfate, 0.05 mass% synthetic fiber reinforcement, and 0.2 mass% carbon black in addition to the active anode active material (strictly, negative electrode material) after conversion. I let you. The preferred content range of these components is 0.05 mass% or more and 0.3 mass% or less for organic shrinkage agent, 0.5 mass% or more and 2.0 mass% or less for barium sulfate, and 0.03 mass% or more and 0.2 mass% or less for synthetic fiber reinforcement. Carbon such as carbon black is 3.0 mass% or less. The negative electrode active material may contain components other than those described above. The negative electrode active material paste was filled in an expanded lattice made of a Pb—Ca—Sn alloy, dried and aged to obtain an unformed negative electrode plate.

  In the examples, a condensate of bisphenol A introduced with a sulfonic acid group by formaldehyde and a condensate of bisphenol S introduced with a sulfonic acid group by formaldehyde were used as the organic shrinking agents. Then, the conditions for sulfonation were made stronger than before, and the average value of the number of sulfonic acid groups per molecule of bisphenol was increased. The mixture of bisphenol A, F and S was condensed and then sulfonated. In this way, the S element content was adjusted in the range of 3000 μmol / g to 7500 μmol / g. Separately from this, lignin sulfonic acid having an S element content of 600 μmol / g was used as a comparative example. The kind of lead powder, manufacturing conditions, etc. are arbitrary, and the negative electrode active material may contain components other than those described above.

  Lead powder and a synthetic fiber reinforcing material (0.1 mass% with respect to the formed positive electrode active material) were kneaded with water and sulfuric acid to obtain a positive electrode active material paste. This paste was filled in a Pb—Ca—Sn-based expanded lattice, dried and aged to obtain an unformed positive electrode plate. Wrapping the unformed negative electrode plate with a microporous polyethylene separator, setting it in the battery case together with the positive electrode plate, and calculating the water decomposition amount during the formation so that the specific gravity of the electrolyte after the formation becomes a predetermined concentration An electrolytic solution made of sulfuric acid was added to form a battery case, and a lead-acid battery with 12 V output and a 5-hour rate current (0.2 CA) of 5.0 A was obtained. The volume of the electrolyte solution poured into the battery is converted to the volume at 25 ° C., and is defined as the volume of the electrolyte solution in the claims. The specific gravity of the electrolytic solution (substantially the specific gravity of sulfuric acid) is preferably 1.26 to 1.32 at 25 ° C. The electrolytic solution may contain known additives such as aluminum ions, sodium ions, and lithium ions.

The ratio between the volume of the electrolyte and the total volume of the electrode plate is
・ Change mainly by changing the distance between positive and negative plates,
・ In areas where there is little electrolyte, hold the electrolyte in the AGM separator to eliminate the free electrolyte.
It changed by.

Method for Measuring S Element Content The S element content (hereinafter simply referred to as “S element content”) of the organic shrinkage agent in the negative electrode active material is measured as follows. The fully charged lead acid battery is disassembled, the negative electrode plate is taken out, the sulfuric acid content is removed by washing with water, and the dry weight is measured. The active material is separated from the negative electrode plate and, for example, immersed in a 1 mol / L NaOH aqueous solution to extract the organic shrunk agent, and the type of the organic shrunk agent is qualitatively determined from an ultraviolet-visible absorption spectrum or the like. If the qualitative characteristics are incomplete with only the absorption spectrum, GC-MS, NMR, etc. may be used in combination. In addition, the content of the organic shrinking agent is measured using the absorbance at the absorption wavelength and the calibration curve for each type of organic shrinking agent. Further, for example, a NaOH aqueous solution of an organic shrinkage agent obtained by extraction from an active material is desalted, concentrated and dried. The S element content in the organic shrinkage agent is obtained by converting S element in 0.1 g of the organic shrinkage agent into sulfuric acid by the oxygen combustion flask method, and titrating the eluate with barium perchlorate using thrin as an indicator. In the organic shrinkage-preventing agent, particularly the synthetic polymer shrinkage-preventing agent, the S element may be contained as a sulfonyl group or a sulfonic acid group.

Performance Test The following initial performance was measured for a battery in which the S element content of the organic shrinkage-preventing agent was changed.
・ 0.2CA discharge duration: Time until the terminal voltage drops to 10.5V when discharging at a current value of 0.2CA ・ Low temperature high-rate discharge duration: When discharging at 150A in a -15 ℃ air tank Time until terminal voltage drops to 6.0V / Reaction resistance: Reaction resistance component calculated from Cole-Cole plot obtained by AC impedance measurement

  In addition to these, as a high-temperature overcharge test, a test was conducted in which charging was performed at a current of 2.5 A at 65 ° C. for 240 hours, and then the low-temperature high-rate discharge duration was measured. The test results are shown in Tables 3 to 6, and the main results are extracted and shown again in FIGS. When the volume ratio was 1.0 and the S element content was 4500 μmol / g or more, shorts occurred frequently when the test was conducted 2 hours after the injection of the electrolyte.

  The low temperature high-rate discharge duration is shown in FIG. 2 with the S element content on the horizontal axis. The higher the S element content, the longer the low temperature high rate discharge duration, and the smaller the volume ratio, the longer. . And the low-temperature high-rate discharge duration increased rapidly when the volume ratio was between 3.5 and 3.0. From the above, it can be seen that when the volume ratio exceeds 3.0, the low-temperature high-rate discharge performance is impaired, which is considered to be caused by the tendency that the reaction resistance increases between the volume ratio of 3.5 and 3.0.

  FIG. 3 shows the low-rate discharge duration on the horizontal axis, and the low-rate discharge duration becomes longer with the S-element content up to 5000 μmol / g. However, the low-rate discharge duration was shortened when the S element content was over 6000 μmol / g. The larger the volume ratio, the longer the low rate discharge duration, but the difference in duration between the volume ratios 3.0 and 3.5 was small.

  Table 4 shows the low-temperature high-rate discharge duration after high-temperature overcharge, taking a volume ratio of 3.0 as an example. The higher the S element content, the better the low-temperature high-rate discharge performance after overcharging.

  Table 5 shows the median pore diameter of the negative electrode active material and the colloidal particle diameter of the organic shrunk agent in sulfuric acid corresponding to the electrolyte when the S element content is changed. Along with S element content, both the median pore size and colloidal particle size decreased. This suggests that the pore diameter of the negative electrode active material is reduced by reducing the colloidal particles of the organic shrinking agent dispersed in the pores of the negative electrode active material.

  Tables 6 and 7 and FIG. 4 show the effect of the volume ratio and S element content on the reaction resistance. The value when the S element content is 600 μmol / g (lignin) and the volume ratio is 3.0 is 100%. As shown. Table 7 shows comparative examples in which the S element content is 3000 μmol / g and 3500 μmol / g. The higher the S element content and the smaller the volume ratio, the lower the reaction resistance, especially between 1.8 and 1.1. Furthermore, the higher the S element content, the greater the slope of the reaction resistance with respect to the volume ratio of the electrolyte electrode plate. This suggests that by increasing the S element content, the resistance inside the negative electrode plate, which does not depend on the volume ratio, is reduced, and the ratio of resistance between the electrode plates to the reaction resistance is increased. The data in Table 6 and FIG. 4 suggest that the reaction resistance was decreased by setting the S element content to 4000 μmol / g or more and the volume ratio to 3.0 or less, and as a result, the low-temperature high-rate discharge performance was improved.

2 Electrode plate 4 Electrolyte 6 Battery case 8 Ear 10 Strap 12 Polar column

Claims (6)

  A lead-acid battery in which the negative electrode plate contains an organic shrinkage agent having an S element content of 3900 μmol / g or more and 6000 μmol / g or less, and the ratio of the volume of the electrolyte to the total volume of the positive and negative electrode plates is 3.0 or less.   The lead storage battery according to claim 1, wherein the organic shrunk agent has an S element content of 4300 μmol / g or more and 6000 μmol / g or less.   The lead acid battery according to claim 1 or 2, wherein the ratio of the volume of the electrolytic solution to the total volume of the positive and negative electrode plates is 1.1 or more and 3.0 or less.   4. The lead acid battery according to claim 3, wherein the organic shrunk agent is a synthetic polymer.   5. The lead acid battery according to claim 4, wherein the organic shrink-preventing agent is a condensate of bisphenols. 6. The lead acid battery according to claim 4, wherein the S element is contained as a sulfonic acid group or a sulfonyl group.