WO2022137700A1

WO2022137700A1 - Clad positive-electrode plate for lead storage battery, and lead storage battery

Info

Publication number: WO2022137700A1
Application number: PCT/JP2021/035798
Authority: WO
Inventors: 文也杉村
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2020-12-21
Filing date: 2021-09-29
Publication date: 2022-06-30
Also published as: JPWO2022137700A1

Abstract

This clad positive-electrode plate for a lead storage battery comprises a plurality of porous tubes, metal cores accommodated within the tubes, a positive electrode material with which the tubes are filled, and a current collector that connects the longitudinal-direction ends of a plurality of the metal cores lined up in a row. The positive electrode material contains organic fibers. The density of the positive electrode material is 3.75 g/cm³ or less. The positive electrode material satisfies at least one of a condition (a), in which the number of organic fibers per unit volume (cm³) of the positive electrode material is 400-15,000 (inclusive), and a condition (b), in which the ratio of the organic fibers occupying the positive electrode material is 0.013-0.5 vol% (inclusive).

Description

Clad type positive electrode plate for lead-acid battery and lead-acid battery

The present invention relates to a clad type positive electrode plate for a lead storage battery and a lead storage battery.

Lead-acid batteries are used for various purposes such as in-vehicle use, industrial use, and so on. The lead-acid battery includes a positive electrode plate, a negative electrode plate, and an electrolytic solution. As the positive electrode plate, a paste type positive electrode plate, a clad type positive electrode plate, or the like is used. Each electrode plate contains a current collector and an electrode material. From the viewpoint of imparting various functions, an additive may be added to a constituent member (for example, an electrode material) of a lead storage battery.

Patent Document 1 describes that the positive electrode material is a lead-acid battery having a density of 3.1 g / cm ³ or more and containing Sb element, and the organic shrinkage barrier of the negative electrode material contains S element of 3800 μmol / g or more. We are proposing a lead-acid battery that features.

In Patent Document 2, the negative electrode electrode material is gelled, held in a separator, or held in granular silica with a negative electrode plate containing an organic shrink-proofing agent having an S element content of 3500 μmol / g or more. We are proposing a lead-acid battery equipped with one or more of the electrolytes.

Patent Document 3 is characterized in that, in a positive electrode plate for a lead storage battery in which a positive electrode active material containing lead powder as a main component is filled in a positive electrode lattice, organic or glass short fibers and antimony are contained in the positive electrode active material. We are proposing a positive electrode plate for lead-acid batteries.

Patent Document 4 includes a positive electrode plate, a negative electrode plate, and an electrolytic solution, and the negative electrode electrode material of the negative electrode plate contains graphite or carbon fiber and a barium element of 1.1 mass% or more in terms of barium sulfate. We have proposed a lead storage battery characterized by containing tin element as the positive electrode material of the positive electrode plate.

It has also been proposed to adjust the density or specific surface area of the electrode material.

Patent Document 5 includes a positive electrode and a negative electrode, wherein the positive electrode has a positive electrode current collector and a positive electrode material held by the positive electrode current collector, and the negative electrode is a negative electrode current collector and the negative electrode. Proposed a lead storage battery having a negative electrode material held by a current collector, the positive electrode material having a specific surface area of 10 m ² / g or more, and the positive electrode material having a density of 3.8 g / cm ³ or more. is doing.

Patent Document 6 describes a positive electrode in which a positive electrode active material having a density of 3.8 to 5.0 g / cm ³ is held in a lattice body made of a lead alloy containing no antimony, and a positive electrode having a density of 1.20 to 1.28 g. We are proposing a sealed lead-acid battery with a sulfuric acid electrolyte of / ^cm3 .

Japanese Unexamined Patent Publication No. 2016-225113 Japanese Unexamined Patent Publication No. 2016-189297 Japanese Unexamined Patent Publication No. 2010-277799 International Publication No. 2018/025837 JP-A-2017-016970 Japanese Unexamined Patent Publication No. 2001-250589

In lead-acid batteries used in charge / discharge cycles including deep discharge, the temperature of the battery rises when charging / discharging is repeated for a long time. In a lead-acid battery provided with a clad type positive electrode plate, when the density of the positive electrode material is relatively low, when a charge / discharge cycle including deep discharge is performed at a high temperature (for example, a temperature of 75 ° C. or higher), a rapid voltage rise occurs during charging. It became clear that it could happen. For example, when a lead-acid battery is charged by the semi-constant voltage method, if a sudden voltage rise occurs during charging, it is recognized that the set voltage for charging has been reached early, and charging ends, and the charging is actually performed. It may be in short supply.

The first aspect of the present invention is a clad type positive electrode plate for a lead storage battery.
The positive electrode plate has a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and a plurality of core metal lengths arranged in a row. Equipped with a current collector that connects one end in the direction
The positive electrode material contains organic fibers and contains
The density of the positive electrode material is 3.75 g / cm ³ or less.
The present invention relates to a clad type positive electrode plate for a lead storage battery, wherein the number of the organic fibers per unit volume (cm ³ ) of the positive electrode material is 400 or more and 15,000 or less.

The second aspect of the present invention is a clad type positive electrode plate for a lead storage battery.
The positive electrode plate has a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and a plurality of core metal lengths arranged in a row. Equipped with a current collector that connects one end in the direction
The positive electrode material contains organic fibers and contains
The density of the positive electrode material is 3.75 g / cm ³ or less.
The present invention relates to a clad type positive electrode plate for a lead storage battery, wherein the ratio of the organic fiber to the positive electrode electrode material is 0.013% by volume or more and 0.5% by volume or less.

The third aspect of the present invention is a lead storage battery.
The lead-acid battery comprises at least one group of plates and an electrolytic solution.
The electrode plate group relates to a lead storage battery including at least one clad type positive electrode plate, at least one negative electrode plate, and a separator interposed between the clad type positive electrode plate and the negative electrode plate.

It is possible to reduce the voltage rise during charging when a lead storage battery equipped with a clad type positive electrode plate is charged and discharged in a charge / discharge cycle including deep discharge at high temperature.

It is a perspective view schematically showing an example which removed the lid of the lead storage battery which concerns on embodiment of this invention. It is a front view of the lead storage battery of FIG. It is a schematic cross-sectional view when the cross section in the IIB-IIB line of FIG. 1A is seen from the direction of an arrow. It is a graph which shows the relationship between the voltage rise occurrence rate of Table 1 and the density of a positive electrode material. It is a graph which shows the relationship between the voltage rise occurrence rate of Table 2 and the number of organic fibers. It is a graph which shows the relationship between the voltage rise occurrence rate of Table 2 and the ratio of an organic fiber. It is a graph which shows the relationship between the voltage rise occurrence rate of Table 3 and the specific gravity of an organic fiber. It is a graph which shows the relationship between the voltage rise occurrence rate of Table 3 and the oxygen element content of an organic fiber. It is a graph which shows the relationship between the initial capacity of Table 4 and the number of organic fibers. It is a graph which shows the relationship between the initial capacity of a table 4 and the ratio of an organic fiber.

In a lead-acid battery used in a charge / discharge cycle including deep discharge, the temperature of the battery becomes high (for example, a temperature of 75 ° C or higher) when charging / discharging is repeated for a long time. This is because, during charging, it tends to be in an overcharged state, which causes heat generation, and also during discharging, the resistance increases with deep discharge, so that heat generation increases.

It has been clarified that in a lead-acid battery provided with a clad type positive electrode plate, when the density of the positive electrode material is 3.75 g / cm ³ or less, when charging / discharging including deep discharge is performed at a high temperature, a rapid voltage rise occurs. rice field. The problem of such voltage rise is a new problem that has not been known so far. The clad type positive electrode plate includes, for example, a plurality of porous tubes, a core metal housed in the tube, and a positive electrode material filled in the tube. When the density of the positive electrode material is small, sulfate ions easily invade the inside of the positive electrode material. Although the details of the mechanism are not clear, the action of sulfate ions that have penetrated into the core causes ions and the like derived from the components contained in the core metal to diffuse into the positive electrode material, forming some kind of resistance component. It is considered that the above voltage rise occurs.

Lead-acid batteries may be charged by the semi-constant voltage method. In the quasi-constant voltage method, charging is performed while detecting the voltage of the lead storage battery (specifically, the terminal voltage). More specifically, when the battery voltage at the initial stage of charging is low, the charging current is large, charging proceeds, and when the battery voltage rises, the charging current decreases, and when the battery voltage reaches the set value, charging ends. In such a charging method, if the above-mentioned sudden voltage rise occurs during charging, it is mistakenly recognized that the battery voltage has reached the set value even though the charging has not actually progressed, and the charging is completed. May be done. Since the lead-acid battery that has been charged is actually in an insufficient charge state, it is difficult to operate the lead-acid battery for a long time even if it is mounted on a device or equipment.

In view of the above, the lead-acid battery according to each of the first side surface and the second side surface of the present invention includes at least one electrode plate group and an electrolytic solution. The electrode plate group includes at least one clad type positive electrode plate, at least one negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate. The positive electrode plate is formed by a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and one end of a plurality of core metal pieces arranged in a row in the length direction. It is equipped with a current collector for connecting the above. The positive electrode material contains organic fibers. The density of the positive electrode material is 3.75 g / cm ³ or less.

In the lead storage battery according to the first aspect, (a) the number of organic fibers per unit volume (cm ³ ) of the positive electrode material is 400 or more and 15,000 or less.

In the lead storage battery according to the second aspect, (b) the ratio of organic fibers to the positive electrode material is 0.013% by volume or more and 0.5% by volume or less.

In the lead-acid battery according to the first side surface and the second side surface, even if the density of the positive electrode material is 3.75 g / cm ³ or less, charging is performed at a high temperature (for example, 75 ° C.) in a charge / discharge cycle including deep discharge. It is possible to reduce the voltage rise at the time. Therefore, the rate of occurrence of voltage rise in the lead storage battery can be significantly reduced. Such an effect can be obtained by containing organic fibers in the positive electrode material so as to satisfy the above conditions (a) or (b), and even if the density of the positive electrode material is low, the organic fibers can be used. This is probably because the movement of ions in the positive electrode material is hindered. More specifically, it is considered that the invasion of sulfate ions into the vicinity of the core metal is alleviated. Furthermore, even if sulfate ions reach the vicinity of the core metal and the components contained in the core metal elute, the movement of ions derived from these components into the positive electrode material is hindered and diffusion into the entire positive electrode material is prevented. It is thought that it will be reduced. It is considered that the above voltage rise is reduced by reducing the formation of the resistance component in the positive electrode material.

In the present specification, the voltage increase during charging when charging / discharging in a charge / discharge cycle including deep discharge at a high temperature (for example, 75 ° C.) is simply referred to as “voltage increase in high temperature deep discharge cycle”. There is.

On the other hand, when the density of the positive electrode material exceeds 3.75 g / cm ³ in the clad type positive electrode plate, the voltage increase in the high temperature deep discharge cycle does not matter even if the positive electrode material does not contain organic fibers. That is, it can be said that the voltage increase in the high temperature deep discharge cycle is a problem peculiar to the case where the density of the positive electrode material is 3.75 g / cm ³ or less in the clad type positive electrode plate. In the first aspect and the second aspect of the present invention, such a specific problem can be solved by the condition (a) or (b).

The present invention also includes a clad type positive electrode plate for a lead storage battery that satisfies the condition (a) or (b). Each of the clad type positive electrode plates for lead storage batteries according to the third side surface and the fourth side surface of the present invention has a plurality of porous tubes, a core metal housed in the tubes, and a positive electrode material filled in the tubes. And a current collector that connects one end of a plurality of cores arranged in a row in the length direction. The positive electrode material contains organic fibers. The density of the positive electrode material is 3.75 g / cm ³ or less. The clad type positive electrode plate for a lead storage battery according to the third side surface satisfies the above condition (a). The clad type positive electrode plate for a lead storage battery according to the fourth side surface satisfies the above condition (b). By using such a clad type positive electrode plate for a lead storage battery, the above-mentioned effects described for the first side surface or the second side surface can be obtained.

Each of the first side surface and the third side surface may satisfy the condition (b) in addition to the condition (a). In this case, the voltage rise in the high temperature deep discharge cycle can be reduced more effectively.

The number of organic fibers per unit volume (cm ³ ) of the positive electrode material may be 800 or more. Further, the ratio of the organic fiber to the positive electrode material may be 0.026% by volume or more. In these cases, the rate of occurrence of voltage rise in the high temperature deep discharge cycle can be further reduced.

The number of organic fibers per unit volume (cm ³ ) of the positive electrode material may be 10,000 or less. Further, the ratio of the organic fiber to the positive electrode material may be 0.32% by volume or less. In these cases, in the positive electrode material, the decrease in the binding force is suppressed and the cracks are reduced, so that it is easy to secure a higher initial capacity.

The organic fiber preferably contains a fiber having a specific gravity of 1.2 or more. In this case, the rate of occurrence of voltage rise in the high temperature deep discharge cycle can be further reduced. It is considered that this is because the fibers are more likely to be uniformly dispersed in the entire positive electrode material, and the movement of ions in the positive electrode material is further restricted.

The organic fiber contains an oxygen element, and the content of the oxygen element in the organic fiber is preferably 10,000 μmol / g or more. In this case, the rate of occurrence of voltage rise in the high temperature deep discharge cycle can be further reduced. When the organic fiber contains a large amount of oxygen elements, the organic fiber tends to hydrogen bond with water molecules. This makes it easier for the organic fibers to be more evenly dispersed throughout the positive electrode material, and the movement of ions in the positive electrode material is further restricted by the organic fibers, resulting in a voltage rise in the high temperature deep discharge cycle. It is believed that the rate will be further reduced. It was

The content of oxygen element in the organic fiber may be 35,000 μmol / g or less. In this case, even if it is exposed to the positive electrode potential, oxidative decomposition of the organic fiber is suppressed, so that high durability can be ensured.

The organic fiber preferably contains at least one selected from the group consisting of polyester fiber, acetalized polyvinyl alcohol fiber, polyurethane fiber, and cellulose fiber. These organic fibers have an appropriate specific gravity, and are easily dispersed more uniformly over the entire positive electrode material. Therefore, it is considered that the movement of ions in the positive electrode electrode material is further restricted by the organic fiber, so that the occurrence rate of the voltage increase in the high temperature deep discharge cycle is further reduced.

The density of the positive electrode material is preferably 3.7 g / cm ³ or less. In this case, the rate of occurrence of voltage rise in the high temperature deep discharge cycle is further increased, but even in such a range, the positive electrode electrode so as to satisfy at least one of the above conditions (a) and (b). Since the material contains organic fibers, the occurrence rate of voltage rise in the high temperature deep discharge cycle can be reduced.

From the viewpoint of easily securing a higher discharge capacity, the density of the positive electrode material is preferably 3.3 g / cm ³ or more.

The lead-acid battery may be either a control valve type (sealed type) lead-acid battery (VRLA type lead-acid battery) or a liquid type (vent type) lead-acid battery.

In the present specification, the density of the positive electrode material, the number of organic fibers per unit volume, the ratio of the organic fibers to the positive electrode material, the specific gravity of the organic fibers, and the content of the oxygen element in the organic fibers are in a fully charged state. It is required for the positive electrode plate taken out from the lead storage battery of.

(Explanation of terms)
(Positive electrode material)
The clad type positive electrode plate consists of a plurality of porous tubes, a core metal (spine) housed in each tube, a positive electrode material filled in the tube, and a plurality of core metal pieces arranged in a row. It is provided with a current collector that connects one end in the length direction. The clad type positive electrode plate may further include a spine protector that connects a plurality of tubes. In the clad type positive electrode plate, the positive electrode material is a portion of the positive electrode plate excluding the tube, the core metal, the current collector, and the collective punishment. In the clad type positive electrode plate, the core metal and the current collector may be collectively referred to as a positive electrode current collector. A member such as a mat may be attached to the positive electrode plate. Since such a member (also referred to as a sticking member) is used integrally with the positive electrode plate, it is included in the positive electrode plate. When the positive electrode plate includes a sticking member (mat, etc.), the positive electrode electrode material is a portion of the positive electrode plate excluding the tube, the positive electrode current collector, the collective punishment, and the sticking member.

(Density of positive electrode material)
The density of the positive electrode material is a density (g / cm ³ ) obtained by dividing the mass of the positive electrode material by the bulk volume of the positive electrode material obtained by the mercury intrusion method. The density is determined for a predetermined amount of unmilled positive electrode material collected from the positive electrode plate taken out from the lead storage battery. The positive electrode material at this time is collected from one tube located near the center of the positive electrode plate.

(Number of organic fibers per unit volume of positive electrode material)
The number of organic fibers per unit volume (cm ³ ) of the positive electrode material is obtained by dividing the number of organic fibers contained in the positive electrode material by the bulk volume (cm ³ ) of the positive electrode material obtained by the mercury intrusion method. It is a numerical value obtained by. The number of organic fibers per unit volume (cm ³ ) of the positive electrode material is determined for a predetermined amount of unground positive electrode material used for calculating the density.

(Ratio of organic fibers in positive electrode material)
The ratio of the organic fibers to the positive electrode material is the ratio (% by volume) of the total volume of the organic fibers contained in the positive electrode material to the bulk volume (cm ³ ) of the positive electrode material obtained by the mercury intrusion method. The ratio of organic fibers to the positive electrode material is determined for a predetermined amount of unground positive electrode material used for calculating the density.

(Fully charged)
The fully charged state of a liquid lead-acid battery is defined by the definition of JIS D 5301: 2019. More specifically, in a water tank at 25 ° C ± 2 ° C, charging is performed every 15 minutes with a current (A) 0.2 times the value described as the rated capacity (value whose unit is Ah). The state in which the lead-acid battery is charged is regarded as a fully charged state until the terminal voltage (V) of No. 1 or the electrolyte density converted into temperature at 20 ° C. shows a constant value with three valid digits three times in a row. In the case of a control valve type lead-acid battery, the fully charged state is 0.2 times the current (value with Ah as the unit) described in the rated capacity in the air tank at 25 ° C ± 2 ° C (the unit is Ah). In A), constant current constant voltage charging of 2.23 V / cell is performed, and the charging current at the time of constant voltage charging is 0.005 times the value (value with the unit being Ah) described in the rated capacity (A). When it becomes, charging is completed.

A fully charged lead-acid battery is a fully charged lead-acid battery. The lead-acid battery may be fully charged after the chemical conversion, immediately after the chemical conversion, or after a lapse of time from the chemical conversion (for example, after the chemical conversion, the lead-acid battery in use (preferably at the initial stage of use) is fully charged. May be). An initial use battery is a battery that has not been used for a long time and has hardly deteriorated.

(Vertical direction of lead-acid battery or lead-acid battery component)
In the present specification, the vertical direction of the lead-acid battery or the component of the lead-acid battery (plate, battery case, separator, etc.) means the vertical direction of the lead-acid battery in the state where the lead-acid battery is used. Each electrode plate of the positive electrode plate and the negative electrode plate is provided with an ear portion for connecting to an external terminal. In some lead-acid batteries, such as horizontal control valve type lead-acid batteries, the ears are provided so as to project laterally to the sides of the plate, but in many lead-acid batteries, the ears are usually made of the plate. It is provided so as to project upward at the top.

Hereinafter, the clad type positive electrode plate and the lead storage battery according to the embodiment of the present invention will be described for each of the main constituent requirements, but the present invention is not limited to the following embodiments.

[Clad type positive electrode plate]
The clad type positive electrode plate has a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and a plurality of core metal pieces arranged in a row in the length direction. It is provided with a current collector that connects one end. Further, the clad type positive electrode plate usually has a collective punishment for connecting a plurality of tubes.

(Positive electrode material)
The positive electrode material contains organic fibers. The positive electrode material usually contains a positive electrode active material (specifically, at least one of lead dioxide and lead sulfate) that develops a capacity by a redox reaction. The positive electrode material may contain other additives, if necessary.

The density of the positive electrode material is 3.75 g / cm ³ or less. In this case, there is a problem of voltage increase in the high temperature deep discharge cycle due to the inclusion of organic fibers in the positive electrode material, but by satisfying at least one of the above conditions (a) and (b), the high temperature deep discharge cycle occurs. It is possible to reduce the voltage rise in. The density of the positive electrode material may be 3.7 g / cm ³ or less. In this case, the rate of occurrence of voltage increase in the high temperature deep discharge cycle becomes higher, but even in this case, the voltage in the high temperature deep discharge cycle is satisfied by satisfying at least one of the above conditions (a) and (b). The rise can be reduced. From the viewpoint of easily securing a higher discharge capacity, the density of the positive electrode material is preferably 3.3 g / cm ³ or more.

The number of organic fibers per unit volume (cm ³ ) of the positive electrode material is 400 or more. From the viewpoint of further reducing the occurrence rate of voltage rise in the high temperature deep discharge cycle, the number of organic fibers per unit volume (cm ³ ) of the positive electrode material is preferably 800 or more. The number of organic fibers per unit volume (cm ³ ) of the positive electrode material is 15,000 or less, preferably 10,000 or less, and more preferably 7500 or less or 7200 or less. When the density of the positive electrode material becomes small, the binding force decreases and cracks tend to occur easily. However, when the number of organic fibers is in such a range, a relatively high binding force can be secured in the positive electrode material, and cracks are reduced, so that a higher initial capacity can be secured. These lower limit values and upper limit values can be arbitrarily combined.

The ratio of organic fibers to the positive electrode material is 0.013% by volume or more. From the viewpoint of further reducing the occurrence rate of voltage rise in the high temperature deep discharge cycle, the ratio of organic fibers is preferably 0.026% by volume or more. The ratio of the organic fiber is 0.5% by volume or less, preferably 0.32% by volume or less, and more preferably 0.25% by volume or less or 0.23% by volume or less. When the ratio of the organic fibers is in such a range, a relatively high binding force can be secured in the positive electrode material, and cracks are reduced, so that a higher initial capacity can be secured. These lower limit values and upper limit values can be arbitrarily combined.

The organic fiber preferably contains a fiber having a specific gravity of 1.2 or more (hereinafter, may be referred to as a first fiber). In this case, since the first fiber has high dispersibility, the rate of occurrence of voltage increase in the high temperature deep discharge cycle can be further reduced. From the viewpoint of further reducing the occurrence rate of voltage increase in the high temperature deep discharge cycle, the specific gravity of the first fiber is more preferably 1.25 or more or 1.26 or more. The specific gravity of the first fiber is, for example, 1.7 or less, and may be 1.6 or less or 1.5 or less. These lower limit values and upper limit values can be arbitrarily combined.

The organic fiber may contain a fiber other than the first fiber (hereinafter, may be referred to as a second fiber), but from the viewpoint of ensuring high dispersibility of the organic fiber, the organic fiber contained in the positive electrode electrode material. It is preferable that the ratio of the first fiber to the whole is high. The ratio of the first fiber to the total organic fibers contained in the positive electrode material is preferably 60% by volume or more, more preferably 75% by volume or more, still more preferably 90% by volume or more. The ratio of the first fiber to the total organic fiber is 100% by volume or less. The positive electrode material may contain only the first fiber as the organic fiber. The second fiber is an organic fiber having a specific gravity of less than 1.2 (for example, 0.8 or more and less than 1.2).

The organic fiber may contain an oxygen element. The content of the oxygen element in the organic fiber is, for example, 10,000 μmol / g or more, preferably 15,000 μmol / g or more, more preferably 17,000 μmol / g or more or 17,400 μmol / g or more, and 19000 μmol / g or more or 20,000 μmol / g or more. More preferably, it may be 20800 μmol / g or more. When the content of the oxygen element is in such a range, the organic fibers are easily hydrogen-bonded to water molecules, so that the dispersibility of the organic fibers in the positive electrode material can be further enhanced, and the voltage in the high temperature deep discharge cycle can be further improved. The rate of rise can be further reduced. The content of the oxygen element in the organic fiber is, for example, 50,000 μmol / g or less, and may be 40,000 μmol / g or less. From the viewpoint of ensuring higher durability of the organic fiber, the content of the oxygen element in the organic fiber is preferably 35,000 μmol / g or less. These lower limit values and upper limit values can be arbitrarily combined.

The average fiber diameter of the organic fiber is, for example, 1 μm or more, and may be 5 μm or more or 10 μm or more. When the average fiber diameter is in such a range, it is easy to secure higher dispersibility of the organic fiber in the positive electrode material. The average fiber diameter of the organic fiber is, for example, 50 μm or less, and may be 30 μm or less or 20 μm or less. When the average fiber diameter is in such a range, it is easy to secure higher conductivity of the positive electrode material. These lower limit values and upper limit values can be arbitrarily combined.

The average fiber length of the organic fiber is, for example, 0.1 mm or more, may be 0.5 mm or more or 1 mm or more, and may be 1.5 mm or more or 2 mm or more. When the average fiber length is in such a range, it is easy to secure higher dispersibility in the positive electrode material. The average fiber length of the organic fiber is, for example, 10 mm or less, and may be 6 mm or less. When the average fiber length is in such a range, higher dispersibility of the organic fiber can be ensured, and it is easy to secure higher conductivity of the positive electrode material. These lower limit values and upper limit values can be arbitrarily combined.

The average fiber diameter of the organic fiber is the average value of the maximum diameters of any 100 fibers of the organic fiber separated from the positive electrode material. The average fiber length of the organic fiber is an average value of the length of each of any 100 fibers of the organic fiber separated from the positive electrode material.

Examples of the organic fiber include polyester fiber, polyvinyl alcohol fiber (acetalized polyvinyl alcohol fiber, etc.), polyurethane fiber, acrylic fiber, polyacrylonitrile fiber, polyolefin fiber, polyvinyl chloride fiber, polystyrene fiber, polyamide fiber, and cellulose fiber. Be done. Cellulose fibers include not only cellulose fibers but also fibers made of cellulose derivatives (for example, cellulose ethers and cellulose esters), rayon and the like. The positive electrode material may contain one kind of these organic fibers, or may contain two or more kinds of these organic fibers. Polyester fiber, acetalized polyvinyl alcohol fiber, polyurethane fiber, and cellulose fiber are preferable, and polyester fiber, acetalized polyvinyl alcohol fiber, and the like, from the viewpoint of having an appropriate specific gravity and easily ensuring higher dispersibility in the positive electrode electrode material. And cellulose fibers are more preferred.

(others)
The core metal is made of, for example, a lead alloy. It is preferable to use a Pb—Sb based alloy for the core metal. The Pb-Sb-based alloy may contain at least one of arsenic, selenium, bismuth, and tin, if necessary.

The current collector is made of, for example, a lead alloy. It is preferable to use a Pb—Sb-based alloy for the current collector. The Pb-Sb-based alloy may contain at least one of arsenic, selenium, bismuth, and tin, if necessary.

The porous tube should be able to accommodate the core metal inside and hold the positive electrode material. Porous tubes are usually tubular fiber aggregates. As the tube-shaped fiber aggregate, a fiber aggregate obtained by knitting fibers into a tube shape may be used, or a tubular non-woven fabric or a woven fabric may be used. Examples of the fiber include an inorganic fiber (glass fiber and the like) and a resin fiber. However, the fibers are not limited to these. The porous tube may be heat-treated, if necessary. Further, in the porous tube, the tubular fiber aggregate may be impregnated with a resin.

The length of the tube may be selected according to the length of the core metal. The outer diameter and thickness of the tube are selected, for example, depending on the shape of the core metal or the application of the lead-acid battery.

The collective punishment is usually arranged at one end of the tube on the current collector side and the other end on the opposite side of the current collector. More specifically, in the length direction of the tube, one end of the tube on the current collecting portion side is usually fixed to the current collecting portion by an upper joint. The other end of the tube is sealed by a lower punishment. The upper joint is usually formed by integrally molding a resin so as to cover the upper part of the core metal and the current collector. The lower punishment is usually made of resin and is inserted into the opening at the other end of each tube. The current collector is usually formed with an ear for extracting electricity from the lead-acid battery.

The clad type positive electrode plate is not formed by accommodating a plurality of cores having one end in the length direction connected in a current collector in a plurality of tubes and filling the tubes with lead powder. It is formed by forming a chemical positive electrode plate. The order of accommodating the core metal and filling the lead powder is not particularly limited. More specifically, in the unchemical positive electrode plate, after accommodating each of the plurality of cores in the tube, one end of the plurality of tubes and the current collecting portion are fixed by the upper joint, and the other end of the tube is fixed. It is formed by filling a tube with a mixture containing lead powder, organic fibers and the like from the opening of the tube, and sealing the opening at the other end of the plurality of tubes with a lower joint. Lead powder contains at least lead monoxide. The lead powder may contain metallic lead. In addition, lead powder and lead tan may be used in combination.

The filling of the mixture in the tube may be either drywall or wet. For example, in the case of dry type, the dry mixture is filled in the tube as it is, and in the case of wet type, the slurry-like mixture is filled. The mixture contains, for example, lead powder, organic fibers and optionally additives. For example, a slurry-like mixture is prepared by mixing lead powder, organic fibers, water, sulfuric acid, and if necessary, additives and the like. From the viewpoint of easily ensuring higher dispersibility of the organic fiber in the positive electrode material, it is preferable to use a slurry-like mixture. In particular, when the oxygen element content of the organic fiber is in the above range, the organic fiber can be more uniformly dispersed in the slurry-like mixture by the action of water.

The unchemical positive electrode plate is further chemicalized. Lead dioxide is produced by the chemical formation. Chemical formation can be performed, for example, by charging the electrode plate group in a state where the electrode plate group including the unchemical clad type positive electrode plate is immersed in an electrolytic solution containing sulfuric acid in the electric tank of a lead storage battery. can. Such chemical formation is called electric tank chemical formation. However, the chemical conversion of the positive electrode plate may be performed before assembling the electrode plate group, not limited to the case of the electric tank chemical conversion.

(Measurement of density of positive electrode material and analysis of positive electrode material and its constituents)
Hereinafter, a method for measuring the density of the positive electrode material and a method for analyzing the positive electrode material or its constituent components will be described. Prior to measurement or analysis, a fully charged lead-acid battery is disassembled to obtain a positive electrode plate to be analyzed. The obtained positive electrode plate is washed with water and dried to remove the electrolytic solution in the positive electrode plate. Next, the positive electrode material is separated from the positive electrode plate to obtain an unground sample (Sample A). Sample A is pulverized into powder as needed and subjected to analysis.

(1) Measurement of Density of Positive Electrode Material The density (bulk density) of unground sample A is determined by a mercury intrusion method using a mercury porosimeter. More specifically, first, a predetermined amount of uncrushed sample A is collected and the mass is measured. After putting this sample A into the measuring container of the mercury porosimeter and exhausting it under reduced pressure, the sample A is filled with mercury at a pressure of 0.5 psia or more and 0.55 psia or less (≈3.45 kPa or more and 3.79 kPa or less). The density of the positive electrode electrode material is obtained by measuring the bulk volume and dividing the measured mass of the sample A by the bulk volume. The volume obtained by subtracting the mercury injection volume from the volume of the measuring container is defined as the bulk volume. As the mercury porosimeter, an automatic porosimeter (Autopore IV9505) manufactured by Shimadzu Corporation is used.

(2) Analysis of organic fibers (2-1) Separation of organic fibers 5 g of sample A whose bulk volume was measured in (1) above was collected, and 50 mL of nitric acid having a concentration of 20% by mass and 300 g / L of hydrogen peroxide solution were collected. Add 20 mL. The resulting mixture is heated at 80 ° C. ± 5 ° C. until the lead component is completely dissolved. The solid content is separated by filtering the resulting mixture. The obtained solid content is dispersed in water to prepare a dispersion. A sieve is used to separate the organic fibers from the dispersion and the components other than the organic fibers.

(2-2) Number and ratio of organic fibers Measure the number of all organic fibers separated in (2-1) above, and divide by the bulk volume (cm ³ ) of the positive electrode material measured in (1). Therefore, the number of organic fibers per unit volume of the positive electrode material can be obtained.

(2-3) Specific gravity of organic fiber A predetermined amount of the organic fiber separated in (2-1) above is collected, and the specific gravity of the fiber is determined by the density gradient tube method in accordance with JIS K7112-1999.

The total volume of the organic fibers contained in the sample A collected from the specific gravity of the fibers thus obtained, the number of all the organic fibers calculated in (2-2) above, and the mass of all the organic fibers. Find (cm ³ ). The ratio (% by volume) of the total volume (cm ³ ) of the organic fiber to the bulk volume (cm ³ ) of the positive electrode material measured in (1) is determined. This ratio corresponds to the ratio (volume%) of organic fibers in the positive electrode material.

(2-4) Content of oxygen element in organic fiber A predetermined amount of the organic fiber separated in (2-1) above is collected. The collected organic fiber is subjected to CHN / O elemental analysis using an organic trace analyzer to determine the amount of oxygen (μmol / g) per 1 g of the organic fiber. Examples of the organic trace analyzer include Exeter Analytical, Inc. CE-440 manufactured by the company is used.

(2-5) Types of organic fibers The thermal decomposition GC-MS spectrum of the organic fibers separated in (2-1) above, and the infrared spectroscopic spectrum of the solution obtained by dissolving the organic fibers in a predetermined solvent, ultraviolet rays. The type (material) of the organic fiber is specified by combining the information obtained from the visible absorption spectrum, the NMR spectrum, and the like.

(2-6) Average fiber diameter and average fiber length of organic fibers Select any 100 fibers from the organic fibers separated in (2-1) above, measure the maximum diameter of each fiber, and average them. The average fiber diameter of the organic fiber can be obtained.

From the organic fibers separated in (2-1) above, select any 100 fibers and measure the length of each fiber. The length of the fiber is the length of the center line of the fiber. By averaging the measured fiber lengths, the average fiber length of organic fibers can be obtained.

(Negative electrode plate)
The negative electrode plate includes, for example, a negative electrode material and a current collector that holds the negative electrode material. The negative electrode material is a portion obtained by removing the current collector from the negative electrode plate. Members such as mats and pacing papers may be attached to the negative electrode plate. Since such a member (also referred to as a sticking member) is used integrally with the negative electrode plate, it is included in the negative electrode plate. When the negative electrode plate includes a sticking member (mat, pacing paper, etc.), the negative electrode electrode material is a portion of the negative electrode plate excluding the current collector and the sticking member.

If a separator and a mat are used together in the electrode plate group, or if a mat mainly composed of non-woven fabric is attached to the negative electrode plate, the thickness of the negative electrode plate shall be the thickness including the mat. This is because the mat is used integrally with the negative electrode plate. However, if a mat is attached to the separator, the thickness of the mat is included in the thickness of the separator.

The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead sheet or a lead alloy sheet. Examples of the processing method include expanding processing and punching processing. It is preferable to use a grid-shaped current collector as the negative electrode current collector because it is easy to support the negative electrode material.

The lead alloy used for the negative electrode current collector may be any of Pb—Sb-based alloys, Pb-Ca-based alloys, and Pb-Ca—Sn-based alloys. These leads or lead alloys may further contain, as an additive element, at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu and the like. The negative electrode current collector may include a surface layer. The composition of the surface layer and the inner layer of the negative electrode current collector may be different. The surface layer may be formed on a part of the negative electrode current collector. The surface layer may be formed on the selvage portion of the negative electrode current collector. The surface layer of the selvage may contain Sn or Sn alloy.

The negative electrode electrode material contains a negative electrode active material (specifically, lead or lead sulfate) whose capacity is developed by a redox reaction as an essential component, and is an organic shrinkage inhibitor, a carbonaceous material, barium sulfate, a fiber (resin fiber, etc.). May contain additives such as. Additives are not limited to these. The negative electrode active material in the charged state is spongy lead, but the unchemical negative electrode plate is usually produced by using lead powder. The lead powder preferably contains at least lead monoxide. The lead powder may further contain metallic lead.

The organic shrinkage proofing agent is an organic compound among compounds having a function of suppressing the shrinkage of lead, which is a negative electrode active material, when the lead storage battery is repeatedly charged and discharged. Organic shrinkage proofing agents are usually roughly classified into lignin compounds and synthetic organic shrinkage proofing agents. It can be said that the synthetic organic shrinkage proofing agent is an organic shrinkage proofing agent other than the lignin compound. Examples of the organic shrinkage proofing agent contained in the negative electrode electrode material include a lignin compound and a synthetic organic shrinkage proofing agent. The negative electrode electrode material may contain one kind of organic shrinkage proofing agent, or may contain two or more kinds of organic shrinkage proofing agents.

Examples of the lignin compound include lignin and lignin derivatives. Examples of the lignin derivative include lignin sulfonic acid or a salt thereof (alkali metal salt (sodium salt, etc.), etc.).

The synthetic organic shrinkage proofing agent is an organic polymer containing an element of sulfur. Examples of the synthetic organic shrinkage proofing agent include a condensate of an aldehyde compound (aldehyde or a condensate thereof (for example, formaldehyde)) of a compound having a sulfur-containing group and an aromatic ring. However, synthetic organic shrinkage proofing agents are not limited to this. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group, which is a stable form, is preferable. The sulfonic acid group may be present in acid form or may be present in salt form such as Na salt.

The content of the organic shrink-proofing agent contained in the negative electrode electrode material is, for example, 0.01% by mass or more, and may be 0.05% by mass or more. The content of the organic shrinkage proofing agent is, for example, 1.0% by mass or less, and may be 0.5% by mass or less. Here, the content of the organic shrinkage-proofing agent contained in the negative electrode electrode material is the content in the negative electrode material collected by the method described later from a prefabricated lead-acid battery in a fully charged state. These lower limit values and upper limit values can be arbitrarily combined.

As the carbonaceous material contained in the negative electrode electrode material, carbon black, graphite, hard carbon, soft carbon, etc. can be used. Examples of carbon black include acetylene black, furnace black, and lamp black. Furness Black also includes Ketjen Black (trade name). The graphite may be any carbonaceous material containing a graphite-type crystal structure, and may be either artificial graphite or natural graphite. The negative electrode material may contain one kind of carbonaceous material, or may contain two or more kinds of carbonaceous material.

The content of the carbonaceous material in the negative electrode electrode material is, for example, 0.05% by mass or more, and may be 0.10% by mass or more. The content of the carbonaceous material is, for example, 5% by mass or less, and may be 3% by mass or less. These lower limit values and upper limit values can be arbitrarily combined.

(Barium sulfate)
The content of barium sulfate in the negative electrode electrode material is, for example, 0.05% by mass or more, and may be 0.10% by mass or more. The content of barium sulfate in the negative electrode electrode material is, for example, 3% by mass or less, and may be 2% by mass or less. These lower limit values and upper limit values can be arbitrarily combined.

The negative electrode plate can be formed by applying or filling a negative electrode paste to a negative electrode current collector, aging and drying to produce an unchemical negative electrode plate, and then forming an unchemical negative electrode plate. The negative electrode paste is prepared by adding water and sulfuric acid (or an aqueous solution of sulfuric acid) to, for example, lead powder and at least one selected from the group consisting of an organic shrinkage proofing agent, a carbonaceous material, barium sulfate, and other additives, if necessary. In addition, it is produced by kneading. At the time of aging, it is preferable to ripen the unchemical negative electrode plate at a temperature higher than room temperature and high humidity.

Chemical formation can be performed by charging the electrode plate group in a state where the electrode plate group including the unchemical negative electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group. The formation produces spongy lead.

(Analysis of constituents of negative electrode material)
The method of analyzing the constituent components of the negative electrode material will be described below. Prior to measurement or analysis, a fully charged lead-acid battery is disassembled to obtain a negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water to remove sulfuric acid from the negative electrode plate. Wash with water by pressing the pH test paper against the surface of the negative electrode plate washed with water until it is confirmed that the color of the test paper does not change. However, the time for washing with water shall be within 2 hours. The negative electrode plate washed with water is dried at 60 ± 5 ° C. for about 6 hours in a reduced pressure environment. If the negative electrode plate contains a sticking member after drying, the sticking member is removed by peeling. Next, a sample (hereinafter referred to as sample B) is obtained by separating the negative electrode material from the negative electrode plate. Sample B is pulverized as needed and subjected to analysis.

(1) Analysis of organic shrinkage-proofing agent (1-1) Qualitative analysis of organic shrinkage-proofing agent in negative electrode material The crushed sample B is immersed in a 1 mol / L sodium hydroxide aqueous solution to extract the organic shrinkage-proofing agent. The insoluble components are then filtered off the extract, the resulting solution is desalted, then concentrated and dried. Desalination is performed using a desalting column, by passing the solution through an ion exchange membrane, or by placing the solution in a dialysis tube and immersing it in distilled water. By drying this, a powder sample of an organic shrinkage proofing agent (hereinafter referred to as sample C) can be obtained.

The infrared spectroscopic spectrum measured using the sample C of the organic shrinkage proofing agent thus obtained, the ultraviolet visible absorption spectrum measured by diluting the sample C with distilled water or the like, and the sample C being used as heavy water or the like. Combining the NMR spectrum of the solution obtained by dissolving in a predetermined solvent or the information obtained from thermal decomposition GC-MS or the like capable of obtaining information on the individual compounds constituting the substance, the organic shrinkage proofing agent Identify the type.

(1-2) Quantification of the content of the organic shrinkage proofing agent in the negative electrode electrode material In the same manner as in (1-1) above, a solution is obtained after removing insoluble components from the extract containing the organic shrinkage proofing agent by filtration. The ultraviolet-visible absorption spectrum of the obtained solution is measured. The content of the organic shrinkage proofing agent in the negative electrode electrode material is determined by using the peak intensity characteristic of the organic shrinkage proofing agent and the calibration curve prepared in advance.

When a lead-acid battery having an unknown content of the organic shrinkage proof is obtained and the content of the organic shrinkage proofing agent is measured, the structural formula of the organic shrinkage proofing agent cannot be specified exactly, so that the same organic shrinkage proofing is applied to the calibration curve. The agent may not be available. In this case, calibration is performed using an organic shrink-proof agent extracted from the negative electrode of the battery and a separately available organic polymer having a similar shape in the ultraviolet-visible absorption spectrum, infrared spectroscopic spectrum, NMR spectrum, and the like. By creating a line, the content of the organic shrink-proofing agent is measured using the ultraviolet-visible absorption spectrum.

(2) Quantification of carbonaceous material and barium sulfate To 10 g of crushed sample B, 50 mL of nitric acid having a concentration of 20% by mass is added and heated for about 20 minutes to dissolve the lead component as lead ions. The obtained solution is filtered to filter out solids such as carbonaceous materials and barium sulfate.

After the obtained solid content is dispersed in water to form a dispersion liquid, a carbonaceous material and components other than barium sulfate (for example, a reinforcing material) are removed from the dispersion liquid using a sieve. Next, the dispersion liquid is suction-filtered using a membrane filter whose mass has been measured in advance, and the membrane filter is dried together with the filtered sample in a dryer at 110 ° C. ± 5 ° C. The filtered sample is a mixed sample of carbonaceous material and barium sulfate. The mass of the sample C (M _m ) is measured by subtracting the mass of the membrane filter from the total mass of the dried mixed sample (hereinafter referred to as sample C) and the membrane filter. Then, the sample C is put into a crucible together with a membrane filter and incinerated at 1300 ° C. or higher. The remaining residue is barium oxide. The mass of barium oxide is converted into the mass of barium sulfate to obtain the mass of barium sulfate ( _MB ). The mass of the carbonaceous material is calculated by subtracting the mass MB from the mass _M _m .

(Separator)
A separator can be arranged between the negative electrode plate and the positive electrode plate. As the separator, at least one selected from a non-woven fabric and a microporous membrane is used.

Nonwoven fabric is a mat that is entwined without weaving fibers, and is mainly composed of fibers. In the non-woven fabric, for example, 60% by mass or more of the non-woven fabric is formed of fibers. As the fiber, glass fiber, polymer fiber (polyolefin fiber, acrylic fiber, polyester fiber (polyethylene terephthalate fiber, etc.), etc.), pulp fiber, and the like can be used. Of these, glass fiber is preferable. The nonwoven fabric may contain components other than fibers (for example, acid-resistant inorganic powder, polymer as a binder) and the like.

On the other hand, the microporous film is a porous sheet mainly composed of components other than fiber components. For example, a composition containing a pore-forming agent is extruded into a sheet and then the pore-forming agent is removed to form pores. It is obtained by. The microporous membrane is preferably composed of a material having acid resistance, and a microporous membrane mainly composed of a polymer component is preferable. As the polymer component, polyolefin (polyethylene, polypropylene, etc.) is preferable. Examples of the pore-forming agent include at least one selected from the group consisting of polymer powders and oils.

The separator may be composed of, for example, only a non-woven fabric or only a microporous membrane. Further, the separator may be a laminate of a non-woven fabric and a microporous film, a material obtained by laminating different or similar materials, or a material in which irregularities are engaged with different or similar materials, as required.

The separator may be in the shape of a sheet or in the shape of a bag. A sheet-shaped separator may be sandwiched between the positive electrode plate and the negative electrode plate. Further, the electrode plate may be arranged so as to sandwich the electrode plate with one sheet-shaped separator in a bent state. In this case, the positive electrode plate sandwiched between the bent sheet-shaped separators and the negative electrode plate sandwiched between the bent sheet-shaped separators may be overlapped, and one of the positive electrode plate and the negative electrode plate may be sandwiched between the bent sheet-shaped separators. , May be overlapped with the other electrode plate. Further, the sheet-shaped separator may be bent in a bellows shape, and the positive electrode plate and the negative electrode plate may be sandwiched between the bellows-shaped separators so that the separator is interposed between them. When using a separator bent in a bellows shape, the separator may be arranged so that the bent portion is along the horizontal direction of the lead storage battery (for example, the bent portion is parallel to the horizontal direction), or along the vertical direction. (For example, the separator may be arranged so that the bent portion is parallel to the vertical direction). In the bellows-shaped separator, recesses are alternately formed on both main surface sides of the separator. Since the ear portion is usually formed on the upper part of the positive electrode plate and the negative electrode plate, when the separator is arranged so that the bent portion is along the horizontal direction of the lead storage battery, the positive electrode plate is formed only in the concave portion on one main surface side of the separator. And a negative electrode plate is arranged (that is, a double separator is interposed between the adjacent positive electrode plate and the negative electrode plate). When the separator is arranged so that the bent portion is along the vertical direction of the lead storage battery, the positive electrode plate can be accommodated in the recess on one main surface side and the negative electrode plate can be accommodated in the recess on the other main surface side (that is,). , The separator can be in a single interposition between the adjacent positive electrode plate and the negative electrode plate). When a bag-shaped separator is used, the bag-shaped separator may accommodate a positive electrode plate or a negative electrode plate.

(Electrolytic solution)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary.
The electrolytic solution may contain the above-mentioned polymer compound.

The electrolytic solution may contain a cation (for example, a metal cation) and / or an anion (for example, an anion other than the sulfate anion (for example, a phosphate ion)), if necessary. Examples of the metal cation include at least one selected from the group consisting of Na ion, Li ion, Mg ion, and Al ion.

The specific gravity of the electrolytic solution in a fully charged lead storage battery at 20 ° C. is, for example, 1.20 or more, and may be 1.25 or more. The specific gravity of the electrolytic solution at 20 ° C. is 1.35 or less, and may be 1.32 or less. These lower limit values and upper limit values can be arbitrarily combined.

(others)
The lead-acid battery can be obtained by a manufacturing method including a step of accommodating a group of plates and an electrolytic solution in an electric tank. The electrode plate group is assembled by laminating the positive electrode plate, the negative electrode plate, and the separator so that the separator is interposed between the positive electrode plate and the negative electrode plate prior to the accommodation in the electric tank. The positive electrode plate, the negative electrode plate, the electrolytic solution, and the separator are each prepared prior to assembling the electrode plate group. The method for manufacturing a lead-acid battery may include, if necessary, a step of forming at least one of a positive electrode plate and a negative electrode plate after a step of accommodating a group of electrode plates and an electrolytic solution in an electric tank. One battery case usually contains one group of plates. If necessary, one electric tank may contain two or more groups of plates. The lead-acid battery may be provided with one battery case containing a group of plates and an electrolytic solution, or may be provided with two or more lead-acid batteries. When two or more electric tanks containing a group of plates and an electrolytic solution are provided, each group of plates is usually connected in series.

Each electrode plate in the electrode plate group may be one plate or two or more plates. When the electrode plate group includes two or more positive electrode plates, the density of the positive electrode electrode material is in the above range for at least one positive electrode plate, and at least one of the above conditions (a) and (b) is satisfied. If this is done, the generation of resistance components is reduced for the positive electrode plates, and the effect of reducing the occurrence rate of voltage increase in the high temperature deep discharge cycle in the lead storage battery can be obtained according to the number of such positive electrode plates. From the viewpoint of further reducing the occurrence rate of voltage rise in the high temperature deep discharge cycle, 50% or more (more preferably 80% or more or 90% or more) of the number of positive electrode plates included in the electrode plate group is the above condition. It is preferable that the positive electrode plate satisfies the above. Among the positive electrode plates included in the electrode plate group, the ratio of the positive electrode plates having the density of the positive electrode electrode material in the above range and satisfying the above conditions is 100% or less. It is particularly preferable that all of the positive electrode plates included in the electrode plate group have a density of the positive electrode electrode material in the above range and satisfy the above conditions.

When the lead-acid battery has two or more electrode plates, at least a part of the electrode plates has a positive electrode plate in which the density of the positive electrode material is in the above range and satisfies the above conditions. All you have to do is prepare. From the viewpoint of further reducing the occurrence rate of voltage rise in the high temperature deep discharge cycle, 50% or more (more preferably 80% or more or 90% or more) of the number of electrode plates contained in the lead storage battery is the positive electrode material. It is preferable to include a group of electrode plates including a positive electrode plate having a density of the above-mentioned range and satisfying the above-mentioned conditions. Among the electrode plate groups included in the lead storage battery, the ratio of the electrode plate group including the electrode plate group including the positive electrode plate having the density of the positive electrode electrode material in the above range and satisfying the above conditions is 100% or less. be. It is preferable that all of the electrode plates included in the lead storage battery are provided with a positive electrode plate in which the density of the positive electrode electrode material is in the above range and the above conditions are satisfied.

FIG. 1 is a perspective view schematically showing an example in which the lid of the lead storage battery according to the embodiment of the present invention is removed. 2A is a front view of the lead storage battery of FIG. 1, and FIG. 2B is a schematic cross-sectional view taken along the line IIB-IIB of FIG. 2A when viewed from the direction of an arrow.
The lead-acid battery 1 includes an electric tank 10 that houses the electrode plate group 11 and the electrolytic solution 12. The electrode plate group 11 is configured by laminating a plurality of negative electrode plates 2 and a clad type positive electrode plate 3 via a separator 4. Here, a state in which the sheet-shaped separator 4 is sandwiched between the negative electrode plate 2 and the clad type positive electrode plate 3, but the form of the separator is not particularly limited.

At the upper part of each of the plurality of negative electrode plates 2, an ear portion (not shown) for collecting electricity is provided so as to project upward. An ear portion (not shown) for collecting electricity is also provided on the upper portion of each of the plurality of clad type positive electrode plates 3 so as to project upward. The ears of the negative electrode plate 2 are connected to each other by the negative electrode strap 5a and integrated. Similarly, the ears of the clad type positive electrode plate 3 are also connected and integrated by the positive electrode strap 5b. The lower end of the negative electrode column 6a is fixed to the upper part of the negative electrode strap 5a, and the lower end of the positive electrode column 6b is fixed to the upper part of the positive electrode strap 5b.

The clad type positive electrode plate for a lead storage battery and the lead storage battery according to one aspect of the present invention are collectively described below.

(1) A clad type positive electrode plate for a lead storage battery.
The positive electrode plate has a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and a plurality of core metal lengths arranged in a row. Equipped with a current collector that connects one end in the direction
The positive electrode material contains organic fibers and contains
The density of the positive electrode material is 3.75 g / cm ³ or less.
A clad type positive electrode plate for a lead storage battery, wherein the number of the organic fibers per unit volume (cm ³ ) of the positive electrode material is 400 or more and 15,000 or less.

(2) In the above (1), the number of the organic fibers per unit volume of the positive electrode material may be 800 or more.
(3) In the above (1) or (2), the number of the organic fibers per unit volume of the positive electrode material may be 10,000 or less, 7500 or less, or 7200 or less.

(4) In any one of the above (1) to (3), the ratio of the organic fiber to the positive electrode material may be 0.013% by volume or more and 0.5% by volume or less.

(5) A clad type positive electrode plate for a lead storage battery.
The positive electrode plate has a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and a plurality of core metal lengths arranged in a row. Equipped with a current collector that connects one end in the direction
The positive electrode material contains organic fibers and contains
The density of the positive electrode material is 3.75 g / cm ³ or less.
A clad type positive electrode plate for a lead storage battery, wherein the ratio of the organic fiber to the positive electrode electrode material is 0.013% by volume or more and 0.5% by volume or less.

(6) In any one of the above (1) to (5), the ratio of the organic fiber to the positive electrode material may be 0.026% by volume or more.

(7) In any one of the above (1) to (6), the ratio of the organic fiber to the positive electrode material is 0.32% by volume or less, 0.25% by volume or less, or 0.23% by volume. It may be less than or equal to%.

(8) In any one of the above (1) to (7), the organic fiber may contain a fiber (first fiber) having a specific gravity of 1.2 or more.

(9) In the above (8), the specific gravity of the first fiber may be 1.25 or more or 1.26 or more.

(10) In the above (8) or (9), the specific gravity of the first fiber may be 1.7 or less, 1.6 or less, or 1.5 or less.

(11) In any one of the above (8) to (10), the ratio of the first fiber to the entire organic fiber contained in the positive electrode electrode material is 60% by volume or more, 75% by volume or more, or It may be 90% by volume or more.

(12) In the above (11), the ratio of the first fiber may be 100% by volume or less.

(13) In any one of the above (8) to (10), the positive electrode material may contain only the first fiber as the organic fiber.

(14) In any one of the above (1) to (13), the organic fiber may contain an oxygen element.

(15) In the above (14), the content of the oxygen element in the organic fiber is 10,000 μmol / g or more, 15,000 μmol / g or more, 17,000 μmol / g or more, 17400 μmol / g or more, 19000 μmol / g or more, 20000 μmol / g. The above, or 20800 μmol / g or more may be used.

(16) In the above (14) or (15), the content of the oxygen element in the organic fiber may be 50,000 μmol / g or less, 40,000 μmol / g or less, or 35,000 μmol / g or less.

(17) In any one of the above (1) to (16), the average fiber diameter of the organic fiber may be 1 μm or more, 5 μm or more, or 10 μm or more.

(18) In any one of the above (1) to (17), the average fiber diameter of the organic fiber may be 50 μm or less, 30 μm or less, or 20 μm or less.

(19) In any one of the above (1) to (18), the average fiber length of the organic fiber is 0.1 mm or more, 0.5 mm or more, 1 mm or more, 1.5 mm or more, or 2 mm or more. You may.

(20) In any one of the above (1) to (19), the average fiber length of the organic fiber may be 10 mm or less, or 6 mm or less.

(21) In any one of the above (1) to (20), the organic fiber may contain at least one selected from the group consisting of polyester fiber, acetalized polyvinyl alcohol fiber, polyurethane fiber, and cellulose fiber. good.

(22) In any one of the above (1) to (21), the density of the positive electrode material may be 3.7 g / cm ³ or less.

(23) In any one of the above (1) to (22), the density of the positive electrode material may be 3.3 g / cm ³ or more.

(24) Lead-acid battery
The lead-acid battery comprises at least one group of plates and an electrolytic solution.
The electrode plate group includes at least one clad type positive electrode plate according to any one of (1) to (23), at least one negative electrode plate, and a separator interposed between the clad type positive electrode plate and the negative electrode plate. A lead-acid battery.

(25) In the above (24), the negative electrode plate may contain a negative electrode material.

(26) In the above (25), the negative electrode material may contain an organic shrinkage proofing agent.

(27) In the above (26), the content of the organic shrinkage barrier in the negative electrode electrode material may be 0.01% by mass or more, or 0.05% by mass or more.

(28) In the above (26) or (27), the content of the organic shrinkage barrier in the negative electrode electrode material may be 1.0% by mass or less, or 0.5% by mass or less.

(29) In any one of the above (25) to (28), the negative electrode material may contain a carbonaceous material.

(30) In the above (29), the content of the carbonaceous material in the negative electrode material may be 0.05% by mass or more, or 0.10% by mass or more.

(31) In the above (29) or (30), the content of the carbonaceous material in the negative electrode electrode material may be 5% by mass or less, or 3% by mass or less.

(32) In any one of the above (25) to (31), the negative electrode material may contain barium sulfate.

(33) In the above (32), the content of the barium sulfate in the negative electrode electrode material may be 0.05% by mass or more, or 0.10% by mass or more.

(34) In the above (32) or (33), the content of the barium sulfate in the negative electrode electrode material may be 3% by mass or less, or 2% by mass or less.

(35) In any one of the above (25) to (34), even if the specific gravity of the electrolytic solution at 20 ° C. in the fully charged lead-acid battery is 1.20 or more, or 1.25 or more. good.

(36) In any one of the above (25) to (35), even if the specific gravity of the electrolytic solution at 20 ° C. in the fully charged lead-acid battery is 1.35 or less, or 1.32 or less. good.

[Example]
Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<< Lead-acid batteries E1 to E19, R1 to R2, and C1 to C6 >>
(1) Preparation of positive electrode plate A clad type positive electrode plate is manufactured by the following procedure.
First, each of the 15 cores having one end in the length direction integrated into the current collector provided with the selvage is housed in each of the 15 tubes. A resin upper collective punishment is formed by covering the current collector and one end of the tube in the length direction on the current collector side with resin so that the selvage is exposed. The material of the core metal and the current collector is a Pb—Sb alloy, and the length of each core metal is 295 mm. As the tube, a porous tube made of glass fiber having a length of 310 mm and an outer diameter of 9.5 mm is used.

A positive electrode slurry prepared by kneading lead powder (containing 80% by mass of lead oxide and 20% by mass of metallic lead), lead tan, the organic fibers shown in the table, water, and dilute sulfuric acid is added in the length direction of the tube. Fill through the opening at the end. The opening at the other end of the tube is then sealed with a lower punishment and dried. In this way, an unchemical clad type positive electrode plate is produced. The width of the produced positive electrode plate is 143 mm.

The mass ratio of lead powder and lead tan is 9: 1. The amount of organic fibers added is adjusted so that the number of organic fibers per unit volume (cm ³ ) of the positive electrode material or the ratio of organic fibers to the positive electrode material obtained by the above procedure is the value shown in the table. Will be done. The filling amount of the positive electrode slurry is adjusted so that the density of the positive electrode material obtained by the above-mentioned procedure becomes the value shown in the table. The average fiber diameter of the organic fiber obtained by the above-mentioned procedure is 14 μm, and the average fiber length is 2 mm.

(2) Preparation of negative electrode plate Lead powder (including 80% by mass of lead oxide and 20% by mass of metallic lead), 0.3% by mass of carbon black, 0.1% by mass of an organic shrinkage proofing agent (sodium lignin sulfonate), and Barium sulphate 1.5% by weight is mixed with water and dilute lead sulphate to prepare a negative paste. An unchemical negative electrode plate (thickness 4.5 mm) is produced by filling a cast lattice (thickness 4.4 mm) made of an Sb-based alloy as a negative electrode current collector with a negative electrode paste and drying it. The filling amount of the negative electrode paste is adjusted so that the mass of the negative electrode active material contained in the negative electrode material in one negative electrode plate after chemical conversion is 750 ± 6 g in terms of Pb element. The length of the negative electrode plate is the same as the length of the tube of the positive electrode plate, and the width of the negative electrode plate is the same as the width of the positive electrode plate.

(3) Preparation of lead-acid battery Four unchemical negative electrode plates and three unchemical clad positive electrode plates having core metal having the same shape are alternately stacked with a separator interposed therebetween. Then, a group of electrode plates as shown in FIG. 2B is formed. As the separator, a polypropylene microporous membrane having ribs on one surface is used. The separator is arranged so that the rib is located on the positive electrode plate side.

The electrode plate group is housed in a polypropylene electric tank, dilute sulfuric acid having a specific gravity of 1.280 at 20 ° C. is injected, and the lid is fixed to the opening of the electric tank by adhesion. Chemicalization is performed while the electric tank is held in a water tank at 30 ° C ± 2 ° C. In this way, lead-acid batteries E1 to E19, C1 to C6, and R1 to R2 having a rated voltage of 2 V and a rated capacity (5-hour rate) of 165 Ah are obtained. Lead-acid batteries are almost fully charged due to chemical formation.

(4) Evaluation (a) Incidence rate of voltage rise in high-temperature deep discharge cycle A high-temperature deep discharge cycle test is performed using a fully charged lead-acid battery. In the high-temperature deep discharge cycle test, the lead-acid battery is discharged at a current of 41.25 A for 3 hours and charged at a current of 29.7 A for 5.44 hours while being held in a water tank having a temperature of 75 ° C. ± 5 ° C. This discharge and charge cycle is regarded as one cycle, and 200 cycles of charging and discharging are repeated.

Calculate the ratio (%) of cycles in which the time required for the terminal voltage of the lead-acid battery to reach 2.4V during charging is less than 3.5 hours during charging and discharging of 200 cycles. This ratio corresponds to the rate of occurrence of voltage rise during charging in the high temperature deep discharge cycle test, and is an index for evaluating the voltage rise in the high temperature deep discharge cycle.

(B) Initial capacity For lead-acid batteries C1, E1 and E14 to E19, the initial capacity is measured by the following procedure.
First, the fully charged lead-acid battery is discharged to 70V with a current of 33A while being held in a water tank with a temperature of 30 ° C ± 2 ° C, and then 135% with respect to the amount of discharged electricity with a current of 33A. Charge until the amount of electricity reaches. Discharge to 1.70 V again with a current of 33 A, measure the discharge capacity at this time, and use this as the initial capacity. The initial capacity is evaluated by the ratio when the initial capacity of the lead storage battery C1 is 100%.
The results are shown in Tables 1 to 4 and FIGS. 3 to 9.

As shown in Table 1 and FIG. 3, in the positive electrode material of the clad type positive electrode plate, when the density is 3.75 g / cm ³ or less, the occurrence rate of the voltage increase in the high temperature deep discharge cycle increases (C1 to C1 to 3). Comparison of C4 and C5 to C6). On the other hand, since the positive electrode material contains organic fibers, the rate of voltage increase in the high temperature deep discharge cycle when the density is 3.75 g / cm ³ or less can be significantly reduced (C1 to C4 and E1 to). Comparison with E4). It is considered that this is because the presence of organic fibers in the positive electrode electrode material hinders the movement of ions and makes it difficult to generate a resistance component. When the density of the positive electrode material exceeds 3.75 g / cm ³ , there is no difference in the rate of voltage increase in the high temperature deep discharge cycle depending on the presence or absence of organic fibers (C5 to C6 and R1 to R2). Comparison with). In other words, there is no problem of voltage rise in the high temperature deep discharge cycle.

As shown in Table 2, FIG. 4 and FIG. 5, the effect of reducing the voltage rise in the high temperature deep discharge cycle is that the number of organic fibers per unit volume (cm ³ ) of the positive electrode material is 400 or more and / or the positive electrode. It can be obtained when the ratio of organic fibers to the electrode material is 0.013% by volume or more. From the viewpoint of further reducing the rate of voltage rise in the high temperature deep discharge cycle, the number of organic fibers per unit volume (cm ³ ) of the positive electrode material is 800 or more and / or the ratio of organic fibers to the positive electrode material. Is preferably 0.026% by volume or more.

As shown in Table 3 and FIG. 6, when the specific gravity of the organic fiber is 1.2 or more (preferably 1.25 or more or 1.26 or more), the occurrence rate of the voltage increase in the high temperature deep discharge cycle is determined. It can be further reduced.

As shown in Table 3 and FIG. 7, when the oxygen element content of the organic fiber is 15,000 μmol / g or more (preferably 17,000 μmol / g or more or 17,400 μmol / g or more), the voltage rise in the high temperature deep discharge cycle. The incidence can be further reduced.

It is considered that these effects are due to the increased dispersibility of the organic fibers in the positive electrode material, which further limits the movement of ions.

As shown in Table 4 and FIG. 8, the number of organic fibers per unit volume of the positive electrode material is more preferably 7500 or less or 7200 or less from the viewpoint of easily securing a higher initial capacity. From the same viewpoint, the ratio of the organic fiber to the positive electrode material is more preferably 0.25% by volume or less or 0.23% by volume or less (Tables 4 and 9).

The clad type positive electrode plate according to one aspect of the present invention can be suitably used for an industrial long-life lead-acid battery or a lead-acid battery for an electric vehicle (forklift, etc.). Further, the clad type positive electrode plate may be used for a lead storage battery for a vehicle such as an automobile or a motorcycle, for example. However, these applications are merely examples, and the applications of the clad type positive electrode plate and the lead storage battery provided with the clad type positive electrode plate are not limited to these.

1: Lead-acid battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 5a: Negative electrode strap 5b: Positive electrode strap 6a: Negative electrode column 6b: Positive electrode column 10: Electrode tank 11: Electrode plate group 12: Electrolyte

Claims

A clad type positive electrode plate for lead-acid batteries,
The positive electrode plate has a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and a plurality of core metal lengths arranged in a row. Equipped with a current collector that connects one end in the direction
The positive electrode material contains organic fibers and contains
The density of the positive electrode material is 3.75 g / cm 3 or less.
A clad type positive electrode plate for a lead storage battery, wherein the number of the organic fibers per unit volume (cm 3 ) of the positive electrode material is 400 or more and 15,000 or less.
The clad type positive electrode plate for a lead storage battery according to claim 1, wherein the number of the organic fibers per unit volume of the positive electrode material is 800 or more.
The clad type positive electrode plate for a lead storage battery according to claim 1 or 2, wherein the number of the organic fibers per unit volume of the positive electrode material is 10,000 or less.
The clad type positive electrode plate for a lead storage battery according to any one of claims 1 to 3, wherein the ratio of the organic fiber to the positive electrode material is 0.013% by volume or more and 0.5% by volume or less.
A clad type positive electrode plate for lead-acid batteries,
The positive electrode plate has a plurality of porous tubes, a core metal housed in the tube, a positive electrode material filled in the tube, and a plurality of core metal lengths arranged in a row. Equipped with a current collector that connects one end in the direction
The positive electrode material contains organic fibers and contains
The density of the positive electrode material is 3.75 g / cm 3 or less.
A clad type positive electrode plate for a lead storage battery, wherein the ratio of the organic fiber to the positive electrode electrode material is 0.013% by volume or more and 0.5% by volume or less.
The clad type positive electrode plate for a lead storage battery according to any one of claims 1 to 5, wherein the ratio of the organic fiber to the positive electrode material is 0.026% by volume or more.
The clad type positive electrode plate for a lead storage battery according to any one of claims 1 to 6, wherein the ratio of the organic fiber to the positive electrode material is 0.32% by volume or less.
The clad type positive electrode plate for a lead storage battery according to any one of claims 1 to 7, wherein the organic fiber contains a fiber having a specific gravity of 1.2 or more.
The organic fiber contains an oxygen element and contains
The clad type positive electrode plate for a lead storage battery according to any one of claims 1 to 8, wherein the content of the oxygen element in the organic fiber is 10,000 μmol / g or more.
The clad type positive electrode plate for a lead storage battery according to claim 9, wherein the content of the oxygen element in the organic fiber is 35,000 μmol / g or less.
The clad type for a lead storage battery according to any one of claims 1 to 10, wherein the organic fiber contains at least one selected from the group consisting of polyester fiber, acetalized polyvinyl alcohol fiber, polyurethane fiber, and cellulose fiber. Positive plate.
The clad type positive electrode plate for a lead storage battery according to any one of claims 1 to 11, wherein the density of the positive electrode material is 3.7 g / cm 3 or less.
The clad type positive electrode plate for a lead storage battery according to any one of claims 1 to 12, wherein the density of the positive electrode material is 3.3 g / cm 3 or more.
It ’s a lead-acid battery.
The lead-acid battery comprises at least one group of plates and an electrolytic solution.
The electrode plate group includes at least one clad type positive electrode plate according to any one of claims 1 to 13, at least one negative electrode plate, and a separator interposed between the clad type positive electrode plate and the negative electrode plate. A lead-acid battery.