JP2016162501A - Clad-type lead acid battery, clad-type positive electrode plate, and collector for clad-type positive electrode plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clad-type lead acid battery capable of maintaining the castability and durability of a core metal at the same time.SOLUTION: A core metal constituting a collector for a clad-type lead acid battery is prepared by casting a lead alloy containing 3.0 mass% or more and 7.0 mass% or less of antimony by a pressure casting method.SELECTED DRAWING: None

Description

  The present invention relates to a clad lead storage battery including a cored bar formed by casting a lead alloy, and a current collector and a positive electrode plate for the clad lead storage battery.

  Since a storage battery for an electric vehicle such as a forklift is required to have durability and impact resistance, a clad lead storage battery that has a long life and is resistant to vibration is generally used. In the clad lead storage battery, a clad positive plate is used as the positive plate. This clad type positive electrode plate has a plurality of cylindrical tubes (clad tubes) arranged, a metal core serving as a current collector is inserted into each clad tube, and lead serving as a positive electrode active material in a gap between each clad tube and the metal core An unformed electrode plate is prepared by filling powder, and this electrode plate is obtained by chemical conversion. In the conventional clad lead-acid battery, the cored bar constituting the clad positive plate is formed by gravity casting. Moreover, in order to improve the casting property of a core metal, antimony (Sb) is contained in the lead alloy which comprises a core metal (nonpatent literature 1).

Detchko Pavlov / Lead-Acid Batteries / Science and Technology / A hand book of lead-acid battery technology and its influence on the product / Elsevier Science Ltd

  However, if antimony is present in the core metal component that constitutes the current collector of the clad positive plate, the hydrogen overvoltage of the negative electrode tends to decrease and overcharge tends to occur, and the current collector (core metal) of the positive plate corrodes. Since it becomes easy, there exists a possibility of affecting the durability of lead acid battery (nonpatent literature 1).

  On the other hand, when thinning the clad positive plate, it is necessary to arrange as many thin tubes as possible in a limited space, so the cross-sectional dimensions of the cored bar (for example, cross-sectional area and cross-sectional diameter) must be as small as possible. There is. In order to produce a cored bar having such a small cross-sectional dimension, the content of antimony must be increased in order to maintain the castability of the cored bar. However, if the content of antimony is increased, the core metal is likely to corrode as described above, and the cross-sectional dimension of the core metal must be increased in consideration of the corrosion component in advance. Therefore, the conventional clad lead-acid battery has a limit in reducing the cross-sectional dimension of the cored bar.

  An object of the present invention is to provide a clad lead-acid battery capable of simultaneously maintaining the castability and durability of a metal core.

  Another object of the present invention is to provide a clad lead-acid battery capable of reducing the cross-sectional dimension of the cored bar.

  Still another object of the present invention is to provide a clad lead-acid battery having excellent discharge characteristics and a long battery life.

  A current collector for a clad lead storage battery to be improved by the present invention includes a metal core formed by casting a lead alloy. The lead alloy contains 3.0% by mass or more and 7.0% by mass or less of antimony (Sb) with respect to the total mass of the lead alloy. A pressure casting method is used for casting the lead alloy. The pressure casting method is a casting method in which a lead alloy melted in a melting pot is pushed into a mold at a predetermined injection rate using a hydraulic lead pump installed in the melting pot to produce a casting.

  Thus, the core metal obtained by casting the lead alloy containing a predetermined amount of antimony by the pressure casting method can maintain castability and durability (corrosion resistance, tensile strength). In the manufacture of a metal core using a conventional gravity casting method, it is difficult to manufacture the metal core unless the antimony content exceeds 5% by mass. On the other hand, in this invention, even if content of antimony is 5 mass% or less, since castability can be maintained, manufacture of a core metal is possible, maintaining durability. In particular, when the content of antimony satisfies the condition of 4.0% by mass or more and 5.0% by mass or less, the castability can be maintained and improved, so that the cored bar can be manufactured reliably. In addition, when the content of antimony in the lead alloy is less than 3.0% by mass, castability cannot be maintained, and when the content of antimony exceeds 7.0% by mass, the durability tends to decrease. .

  The lead alloy may contain 0.01% by mass or more and 0.45% by mass or less of arsenic (As) with respect to the total mass of the lead alloy. By casting the cored bar using a lead alloy containing such an arsenic content, the life can be extended. The content of arsenic is preferably 0.01% by mass to 0.40% by mass with respect to the total mass of the lead alloy. In such a content range, the battery life can be extended (for example, the life ratio can be increased) while improving the discharge characteristics (for example, while maintaining a high discharge capacity).

In addition, when the cored bar is cast under the above-described conditions, the cross-sectional dimensions of the cored bar (cross-sectional area, cross-sectional diameter dimension, etc.) can be reduced. Specifically, it is possible to average cross-sectional area when the core metal in which the void volume of the cladding tube constant is set to be 4.9 mm ² or more 7.1 mm ² or less. Here, the average cross-sectional area is defined as the average cross-sectional area when the cross-sectional area of the cross section cut in the direction orthogonal to the longitudinal direction of the core metal is averaged over the longitudinal direction of the core metal.

In the conventional clad lead-acid battery, as described above, from the viewpoint of castability and durability, when using a lead alloy having a relatively high antimony content, the cross-sectional dimension of the core metal has to be increased to some extent. . On the other hand, in the present invention, even when a lead alloy having a relatively low antimony content is used, castability and durability can be maintained at the same time. Can do. Further, when the cross-sectional dimension of the core metal is reduced, the space volume between the surface of the current collector (core metal) in the cladding tube and the inner wall of the cladding tube is increased. As a result, since the filling amount of the positive electrode active material can be increased on a clad tube basis, the discharge characteristics of the lead storage battery can be maintained or improved while maintaining the castability and durability. In particular, when the average cross-sectional area of the metal core is around 5.7 mm ² , all of castability, durability, and discharge characteristics are improved.

In addition, when the average cross-sectional area of the metal core is less than 4.9 mm ² , there is a possibility that a sufficient current collecting function cannot be obtained. Further, when the average cross-sectional area of the core bar exceeds 7.1 mm ² , the space for filling the positive electrode active material in the clad tube tends to be small. Therefore, the average cross-sectional area of the core is determined in the 7.1 mm ² or less in the numerical range 4.9 mm ² or more as described above. However, the relationship between the average cross-sectional area of the cored bar and the discharge characteristics is regulated by the space volume in the clad tube and is relatively determined by the filling amount of the positive electrode active material in the clad tube.

  The cross-sectional shape of the core metal is arbitrary, but if the cross-sectional contour shape is set to be circular, the pressure applied by pressure casting is applied evenly in the radial direction of the core metal, so casting is easy and the strength varies Can be obtained. Further, when the clad tube is cylindrical, if the cored bar is inserted into the center of the tube, the distance between the surface of the cored bar and the inner wall of the cylindrical clad tube can be made substantially uniform. In other words, since the positive electrode active material can be disposed almost uniformly between the current collector (core metal) and the inner wall of the clad tube, it can be expected that the lead-acid battery has a longer life and improved discharge characteristics.

The average cross-sectional area of the core metal (4.9 mm ² or more 7.1 mm ² or below), the average diameter of the core when the contour shape of the cross section defines the cross-sectional shape of the core metal so as to circle (Define section The average diameter of the cored bar is a numerical range of about 2.5 mm or more and 3.0 mm or less. Further, when the average cross-sectional area of the core metal is 5.7 mm ² , the average diameter is about 2.7 mm.

  The positive electrode plate for a clad lead storage battery of the present invention includes a current collector (core metal) obtained under the above conditions. Specifically, a tube and a current collector in a state in which a cylindrical glass fiber impregnated with phenol resin is sintered and a current collector (core metal) is inserted into the tube. The positive electrode active material is filled between the (core metal). By using a positive electrode plate for a clad lead-acid battery having such a configuration, a clad lead-acid battery having excellent discharge characteristics and a long life can be obtained.

  Moreover, in the positive electrode plate for a clad lead-acid battery of the present invention, the cross-sectional dimension of the current collector (core metal) can be reduced as described above. That is, since the filling space of the positive electrode active material in the clad tube can be increased, the filling amount of the positive electrode active material per one clad tube can be increased. Here, the established density means the density of the active material after chemical conversion. The low density of the active material indicates that the active material is porous. Therefore, in this invention, since the filling amount of the porous positive electrode active material can be increased, a clad lead storage battery having excellent discharge characteristics can be obtained.

The range of the established density is arbitrary, but is preferably set to a numerical range of 3.30 g / cm ³ or more and 3.75 g / cm ³ or less in order to achieve both discharge characteristics and battery life. Further, in order to improve the discharge specific and a longer battery life, range of Sundeka density is preferably determined to 3.40 g / cm ³ or more 3.65 g / cm ³ or less of numerical ranges. However, the relationship between the established density and the battery characteristics is regulated by the space volume in the cladding tube and is relatively determined by the filling amount of the positive electrode active material in the cladding tube.

(A) is a metallographic micrograph showing the structure of a current collector (core metal) of a clad positive plate cast using a conventional technique, and (B) is a diagram of the clad positive plate used in the examples of the present invention. It is a metal micrograph which shows the structure | tissue of a collector (core metal).

  Hereinafter, embodiments of the present invention will be described in detail. In this example, a vent type (liquid type) clad type lead acid battery is used as the clad type lead acid battery. In this clad lead-acid battery, a clad positive electrode plate and a paste negative electrode plate are accommodated in a battery case into which sulfuric acid electrolyte is injected. Furthermore, the lid portion of the battery case is provided with a refill water stopper.

  In the clad positive plate, a cored bar constituting the main part of the positive electrode current collector is inserted into a plurality of tubes (clad tubes) obtained by sintering cylindrical glass fibers impregnated with resin. It is configured by filling lead powder between gold.

  In this example, 15 clad tubes are used for one positive electrode plate. The cored bar is inserted so as to be positioned at the center of the clad tube in a state where these clad tubes are arranged in parallel. At both ends of the clad tube, joints (upper joint, lower joint) for holding the clad tube and the cored bar are attached. The upper joint is attached to one end of the clad tube (opening for inserting the cored bar and filling with lead powder), and the lower joint is the other end of the clad tube (the bottom of the clad tube). ) Is attached to the side. In this example, the dimensions of the cylindrical clad tube are defined as length: 294 mm, outer shape (diameter): 9.6 mm, and inner diameter (diameter): 9.0 mm.

  Each cored bar is integrally formed with a connecting portion that connects portions exposed to the outside of the cladding tube in a state of being inserted into the cladding tube. Furthermore, the edge part connected to a positive electrode terminal is provided in the edge part of a connection part. In other words, the positive electrode current collector is constituted by the cored bar, the connecting part, and the ear part.

  The metal core is made of a lead alloy containing lead (Pb) as a main component and a small amount of antimony (Sb). In this example, the Sb content and As content of the lead alloy were adjusted to the numerical values of the following examples and comparative examples.

  The core metal is obtained by casting by a pressure casting method. The core casting by the pressure casting method mainly includes a step of melting a lead alloy in a melting pot (internal temperature 480 ± 20 ° C.), a hydraulic cylinder pump (thrust: 50 kN, stroke 150 mm, pump speed 240 mm / s). ) In a pressurized mold (clamping force: 2000 to 4000 kN) and a step of cooling and releasing the mold. Note that the upper limit of the mold clamping force of the mold may exceed 4000 kN, but it is actually determined by the performance of the mold that can withstand the mold clamping force.

  In addition, while 15 clad tubes are used for one positive electrode plate, one positive electrode current collector is provided with 15 metal cores. The interval between the core bars is determined according to the interval in which the clad tubes are arranged. In addition, the length of the core bar per one is about 5 mm longer than the tube of each specification (considering the driving portion of the lower joint), and the cross-sectional dimension (average diameter) is 2.7 mm.

  Lead powder contains lead monoxide and metal lead as main components and becomes a positive electrode active material by chemical conversion in a state of being filled in a clad tube.

  On the other hand, the paste type negative electrode plate uses a negative electrode plate having a so-called bagging structure. In the production of this negative electrode plate, a paste kneaded with lead powder (lead monoxide), sulfuric acid, water, and additives (lignin, barium sulfate, cut fiber, etc.) is applied to a lead alloy lattice. Then, after an aging / drying process, a non-chemicalized paste-type negative electrode plate is obtained by using a PE (polyethylene) separator for preventing a short circuit.

  Using the positive electrode plate and the negative electrode plate thus obtained, a clad lead storage battery is produced. In this example, the above-described positive electrode plate and negative electrode plate are alternately stacked, and a strap and a pole column are welded to produce an electrode plate group. Thereafter, the electrode plate group is inserted into a PP (polypropylene) battery case, and the battery case and the PP lid are attached by heat welding to form an unformed battery. For the first charge (chemical conversion), as an example, after placing the above-mentioned non-chemical battery in a water tank filled with 40 ° C. water, and pouring sulfuric acid with a specific gravity of 1.240 into the battery through a liquid stopper, Initial charging is performed to a range of 300 to 350% of the amount of power applied at a current of 0.10 to 0.20 CA with respect to the battery capacity. Thereafter, adjustment is made so that the finished electrolyte specific gravity in the battery becomes 1.280.

  In this example, the density (established density) of the positive electrode active material after chemical conversion was adjusted as in Examples and Comparative Examples.

  Hereinafter, the relationship between the production conditions and various characteristics of the clad lead-acid battery was confirmed by comparing an example of the clad lead-acid battery and a comparative example.

First, the relationship between the casting type and the content of antimony (Sb) and various properties was confirmed. The production conditions of each example and comparative example are as follows.
Example 1
The casting type is pressure casting, the Sb content is 3.0 mass%, the As content is 0.005 mass% or less, the average diameter of the core metal is 2.7 mm, and the established density is 3.65 g / A clad lead-acid battery was produced under the condition of cm ³ .
(Example 2)
A clad lead storage battery was produced under the same conditions as in Example 1 except that the Sb content was 3.5% by mass.
(Example 3)
A clad lead-acid battery was produced under the same conditions as in Example 1 except that the Sb content was 4.0% by mass.
Example 4
A clad lead storage battery was produced under the same conditions as in Example 1 except that the Sb content was 4.5% by mass.
(Example 5)
A clad lead storage battery was produced under the same conditions as in Example 1 except that the Sb content was 5.0% by mass.
(Example 6)
A clad lead storage battery was produced under the same conditions as in Example 1 except that the Sb content was 6.0% by mass.
(Example 7)
A clad lead storage battery was produced under the same conditions as in Example 1 except that the Sb content was 7.0 mass%.
(Comparative Example 1)
The casting type is gravity casting, the Sb content is 2.0 mass%, the As content is 0.005 mass% or less, the average diameter of the core metal is 2.7 mm, and the established density is 3.65 g / cm. ^A clad lead storage battery was produced under the condition of ³ .
(Comparative Example 2)
A clad lead-acid battery was produced under the same conditions as in Comparative Example 1 except that the Sb content was 4.0% by mass.
(Comparative Example 3)
A clad lead storage battery was produced under the same conditions as in Comparative Example 1 except that the Sb content was 7.0% by mass.
(Comparative Example 4)
A clad lead storage battery was produced under the same conditions as in Comparative Example 1 except that the Sb content was 10.0% by mass.
(Comparative Example 5)
A clad lead-acid battery was produced under the same conditions as in Example 1 except that the Sb content was 2.0% by mass.
(Comparative Example 6)
A clad lead storage battery was produced under the same conditions as in Example 1 except that the Sb content was 7.5% by mass.

About the said Examples 1-7 and Comparative Examples 1-6, castability and durability (corrosion weight loss mentioned later and core metal elongation) were confirmed.
(Castability)
The fluidity of the molten metal during casting and the appearance of the core metal after casting (product retention, defects such as voids) were visually confirmed.

  Castability was evaluated based on the following evaluation criteria.

◎: Burrs and sink marks do not occur in the continuous manufacturing state ○: Burrs and sink marks occur rarely in the continuous manufacturing state △: Burrs and sink marks occur frequently in the continuous manufacturing state, but acceptable in manufacturing ×: Cannot be produced (corrosion loss)
About the clad lead acid battery, the life test-test method 1 prescribed | regulated to JISD5303-1 (Lead battery for electric vehicles-1st part: General requirements and test method) was implemented and evaluated. The discharge current of 0.25CA is 3h and the charging current of 0.18CA is 1h (3 cycles / day). The battery is disassembled every 300 cycles for each specification, and the positive electrode plate (core metal) Measure the amount of corrosion. Note that the test was terminated when the test was performed up to 1200 cycles. The difference in mass (corrosion amount of the core metal) between the positive electrode current collector before use and after use under this condition was regarded as corrosion weight loss, and the durability of the clad lead storage battery was confirmed from the viewpoint of this weight loss.

  Corrosion weight loss was evaluated based on the following evaluation criteria.

◎: Corrosion amount is very small ○: Corrosion amount is small △: Corrosion amount is slightly high ×: Corrosion amount is large (core metal elongation)
For the core bar whose corrosion weight has been confirmed, the core bar elongation (difference between the length of the core bar before use and the length of the core bar after use, hereinafter referred to as “core bar elongation”) is measured. The durability of the clad lead-acid battery was also confirmed from the viewpoint of gold elongation.

  The core metal elongation was evaluated based on the following evaluation criteria.

◎: Core metal elongation is extremely small ○: Metal core elongation is small △: Metal core elongation is slightly large ×: Metal core elongation is large (overall evaluation)
A comprehensive evaluation was performed from the evaluation results of castability, corrosion weight loss and core metal elongation. Comprehensive evaluation was evaluated based on the following evaluation criteria.

◎: Extremely good ○: Good ×: Defective If there is at least one “defect (x)” evaluation in each item, the overall evaluation is “defect (×)”. ) ”, But if there is at least one“ substantially good (△) ”, the overall evaluation is“ good (○) ”, and“ bad ”(×) or“ substantially good (△) ”in each item. In the absence of any of the evaluations, the overall evaluation was judged as “very good (（)”.

  Table 1 shows the results of confirming castability and durability (corrosion weight loss, core metal elongation) for Examples 1 to 7 and Comparative Examples 1 to 6.

From Table 1, first, Comparative Examples 1 to 4 [Casting type: Gravity casting (conventional casting method), Sb content: 2.0 to 10.0% by mass, average diameter of cored bar: 2.7 mm (constant), In the established density: 3.65 g / cm ³ (constant)], the overall evaluation was “bad” (x).

On the other hand, Examples 1 to 7 [casting type: pressure casting, Sb content: 3.0 to 7.0% by mass, average diameter of cored bar: 2.7 mm (constant), established density: 3 .65 g / cm ³ (constant)], the overall evaluation was “good (◯)” or higher. In particular, in Examples 3 to 5 [Sb content: 4.0 to 5.0% by mass], the overall evaluation was “very good (）)”. In Comparative Example 5, since the Sb content was low, the castability deteriorated. In Comparative Example 6, the Sb content was high, so the corrosion weight loss increased, and the overall evaluation was “bad” (x).

  From these results, it is possible to maintain both castability and durability by setting the casting type to pressure casting and adjusting the Sb content to 3.0 to 7.0% by mass. It has been found that the cross-sectional dimension of can be reduced.

  In addition, about the comparative example 2 (prior art) and Example 3 (this invention), the structure | tissue of a core metal was compared with the photograph which expanded and image | photographed the surface of the core metal using the metal microscope. The metal microscope used was a digital microscope VHX-1000 manufactured by KEYENCE, and the surface of the cored bar was magnified about 150 times and photographed. As a result, the conventional cored bar has a relatively coarse and non-uniform structure, whereas the cored bar used in the present invention has a relatively fine and almost uniform structure. Thus, the cored bar of the present invention shows a clear structural difference from the cored bar used in the prior art.

Next, various characteristics were confirmed when the cross-sectional dimension of the cored bar was also reduced under the condition that the inner diameter of the clad tube was small. The production conditions of each example and comparative example are as follows.
(Example 8)
The casting type is pressure casting, the Sb content is 4.0 mass%, the As content is 0.005 mass% or less, the average diameter of the core metal is 2.5 mm, and the established density is 3.65 g / A clad lead-acid battery was produced under the condition of cm ³ .
Example 9
A clad lead-acid battery was produced under the same conditions as in Example 8 except that the average diameter of the cored bar was set to 2.7 mm.
(Example 10)
A clad lead storage battery was produced under the same conditions as in Example 8 except that the average diameter of the cored bar was set to 3.0 mm.
(Comparative Example 7)
A clad lead-acid battery was produced under the same conditions as in Example 8 except that the average diameter of the cored bar was 2.0 mm.
(Comparative Example 8)
A clad lead-acid battery was produced under the same conditions as in Example 8 except that the average diameter of the cored bar was 3.5 mm.

For Examples 8 to 10 and Comparative Examples 7 and 8, the castability, discharge characteristics, and durability (corrosion weight loss, core metal elongation) were confirmed. Among these items, castability, corrosion weight loss, and core metal elongation were confirmed by the same method as described above. Moreover, comprehensive evaluation was performed similarly to the above.
(Discharge characteristics)
The discharge characteristics were confirmed based on the discharge capacity. The discharge capacity was carried out in accordance with a 5-hour rate capacity test specified in JIS D 5303-1 (lead battery for electric vehicles—Part 1: General requirements and test method). Specifically, the discharge start time is within 1 to 24 hours after full charge, the electrolyte temperature is 30 ° C. ± 2 ° C., the discharge current is a 5-hour rate current (0.20 CA with respect to the battery capacity), and the discharge end voltage Was carried out under the test conditions of 1.70 V / cell.

  The discharge capacity was evaluated based on the following evaluation criteria from the rated capacity ratio (%).

◎: Rated capacity ratio is 110% or more ○: Rated capacity ratio is 105% or more and less than 110% △: Rated capacity ratio is 95% or more and less than 105% ×: Rated capacity ratio is less than 95% Examples 8 to 10 and Comparative Examples Tables 1 and 8 show the results of confirming castability, discharge characteristics, and durability (corrosion weight loss, core metal elongation).

From Table 2, Examples 8 to 10 [Casting type: Pressure casting, Sb content: 4.0% by mass (constant), Average diameter of cored bar: 2.5-3.0 mm, Existing density: 3. 65 g / cm ³ (constant)], the overall evaluation was “good (◯)” or higher. In particular, in Example 9 [average diameter of core metal: 2.7 mm], the overall evaluation was “very good (◎)”. In Comparative Example 7, the average diameter of the cored bar is too small and current collecting performance is reduced. In Comparative Example 8, the average diameter of the cored bar is too large and the space in the cladding tube is narrowed (filling of the positive electrode active material). In all cases, the overall evaluation was “Bad (×)”.

  From these results, the discharge capacity (discharge characteristics) of the lead-acid battery can be maintained while maintaining the castability and durability even when the cross-sectional dimension of the cored bar becomes small due to the small inner diameter of the clad tube. understood.

Furthermore, when the inner diameter of the cladding tube was reduced and the cross-sectional dimension of the cored bar was also reduced, the relationship between the established density of the positive electrode active material and the battery characteristics was confirmed. Furthermore, the relationship between As addition amount and battery characteristics was also confirmed. The production conditions of each example and comparative example are as follows.
(Example 11)
The casting type is pressure casting, the Sb content is 4.0 mass%, the As content is 0.005 mass% or less, the average diameter of the core metal is 2.7 mm, and the established density is 3.30 g / A clad lead-acid battery was produced under the condition of cm ³ .
(Example 12)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the established density of the positive electrode active material was 3.40 g / cm ³ .
(Example 13)
A clad lead storage battery was fabricated under the same conditions as in Example 11 except that the established density of the positive electrode active material was 3.65 g / cm ³ .
(Example 14)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the established density of the positive electrode active material was 3.70 g / cm ³ .
(Example 15)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the established density of the positive electrode active material was 3.75 g / cm ³ .
(Comparative Example 9)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the established density of the positive electrode active material was 3.10 g / cm ³ .
(Comparative Example 10)
A clad lead storage battery was fabricated under the same conditions as in Example 11 except that the established density of the positive electrode active material was 4.15 g / cm ³ .
(Example 16)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the As content was 0.01% by mass.
(Example 17)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the As content was 0.20% by mass.
(Example 18)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the As content was 0.40% by mass.
(Example 19)
A clad lead storage battery was produced under the same conditions as in Example 11 except that the As content was 0.45% by mass.

For Examples 11 to 19 and Comparative Examples 9 and 10, the discharge capacity and battery life were confirmed.
(Discharge characteristics)
The discharge characteristics were confirmed based on the above-described discharge capacity (discharge capacity measured by the 5-hour rate capacity test specified in JIS D 5303-1 and evaluated from the rated capacity ratio (%)).
(Battery life)
The battery life was evaluated from the life ratio (%). The life ratio (%) was evaluated by carrying out the life test-test method 1 of JIS D 5303-1 (lead storage battery for electric vehicles-Part 1: General requirements and test methods). One cycle (3 cycles / day) with 3 hours at a discharge current of 0.25 CA and 5 h at a charge current of 0.18 CA, a 5-hour rate capacity test was performed every 100 cycles for each specification, and a rated capacity of 80 It is determined that the battery has reached the end of its life when it falls below%. The life ratio is based on Example 13.
(Comprehensive evaluation)
The overall evaluation of the battery characteristics was evaluated based on the following evaluation criteria.

A: Very good (when the discharge capacity is 95% or more and the life ratio is 90% or more)
○: Good (when the discharge capacity is 90% or more and less than 95% and the life ratio is 90% or more, or when the discharge capacity is 95% or more and the life ratio is 80% or more and less than 90%)
X: Defect (when discharge capacity is less than 90% or life ratio is less than 80%)
Table 3 shows the results of confirming the discharge capacity (%) and the life ratio (%) for Examples 11 to 19 and Comparative Examples 9 and 10.

From Table 3, Example 11-15 [Casting type: Pressure casting, Sb content: 4.0 mass% (constant), As content: 0.005 mass% or less, Average diameter of core metal: 2. 7 mm (constant) and established density: 3.30 to 3.75 g / cm ³ ], the overall evaluation was “good (◯)” or more. In particular, in Examples 12 to 14 [already formed density: 3.40 to 3.70 g / cm ³ ], the overall evaluation was “very good (◎)”. In Comparative Example 9, since the actual density was too small and the substantial filling amount of the positive electrode active material was reduced, the life ratio was lowered. In Comparative Example 10, the established density was too large and the positive electrode active material was porous. The discharge capacity decreased due to the lowering of the property, and the overall evaluation was “bad (×)”.

  From these results, even when the inner diameter of the clad tube is small, the cross-sectional dimension of the metal core can be reduced, so that the filling amount of the positive electrode active material can be secured, and the discharge capacity (discharge characteristics) and the life ratio ( Battery longevity) is maintained, or the discharge capacity and life ratio are both increased (both discharge characteristics and battery life are improved).

Examples 16 to 18 [Casting type: pressure casting, Sb content: 4.0 mass%, As content: 0.01 to 0.40 mass%, average diameter of core metal: 2.7 mm (constant ), An established density: 3.30 g / cm ³ (constant)], the overall evaluation was “very good (◎)”. In addition, in Example 19 (As content: 0.45 mass%), it was only “good (◯)”. In consideration of the fact that in Example 11 (As content: 0.005 mass% or less), it stopped at "Good (O)", a lead alloy containing 0.01 to 0.40 mass% As was used. It was found that by casting, the life ratio is increased (battery life is increased) while maintaining the discharge capacity (discharge characteristics).

  Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to these embodiments and experimental examples. For example, the number of clads, dimensions, etc. can be determined arbitrarily. That is, it is needless to say that the aspects described in the above embodiments and experimental examples can be changed based on the technical idea of the present invention unless otherwise specified.

  According to the present invention, by casting a lead alloy containing a predetermined amount of antimony on a current collector of a clad lead-acid battery, the castability and durability of the core metal can be maintained at the same time. Moreover, since the cross-sectional dimension of the cored bar can be reduced while simultaneously maintaining castability and durability, a clad lead acid battery having a thin clad lead acid battery positive electrode plate can be provided.

Claims (10)

A current collector for a clad lead storage battery comprising a cored bar formed by casting a lead alloy,
The lead alloy contains 3.0% by mass or more and 7.0% by mass or less of antimony with respect to the total mass of the lead alloy,
The current collector for a clad lead storage battery, wherein the core metal is formed by casting the lead alloy by a pressure casting method.   The collector for a clad lead-acid battery according to claim 1, wherein the content of the antimony is 4.0% by mass or more and 5.0% by mass or less with respect to the total mass of the lead alloy.   The current collector for a clad lead storage battery according to claim 1 or 2, wherein the lead alloy contains 0.01 mass% or more and 0.40 mass% or less of arsenic with respect to the total mass of the lead alloy. . The metal core has an average cross-sectional area of the cross-sectional area of the cross section cut in a direction perpendicular to the longitudinal direction were averaged in the longitudinal direction of the core metal of the metal core is 4.9 mm ² or more 7.1 mm ² or less The current collector for a clad lead-acid battery according to claim 1.   The current collector for a clad lead-acid battery according to claim 4, wherein the core has a circular outline in the cross section.   The current collector for a clad lead-acid battery according to claim 5, wherein an average diameter obtained by averaging the diameters of the cross-sections in the longitudinal direction of the cored bar is 2.5 mm or more and 3.0 mm or less. A positive electrode plate for a clad lead storage battery comprising the current collector according to any one of claims 1 to 6,
A tube constructed by sintering cylindrical glass fibers impregnated with phenolic resin;
A positive electrode plate for a clad lead-acid battery, further comprising a positive electrode active material filled between the tube and the core metal in a state where the core metal of the current collector is inserted into the tube. A positive electrode plate for a clad lead storage battery comprising the current collector according to any one of claims 1 to 6,
A tube constructed by sintering cylindrical glass fibers impregnated with phenolic resin;
In the state where the core of the current collector is inserted into the tube, further comprising a positive electrode active material filled between the tube and the core.
A positive electrode plate for a clad lead storage battery, wherein the positive electrode active material has a density of 3.30 g / cm ³ or more and 3.75 g / cm ³ or less. A clad lead-acid battery using a positive electrode plate comprising the current collector according to any one of claims 1 to 6,
A tube in which the positive electrode plate is further formed by sintering cylindrical glass fibers impregnated with phenol resin;
A clad lead-acid battery comprising a positive electrode active material filled between the tube and the core metal in a state where the core metal of the current collector is inserted into the tube. A clad lead-acid battery using a positive electrode plate comprising the current collector according to any one of claims 1 to 6,
A tube in which the positive electrode plate is further formed by sintering cylindrical glass fibers impregnated with phenol resin;
In a state in which the core of the current collector is inserted into the tube, a positive electrode active material filled between the tube and the core is provided,
A clad lead-acid battery in which the positive electrode active material has a density of 3.30 g / cm ³ or more and 3.75 g / cm ³ or less.