TWI733637B - Current collector for coated lead storage battery, positive plate for coated lead storage battery, and coated lead storage battery - Google Patents

Abstract

Provided are a current collector for a coated lead storage battery, a positive electrode plate for a coated lead storage battery, and a coated lead storage battery, which can simultaneously maintain the castability and durability of a core rod. The lead alloy is cast by a pressure casting method to produce a core rod, which constitutes a current collector for a coated lead storage battery, the lead alloy contains: 92% by mass or more and 97% by mass relative to the total mass of the alloy The following lead, and 3.0% by mass or more and 7.0% by mass or less antimony.

Description

Current collector for coated lead storage battery, positive plate for coated lead storage battery, and coated lead storage battery

The present invention relates to a current collector for a coated lead storage battery, a positive electrode plate for a coated lead storage battery, and a coated lead storage battery including a core rod formed by casting a lead alloy.

In batteries for electric vehicles such as stackers, durability and impact resistance are required, so a long-lived and highly vibration-resistant coated lead storage battery is generally used. In the coated lead storage battery, a coated positive plate is used for the positive plate. The coated positive plate is obtained by arranging a plurality of cylindrical tubes (coated tubes), and inserting the core rod as the current collector into each coated tube, and then it will be used as the positive electrode. The lead powder of the active material is filled in the gaps between each clad tube and the core rod to make an unformed polar plate, and then the polar plate is transformed into the clad positive plate. In the conventional coated lead storage battery, the core rod constituting the coated positive plate is formed by gravity casting. In addition, in order to improve the castability of the core rod, the lead alloy constituting the core rod contains antimony (Sb) (Non-Patent Document 1)

[Prior Technical Literature] (Non-patent literature) Non-Patent Document 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.

[The problem to be solved by the invention] However, if antimony is present in the core rod component of the current collector of the coated positive plate, the hydrogen overvoltage of the negative electrode tends to decrease and overcharge. The current collector (core rod) of the positive electrode plate It is prone to corrosion, so it may affect the durability of lead-acid batteries (Non-Patent Document 1).

On the other hand, in the case of thinning the clad positive plate, since it is necessary to arrange as many thin tubes as possible in a limited space, it is necessary to make the cross-sectional size of the core rod (such as the area of the cross-section or the diameter of the cross-section) ) Make it as small as possible. In order to produce a core rod with such a small cross-sectional dimension, the content of antimony must be increased to maintain the castability of the core rod. However, if the content of antimony is increased, the core rod becomes susceptible to corrosion as described above, and the cross-sectional size of the core rod has to be increased in consideration of the amount of corrosion in advance. Therefore, in the conventional coated lead storage battery, there is a limit to reduce the cross-sectional size of the core rod.

The object of the present invention is to provide a current collector for a coated lead storage battery, a positive electrode plate for a coated lead storage battery, and a coated lead storage battery that can maintain the castability and durability of the core rod at the same time.

Another object of the present invention is to provide a current collector for a coated lead storage battery, a positive electrode plate for a coated lead storage battery, and a coated lead storage battery that can reduce the cross-sectional size of the core rod.

A further object of the present invention is to provide a coated lead storage battery with excellent discharge characteristics and long battery life.

[Means to solve the problem] The current collector for a coated lead storage battery that is an improvement target of the present invention includes a core rod formed by casting a lead alloy. This lead alloy contains 92 mass% or more and 97 mass% or less of lead (Pb) and 3.0 mass% or more and 7.0 mass% or less of antimony (Sb) relative to the total mass of the alloy. Of course, the actual lead alloy may contain components other than antimony. Although the other components differ depending on the actual lead material used, they are arsenic (As), selenium (Se), bismuth (Bi), tin (Sn), etc. In addition, these other components can be regarded as unavoidable impurities contained in the raw materials even when the content is small.

For the casting of lead alloys, the pressure casting method is used. The pressure casting method is a manufacturing method in which a hydraulic lead pump installed in a melting pot is used to squeeze the lead alloy melted in the melting pot into a mold at a predetermined injection speed to produce a casting.

In this way, a lead alloy containing a predetermined amount of antimony is cast by a pressure casting method to obtain a mandrel, which can maintain castability and durability (corrosion resistance, tension resistance). In the manufacture of a core rod obtained by the conventional gravity casting method, unless the content of antimony is set to a condition of more than 5 mass%, it may be difficult to manufacture the core rod. On the other hand, in the invention of the present application, even if the antimony content is set to 5 mass% or less, the castability can be maintained, so the mandrel can be manufactured while 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, since the castability can be maintained and improved, the mandrel can be reliably manufactured. 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, durability tends to decrease.

The lead alloy may contain arsenic (As) in an amount of 0.01% by mass or more and 0.45% by mass or less with respect to the total mass of the lead alloy. By using a lead alloy containing arsenic in such a content to cast the core rod, the battery life can be prolonged. The content of arsenic is preferably 0.01% by mass or more and 0.40% by mass or less with respect to the total mass of the lead alloy. Within such a content range, not only the discharge characteristics are improved (for example, to maintain a high discharge capacity), but the battery life can be prolonged (for example, the life ratio is increased).

In addition, if the core rod is cast under the above-mentioned conditions, the cross-sectional dimensions of the core rod (the area of the cross-section, the diameter of the cross-section, etc.) can be reduced. Specifically, when the volume of the space of the sheathing tube is constant case, the average cross-sectional area can be provided to the mandrel ² and less than 7.1mm 4.9mm ^2. Here, the average cross-sectional area is defined as the average cross-sectional area when the cross-sectional area cut in the direction orthogonal to the longitudinal axis direction of the mandrel is averaged along the longitudinal axis of the entire mandrel.

In the conventional clad lead storage battery, as described above, from the viewpoint of castability and durability, in the case of using a lead alloy with a high content of antimony, the cross-sectional size of the core rod has to be enlarged to a certain level. One degree. In contrast, in the present invention, even if a lead alloy with a small antimony content is used, castability and durability can be maintained at the same time, so the cross-sectional size of the core rod can be made smaller than conventional ones. In addition, if the cross-sectional size of the core rod is reduced, the volume of the space between the surface of the current collector (core rod) in the coating tube and the inner wall of the coating tube becomes larger. As a result, since the filling amount of the positive electrode active material in each cell of the coated tube can be increased, it is possible to maintain or improve the discharge characteristics of the lead storage battery while maintaining the castability and durability. In particular, when the average cross-sectional area of the core rod is around 5.7 mm ² , any of castability, durability, and discharge characteristics is also improved.

Moreover, in the case where the average cross-sectional area of the core rod is less than 4.9 mm ² , it may not be possible to obtain sufficient power collection. In addition, when the average cross-sectional area of the core rod exceeds 7.1 mm ² , the filling space of the positive electrode active material in the coating tube tends to decrease. Thus, the average cross-sectional area of the mandrel a predetermined range of values, and in the ² or less than ² 4.9mm 7.1mm. However, the relationship between the average cross-sectional area of the core rod and the discharge characteristics is limited by the volume of the space in the cladding tube, and is relatively regulated in accordance with the filling amount of the positive electrode active material in the cladding tube.

The cross-sectional shape of the core rod is arbitrary, but if the contour shape of the predetermined cross-section becomes a circle, the pressure caused by pressure casting will be evenly applied in the diameter direction of the core rod, so the casting is easy and the strength is not uniform. There are very few mandrels in the situation. Furthermore, when the covering tube is cylindrical, if the core rod is inserted into the center of the tube, the distance between the surface of the core rod and the inner wall of the cylindrical covering tube can be made approximately the same. In other words, it is possible to arrange the positive electrode active material substantially uniformly between the current collector (core rod) and the inner wall of the cladding tube. Therefore, it is possible to expect a longer life of the lead acid battery and improvement of discharge characteristics.

Further, the average cross-sectional area of the mandrel (4.9mm 7.1mm ² or more and ² or less) is converted into a predetermined cross-sectional shape of the contour shape of the cross section of the mandrel becomes the average diameter mandrel so in case of a circular (defined : The average diameter obtained by averaging the diameter of the cross section in the direction along the longitudinal axis of the entire core rod), the average diameter of the core rod becomes a numerical range of approximately 2.5 mm or more and 3.0 mm or less. In addition, when the average cross-sectional area of the core rod is 5.7 mm ² , the average diameter becomes approximately 2.7 mm.

The positive electrode plate for the coated lead storage battery of the present invention includes a current collector (core rod) obtained under the above-mentioned conditions. Specifically, the positive electrode plate is configured as follows: a tube formed by sintering cylindrical glass fibers impregnated with phenol resin, and in a state where the current collector (core rod) is inserted into the tube, the positive electrode The active material is filled between the tube and the current collector (core rod). By using a positive electrode plate for a coated lead storage battery having such a configuration, a coated lead storage battery with excellent discharge characteristics and long life can be obtained.

In addition, in the positive electrode plate for a coated lead storage battery of the present invention, the cross-sectional size of the current collector (core rod) can be reduced as described above. That is, the filling space of the positive electrode active material in the coating tube can be enlarged, and therefore the filling amount of the positive electrode active material per coating tube can be increased. In the specification of this application, the "modified 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 the present invention, since the filling amount of the porous positive electrode active material can be increased, a coated lead storage battery having excellent discharge characteristics can be obtained.

Moreover, the range of the established density is an arbitrary range, but in order to balance discharge characteristics and battery life, it is preferable to specify a numerical range ^{of 3.30 g/cm 3} or more and 3.75 g/cm ^{3 or less.} In addition, in order to improve the discharge characteristics and prolong the battery life, it is preferable to set the range of the established density to a numerical range ^{of 3.40 g/cm 3} or more and 3.65 g/cm ^{3 or less.} However, the relationship between the established density and the battery characteristics is limited by the volume of the space in the coating tube, and is relatively regulated in accordance with the filling amount of the positive electrode active material in the coating tube.

Hereinafter, the embodiments of the present invention will be described in detail. In this example, a vent type (liquid type) coated lead storage battery is used as the coated lead storage battery. In this coated lead storage battery, the electrolyte of sulfuric acid is injected into the electrolytic cell, and the coated positive plate and the paste negative plate are housed in the electrolytic cell. Furthermore, a liquid plug for replenishing water is provided in the cover part of the electrolytic cell.

The coated positive electrode plate is constructed by sintering the cylindrical glass fiber impregnated with resin to form a plurality of tubes (coated tubes), and inserting the core rods into the respective tubes, and the core rods constitute the positive electrode assembly. The main part of the electric body is further filled with lead powder between the coating tube and the core rod.

In this example, as shown in an example of the manufacturing process in Fig. 2, 15 cladding tubes 1 are used for each positive electrode plate 15. The 15 core rods 6 are used to fit these cladding tubes 1 to a carrier plate (palette). In a state where the grooves 3 of 2 are arranged in parallel, they are inserted into the covering tube 1 and positioned at the center of the covering tube 1. The two ends of the cladding tube are equipped with connecting seats for holding the cladding tube 1 and the core rod 6 (the upper connecting seat 4 and the lower connecting seat 5). The upper connecting seat 4 is installed on the side of one end (the opening for inserting the core rod and filled with lead powder) of the covering tube 1, and is formed with a hole 19 through which the core rod 6 passes. The lower connecting seat 5 is installed in the coating tube 1 after filling the coating tube 1 with lead powder 7 from the other end of the coating tube 1 (the bottom of the coating tube 1) The end of the other side. In addition, in this example, the dimensions of the cylindrical coated tube 1 are specified as follows: a length of 294 mm, an outer diameter (diameter) of 9.6 mm, and an inner diameter (diameter) of 9.0 mm.

Each mandrel 6 is formed integrally with a connecting portion 8 that is connected to a portion of each mandrel 6 exposed to the outside of the covering pipe in a state where each mandrel 6 is inserted into the covering pipe. Furthermore, at the end of the connecting portion 8, there is provided an ear portion 9 connected to the positive terminal. In other words, the core rod 6, the connecting portion 8, and the ear portion 9 constitute a positive electrode current collector.

The core rod is composed of a lead alloy that contains lead (Pb) as a main component, a trace amount of antimony (Sb), and further contains a trace amount of components compared to the content of antimony. In this embodiment, 92 mass% or more and 97 mass% or less of lead (Pb) and 3.0 mass% or more and 7.0 mass% or less of antimony (Sb) are contained with respect to the total mass of the lead alloy.

From the viewpoint of further improving battery life, the core rod preferably contains arsenic (As). The content in the case of containing arsenic is preferably 0.01% by mass or more and 0.45% by mass or less, and more preferably 0.01% by mass or more and 0.40% by mass relative to the total amount of the lead alloy.

In addition, from the viewpoint that the castability and durability can be further improved, it is preferable to contain at least one selected from selenium, bismuth, and tin.

The content in the case of containing selenium is preferably 0.0001% by mass or more and 0.03% by mass or less with respect to the total amount of the lead alloy.

The content in the case of containing bismuth is preferably 0.0001% by mass or more and 0.03% by mass or less with respect to the total amount of the lead alloy.

The content in the case of containing tin is preferably 0.0001% by mass or more and 0.02% by mass or less with respect to the total amount of the lead alloy.

In addition, metals other than arsenic, selenium, bismuth, and tin may be included.

When the core rod contains metals other than antimony (Sb), the content of lead (Pb) may be 92% by mass or more and 96.5% by mass or less relative to the total mass of the lead alloy.

The so-called metals other than antimony (Sb) include, for example, metals such as calcium and silver and inevitable impurities in addition to arsenic, selenium, bismuth, and tin.

The mandrel is obtained by casting by the pressure casting method. The casting of the core rod carried out according to this pressure casting method is mainly composed of the following steps: the step of melting the lead alloy with the melting pot (internal temperature 480±20℃), the hydraulic cylinder pump (thrust 50kN, stroke 150mm, pump speed 240mm/s) to send to the pressurized mold (clamping force: 2000 ~ 4000kN) step, and cooling and demolding step. In addition, the upper limit of the clamping force of the mold may exceed 4000 kN, but it is actually specified according to the performance of the mold that can withstand the clamping force.

In addition, the strength of the core rod is 35 MPa or more, but from the viewpoint of castability and durability, it is preferably 37 MPa or more, and more preferably 40 MPa or more. In addition, the upper limit of the strength of the core rod is not particularly limited, but from the viewpoint of practicality, it is preferably 100 MPa or less, and more preferably 60 MPa or less. In addition, the above-mentioned strength core rod is preferably produced by a pressure casting method. However, technically, as long as the aforementioned strength can be obtained, it is not limited to the pressure casting method.

In addition, 15 coated tubes are used for each positive electrode plate, and one positive electrode current collector includes 15 core rods. The interval between the core rods is determined in accordance with the interval at which the coated tubes are arranged. In addition, compared to tubes with various lengths, the size of each core rod is about 5mm longer (taking into account the amount of penetration of the lower connecting seat), and the cross-sectional size (average diameter) is 2.7mm.

The lead powder is mainly composed of lead monoxide and metallic lead, and becomes a positive electrode active material by chemically forming in a state of being filled in a coated tube.

On the other hand, the paste type negative electrode plate uses a so-called bagged negative electrode plate. In the manufacture of this negative electrode plate, a paste obtained by kneading lead powder (lead monoxide), sulfuric acid, water, and additives (lignin, barium sulfate, cut fibers, etc.) is applied to a grid of lead alloys. After that, through the maturation and drying steps, a separator made of PE (polyethylene) for short-circuit prevention is used for bagging to obtain an unformed paste-type negative electrode plate.

Using the positive and negative plates obtained in this way, a coated lead storage battery was produced. In this example, the above-mentioned positive electrode plate and negative electrode plate are alternately stacked, and electrode straps and electrode columns are welded to produce an electrode plate group. After that, these electrode plate groups were inserted into an electrolytic cell made of PP (polypropylene), and the electrolytic cell and the cover made of PP were attached by thermal welding to make an unformed battery. Regarding the initial charge (chemical conversion), for example, put the above-mentioned unformed battery in a water tank containing water at 40°C, and pour the liquid into the battery with sulfuric acid with a specific gravity of 1.240 through a liquid plug. At the current of 0.10～0.20CA of battery capacity, the initial charge is carried out until the charged capacity is in the range of 300%～350% of the theoretical capacity. After that, adjustment is made so that the specific gravity of the completed electrolyte in the battery becomes 1.280.

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

[Example] Hereinafter, by comparing the examples and comparative examples of the coated lead storage battery, the relationship between the production conditions and various characteristics in the coated lead storage battery will be confirmed.

First, confirm the relationship between the casting form and the content of antimony (Sb) and various characteristics. The production conditions of each Example and Comparative Example are as follows.

＜Mandrel Making＞ Pressure casting of the embodiment: After melting the lead alloy in a melting pot (internal temperature 480±20℃), it is sent out into the pressurized mold (clamping force: 3000N) by a hydraulic cylinder pump (thrust: 50kN, stroke 150mm, pump speed 240mm/s) . After that, it was cooled at room temperature for 20 seconds, and then demolded from the mold to obtain a core rod.

Gravity casting of the comparative example: After melting the lead alloy in a melting pot (internal temperature 480±20°C), pick up 760g of molten alloy (hereinafter referred to as molten broth) with a casting ladle, and pour it into a mold adjusted to 180°C. After that, it was cooled at room temperature for 60 seconds, and then demolded from the mold to obtain a core rod. In either case, the effective height of the current collector is 285 mm.

＜Measuring the strength of mandrel＞ Prepare the positive electrode plate core rod to be cut into 70mm with pliers. It depends on the design of the mandrel, but the typical test piece is a cylindrical (rod) shape of 2.7mmφ×70mm. The testing machine (tensile testing machine) is a desktop material testing machine STA-1225 manufactured by Orientec, and the measurement is performed at 25±2°C under the condition of 100 mm/min.

＜Production of negative plate＞ Based on the total mass of the lead powder, 0.2% by mass of sodium lignosulfonate and 0.3% by mass of barium sulfate were added to the lead powder, followed by dry mixing. Then, while adding dilute sulfuric acid (specific gravity 1.26 (calculated at 20°C)) and water, they were kneaded to prepare a negative electrode active material paste. The negative electrode active material paste was filled in a cast current collector (Pb-Sb-As-Se) having a thickness of 4 mm to produce a negative electrode plate. Following the usual method, the negative electrode plate was placed in an atmosphere with a temperature of 40°C and a humidity of 98% for 16 hours to mature, and then dried in an atmosphere with a temperature of 60°C for 24 hours to obtain an unformed negative plate.

＜Production of positive plate＞ As shown in the manufacturing steps of the coated positive electrode plate shown in Figure 2, on the aluminum alloy carrier plate 2 having a plurality of grooves 3 formed in a semicircular recessed shape, the coated tubes 1 are neatly arranged (the first 2 Figure (a)). The covering tube 1 is formed into a cylindrical body by woven glass fibers into a cylindrical shape, impregnated with a water-soluble thermosetting resin (for example, phenol resin), and sintered. After inserting the upper connecting seat 4 with the hole 19 into one end of the neatly arranged covering tube 1, insert a core rod that functions as a current collector from the hole 19 of the upper connecting seat 4 6 (Figure 2(b)). In addition, as the material of the core rod 6, a lead-antimony alloy (component ratio shown in Table 1 to Table 6) that can exert an age hardening effect in a short time is used.

Then, in the state opposite to the above (the state where the core rod 6 or the upper connecting seat 4 is underneath), the lead powder 7 (lead powder with lead monoxide as the main component and lead powder) that functions as the positive electrode active material is made from above. The mixture of Dan powder) is dropped, and the lead powder 7 is filled in the gap between the coating tube 1 and the core rod 6. The lead powder 7 filled in the gap between the coating tube 1 and the core rod 6 is then chemically converted into a positive electrode active material. Finally, in the other opening of the coated tube 1, insert the connecting seat 5 at the lower part without a hole in the center, so that the lead powder 7 does not fall off, and the coated positive plate is completed (Figure 2(c)). The capacity equivalent to each positive electrode plate is about 58 Ah.

＜Assembly of battery＞ The separator made of polyethylene is processed into a bag shape, and the unformed negative electrode plate is inserted into the separator. Then, the eight unformed negative plates and seven unformed positive plates are stacked in a welding frame, so that the unformed positive plates and the unformed negative plates inserted into the bag-shaped separator are alternately laminated. Next, the pole post of the terminal is set in the mold, the welding frame containing the previous electrode plate group is butted from the bottom, and the ears of the electrode plates of the same polarity are welded by automatic welding to produce the electrode plate group. Insert the aforementioned plate group into the electrolytic cell, and assemble a 2V single cell battery. For this battery, in the early stage shown in Japanese Patent Publication No. 4888209, it was formed by injecting (compared to the second stage) dilute sulfuric acid into the electrolyte, and on the way, it was formed with a thicker sulfuric acid than the first stage. The way to get the battery. The total time of charging is 48 hours, which is a mode including stop/discharge on the way, and the maximum current is 120A. In this way, a battery that is 2V-400Ah under the condition of 30°C-5 hour rate (hour rate) is produced.

[Measurement of the established density of the positive electrode active material] The density of the established active material of the positive electrode was measured in the following manner. First, after washing the formed positive electrode plate with water for one hour, it was dried at 60° C. for 20 hours in a nitrogen atmosphere. Then, the negative electrode material was collected from the surface and the inside of the dried negative electrode plate. Using a porosimeter (AutoPore IV9500) manufactured by Shimadzu Corporation as an analysis device, the density of the negative electrode material was measured from the relationship between the pore volume at a measurement pressure of 2.00 psi and the dry mass by the mercury intrusion method. The details of the measurement conditions are as follows.

{Measurement conditions of the established density (apparent density) of the positive electrode active material} Analysis device: AutoPoreIV9500 (manufactured by Shimadzu Corporation) Mercury intrusion pressure: 0～354kPa (low pressure), atmospheric pressure～414MPa (high pressure) Pressure retention time under each measured pressure: 900s (low pressure), 1200s (high pressure) Contact angle between sample and mercury: 130 degrees Surface tension of mercury: 480～490mN/m The density of mercury: 13.5335g/mL

(Example 1-1) Pressure casting was used as the casting method. As shown in Table 1, the Sb content was set to 3.0% by mass, the As content was set to 0.005% by mass or less, and the other components (Se, Bi, Sn) were set to 0.0005% by mass or less, the average diameter of the core rod is set to 2.7 mm, the established density is set to 3.65 g/cm ³ , and the covered lead storage battery is produced under the above-mentioned conditions.

(Example 1-2) Except that the Sb content was 3.5% by mass, the covered lead storage battery was produced under the same conditions as in Example 1-1.

(Example 1-3) Except for setting the Sb content to 4.0% by mass, the covered lead storage battery was produced under the same conditions as in Example 1-1.

(Example 1-4) Except for setting the Sb content to 4.5% by mass, the covered lead storage battery was produced under the same conditions as in Example 1-1.

(Example 1-5) Except that the Sb content was 5.0% by mass, the covered lead storage battery was produced under the same conditions as in Example 1-1.

(Example 1-6) Except for setting the Sb content to 6.0% by mass, the covered lead storage battery was produced under the same conditions as in Example 1-1.

(Example 1-7) Except that the Sb content was set to 7.0% by mass, the covered lead storage battery was produced under the same conditions as in Example 1-1.

(Comparative Example 1-1) Gravity casting is used as the casting method. As shown in Table 1, the Sb content is set to 2.0% by mass, the As content is set to 0.005% by mass or less, and the other components (Se, Bi, Sn) are set to 0.0005 The mass% or less, the average diameter of the core rod was set to 2.7 mm, the established density was set to 3.65 g/cm ³ , and the covered lead storage battery was produced under the above-mentioned conditions.

(Comparative example 1-2) Except for setting the Sb content to 4.0% by mass, the covered lead storage battery was produced under the same conditions as in Comparative Example 1-1.

(Comparative example 1-3) Except that the Sb content was set to 7.0% by mass, the coated lead storage battery was produced under the same conditions as in Comparative Example 1-1.

(Comparative example 1-4) Except that the Sb content was 10.0% by mass, the covered lead storage battery was produced under the same conditions as in Comparative Example 1-1.

(Comparative example 1-5) Except for setting the Sb content to 2.0% by mass, the covered lead storage battery was produced under the same conditions as in Example 1-1.

(Comparative example 1-6) The covered lead storage battery was produced under the same conditions as in Example 1-1 except that the Sb content was set to 7.5% by mass.

Regarding the above-mentioned Examples 1-1 to 1-7 and Comparative Examples 1-1 to 1-6 shown in Table 1, the castability and durability (corrosion loss and mandrel elongation described later) were confirmed.

(Castability) Visually confirm the fluidity of the molten metal during casting or the appearance of the core rod after casting (defects such as product retention and voids).

Castability is evaluated based on the following evaluation criteria. A: In the continuous production state, no burrs and casting defects occur. B: In the continuous production state, the occurrence of burrs and casting defects is very rare. C: In the continuous production state, although burrs and casting defects occur at a certain frequency, they are tolerable in terms of production. D: Unable to make.

(Corrosion loss) For the coated lead storage battery, the life test-test method 1 stipulated in JIS D 5303-1 (lead storage battery for electric vehicles-Part 1: General requirements and test methods) is implemented for evaluation. With a discharge current of 0.25CA and a charging current of 3 hours and 0.18CA, 5 hours are regarded as 1 cycle (3 cycles per day). For various specifications, the battery is disassembled every 300 cycles to measure the positive plate (core Rod) corrosion amount. In addition, the test was completed until 1,200 cycles were performed. Under these conditions, the difference in quality (corrosion amount of the core rod) of the positive electrode current collector before and after use was taken as the amount of corrosion loss, and the durability of the coated lead storage battery was confirmed from the viewpoint of the amount of corrosion loss.

The amount of corrosion loss is evaluated based on the following evaluation criteria. A: Very little corrosion B: Less corrosion C: Slightly more corrosion D: A lot of corrosion

(Mandrel extension) For the mandrel for which the above-mentioned corrosion loss has been confirmed, the elongation of the mandrel (the difference between the length of the mandrel before use and the length of the mandrel after use, hereinafter referred to as "mandrel elongation") is also measured based on this From the point of view of mandrel elongation, the durability of the coated lead-acid battery was confirmed.

The elongation of the mandrel was evaluated based on the following evaluation criteria. A: The extension of the core rod is extremely small B: Mandrel extension is small C: The extension of the mandrel is slightly larger D: The mandrel has a large extension

(Comprehensive Evaluation) Comprehensive evaluation is carried out from the evaluation results of castability, corrosion loss, and mandrel elongation. Comprehensive evaluation is based on the following evaluation criteria. A: Very good B: good C: Generally good D: Bad

In addition, even if there is an evaluation of "bad (D)" in each item, the comprehensive evaluation is set to "bad (D)", and there is no "bad (D)" in each item, but even if there is a "slightly good (C) In the case of the evaluation of ")", the comprehensive evaluation is set to "Roughly Good (C)", and in the case of the evaluation of all "B" in each item, it is set to "Good (B)", and each item has "A" and In the case of "B", if there is no "bad (D)" nor "approximately good (C)" evaluation, the comprehensive evaluation is judged to be "extremely good (A)".

Regarding Examples 1-1 to 1-7 and Comparative Examples 1-1 to 1-6, the results of confirming castability and durability (corrosion loss, mandrel elongation) are shown in Table 1 as a comprehensive evaluation.

[Table 1]

As can be seen from Table 1, first, in Comparative Examples 1-1 to 1-4, the comprehensive evaluation of any one of them is "bad (D)"; the casting form of Comparative Examples 1-1 to 1-4 is gravity casting (the conventional The casting method), the Sb content is 2.0-10.0% by mass, the average diameter of the core rod is 2.7mm (fixed), and the established density is 3.65g/cm ³ (fixed).

In contrast, in Examples 1-1 to 1-7, the overall evaluation of any one of them was a result of "approximately good (C)" or higher; the casting form of Examples 1-1 to 1-7 was pressure casting The Sb content is 3.0-7.0% by mass, the average diameter of the core rod is 2.7mm (fixed), and the established density is 3.65g/cm ³ (fixed). In particular, in Examples 1-3 to 1-5 (Sb content: 4.0 to 5.0% by mass), the overall evaluation was "extremely good (A)". In addition, in Comparative Example 1-5, because the Sb content was small, the castability deteriorated. In Comparative Example 1-6, the corrosion loss was increased due to the large Sb content. The comprehensive evaluation of any of the above was "bad (D) ".

From these results, it can be judged that by setting the casting form to pressure casting and adjusting the Sb content to 3.0% by mass to 7.0% by mass, both castability and durability can be maintained, and the cross-sectional dimensions of the mandrel can also be changed. Small.

In addition, for Comparative Example 1-2 (the conventional technology) and Example 1-3 (the invention of this application), a metal microscope was used to magnify the surface of the mandrel to obtain a photograph, and the structure of the mandrel was compared with the photograph. In the metal microscope, a digital microscope VHX-1000 manufactured by KEYENCE was used, and the surface of the core rod was magnified approximately 150 times to take a picture. As a result, in the conventional core rod, the structure is relatively thick and uneven. In contrast, in the core rod used in the present invention, the structure is relatively thin and roughly uniform. In this way, the core rod of the present invention has a clear difference in structure from the core rod using the conventional technology.

Then, under the condition that the inner diameter of the cladding tube is small, various characteristics of the case where the cross-sectional size of the core rod (the average diameter of the core rod) is changed are confirmed. The production conditions of each Example and Comparative Example are as follows.

(Example 2-1) Pressure casting was used as the casting form. As shown in Table 2, the Sb content was set to 4.0% by mass, the As content was set to 0.005% by mass or less, and the other components (Se, Bi, Sn) were set to 0.0005% by mass or less, the average diameter of the core rod is set to 2.5 mm, the established density is set to 3.65 g/cm ³ , and the covered lead storage battery is produced under the above-mentioned conditions.

(Example 2-2 (same as Example 1-3)) Except that the average diameter of the core rod was set to 2.7 mm, the covered lead storage battery was produced under the same conditions as in Example 2-1.

(Example 2-3) Except that the average diameter of the core rod was 3.0 mm, the covered lead storage battery was produced under the same conditions as in Example 2-1.

(Comparative Example 2-1) Except that the average diameter of the core rod was set to 2.0 mm, the covered lead storage battery was produced under the same conditions as in Example 2-1.

(Comparative Example 2-2) Except that the average diameter of the core rod was 3.5 mm, the covered lead storage battery was produced under the same conditions as in Example 2-1.

Regarding the foregoing Examples 2-1 to 2-3 and Comparative Examples 2-1 and 2-2, the castability, discharge characteristics, and durability (corrosion loss, mandrel elongation) were confirmed. Among these items, the castability, the amount of corrosion loss, and the elongation of the mandrel were confirmed by the same method as above. In addition, the comprehensive evaluation is also carried out in the same way as above.

(Discharge characteristics) The discharge characteristics are confirmed based on the discharge capacity. The discharge capacity is evaluated in accordance with the 5-hour rate capacity test specified in JIS D 5303- (Lead Storage Battery for Electric Vehicles-Part 1: General Requirements and Test Methods). 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 (relative to the battery capacity is 0.20CA), and the discharge end voltage is within 1. The test conditions of 70V/unit are implemented.

The discharge capacity can be estimated from the rated capacity ratio (%) based on the following evaluation criteria. A: The rated capacity is more than 110% B: The rated capacity is more than 105% and less than 110% C: The rated capacity is more than 95% and less than 105% D: The rated capacity ratio is less than 95%

For Examples 2-1 to 2-3 and Comparative Examples 2-1 and 2-2, the results of confirming the castability, discharge characteristics, and durability (the amount of corrosion loss, the elongation of the mandrel) are shown in Table 2.

[Table 2]

According to Table 2, the comprehensive evaluation result of any one of Examples 2-1 to 2-3 is "approximately good (C)" or higher; the casting form of Examples 2-1 to 2-3 is pressure casting, and the Sb content It is 4.0% by mass (fixed), the average diameter of the core rod is 2.5 to 3.0 mm, and the established density is set to 3.65 g/cm ³ (fixed). In particular, in Example 2-2 (average core rod diameter of 2.7 mm), the overall evaluation was “good (B)”. In addition, in Comparative Example 2-1, the average diameter of the core rod was too small, and the current collection performance was reduced. In Comparative Example 2-2, the average diameter of the core rod was too large, and the space in the coating tube became narrow (due to the The filling amount becomes less), and the comprehensive evaluation of either one is "bad (D)". If judged by the aforementioned evaluation of the discharge capacity ratio, since Examples 2-1 to 2-3 become evaluation B and evaluation C, there is no problem in practicality.

From these results, it can be judged that even when the cross-sectional size of the core rod is reduced due to the small inner diameter of the cladding tube, not only the castability and durability are maintained, but the discharge capacity (discharge characteristics) of the lead-acid battery is also maintained.

Furthermore, when the inner diameter of the coated tube was reduced and the cross-sectional size of the core rod 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 the amount of As added and battery characteristics was also confirmed. The production conditions of each Example and Comparative Example are as follows.

(Example 3-1) Pressure casting was used as the casting form, as shown in Table 3, the Sb content was set to 4.0% by mass, the As content was changed, and the other components (Se, Bi, Sn) were set to 0.0005 mass% or less, The average diameter of the core rod was fixed at 2.7 mm, the established density was set at 3.10 g/cm ³ , and the covered lead storage battery was produced under the above-mentioned conditions.

(Example 3-2) Except that the established density of the positive electrode active material was set to 3.30 g/cm ³ , the covered lead storage battery was produced under the same conditions as in Example 3-1.

(Example 3-3) Except that the established density of the positive electrode active material was set to 3.40 g/cm ³ , the same conditions as in Example 3-1 were used to produce a coated lead storage battery.

(Example 3-4 (same as Example 1-3)) The coated lead was produced under the same conditions as Example 3-1 except that the established density of the positive electrode active material was set to 3.65 g/cm ³ Battery.

(Example 3-5) Except that the established density of the positive electrode active material was set to 3.70 g/cm ³ , the covered lead storage battery was produced under the same conditions as in Example 3-1.

(Example 3-6) Except that the established density of the positive electrode active material was set to 3.75 g/cm ³ , the covered lead storage battery was produced under the same conditions as in Example 3-1.

(Example 3-7) Except that the established density of the positive electrode active material was set to 4.15 g/cm ³ , the covered lead storage battery was produced under the same conditions as in Example 3-1.

(Example 3-8) Except for setting the As content to 0.01% by mass, the coated lead storage battery was produced under the same conditions as in Example 3-1.

(Example 3-9) Except that the As content was 0.20% by mass, the coated lead storage battery was produced under the same conditions as in Example 3-1.

(Example 3-10) Except for setting the As content to 0.40% by mass, the coated lead storage battery was produced under the same conditions as in Example 3-1.

(Example 3-11) Except for setting the As content to 0.45% by mass, the coated lead storage battery was produced under the same conditions as in Example 3-1.

The discharge capacity and battery life were confirmed for the above-mentioned Examples 3-1 to 3-11.

(Discharge characteristics) The discharge characteristics were confirmed based on the above-mentioned discharge capacity, which was 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 is evaluated from the life ratio (%). The life ratio (%) is evaluated by implementing the life test-test method 1 of JIS D 5303-1 (lead battery for electric vehicles-Part 1: General requirements and test methods). Take a discharge current of 0.25CA for 3 hours and a charge current of 0.18CA for 5 hours as 1 cycle (3 cycles per day), and perform a 5-hour rate capacity test for every 100 cycles of each specification. When it is less than 80% of the rated capacity , It is determined that the battery has reached the end of its life. In addition, the life ratio is based on Example 3-4.

(Evaluation of battery characteristics) The evaluation of battery characteristics, which is evaluated only from the viewpoint of the ratio of discharge capacity to life, can be evaluated based on the following evaluation criteria. A: Very good (when the discharge capacity is more than 95% and the life ratio is more than 90%) B: Good (when the discharge capacity is 90% or more and less than 95% and the life ratio is 90% or more, or if the discharge capacity is 95% or more and the life ratio is 80% or more and less than 90%) C: Roughly good (when the discharge capacity is more than 80% and less than 90%, or if the life ratio is more than 70% and less than 80%)

[table 3]

In accordance with the above-mentioned evaluation criteria of battery characteristics, in the comprehensive evaluation of battery characteristics from the viewpoint of the ratio of discharge capacity to life, first, the evaluation of any one of Examples 3-3 to 3-5 and Examples 3-8 to 3-10 It is "extremely good (A)" or higher; the casting form of Examples 3-3 to 3-5 is pressure casting, the Sb content is 4.0 mass% (fixed), the As content is 0.005 mass% or less, and the average diameter of the core rod It is 2.7mm (fixed), the established density is 3.30～3.75g/cm ³ , and the casting form of Examples 3-8～3-10 is pressure casting, the Sb content is 4.0% by mass (fixed), and the As content is 0.01 to 0.45 mass%, the average diameter of the core rod is 2.7 mm (fixed), and the established density is fixed to 3.30 g/cm ³ . In addition, in Example 3-1, because the modified density was too low and the substantial filling amount of the positive electrode active material was reduced, the life ratio was reduced, while in Examples 3-7, the porosity of the positive electrode active material was reduced because the modified density was too high. Low, so the discharge capacity is reduced, and the evaluation of either one is "approximately good (C)".

From these results, it can be judged that even when the inner diameter of the cladding tube is small, the cross-sectional size of the core rod can be made small, so the filling amount of the positive electrode active material can be ensured, and the discharge capacity (discharge characteristics) and the life ratio (battery life) can be maintained. ), or any one of the discharge capacity and the life ratio becomes higher (both the discharge characteristics and the battery life are improved).

In addition, the comprehensive evaluation of any one of Examples 3-8 to 3-10 is "extremely good (A)"; the casting form of Examples 3-8 to 3-10 is pressure casting, and the Sb content is 4.0 Mass%, the As content is 0.01 to 0.40% by mass, the average diameter of the core rod is 2.7 mm (fixed), and the established density is 3.30/cm ³ (fixed). In addition, Example 3-11 (As content is 0.45% by mass) ended in "good (B)". Considering the case of Example 3-2 (As content of 0.005 mass% or less) and stopping at "good (B)", it can be judged that the use of a lead alloy containing 0.01 to 0.40 mass% of As for casting can not only maintain the discharge capacity (discharge) Features), the life ratio also becomes higher (battery life becomes longer).

Furthermore, various characteristics of the case where the lead alloy of the cast mandrel contains selenium (Se), bismuth (Bi), and tin (Sn) other than As were confirmed. The preparation conditions of each example are as follows.

(Example 4-1) Pressure casting was used as the casting method. As shown in Table 4, the Sb content was 3.5% by mass, the As content was 0.01% by mass, and the contents of Se, Bi, and Sn were all set. It is 0.0005% by mass or less, the average diameter of the core rod is fixed to 2.7 mm, the established density is set to 3.65 g/cm ³ , and the covered lead storage battery is produced under the above-mentioned conditions.

(Examples 4-2 to 4-4) Except that the As content was set to 0.1% by mass, 0.3% by mass, and 0.45% by mass, respectively, the coated lead storage battery was produced under the same conditions as in Example 4-1.

(Examples 4-5～4-8) Except for setting the Se content to 0.001% by mass, the coated lead storage battery was produced under the same conditions as in each of Examples 4-1 to 4-4.

(Examples 4-9～4-12) Except that the Bi content was further set to 0.001% by mass, the coated lead storage battery was produced under the same conditions as in each of Examples 4-5 to 4-8.

(Examples 4-13～4-16) Except that the Sn content was further set to 0.001% by mass, the coated lead storage battery was produced under the same conditions as in each of Examples 4-9 to 4-12.

For the above-mentioned Examples 4-1 to 4-16, the castability, durability, and other various characteristics were confirmed and evaluated. The evaluation criteria are as described above. The results are shown in Table 4.

[Table 4]

According to Table 4, compared with Examples 4-1 to 4-4, in the case of Examples 4-5 and below that contain any one of Se, Bi, and Sn, the strength of the material is improved, especially containing 0.001% by mass of Se In Examples 4-13 to 4-16 of any of, Bi, and Sn, it can be seen that the castability becomes excellent.

From these results, it is confirmed that regardless of the amount of As contained in the lead alloy, by further including any of Se, Bi, and Sn in the lead alloy, it is possible to achieve castability and material without impairing other various characteristics. Increase in intensity.

Furthermore, it was confirmed whether the respective contents of Sb, As, Se, Bi, and Sn contained in the lead alloy are related to each other and affect various characteristics. The preparation conditions of each Example and Comparative Example are as follows.

(Example 5-1) Pressure casting was used as the casting form. As shown in Table 5, the Sb content was set to 3.5% by mass, the As content was set to 0.3% by mass, the Se content was set to 0.01% by mass, and the contents of Bi and Sn were set to It was set to 0.005 mass%, the average diameter of the core rod was set to 2.7 mm, and the established density was set to 3.65 g/cm ³ , and the covered lead storage battery was produced under the above-mentioned conditions.

(Example 5-2) Except that the Se content was set to 0.02% by mass, the coated lead storage battery was produced under the same conditions as in Example 5-1.

(Example 5-3) Except that the Se content was 0.03% by mass, the Bi content was 0.03% by mass, and the Sn content was 0.02% by mass, the covered lead storage battery was produced under the same conditions as in Example 5-1.

(Example 5-4) Except that the Sb content is set to 4% by mass, the As content is set to 0.1% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.01% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-5) Except that the Sb content is set to 4% by mass, the As content is set to 0.1% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-6) Except that the Sb content is set to 4% by mass, the As content is set to 0.45% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-7) Except that the Sb content is set to 4.5% by mass, the As content is set to 0.1% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-8) Except that the Sb content is set to 4.5% by mass, the As content is set to 0.45% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-9) Except that the Sb content is set to 5% by mass, the As content is set to 0.1% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-10) Except that the Sb content is set to 5% by mass, the As content is set to 0.45% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-11) Except that the Sb content is set to 6 mass%, the As content is set to 0.1 mass%, the Se content is set to 0.02 mass%, the Bi content is set to 0.02 mass%, and the Sn content is set to 0.02 mass%, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-12) Except that the Sb content is set to 6 mass%, the As content is set to 0.45 mass%, the Se content is set to 0.02 mass%, the Bi content is set to 0.02 mass%, and the Sn content is set to 0.02 mass%, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-13) Except that the Sb content is set to 7 mass%, the As content is set to 0.1 mass%, the Se content is set to 0.02 mass%, the Bi content is set to 0.02 mass%, and the Sn content is set to 0.02 mass%, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Example 5-14) Except that the Sb content is set to 7 mass%, the As content is set to 0.45 mass%, the Se content is set to 0.02 mass%, the Bi content is set to 0.02 mass%, and the Sn content is set to 0.02 mass%, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Comparative Example 5-1) Except that the Sb content is set to 7.5% by mass, the As content is set to 0.1% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

(Comparative Example 5-2) Except that the Sb content is set to 7.5% by mass, the As content is set to 0.45% by mass, the Se content is set to 0.02% by mass, the Bi content is set to 0.02% by mass, and the Sn content is set to 0.02% by mass, the same as in Example 5-1 The same conditions were used to make a coated lead storage battery.

For the above-mentioned Examples 5-1 to 5-14, material strength and other various characteristics were confirmed and evaluated. The evaluation criteria are as described above. The results are shown in Table 5.

[table 5]

According to Table 5, it is confirmed that compared with As, Se, Bi, and Sn, the content of Sb mainly affects the strength of the material. In the range of Se and Bi of 0.001% by mass or more and 0.03% by mass or less, Sn is 0.001% by mass or more In addition, within the range of 0.02% by mass or less, each makes the material strength excellent. In addition, it is not a problem to confirm that the total amount of Se, Bi, and Sn is about 0.08% by mass.

Then, the improvement of various characteristics in the case of using gravity casting as the casting method was verified. The preparation conditions of each comparative example are as follows.

(Comparative Example 6-1) Gravity casting was used as the casting form. As shown in Table 6, the Sb content was set to 3.5% by mass, the As content was set to 0.005% by mass, the Se content was set to 0.001% by mass, and the Bi content was set to 0.0005. Mass%, Sn content was set to 0.0005 mass%, the average diameter of the core rod was set to 2.7 mm, the established density was set to 3.65 g/cm ³ , and the covered lead storage battery was produced under the above-mentioned conditions.

(Comparative Example 6-2) Except that the Se content was 0.0005 mass% and the Bi content was 0.001 mass %, the covered lead storage battery was produced under the same conditions as in Comparative Example 6-1.

(Comparative Example 6-3) Except that the Se content was 0.0005 mass% and the Sn content was 0.001 mass %, the covered lead storage battery was produced under the same conditions as in Comparative Example 6-1.

(Comparative Example 6-4) Except that the Bi content was set to 0.001% by mass, the covered lead storage battery was produced under the same conditions as in Comparative Example 6-1.

(Comparative Example 6-5) Except that the Sn content was set to 0.001% by mass, the covered lead storage battery was produced under the same conditions as in Comparative Example 6-1.

(Comparative example 6-6) Except that the Se content was 0.0005 mass %, the Bi content was 0.001 mass %, and the Sn content was 0.001 mass %, the covered lead storage battery was produced under the same conditions as in Comparative Example 6-1.

(Comparative example 6-7) Except that the Bi content was 0.001% by mass and the Sn content was 0.001% by mass, the same conditions as in Comparative Example 6-1 were used to produce a coated lead storage battery.

For Comparative Examples 6-1 to 6-7, the results after confirming various characteristics are shown in Table 6.

[Table 6]

According to Table 6, it was verified that even if Se, Bi, and Sn are contained in the lead alloy in addition to Sb, as long as the casting method is gravity casting, a coated lead-acid battery with a high evaluation cannot be obtained.

As mentioned above, although the embodiment of the present invention, examples and comparative examples have been specifically described, the present invention is not limited to these embodiments and experimental examples. For example, the number and size of the covering member can be arbitrarily specified. That is, the aspects described in the above-mentioned embodiments and experimental examples can of course be changed based on the technical idea of the present invention unless otherwise stated.

[Industrial Utilization Possibility] According to the present invention, the current collector of the clad lead storage battery is manufactured by pressure casting a lead alloy containing a predetermined amount of antimony, and the castability and durability of the core rod can be maintained at the same time. In addition, it is possible to reduce the cross-sectional size of the core rod while maintaining castability and durability. Therefore, it is possible to provide a coated lead storage battery in which the thickness of the positive electrode plate for the coated lead storage battery is thin.

1: Coated tube 2: carrier 3: Groove 4: Upper connecting seat 5: Lower connecting seat 6: Mandrel 7: Lead powder 8: Connection part 9: Ears 15: Coated positive plate 19: Hole

Figure 1 (A) is a metal microscope photo, which shows the structure of the current collector (mandrel) of a coated positive electrode plate cast using conventional technology; Figure 1 (B) is a metal microscope photo, which shows The structure of the current collector (core rod) of the coated positive electrode plate used in the examples of the present invention. Fig. 2 is a schematic diagram of the manufacturing process of the coated positive electrode plate of the present embodiment.

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Claims (6)

A method of manufacturing the core rod of the current collector for the coated lead storage battery is to manufacture the core rod of the current collector for the coated lead storage battery with the core rod by the pressure casting method, the core rod is a lead alloy It is formed by casting, wherein the method includes the following steps: a step of melting the lead alloy, relative to the total mass of the aforementioned lead alloy, the lead alloy contains antimony in an amount of 3.0% by mass or more and 7.0% by mass or less, and the remainder is lead and Inevitable impurity; the step of sending the molten lead alloy into a mold that is pressurized with a clamping force of 2000-4000kN; and, the step of cooling and releasing the mold; use as the mold so that the average cross-sectional area of the mandrel becomes 4.9mm ² or more and 7.1mm ² or less of the mold, the average cross-sectional area of the cross section obtained by cutting through in a direction orthogonal to the longitudinal direction of the rod cross-sectional area It is obtained by averaging along the entire longitudinal axis of the aforementioned mandrel. The method for manufacturing a core rod of a current collector for a clad lead storage battery according to claim 1, wherein the content of the antimony is 4.0% by mass or more and 5.0% by mass relative to the total mass of the lead alloy. The method for manufacturing a core rod of a current collector for a coated lead storage battery according to claim 1, wherein the lead alloy further contains arsenic in an amount of 0.01% by mass or more and 0.40% by mass or less. The method for manufacturing a core rod of a current collector for a coated lead storage battery according to claim 1, wherein the lead alloy further contains arsenic in an amount of 0.01% by mass or more and 0.20% by mass or less. The method for manufacturing a core rod of a current collector for a clad lead storage battery according to claim 1, wherein the mold is a mold in which the cross-sectional profile of the core rod becomes a circular shape. The method for manufacturing a core rod of a current collector for a coated lead storage battery according to claim 5, wherein the mold is a mold in which the average diameter of the core rod is 2.5 mm or more and 3.0 mm or less, and the average diameter is The diameter of the cross section of the core rod is averaged along the longitudinal axis of the core rod.

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