JP2009272203A - Lead acid storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead acid storage battery capable of suppressing a stratification phenomenon of an electrolytic solution and attaining improvement in charging acceptance. <P>SOLUTION: The lead acid storage battery is provided with an electrode group 4 in which a positive electrode plate 1 having a positive electrode active material filled into a grid body and a negative electrode plate 2 having a negative electrode active material filled into a grid body are laminated through a separator 3. The positive electrode plate 1 is constituted of a first portion 101 which is formed thin throughout the horizontal direction and a second portion 102 which is formed thicker than the first portion throughout the horizontal direction, and the first portion 101 and the second portion 102 are arranged alternately in vertical direction of the electrode plate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lead-acid battery.

  For example, as shown in Patent Document 1, in a lead storage battery, a positive electrode plate made of a positive electrode active material filled in a lattice body and a negative electrode plate made of a negative electrode active material filled in a lattice body are separated into separators. The electrode plate group is configured by connecting the current collecting tabs (ears) of the positive electrode plate and the current collecting tabs of the negative electrode plate with the positive electrode strap and the negative electrode strap, respectively, and is provided in the battery case. A plurality of cells are configured by accommodating the electrode plate group together with the electrolyte in the plurality of cell chambers. And by connecting between adjacent cells by inter-cell connection parts, a plurality of cells are connected in series, and the positive electrode terminal and the negative electrode terminal respectively derived from the cells at both ends are led to the upper part through the lid of the battery case. Yes.

  Lead-acid batteries are widely used to drive a starting device for starting an automobile engine and various electrical components mounted on the automobile. In recent years, in the field of automobiles, in order to protect the environment and improve fuel efficiency, as shown in Patent Document 2, the engine is stopped when the vehicle is stopped and the engine is restarted when the vehicle is started (hereinafter referred to as ISS). Is abbreviated to be implemented). In ISS, starting and stopping of the engine are frequently repeated, and at the time of starting, a large current is discharged by the lead-acid battery. In addition, when the vehicle is stopped, the charging is stopped and power is supplied to the on-vehicle electrical component load. As a result, the amount of electricity discharged becomes very large.

  A lead-acid battery mounted on a vehicle that performs ISS is also charged at a constant voltage through a regulator with a rectified output of an AC generator driven by the vehicle, like a lead-acid battery mounted on a normal vehicle. In recent years, the set value of the charging voltage tends to be lowered in order to minimize the decrease in the electrolyte due to water decomposition during use. Recently, vehicles called charge control vehicles have been used. In this type of vehicle, in addition to low charging voltage, a method of changing the charging voltage according to the load of the vehicle driving engine is adopted. It has come to be.

In an engine-driven vehicle that performs ISS and a charge control vehicle, since it is difficult to charge the battery, there is a problem that the battery is difficult to be completely charged. Under such usage conditions, the lead-acid battery is not sufficiently charged, so the battery is often used in an excessively discharged state.
JP 9-31155 A JP 2006-210134 A

  When the charge / discharge cycle is repeated in the state as described above, a part that is frequently used and a part that is not frequently used in the electrode plate in the lead storage battery are generated, and the upper part of the electrode plate close to the part of the current collecting tab for taking out the current There is a difference in the utilization factor of the active material between the lower part of the electrode plate away from the current collecting tab. For this reason, charging and discharging are repeated at the lower part of the electrode plate, resulting in insufficient charging, and accumulation (sulfation) of discharge products (lead sulfate) occurs on the surface of the electrode plate. In such a state, since it becomes difficult to oxidize and reduce at the lower part of the electrode plate, the battery performance deteriorates.

  In a situation where charging is not completely performed, a stratification phenomenon occurs in which the concentration of the electrolytic solution is thin at the top and thick at the bottom, further promoting sulfation.

  When the electrolyte stratification phenomenon occurs, sulfation occurs mainly in the lower part of the battery, the reaction becomes uneven between the upper and lower parts of the electrode plate, and the reaction mainly occurs only at the upper part of the electrode plate. . In this case, with respect to the positive electrode plate, the active material is peeled off from the lattice at the upper portion thereof, which leads to an early deterioration of the battery performance and shortens the battery life. Therefore, in a lead storage battery mounted on a vehicle that performs ISS, it is necessary to suppress the stratification phenomenon of the electrolyte as much as possible.

  In addition, when the supply of the charging current from the generator is frequently stopped as in the case of performing ISS, it is necessary to perform charging in a short time so as not to cause a shortage of battery capacity. There is a need to improve battery charge acceptance. However, if sulfation occurs as described above and a reaction occurs mainly only at the upper part of the electrode plate, it is inevitable that the charge acceptability deteriorates.

  An object of the present invention is to provide a lead-acid battery capable of suppressing the stratification phenomenon of an electrolytic solution and improving charge acceptability.

  The present invention relates to a lead-acid battery including an electrode plate group in which a positive electrode plate formed by filling a positive electrode active material in a lattice and a negative electrode plate formed by filling a negative electrode active material in a lattice through a separator. In the present invention, in the present invention, at least one of the positive electrode plate and the negative electrode plate is formed over the entire lateral direction of the first plate and the entire lateral direction of the electrode plate. And a second portion formed to be thicker than the first portion, and the first portion and the second portion are provided alternately in the longitudinal direction of the electrode plate.

  For example, after the grid material is filled with an active material, the first portion is pressed by a roller hook on the portion to be the first portion of the electrode plate, and the thickness thereof is smaller than the thickness of the second portion. Can be formed.

  In the present specification, the direction along the vertical direction in the battery case of the electrode plate is the vertical direction, and the direction perpendicular to both the vertical direction and the thickness direction of the electrode plate is the horizontal direction of the electrode plate.

  As described above, at least one of the positive electrode plate and the negative electrode plate is thicker than the first portion over the entire length in the lateral direction and the first portion formed with a small thickness over the entire length in the lateral direction. When the first portion and the second portion are alternately arranged in the vertical direction, the second portion having a large thickness becomes a gap between the electrode plates ( Strictly speaking, a convex portion is formed that protrudes into the gap between the electrode plate constituted by the first part and the second part of the adjacent electrode plates and the separator interposed between the adjacent electrode plates. And since this convex part partitions the clearance gap between electrode plates up and down, it can suppress that a part with large specific gravity of electrolyte solution moves below. In addition, since the thickness of the first portion is thin, the distance between the average electrode plates is increased, so that the flow of the electrolyte can be promoted and the electrolyte having a large specific gravity can be prevented from staying in the lower part of the battery. Thus, it is possible to suppress the occurrence of stratification of the electrolytic solution and to prevent sulfation from occurring in the lower part of the electrode.

  Therefore, it is possible to prevent the reaction between the upper part and the lower part of the electrode plate from becoming uneven and the reaction from occurring only at the upper part of the electrode plate. As a result, it is possible to prevent the battery performance from deteriorating at an early stage and improve the battery charge acceptance.

  The electrode plate having the first portion and the second portion is preferably formed so that the uppermost portion is the first portion having a small thickness.

  As described above, if the portion located at the top of the electrode plate is the first portion having a small thickness and the distance between the electrode plates at the upper part of the electrode plate is widened, the fluidity of the electrolyte is improved. Therefore, the difference in concentration between the upper and lower electrolytes in the battery case can be reduced, and the occurrence of the stratification phenomenon of the electrolyte can be suppressed.

  In a preferred aspect of the present invention, the first portion is formed by compressing (pressing) a part of the electrode plate in the thickness direction to reduce the thickness.

  As described above, when the first portion is formed by compressing a part of the electrode plate in the thickness direction to reduce the thickness, the bonding between the particles of the active material can be strengthened. It can be prevented from occurring, and the battery life can be prevented from being shortened by peeling of the active material.

  As described above, when the first part and the second part are formed by compressing (pressing) a part of the electrode plate in the thickness direction to reduce the thickness, the first part and the second part The positive electrode plate is preferably a positive electrode plate in which the active material is easily peeled off.

  According to the present invention, at least one of the positive electrode plate and the negative electrode plate has a first portion formed with a thin thickness over the entire length in the lateral direction and a thickness greater than the first portion over the entire length in the horizontal direction. Since the first portion and the second portion are alternately arranged in the vertical direction, the gap between the electrode plates is formed by the thick second portion. By partitioning the upper and lower parts, it is possible to suppress a portion where the specific gravity of the electrolytic solution is large from moving downward, and it is possible to prevent a large difference in the concentration of the electrolytic solution between the upper part and the lower part in the battery.

  In addition, since the average distance between the electrode plates is increased by reducing the thickness of the first portion of the electrode plate, the fluidity of the electrolyte solution in the battery is improved, and an electrolyte solution having a large specific gravity stays in the lower part of the battery. This can also prevent the difference in electrolyte concentration between the upper and lower parts between the electrode plates.

  Therefore, according to the present invention, since stratification of the electrolyte can be suppressed and sulfation can be prevented from occurring at the lower part of the electrode, it is possible to prevent a reaction from occurring only at the upper part of the electrode plate. It is possible to prevent the active material from peeling off at the upper part of the positive electrode plate at an early stage and shortening the battery life.

  Furthermore, the active material is compressed in the thickness direction at the first portion of the electrode plate, and the active material particles are firmly bonded to each other, so that the active material can be made difficult to peel off, thereby extending the life of the battery. can do.

  In addition, according to the present invention, sulfation is less likely to occur in the lower part of the electrode plate, and the reaction can be performed in both the upper part and the lower part of the electrode plate, so that the charge acceptability of the battery can be improved.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
As described above, in the present invention, at least one of the positive electrode plate and the negative electrode plate has the first portion formed thin in the entire lateral direction of the electrode plate and the entire lateral direction of the electrode plate. A second portion formed thicker than the first portion, and the first portion and the second portion are provided so as to be alternately arranged in the longitudinal direction of the electrode plate. Yes.

  1A and 1B are a front view and a right side view schematically showing a positive electrode plate 1 used in this embodiment, respectively. The positive electrode plate 1 used in the present embodiment extends in parallel with two strip-shaped first portions 101 (parts that appear light-colored in the drawing) that extend in parallel to the lateral direction of the electrode plate, and also in the horizontal direction of the electrode plate. The first portion 101 and the second portion 102 are arranged so as to be alternately arranged in the vertical direction of the electrode plate. The first portion 101 and the second portion 102 are provided so that the first portion 101 is disposed at the top of the electrode plate and the second portion 102 is disposed at the bottom of the electrode plate, The first portion 101 is formed to have a thickness thinner than that of the second portion 102.

  In the positive electrode plate, after the active material is filled in the lattice body, when the active material is hardened by compressing the electrode plate with a roller, the amount of compression in the portion to be the first portion 101 is set to the second portion 102. It can produce by making it larger than the compression amount in the part which should be.

  In this embodiment, since the first portion 101 and the second portion 102 are formed by pressing the positive electrode plate with a roller from one side, as shown in FIG. The first portion 101 and the second portion 102 form concave portions r and convex portions p only on one surface of the positive electrode plate 1 and these are alternately arranged in the longitudinal direction of the electrode plate.

  In FIG. 1, a portion denoted by reference numeral 1a is a current collecting tab (ear portion) formed integrally with the lattice body on the upper portion of the lattice body (not shown).

  On the other hand, the negative electrode plate used in the present embodiment is formed so as to have a substantially uniform thickness as a whole after the lattice material is filled with an active material and then uniformly compressed by a roller.

  FIG. 2 shows a part of the electrode plate group 4 formed by laminating the positive electrode plate 1 obtained as described above and the negative electrode plate 2 having a uniform thickness with a separator 3 interposed therebetween. In FIG. 2, reference numeral 2 a denotes a current collecting tab provided on the grid body of the negative electrode plate 2. The current collecting tabs 1a of the series of positive electrode plates constituting the electrode plate group are connected to each other by a positive electrode strap (not shown), and the current collecting tabs 2a of the series of negative electrode plates 2 are connected to each other by a negative electrode strap. As apparent from FIG. 2, in this embodiment, the convex portion p formed by the second portion 102 of the positive electrode plate 1 has a gap between the adjacent positive electrode plate 1 and negative electrode plate 2 (strictly speaking, Projecting into the gaps (g) between each positive electrode plate 1 and the separator 3 facing the positive electrode plate, the gap g between adjacent electrode plates is partitioned into a plurality of regions in the vertical direction.

  When the gap between the electrode plates is partitioned into a plurality of regions above and below in this way, the concentration of the electrolyte is reduced at the upper part in the battery case, compared to the case where the gap between the electrode plates is not partitioned, Since the electrolyte concentration in the lower part of the battery case is increased and the stratification phenomenon of the electrolyte can be suppressed, the occurrence of sulfation is suppressed in the lower part of the electrode plate. The battery reaction can be performed substantially uniformly even at the lower part, and the active material can be prevented from deteriorating early due to peeling of the active material from the lattice at the upper part of the positive electrode plate. In addition, since the battery reaction can be performed almost uniformly on both the upper and lower sides of the electrode plate, the battery charge acceptability can be improved. Examples of the present invention and comparative examples will be described below.

  In this example, an active material paste was obtained by adding water and dilute sulfuric acid to lead powder made of lead oxide and kneading. After filling this paste into the lead grid, using a roller having a large diameter portion for forming the first portion 101 of the positive electrode plate and a small diameter portion for forming the second portion 102, By rolling the roller along one side of the plate along the lateral direction, as shown in FIG. 1, two first portions 101, 101 extending in parallel to the lateral direction of the electrode plate, and the first portion The positive electrode plate 1 was manufactured by forming the second portions 102 and 102 having a large thickness. In this embodiment, the thickness of the first portion 101 falls within the range of 1.4 mm to 1.6 mm, and the thickness of the second portion 102 falls within the range of 1.6 mm to 1.9 mm.

  Further, the negative electrode plate was manufactured to have a thickness of approximately 1.3 mm by filling the grid with paste and then uniformly rolling the electrode plate to uniformly compress the entire plate.

  After the positive electrode plate 1 and the negative electrode plate 2 obtained as described above are aged and dried, the positive electrode plate 1 and the negative electrode plate 2 are laminated via the separator 3, and the current collecting tabs of the positive electrode plate and the negative electrode plate are laminated. A positive electrode strap and a negative electrode strap for connecting the current collecting tabs to each other were formed, and a large number of electrode plate groups 4 including seven positive electrode plates and eight negative electrode plates were produced. As the separator 3, a separator having a total thickness of 0.7 to 1.5 mm is usually used. In this embodiment, a separator having a total thickness of 0.7 mm was used. The electrode plate group having the same average electrode plate distance is selected from the large number of electrode plate groups 4 produced in this way, with the electrode plate distances being approximately 0.75 mm, 0.95 mm and 1.2 mm. A lead-acid battery having 6 cells with an electrode plate in an unformed state was assembled. The lead acid batteries of Examples using electrode plate groups having average electrode plate distances of about 0.75 mm, 0.95 mm, and 1.2 mm were referred to as Example 1, Example 2, and Example 3, respectively. The distance between the electrode plates is a distance between the surface of the concave portion r of the positive electrode plate and the surface of the negative electrode plate (depth of the concave portion r + thickness of the separator 3).

Comparative example

  Using a positive electrode plate having a uniform thickness (1.6 mm) as a whole and a negative electrode plate having a uniform thickness (1.3 mm) as a whole, a lead storage battery similar to the above example was assembled as a comparative example.

  The battery is formed by injecting an electrolytic solution (dilute sulfuric acid) into the battery case of the lead acid battery of the examples and comparative examples assembled as described above, and conducting a battery case, and a lead acid battery equivalent to 36 Ah as a 5-hour rate capacity. Was made.

  About the battery of Example 1 and a comparative example, it discharged so that SOC (charge condition) might be 90% at 25 degreeC, and after leaving it to stand for 6 hours, it performed constant voltage charge of 14.0V (100Amax) for 30 seconds, A charge acceptance test was conducted.

  From the results measured for the batteries of Example 1 and the comparative example, a charging curve as shown in FIG. 3 showing the relationship between the charging current and the charging time is created, and a comparison is made with the charging electric quantity at the fifth second from this charging curve. The relationship between the distance between the electrode plates and the charge acceptability was examined. FIG. 4 shows the result of comparing the relationship between the charge acceptance and the average distance between the electrode plates in Examples 1 to 3 by converting the charge electricity amount at the 5th second into the charge acceptance property (charged electricity amount) per reaction area. It was shown to. From this result, it became clear that the charge acceptability is improved by increasing the distance between the electrode plates.

  The “average distance between the electrode plates” on the horizontal axis in FIG. 4 is the average value of the distance between the concave surface of the positive electrode plate and the surface of the negative electrode plate, and is between the convex surface of the positive electrode plate and the surface of the negative electrode plate. (The thickness of the separator) and the distance between the concave surface of the positive electrode plate and the surface of the negative electrode plate are weighted averages by the ratio of the convex area to the concave area. In the example, the convex surface area: concave surface area = 4: 6 on one surface side of the positive electrode plate, and the convex surface area: concave surface area = 10: 0 on the other surface side of the positive electrode plate. The weighted average was performed with the ratio to the surface area of the recess being 14: 6.

Detailed data of Examples 1 to 3 and Comparative Example are shown in Table 1 below.

In Table 1, the equation for calculating the amount of charged electricity (Ah / cm ² ) is shown below using the data of Example 1.
(49A × 30sec) ÷ (10cm × 10cm × 2 / sheet × 7sheet / cell × 6cell × 3600sec) = 4.9 × 10 ⁻⁵ Ah / cm ²
In the above formula, “10 cm × 10 cm” indicates the size of the positive electrode plate, “2 / sheet” indicates that the calculation is performed on both the front and back surfaces, and “7 sheets / cell” indicates the positive electrode plate per cell. Indicates the number of sheets.

  Next, the light load test defined by JIS was performed on the lead storage batteries of Examples 1 to 3 and the lead storage battery of the comparative example. In this test, the discharge and charge were repeated with one cycle consisting of a constant current discharge of 25 A for 4 minutes and then a constant voltage charge of 14.8 V (25 Amax) for 10 minutes. Then, 430 A was discharged every 480 cycles, the voltage at the 30th second was measured, and the time when the voltage at the 30th second fell below 7.2V was regarded as the life. The results of this light load test are shown in FIG. As is clear from FIG. 5, the cycle life of each of the examples is improved as compared with the comparative example.

  The reason why the charge acceptability and the cycle life are improved as described above is considered as follows. That is, the first electrode portion 101 of the positive electrode plate increases the distance between the electrode plates, thereby improving the fluidity of the electrolyte solution, thereby preventing the portion having a high specific gravity of the electrolyte solution from staying in the lower part of the battery. Can do. Moreover, it can suppress that the part with large specific gravity of electrolyte solution moves below because the clearance gap between electrode plates is divided up and down by the convex part p formed by the 2nd part of a positive electrode plate, and these. The difference between the electrolytic solution concentration at the upper part of the battery and the electrolytic solution concentration at the lower part can be reduced, and stratification of the electrolytic solution can be suppressed. Therefore, it is possible to suppress the occurrence of sulfation at the lower part of the electrode, and it is possible to prevent the reaction from occurring only at the upper part of the electrode plate and the separation of the active material at the upper part of the positive electrode plate. In addition, since the reaction can be performed at the upper part or the lower part of the electrode plate, the charge acceptability can be improved.

  In the above example, only the positive electrode plate is composed of the first portion and the second portion. However, as shown in FIG. 6, the positive electrode plate 1 is composed of the first portion 101 having a small thickness and the second portion having a large thickness. The negative electrode plate 2 may be configured by the first portion 201 having a small thickness and the second portion 202 having a large thickness.

  Further, only the negative electrode plate may be constituted by the first portion and the second portion, and the positive electrode plate may be constituted so as to have a uniform thickness.

(A) And (b) is the front view and right view which each showed typically the positive electrode plate used by embodiment of this invention. It is the side view which showed typically a part of electrode group comprised using the positive electrode plate of FIG. 1, and the negative electrode plate which has uniform thickness. It is a graph which shows the charge curve created based on the measurement result obtained by the experiment which investigates the charge acceptance of an Example and a comparative example. It is the graph which compared and showed the relationship between the charge acceptance of Example 1 thru | or 3 of this invention, and the average distance between electrode plates. It is the graph which showed the result of the light load test done about Example 1 thru | or 3 of this invention, and the comparative example. It is the side view which showed typically a part of electrode group used with the lead storage battery concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode plate 101 1st part 102 2nd part 2 Negative electrode plate 3 Separator 4 Electrode plate group

Claims (3)

In a lead storage battery comprising an electrode plate group in which a positive electrode plate formed by filling a positive electrode active material in a grid and a negative electrode plate formed by filling a negative electrode active material in a lattice through a separator,
At least one of the positive electrode plate and the negative electrode plate is thinner than the first part and the first part formed to have a small thickness over the entire lateral direction of the electrode plate and the first part over the entire lateral direction of the electrode plate. Has a second portion formed thick,
The lead acid battery according to claim 1, wherein the first part and the second part are provided so as to be alternately arranged in the longitudinal direction of the electrode plate.   The lead storage battery according to claim 1, wherein the first portion is formed by pressing a part of the electrode plate in the thickness direction to reduce the thickness.   3. The lead acid battery according to claim 1, wherein the electrode plate having the first part and the second part is formed such that a part located at the uppermost part is formed of the first part. 4.

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