JP2006059671A - Lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead-acid battery suppressing internal short circuit caused by curving of an electrode plate generating in the lead-acid battery housing expand electrode plates in a bag-shaped polyethylene separator, enhancing productivity, and lengthening life. <P>SOLUTION: The lead-acid battery uses positive plates 601 and negative plates 602 in which a positive plate surface and a negative plate surface are curved so as to project in the opposite direction to the pressing in direction of a cutting blade in cutting work of the expand electrode plates, and the curved directions of the positive plates and the negative plates constituting an electrode plate group are made the same. Preferably, the positive plate is manufactured in such a way that an active material is filled in an over-paste state, and the cutting blade is pressed into one surface from the over-paste surface of the electrode plate and cut so that the electrode plate is made thicker than an expand grid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead-acid battery.

  As a lattice used for a lead storage battery, a cast lattice and an expanded lattice are mainly known. The cast lattice is obtained by injecting molten lead into a book mold type lattice mold or a drum-shaped continuous cast mold and cooling and solidifying it. The expanded lattice body is obtained by developing slits formed in a staggered pattern on a long lead or lead alloy sheet in a mesh shape.

  It is necessary for the cast lattice body to secure a molten lead flow in the lattice mold and to ensure that the lattice thickness is as thick as possible so that defects such as lattice fractures do not occur. The lower limit of the thickness varies depending on the lattice alloy composition, but the practical limit is approximately 1.5 mm when considering the process defect rate and the like. Therefore, when manufacturing an electrode plate using this cast grid, it is extremely difficult to make the thickness less than about 1.5 mm.

  On the other hand, the thickness of the expanded lattice body can be adjusted by the thickness of the lead alloy sheet used as the material, the gap dimension (cut width) between the slits, and the gap between the thickening rollers of the expanded mesh, and a thin lattice having a thickness of 1.5 mm or less. The body also has the advantage that it can be created with good productivity. Therefore, such a thin expanded lattice body is widely used in start lead-acid batteries that require high output.

  As shown in FIG. 1, the expanded lattice manufacturing process forms a staggered slit 103 on both sides, leaving the plain portion 102 at the center of the lead alloy sheet 101. The slit 103 is developed in the width direction of the lead alloy sheet 101 to form an expanded mesh 104 to obtain a long expanded lattice 107. The expanded mesh 104 includes a lattice bone 105 and a knot portion 106 that connects the lattice bone 105.

Since the expanded mesh 104 has undulations and waves, the elongate expanded lattice 107 is passed through a pair of thickness adjusting rollers (not shown) having a predetermined gap to adjust the thickness of the lattice. . Thereafter, the expanded mesh 104 is filled with the active material 109 to obtain a long electrode plate 110. In order to prevent the active material from falling off, paste paper (not shown) is attached to the long electrode plate 110 as necessary. Thereafter, the long electrode plate 110 is cut into a predetermined length, and the uncoated portion 102 is processed to form the electrode plate ear 111 to form a single electrode plate 112. At that time, the electrode plate ear may be warped. For example, Patent Document 1 discloses an apparatus for correcting the electrode plate ear warp.
JP-A-5-205731

  When the long electrode plate 110 is cut into a single electrode plate 112, the electrode plate 112 may bend in addition to the above-described warpage of the electrode plate depending on the cutting method. In particular, as shown in FIG. 2, the long electrode plate 110 is positioned on the anvil 201, and the cutting blade 202 having the cutting edge angle (α) is directed to the long electrode plate 110 from one direction toward the anvil 201. It may be pressed and cut. In such a case, as shown in FIG. 3, the electrode plate 112 is curved in a convex shape in a direction opposite to the press-fitting direction of the cutting blade 202 in most cases. When the electrode plate is curved, it is very difficult to remove the curve even if the electrode plate is passed through the rod-shaped roller disclosed in Patent Document 1. In addition, even if the thickness adjusting press is performed at a pressure that does not damage the electrode plate, the electrode plate 112 is only elastically deformed, and when the thickness adjusting press is released, it is restored to the original curved state. End up. Furthermore, when the pressure of the thickening press is increased, the expanded lattice body is plastically deformed, and the predetermined electrode plate thickness cannot be obtained, the density and moisture content of the active material paste fluctuate, characteristics such as battery capacity and life characteristics There has been a problem in that variations have occurred and predetermined characteristic values cannot be obtained. Therefore, it has been extremely difficult to correct the curvature of the expanded electrode plate once curved.

  On the other hand, there is a method in which a long electrode plate 110 is disposed on a die 401 and punched and cut by a punch 402 as in the press cutting process shown in FIG. In such a method, since the punched electrode plate 112 is dropped downward, there is a problem that the electrode plate 112 is easily deformed particularly when the electrode plate 112 is thin.

  As shown in FIG. 5, an anvil roller 501 in which an anvil 503 is arranged on the circumference is used as a method of press-fitting the long pole plate 110 with a cutting blade 202 toward the anvil 201 shown in FIG. By using the cutting blade roller 502 on which the cutting blade 504 is disposed and passing the elongated electrode plate 110 between these roller pairs, the expanded electrode plate can be cut with relative ease and high productivity.

  However, when a lead storage battery is manufactured using a curved electrode plate as shown in FIG. 3, there is a problem that a short life is caused by an internal short circuit. In particular, the end of the cut lattice bone 105 is exposed on the cut surface 301 of the electrode plate using the expanded lattice body, and the tip of the lattice bone 105 penetrates the separator, and the frequency of internal short-circuiting increases.

  Such a penetration of the separator and an internal short circuit due to this penetration are problems that occur remarkably when the electrode plate is stored in a bag-like polyethylene separator.

  In addition, when the active material 109 is filled in the long expanded lattice 107, an active material filled so as to exceed the thickness of the expanded lattice 107, so-called over paste, may be generated. In particular, in the positive electrode, when a cutting blade is press-fitted from the electrode plate surface where this over paste is generated (hereinafter referred to as the over paste surface) to the other electrode plate surface, the amount of bending increases during use of the battery. There was a problem of causing a short circuit.

  The present invention provides a lead-acid battery with high productivity and long life by suppressing the internal short circuit of the battery due to the curvature of the electrode, which occurs in the lead-acid battery using the expanded electrode plate as described above.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention expands both side portions in the width direction while leaving a plain portion in the width direction center portion of the long lead or lead alloy sheet. The obtained long expanded grid is filled with an active material to form a long electrode plate, and a cutting blade is press-fitted from one surface of the long electrode plate so that the long electrode plate has a predetermined length. A positive electrode plate and a negative electrode plate obtained by cutting the electrode plate, storing a positive electrode plate and a negative electrode plate in a bag-like polyethylene separator, and laminating together with the other electrode plate; The positive electrode plate and the negative electrode plate constituting the electrode plate group, wherein the positive electrode plate surface and the negative electrode plate surface are curved in a convex shape in a direction opposite to the press-fitting direction of the cutting blade. It shows a lead storage battery characterized by having the same bending direction .

  The invention according to claim 2 of the present invention is the lead-acid battery according to claim 1, and in the positive electrode plate, the active material is filled with an over paste exceeding the thickness of the expanded lattice, and the over paste of the positive electrode plate A lead-acid battery characterized in that the surface is curved with a convex surface.

  Furthermore, the invention according to claim 3 of the present invention is the lead storage battery according to claim 1 or 2, wherein the positively curved surface of the positive electrode plate and the negative electrode plate are placed on a virtual plane with the convex surface as an upper side, When a value (Ht) obtained by subtracting the thickness (t) of each of the positive electrode plate and the negative electrode plate from the distance (H) from the virtual plane to the convex apex is defined as an amount of curvature (D), The ratio (D / W) of the bending amount (D) to the positive electrode plate and negative electrode plate width (W) is 0.007 or more.

  According to the above-described configuration of the present invention, it is possible to suppress a battery internal short circuit due to electrode plate bending, which occurs in a lead storage battery using an expanded electrode plate, and to provide a highly productive and highly reliable lead storage battery. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the expanded lattice used in the lead storage battery of the present invention forms the slits 103 in a staggered manner on both sides, leaving the plain portion 102 at the center of the lead alloy sheet 101. The slit 103 is developed in the width direction of the lead alloy sheet 101 to form an expanded mesh 104 to obtain a long expanded lattice 107. The expanded mesh 104 includes a lattice bone 105 and a knot portion 106 that connects the lattice bone 105.

  Since there may be undulations and waviness in the expanded mesh 104, the elongated expanded lattice 107 is interposed between a pair of thickness adjusting rollers (not shown) having a predetermined gap as necessary. Pass through and adjust the thickness of the grid. Thereafter, the expanded mesh 104 is filled with the active material 109 to obtain a long electrode plate 110. In order to prevent the active material from falling off, paste paper (not shown) is attached to the long electrode plate 110 as necessary.

  Next, as shown in FIG. 2, the long electrode plate 110 is positioned on the anvil 201, and the cutting blade 202 having a cutting edge angle (α) is directed from one direction toward the anvil 201, and the long electrode plate The long electrode plate 110 is cut into a single electrode plate 112 by press-fitting into the electrode 110. In this state, the electrode plate 112 is convexly curved in the direction opposite to the press-fitting direction of the cutting blade 202 as shown in FIG.

  After cutting into a single electrode plate 112, these electrode plates 112 are aged and dried to produce an unformed electrode plate. Needless to say, the positive electrode and the negative electrode are classified according to the active material 109 filled in the long expanded lattice 107. Further, the lattice alloy composition may be selected according to various characteristics required for the positive electrode and the negative electrode. For example, since corrosion resistance is required for the positive electrode, a Pb—Ca—Sn alloy containing about 1.0 to 2.0 wt% of Sn and about 0.05 to 0.08 wt% of Ca can be used. On the other hand, since the corrosion resistance required for the positive electrode is not considered important for the negative electrode, a Pb—Ca—Sn alloy in which the content of Sn, which is more expensive than Pb, is reduced can be used.

  The unformed positive electrode plate 601 (the electrode plate 112 filled with a positive electrode active material as an active material) and the negative electrode plate 602 (the electrode plate 112 filled with a negative electrode active material as an active material) obtained above. The electrode plate group 600 is formed by laminating via a polyethylene bag-like separator 603. And the lead storage battery of this invention can be obtained by assembling a lead storage battery according to a regular method using this electrode group. In the present invention, as shown in FIG. 6, the bending directions of the positive electrode plate 601 and the negative electrode plate 602 constituting the electrode plate group 600 are the same direction. By making the bending direction the same direction, it is possible to prevent the separator from being damaged at the tips of the lattice bones exposed on the both sides of the positive electrode plate 601 and the negative electrode plate 602, and to suppress the occurrence of a battery internal short circuit.

  In particular, when using a configuration in which one of the positive electrode plate 601 and the negative electrode plate 602 is accommodated by a polyethylene bag-like separator 603, the frequency of damaging the separator at the tip of the lattice bone becomes higher. A remarkable effect can be obtained in the lead storage battery in which the electrode plate is accommodated in the separator.

  Also, in the positive electrode plate 601, as shown in FIG. 7, the positive electrode active material 604 is filled with over paste beyond the thickness of the expanded lattice 605, and is curved with the over paste surface 601a of the positive electrode plate 601 as a convex surface. In this case, the amount of bending increases due to the volume change of the positive electrode active material that occurs during use of the battery, and the frequency of occurrence of internal short circuits increases. Even when such an overpaste surface corresponds to a curved convex surface, by applying the present invention, a battery internal short circuit can be suppressed. When the cutting blade 202 is press-fitted from the overpaste surface 601a of the positive electrode plate 601, the overpaste surface 601a becomes a curved convex surface.

  From the relationship between the amount of bending of the electrode plate and the frequency of occurrence of internal short circuit, when the amount of bending exceeds a certain value, that is, as shown in FIG. 8, the positive electrode plate 601 and the negative electrode plate 602 are bent in a convex shape. The surface is placed on the virtual plane A, and the value (H) obtained by subtracting the thickness (t) of each of the positive electrode plate and the negative electrode plate from the distance (H) from the virtual plane A to the convex apex B. The configuration of the present invention when the ratio (D / W) of the bending amount (D) to the positive electrode plate and negative electrode plate width (W) is 0.007 or more, where -t) is the bending amount (D). Is preferably used. This is because when the ratio (D / W) is 0.007 or more, the frequency of breakage of the separator and the internal short circuit due to the breakage increases rapidly.

  Hereafter, the battery by this invention and the battery by a comparative example were created, and the lifetime test was done.

1) As described in the embodiment, the rolled lead alloy sheet of the positive electrode plate Pb-0.06 wt% Ca-1.6 wt% Sn alloy is expanded, filled with the positive electrode active material paste, and the long electrode A board was created. Then, as shown in FIG. 2, the cutting blade was press-fitted into a long electrode plate, cut and processed, and after aging and drying, an unformed positive electrode plate was obtained. Here, the thickness of the expanded lattice was 1.3 mm. Also, the positive electrode plate A having the same thickness as the expanded lattice body after filling the active material and the thickness of the electrode plate after filling the active material was set to 1.5 mm, thereby setting the over paste thickness to 0.2 mm. A positive electrode plate B was prepared. In both the positive electrode plate A and the positive electrode plate B, the ratio of the bending amount to the electrode plate width (W) (D / W) was 0.002 to 0.050. Moreover, the positive electrode plate B was a positive electrode plate with the over paste surface side curved in a convex shape as shown in FIG. 7 by press-fitting a cutting blade from the over paste surface side.

2) The negative electrode plate Pb-0.06 wt% Ca-0.3 wt% Sn alloy rolled lead alloy sheet was expanded as described in the embodiment, filled with the negative electrode active material paste, and the long electrode A board was created. Then, as shown in FIG. 2, the cutting blade was press-fitted into a long electrode plate, cut and processed, and after aging and drying, an unformed positive electrode plate was obtained. Here, the thickness of the expanded lattice was 1.0 mm. The electrode plate thickness after filling the active material was the same as the expanded lattice thickness. The curvature ratio (D / W) of this negative electrode plate was 0.002 to 0.050.

  A starting lead-acid battery (12V48Ah) was prepared with the configuration shown in FIG. 9 using the above five positive electrode plates and five negative electrode plates. As shown in FIG. 6, the battery of the example of the present invention has the same bending direction of the positive electrode plate 601 and the negative electrode plate 602 constituting the electrode plate group 600. As shown in FIG. 10, the battery of the comparative example has a configuration in which the positive electrode plate 601 and the negative electrode plate 602 constituting the electrode plate group 700 do not have the same bending direction. A polyethylene bag-shaped separator 603 was used as the separator, and the negative electrode plate 602 was accommodated in the bag-shaped separator 603.

  The light load life test was conducted in the gas phase of 75 ° C. for the battery of the present invention and the battery of the comparative example shown in FIG. The life test conditions are as follows.

1) Discharge 25A x 4 minutes
2) Charging 14.8V (maximum current 25A) x 10 minutes
3) Judgment discharge 356A × 30 seconds The judgment discharge of 3) was performed every 480 cycles of the charge / discharge cycle of 1) 2) above, and the point of time when the discharge end voltage at the judgment discharge dropped to 7.2V was regarded as the life. The life test results of these inventive examples and comparative examples are shown in FIG. In addition, the life test result was shown by the percentage when the life cycle number of the battery A1 of the present invention example is 100.

  From the results shown in FIG. 9, it can be seen that the battery of the example of the present invention has a life characteristic superior to that of the battery of the comparative example. In addition, when the battery after the end of the life test was disassembled and inspected, the battery of the comparative example had a linear crack at the portion sandwiched between the positive electrode side and the negative electrode side of the bag-like separator, and an internal short circuit occurred at this part. Had occurred. On the other hand, the battery according to the example of the present invention had no damage to the bag-like separator, and reached the end of its life due to corrosion of the positive electrode lattice and softening and dropping of the positive electrode active material.

  Furthermore, in the battery of the comparative example, the battery using the positive electrode plate B tended to have a shorter life than other batteries. In addition, the batteries D1, B2, D3, and D4 have an increased amount of bending of the positive electrode plate after the end of the life test, and it is considered that the separator was damaged earlier and reached an internal short circuit. On the other hand, the battery B1, the battery B2, the battery B3, and the battery B4 of the example of the present invention using the positive electrode plate B have extremely good life characteristics and are superior to the battery of the example of the present invention that uses the positive electrode plate A. showed that. This is because the internal short circuit was suppressed in the battery of the example of the present invention, so that the battery B1, the battery B2, the battery B3, and the battery B4 using the positive electrode plate B with a larger amount of the positive electrode active material used the positive electrode plate A. It is considered that the depth of discharge with respect to the amount of the positive electrode active material is shallower than that of A1, battery A2, battery A3, and battery A4.

  Furthermore, it can be seen from the results shown in FIG. 9 that regarding the battery of the comparative example, the life tends to be abruptly reduced in the region where the curvature ratio (D / W) is 0.007 or more. On the other hand, the battery of the present invention example had excellent life characteristics even in the region where the ratio (D / W) was 0.007 or more. Therefore, the structure of the present invention can obtain a relatively more remarkable effect particularly when applied to an electrode plate having a ratio (D / W) of 0.007 or more.

  Since the present invention can suppress a short life due to internal short-circuiting of a lead storage battery using a thin expanded grid, which is likely to bend, lead for starting using a thin electrode plate is required because of high output. It is particularly suitable for a storage battery.

Diagram showing the expansion process Diagram showing the electrode plate cutting process Diagram showing the curved state of the electrode plate Diagram showing the electrode plate cutting process Diagram showing the electrode plate cutting process The figure which shows the electrode plate group cross section of the lead acid battery of this invention Figure showing a cross section of the positive electrode plate The figure which shows the curved state of a positive electrode plate (negative electrode plate) The figure which shows the battery structure of a present invention example and a comparative example, and a lifetime test result The figure which shows the electrode plate group cross section of the lead acid battery of a comparative example

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Lead alloy sheet 102 Plain part 103 Slit 104 Expanded mesh 105 Lattice bone 106 Nodal part 107 (Long form) expanded lattice body 109 Active material 110 Elongate electrode plate 111 Electrode plate ear 112 Electrode plate 201 Anvil 202 Cutting blade 301 Cutting surface 401 Die 402 Punch 501 Anvil roller 502 Cutting blade roller 503 Anvil 504 Cutting blade 600 Electrode plate group 601 Positive electrode plate 601a Over paste surface 602 Negative electrode plate 603 Bag-like separator 604 Positive electrode active material 605 Expanded grid body 700 Electrode plate group A Virtual Plane B apex

Claims (3)

A long electrode plate with an active material filled in a long expanded lattice obtained by expanding both sides of the long lead or lead alloy sheet in the width direction, leaving a plain portion in the width direction center. age,
A positive electrode plate and a negative electrode plate obtained by press-fitting a cutting blade from one surface of the long electrode plate and cutting the long electrode plate into a predetermined length,
A lead storage battery comprising an electrode plate group in which one of the positive electrode plate and the negative electrode plate is housed in a bag-like polyethylene separator and laminated together with the other electrode plate,
The positive electrode plate surface and the negative electrode plate surface are curved in a convex shape in a direction opposite to the press-fitting direction of the cutting blade,
A lead storage battery characterized in that the positive electrode plate and the negative electrode plate constituting the electrode plate group have the same bending direction. In the positive electrode plate, the active material is filled with an over paste so that the thickness of the positive electrode plate is larger than the thickness of the expanded lattice, and the cutting blade is press-fitted from the over paste surface of the positive electrode plate to the other surface. Lead-acid battery characterized by being cut. The positively curved surface of the positive electrode plate and the negative electrode plate is placed on a virtual plane with the upper surface being upward, and each of the positive electrode plate and the negative electrode plate is determined from the distance (H) from the virtual plane to the convex vertex. The ratio (D / W) of the bending amount (D) to the positive electrode plate and negative electrode plate width (W) is 0 when the value (Ht) obtained by subtracting the thickness (t) of the film is defined as the bending amount (D). The lead-acid battery according to claim 1 or 2, wherein the lead-acid battery is 0.007 or more.

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