JP6572711B2 - Lead acid battery - Google Patents

Description

  The present invention relates to a lead storage battery.

Applications for using lead-acid batteries in an incompletely charged state (PSOC (Partial state of charge)) are increasing.
For example, in an idling stop vehicle (IS), the fuel consumption is reduced by stopping the engine each time the vehicle is stopped, and the engine is started up with the electric power from the lead storage battery when starting. For this reason, lead acid batteries are used in a state of insufficient charging. In order to improve energy efficiency, not only for IS applications, charging to lead-acid batteries is avoided, and moreover, the electric power taken out from the lead-acid batteries is increasing, so that lead-acid batteries are often placed in an insufficiently charged state.

In a lead-acid battery, sulfuric acid is consumed at the bipolar plate during discharge, water is generated at the positive electrode, sulfuric acid is released from the bipolar plate during charging, and high specific gravity sulfuric acid tends to accumulate in the lower part. As a result, stratification occurs in which the sulfuric acid concentration of the electrolyte solution varies up and down, but when the charge amount is sufficient (overcharge), the electrolyte solution is stirred by the gas generated from the electrode plate at the end of charging, and stratification is eliminated To do.
However, since the lead storage battery used in PSOC has a small amount of overcharge, it is difficult to eliminate the stratification of the electrolyte. In the lower part where the specific gravity of sulfuric acid is increased, the charge acceptability is lowered, and sulfation (accumulation of lead sulfate) proceeds in the lower part of the negative electrode plate. Further, since the charge / discharge reaction concentrates on the upper part of the electrode plate, the deterioration of the active material on the upper part of the positive electrode plate is promoted, and the life performance is lowered.

As a means for suppressing the stratification of the battery used in PSOC, there is known a method of increasing the resistance during movement of sulfate ions or water in order to delay the sedimentation rate of sulfate ions or the rising rate of water.
Patent Document 1 discloses a liquid lead-acid battery in which a separator formed in a thin film based on a plurality of vertical ribs extending vertically is interposed between a paste-type positive electrode plate and a negative electrode plate. Then, the base thickness T1 (mm) of the separator, the distance T2 (mm) between the electrode plates of the positive electrode plate and the negative electrode plate opposed via the separator, and the total thickness of the separator at the location where the vertical rib is formed A liquid lead-acid battery in which the length T3 (mm) and the interval W (mm) between the vertical ribs satisfy the relationship represented by the following formulas (1) and (2).
1.5 ≦ (T2−T1) × W ≦ 3.5 Formula (1)
0.8 ≦ T3 / T2 ≦ 1.1 Expression (2) ”(Claim 1) is described.

It is also known to form vertical ribs having different heights on the separator.
Patent Document 2 states that “on the outer surface of the bag-like separator, a first longitudinal direction that is substantially orthogonal to the width direction is formed in a large part of the central portion in the width direction when the width between the both side edges is defined as the width direction. A plurality of ribs are arranged in parallel to each other, on both sides of the outer surface of the bag-like separator and in the vicinity of the portion facing the end of the positive electrode plate and in the vicinity thereof, parallel to the first vertical ribs A plurality of second vertical ribs are arranged in parallel to each other, and an interval between the two adjacent second vertical ribs is shorter than an interval between the two adjacent first vertical ribs, When the protruding height of the second vertical rib from the surface of the bag-shaped separator is T2, and the protruding height of the first vertical rib from the surface of the bag-shaped separator is T1, T2 <T1, and T2 ≧ 0.2 mm or more, and the positive electrode plate includes an expanded lattice having no vertical frame bone, End of the positive electrode plate with no frame bone, the lead-acid battery facing the second longitudinal rib. "Discloses the invention of (claim 1).
And, as batteries A1 and B1 of specific comparative examples, those having a T2 / T1 ratio of 1.11 are listed in Table 1.

  Patent Document 3 states that “a negative electrode plate is housed in a bag-shaped separator having a large number of ribs projecting on the surface, and a positive electrode plate is stacked in contact with the rib of the bag-shaped separator to form an electrode plate group. In the lead storage battery accommodated in the battery case, the height of the rib provided in the portion located outside the width dimension of the negative electrode plate of the bag-shaped separator is located inside the width dimension of the negative electrode plate. The lead storage battery is higher than the height of each rib. "(Claim 1) is described.

Japanese Patent Laid-Open No. 2015-22921 JP 2010-140772 A JP 2003-92098 A

  The lead storage battery used in PSOC is likely to be in an overdischarged state, and sulfuric acid is consumed by the discharge reaction near the surface of the electrode plate, and the specific gravity of the electrolyte is low. In the low specific gravity electrolyte, the amount of lead ions increases, and the lead ions are reduced and deposited at the negative electrode during charging to grow dendrites, and the permeation short circuit where lead penetrates into the separator is accelerated. However, it has not been completely clarified whether the permeation short circuit occurs uniformly in the entire electrode plate or easily occurs in a specific region.

  On the other hand, strap formation by a COS method may be performed as a manufacturing method of a lead storage battery. In the COS method, molten lead in which lead or a lead alloy is melted is poured into the concave portion of the mold in which a concave portion having the same shape as the strap is engraved, and the tip of the ear of the electrode plate of the same polarity is poured into the molten lead in the molten lead After dipping and melting the ear with the heat of the molten lead, it is cooled and solidified to form a strap integrated with the ear.

In order to ensure the welding of the ear and the strap, a gap through which the molten lead flows outside the ear of the electrode plate at both ends of the same polarity is necessary. Accordingly, for example, in the case of the negative strap shown in FIG. 1, the length A between the outer ends of the ears at both ends in contact with the lower surface of the strap (hereinafter referred to as “ear group length A immediately below the strap” or “ear group length A”). Simply referred to as “length A” or “A”) is shorter than the length of the concave portion of the mold, that is, the length of the strap.
In the COS method, when the shape of the mold is not changed, the negative electrode plate connected to the negative electrode strap is increased when the thickness dimension of the electrode plate group in the stacking direction is considerably increased by increasing the number of electrode plates. Length B between the outer ends in the stacking direction of the upper frame in the current collector of the negative electrode plate located at both ends (hereinafter referred to as “upper electrode plate group length B”, simply “length B” or “B Is also longer than the ear group length A immediately below the strap. The upper electrode plate group length B is a value at the center in the width direction of the electrode plate. The length between the outer ends of the ears at both ends in contact with the lower surface of the positive strap and the length between the outer ends in the stacking direction of the upper frame of the current collector of the positive plate located at both ends of the positive plates connected to the positive strap The same relationship applies to.

  The present inventor has found that the above-described penetration short circuit occurs frequently at the upper part of the electrode plate group, particularly at the center in the width direction of the electrode plate. Furthermore, as a result of examining the magnitude relationship between the ear group length A and the upper electrode plate group length B, it was found that the occurrence of an osmotic short circuit becomes significant when A <B. In addition to the above, the present inventor has also found that when A <B, the permeation-resistant short-circuit performance is lowered, but the low-temperature high-rate discharge characteristics are improved. When A ≧ B, the osmotic short circuit is suppressed as compared to the case of A <B. However, in order to satisfy A ≧ B, it is necessary to increase the size of the strap as compared with the case where A <B. As a result, for example, the material cost increases, the mold needs to be updated, or It may be difficult to store in a battery case having a predetermined size as defined in JIS D5301.

  The invention described in Patent Document 1 specifies the relationship between the base thickness of the separator, the total thickness, the rib interval, and the electrode plate distance, thereby finely dividing the space between the positive electrode plate and the separator, By providing an appropriate resistance to sedimentation and water rise, the stratification of batteries used in PSOC is suppressed (paragraphs [0002] to [0007]). However, it does not consider permeation resistance short circuit performance.

In the inventions described in Patent Documents 2 and 3, by adjusting the interval between the positive electrode plate and the separator so that the rib height in the width direction of the separator differs between the end portion and the central portion, The purpose is to prevent the active material from dropping or the short circuit due to the breakage of the separator, and is not intended to improve the permeation resistance short circuit performance. Note that a short circuit due to breakage of the separator and an infiltration short circuit are completely different phenomena.
In Patent Document 3, a rib having a high protruding height at the end in the width direction of the separator supports the end of the positive electrode plate only when the positive electrode plate extends in the width direction. That is, the rib does not face the end of the positive electrode plate when the positive electrode plate does not extend in the width direction. In addition, the invention described in Patent Document 3 is not intended to improve permeation resistance short circuit performance.

  An object of the present invention is to provide a lead-acid battery in which the ear group length A on the lower surface of the strap is smaller than the upper electrode plate group length B and the permeation-resistant short-circuit performance is improved.

In order to solve the above-mentioned problems, the present invention has the following means.
This first invention is a lead storage battery comprising an electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator, an electrolyte, and a battery case containing the electrode plate group,
The upper frame bone in the pole plate located at both ends of the pole plates connected to the at least one strap, in which the length A between the outer ends of the ears at both ends immediately below at least one of the positive strap and the negative strap is Smaller than the length B between the outer ends in the stacking direction of the parts,
The separator has a plurality of ribs on at least one of a surface facing the positive electrode plate and a surface facing the negative electrode plate,
The rib has, in at least one surface of the separator, a height (T ₁ ) in the protruding direction of the first rib that faces the central portion in the width direction of the positive electrode plate or the central portion in the width direction of the negative electrode plate. The height (T ₂ ) in the protruding direction of the second rib that faces the end in the width direction of the positive electrode plate or the end in the width direction of the negative electrode plate is lower.

According to the second invention, in the first invention, a ratio T ₂ / T ₁ between a height (T ₁ ) of the first rib in the protruding direction and a height (T ₂ ) of the second rib in the protruding direction. Satisfies the relational expression of T ₂ / T ₁ ≧ 1.2.

  The third invention is the electrode plate according to the first or second invention, wherein the thickness of the electrode plate group in the width direction center portion of the positive electrode plate is equal to the thickness of the electrode plate in the width direction end portion of the positive electrode plate. It is more than the thickness of a group electrode plate lamination direction.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the lead storage battery is a lead storage battery for an idling stop vehicle.

According to the first invention, it is possible to provide a lead-acid battery having improved permeation short-circuit performance.
According to the second invention, it is possible to provide a lead storage battery having further improved permeation resistance short circuit performance.
According to the third aspect of the present invention, it is possible to provide a lead storage battery in which the permeation resistance short circuit performance is significantly improved.
According to the fourth aspect of the present invention, an effect of suppressing an osmotic short circuit, an effect of miniaturizing a strap, and a design capable of accommodating an electrode group suitable for idling stop vehicle use in a limited space in a battery case are possible. By simultaneously obtaining the effect, it is possible to provide a lead storage battery particularly suitable for idling stop.

Explanatory drawing of ear group length A and upper electrode plate group length B just below the strap Top view of separator according to the present invention Illustration of cycle pattern of PSOC life test Graph showing relationship between T ₂ / T ₁ and penetration short-circuit occurrence rate Graph showing the relationship between T ₂ / T ₁ and PSOC life

In the lead storage battery of the present invention, the ear group length A and the upper electrode plate group length B immediately below the strap are A <B, and the separator is at least one of the surface facing the positive electrode plate and the surface facing the negative electrode plate. A plurality of ribs, and the ribs extend in a protruding direction of the first rib facing the central portion in the width direction of the positive electrode plate or the central portion in the width direction of the negative electrode plate on at least one surface of the separator. The height (T ₁ ) of the second rib is lower than the height (T ₂ ) in the protruding direction of the second rib facing the end in the width direction of the positive electrode plate or the end in the width direction of the negative electrode plate. And At least one of the negative electrode strap and the negative electrode plate or at least one of the positive electrode strap and the positive electrode plate may satisfy A <B, but it is preferable that A <B holds for both the negative electrode strap and the negative electrode plate and both of the positive electrode strap and the positive electrode plate.

Embodiments of the present invention are shown below. In carrying out the present invention, the embodiments can be changed as appropriate according to common sense of those skilled in the art and disclosure of prior art. Hereinafter, the negative electrode material is referred to as a negative electrode active material, and the positive electrode material is referred to as a positive electrode active material. The negative electrode plate is composed of a negative electrode current collector and a negative electrode active material (negative electrode material), the positive electrode plate is composed of a positive electrode current collector and a positive electrode active material (positive electrode material), and solid components other than the current collector are It belongs to the active material (electrode material). The current collector includes a lattice portion filled with an active material, an upper frame bone portion connected to an edge of the lattice portion, a lower frame bone portion, and ears protruding from the upper frame bone portion, and further, a lateral frame bone portion, Some have feet protruding from the lower frame bone.
In the present invention, the upper part of the electrode plate group (laminated body) refers to the upper part up to 50% from the top and the lower part up to 50% from the bottom, based on the height of the lattice part in the current collector. The end portion in the width direction of the electrode plate refers to a portion from the both ends in the width direction of the electrode plate to 20% of the electrode plate width with reference to the width of the electrode plate. The width direction center part of an electrode plate means the part except the width direction edge part of the electrode plate in the electrode plate. The width direction of the electrode plate is as shown in FIG.

  The lead storage battery according to the present invention includes, for example, an electrode plate group including a negative electrode plate using lead as an active material, a positive electrode plate using lead dioxide as an active material, and a separator interposed between these electrode plates. The electrode plate group is housed in a battery case and immersed in a flowable electrolytic solution mainly composed of dilute sulfuric acid.

  The negative electrode plate and the positive electrode plate are formed by filling a grid portion of a current collector made of a Pb—Sb alloy, a Pb—Ca alloy, a Pb—Ca—Sn alloy, or the like with a paste-like active material. It is. Each of these constituent members can be appropriately selected from known ones according to the purpose and use.

  What is generally used as a separator of a liquid lead acid battery can be used for a separator. For example, a sheet mainly composed of polyolefin having fine pores, or a mat mainly composed of resin or glass fibers can be used. In particular, from the viewpoint of handleability and cost, it is preferable to use a sheet mainly composed of polyethylene having fine holes. The separator may have a flat plate shape, but is preferably a bag shape that accommodates either the positive electrode plate or the negative electrode plate in order to prevent the active material from falling off. Since the positive electrode plate has a large corrosion elongation, it is more preferable that the positive electrode plate has a bag shape for housing the negative electrode plate.

When the negative electrode plate is stored in the bag-shaped separator, as shown in a top view of FIG. 2, the separator has a flat plate-like portion (hereinafter referred to as the following) on at least one of the surface facing the positive electrode plate and the surface facing the negative electrode plate. A plurality of ribs protruding from a base portion), and of the ribs, a first portion facing a central portion in the width direction of the positive electrode plate or a central portion in the width direction of the negative electrode plate. The height (T ₁ ) of the rib in the protruding direction is the height (T ₂ ) of the second rib facing the widthwise end of the positive electrode plate or the widthwise end of the negative electrode plate. Is lower. The height (T ₁ ) in the protruding direction of the first rib and the height (T ₂ ) in the protruding direction of the second rib are the heights from the surface of the protruding base portion. The first rib facing the central portion in the width direction of the electrode plate is preferably in a region facing a range excluding a portion within 20% of the electrode plate width from both ends in the width direction of the electrode plate. The second rib facing the end in the width direction of the electrode plate preferably includes the end in the width direction of the electrode plate and is in a region facing a portion within 20% from the end. In addition, it does not exclude that the separator has ribs on the other side of the one side.
When a rib is provided on the surface facing the positive electrode plate, oxidation and damage of the separator due to contact between the separator base and the positive electrode plate can be prevented. Therefore, it is preferable to have a rib at least on the surface facing the positive electrode plate.
Surface facing the positive electrode plate, the case where a plurality of ribs on both sides of opposed surfaces and a negative electrode plate, may be a T _{1 <T 2} in the ribs on one side, in the ribs of both faces, T 1 _{<T 2} may be sufficient.
The total thickness of the base and ribs is called the total separator thickness. When ribs are provided on one side, the total separator thickness is the sum of the base thickness and the rib height of the highest rib. When ribs are provided on both sides, the total separator thickness is the same as the base thickness. This is the total value of the rib heights of the highest ribs on the surface. The total separator thickness is preferably about 0.3 to 1.0 mm, T ₁ is about 0.1 to 0.8 mm, T ₂ is about 0.15 to 0.9 mm, and T ₁ is less than T ₂ by about 0.2 mm. It is preferably about 1 mm to 0.5 mm smaller.
The direction in which the first rib and the second rib extend is arbitrary such as the vertical direction, the horizontal direction, and the diagonal direction. The shape of the first rib and the second rib is arbitrary, such as a linear protrusion, a shape in which point-like protrusions are arranged, and a linear protrusion is preferable. Moreover, you may have the 3rd rib whose height to a protrusion direction is lower than a 2nd rib in the part facing the width direction edge part of an electrode plate. In addition, the second rib may not have T ₁ <T ₂ over the entire length, and may have a portion that is partially low in the protruding direction. T ₁ <T ₂ may be T ₁ = 0 and T ₂ > 0, and does not have a rib (first rib) at a portion facing the central portion in the electrode plate width direction, and ends in the electrode plate width direction. Embodiments having ribs (second ribs) only in the part facing the part are also within the scope of the present invention.

The positive electrode plate and the negative electrode plate are laminated via the separator, and the electrode plates having the same polarity are joined together by welding by a COS method to form an integrated electrode plate group. . A portion formed by welding and integrating the ears of a plurality of electrode plates is a strap. In the lead storage battery of the present invention, the ear group length A immediately below at least one of the positive strap and the negative strap is smaller than the upper plate group length B of the electrode plate connected to the at least one strap. This length A is the length between the outer ends of the ears at both ends contacting the lower surface of the strap, as shown in FIG. As shown in FIG. 1, the length B is the length between the outer ends in the stacking direction of the upper frame bones of the current collectors of the electrode plates located at both ends of the electrode plates connected to the strap. The length A and the length B are dimensions after the electrode plate group is accommodated in the battery case and formed, and in a fully charged state. The measurement of this dimension can be performed in a state in which the electrode plate group is taken out of the battery case as long as the dimension of the electrode plate group in the stacking direction is substantially the same as the dimension when the battery case is stored.
In the present invention, the strap can be miniaturized by satisfying A <B. As a result, for example, the material cost is reduced, and it is not necessary to change the mold even if the size of the electrode plate group changes, or the electrode plate group that is longer in the stacking direction by filling more active materials Can be stored in a battery case having a predetermined size as defined in JIS D5301. In the present invention, the difference between the length A and the length B can be 1 mm or more, and is preferably 3 mm or more because the effects of the present invention are remarkable.

  In the strap, when a plurality of cell chambers exist in the battery case, an inter-cell connecting portion that connects adjacent battery cells and a pole column that is connected to a battery terminal are connected to each other. In the case where the battery case has a single cell structure, a pole column is connected to the strap. The strap, the inter-cell connection portion, and the pole column are formed using, for example, a Pb—Sn alloy or a Pb—Sb alloy.

  The electrode plate group is housed in a battery case made of a synthetic resin such as polypropylene, and sulfuric acid is added to form a battery case to produce a liquid lead-acid battery.

In the lead storage battery of the present invention, the permeation-resistant short-circuit performance is improved. The effect is that the height (T ₁ ) in the protruding direction of the first rib facing the central portion of the positive electrode plate in the width direction or the negative electrode plate in the width direction is the end portion of the positive electrode plate in the width direction or the negative electrode. By using a separator that is lower than the height (T ₂ ) in the protruding direction of the second rib facing the end in the width direction of the plate, the rib tip and rib of the first rib located at the center in the width direction of the electrode plate The separator surface located on the opposite side of the electrode is prevented from contacting the positive and negative electrode plates at the same time, and the path of the permeation short circuit can be cut off particularly in the center in the width direction between the electrode plates where the occurrence frequency of the permeation short circuit is high. Inferred.

Further, a separator made of a polyolefin-based synthetic resin or the like generally has a rib density higher than that of the base portion and a low porosity. Accordingly, since the electrolyte solution is insufficiently diffused at the contact portion between the rib and the electrode plate, the rib contact portion on the electrode plate surface is unlikely to contribute to the charge / discharge reaction.
According to the present invention, at the central portion in the width direction of the electrode plate, the rib tip of the first rib and the separator surface located on the opposite side of the rib are unlikely to contact the positive and negative electrode plates at the same time. Therefore, it is presumed that the diffusibility of the electrolytic solution is improved, so that stratification is suppressed and PSOC life performance is improved.

The effect of improving the permeation-resistant short-circuit performance is noticeable when the relationship between the length A and the length B is A <B. This is because in this case, the penetration short circuit occurs more frequently in the central part in the width direction of the electrode plate than in the case of A ≧ B, so that the penetration short circuit suppression effect by applying the present invention is clearly recognized. Because. In the case of A ≧ B, the frequency of occurrence of permeation short-circuits is low in the first place, and it has not been known so far that the frequency of occurrence is high especially in the central part of the electrode plate in the width direction, so that It is considered that a manufacturer or user who is not aware of this phenomenon will not recognize the phenomenon to such an extent that it can be distinguished from a penetration short circuit and a failure factor in other places.
In the present invention, it is possible to simultaneously obtain the effect of suppressing the penetration short circuit and reducing the size of the strap. The phenomenon that the occurrence frequency of the permeation short-circuit increases at the center of the electrode plate in the width direction among the upper parts of the electrode plate group by setting A <B is a phenomenon first found by the present inventors. Therefore, the height of the first rib located in the central portion in the width direction of the electrode plate in the projecting direction of the first plate is at the end in the width direction of the electrode plate. It can be said that the inventor has recognized for the first time that the use of a separator lower than the height in the projecting direction of the two ribs can simultaneously achieve the suppression of the penetration short circuit and the miniaturization of the strap.

In the above lead storage battery, the thickness of the electrode plate grouping direction of the electrode plate group at the center part in the electrode plate width direction is set to the electrode plate stacking direction of the electrode plate group at the end of the electrode plate width direction. It is preferable that the thickness be equal to or greater than.
When the strap is formed by the COS method, in general, the strap is formed in a state where the upper portion of the electrode plate group is clamped and fixed in order to prevent the position of the ears of each electrode plate group from shifting. When only the center part in the width direction of the electrode plate is clamped and fixed, the electrode plate group is particularly compressed at the center part in the width direction. In this case, in the lead storage battery in which T ₁ <T ₂ , the thickness in the electrode plate stacking direction of the electrode plate group in the center portion in the width direction is smaller than the thickness in the electrode plate stacking direction of the electrode plate group in the end portion in the width direction. Become. As a result, even in a lead storage battery with T ₁ <T ₂ , the separator tip located on the opposite end of the rib and the rib end of the first rib is likely to be in contact with the positive and negative electrode plates at the same time. It does not improve greatly.
When the entire width direction of the electrode plate is clamped and fixed, the electrode plate group is uniformly pressed in the width direction. Further, when only the end portion in the width direction of the electrode plate is clamped and fixed, the end portion in the width direction of the electrode plate group is particularly pressed. In these cases, in the lead storage battery in which T ₁ <T ₂ , the thickness in the electrode plate stacking direction of the electrode plate group in the center portion in the width direction is greater than or equal to the thickness in the electrode plate stacking direction in the electrode plate group in the width direction end portion Become. As a result, it is possible to more reliably prevent the separator tip located on the opposite side of the rib tip of the first rib from contacting the positive and negative electrode plates at the same time, so that the permeation short circuit performance is significantly improved. In addition, the thickness of the electrode plate grouping direction of the electrode plate group in the central portion in the width direction and the thickness of the electrode plate grouping direction of the electrode plate group in the end portion in the width direction are the values of the electrode plates at both ends of the electrode plate group in the electrode plate lamination direction. It is the thickness at the upper frame bone.

The present invention is preferably applied to a lead-acid battery for an idling stop vehicle. This is because a lead storage battery for an idling stop vehicle is used under PSOC conditions, and therefore has a higher probability of causing an osmotic short-circuit than batteries for other uses, and as a result, the significance of applying the present invention is great. .
Moreover, there is an effect obtained for the first time by applying the present invention to a lead-acid battery for an idling stop vehicle. Lead-acid batteries for idling stop vehicles require more active materials to achieve higher charge acceptance performance than those for non-idling stop vehicles. As a result, the dimension of the electrode plate group in the stacking direction ( For example, length B) tends to be large. When manufacturing a battery using such an electrode plate group, when A = B or A> B, the strap becomes large, so that it may be difficult to store in the battery case. is there. In particular, the battery of the type specified in JIS D5301 has an upper limit for the battery case size, and if the strap is too long, the battery may not be manufactured substantially. On the other hand, when A <B, since it is not necessary to enlarge the strap, the problem that it is difficult to store in the battery case is solved even when the dimension of the electrode plate group in the stacking direction is increased. It becomes possible. Therefore, in the present invention, on at least one surface, the height in the protruding direction of the first rib that opposes the central portion in the width direction of the electrode plate is the protrusion of the second rib that opposes the end portion in the width direction of the electrode plate. By providing a separator lower than the height in the direction and having a configuration of A <B, and further using it as a lead storage battery for an idling stop vehicle, the effect of suppressing the penetration short circuit, the effect of miniaturizing the strap, and idling The effect that the design which can accommodate the electrode group suitable for a stop car use in the space in the limited battery case is attained simultaneously. That is, only when the present invention is adopted, a penetration short circuit at the upper part of the electrode plate is suppressed, and a lead storage battery having a sufficient amount of active material can be manufactured as a lead storage battery for an idling stop vehicle.

  Specific examples and comparative examples of the present invention will be described below.

<Example 1: A3 battery>
(Positive electrode plate)
A positive electrode paste was prepared by mixing lead oxide by a ball mill method, synthetic resin fiber as a reinforcing material, water and sulfuric acid. This paste is filled in an expand-type grid-shaped positive electrode current collector made of an antimony-free Pb—Ca—Sn alloy, aging and drying are performed, and the paste is 100 mm wide, 110 mm high, and 1.6 mm thick. A chemical positive plate was prepared.

(Negative electrode plate)
A negative electrode paste was prepared by mixing lead oxide, scaly graphite, barium sulfate, lignin, synthetic resin fibers of reinforcing material, water and sulfuric acid by a ball mill method. This paste is filled in an expanded negative electrode lattice made of an antimony-free Pb—Ca—Sn alloy, and aged and dried to form an unformed negative electrode plate having a width of 100 mm, a height of 110 mm, and a thickness of 1.3 mm. Produced.

(Separator)
Using a synthetic resin sheet made of polyethylene as a base material, a bag-shaped separator having a longitudinal rib projecting from a base portion having a thickness of 0.2 mm on the outside was produced. This rib consists of a first rib and a second rib. The height of the first rib in the protruding direction (T ₁ ) is 0.5 mm, and the center portion in the width direction of the electrode plate excluding 15% (17 mm) from both ends of the electrode plate including both ends in the electrode plate width direction. Are provided at a position opposite to (a pitch between ribs of 10 mm). The second rib has a height (T ₂ ) in the protruding direction of 0.55 mm, and four ribs (ribs) at positions facing 15% (17 mm) from both ends of the electrode plate including both ends in the width direction of the electrode plate. The second rib is provided with a pitch of 3 mm between them. T ₁ and T ₂ are heights from the base surface on the side from which the ribs protrude.

(Battery configuration)
The negative electrode plate was housed in the bag-like separator, and a laminate was obtained by alternately laminating the seven negative electrode plates and the six positive electrode plates so that the negative electrode plates were on the outside. The separator has ribs only on the surface facing the positive electrode plate.
In the upper part of the laminate, with the center portion in the width direction of the electrode plates clamped, the ears of the positive electrodes and the ears of the negative electrodes are welded by the positive strap and the negative strap, respectively, by the COS method. An electrode plate group was prepared so as to be B. Example 1 which is a liquid lead acid battery in which this electrode plate group is housed in a polypropylene battery case, sulfuric acid is added, battery case formation is performed, and the electrolyte specific gravity after conversion is 1.285, 5 hR capacity is 30 Ah An A3 battery according to was manufactured. In the battery case, six electrode plate groups are connected in series. In addition, a battery for confirming the dimensions was separately prepared, and after the formation of the battery case, the battery was further fully charged, the lid was removed, and the length A and the length B on the positive electrode side and the negative electrode side were measured. Those in which A <B on both the positive electrode side and the negative electrode side are indicated as “A <B” in the following table. In the following table, “A = B” is used for the case where A = B on both the positive electrode side and the negative electrode side. Those in which A> B on both the positive electrode side and the negative electrode side are indicated as “A> B” in the following table.

<Comparative Example 3: A1 Battery, Comparative Example 4: A2 Battery>
The A1 and A2 batteries according to Comparative Examples 3 and 4 were manufactured in the same manner as in Example 1 except that separators having heights (T ₂ ) in the protruding direction of the second ribs of 0.25 mm and 0.5 mm, respectively, were used. Produced.

<Comparative Example 1: X Battery, Comparative Example 2: Y Battery>
An X battery and a Y battery were produced in the same manner as in Comparative Example 3, except that the strap size was increased and the electrode plate group was produced so that A> B or A = B.

<Example 2: A4 battery>
An A4 battery according to Example 2 was fabricated in the same manner as in Example 1 except that a separator having a height (T ₂ ) in the protruding direction of the second rib of 0.6 mm was used.

<Example 3: A7 battery, Example 4: A8 battery>
The A7 battery according to Example 3 is the same as Example 2 except that the electrode plate group is produced by the COS method with both ends in the width direction clamped at the upper part of the laminate. Thus, A8 batteries according to Example 4 were produced.

<Comparative Example 5: A5 battery, Comparative Example 6: A6 battery>
The A5 battery according to Comparative Example 5 and Comparative Example 6 are the same as Comparative Examples 3 and 4, respectively, except that the electrode plate group is produced by the COS method with both ends in the width direction clamped at the upper part of the laminate. An A6 battery according to was manufactured.

<Example 5: A9 battery, Example 6: A10 battery>
Example 1 and Example 1 were carried out except that a separator having a height (T ₁ ) in the protruding direction of the first rib of 0.25 mm and a height of the second rib (T ₂ ) of 0.5 mm was used. In the same manner as in Example 3, an A9 battery according to Example 5 and an A10 battery according to Example 6 were produced.

About said X, Y, A1-A10 battery, the following performance test was done after full charge.
(Low temperature high rate discharge performance test)
A fully charged liquid lead-acid battery was placed in a -15 ° C ± 1 ° C cooling chamber for 16 hours or more, then discharged at 150 A discharge current until the terminal voltage dropped to 6 V, and the discharge duration was recorded (JIS). D5301 (2006 revised version) high rate discharge characteristics test).

(PSOC life test)
The life test pattern shown in Table 1 and FIG. 3 was repeated in a constant temperature bath of 40 ° C., and the number of cycles until the terminal voltage reached 7.2 V was recorded. In addition, it is set as 1 cycle from the process 1 to the process 5.

(Penetration short circuit test)
The fully charged liquid lead acid battery was subjected to steps 1 to 5 shown in Table 2 in a constant temperature water bath at 25 ° C., and then the battery was disassembled to check for short circuits. About each Example and the comparative example, 20 lead storage batteries were tested, respectively, and the incidence rate of the penetration short circuit was evaluated.

Tables 3 and 4 below show the test results of the X, Y, and A1 to A10 batteries.
The “clamp position” is a clamp position in the width direction of the upper part of the electrode plate, and “low temperature HR” indicates a ratio in which the discharge time of the A1 battery in the low temperature high rate discharge performance test is 100%, and “PSOC life” "" Indicates a ratio where the cycle number of the A1 battery is 100%, and the permeation short-circuit occurrence rate is shown in increments of 5%.

From the results of Table 3, it can be seen that the A1 battery in which A <B is superior in the low-temperature high-rate discharge performance than the X battery in which A> B and the Y battery in which A = B. Therefore, it is important that A <B from the viewpoint of low-temperature high-rate discharge performance. On the other hand, it can be seen that the lead storage battery of A1 where A <B is inferior in permeation short-circuit performance than the lead storage battery of X where A> B and the lead storage battery of Y where A = B. These tendencies were the same when T ₁ = T ₂ .

All of the A1 to A10 batteries in Table 4 satisfy A <B. From the results of Table 4, A3, A4, and A7 to A10 batteries in which the height (T ₁ ) in the protruding direction of the first rib is lower than the height (T ₂ ) in the protruding direction of the second rib are T ₁ higher A1 battery than T _2, A5 cells, the same A2 cell _{T 1} is the _{T 2,} with respect to A6 battery, it was found that the excellent resistance to penetration short performance. This is presumably because in the battery of T ₂ > T ₁ , it is possible to prevent the front end of the first rib and the separator surface located on the opposite side of the rib from simultaneously contacting the positive and negative electrode plates. Further, it can be seen that the battery of T ₂ > T ₁ has better PSOC life performance than the battery of T ₂ ≦ T ₁ . This is because in the battery of T ₂ > T ₁ , the tip of the first rib and the separator surface located on the opposite side of the rib are less likely to contact the positive and negative electrode plates at the same time, so that the diffusibility of the electrolyte is improved and the electrolyte This is presumed to be due to the suppression of stratification.

On the other hand, the A1 battery is a battery in which the height in the protruding direction of the rib facing the central portion in the width direction of the electrode plate is higher than the height in the protruding direction of the rib facing the end portion in the width direction of the electrode plate. The penetration resistance short circuit performance is not improved as compared with the A2 battery in which the height in the protruding direction of the rib facing the central portion in the direction is equal to the height in the protruding direction of the rib facing the width direction end. In the A1 battery, it is considered that the rib tip of the second rib facing the end in the width direction of the electrode plate and the separator surface located on the opposite side of the rib can be prevented from simultaneously contacting the positive and negative electrode plates. However, since the improvement of the permeation-resistant short-circuit performance is not observed in the A1 battery, in order to improve the permeation-resistant short-circuit performance, the rib tip of the first rib facing the center in the width direction of the electrode plate and the opposite side of the rib It is inferred that it is important to prevent the separator surface located at the same time from contacting the positive and negative electrode plates simultaneously. The lead-acid battery has improved permeation-resistant short-circuit performance when the height in the protruding direction of the rib facing the center in the electrode plate width direction is lower than the height in the protruding direction of the rib facing the end in the electrode plate width direction. Is an unexpected effect.

Moreover, it can be seen from Table 4 and FIGS. 4 and 5 that the lead-acid storage battery with T ₂ / T ₁ ≧ 1.2 is particularly excellent in permeation resistance short circuit performance. This can more reliably prevent the rib tip of the first rib and the separator surface located on the opposite side of the rib from simultaneously contacting the positive and negative electrode plates, particularly in the range of T ₂ / T ₁ ≧ 1.2. It is assumed that it is possible. It is also found to be particularly excellent PSOC life performance in a lead-acid battery of _{T 2} / _{T 1} ≧ 1.2. This is particularly in the range of T ₂ / T ₁ ≧ 1.2, where the rib tip of the first rib and the separator surface located on the opposite side of the rib are less likely to contact the positive and negative electrode plates at the same time, and the diffusibility of the electrolyte is reduced. This is probably because the stratification of the electrolyte is further suppressed.

From Table 4, FIG. 4, and FIG. 5, when the A7 battery and A7 battery with the same rib structure of the separator but different clamp positions are compared, the A7 battery whose clamp position is the end in the width direction of the electrode plate is clamped. It can be seen that the permeation-resistant short-circuit performance is more excellent than the A3 battery whose position is the center in the width direction of the electrode plate. This is because, in the A7 battery in which the clamp position is the widthwise end of the electrode plate, the thickness of the electrode plate stacking direction at the center in the electrode plate width direction is the thickness of the electrode plate group at the electrode width direction end. It is presumed that the thickness in the electrode plate stacking direction is not less than that, and it is possible to more reliably prevent the front end of the first rib and the separator surface located on the opposite side of the rib from simultaneously contacting the positive and negative electrode plates. Also, it can be seen that the A7 battery is further superior to the A3 battery in PSOC life performance. This is probably because the stratification of the electrolyte is further suppressed. Similarly, in the comparison of the A4 battery and the A8 battery, and the A9 battery and the A10 battery, the A8 battery and the A10 battery in which the clamp position is the end portion in the width direction of the electrode plate were superior in the permeation short circuit resistance and the PSOC life performance. . On the other hand, in the battery of T ₂ ≦ T ₁ , the batteries (A5, A6) in which the clamp position is the width direction end of the electrode plate are compared with the batteries (A1, A2) in which the clamp position is the center part in the width direction of the electrode plate. Thus, there is no difference in permeation resistance short circuit performance.

In the examples, it was the most each performance better, the difference between T ₁ and T ₂ is large, the clamp position was A10 cell is an end.

  According to the present invention, in a battery in which the ear group length A and the upper electrode plate group length B immediately below the strap are A <B, the permeation-resistant short-circuit performance can be improved. Further, since the PSOC life performance can be improved, it is expected to be applied to IS storage lead storage batteries and the like that are frequently used in PSOC.

A Length of ear group just below the strap B Distance between upper plates located on both ends of the pole plates connected to the strap (length of upper plate group)

Claims (4)

A lead storage battery comprising an electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator, an electrolyte, and a battery case containing the electrode plate group,
The upper frame bone in the pole plate located at both ends of the pole plates connected to the at least one strap, in which the length A between the outer ends of the ears at both ends immediately below at least one of the positive strap and the negative strap is Smaller than the length B between the outer ends in the stacking direction of the parts,
The separator has a plurality of ribs on at least one of a surface facing the positive electrode plate and a surface facing the negative electrode plate,
The rib has, in at least one surface of the separator, a height (T ₁ ) in the protruding direction of the first rib that faces the central portion in the width direction of the positive electrode plate or the central portion in the width direction of the negative electrode plate. the lead-acid battery, characterized in that the lower positive electrode plate edge in the width direction or the height of the the second rib protruding direction of opposite to the end portion in the width direction of the negative electrode plate (T _2). The ratio _{T 2} / _{T 1} between the height of the projecting direction of said first rib _{(T 1)} to the height of the protruding direction of the second rib _{(T 2)} is of _{T 2} / _{T 1} ≧ 1.2 The lead acid battery according to claim 1, wherein the relational expression is satisfied.   The thickness in the electrode plate stacking direction of the electrode plate group in the center portion in the width direction of the positive electrode plate is equal to or greater than the thickness in the electrode plate stacking direction of the electrode plate group in the end portion in the width direction of the positive electrode plate. The lead acid battery according to claim 1 or 2. The lead acid battery according to any one of claims 1 to 3, wherein the lead acid battery is a lead acid battery for an idling stop vehicle.