JP6665465B2 - Lead storage battery - Google Patents

Description

  The present invention relates to a lead storage battery, and more particularly to a lead storage battery that suppresses osmotic short circuit.

The use of lead-acid batteries in an incomplete charge state (PSOC (Partial state of charge)) is 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 with electric power from the storage battery at the time of starting. Therefore, the storage battery is used in a state of insufficient charge. Not only for IS applications, but also in order to improve energy efficiency, the storage battery is often placed in an undercharged state because charging the storage battery is avoided and the power taken from the storage battery is increasing.

  In a battery with a small charge amount and a large discharge amount, consumption of sulfuric acid proceeds, and the specific gravity of the electrolytic solution is reduced. When the specific gravity decreases, the solubility of lead sulfate increases, and the amount of lead ions in the electrolyte increases. The lead ions are reduced and precipitated at the negative electrode during charging, and lead penetrates into the separator.

Patent Literature 1 discloses an "object of providing a lead-acid battery that maintains an appropriate group pressure with respect to an electrode plate and exhibits high performance" (page 1). In a lead-acid battery including an electrode plate group in which a separator having elasticity and flexibility is interposed, a plurality of vertical ribs are provided on the positive electrode facing surface and the negative electrode facing surface of the separator so as to be displaced from each other. The invention of "lead-acid battery characterized by the following claims" is described.
This rib is described as "not only a gap is formed on the surface of the electrode plate for securing the electrolyte, but also gas outflow can be improved" (page 4).

Patent Literature 2 states that “the diffusion power of the electrolyte solution in the electrode group is improved to prevent the negative active material from being changed to highly crystalline lead sulfate that does not contribute to charge and discharge by the concentrated sulfuric acid. It is an object of the present invention to provide a lead-acid battery having excellent discharge cycle life characteristics (paragraph [0016]), wherein a positive electrode plate and a negative electrode plate using a lattice body made of a lead alloy not containing antimony are used. An electrode plate group comprising a synthetic resin bag-shaped separator, and the bag-shaped separator is provided with a plurality of vertically parallel ribs back to back on both front and back surfaces thereof, and a negative electrode plate therein. The height of the rib on the back surface that is positioned and in contact with the negative electrode plate is higher than the height of the rib on the front surface. "(Claim 1).
According to the present invention, "supply of an electrolytic solution between an electrode plate, especially a negative electrode plate, and a separator, and diffusion are improved, and the active material is prevented from being changed to lead sulfate which does not contribute to charge / discharge by concentrated sulfuric acid. To improve the charge / discharge cycle life of the battery "(paragraph [0037]).

Patent Literature 3 discloses a liquid lead-acid battery that is “suitable for use in a partially charged state (PSOC), and particularly suitable for use in idling stop vehicles” (paragraph [0029]). Such invention is disclosed, `` By forming vertical ribs on the separator and finely dividing the space formed between the positive electrode plate and the separator, the resistance at the time of movement of sulfate ions and water contained in the electrolyte solution is reduced. It has been found that the present invention can be effectively increased, and the present invention has been completed. "(Paragraph [0007]), and according to the present invention," the stratification of the electrolytic solution is favorably suppressed, Lifetime performance can be improved "(paragraph [0015]).
Furthermore, a battery obtained by applying different separators to a Q-55 type lead-acid storage battery for an idling stop vehicle specified in the Battery Association of Japan standard SBA S 0101: 2006 is used as a test battery, and SBA S 0101: An idling stop life test was performed in accordance with 2006. "

Japanese Utility Model Application No. 57-17062 JP-A-7-105929 JP-A-2015-22921

  As a method of manufacturing a lead storage battery, there is a case where a strap is formed by a COS method. In the COS method, molten lead or lead alloy is poured into the concave portion of a mold in which a concave portion having the same shape as the strap is engraved, and the tip of the same polarity electrode plate ear is immersed in the molten lead. Then, the ear is melted by the heat of the molten lead, and then cooled and solidified to be integrated with the ear.

In order to ensure the welding of the ear and the strap in the COS method, it is necessary to provide a gap through which molten lead flows outside the ears at both ends of the same electrode plate. The length A between the outer ends of the ears at both ends in contact with (hereinafter, referred to as "ear group length A immediately below the strap" or "ear group length A", and also simply as "length A" or "A"). , Less than the length of the recess in the mold, ie the length of the strap.
Further, in the COS method, when the shape of the mold is not changed, and when the thickness of the electrode group in the stacking direction becomes considerably long by increasing the thickness of the electrode plate, the electrode group shown in FIG. The dimension B in the stacking direction at the upper part, more precisely, the length B between the outer ends in the stacking direction of the upper frame bones in the current collectors of the electrode plates located at both ends of the electrode plates connected to the strap (hereinafter, referred to as The “upper plate group length B”, simply referred to as “length B” or “B”) is longer than the ear group length A immediately below the strap. The length of the ear group immediately below the positive electrode strap is A ', and the length between the outer ends in the stacking direction of the upper frame bones of the electrode plates located at both ends of the positive electrodes connected to the positive electrode strap (upper electrode group length B') Then, A 'and B' have the same relationship (A 'and B' are not shown). Hereinafter, the magnitude relation between A and B and between A 'and B' will be described using A and B as representatives.

  The inventor of the present invention has found that the location where the above-mentioned osmotic short-circuit occurs frequently occurs in the upper part of the electrode group, especially near the upper end near the upper frame bone, and furthermore, the ear group length A and the upper electrode As a result of examining the magnitude relationship of the group length B, it was found that when A <B, the above phenomenon became significant. In addition to the above, the present inventor has also found that when A <B, the short-circuit resistance to permeation is reduced, but the high-temperature high-rate discharge characteristics are improved. When A ≧ B, the penetration short circuit is suppressed as compared with the case where 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 happen that it becomes difficult to store the battery pack in a battery container having a predetermined size as defined in JISD5301.

Each of the inventions described in Patent Documents 1 and 2 relates to a lead-acid battery in which a separator has a rib on a positive electrode facing surface and a rib on a negative electrode facing surface, and secures an appropriate group pressure and an electrolytic solution. It is intended to facilitate supply and diffusion of an electrolyte solution (Patent Document 2).
However, there is no description that the strap is formed by the COS method, and there is no suggestion as to the magnitude relationship between the ear group length A immediately below the strap and the upper electrode plate group length B. Further, there is no knowledge about low-temperature high-rate discharge performance or PSOC life performance.
Patent Literature 3 describes PSOC life performance, but does not describe forming a strap by the COS method. Further, it is only shown that the separator has a rib on the surface facing the positive electrode, and there is no knowledge about the short-circuit resistance and the low-temperature high-rate discharge performance.

  An object of the present invention is to improve the short circuit resistance to penetration short circuit in a lead-acid battery in which A <B.

The present invention has the following means in order to solve the above problems.
The first invention is a lead storage battery including an electrode group in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween, an electrolytic solution, and a battery case containing the electrode group,
The length A between the outer ends of the ears at both ends immediately below the negative electrode strap connecting the ears of the negative electrode plate, and the length A 'between the outer ends of the ears at both ends immediately below the positive electrode strap connecting the ears of the positive electrode plate are: The length B, B ′ between the outer end surfaces of the upper frame bones of the pole plates located at both ends of the pole plates connected to the straps,
The separator ribs in a region facing said negative electrode plate including a region facing the upper 50% or less of the area of the region and the negative electrode plate facing the positive electrode plate including an upper 50% or less of the area and facing region of the positive electrode plate A lead storage battery for an idling stop vehicle, comprising:
The upper part of the positive electrode plate and the upper part of the negative electrode plate are one end of the upper part of the positive electrode plate when the direction from the upper frame bone to the lower frame bone of the current collector of the positive electrode plate and the negative electrode plate is defined as the lower direction. And a region extending from one end of the upper part of the negative electrode plate to a predetermined distance in the lower direction. One end of the upper part of the positive electrode plate and one end of the upper part of the negative electrode plate are the upper ends of the upper frame members, and the predetermined distance is the shortest distance from the upper end of the upper frame members to the lower end of the lower frame members.

In the second aspect of the present invention, in the first aspect, the separator has a rib on one surface in a region facing the entire surface of the positive electrode plate or a region facing the entire negative electrode plate, and on the other surface, the positive electrode plate The ribs are provided only in the region facing the region of 50% or less of the upper portion of the negative electrode plate, or only in the region facing the region of 50% or less of the upper portion of the negative electrode plate.

The third invention is characterized in that, in the first invention or the second invention, the shape of the rib is a dot shape .

In the fourth invention, in any one of the first to third inventions , a difference between the length A and the length B and a difference between the length A ′ and the length B ′ are 1 mm or more. is there.

  The fifth invention is characterized in that in the first to fourth inventions, the separator is mainly composed of polyethylene.

  In the sixth invention, in the first to fifth inventions, the separator has a structure in which the rib is cut out in a region facing a part or all of a lower part of the electrode plate on a surface facing one of the electrode plates. It is characterized by being.

According to the first to sixth invention, penetration short-circuiting is suppressed, and it is possible to provide a lead storage battery for an idling stop vehicle provided with a sufficient PSOC life performance.

Explanatory drawing of ear group length A and upper electrode plate group length B just below the strap Cross-sectional view for explaining the positional relationship between the base and the rib of the separator Explanatory drawing of expandable current collector Illustration of casting type current collector Schematic diagram showing rib shapes that can be used in the present invention Explanatory drawing of the cycle pattern of the PSOC life test Graph showing the relationship between rib area and PSOC life

  The lead storage battery of the present invention has a rib group in a region where the separator faces the upper portion of the positive electrode plate and a region facing the negative electrode plate, and a lug length A on the lower surface of the negative electrode strap connecting the lugs of the negative electrode plate, and the positive electrode plate. The ear group length A 'on the lower surface of the positive electrode strap connecting the ears is determined by the distances B and B' between the electrode plates located at both ends of the electrode plates connected to the respective straps in the upper frame bone. It is characterized by being small.

  Hereinafter, embodiments of the present invention will be described. In practicing the present invention, the embodiments can be appropriately modified in accordance with the common knowledge of those skilled in the art and the disclosure of the 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 includes a negative electrode current collector and a negative electrode active material (negative electrode material). The positive electrode plate includes a positive electrode current collector and a positive electrode active material (positive electrode material), and solid components other than the current collector. Shall belong to the active material (electrode material).

  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 porous separator interposed between these electrode plates. The electrode group is housed in a battery case, and is immersed in a flowable electrolytic solution containing dilute sulfuric acid as a main component.

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

  In the case of the expandable type shown in FIG. 3, the current collector protrudes from a grid portion filled with the active material, an upper frame bone portion, a lower frame bone portion connected to an edge of the grid portion, and an upper frame bone portion. With ears In the case of the casting type shown in FIG. 4, a foot protruding from the horizontal frame bone and the lower frame bone is further provided.

The separator used in the present invention contains polyolefin as a main component, has fine pores, and is mainly composed of a flat sheet, and has a projection in contact with the positive electrode plate at an upper portion of one surface of the sheet. , On the other surface, a projection that contacts the upper part of the negative electrode plate. These projections are the ribs in the present invention. The rib of the conventional general separator is a line-shaped projection provided uniformly along the vertical direction of a surface facing the positive electrode plate in order to prevent the oxidation loss of the separator due to oxygen generated from the positive electrode plate (for example, The rib of the present invention is a protrusion formed in a region facing the upper part of the positive electrode plate or a region facing the upper part of the negative electrode plate.
In this specification, a rib formed in a region facing a positive electrode plate is referred to as a “positive electrode rib”. The rib formed in the region facing the negative electrode plate is called “negative electrode rib”.
The thickness of the flat portion of the separator (hereinafter referred to as “base” or “base portion”) is referred to as “base thickness”. The height of the rib including the “base thickness” at the position where the positive electrode rib is formed on the separator is referred to as “positive electrode rib height” or “rib height”. The height of the rib including the “base thickness” at the portion where the negative electrode rib is formed on the separator is referred to as “negative electrode rib height”.
The thickness of the separator at the location where the positive rib is formed or the location where the positive and negative ribs are formed is referred to as “total thickness of the separator” or “total thickness”.
A line-shaped rib (hereinafter, also referred to as a “line rib”), which is a continuous rib from one end to the other end of the separator, or a dot-shaped rib (hereinafter, also referred to as a “dot rib”). The ribs uniformly distributed from one end to the other end of the separator are called "all ribs".
It is a line-shaped rib that is continuous from the upper end of the separator for a predetermined distance in the lower direction, a rib that is intermittent from the upper end of the separator to the other end in the lower direction, or a dot-shaped rib. The ribs distributed including only the upper part of the separator are referred to as “partial ribs”.
In the present invention, since the total thickness of the separator is defined as described above, when viewed in a cross section of the separator (a cross section cut in a direction perpendicular to the vertical direction of the separator), as shown in FIG. In addition, there are overlapping portions in the positive electrode rib forming portion and the negative electrode rib forming portion.
As the polyolefin, for example, polyethylene can be used. The separator of the present invention may have a bag shape or a flat shape. In the case of a bag, any of the positive electrode plate and the negative electrode plate may be stored in the bag.

In the present invention, the rib provided on the separator has a function of preventing the base from contacting the surface of the electrode plate and a region in the vicinity thereof. In addition, the standard of the said vicinity is an area | region which is about 0.1 mm away from the surface of an electrode plate. The base thickness is preferably from 0.15 to 0.3 mm, more preferably about 0.25 mm.
In the separator used in the present invention, the total thickness of the base and the rib (separator total thickness) is preferably 0.5 mm or more and 1.0 mm or less, and according to Examples described later, more preferably 0.5 mm or more and 0.9 mm or less. . For the height and width of the rib on the positive electrode side, dimensions that can exert the above functions can be used.
The definition regarding the thickness of the separator used in the present invention will be described with reference to FIG. The thickness (base thickness) of the base portion of the separator is a dimension indicated by T. The total thickness of the separator, the dimensions shown in T _B if there are ribs on both sides, if there is a rib on only one side and dimensions shown in T _A. The height of the ribs is set to include the thickness of the base portion, for example, rib height protruding on the positive electrode side (cathode rib height), and dimensions shown in H _P.

  The shape of the rib used in the present invention may be a linear shape as shown in the left diagram of FIG. 5, or a dot shape as shown in the right diagram of FIG. The line-shaped rib may have a line width W as shown in the left diagram of FIG. 5 and may be a continuous rib extending from one end to the other end of the separator. It may be a continuous partial rib, or may be a continuous partial rib from one end of the upper part to the other end in the lower direction. The cross section of the linear rib can be rectangular or square or trapezoidal as shown in FIG. On the other hand, the dot-shaped ribs may be all ribs uniformly distributed from one end to the other end of the separator, or may be partial ribs including only the upper part. The dot-shaped rib has a structure in which a circular region having a predetermined diameter R protrudes as shown in the right diagram of FIG. 5, for example. The shape of the protruding portion may be a structure protruding in a columnar shape or a shape protruding in a hemispherical shape.

  In the present invention, the positive electrode plate and the negative electrode plate are stacked with a separator interposed therebetween, and the ears of the same electrode plate are connected and integrated. The portion formed by connecting the ears of the plurality of electrode plates is a strap, and in the case where a plurality of cell chambers are present in the battery case, the strap has an inter-cell connection portion connecting adjacent battery cells, and a strap of the battery. The poles to be connected to the terminals are provided in series. When the battery case has a single-cell structure, the pole is connected to the strap.

  The strap, the inter-cell connection portion, and the pole are formed using, for example, a Pb-Sn-based alloy, a Pb-Sb-based alloy, or the like.

  In the lead storage battery of the present invention, the lengths A and A ′ between the outer ends of the ears at both ends immediately below the negative electrode strap and the positive electrode strap are located at both ends of the electrode plates connected to the same-polarity strap. The length between the outer ends in the stacking direction of the upper frame bones of the plate is smaller than the lengths B and B ′, respectively. Hereinafter, the definitions of A and B and the definitions of A 'and B' will be described by using A and B as representatives. As shown in FIG. The length B is a length at a portion in contact with the lower surface of the strap, and the length B is, as shown in FIG. 1, a current collector of the electrode plate located at both ends of the electrode plate connected to the strap. This is the length between the outer ends of the upper frame bone in the stacking direction. The length A and the length B are dimensions after the electrode group is housed in the battery case and formed, and in a fully charged state. The measurement of this dimension can be performed in a state where the electrode group is taken out of the battery case, as long as the dimension of the electrode group in the stacking direction is substantially the same as the dimension when the battery case is stored.

  In the present invention, the size of the strap can be reduced by setting A <B and 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 group changes, or the electrode group becomes longer in the stacking direction by filling more active material. Can be accommodated in a battery case having a predetermined size as defined in JIS D5301. Further, in the present invention, the difference between the length A and the length B and the difference between the length A ′ and the length B ′ can be 1 mm or more, since the effect of the present invention is remarkable. It is preferable to set it to 3 mm or more.

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

The action and mechanism by which the present invention improves the resistance to penetration short circuit is presumed as follows.
In the lead storage battery used in the PSOC, an overdischarged state is apt to occur, and sulfuric acid is consumed by a discharge reaction near the surface of the electrode plate, which is a low specific gravity area of the electrolyte. If the ear group length A and the upper electrode group length B directly below the strap of the lead-acid battery adopting the COS method are A <B, the gap between the electrodes tends to be narrow at the upper part of the electrode plate. Alternatively, it cannot be separated from the low specific gravity region estimated to be formed near the surface. It is considered that since the concentration of lead ions is high in a low-density electrolyte, the lead ions are reduced and precipitated at the negative electrode during charging, dendrite grows, and penetration short circuit, in which lead penetrates into the base portion of the separator, is accelerated ( Comparative example described below: A1 battery).

The present invention relates to a battery of A <B and A'<B', separator, that have a rib in a region facing the upper portion of each of the negative electrode plate and a positive plate.

In the present invention, the effect of suppressing the occurrence of permeation short-circuit can be obtained by providing the separator with a rib in a region facing the upper part of each of the negative electrode plate and the positive electrode plate. This effect was achieved by providing a distance between the upper separator and the bipolar plate, and separating the separator from the low specific gravity region, which is presumed to be near the surface of the polar plate. This is presumed to be caused by the fact that the occurrence of penetration short circuit could be suppressed. Further, since the ribs are provided on both surfaces, the penetration short circuit is significantly suppressed as compared with the case where the ribs are provided on one surface. This is because when the base surface on the opposite side to the rib protruding direction comes into contact with the negative electrode plate, there is a property that the base surface is likely to be a starting point of a penetration short circuit. That is, when the ribs are arranged only on the positive electrode side as shown on the left side of FIG. 2, the surface of the positive electrode plate presses the ribs on the positive electrode side, so that the base portion on the opposite side of the ribs is pressed against the negative electrode. Becomes In such a situation, although the reason is not clear, a permeation short circuit occurs remarkably. Therefore, by arranging the ribs on both surfaces of the separator, such a situation can be avoided, and as a result, the penetration short circuit is largely suppressed.
Furthermore, by designing the rib height to decrease as the distance between the poles decreases, the effect of improving the low-temperature high-rate discharge performance and the PSOC life performance can be obtained. This effect is presumed to be caused by the fact that the reaction in the lower part is likely to occur and the sulfation is suppressed, and the reaction in the upper part is relaxed to suppress the deterioration of the active material in the upper part of the positive electrode plate.

  Further, in the present invention, the configuration of A <B and A ′ <B ′ provides an effect of suppressing the osmotic short circuit very specifically. Specifically, the effect is obtained that the osmotic short-circuit occurring near the upper portion of the electrode plate, particularly in the region near the upper frame bone is suppressed, and the osmotic short-circuit including the osmotic short-circuit in other regions is significantly suppressed. . This effect is recognized only when A <B and A ′ <B ′. Because, in the case of the configuration of A ≧ B and A ′ ≧ B ′, the phenomenon that the osmotic short circuit occurs selectively at the upper part of the electrode plate does not actually occur or does not occur to the extent that it can be clearly recognized. Because. In the case of A <B and A ′ <B ′, the osmotic short circuit in such a specific region occurs more frequently than the one occurring in other regions so as to be clearly distinguishable. Therefore, the significance of providing a rib in that region is greater than in the case where A = B and A ′ = B ′, or when A> B and A ′> B ′.

  Further, by adopting the configuration of A <B and A ′ <B ′, it is possible to obtain the effect that the strap can be miniaturized as described above, in addition to the effect of suppressing the penetration short circuit. Further, as will be described later, when A <B and A ′ <B ′, the low-temperature high-rate discharge performance is lower than when A = B and A ′ = B ′ or A> B and A ′> B ′. The effect of being excellent is also obtained.

  The present invention includes an embodiment in which a rib (partial rib) is provided only on an upper portion on a surface facing one electrode plate (see Examples: A2 to A7 batteries). According to the present invention, the PSOC life is superior to a battery having ribs on the entire surface facing both electrode plates (see Example: A8 battery). This is because the rib has a function of preventing ion movement in a portion abutting on the electrode plate, so that the rib has only one upper portion of one surface and has no rib at the lower portion, thereby reducing the reaction resistance of the lower portion. This is considered to further improve the uniformity of the reaction, suppress sulfation, and prevent deterioration and dropout of the positive electrode active material in the upper portion.

Further, the present invention includes an embodiment in which the ratio of the presence of the partial rib is set to 50% or less of the upper part of the electrode group (see Examples A2 to A6 batteries). For the same reason as described above, it is presumed that the PSOC life performance can be further improved by reducing the rib region where the reaction resistance increases.
It is preferable that a rib is provided only in a region facing the region of 30% or less of the upper part of the electrode plate.

  The present invention includes embodiments in which the ribs are dot-shaped (Examples described below: B1 to B3 batteries). Dot ribs can maintain the distance from the electrode plate with a smaller total area than line ribs, so it is possible to further suppress the increase in reaction resistance, and to use the hemispherical rib side surfaces as liquid or gas passages. Thus, the diffusibility of the liquid or gas is improved, and the stratification can be further suppressed, so that it is presumed that the PSOC life performance and the low-temperature high-rate discharge performance can be improved.

  Further, the present invention includes an embodiment in which a rib is cut out in a region facing a part or all of a lower part of the electrode plate on a surface facing one of the electrode plates. For example, when the rib is a linear rib, it is preferable that at least one of the ribs has a structure in which the rib is cut out in a region facing part or all of the lower part of the electrode plate. The notched structure means that there is no protruding portion from the base portion or that the rib is lower than the height of the upper rib. With the above-described configuration, the PSOC life is improved as compared with the structure in which the notch is not provided. This is because the rib has a function of preventing ion movement in a portion abutting on the electrode plate, so that the rib has only one upper portion of one surface and has no rib at the lower portion, thereby reducing the reaction resistance of the lower portion. This is considered to further improve the uniformity of the reaction, suppress sulfation, and prevent deterioration and dropout of the positive electrode active material in the upper portion. Here, the “lower portion” means a region from the lower end of the electrode plate to a predetermined height, and this predetermined height can be 50% or more of the height of the electrode plate, and a higher effect can be obtained. For this reason, the height is preferably set to 70% or more of the height of the electrode plate. The lower end of the electrode plate is the lower end of the lower frame bone, and the height of the electrode plate is the shortest distance from the lower end of the lower frame bone to the upper end of the upper frame bone.

The present invention is preferably applied to a lead storage 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 occurrence of a penetration short circuit as compared with batteries for other uses, and as a result, the application of the present invention is significant. .
Further, there is an effect obtained only by applying the present invention to a lead storage 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, and as a result, the dimensions of the electrode group in the stacking direction ( For example, length B) tends to be large. When manufacturing a battery using such an electrode group, when A = B and A ′ = B ′ or when A> B and A ′> B ′, the strap becomes large. It may be difficult to store in a battery case. In particular, for batteries of the type specified in JIS D 5301, the upper limit is set for the battery case size, so that if the strap is too long, it may be impossible to substantially manufacture the battery. On the other hand, when A <B and A ′ <B ′, it is not necessary to increase the size of the strap. Can be solved. Therefore, in the present invention, ribs are provided on both surfaces of the separator, and the ribs are arranged in a region facing the upper part of the electrode plate. By using as a lead storage battery, the effect of suppressing penetration short circuit at the upper part of the electrode plate, the effect of reducing the size of the strap, and the electrode group suitable for idling stop car use, the space inside the battery case with the upper limit specified by the standard And the effect of enabling a design that can be accommodated in a vehicle. That is, only by adopting the present invention, it is possible to manufacture a lead storage battery for an idling stop vehicle, which suppresses the osmotic short circuit in the upper part of the electrode plate and has the life performance under sufficient PSOC conditions.

Hereinafter, specific examples, comparative examples, and conventional examples of the present invention will be described.
(Positive electrode active material)
A positive electrode paste was prepared by mixing lead oxide by a ball mill method, a synthetic resin fiber as a reinforcing material, water and sulfuric acid. This paste is filled into an expanded-type grid-like positive electrode current collector made of an antimony-free Pb-Ca-Sn-based alloy, aged and dried to obtain a 100 mm-wide, 110 mm-high, 1.6 mm-thick uncollected paste. A chemical positive electrode plate was produced.

(Negative electrode active material)
A negative electrode paste was prepared by mixing lead oxide, flaky graphite, barium sulfate, lignin, synthetic resin fibers of a reinforcing material, water and sulfuric acid by a ball mill method. This paste is filled into an expandable negative grid made of an antimony-free Pb-Ca-Sn-based alloy, aged and dried to form an unformed negative plate having a width of 100 mm, a height of 110 mm and a thickness of 1.3 m. Produced. The amount of the mixture of flaky graphite, barium sulfate, lignin and synthetic resin fiber was 2 mass%, 0.6 mass%, 0.2 mass% and 0.1 mass%, respectively, when measured after formation and in a fully charged state. Adjusted to be.

(Separator)
A bag-shaped separator made of a synthetic resin based on polyethylene and having ribs described later was used. The total thickness of the separator is constant at 0.70 mm for all of the following batteries.

(Battery configuration)
The negative electrode plate was housed in the bag-shaped separator, and the seven negative electrode plates and the six positive electrode plates were alternately laminated such that the negative electrode plate was on the outside.
The ears of the positive electrode plates and the ears of the negative electrode plates are welded with a positive electrode strap and a negative electrode strap by a COS method, respectively, to produce an electrode group. The electrode group is housed in a polypropylene battery case, Was added, and a battery case formation was performed to produce a liquid lead storage battery having a specific gravity of 1.285 for the electrolytic solution after the formation and a capacity of 30 Ah for 5 hR. In the battery case, six electrode plates are connected in series. In addition, a battery for checking the dimensions is separately prepared, and after the battery case formation, the battery is further fully charged, the lids are removed, and the strap group lengths A and A 'on the positive electrode side and the negative electrode side, and the upper electrode plate group length B And B ′ were measured. Those in which A <B and A ′ <B ′ are indicated as “A <B” in the following table. Those in which A = B and A ′ = B ′ are described as “A = B” in the following table. Those in which A> B and A ′> B ′ are described as “A> B” in the following table.

<Comparative example: A1 battery>
The separator shown in the conventional example of FIG. 2 does not have a negative electrode rib, has a positive electrode rib in a region facing the entire positive electrode plate, has a base thickness T of 0.25 mm, and has a rib height (positive electrode rib height) H. There using the separator of 0.70mm equal to the total thickness T _a, was prepared ears group length immediately below the strap a, A'upper electrode plate group length each B, and A1 cell according to B'smaller Comparative example 1.
The ribs in the A1 to A9 batteries are all line ribs as shown in the left diagram of FIG. The line width W was 1 mm. The distance between the line ribs was 9 mm. Since the magnitude relation between A and B and between A 'and B' is the same, the relation between A and B will be described below as a representative.

<Conventional example 1: X battery>
Using the same separator as in Comparative Example 1, an X battery according to Conventional Example 1 was manufactured in which the ear group length A immediately below the strap was larger than the upper electrode group length B.

<Conventional example 2: Y battery>
Using the same separator as in Comparative Example 1, a Y battery according to Conventional Example 2 was manufactured in which the ear group length A immediately below the strap was the same as the upper electrode group length B, respectively.

(Low temperature high rate discharge performance test)
After the fully charged A1, X, and Y batteries were placed in a cooling room at -15 ° C. ± 1 ° C. for 16 hours or more, the discharge time until the terminal voltage dropped to 6V at a discharge current of 150 A was recorded. (Based on JIS D5301 high rate discharge characteristics test).

(Permeation short circuit test)
In addition to the low-temperature high-rate discharge performance test, a new liquid-type lead-acid battery was placed in a constant temperature water bath at 25 ° C., and after performing steps 1 to 5 shown in Table 1, the battery was disassembled to determine whether there was a short circuit. Examined. For each of the examples and comparative examples, 20 lead storage batteries were tested, and the occurrence rate of penetration short circuit was evaluated.

  Table 2 below shows the results for the A1, X, and Y batteries.

According to the above results, the occurrence rate of the penetration short circuit in the conventional X and Y batteries in which A> B and A = B is considerably smaller than in the case where A <B. This means that only when A <B, the problem of occurrence of a penetration short circuit is remarkably recognized. In addition, as a result of the observation, in most cases, the osmotic short circuit in the case of A <B occurred near the upper part of the electrode plate, particularly near the upper frame bone. It was not clearly observed that there were many cases occurring near the frame bone.
It was also found that the A1 battery in which A <B had low-temperature and high-rate discharge performance equal to or higher than that of the X and Y batteries.

<Example: A2 battery>
Instead of the A1 cell separator shown in FIG. 2, base thickness T is 0.25 mm, the positive electrode rib height _{H P} is 0.50 mm, the anode rib height _{H L} has a rib 0.45 mm, the total thickness T _B is a 0.70 mm, has only the region facing the upper 20% of the area of the grating portion of the negative electrode plate and the negative electrode ribs, except for using the separator having a region facing the cathode ribs positive electrode plate entire surface, An A2 battery according to the example was manufactured in the same manner as in the comparative example 1.

<Example: A3-A8 batteries>
Except for using a separator having a negative electrode rib only in a region facing the upper 30%, 50%, and 70% regions of the negative electrode plate or a region facing the entire negative electrode plate and a positive electrode rib in a region facing the entire positive electrode plate. A3, A5, A7, and A8 batteries according to the examples were manufactured in the same manner as the A2 battery.
The same procedure as in Example A2 was carried out, except that a separator having a positive electrode rib only in a region facing the upper 30% and 50% regions of the positive electrode plate and a negative electrode rib in a region facing the entire negative electrode plate was used. A4 and A6 batteries according to the examples were produced.

<Comparative Example 2: A9 battery>
An A9 battery according to a comparative example was manufactured in the same manner as the A2 battery except that a separator having a negative electrode rib only in a region facing the lower 50% region of the negative electrode plate and a positive electrode rib in a region facing the entire positive electrode plate was used. Produced.

<Example: B1 to B3 batteries>
A2, A3, and A5 batteries were operated in the same manner as the A2 battery except that the negative electrode rib of the separator used in the batteries was changed to a hemispherical dot rib (circle diameter R was 1 mm) as shown in the right diagram of FIG. B1 to B3 batteries according to the examples were produced.

The above-mentioned A1 to A9 and B1 to B3 batteries were subjected to the above-described low-temperature high-rate discharge performance test and the penetration short-circuit test, and further to the following PSOC life test.
(PSOC life test)
The life test pattern shown in Table 3 and FIG. 6 was repeated in a constant temperature bath at 40 ° C., and the number of cycles until the terminal voltage reached 7.2 V was recorded. The number of cycles is defined as one cycle of performing steps 1 to 5 once.

Table 4 below shows the test results of the lead storage batteries A1 to A9 and B1 to B3, and FIG. 7 shows the relationship between the upper rib area (electrode plate area ratio) and the PSOC life.
The “electrode plate area ratio” indicates the area ratio of the region where the ribs face to 100% of the area of the grid portion of the electrode plate, and the “PSOC life” indicates the ratio when the number of cycles of the A1 battery is 100%. The "low-temperature HR performance" indicates a ratio when the discharge time of the A1 battery is set to 100%, and the penetration short-circuit occurrence rate is indicated in increments of 5%.

  From the results shown in Table 4, the A2 to A8 batteries using the separator having the line rib in the region facing the upper portion of the positive electrode plate and the region facing the upper portion of the negative electrode plate do not have the rib in one of the regions facing the upper portion of the electrode plate. It was found that all of the PSOC life, the low-temperature high-rate discharge performance, and the permeation short-circuit resistance were superior to the A1 battery of the comparative example using the separator. The A9 battery of Comparative Example 2 using a separator having no ribs in the region facing the upper part of the electrode plate and having the line ribs in the region facing the lower part of the electrode plate has a longer PSOC life and shorter permeation resistance than the A1 battery of Comparative Example 1. Had declined. This is presumed to be due to the fact that the spreading of the lower portion promoted the non-uniformity of the reaction and accelerated stratification and dendrite growth.

  B1 to B3 batteries using a separator having a dot-shaped rib have a PSOC life, a low-temperature and high-rate discharge performance higher than those of the A2, A3, and A5 batteries under the same conditions except that the rib has a line shape, and have the same or better performance. The anti-osmosis short circuit performance was shown. This is presumably because the increase in internal resistance was suppressed and the diffusivity of liquid and gas was improved.

From the above results, the following can be said with respect to the effect when the battery of the present invention is used as a lead storage battery for starting for an idling stop vehicle. The charge / discharge test shown in Table 3 is a typical charge / discharge pattern when mounted on an idling stop vehicle. By performing this test, the life performance as a lead storage battery for an idling stop vehicle (life under a so-called PSOC condition) Performance) can be evaluated. As a result of the above test, the number of cycles of the battery of the example was about 3% to 10% larger in the case of the linear rib than in the comparative example. From this result, using a separator provided with ribs in the region facing the upper part of the positive electrode plate and the region facing the upper part of the negative electrode plate, and as a lead storage battery for an idling stop vehicle, a lead storage battery having a configuration of A <B is used. When used, it can be said that the effect of suppressing the seepage short circuit in the upper part of the electrode plate, the effect of reducing the size of the strap, and the effect of achieving the PSOC life performance required for an idling stop vehicle can be simultaneously obtained.
In addition, when storing the electrode group that achieves the predetermined level of PSOC life performance in a battery case with the upper limit set by JIS etc. without reducing the size of the strap, the location of the separator rib is limited to one side only. It is also possible to adopt a method of reducing the layer thickness by increasing the amount of active material by that amount, or a method of improving the PSOC life performance other than increasing the amount of active material. However, there is no technology that is as effective as an increase in the amount of active material in the latter method, and there is a high possibility that sufficient performance cannot be achieved.
Further, in the case of A = B or A> B, the size of the strap cannot be reduced, so that the size of the electrode plate group must be limited in order to store it in the battery case of a specified size. Therefore, the amount of active material that greatly affects the life performance under PSOC conditions cannot be sufficiently increased, and as a result, the level of PSOC life performance required for an idling stop vehicle may not be achieved. Is high.

  According to the present invention, in a lead storage battery in which the ear group lengths A and A ′ directly below the strap are smaller than the upper electrode plate group lengths B and B ′, the penetration short circuit can be suppressed. Is expected to be applied to lead storage batteries and the like.

A Ear group length just below the strap B B Distance between the pole plates located at both ends of the pole of the same polarity in the upper frame bone (upper plate group length)

Claims (6)

An electrode group in which a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween, an electrolytic solution, and a lead storage battery including a battery case containing the electrode plate group,
The length A between the outer ends of the ears directly below the negative electrode strap connecting the ears of the negative electrode plate and the length A 'between the outer ends of the ears immediately below the positive electrode strap connecting the ears of the positive electrode plate are A'. The length B, B ′ between the outer ends in the stacking direction of the upper frame bones of the pole plates located at both ends of the pole plates connected to the respective straps,
The separator ribs in a region facing said negative electrode plate including a region facing the upper 50% or less of the area of the region and the negative electrode plate facing the positive electrode plate including an upper 50% or less of the area and facing region of the positive electrode plate A lead storage battery for an idling stop vehicle, comprising: The separator, in one aspect, the positive electrode plate has an entire surface with opposing regions or ribs on the negative electrode plate entirely with opposite area, the other surface, the region facing the upper 50% or less of the area of the positive electrode plate only, 2. The lead-acid battery according to claim 1, wherein a rib is provided only in an area facing an area of 50% or less of an upper part of the negative electrode plate. 3. The shape of the rib, a lead acid battery according to claim 1 or claim 2 characterized in that it is a dot shape. The lead-acid battery according to any one of claims 1 to 3, wherein a difference between the length A and the length B and a difference between the length A 'and the length B' are 1 mm or more . The separator, a lead acid battery according to claim 1 Neu deviation or claim, characterized in that a main component of polyethylene. The separator according to claim 1, wherein the surface facing one of the electrode plates has a structure in which the rib is cut out in a region facing a part or all of a lower portion of the electrode plate . lead-acid battery according to one term or shift have.