JP2013206839A - Lead acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead acid battery which, by properly designing the lattice skeleton of a lattice substrate of a cathode plate, does not reduce the amount of an active material to be held on the lattice substrate and which also can maintain a long life.SOLUTION: A lead acid battery comprises a cathode plate holding an active material on a lattice substrate and an anode plate holding an active material on the lattice substrate, which are each housed in an outer case. The lattice substrate has the relationships of the expression (1) and the expression (2) below. Expression (1): 0.55≥S1/S≥0.45 and expression (2): 0.50≥R/L≥0.30, where S=area enclosed by contour lines when the lattice substrate is seen in a plan view, S1=area other than a cavity portion area when a lattice skelton region is seen from the area S in a plan view, R=radius of a maximum circle which can be drawn within a lattice skeleton section at a portion where an area appearing in the lattice skeleton section when the lattice substrate is cut in thickness direction becomes minimum, and L=height in the thickness direction of the lattice substrate of the lattice skeleton at a portion where the area becomes minimum.

Description

  The present invention relates to a lead storage battery in which a positive electrode plate holding an active material on a lattice substrate and a negative electrode plate holding an active material on the lattice substrate are housed in an outer case.

An electrode plate widely used for lead-acid batteries is manufactured through a maturing / drying process by holding a paste-like active material on a lattice substrate formed of lead or a lead alloy.
The lattice substrate has a structure as shown in FIG. 1 for the purpose of holding the paste-like active material. That is, the lattice substrate 1 is provided with a lattice bone portion 3 composed of longitudinal bones 4 and transverse bones 5 and connected to the frame bone portion 2 inside the frame bone portion 2. The horizontal bone 5 has a lattice shape. The frame 2 is provided with ears 6 for current collection protruding from the outer periphery.

Lead storage batteries are strongly required to have a longer service life, and various measures have been taken to extend the service life as much as possible, maintaining the discharge capacity of lead storage batteries, suppressing the deterioration rate, and suppressing cost increases. A lattice substrate has been designed after examination.
Specifically, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-332268), the total cross-sectional area of all longitudinal bones in the long side direction of the lattice substrate is summed, and the total value is the dimension in the long side direction of the lattice substrate. It has been disclosed to extend the life by adjusting the divided value to 0.15 or more.

JP 2001-332268 A

However, the design freedom of the grid substrate is limited by the capacity and appearance dimensions of the lead storage battery. When creating a large lattice substrate, if the bones of the lattice bone (vertical and horizontal bones) are too thick, the total number of bones will have to be reduced, so the distance between the bones becomes wide and the active material is sufficient. There is a concern that the active material may not fall off and cause the active material to fall off.
On the other hand, if the bone of the lattice bone portion is made too thin, there is a concern that the electrode plate collapses preferentially due to bone corrosion mainly in the positive electrode plate.
The invention of Patent Document 1 is intended to increase the cross-sectional area of the lattice bone portion in the same direction as the long side direction of the lattice substrate in conjunction with increasing the dimension in the long side direction of the lattice substrate. However, simply increasing the cross-sectional area may not change the thickness by increasing the width of the lattice bone, or may not increase the width by increasing the thickness of the lattice bone. It is hard to say that consideration is given to corrosion that occurs from the surface toward the core.
It is an object of the present invention to provide a lead-acid battery that can maintain a long life without reducing the amount of active material held on the lattice substrate by appropriately designing the lattice portion of the lattice substrate of the positive electrode plate. To do.

In order to solve the above problems, the present invention is a lead-acid battery in which a positive electrode plate holding an active material on a lattice substrate and a negative electrode plate holding an active material on the lattice substrate are housed in an exterior case, The frame is composed of a frame bone and a lattice bone composed of vertical and horizontal bones, and the periphery of the lattice bone is connected to the frame bone. The lattice substrate of the positive electrode plate has a relationship of the following formulas (1) and (2) (claim 1).
0.55 ≧ S1 / S ≧ 0.45 (1)
0.50 ≧ R / L ≧ 0.30 (2)
However, S: Area surrounded by outline when the lattice substrate is viewed in plan S1: Area excluding void area when the lattice bone region is viewed in plan from the area S R: The lattice substrate is cut in the thickness direction The radius of the maximum circle that can be drawn in the cut surface at the portion where the area appearing on the lattice bone section cut surface is minimum L: the height in the lattice substrate thickness direction of the lattice bone portion at the portion where the area is minimum In the invention, the grid substrate of the positive electrode plate and the grid substrate of the negative electrode plate constituting the lead storage battery have a relationship of the following formula (3) (Claim 2).
2.7 ≧ MP / MN ≧ 2.5 Formula (3)
MP: total mass of the positive electrode plate lattice substrate constituting the lead storage battery MN: total negative electrode plate lattice substrate mass constituting the lead storage battery

According to the configuration of the present invention, the lattice bone for holding the active material based on the formula (1) even if the area surrounded by the outline when the grid substrate of the positive electrode plate is viewed in plan is the same The void area of the partial region is set appropriately, and a sufficient amount of active material is secured so that the battery capacity is not impaired. Moreover, the minimum bone thickness (distance from the surface of the lattice bone portion to the core portion) of the lattice bone portion is appropriately ensured based on the formula (2), and the early collapse of the positive electrode plate due to the corrosion of the bone is suppressed, and the lead storage battery Long life can be achieved.
In addition, if the grid substrate of the positive electrode plate and the grid substrate of the negative electrode plate constituting the lead storage battery have the relationship of the formula (3), it is possible to further appropriately increase the height while suppressing the early collapse of the positive electrode plate due to bone corrosion. There is an effect of increasing the capacity.

It is a schematic diagram of the lattice substrate of a lead storage battery electrode plate. In the lattice substrate of the lead-acid battery positive plate, (a) shows an area S surrounded by an outline when the lattice substrate is viewed in plan, and (b) is a gap portion when the lattice bone region is viewed in plan from the area S. It is explanatory drawing which showed area S1 except the area. The filled portions are area S and area S1. In the grid substrate of the lead-acid battery positive plate, the radius R of the maximum circle that can be drawn in the cut surface at the portion where the area appearing on the grid bone section cut surface when the grid substrate is cut in the thickness direction and the area is the minimum It is explanatory drawing which showed the lattice board thickness direction height L of the lattice bone part in the site | part which becomes. (A) shows the case where R / L is relatively small, and (b) shows the case where it is large. It is explanatory drawing which showed the structure of the lead acid battery. It is the graph which contrasted the relationship between the actual use equivalent years by integration of discharge in the accelerated life test, and the amount of corrosion of the grid substrate of the positive electrode plate in Examples and Comparative Examples.

<Frame bone part>
The frame part described in the present invention forms the outer shape of the grid substrate of the electrode plate described later, and it is preferable to match the inner shape of the exterior case of the lead storage battery to be used finally, more specifically. In this case, a square or rectangular shape in plan view can be used.
The thickness of the frame bone portion is not particularly limited, but preferably about 1 to 6 mm. This is because if the thickness is less than 1 mm, the physical strength is insufficient, handling at the time of manufacturing the lattice substrate is deteriorated, and it becomes difficult to manufacture the lattice substrate by the gravity casting method. On the other hand, in the case of a lattice substrate having a frame frame portion thicker than 6 mm, it becomes difficult to fill the paste-like active material uniformly to the back surface without exposing the lattice frame portion.
The frame bone portion is mainly made of lead, and tin, calcium, antimony, or the like can be used as an alloy component for this, and it is preferable to use both tin and calcium. This is because the addition of calcium can suppress self-discharge, while the addition of calcium can easily inhibit the corrosion of the lattice bone by adding tin.

<Lattice bone>
The lattice bone portion of the positive electrode plate described in the present invention is located and connected to the frame bone portion surrounded by the frame bone portion described above. More specifically, they are arranged so as to form a lattice composed of longitudinal bones and transverse bones.
The vertical bones and horizontal bones forming the lattice maintain the outer shape of the frame bone part, and have a function of holding an active material and a function of collecting current, which will be described later. ) And formula (2).
Longitudinal and transverse bones need not all have the same thickness, and can be a mixture of thick bones and fine bones that are thinner than these thick bones. It is preferable to arrange one or a plurality of fine bones between the thick bones and the thick bones. This is because when the thin bones are arranged between the thick bones, the paste-like active material is filled into the lattice substrate from one side (front side) to the back side rather than continuously arranging the thick bones. This is because it becomes easier to wrap around the back surface.
The thickness of the thin bone does not necessarily need to be one type, and a plurality of types can be used that are thinner than the thickness of the thick bone. In addition, the vertical bone and the horizontal bone can be arranged only in one of them, the thick bone and the thin bone, and the other can be all the same thickness, but from the ease of wrapping around the back surface of the paste-like active material It is preferable that both the longitudinal bone and the transverse bone have a thick bone and a thin bone.
The material of the longitudinal bone and the lateral bone forming the lattice bone portion may be the same as or different from the frame bone portion described above, but the frame bone portion and the lattice bone portion can be easily and integrally cast together. Thus, it is preferable to use the same material.

<Lattice substrate>
The lattice substrate of the positive electrode plate described in the present invention has the frame bone portion and the lattice bone portion described above, and satisfies the expressions (1) and (2).
Describing in detail with reference to FIG. 2, S is an area surrounded by an outline when the lattice substrate is viewed in plan view, and as shown in FIG. 2A, if the lattice substrate 1 is square, It can be calculated by “vertical dimension × horizontal dimension” of the frame 2.
In addition, although the ear | edge part etc. which collect current can be formed in the outer peripheral part of the frame frame part 2, when calculating S, it calculates by removing additional parts, such as an ear | edge.
As shown in FIG. 2B, S1 is an area obtained by removing the gap area when the lattice bone 3 region is viewed in plan from the area S described above.
Setting S1 / S to 0.45 or more is to increase the radius of the maximum circle that can be drawn on the cut surface of the lattice bone when the lattice substrate of the positive electrode plate is cut in the thickness direction. By doing so, it is possible to prevent shortening of the life due to bone corrosion.
S1 / S is 0.45 to 0.55, and more preferably about 0.5. When S1 / S is less than 0.45, the lattice bone portion is too thin, and the active material easily falls off. In addition, the collapse of the electrode plate due to lattice bone corrosion is accelerated. On the other hand, if S1 / S exceeds 0.55, the amount of the active material filled in the grid substrate of the positive electrode plate is insufficient and the battery capacity is impaired.

<Lattice bone cross section>
As shown in FIG. 3, the grid bone portion of the positive electrode plate has the radius of the maximum circle that can be drawn in the cut surface at the portion where the area appearing on the grid bone cut surface when the grid substrate is cut in the thickness direction is minimum. R is L, and L / L is 0.30 to 0.50, where L is the height in the lattice substrate thickness direction of the lattice bone portion at the part.
As described above, the size of the cross-sectional area when the lattice bone part is cut in the thickness direction of the lattice substrate is preferably mixed with thick bones and thin bones to be different depending on the part. good.
When the cross-sectional areas are different, R / L is calculated at an arbitrary part when the cross-sectional areas are the same at the smallest part. R / L is 0.50 at the maximum when the cross-sectional shape of the lattice bone portion is square, and becomes a smaller value as the amount of deformation from the square is larger, but by setting it to 0.30 at the minimum, The radius of the maximum circle that can be drawn on the cut surface of the lattice part of the positive electrode plate is increased, and the durability against corrosion is increased.
When R / L is less than 0.25, as the value decreases, the cross-sectional shape gradually increases in the thickness direction of the lattice substrate, and even if the cross-sectional area is sufficient, The radius R of the maximum circle that can be drawn becomes small, and the lattice bone part collapses due to corrosion.

<Active material>
The active material described in the present invention is not particularly limited, but kneaded lead powder containing lead monoxide, water, sulfuric acid, etc. (cut fiber, carbon powder, lignin, sulfuric acid according to the characteristics of the positive electrode and the negative electrode) In some cases, additives such as barium and red lead may be added).
In addition, the active material can be filled by various methods. The active material in a paste form is filled into the lattice substrate while applying pressure from one side to the back side, and this active material is further added to the roller. To push in. In this way, the work can be performed so that the vertical and horizontal bones are not exposed from the filled active material.

<Lead battery>
The lead-acid battery described in the present invention uses the above-described electrode plate in which the lattice substrate is filled with an active material as the positive electrode plate, and is not limited thereto.
As a lead-acid battery, in addition to the positive electrode plate, a battery case in which the positive electrode plate is installed, a negative electrode plate, a separator for preventing a short circuit between the positive electrode plate and the negative electrode plate, an electrolytic solution, and the like are used, and these are conventionally used. Can be used as appropriate.

<Total mass ratio of grid substrate of positive electrode plate and negative electrode plate>
The total mass ratio of the positive electrode plate and the negative electrode plate constituting the lead storage battery is not particularly limited. However, the positive electrode plate lattice mass: MP and the negative electrode plate lattice mass: MN , MP / MN is preferably 2.5 to 2.7.
As the MP / MN value decreases, the proportion of the negative electrode plate gradually increases. If the capacity of the battery case is determined, the proportion of the positive electrode plate is inevitably reduced, so that sufficient battery capacity cannot be secured.
Further, as the MP / MN value increases, the ratio of the positive electrode plate to the negative electrode plate inevitably increases, and the battery capacity becomes balanced.
Note that the total mass of the lattice substrate means an integrated (total) value of the masses of all the lattice substrates used for each of the positive electrode plate and the negative electrode plate constituting the lead storage battery. When the same number of positive plates and negative plates are installed in the lead storage battery, the mass ratio between one grid substrate of the positive plate and one grid substrate of the negative plate may be calculated. When different numbers of the negative electrode plates are provided, the mass ratio is calculated by adding up all the masses of the respective lattice substrates. Note that the mass of the lattice substrate includes the mass of the ears provided in the frame bone and the legs provided as necessary.

Examples of the present invention will be described in detail below.
Example 1
A lead alloy containing tin: 1.0 to 1.8% by mass and calcium: 0.05 to 0.1% by mass was melted, and a grid substrate for a positive electrode plate was produced by a gravity casting method.
The lattice substrate 1 includes a lattice bone portion 3 similar to the example shown in FIG. 1 in the arrangement pattern of the longitudinal bones 4 and the horizontal bones 5 inside the frame bone portion 2. In the lattice substrate 1, the longitudinal bone 4 and the lateral bone 5 are each composed of a thick bone and a thin bone. The thickness of the thick bone is set to be smaller than the thickness of the frame bone portion 2.
That is, the end surface on the one end side in the thickness direction of the thick transverse bone and the end surface on the other end side are arranged on the inner side in the thickness direction of the end surface on the one end side in the thickness direction and the end surface on the other end side. In addition, the end face on one end side and the end face on the other end side in the thickness direction of the thick vertical bone are disposed on the inner side in the thickness direction with respect to the end face on one end side in the thickness direction and the end face on the other end side.
The width and thickness of the thin horizontal bone are set smaller than the width and thickness of the thick horizontal bone, respectively, and the width and thickness of the thin vertical bone are set smaller than the width and thickness of the thick vertical bone, respectively.
Furthermore, each thin transverse bone and thin longitudinal bone are positioned at positions where the end faces on one end side in the thickness direction are biased toward the plane where the end faces on one end side in the thickness direction of the thick transverse bone and thick longitudinal bone are arranged. It is provided in the state. More specifically, the lattice substrate 1 has an end face on one end side in the thickness direction of the thin vertical bone and the thin horizontal bone arranged in an upward direction when the active material is filled. It was located on the same plane as the end face on one end side in the direction.

In the lattice substrate 1 described above, the frame frame 2 has a vertical dimension of 385 mm, a horizontal dimension of 140 mm, a thickness of 5.8 mm, and a width of 4.4 mm. A longitudinal bone 4 with bones and a transverse bone 5 with thick and thin transverse bones were formed. The cross-sectional shapes of the thick longitudinal bone and the thick transverse bone were hexagons having a thickness larger than the width, the thickness was 5.4 mm, and the width was 4.3 mm. Further, the cross-sectional shapes of the thin vertical bone and the thin horizontal bone were also hexagons having a thickness larger than the width, and each thickness (ie, L) was 3.6 mm and the width was 2.8 mm.
The lattice substrate 1 was filled with a paste-like positive electrode active material with a paste filling machine, and then aged and dried to produce an unformed positive electrode plate.
The paste-like positive electrode active material was mixed by adding 0.1% by mass of polyester fiber to the mass of lead powder containing lead monoxide as a main component, and then mixed with 12% by mass of water and 16% by mass of dilute sulfuric acid. In addition, it knead | mixed and produced. The method for producing the positive electrode active material is the same as the conventional method.

Moreover, what was produced by the method shown below was used as a lattice board | substrate for negative electrode plates.
A lead alloy containing 1.8-2.2% by mass of tin and 0.8-1.2% by mass of calcium is melted, and the vertical dimension of the frame bone portion is 385 mm, the horizontal dimension is 140 mm, and the thickness by the gravity casting method. A negative electrode grid substrate having a thickness of 3.0 mm was produced. The transverse bone and longitudinal bone inside the frame bone were all formed by a lattice bone having a hexagonal cross-sectional shape with a thickness of 2.6 mm and a width of 1.8 mm.
The negative electrode grid substrate 1 was filled with a paste-like negative electrode active material by a paste filling machine, and then aged and dried to produce an unformed negative electrode plate.
First, the paste-like negative electrode active material is composed of 0.2% by mass of lignin and 0.1% by mass of barium sulfate with respect to the mass of the lead powder containing lead monoxide as a main component. Add 0.2% by mass of carbon powder and 0.1% by mass of polyester fiber, mix, then add 12% by mass of water and knead, then add 13% by mass of dilute sulfuric acid and knead again. Made. The method for producing the negative electrode active material is the same as a conventional method.
The positive electrode plate and the negative electrode plate are alternately laminated one by one with a separator interposed therebetween (configuration of 24 positive electrode plates and 25 negative electrode plates), and the ears of the same polarity electrode plates are connected with straps. The electrode group was produced by linking. After this electrode plate group was put in a battery case, dilute sulfuric acid was injected and chemical conversion was performed to obtain a 2V lead acid battery.

Examples 2 to 5, Comparative Examples 1 to 3, Conventional Example 1
While maintaining the outer dimensions of the first embodiment, the positive and negative electrode plates satisfying the expression (3), the expression (1) and the expression (2) and the positive electrode not satisfying the expression (3). The examination of the plate lattice substrate is carried out, some are selected as examples and comparative examples, and the corrosion amount and battery capacity of each example are compared. Specifically, MP / MN is fixed at 2.70. In S1 / S, S is fixed and S1 is variable, that is, the width and number of the bones of the lattice bone are changed. Moreover, in R / L, L was fixed and R was variable, that is, the width of the bone of the lattice bone portion was changed.
About the lead acid battery of each example, the discharge capacity | capacitance and the corrosion degree of the lattice part of the positive electrode plate grid board | substrate were confirmed.
The capacity evaluation is based on the standards of the Battery Industry Association, and 10 HR (10 hour rate) discharge is performed from a fully charged lead acid battery (single cell), and the battery voltage is 1.8 V (end voltage). ) Calculate the discharge capacity from the discharge time until it reaches). For example, a unit cell with a nominal capacity of 1500 Ah is discharged at 150 A, and the time to reach the end voltage is 750 Ah for 5 hours and 1500 Ah for 10 hours.
Corrosion evaluation is performed by subjecting the lead-acid battery to repeated charging and discharging, disassembling the lead-acid battery at a joint, and taking out the positive grid substrate. The oxidation corrosion layer of the positive grid substrate is dissolved and removed with an alkaline solution, and the mass of the washed grid substrate is measured to determine the difference from the initial mass. It can be said that the smaller the difference, the less the corrosion amount.
The evaluation is that the lower the progress of the corrosion, the better the discharge capacity is equal to or higher, and the results are shown in Table 1 with “◯” and “×”. The determination of “◯” or “×” means the following.
In corrosion evaluation, ○: superior to conventional technology
×: Less than or equal to conventional technology In capacity evaluation, ○: Same or more than conventional technology
×: Lower than conventional technology

As apparent from Table 1, Examples 1 to 5 exceeded the prior art (conventional example 1) in corrosion evaluation, and a discharge capacity equal to or higher than that of the prior art was obtained. Comparative Examples 1-3 were inferior to the prior art in discharge capacity or corrosion evaluation.
In Example 3 and Comparative Example 2, S1 / S is smaller than that in Example 1 and the amount of positive electrode active material is larger than that in Example 1. However, the discharge capacity is dominated by the amount of negative electrode active material. Since the amount of negative electrode active material does not change between 3 and Comparative Example 2, there is almost no difference in discharge capacity.

Next, a single plate battery using the positive electrode plate in Examples 1 to 5, Comparative Example 1 and Comparative Example 2 was prepared, and an accelerated life test in which charging / discharging was repeated at a high temperature (75 ° C.) was conducted. The relationship between the number of years of use and the amount of corrosion of the grid substrate of the positive electrode plate was determined, and the results are shown in FIG.
In FIG. 5, when the corrosion rate of the grid substrate of the positive electrode plate progresses and the rate of corrosion with respect to the initial value reaches a predetermined value, the corrosion amount is 100, and the equivalent number of years at that time is the estimated life. The rate of corrosion relative to the initial stage is at a site where the area appearing on the lattice bone cut surface is minimized.
Comparing Examples 1 to 5 with Comparative Examples 1 and 2, it can be seen that the life has reached 17 years of actual use in the Examples, and 10 years of actual use in the Comparative Examples.
In FIG. 5, in the region where the amount of corrosion exceeds 100, the corrosion of the lattice bone portion has progressed to the core portion, and the lattice substrate is no longer self-supporting and cannot maintain its shape.

Examples 6-8
Next, in Example 1, the amount of active material filled in the grid substrate is constant, the number of negative electrode plates is fixed, and the total number of the positive electrode plate and negative electrode plate lattice ratios is changed by changing the number of positive electrode plates. That is, the discharge capacity and the battery capacity when the MP / MN was changed were compared with those in Example 1.
Specifically, Example 1 has one fewer positive electrode plate than the negative electrode plate.
In Example 6, the number of positive electrode plates is reduced by one from that of Example 1, and the number of positive electrode plates is two less than that of the negative electrode plate.
In Example 7, the number of positive plates is increased by one from Example 1, and the number of positive plates and negative plates is the same.
In Example 8, the number of positive electrode plates is reduced by 2 from Example 1, and the number of positive electrode plates is 3 less than that of the negative electrode plate.
In Examples 6 and 7 in which the number of positive electrode plates is two or more less than that of the negative electrode plate, the negative electrode plates are partially stacked adjacent to each other.
If the discharge capacity is the same, the smaller the battery volume is, the better the evaluation is. Table 2 shows “◯” and “×”. The determination of “◯” or “×” means the following.
Capacity evaluation: ○: Same as or better than Example 1
X: less than Example 1 Battery case volume is equal to or less than ○: Example 1
X: Exceeding Example 1

  As is clear from Table 2, Example 6 had the same battery capacity and battery case volume as Example 1. In Example 7, the battery case volume increased from that in Example 1. Moreover, although Example 8 was superior to the conventional example, the battery capacity was smaller than that of Example 1.

1: Lattice substrate 2: Frame bone portion 3: Lattice bone portion 4: Longitudinal bone 5: Horizontal bone

Claims (2)

A lead-acid battery in which a positive electrode plate holding an active material on a lattice substrate and a negative electrode plate holding an active material on the lattice substrate are housed in an outer case, the lattice substrate comprising a frame bone portion, vertical bones and horizontal bones It is composed of a lattice bone, and the periphery of the lattice bone is connected to the frame bone,
The lead-acid battery, wherein the grid substrate of the positive electrode plate has a relationship of the following formulas (1) and (2).
0.55 ≧ S1 / S ≧ 0.45 (1)
(However, S: the area surrounded by the outline when the lattice substrate is viewed in plan, S1: the area excluding the void area when the lattice bone region is viewed in plan from the area S)
0.50 ≧ R / L ≧ 0.30 (2)
(However, R: radius of the maximum circle that can be drawn in the cut surface at the portion where the area appearing on the lattice bone section cut surface when the lattice substrate is cut in the thickness direction, L: at the portion where the area is minimized. (Lattice height in the direction of the thickness of the lattice substrate) The lead storage battery according to claim 1, wherein the grid substrate of the positive electrode plate and the grid substrate of the negative electrode plate constituting the lead storage battery have a relationship of the following formula (3).
2.7 ≧ MP / MN ≧ 2.5 Formula (3)
(However, MP: the total mass of the grid substrate of the positive electrode plate constituting the lead storage battery, MN: the total mass of the grid substrate of the negative electrode plate constituting the lead storage battery)