JP7057465B1 - Bipolar lead acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion between a lead foil made of a lead alloy having high corrosion resistance and an active material layer in a bipolar storage battery provided with a lead foil made of a lead alloy having high corrosion resistance as a current collector. SOLUTION: A positive electrode lead foil and a negative electrode lead foil have a portion having a granular structure, and an interface between the positive electrode lead foil 111a and a positive electrode active material layer 111b and a negative electrode active material layer of the negative electrode lead foil 112a. At least one of the interfaces with 112b has a portion formed in a granular structure, and the ten-point average roughness (RzJIS) according to the provisions of "JIS B 0601: 2013 Annex JA" is 50 μm or more. The specified maximum height roughness (Rz) is smaller than 1/2 of the average particle size of the particles constituting the granular structure. [Selection diagram] Fig. 1

Description

The present invention relates to a bipolar lead-acid battery.

In recent years, the number of power generation facilities that use natural energy such as solar power and wind power has increased. In such a power generation facility, since the amount of power generation cannot be controlled, a storage battery is used to equalize the power load. That is, when the amount of power generation is larger than the consumption amount, the difference is charged to the storage battery, while when the amount of power generation is smaller than the consumption amount, the difference is discharged from the storage battery. As the above-mentioned storage battery, a lead storage battery is often used from the viewpoint of economy, safety and the like. As such a conventional lead-acid battery, for example, the bipolar lead-acid battery described in Patent Document 1 below is known.

This bipolar lead-acid battery has a frame shape and a resin substrate is attached to the inside of a resin frame. Lead layers are arranged on both sides of the substrate. The lead layer on one surface of the substrate is adjacent to the active material layer for the positive electrode, and the lead layer on the other surface is adjacent to the active material layer for the negative electrode. Further, it has a frame-shaped and resin spacer, and a glass mat impregnated with an electrolytic solution is arranged inside the spacer. Then, a plurality of frames and spacers are alternately laminated, and the frames and spacers are bonded with an adhesive or the like. Further, the lead layers on both sides of the substrate are connected via the through holes provided in the substrate.

That is, the bipolar lead storage battery described in Patent Document 1 is a positive electrode lead foil having a positive electrode active material layer arranged on one surface of a positive electrode lead foil made of lead or a lead alloy, and a negative electrode lead foil made of lead or a lead alloy. A plurality of cell members and a plurality of cell members, which are provided with a negative electrode in which an active material layer for a negative electrode is arranged on one surface and a separator (glass mat) interposed between the positive electrode and the negative electrode, and are laminated and arranged at intervals. It has a plurality of space forming members, which form a plurality of spaces individually accommodating the cell members.

Further, the space forming member includes a substrate that covers at least one of the positive electrode side and the negative electrode side of the cell member, and a frame body (a frame portion and a spacer of a bipolar plate and an end plate) that surrounds the side surface of the cell member. I'm out. Further, the substrate of the cell member and the substrate of the space forming member are alternately arranged in a laminated state, and the substrate arranged between the adjacent cell members has a through hole extending in a direction intersecting the plate surface, and the through hole is formed. Inside, the lead foil for the positive electrode and the lead foil for the negative electrode of the adjacent cell members are conductive, and a plurality of cell members are electrically connected in series, and the adjacent frames are joined.

Japanese Patent No. 6124894

One of the causes of deterioration of lead-acid batteries is corrosion of the positive electrode current collector plate. As the battery usage period becomes longer, the corrosion of the positive electrode current collector plate progresses, and if the corrosion progresses, the positive electrode active material cannot be retained, and the performance as a battery deteriorates. Not only that, if the positive electrode material (positive electrode current collector plate or positive electrode active material) that has fallen off due to corrosion comes into contact with the negative electrode, there is a possibility of a short circuit.
In particular, in the case of a bipolar lead-acid battery, since the current distribution is a reaction on the surface, it is not necessary to consider the charge transfer resistance, and the current collector plate can be made thinner, but the distance between the positive electrode and the negative electrode is short. Therefore, if the positive electrode current collector plate is heavily corroded, a fatal defect may occur. Therefore, it is necessary to suppress the corrosion of the positive electrode current collector plate. However, since a lead alloy having high corrosion resistance does not easily react with an active material, a lead foil made of a lead alloy having high corrosion resistance is inferior in adhesion to an active material layer.

An object of the present invention is to improve the adhesion between the lead foil made of a lead alloy having high corrosion resistance and the active material layer in a bipolar storage battery provided with a lead foil made of a lead alloy having high corrosion resistance as a current collector. ..

The first aspect of the present invention for solving the above-mentioned problems is a bipolar storage battery having the following configurations (1) to (4).
(1) The active material layer for the positive electrode is arranged on one surface of the lead foil for the positive electrode made of lead or a lead alloy, and the active material layer for the negative electrode is arranged on one surface of the lead foil for the negative electrode made of lead or a lead alloy. A plurality of cell members, which are provided with a negative electrode and a separator interposed between the positive electrode and the negative electrode, and which are stacked and arranged at intervals, and a plurality of spaces individually accommodating the plurality of cell members are formed. , With a plurality of space forming members.

(2) The space forming member includes a synthetic resin substrate that covers both the positive electrode side and the negative electrode side of the cell member, and a frame that surrounds the side surface of the cell member. The cell member and the substrate of the space forming member are arranged in a state of being alternately laminated. The adjacent frames are joined together.

(3) The lead foil for the positive electrode and the lead foil for the negative electrode have a portion having a granular structure. At least one of the interface between the lead foil for the positive electrode and the active material layer for the positive electrode and the interface between the lead foil for the negative electrode and the active material layer for the negative electrode has a portion formed in the granular structure and is described as ". The ten-point average roughness (RzJIS) according to the provisions of "Appendix JA of JIS B 0601: 2013" is 50 μm or more, and the maximum height roughness (Rz) according to the provisions is the average particle of the particles constituting the granular structure. It is smaller than 1/2 of the diameter.

(4) The substrate arranged between the adjacent cell members has a through hole extending in a direction intersecting the plate surface, and the lead foil for the positive electrode of the adjacent cell member in the through hole. And the lead foil for the negative electrode are conducted, and the plurality of cell members are electrically connected in series.

The bipolar lead-acid battery of the present invention is expected to have excellent adhesion between a lead foil (current collector plate) made of a lead alloy having high corrosion resistance and an active material layer.

It is sectional drawing which shows the schematic structure of the bipolar lead-acid battery which is one Embodiment of this invention. It is a partially enlarged view of the bipolar lead-acid battery of FIG. It is a micrograph showing the metal structure of the cross section of the No. 1 lead foil. It is a micrograph which shows the metal structure of the cross section of the lead foil of No.6.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments shown below. In the embodiments shown below, technically preferable limitations are made for carrying out the present invention, but these limitations are not essential requirements of the present invention.

〔overall structure〕
First, the overall configuration of the bipolar lead-acid battery of this embodiment will be described.
As shown in FIG. 1, the bipolar lead-acid battery 100 of this embodiment includes a plurality of cell members 110, a plurality of biplates (space forming members) 120, and a first end plate (space forming member) 130. , Has a second end plate (space forming member) 140. FIG. 1 shows a bipolar lead-acid battery 100 in which three cell members 110 are stacked, but the number of cell members 110 is determined by the battery design. Further, the number of bi-plates 120 is determined according to the number of cell members 110.

The stacking direction of the cell members 110 is the Z direction (vertical direction in FIGS. 1 and 2), and the direction perpendicular to the Z direction is the X direction.
The cell member 110 includes a positive electrode 111, a negative electrode 112, and a separator (electrolyte layer) 113. The separator 113 is impregnated with an electrolytic solution. The positive electrode 111 has lead foils for positive electrodes (current collector plates for positive electrodes) 111a and 111aa and an active material layer 111b for positive electrodes. The negative electrode 112 has a lead foil for the negative electrode (current collector plate for the negative electrode) 112a, 112aa and an active material layer 112b for the negative electrode. The separator 113 is interposed between the positive electrode 111 and the negative electrode 112. In the cell member 110, the lead foils 111a and 111aa for the positive electrode, the active material layer 111b for the positive electrode, the separator 113, the active material layer 112b for the negative electrode, and the lead foils 112a and 112aa for the negative electrode are laminated in this order.

The dimension (thickness) in the Z direction of the positive electrode lead foil 111a is larger (thicker) than that of the negative electrode lead foil 112a, and the positive electrode active material layer 111b is larger (thicker) than the negative electrode active material layer 112b.
The plurality of cell members 110 are stacked and arranged at intervals in the Z direction, and the substrate 121 of the biplate 120 is arranged at the portions of the intervals. That is, the plurality of cell members 110 are laminated with the substrate 121 of the biplate 120 sandwiched between them.

The plurality of bi-plates 120, the first end plate 130, and the second end plate 140 are members for forming a plurality of spaces (cells) C that individually accommodate the plurality of cell members 110.
As shown in FIG. 2, the biplate 120 includes a substrate 121 having a rectangular planar shape, a frame body 122 covering the four end faces of the substrate 121, and a pillar portion 123 vertically protruding from both sides of the substrate 121. The substrate 121, the frame body 122, and the pillar portion 123 are integrally formed of synthetic resin. The number of pillars 123 protruding from each surface of the substrate 121 may be one or a plurality.

In the Z direction, the dimension of the frame 122 is larger than the dimension (thickness) of the substrate 121, and the dimension between the protruding end faces of the pillar 123 is the same as the dimension of the frame 122. Then, a space C is formed between the substrate 121 and the substrate 121 by contacting and stacking the frame body 122 and the pillar portions 123 with each other, and the pillar portions 123 in contact with each other form a space. The dimension of C in the Z direction is retained.

The lead foils 111a and 111aa for the positive electrode, the active material layer 111b for the positive electrode, the lead foils 112a and 112aa for the negative electrode, the active material layer 112b for the negative electrode, and the separator 113 have through holes 111c, 111d, 112c through which the pillar portion 123 is penetrated. 112d and 113a are formed, respectively.
The substrate 121 of the biplate 120 has a plurality of through holes 121a penetrating the plate surface. A first recess 121b is formed on one surface of the substrate 121, and a second recess 121c is formed on the other surface. The depth of the first recess 121b is deeper than that of the second recess 121c. The dimensions of the first recess 121b and the second recess 121c in the X and Y directions correspond to the dimensions of the lead foil 111a for the positive electrode and the lead foil 112a for the negative electrode in the X and Y directions.

The substrate 121 of the biplate 120 is arranged between adjacent cell members 110 in the Z direction. The substrate 121 of the biplate 120 is a substrate that covers both the positive electrode 111 side of the cell member 110 and the negative electrode 112 side of the adjacent cell member 110. In the first recess 121b of the substrate 121 of the biplate 120, the lead foil 111a for the positive electrode of the cell member 110 is arranged via the adhesive layer 150. That is, the lead foil 111a for the positive electrode is fixed to the surface of the substrate 121 on the side of the positive electrode 111 (the bottom surface of the first recess 121b) with an adhesive.

Further, the lead foil 112a for the negative electrode of the cell member 110 is arranged in the second recess 121c of the substrate 121 of the biplate 120 via the adhesive layer 150. That is, the lead foil 112a for the negative electrode is fixed to the surface of the substrate 121 on the side of the negative electrode 112 (the bottom surface of the second recess 121c) with an adhesive.
The conductor 160 is arranged in the through hole 121a of the substrate 121 of the biplate 120, and both end faces of the conductor 160 are in contact with and bonded to the lead foil 111a for the positive electrode and the lead foil 112a for the negative electrode. That is, the lead foil 111a for the positive electrode and the lead foil 112a for the negative electrode are electrically connected by the conductor 160. As a result, all of the plurality of cell members 110 are electrically connected in series.

As shown in FIG. 1, the first end plate 130 is arranged on a substrate 131 that covers the positive electrode side of the cell member 110, a frame 132 that surrounds the side surface of the cell member 110, and one surface of the substrate 131 (most positive electrode side). It is composed of a pillar portion 133 that projects vertically from the surface of the biplate 120 facing the substrate 121). The planar shape of the substrate 131 is rectangular, the four end faces of the substrate 131 are covered with the frame 132, and the substrate 131, the frame 132, and the pillar 133 are integrally formed of synthetic resin. The number of the pillars 133 protruding from one surface of the substrate 131 may be one or a plurality, but the number of the pillars 133 may correspond to the pillars 123 of the biplate 120 in contact with the pillars 133.

In the Z direction, the dimension of the frame 132 is larger than the dimension (thickness) of the substrate 131, and the dimension between the protruding end faces of the column 133 is the same as the dimension of the frame 132. Then, the frame 132 and the pillar 133 are brought into contact with each other and laminated with respect to the frame 122 and the pillar 123 of the bi-plate 120 arranged on the outermost side (positive side), so that the substrate 121 of the bi-plate 120 is laminated. Space C is formed between the substrate 131 of the first end plate 130, and the Z-direction dimension of the space C is formed by the pillar portion 123 of the bi-plate 120 and the pillar portion 133 of the first end plate 130 that are in contact with each other. Is retained.

Through holes 111c, 111d, 113a through which the pillar portion 133 is penetrated are formed in the lead foil 111aa for the positive electrode, the active material layer 111b for the positive electrode, and the separator 113 of the cell member 110 arranged on the outermost side (positive electrode side), respectively. ing.
A recess 131b is formed on one surface of the substrate 131 of the first end plate 130. The dimension of the recess 131b in the X direction corresponds to the dimension of the lead foil 111aa for the positive electrode in the X direction. The Z-direction dimension of the positive electrode lead foil 111aa arranged on one surface of the substrate 131 of the first end plate 130 is larger than the Z-direction dimension of the positive electrode lead foil 111a arranged on one surface of the substrate 121 of the bi-plate 120. Is also big.

In the recess 131b of the substrate 131 of the first end plate 130, the lead foil 111aa for the positive electrode of the cell member 110 is arranged via the adhesive layer 150. That is, the lead foil 111aa for the positive electrode is fixed to the surface of the substrate 131 on the positive electrode 111 side (bottom surface of the recess 131b) with an adhesive.
Further, the first end plate 130 includes a positive electrode terminal electrically connected to a lead foil 111aa for a positive electrode in the recess 131b.

The second end plate 140 includes a substrate 141 that covers the negative electrode side of the cell member 110, a frame 142 that surrounds the side surface of the cell member 110, and one surface of the substrate 141 (the substrate 121 of the biplate 120 that is arranged on the most negative electrode side). It is composed of a pillar portion 143 that projects vertically from the surface facing the surface). The planar shape of the substrate 141 is rectangular, the four end faces of the substrate 141 are covered with the frame body 142, and the substrate 141, the frame body 142, and the pillar portion 143 are integrally formed of synthetic resin. The number of pillars 143 protruding from one surface of the substrate 141 may be one or a plurality, but the number of pillars 143 may correspond to the pillars 123 of the biplate 120 in contact with the pillars 143.

In the Z direction, the dimension of the frame 142 is larger than the dimension (thickness) of the substrate 131, and the dimension between the protruding end faces of the two pillars 143 is the same as the dimension of the frame 142. Then, the frame body 142 and the pillar portion 143 are brought into contact with the frame body 122 and the pillar portion 123 of the bi-plate 120 arranged on the outermost side (negative side), and the frame body 142 and the pillar portion 143 are brought into contact with each other and laminated to form the substrate 121 of the bi-plate 120. Space C is formed between the substrate 141 of the second end plate 140, and the Z-direction dimension of the space C is formed by the pillar portion 123 of the bi-plate 120 and the pillar portion 143 of the second end plate 140 that are in contact with each other. Is retained.

Through holes 112c, 112d, 113a through which the pillar portion 143 is penetrated are formed in the lead foil 112aa for the negative electrode, the active material layer 112b for the negative electrode, and the separator 113 of the cell member 110 arranged on the outermost side (negative electrode side), respectively. ing.
A recess 141b is formed on one surface of the substrate 141 of the second end plate 140. The dimensions of the recess 141b in the X and Y directions correspond to the dimensions of the lead foil 112aa for the negative electrode in the X and Y directions. The Z-direction dimension of the negative electrode lead foil 112aa arranged on one surface of the substrate 141 of the second end plate 140 is the Z-direction dimension of the negative electrode lead foil 112a arranged on the other surface of the substrate 121 of the bi-plate 120. Greater than.

In the recess 141b of the substrate 141 of the second end plate 140, the lead foil 112aa for the negative electrode of the cell member 110 is arranged via the adhesive layer 150. That is, the lead foil 112aa for the negative electrode is fixed to the surface of the substrate 141 on the side of the negative electrode 112 (the bottom surface of the recess 141b) with an adhesive.
Further, the second end plate 140 includes a negative electrode terminal electrically connected to a lead foil 112aa for a negative electrode in the recess 141b.

As can be seen from the above description, the biplate 120 is a space forming member including a substrate 121 that covers both the positive electrode side and the negative electrode side of the cell member 110 and a frame body 122 that surrounds the side surface of the cell member 110. .. The first end plate 130 is a space forming member including a substrate 131 that covers only the positive electrode side (one of the positive electrode side and the negative electrode side) of the cell member 110, and a frame 132 that surrounds the side surface of the cell member 110.

Further, the second end plate 140 is a space forming member including a substrate 141 that covers only the negative electrode side (one of the positive electrode side and the negative electrode side) of the cell member 110 and a frame body 142 that surrounds the side surface of the cell member 110. be. That is, the substrates 121, 131, 141 are substrates that cover at least one of the positive electrode side and the negative electrode side of the cell member 110, and the substrate 121 is a substrate that covers both the positive electrode side and the negative electrode side of the cell member 110. be. Further, the substrate 121 of the bi-plate 120 is a substrate arranged between the cell members 110.

[Construction of current collector plate]
The lead foil 111a for the positive electrode arranged in the recess 121b of the biplate 120 has, for example, a thickness of less than 0.5 mm (for example, 0.1 mm or more and 0.4 mm or less) and a tin (Sn) content of 1. A lead alloy having 0% by mass or more and 2.0% by mass or less, a calcium (Ca) content of 0.005% by mass or more and 0.030% by mass or less, and the balance being lead (Pb) and an unavoidable impurity. It is made of a heat-treated material of a rolled sheet made of. The structure of this heat-treated material is a granular structure.

The lead foil 111a for the positive electrode arranged in the recess 131b of the first end plate 130 has, for example, a thickness of 0.5 mm or more and 1.5 mm or less, and is formed of the same heat-treated material as the lead foil 111a for the positive electrode. ..
Further, the interface between the positive electrode lead foils 111a and 111aa with the positive electrode active material layer 111b has a ten-point average roughness (RzJIS) of 50 μm or more according to the provisions of “JIS B 0601: 2013 Annex JA”, and is described above. The specified maximum height roughness (Rz) is smaller than 1/2 of the average particle size of the particles constituting the granular structure of the lead foils 111a and 111aa for the positive electrode.

The thickness of the lead foil for the negative electrode (current collector plate for the negative electrode) 112a arranged in the recess 121c of the bi-plate 120 is, for example, 0.05 mm or more and 0.3 mm or less. The alloy forming the lead foil 112a for the negative electrode is, for example, a lead alloy having a tin (Sn) content of 0.5% by mass or more and 2% by mass or less.
The lead foil for the negative electrode (collecting plate for the negative electrode) 112a arranged in the recess 141b of the second end plate 140 has, for example, a thickness of 0.5 mm or more and 1.5 mm or less, and a tin (Sn) content. Is made of a lead alloy of 0.5% by mass or more and 2% by mass or less.

[Action, effect]
In the bipolar lead-acid battery 100 of the embodiment, since the lead foils 111a and 111aa for the positive electrode are heat-treated materials for the rolled sheet made of the lead alloy, the lead foils 111a and 111aa for the positive electrode have a granular structure. Therefore, the lead foils 111a and 111aa for the positive electrode have excellent corrosion resistance, and the interface with the active material layer 111b for the positive electrode is a surface of the granular structure. Further, the interface between the lead foils 111a and 111aa for the positive electrode and the active material layer 111b for the positive electrode has a ten-point average roughness (RzJIS) of 50 μm or more (configuration a) according to the above specification, and the maximum height roughness according to the above specification. (Rz) is smaller than 1/2 of the average particle diameter (A) of the particles constituting the granular structure of the positive electrode lead foils 111a and 111aa (configuration b).

As described above, the positive electrode lead foils 111a and 111aa are lead foils made of a lead alloy having high corrosion resistance, but the interface with the positive electrode active material layer 111b satisfies both the above configurations a and b, so that the positive electrodes are positive electrodes. It has high adhesion to the active material layer 111b. Along with this, the active material for the positive electrode is less likely to fall off from the lead foils 111a and 111aa for the positive electrode, so that high battery performance is maintained and a short circuit is prevented, so that the effect of improving the life of the bipolar lead-acid battery 100 is expected. can.

On the other hand, when the ten-point average roughness (RzJIS) at the interface between the positive electrode lead foils 111a and 111aa and the positive electrode active material layer 111b is less than 50 μm, the positive electrode active material layer 111b and the positive electrode active material layer 111b are used. Adhesion is extremely low. Further, when the maximum height roughness (Rz) of the positive electrode lead foils 111a and 111aa is A / 2 or more, the positive electrode lead foils 111a and 111aa are likely to be corroded, so that penetration is likely to occur.

In the bipolar lead-acid battery 100 of the above embodiment, the positive electrode lead foils 111a and 111aa are made of a lead alloy having a granular structure and high corrosion resistance, and the interface with the positive electrode active material layer 111b is configured with the above configuration a and b. It is supposed to satisfy both of the above. However, if the lead foils 112a and 112aa for the negative electrode are made of a lead alloy having a granular structure and high corrosion resistance, and the interface with the active material layer 112b for the negative electrode satisfies both the above configurations a and b. The same action and effect can be obtained for the negative electrode (high battery performance is maintained and short circuit is prevented by making it difficult for the active material to fall off).

Even if the metal structure of the lead foil is a granular structure, if the ten-point average roughness (RzJIS) at the interface with the active material layer is too large (the surface is too rough), the lead foil will be partially thinned. The risk of penetration of the lead foil during battery operation increases, so the RzJIS is preferably 50 μm or more and 70 μm or less. For the same reason, the maximum height roughness (Rz) is preferably larger than the ten-point average roughness (Rz) and preferably 1/7 or more and 1/2 or less of the average particle size.

[Preparation of lead foil]
The lead foils No. 1 to No. 6 shown in Table 1 were prepared. The thickness of each lead foil was set to 0.35 mm.
<Sample No.1>
The lead foil of sample No. 1 has a calcium (Ca) content of 0.030% by mass, a tin (Sn) content of 2.0% by mass, and the balance is lead (Pb) and lead, which is an unavoidable impurity. A rolled sheet of alloy is heat-treated at 310 ° C. for 5 minutes in an air atmosphere.

The cross section of the lead foil of sample No. 1 was photographed with an electron microscope perpendicular to the sheet surface and parallel to the rolling direction. The micrograph is shown in FIG. As can be seen from this image, the structure was a granular structure, and the average particle size was 160 μm.
When the surface condition of the lead foil of sample No. 1 was measured based on the provisions of "JIS B 0601: 2013 Annex JA", the ten-point average roughness (RzJIS) was 20 μm, and the maximum height roughness. (Rz) was 30 μm.

<Sample No.2>
One side of the lead foil prepared by the same method as sample No. 1 was rubbed with sandpaper No. 800, and the ten-point average roughness (RzJIS) was 30 μm and the maximum height roughness (Rz) was 45 μm. I tried to be. This was used as the lead foil of sample No.2. The produced lead foil had a granular structure similar to that of the No. 1 lead foil, and its average particle size was 160 μm.

<Sample No.3>
One side of the lead foil prepared by the same method as sample No. 1 was rubbed with No. 80 sandpaper, and the ten-point average roughness (RzJIS) was 50 μm and the maximum height roughness (Rz) was 60 μm. I tried to be. This was used as the lead foil of sample No.3. The produced lead foil had a granular structure similar to that of the No. 1 lead foil, and its average particle size was 160 μm.

<Sample No.4>
One side of the lead foil prepared by the same method as sample No. 1 was rubbed with No. 80 sandpaper, and the ten-point average roughness (RzJIS) was 50 μm and the maximum height roughness (Rz) was 70 μm. I tried to be. This was used as the lead foil of sample No. 4. The produced lead foil had a granular structure similar to that of the No. 1 lead foil, and its average particle size was 160 μm.

<Sample No.5>
One side of the lead foil prepared by the same method as sample No. 1 was rubbed with sandpaper No. 40, and the ten-point average roughness (RzJIS) was 70 μm and the maximum height roughness (Rz) was 110 μm. I tried to be. This was used as the lead foil of sample No. 5. The produced lead foil had a granular structure similar to that of the No. 1 lead foil, and its average particle size was 160 μm.

<Sample No.6>
The lead foil of sample No. 6 has a calcium (Ca) content of 0.030% by mass, a tin (Sn) content of 2.0% by mass, and the balance is lead (Pb) and lead, which is an unavoidable impurity. It is a rolled alloy sheet that has not been heat-treated, and one surface is rubbed with sandpaper No. 80 to have a ten-point average roughness (RzJIS) of 50 μm and a maximum height roughness (Rz JIS). Rz) is set to 70 μm.

Before rubbing the lead foil of sample No. 6 with sandpaper, a cross section perpendicular to the sheet surface and parallel to the rolling direction was photographed with an electron microscope. The micrograph is shown in FIG. As can be seen from this image, the tissue is a striped tissue.

[Corrosion test]
Corrosion tests were carried out for each lead foil of No. 1 to No. 6 by the following method.
Each lead foil is cut into test pieces having a width of 15 mm and a length of 70 mm, placed in sulfuric acid at 60 ° C. having a specific gravity of 1.28, and anodized continuously at a constant potential of 1350 mV (vs: Hg / Hg ₂ SO ₄ ) for 28 days. After that, the produced oxide was removed. Then, the mass was measured before and after the test, the amount of mass loss due to the test was calculated from the value, and the amount of mass loss per total surface area of the test piece was taken as the amount of corrosion. In addition, the cross section after the corrosion test (cross section perpendicular to the sheet surface and parallel to the rolling direction) was observed with an electron microscope (magnification 400 times) to investigate whether or not the lead foil had penetrated.

[Peeling test of active material layer]
[Making a bi-plate]
By injection molding of ABS resin, a biplate 120 having the shape shown in FIG. 1 was produced. The thickness of the substrate 121 of the biplate 120 is 2 mm. The bottom surface of the recess 121b and the recess 121c is a square having a side of 10.0 cm, and the depth of the recess 121b and the recess 121c is 0.37 mm.

[Making end plate]
The first end plate 130 and the second end plate 140 having the shapes shown in FIG. 1 were produced by injection molding of ABS resin. The thickness of the substrate 131 of the first end plate 130 and 141 of the second end plate 140 is 10 mm. The bottom surfaces of the recess 131b and the recess 141b are squares with a side of 10.0 cm cm and a depth of 1.52 mm.

[Assembly of bipolar lead-acid battery]
As the lead foil 111a for the positive electrode and the lead foil 112a for the negative electrode to be arranged in the recess 121b and the recess 121c, the lead foils of Samples No. 1 to No. 6 were cut into squares having a side of 9.0 cm. All other parts were the same, and the No. 1 to No. 6 bipolar lead-acid batteries having the structure shown in FIG. 1 and having a nominal voltage of 6 V were assembled by a usual method. That is, each bipolar lead-acid battery has the same configuration except for the surface condition of the surface of the lead foil for the positive electrode and the lead foil for the negative electrode on the active material layer side.

The positive electrode active material layer 111b was 1.8 mm thick and was formed on the surfaces of the positive electrode lead foils 111a and 111aa. The negative electrode active material layer 112b was 1.6 mm thick and was formed on the surfaces of the negative electrode lead foils 112a and 112aa. As the separator 113, one made of glass fiber was used. As the electrolytic solution, dilute sulfuric acid having a concentration usually used was used.

[Observation of the peeled state of the active material layer]
After chemical conversion of the assembled No. 1 to No. 6 bipolar lead-acid batteries under normal conditions, each bipolar lead-acid battery is disassembled, and the positive electrode lead foil 111a is used as the positive electrode active material layer 111b. The surface of the positive electrode lead foil 111a on the positive electrode active material layer 111b side was observed with a microscope. By this observation, it was investigated whether or not the active material remained in the lead foil 111a for the positive electrode. If there is a residue of the active material, it can be determined that the adhesion of the positive electrode active material layer 111b to the positive electrode lead foil 111a made of a lead alloy having high corrosion resistance is excellent.

[evaluation]
The results of the corrosion test and the peeling test are shown in Table 1 together with the surface condition of the lead foil.

The following can be seen from the results in Table 1.
The lead foils No. 1 to No. 5 are made of lead alloys with a granular structure and therefore have high corrosion resistance. However, although the lead foils of No. 1 and No. 2 satisfy "Rz <A / 2", they do not satisfy "RzJIS ≧ 50 μm", so that the adhesion of the active material layer is low. Further, although the lead foil of No. 5 satisfied "RzJIS ≧ 50 μm", it did not satisfy "Rz <A / 2", so that the lead foil penetrated. On the other hand, the lead foils of No. 3 to No. 4 satisfy both "Rz <A / 2" and "RzJIS ≧ 50 μm", so that the active material layer has high adhesion and penetrates the lead foil. It did not occur.

Furthermore, the lead foil of No. 6 had low corrosion resistance because it was made of a lead alloy having a striped structure.
Therefore, according to the bipolar lead-acid battery using the lead foils of No. 3 to No. 4 as the lead foil for the positive electrode, the active material for the positive electrode is less likely to fall off from the lead foil for the positive electrode, so that high battery performance is maintained. It is estimated that the life of the lead-acid battery will be longer than that of the bipolar lead-acid battery using the lead foils of No. 1, No. 2, and No. 6 as the lead foil for the positive electrode.

100 Bipolar lead-acid battery 110 Cell member 111 Positive electrode 112 Negative electrode 111a Lead electrode for positive electrode 111aa Lead foil for positive electrode (collector plate for positive electrode)
111b Active material layer for positive electrode 112a Lead foil for negative electrode 112aa Lead foil for negative electrode (current collector plate for negative electrode)
112b Active material layer for negative electrode 113 Separator 120 Bi-plate 121 Bi-plate substrate (substrate arranged between adjacent cell members)
121a Through hole of the substrate 121b First recess of the substrate 121c Second recess of the substrate 122 Bi-plate frame 130 First end plate 131 First end plate substrate 132 First end plate frame 140 No. Second end plate 141 Second end plate substrate 142 Second end plate frame 150 Adhesive layer 160 Conductor C cell (space for accommodating cell members)

Claims (1)

A positive electrode having a positive electrode active material layer arranged on one surface of a positive electrode lead foil made of lead or a lead alloy, and a negative electrode having a negative electrode active material layer arranged on one surface of a negative electrode lead foil made of lead or a lead alloy. And a plurality of cell members provided with a separator interposed between the positive electrode and the negative electrode and arranged in a laminated manner at intervals.
A plurality of space forming members that form a plurality of spaces individually accommodating the plurality of cell members, and a plurality of space forming members.
Have,
The space forming member includes a substrate that covers at least one of the positive electrode side and the negative electrode side of the cell member, and a frame that surrounds the side surface of the cell member.
The cell member and the substrate of the space forming member are arranged in a state of being alternately laminated, and the adjacent frames are joined to each other.
The lead foil for the positive electrode and the lead foil for the negative electrode have a portion having a granular structure.
At least one of the interface between the lead foil for the positive electrode and the active material layer for the positive electrode and the interface between the lead foil for the negative electrode and the active material layer for the negative electrode has a portion formed in the granular structure and is described as ". The ten-point average roughness (RzJIS) according to the provisions of "Appendix JA of JIS B 0601: 2013" is 50 μm or more, and the maximum height roughness (Rz) according to the provisions is the average particle of the particles constituting the granular structure. Less than 1/2 of the diameter,
The substrate arranged between the adjacent cell members has a through hole extending in a direction intersecting the plate surface, and in the through hole, the lead foil for the positive electrode and the negative electrode of the adjacent cell member. A bipolar lead-acid battery in which a lead-acid battery is conductive and the plurality of cell members are electrically connected in series.

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