JP2022159906A - Bipolar storage battery and method of manufacturing bipolar storage battery - Google Patents

Abstract

To provide a bipolar storage battery and a method for manufacturing a bipolar storage battery that can surely prevent liquid leakage caused by the movement of an electrolytic solution from a positive electrode side to a negative electrode side through a through-hole provided to through a substrate while ensuring conduction between the positive electrode and the negative electrode, thereby maintaining performance of the storage battery, and extending service life thereof.SOLUTION: A bipolar storage battery includes a positive electrode 111, a negative electrode 112, and a separator 113 interposed between the positive electrode 111 and the negative electrode 112, and includes cell members 110 laminated and arranged at intervals, a space forming member 120 which forms a plurality of spaces for individually accommodating the plurality of cell members 110 and contain a substrate 121 which covers at least one of a positive electrode 111 side and a negative electrode 112 side of the cell members 110, a through-hole 121a provided through the substrate 121, and a conductor 180 which is inserted into the through-hole 121a to achieve conduction between the positive electrode side and the negative electrode side. A metal layer 150 is provided on the inner surface of the through-hole 112a and at least a surface of the conductor 180 facing the inner surface when the conductor 180 is inserted into the through-hole 112a.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to bipolar batteries and methods of manufacturing bipolar batteries.

In recent years, the number of power generation facilities using natural energy such as sunlight and wind power is increasing. In such power generation equipment, since the amount of power generation cannot be controlled, a storage battery is used to level the power load. That is, when the amount of power generation is greater than the amount of consumption, the storage battery is charged with the difference, and when the amount of power generation is less than the amount of consumption, the difference is discharged from the storage battery. As the storage battery described above, a lead-acid battery is often used from the viewpoint of economy, safety, and the like. As such a conventional lead-acid battery, for example, one described in Patent Document 1 below is known.

In the lead-acid battery described in Patent Document 1, a substrate (bipolar plate) made of resin is attached to the inside of a frame (rim) made of resin and having a picture frame shape. A positive electrode lead layer and a negative electrode lead layer are provided on one side and the other side of the substrate. The positive electrode lead layer is adjacent to the positive electrode active material layer. The negative electrode lead layer is adjacent to the negative electrode active material layer. A glass mat (electrolytic layer) containing an electrolytic solution is disposed inside the frame-shaped spacer made of resin. A plurality of frames and spacers are alternately laminated and assembled.

Furthermore, the positive electrode lead layer and the negative electrode lead layer are directly bonded inside the plurality of perforations formed in the substrate. That is, the lead-acid battery described in Patent Document 1 is a bipolar lead-acid battery in which a plurality of cell members and substrates having perforations (communication holes) for communicating between one surface and the other surface are alternately laminated. be. The cell member includes a positive electrode having a positive electrode lead layer provided with a positive electrode active material layer, a negative electrode having a negative electrode lead layer provided with a negative electrode active material layer, and an electrolytic layer interposed between the positive electrode and the negative electrode. The positive electrode lead layer of one cell member and the negative electrode lead layer of the other cell member are inserted into the perforations of the substrate and joined together, thereby connecting the cell members in series. It's becoming

Patent No. 6124894

However, if a structure such as that of the lead-acid battery disclosed in Patent Document 1 is adopted, the following phenomenon may occur. That is, in the case of the lead battery described in Patent Document 1, as shown in FIG. A positive electrode lead foil 220 is arranged, and a positive electrode active material layer (not shown) is arranged on the positive electrode lead foil 220 .

The lead foil to be adhered to the substrate using an adhesive includes positive electrode lead foil and negative electrode lead foil, and FIG. 15 illustrates the positive electrode lead foil as an example.

In the bipolar lead-acid battery as described above, the positive electrode lead foil 220 is corroded by the sulfuric acid contained in the electrolyte, and a corrosion product (lead oxide) film 260 is formed on the surface of the positive electrode lead foil 220. (see FIG. 15(b)). Then, there is a possibility that growth of the positive electrode lead foil 220 may occur due to the growth of the film 260 of the corrosion product.

In addition, the positive electrode lead foil 220 and the adhesive layer 240 are separated by this growth, and the electrolytic solution penetrates into the interface between the positive electrode lead foil 220 and the adhesive layer 240, and the corrosion of the positive electrode lead foil 220 by sulfuric acid further increases. There was a risk of progression (see (c) of FIG. 15). As a result, if the corrosion reaches the back surface of the positive electrode lead foil 220 (the surface facing the substrate 210), for example, a short circuit may occur and the performance of the battery may deteriorate.

Furthermore, when the electrolytic solution reaches the negative electrode side from the positive electrode side through the perforation (communication hole) that connects the one side and the other side, which is provided to achieve conduction between the positive electrode and the negative electrode, the so-called Liquid leakage occurs, resulting in deterioration of battery performance.

Therefore, various measures have been taken to prevent such leaks from occurring. For example, one of them is a method of manufacturing a substrate using so-called insert molding, in which a metal is placed in a perforated portion of a mold and the perimeter is covered with resin to mold a substrate in which a perforation is provided. . However, since the thickness of the substrate is thin, it is difficult to carry out insert molding while holding the metal.

In addition, a method of inserting a conductor into a hole and crimping the conductor by sandwiching it in the thickness direction of the board, or applying an adhesive to the inner circumference of the hole and applying pressure to insert the conductor into the hole A method of caulking or a method of caulking in addition to this method is also conceivable.

However, in the former case, even if crimped in the thickness direction in this way, the conductive body cannot be made to bite into the substrate in the perforation, and in the latter case, liquid leakage will eventually occur, and in either case, the Confidentiality could not be maintained.

The present invention ensures continuity between the positive electrode and the negative electrode, and reliably prevents liquid leakage caused by movement of the electrolyte from the positive electrode side to the negative electrode side through the through hole provided through the substrate. It is an object of the present invention to provide a bipolar storage battery and a method for manufacturing the bipolar storage battery, which can maintain the performance of the storage battery and extend the life of the storage battery.

A bipolar storage battery according to one aspect of the present invention includes a positive electrode having a positive electrode current collector and a positive electrode active material layer, a negative electrode having a negative electrode current collector and a negative electrode active material layer, and between the positive electrode and the negative electrode Spaced-apart stacked cell members with intervening separators and covering at least one of the positive and negative sides of the cell members forming a plurality of spaces for individually housing the plurality of cell members. a space forming member including a substrate and a frame surrounding the side surface of the cell member; a through hole provided through the substrate; , wherein the inner surface of the through hole and the surface of the conductor facing at least the inner surface when the conductor is inserted into the through hole are provided with a metal layer.

Further, in the method for manufacturing a bipolar storage battery according to one aspect of the present invention, the positive electrode assembly is provided in the through holes penetrating between one surface and the other surface of the substrate of the space forming member and between the one surface and the other surface. A step of providing a metal layer composed of a metal or alloy having a melting point lower than that of the metal or alloy constituting the current collector and the current collector for the negative electrode; A step of providing a metal layer on at least a surface of a conductor facing the through hole, inserting the conductor into the through hole, heating the conductor from the positive electrode side and the negative electrode side, and joining the conductor in the through hole a step of placing a positive electrode current collector on one surface; a step of placing a negative electrode current collector on the other surface; A positive electrode current collector is joined to one surface through a metal layer, and the negative electrode current collector is heated from the side of the arranged negative electrode current collector toward the substrate to attach the negative electrode current collector to the other surface of the substrate through the metal layer. and joining.

According to the present invention, a bipolar storage battery according to one aspect of the present invention includes a positive electrode having a positive electrode current collector and a positive electrode active material layer, a negative electrode having a negative electrode current collector and a negative electrode active material layer, and a positive electrode. a cell member having a separator interposed between the cell member and the negative electrode; a space forming member including a substrate covering at least one side and a frame surrounding the side surface of the cell member; a through hole provided through the substrate; a conductor for establishing electrical continuity, wherein the inner surface of the through hole and the surface of the conductor facing at least the inner surface when the conductor is inserted into the through hole are provided with a metal layer. By adopting such a configuration, the electrolyte moves from the positive electrode side to the negative electrode side through the through hole provided through the substrate while ensuring the conduction between the positive electrode and the negative electrode. It is possible to reliably prevent leakage, maintain the performance of the storage battery, and extend the life of the storage battery.

1 is a schematic cross-sectional view showing the outline of the structure of a bipolar storage battery according to an embodiment of the present invention; FIG. 1 is a flow chart showing a part of the manufacturing flow of a bipolar storage battery according to an embodiment of the present invention. FIG. 4A is a plan view and an AA line cut end view of a bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 4A is a plan view and an AA line cut end view of a bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 4A is a plan view and an AA line cut end view of a bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 4B is a cut end view of the bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 4B is a cut end view of the bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 4B is a cut end view of the bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 4B is a cut end view of the bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 4B is a cut end view of the bipolar plate in a part of the manufacturing process of the bipolar storage battery according to the embodiment of the present invention; FIG. 11 is an enlarged cut end view showing a first modification regarding the shape of the through hole and the conductive portion inserted into the through hole according to the embodiment of the present invention; FIG. 11 is an enlarged cut end view showing a second modified example of the shape of the through hole and the conductive portion inserted into the through hole according to the embodiment of the present invention; FIG. 11 is an enlarged cut end view showing a third modification regarding the shape of the through hole and the conductive portion inserted into the through hole according to the embodiment of the present invention; FIG. 11 is an enlarged cut end view showing a fourth modification regarding the shape of the through hole and the conductive portion inserted into the through hole according to the embodiment of the present invention; FIG. 11 is a diagram showing a conventional bipolar lead-acid battery in which the positive electrode lead foil grows due to corrosion due to sulfuric acid contained in the electrolyte, and as a result, the electrolyte penetrates into the interface between the positive electrode lead foil and the adhesive layer. be.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, each embodiment described below shows an example of the present invention. In addition, various modifications or improvements can be added to each of these embodiments, and forms to which such modifications or improvements are added can also be included in the present invention. Each of these embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof. In addition, below, a lead storage battery is mentioned as an example and demonstrated among various storage batteries.

〔overall structure〕
First, the overall configuration of a bipolar storage battery according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing the outline of the structure of a bipolar lead-acid battery 100 according to an embodiment of the invention.

As shown in FIG. 1, the bipolar lead-acid battery 100 of the first embodiment of the present invention includes a plurality of cell members 110, a plurality of bipolar plates (space forming members) 120, and a first end plate ( space forming member) 130 , a second end plate (space forming member) 140 and a cover plate 160 .

Here, although FIG. 1 shows the bipolar lead-acid battery 100 in which three cell members 110 are stacked, the number of cell members 110 is determined by battery design. Also, the number of bipolar plates 120 depends on the number of cell members 110 .

In the following, as shown in FIG. 1, the stacking direction of the cell members 110 is defined as the Z direction (vertical direction in FIG. 1), and the directions perpendicular to the Z direction and perpendicular to each other are defined as the X direction and the Y direction. do.

The cell member 110 includes a positive electrode 111 , a negative electrode 112 and a separator (electrolyte layer) 113 . The positive electrode 111 has a positive electrode lead foil 111a as a positive electrode current collector and a positive electrode active material layer 111b. The negative electrode 112 has a negative electrode lead foil 112a as a negative electrode current collector and a negative electrode active material layer 112b.

The separator 113 is impregnated with an electrolytic solution. Separator 113 is interposed between positive electrode 111 and negative electrode 112 . In the cell member 110, the positive electrode lead foil 111a, the positive electrode active material layer 111b, the separator 113, the negative electrode active material layer 112b, and the negative electrode lead foil 112a are laminated in this order.

The dimensions in the X direction and the Y direction of the positive electrode lead foil 111a are larger than the dimensions in the X direction and the Y direction of the positive electrode active material layer 111b. Similarly, the dimensions in the X direction and the Y direction of the negative electrode lead foil 112a are larger than the dimensions in the X direction and the Y direction of the negative electrode active material layer 112b. In addition, regarding the dimension (thickness) in the Z direction, the positive electrode lead foil 111a is larger (thicker) than 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. ).

A plurality of cell members 110 are stacked and arranged at intervals in the Z direction, and substrates 121 of bipolar plates 120 are arranged at the intervals. That is, the plurality of cell members 110 are stacked with the substrates 121 of the bipolar plates 120 sandwiched therebetween.

In this way, the plurality of bipolar plates 120, the first end plate 130, and the second end plate 140 form a space for forming a plurality of spaces (cells) C for individually accommodating the plurality of cell members 110. It is a member.

That is, the bipolar plate 120 covers both the positive electrode side and the negative electrode side of the cell member 110, and includes a substrate 121 having a rectangular planar shape and a frame 122 that surrounds the side surfaces of the cell member 110 and covers the four end surfaces of the substrate 121. And, it is a space forming member including.

In addition, as shown in FIG. 1, the bipolar plate 120 further includes pillars 123 protruding vertically from both sides of the substrate 121 . The number of pillars 123 protruding from each surface of the substrate 121 may be one or plural.

The substrate 121, the frame 122, and the pillars 123 that constitute the bipolar plate 120 are integrally formed of, for example, a thermoplastic resin. Examples of the thermoplastic resin forming the bipolar plate 120 include acrylonitrile-butadiene-styrene copolymer (ABS resin) and polypropylene. These thermoplastic resins are excellent in moldability and also in sulfuric acid resistance. Therefore, even if the electrolyte comes into contact with the bipolar plate 120, the bipolar plate 120 is unlikely to be decomposed, deteriorated, corroded, or the like.

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 projecting end faces of the pillars 123 is the same as the dimension of the frame 122 . By stacking the plurality of bipolar plates 120 with the frames 122 and the pillars 123 in contact with each other, a space C is formed between the substrates 121 and 121, and the pillars 123 in contact with each other The dimension of space C in the Z direction is preserved.

The positive electrode lead foil 111a, the positive electrode active material layer 111b, the negative electrode lead foil 112a, the negative electrode active material layer 112b, and the separator 113 have through holes 111c, 111d, 112c, 112d, and 113a through which the columnar portion 123 penetrates. formed respectively.

A substrate 121 of the bipolar plate 120 has a plurality of through holes 121a passing through the plate surface. A first concave portion 121b is formed on one surface of the substrate 121, and a second concave portion 121c is formed on the other surface. The depth of the first recess 121b is deeper than that of the second recess 121c. The X-direction and Y-direction dimensions of the first recess 121b and the second recess 121c correspond to the X- and Y-direction dimensions of the positive electrode lead foil 111a and the negative electrode lead foil 112a.

Substrates 121 of bipolar plates 120 are positioned between adjacent cell members 110 in the Z direction. In the first concave portion 121b of the substrate 121 of the bipolar plate 120, a positive electrode lead foil 111a, which is a positive electrode current collector made of lead or a lead alloy, is arranged. Further, a negative electrode lead foil 112a, which is a negative electrode current collector made of lead or a lead alloy, is arranged in the second concave portion 121c of the substrate 121 of the bipolar plate 120. As shown in FIG.

Specifically, the positive electrode lead foil 111a is joined to the first recessed portion 121b of the substrate 121 via a metal layer 150 provided between the first recessed portion 121b of the substrate 121 and the positive electrode lead foil 111a. . Further, the negative electrode lead foil 112a is joined to the second recess 121c of the substrate 121 via a metal layer 150 provided between the second recess 121c of the substrate 121 and the negative electrode lead foil 112a.

That is, in the embodiment of the present invention, the positive electrode lead foil 111a and the negative electrode lead foil 112a are heated to heat the metal layer between the substrate 121 and the positive electrode lead foil 111a and the negative electrode lead foil 112a. 150 is melted by the heat. As a result, the metal layer 150 and the positive electrode lead foil 111 a and the negative electrode lead foil 112 a are metal-bonded, and the positive electrode lead foil 111 a and the negative electrode lead foil 112 a are provided on the substrate 121 . Therefore, an adhesive is not used in joining the positive electrode lead foil 111a and the negative electrode lead foil 112a to the substrate 121 .

In this way, the positive electrode lead foil 111a and the negative electrode lead foil 112a are provided on the substrate 121 with the metal layer 150 interposed therebetween. , the substrate 121 is provided with a metal layer 150 .

Here, as described above, when the positive electrode lead foil 111a and the negative electrode lead foil 112a are joined to the substrate 121, due to the structure, the positive electrode lead foil 111a and the negative electrode lead foil 112a are directed toward the substrate 121 side. will be heated. Therefore, it is necessary to consider the possibility that the substrate 121 made of thermoplastic resin is affected by this heat. In addition, it is necessary to consider that the positive electrode lead foil 111a and the negative electrode lead foil 112a should not be affected by melting of the positive electrode lead foil 111a and the negative electrode lead foil 112a by heating.

Therefore, in the embodiment of the present invention, the substrate 121 is provided with two metal layers 150, ie, a first metal layer 150a and a second metal layer 150b. The first metal layer 150a covers the substrate 121 and serves as a base layer for the second metal layer 150b. The second metal layer 150b serves to connect the substrate 121 with the positive electrode lead foil 111a and the negative electrode lead foil 112a. Fulfill.

As described above, in the embodiment of the present invention, two metal layers, the first metal layer 150a and the second metal layer 150b, are provided as the metal layer 150. The number of layers to be provided can be set arbitrarily.

In view of the above, in the embodiment of the present invention, at least the second metal layer 150b is made of a metal having a melting point lower than that of lead or a lead alloy forming the positive electrode lead foil 111a and the negative electrode lead foil 112a. or an alloy.

That is, the melting point of the metal or alloy provided as the first metal layer 150a is higher than that of the second metal layer 150b, or the positive electrode lead foil 111a and the negative electrode lead foil 112a. The melting point of the metal or alloy provided as the metal layer 150b is lower than that of the first metal layer 150a, the positive electrode lead foil 111a, and the negative electrode lead foil 112a.

Specifically, as the first metal layer 150a provided to cover the substrate 121, nickel (Ni) can be employed. The melting point of nickel is approximately 1455°C. Meanwhile, tin (Sn) may be used as the second metal layer 150b that contacts the positive electrode lead foil 111a and the negative electrode lead foil 112a. The melting point of tin is approximately 232°C.

By using tin for the second metal layer 150b, when the positive electrode lead foil 111a and the negative electrode lead foil 112a are heated, the second metal layer 150b is melted by heating at a temperature at which tin melts. The positive electrode lead foil 111a and the negative electrode lead foil 112a can be bonded to the substrate 121 through the second metal layer 150b.

In addition, since the temperature for heating the positive electrode lead foil 111a and the negative electrode lead foil 112a is a temperature at which tin, which is the second metal layer 150b, is melted as described above, the positive electrode lead foil 111a and the negative electrode lead foil are heated. Neither does the foil 112a melt.

On the other hand, since the melting point of nickel constituting the first metal layer 150a as the base layer of the second metal layer 150b is higher than the melting point of tin of the second metal layer 150b, the lead foil 111a for the positive electrode and the lead foil for the negative electrode Even when the foil 112a is heated and bonded to the substrate 121, the foil 112a does not melt if heated to the temperature described above, and the influence of the heating on the substrate 121 can be avoided as much as possible.

It is also conceivable to use lead (Pb) instead of tin as described above for the second metal layer 150b. The positive electrode lead foil 111a and the negative electrode lead foil 112a are made of lead or a lead alloy. The ease of joining is taken into account. When this joining is performed, the heating temperature is set in consideration of the influence of heat on the positive electrode lead foil 111a and the negative electrode lead foil 112a.

The second metal layer 150b is made of lead (Pb) and similarly has a melting point lower than that of the first metal layer 150a, the positive electrode lead foil 111a and the negative electrode lead foil 112a. Indium (In) and bismuth (Bi) can also be used.

In providing the metal layer 150 on the substrate 121, for example, plating can be performed. However, as a method of providing the metal layer 150 on the substrate 121, various processes such as vapor deposition and etching can be adopted in addition to this plating process.

The region where the first metal layer 150a is provided is the entire region of the first concave portion 121b and the second concave portion 121c where the positive electrode lead foil 111a and the negative electrode lead foil 112a are provided. It is also provided on the inner surface of the through hole 121a.

Furthermore, although the above-described regions are mentioned here as the region where the first metal layer 150a is provided, the first metal layer 150a may be provided, for example, in the portion of the frame 122 of the bipolar plate 120. .

A second metal layer 150b is provided to cover the first metal layer 150a. Therefore, here, the second metal layer 150b is provided in the entire area of the first recess 121b and the second recess 121c where the first metal layer 150a is provided, and inside the through hole 121a.

A cover plate 160 for covering the outer edge of the positive electrode lead foil 111a is provided. As described above, in the embodiment of the present invention, the metal layer 150 composed of the first metal layer 150a and the second metal layer 150b is provided. It comes into direct contact with the electrolyte.

In this case, it is conceivable that the metal layer 150 may dissolve into the electrolytic solution, and if the metal layer 150 dissolves, dendrites may occur. In particular, if the dendrite grows and connects the positive electrode side and the negative electrode side, the possibility of short-circuiting between the two electrodes cannot be denied. In order to avoid such a phenomenon as much as possible, the cover plate 160 is provided on the outer edge of the positive electrode lead foil 111a.

The cover plate 160 is a thin plate-like frame and has a rectangular inner line and an outer line. The inner edge of the cover plate 160 overlaps the outer edge of the positive electrode lead foil 111 a , and the outer edge of the cover plate 160 overlaps the peripheral edge of the first recess 121 b on one surface of the substrate 121 .

That is, the rectangle forming the inner line of the cover plate 160 is smaller than the rectangle forming the outer line of the positive electrode active material layer 111b, and the rectangle forming the outer line of the cover plate 160 forms the opening surface of the first recess 121b. larger than a rectangle.

The metal layer 150 is arranged so as to extend from the end surface of the positive electrode lead foil 111a to the outer edge of the opening side of the first recess 121b. On the other hand, an adhesive 170 is placed between the inner edge of the cover plate 160 and the outer edge of the positive electrode lead foil 111 a and between the outer edge of the cover plate 160 and one surface of the substrate 121 .

That is, the cover plate 160 is fixed by the adhesive 170 across the peripheral edge of the first recess 121b on one surface of the substrate 121 and the outer edge of the positive electrode lead foil 111a. As a result, the outer edge of the positive electrode lead foil 111a is covered with the cover plate 160 even at the boundary with the edge of the first recess 121b.

Although not shown in FIG. 1, the outer edge of the negative electrode lead foil 112a may also be covered with a cover plate similar to the cover plate 160 that covers the outer edge of the positive electrode lead foil 111a. In addition, although the cover plate has been described as being a thin plate-like frame, it may be a tape-like object as long as it is resistant to electrolytic solution (sulfuric acid). .

Conductor 180 is arranged in through hole 121 a of substrate 121 of bipolar plate 120 . That is, the conductor 180 plays a role of sealing the through hole 121a by being inserted into the through hole 121a and heated. Furthermore, it also serves to electrically connect the positive electrode side and the negative electrode side by being joined to the positive electrode lead foil 111a and the negative electrode lead foil 112a, respectively.

Since the conductor 180 is inserted into the through hole 121a and seals the inside of the through hole 121a, the conductor 180 is formed in a shape that can be fitted into the through hole 121a.

That is, the conductor 180 has a surface facing the through-hole 121a when inserted into the through-hole 121a (hereinafter, such a surface is appropriately referred to as a “facing surface”) and both end surfaces of the surface. Configured. Therefore, when the conductor 180 is inserted into the through-hole 121a, both end surfaces of the conductor 180 are substantially flush with the surface forming the first recess 121b and the surface forming the second recess 121c of the substrate 121. configure.

The conductor 180 also has a metal layer 150 provided to the substrate 121 . Specifically, a metal layer having the same properties as the second metal layer 150b is provided on the surface of the conductor 180 by the above-described plating process or the like. Therefore, since the metal layer provided on the conductor 180 also uses a metal having the same properties as the second metal layer 150b provided on the substrate 121, the metal layer provided on the conductor 180 is also appropriately " second metal layer 150b”.

Note that the material of the conductor 180 itself is not particularly limited. For example, some metal may be used, or a material other than metal may be used. In the latter case, the second metal layer 150b can be provided on the surface of the conductor 180, although it may be necessary to provide the first metal layer 150a in order to provide the second metal layer 150b. Good if

Then, the conductor 180 provided with the second metal layer 150b is inserted into the through hole 121 and heated, whereby the second metal layer 150b of the conductor 180 and the second metal layer of the substrate 121 are separated. 150b are melted, and the conductor 180 is metal-bonded in the through hole 121a.

This ensures that the through hole 121a is sealed with metal. Therefore, even if the electrolytic solution leaks, it is possible to prevent liquid leakage in which the electrolytic solution moves from the positive electrode side to the negative electrode side.

In addition, when the conductor 180 is made of metal and the second metal layer 150b is provided so as to cover the metal, the conductor 180 inserted into the through-hole 121a and joined is connected to the positive electrode side. and the negative electrode side.

In the case of the conductor 180 configured by providing the second metal layer 150b on the surface of a material other than metal, the conductor 180 and the through-hole 121a are located at positions facing each other and are metal-bonded second metal layers. Conduction is achieved between the positive electrode side and the negative electrode side through the metal layer 150b.

As described above, the substrate 121 and the conductor 180 are provided with metal layers. Then, the conductor 180 is inserted into the through hole 121a of the substrate 121 and subjected to heat treatment. Furthermore, after the through hole 121a is sealed by the conductor 180, the positive electrode lead foil 111a and the negative electrode lead foil 112a are placed on the substrate 121, and heat treatment is performed again to form the positive electrode through the metal layer 150. The lead foil 111 a for the electrode or the lead foil 112 a for the negative electrode is metal-bonded to the substrate 121 .

When the conductor 180 is inserted into the through hole 121a and sealed, and when the positive electrode lead foil 111a and the negative electrode lead foil 112a are joined to the second metal layer 150b, the positive electrode lead foil 111a and the positive electrode lead foil 112a are bonded to the substrate 121. When the negative electrode lead foil 112a is provided, the positive electrode lead foil 111a and the negative electrode lead foil 112a are heated so as to be sandwiched toward the substrate 121 for metal bonding.

The heating temperature at this time is such that the second metal layer 150b, which has a lower melting point than the positive electrode lead foil 111a and the negative electrode lead foil 112a, melts. First, regarding the bonding between the conductor 180 and the through hole 121a, when heat is applied to the conductor 180, the second metal layer 150b covering the conductor 180 melts. If the heating is continued as it is, the second metal layer 150b provided in the through hole 121a continues to melt, thereby metallically joining the conductor 180 and the through hole 121a, and as a result, the through hole 121a is sealed.

Next, the positive electrode lead foil 111a and the negative electrode lead foil 112a are heat-treated to melt the second metal layer 150b provided in the entire regions of the first recess 121b and the second recess 121c. Then, the second metal layer 150b is joined to the positive electrode lead foil 111a and the negative electrode lead foil 112a, whereby the substrate 121 is provided with the positive electrode lead foil 111a and the negative electrode lead foil 112a.

In this manner, the conductor 180 is joined at the through hole 121a, and the positive electrode lead foil 111a and the negative electrode lead foil 112a are joined to the substrate 121, whereby the positive electrode lead foil 111a and the negative electrode lead foil 112a are electrically connected. connected 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 a space forming member including a substrate 131 covering the positive electrode side of the cell member 110 and a frame 132 surrounding the side surface of the cell member 110 . Further, a columnar portion 133 is provided that vertically protrudes from one surface of the substrate 131 (the surface of the bipolar plate 120 arranged on the most positive electrode side facing the substrate 121).

The planar shape of the substrate 131 is rectangular, and four end surfaces of the substrate 131 are covered with a frame 132, and the substrate 131, the frame 132, and the pillars 133 are integrally formed of, for example, the thermoplastic resin described above. . The number of pillars 133 protruding from one surface of substrate 131 may be one, or may be plural. number.

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 projecting end faces of the pillars 133 is the same as the dimension of the frame 132 . First end plate 130 is laminated with frame 132 and column 133 in contact with frame 122 and column 123 of bipolar plate 120 arranged on the outermost side (positive electrode side).

Thereby, a space C is formed between the substrate 121 of the bipolar plate 120 and the substrate 131 of the first end plate 130, and the columnar portion 123 of the bipolar plate 120 and the columnar portion 133 of the first endplate 130 are in contact with each other. , the dimension of the space C in the Z direction is maintained.

Through-holes 111c, 111d, and 113a through which the column portion 133 penetrates are formed in the positive electrode lead foil 111a, the positive electrode active material layer 111b, and the separator 113 of the cell member 110 arranged on the outermost side (positive electrode side). ing.

A concave portion 131 b is formed on one surface of the substrate 131 of the first end plate 130 . The X-direction and Y-direction dimensions of the recess 131b correspond to the X- and Y-direction dimensions of the positive electrode lead foil 111a.

In the concave portion 131b of the substrate 131 of the first end plate 130, the positive electrode lead foil 111a of the cell member 110 is arranged via the metal layer 150 as described above. In addition, similarly to the substrate 121 of the bipolar plate 120, the cover plate 160 is fixed to one side of the substrate 131 by the adhesive 170, and the outer edge of the positive lead foil 111a is even at the boundary with the peripheral edge of the recess 131b. It is covered with a cover plate 160 .

The first end plate 130 also includes a positive terminal (not shown in FIG. 1) electrically connected to the positive lead foil 111a in the recess 131b.

The second end plate 140 is a space forming member including a substrate 141 covering the negative electrode side of the cell member 110 and a frame 142 surrounding the side surface of the cell member 110 . Further, a pillar portion 143 is provided that vertically protrudes from one surface of the substrate 141 (the surface of the bipolar plate 120 arranged on the most negative electrode side facing the substrate 121).

The planar shape of the substrate 141 is rectangular, and four end surfaces of the substrate 141 are covered with a frame 142, and the substrate 141, the frame 142, and the pillars 143 are integrally formed of, for example, the thermoplastic resin described above. . The number of pillars 143 protruding from one surface of substrate 141 may be one, or may be plural. number.

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 projecting end faces of the two pillars 143 is the same as the dimension of the frame 142 . Second end plate 140 is laminated with frame 142 and column 143 in contact with frame 122 and column 123 of bipolar plate 120 arranged on the outermost side (negative electrode side).

Thereby, a space C is formed between the substrate 121 of the bipolar plate 120 and the substrate 141 of the second end plate 140, and the columnar portion 123 of the bipolar plate 120 and the columnar portion 143 of the second endplate 140 are in contact with each other. , the dimension of the space C in the Z direction is maintained.

Through-holes 112c, 112d, and 113a through which the column portion 143 penetrates are formed in the negative electrode lead foil 112a, the negative electrode active material layer 112b, and the separator 113 of the cell member 110 arranged on the outermost side (on the negative electrode side), respectively. ing.

A concave portion 141 b is formed on one surface of the substrate 141 of the second end plate 140 . The X-direction and Y-direction dimensions of the recess 141b correspond to the X- and Y-direction dimensions of the negative electrode lead foil 112a.

The negative electrode lead foil 112 a of the cell member 110 is arranged in the concave portion 141 b of the substrate 141 of the second end plate 140 with the metal layer 150 interposed therebetween. The second end plate 140 also includes a negative terminal (not shown in FIG. 1) electrically connected to the negative lead foil 112a in the recess 141b.

Here, when joining the adjacent bipolar plates 120, the first end plate 130 and the adjacent bipolar plate 120, or the second end plate 140 and the adjacent bipolar plate 120, for example, vibration welding, Various welding methods such as ultrasonic welding and hot plate welding can be employed. Of these, vibration welding is performed by vibrating surfaces to be welded while pressurizing them during welding, and the welding cycle is fast and reproducibility is good. Therefore, vibration welding is more preferably used.

It should be noted that not only the frame bodies arranged at opposite positions in the bipolar plate 120, the first end plate 130, and the second end plate 140 adjacent to each other but also each column part are included as objects to be welded.

Although not shown in the drawing, one of the four end faces of the frame has a cutout portion that forms an injection hole for filling the space C with the electrolytic solution. For example, when the notch is formed on the side surface of the frame on the right side of the drawing, the notch penetrates the frame in the X direction and has a semicircular recessed shape from both end surfaces of the frame in the Z direction. This cutout portion does not participate in the above-described joint structure, and when the above-mentioned joint structure is formed by vibration welding, a circular injection hole is formed by the opposing cutout portions.

〔Production method〕
The bipolar lead-acid battery 100 of this embodiment can be manufactured, for example, by a method including steps described below. Here, the manufacturing process of the bipolar lead-acid battery 100 will be described with reference to FIGS. 2 to 10 as appropriate.

<Manufacturing process of bipolar plate with lead foil for positive and negative electrodes>
FIG. 2 is a flowchart showing a part of the manufacturing flow of the bipolar lead-acid battery 100 according to the embodiment of the present invention. That is, the manufacturing process shown in FIG. 2 particularly shows the flow of manufacturing the bipolar plate with the positive electrode lead foil 111a and the negative electrode lead foil 112a.

3 to 10 are plan views or cross-sectional end views of bipolar plate 120 taken along line AA in part of the manufacturing process of bipolar lead-acid battery 100 according to the embodiment of the present invention. Here, in FIGS. 3 to 5, the top plan view is shown in the upper stage, and the AA line cut end view is shown in the lower stage. 6 to 10 show cut end views showing states cut along line AA in the plan view shown in FIG. 3 and the like.

3 to 5, one surface on which the positive electrode lead foil 111a is provided is shown in plan view. 3 to 10, the upper side of the drawing corresponds to one surface, and the positive electrode lead foil 111a is provided on this one surface. On the other hand, the lower side of the drawing corresponds to the other surface, and the negative electrode lead foil 112a is provided on this other surface.

Further, a column portion 123 is provided substantially at the center of the substrate 121 of the bipolar plate 120 shown in the plan views of FIGS. Further, a through hole 121a is provided so as to surround the column portion 123 and penetrate one surface on the positive electrode side and the other surface on the negative electrode side. However, the arrangement position, arrangement number, and diameter of the pillars 123 and the through holes 121a can be set arbitrarily.

As shown in the flow chart of FIG. 2, first, a first metal is applied to both surfaces of the substrate 121 of the bipolar plate 120, which are one surface and the other surface, and the through holes 121a penetrating between the one surface and the other surface. A layer 150a is provided (ST1). As described above, nickel, for example, is used as the metal forming the first metal layer 150a in the embodiment of the present invention.

Nickel is provided on the surface of the substrate 121 by plating or the like. Specifically, plating is applied to the entire area of the first recess 121b and the second recess 121c and the through hole 121a, which are the areas where the positive electrode lead foil 111a and the negative electrode lead foil 112a are provided. .

FIG. 3 shows the bipolar plate 120 before the first metal layer 150a is applied. At this point, the substrate 121 itself made of a thermoplastic resin such as ABS resin is shown without being plated.

On the other hand, substrate 121 of bipolar plate 120 shown in FIG. Further, as shown in the AA line cut end view, the first metal layer 150a is also provided in the through hole 121a.

Next, a second metal layer 150b is provided so as to cover the entire regions of the first and second recesses 121b and 121c and the first metal layer 150a provided in the through hole 121a (ST2). Looking at this state with the bipolar plate 120 shown in FIG. 5, as shown in the plan view, the second metal layer 150b is provided by plating except for the pillars 123. As shown in FIG. Further, as shown in the AA cut end view, the second metal layer 150b is provided so as to cover the first metal layer 150a also in the through hole 121a.

Through steps ST1 and ST2, the bipolar plate 120 for joining the positive electrode lead foil 111a and the negative electrode lead foil 112a is completed. The process of providing such a metal layer 150 is also performed on the conductor 180 .

That is, the second metal layer 150b is also provided for the conductor 180 using the same metal used for providing the second metal layer 150b for the substrate 121 (ST3). Here, when covering the conductor 180, the same metal as the second metal layer 150b in the substrate 121 is used because the conductor 180 is inserted into the through-hole 121a to be joined, and This is because, after bonding the hole 121a, the conditions for bonding such as the setting of the heating temperature are made as uniform as possible when bonding the positive electrode lead foil 111a and the negative electrode lead foil 112a.

In the cut end view shown in FIG. 6, the conductor 180 is shown above the substrate 121 and directly above the through hole 121a. Since there are three through-holes 121a provided in the substrate 121 here, three conductors 180 are also prepared according to this number.

Both the substrate 121 and the conductor 180 are covered with the second metal layer 150b. Further, here, for the conductor 180, only one metal layer is provided using the same metal as the second metal layer 150b. As for the material of the conductor 180 itself covered with the second metal layer 150b, various materials such as metal or resin can be freely selected and used as described above.

Although the metal layer 150 is provided in the order of the substrate 121 and the conductor 180 so far, for the sake of convenience of explanation, the metal layer 150 is provided on the substrate 121 and the conductor 180. The order is not limited to this order.

Thus, the substrate 121 having the metal layer 150 and the conductor 180 are prepared, and the conductor 180 is inserted so as to fit into the through hole 121a (ST4). That is, as shown in FIG. 7 from the state of FIG. 6, the conductor 180 is fitted into the through hole 121a. Here, in order to show that the conductor 180 is inserted into the through hole 121a, FIG. 7 shows a downward arrow indicating insertion from one surface side. It may be performed from either the face side or the other face side.

By inserting the conductor 180 into the through-hole 121a, the second metal layer 150b provided in the through-hole 121a and the second metal layer 150b provided on the opposite surface of the conductor 180 arranged at a position facing each other. contact with the metal layer 150b. Further, the second metal layer 150b continuous from the facing surface of the conductor 180 to both end surfaces is the second metal layer 150b provided on the surface forming the first recess 121b and the surface forming the second recess 121c of the substrate 121. of the metal layer 150b.

In this state, the heating device 190A is brought into contact with the conductor 180 to heat the conductor 180 (ST5). At this time, as shown in the cut end view of FIG. 8, the heating device 190A is brought into contact with the conductor 180 so as to sandwich it from both the positive electrode side and the negative electrode side, and the conductor 180 is heated. By heating the conductor 180, the second metal layer 150b covering the conductor 180 melts.

It should be noted that the conductor 180 can be pressurized at the same time that the conductor 180 is subjected to heat treatment using the heating device 190A. However, if the pressure is excessively applied, the conductor 180 may be deformed inside the through hole 121a, and the melted second metal layer 150b may leak out of the through hole 121a. Therefore, when pressurizing, the pressure to be applied is adjusted in consideration of this point.

Then, as the second metal layer 150b of the conductor 180 melts, the heat of the heating device 190A is also transmitted to the second metal layer 150b of the through hole 121a that contacts the opposite surface of the conductor 180, and the through hole The second metal layer 150b of 121a is also melted. In this way, in the through hole 121a, the second metal layer 150b of the conductor 180 and the second metal layer 150b of the substrate 121 are melted by heating, so that they are metal-bonded to form the substrate 121 and the conductor 180. and become one.

Note that when the heat treatment is performed, the entire region of the second metal layer 150b provided in the first concave portion 121b and the second concave portion 121c of the substrate 121 may be heated.

In addition, the second metal layer 150b provided on both end surfaces of the conductor 180 is also melted by the heat treatment, and the heat applied to the both end surfaces is applied to the first concave portion 121b and the second concave portion 121c of the substrate 121. The second metal layer 150b is also melted. Therefore, the second metal layer 150b continuing from the opposing surface of the conductor 180 to both end surfaces and the second metal layers 150b provided in the first and second recesses 121b and 121c are metal-bonded.

By the heat treatment described above, the conductor 180 and the substrate 121 in the through-hole 121a are metal-bonded, so that the through-hole 121a is sealed in an airtight state. In addition, since both end faces of the conductor 180 are also metal-bonded to the first recess 121b and the second recess 121c, the through hole 121a is not connected to the conductor 180 in the regions of the first recess 121b and the second recess 121c. are closed by and constitute approximately the same plane.

Next, a process for joining the positive electrode lead foil 111a and the negative electrode lead foil 112a to the substrate 121 is started (ST6). Specifically, first, the bipolar plate 120 is placed on a workbench with the first concave portion 121b side of the substrate 121 facing upward. Then, the positive electrode lead foil 111a is arranged in the first concave portion 121b. At this time, the column portion 123 of the bipolar plate 120 is passed through the through hole 111c of the positive electrode lead foil 111a.

Next, the substrate 121 is placed on a workbench with the second concave portion 121c facing upward, and the negative electrode lead foil 112a is arranged in the second concave portion 121c. At this time, the column portion 123 of the bipolar plate 120 is passed through the through hole 112c of the negative electrode lead foil 112a.

FIG. 9 shows this state. As shown in the cut end view of FIG. 9, the positive lead foil 111a is placed on the second metal layer 150b on one side of the substrate 121. As shown in FIG. On the other hand, the negative electrode lead foil 112a is arranged on the second metal layer 150b on the other side.

Then, in this state, heat is applied from the positive electrode side and the negative electrode side toward the substrate 121 side so as to sandwich the positive electrode lead foil 111a and the negative electrode lead foil 112a (ST7). In FIG. 10, the heating device 190B is arranged on both sides of the surface on which the positive electrode lead foil 111a is provided and the surface on which the negative electrode lead foil 112a is provided, and moves so as to sandwich the substrate 121 as indicated by the arrows. The lead foil 111a and the negative electrode lead foil 112a are heated.

In addition, in the above-described step of heating from the positive electrode side and the negative electrode side toward the substrate 121 side, heating may be performed simultaneously from the positive electrode side and the negative electrode side so as to sandwich the substrate 121, or after heating one side. , the other side may also be heated.

The heat from the heating device 190B melts the first and second recesses 121b and 121c of the substrate 121 and the second metal layer 150b on both end surfaces of the conductor 180. FIG. As a result, the positive electrode lead foil 111 a and the negative electrode lead foil 112 a are joined to the substrate 121 via the metal layer 150 .

By heating the positive electrode lead foil 111a and the negative electrode lead foil 112a in this manner, the second metal layer 150b is melted. This is because the lead foil 111a and the negative electrode lead foil 112a are made of, for example, tin, which has a lower melting point than the metal.

Further, by being heated in this manner, the positive electrode lead foil 111a, the conductor 180, and the negative electrode lead foil 112a are joined to each other through the second metal layer 150b. It becomes electrically conductive.

Next, the substrate 121 is placed on a workbench with the first concave portion 121b side facing upward, and an adhesive is applied to the outer edge portion of the positive electrode lead foil 111a and the upper surface of the substrate 121, which will be the edge portion of the first concave portion 121b. 170 is applied, the cover plate 160 is placed thereon, and the adhesive 170 is cured. As a result, the cover plate 160 is fixed over the outer edge of the positive electrode lead foil 111a and over the portion of the substrate 121 (peripheral edge of the first recess 121b) that continues to the outside thereof.

Through the steps described above, the bipolar plate 120 with lead foils for positive and negative electrodes is obtained. A necessary number of bipolar plates 120 with lead foils for positive and negative electrodes are prepared.

Regarding the step of bonding the positive electrode lead foil 111a and the negative electrode lead foil 112a to the second metal layer 150b on the substrate 121, here, the heating device 190B is arranged on the positive electrode side and the negative electrode side, and the substrate 121 is heated. An example of heating from both sides toward . However, instead of such a process, after joining the positive electrode lead foil 111a and the second metal layer 150b, the substrate 121 is turned over and the negative electrode lead foil 112a and the second metal layer 150b are joined again. You can do it.

In addition, in the step of heating the substrate 121 from the positive electrode side and the negative electrode side as described above, pressure is simultaneously applied from the positive electrode lead foil 111a and the negative electrode lead foil 112a toward the substrate 121 with a preset force. can be

<Manufacturing process of end plate with lead foil for positive electrode>
The process of providing the first metal layer 150 a and the second metal layer 150 b performed on the substrate 121 of the bipolar plate 120 described above is also performed on the substrate 131 of the first end plate 130 . After the recess 131b is provided with the second metal layer 150b, the substrate 131 of the first end plate 130 is placed on a workbench with the recess 131b facing up.

The positive electrode lead foil 111a is arranged in the recess 131b while the column portion 133 of the end plate 130 is passed through the through hole 111c of the positive electrode lead foil 111a. Then, the positive electrode lead foil 111a is heated by the heating device 190B and bonded to the second metal layer 150b, and the positive electrode lead foil 111a is provided on one surface of the substrate 131. FIG.

Next, an adhesive 170 is applied to the outer edge of the positive electrode lead foil 111a and the upper surface of the substrate 131, which is the edge of the recess 131b, and the cover plate 160 is placed thereon to cure the adhesive 170. As a result, the cover plate 160 is fixed over the outer edge of the positive electrode lead foil 111a and over the portion of the substrate 131 continuing to the outside thereof. This obtains the end plate with the lead foil for positive electrodes.

<Manufacturing process of end plate with lead foil for negative electrode>
As with the first end plate 130, after the metal layer 150b is provided in the recess 141b of the substrate 141, the substrate 141 of the second end plate 140 is placed on a workbench with the recess 141b facing up. The negative electrode lead foil 112a is arranged in the concave portion 141b while the column portion 143 of the second end plate 140 is passed through the through hole 112c of the negative electrode lead foil 112a. Then, while heating the negative electrode lead foil 112a using the heating device 190B, it is bonded to the second metal layer 150b to form the second end plate 140 in which the negative electrode lead foil 112a is provided on one surface of the substrate 141. get

<Step of laminating and joining plates>
First, the first end plate 130 to which the positive electrode lead foil 111a and the cover plate 160 are fixed is placed on a workbench with the positive electrode lead foil 111a facing upward. and placed on the positive electrode lead foil 111a. At this time, the columnar portion 133 of the first end plate 130 is passed through the through hole 111d of the positive electrode active material layer 111b. Next, the separator 113 and the negative electrode active material layer 112b are placed on the positive electrode active material layer 111b.

Next, on the first end plate 130 in this state, the negative electrode lead foil 112a side of the bipolar plate 120 with the positive and negative lead foils is placed downward. At that time, the columnar portion 123 of the bipolar plate 120 is passed through the through hole 113a of the separator 113 and the through hole 112d of the negative electrode active material layer 112b, and placed on the columnar portion 133 of the first end plate 130, The frame 122 of the bipolar plate 120 is placed on the frame 132 of the first end plate 130 .

In this state, the first end plate 130 is fixed, and vibration welding is performed while vibrating the bipolar plate 120 in the diagonal direction of the substrate 121 . Thereby, the frame 122 of the bipolar plate 120 is joined onto the frame 132 of the first end plate 130, and the column 123 of the bipolar plate 120 is joined onto the column 133 of the first end plate 130. be done.

As a result, the bipolar plate 120 is joined on the first end plate 130 , the cell member 110 is arranged in the space C formed by the first end plate 130 and the bipolar plate 120 , and the upper surface of the bipolar plate 120 is The positive electrode lead foil 111a is exposed.

Next, the positive electrode active material layer 111b, the separator 113, and the negative electrode active material layer are placed on the thus-obtained assembly in which the bipolar plate 120 is bonded onto the first end plate 130. 112b are placed in this order, another bipolar plate 120 with positive and negative lead foils is placed with the negative lead foil 112a facing downward.

In this state, this combined body is fixed, and vibration welding is performed while vibrating another bipolar plate 120 with lead foils for positive and negative electrodes in the diagonal direction of the substrate 121 . This vibration welding process is continued until the required number of bipolar plates 120 are bonded onto the first end plate 130 .

Finally, after placing the positive electrode active material layer 111b, the separator 113, and the negative electrode active material layer 112b in this order on the uppermost bipolar plate 120 of the assembly in which all the bipolar plates 120 are joined, , the second end plate 140 is placed with the negative lead foil 112a side facing downward.

In this state, the combined body is fixed, and vibration welding is performed while vibrating the second end plate 140 in the diagonal direction of the substrate 141 . As a result, the second end plate 140 is joined on the uppermost bipolar plate 120 of the combined body in which all the bipolar plates 120 are joined.

<Liquid injection and formation process>
In the step of stacking and joining the plates described above, a joining structure is formed by vibration welding of the opposing surfaces of the frames, and the notches of the opposing frames form one end surface of the bipolar lead-acid battery 100, for example, in the X direction. A circular injection hole is formed at each space C of . A predetermined amount of electrolytic solution is injected into each space C through the injection hole, and the separator 113 is impregnated with the electrolytic solution. Then, the bipolar lead-acid battery 100 can be manufactured by forming under predetermined conditions.

As described above, the injection hole may be formed by providing a notch portion in the frame in advance, or may be opened using a drill or the like after the frame is joined.

As described above, the substrate 121 of the bipolar plate 120 is provided with a metal layer including the through holes 121a, and the conductors 180 are also provided with a metal layer and then fitted into the through holes 121a to be joined together. As a result, while ensuring continuity between the positive electrode and the negative electrode, it is possible to reliably prevent liquid leakage caused by movement of the electrolyte from the positive electrode side to the negative electrode side through the through hole provided through the substrate. Therefore, it is possible to provide a bipolar storage battery and a method for manufacturing such a bipolar storage battery, which can maintain the performance of the storage battery and extend the life of the storage battery.

In addition, in the embodiment of the present invention described above, the substrate is covered as part of the metal layer, and the first metal layer is provided as the base layer for the second metal layer. If it is possible to directly provide a metal layer that plays a role, it is possible to omit the step of providing the first metal layer.

Furthermore, in the description so far, it is assumed that the second metal layer provided on the substrate is provided on the entire surface of the first recess and the second recess together with the through holes. However, the second metal layer is not provided on the entire surface of the first recess and the second recess, but only on the inner surface of the through hole and the first recess and the second recess in the vicinity of the through hole, for example. It is also possible to provide

The description so far has been made on the assumption that the through hole 121a is formed in a cylindrical shape, and the conductor 180 is formed in a rectangular cross-sectional shape so as to match this shape. However, the shapes of both of them are not limited to these shapes, and any shape can be used as long as the through hole 121a passing through the positive electrode side and the negative electrode side is reliably sealed by the conductor 180. may be adopted.

11 to 14, modified examples of the through hole 121a and the conductor 180 in the bipolar lead-acid battery 100 described above will be described below. In FIGS. 11 to 14, illustration of parts other than the through holes and conductors is omitted. It has also been explained that the through hole is provided with the first metal layer 150a and the second metal layer 150b, and that the conductor is provided with the second metal layer 150b. Street.

FIG. 11 is an enlarged cut end view showing a first modification regarding the shape of through hole 121A and conductor 180A inserted into through hole 121A according to the embodiment of the present invention. A through hole 121A shown in FIG. 11 is formed in a tapered shape from one surface of the substrate 121, which is the positive electrode side, toward the other surface, which is the negative electrode side. In accordance with the shape of the through hole 121A, the conductor 180A is formed so that the end face on the positive electrode side of the two end faces has a larger area than the end face on the negative electrode side, and has a substantially trapezoidal cross-sectional shape. is formed in

Next, FIG. 12 is an enlarged cut end view showing a second modification regarding the shape of through hole 121B and conductor 180B inserted into through hole 121B according to the embodiment of the present invention. A through hole 121B shown in FIG. 12 is provided with a convex portion 121Ba in the circumferential direction of the through hole 121B. Further, since the protrusion 121Ba is provided on the negative electrode side, the opening of the through hole 121B is wider on the positive electrode side than on the negative electrode side.

In addition, due to the shape of the through hole 121B, the conductive body 180B is formed such that the end face on the positive electrode side is larger than the end face on the negative electrode side. In order to maintain airtightness when the through hole 121B is fitted and sealed, the conductor 180B is provided with a step corresponding to the position of the projection 121Ba on the opposing surface thereof.

The first and second modifications shown in FIGS. 11 and 12 each have a shape in which the end surface of the conductor on the positive electrode side has a larger area than the end surface on the negative electrode side. described as a thing. However, it goes without saying that the shape of the conductor may conversely be such that the end face on the negative electrode side has a larger area than the end face on the positive electrode side.

FIG. 13 is an enlarged cut end view showing a third modification regarding the shape of through hole 121C and conductor 180C inserted into through hole 121C according to the embodiment of the present invention. In other words, in the third modification, similarly to the second modification, a protrusion is provided in the circumferential direction inside the through hole 121C. However, the convex portion 121Ca is provided in the through hole 121C substantially at the center in the thickness direction of the substrate 121, and is formed so as to taper from the positive electrode side and the negative electrode side.

Therefore, the conductor 180C in the third modification is formed so that one of the two end faces has a larger area than the other end face in accordance with the shape of the through hole 121C. It is formed in a substantially trapezoidal shape. Two such conductors 180C are prepared, and the conductors 180C are inserted into the through holes 121a by fitting them into the through holes 121C from the positive electrode side and the negative electrode side, respectively.

FIG. 14 is an enlarged cut end view showing a fourth modification regarding the shape of through hole 121D and conductor 180D inserted into through hole 121D according to the embodiment of the present invention. In the fourth modification, as shown in the third modification, the protrusion 121Da is provided in the circumferential direction inside the through-hole 121D and approximately in the center of the substrate 121 in the thickness direction.

Therefore, in the through hole 121D, the opening on the positive electrode side and the opening on the negative electrode side have the same size, but the opening at the convex portion 121Da is formed to be smaller than the openings on the positive electrode side and the negative electrode side. ing.

Also, due to the shape of the through hole 121D, the conductor 180D is formed in a convex shape as shown in FIG. In order to maintain airtightness when the through hole 121D is fitted and sealed, the conductor 180D is provided with a step corresponding to the position of the projection 121Da on the opposing surface thereof.

Even in the combinations of the through holes and the conductors in the above first to fourth modifications, the metal layers provided by the heat treatment are melted and bonded to each other, so that the through holes are hermetically sealed. can be sealed to Accordingly, it is possible to reliably prevent liquid leakage from the positive electrode side to the negative electrode side.

In addition, by using the through holes having the shapes shown in FIGS. 11 to 14 and conductors matching the shape of the through holes, even if the electrolytic solution enters the through holes, It is possible to sufficiently secure the distance from the positive electrode side to the negative electrode side, that is, the so-called creepage distance. Therefore, it is possible to delay the time for the electrolyte solution to reach the negative electrode side from the positive electrode side, so that the battery performance can be maintained and the life of the battery can be extended accordingly.

As described above, the bipolar lead-acid battery has been described as an example in the embodiments of the present invention. However, if the above description applies to other storage batteries that use other metals (e.g., aluminum, copper, nickel), alloys, and conductive resins instead of lead for the current collector plate, the application is naturally excluded. not something to do.

DESCRIPTION OF SYMBOLS 100... Bipolar lead acid battery 110... Cell member 111... Positive electrode 112... Negative electrode 111a... Lead foil for positive electrode 112a... Lead foil for negative electrode 111b... Active material layer for positive electrode 112b Negative electrode active material layer 113 Separator 120 Bipolar plate 121 Bipolar plate substrate 121a Substrate through hole 122 Bipolar plate frame 130 First end plate 131 first end plate substrate 132 first end plate frame 140 second end plate 141 second end plate substrate 142 Frame body of second end plate 150 Metal layer 150a First metal layer 150b Second metal layer 160 Cover plate 170 Adhesive C Cell ( space for accommodating cell members)

Claims (13)

A positive electrode having a positive electrode current collector and a positive electrode active material layer, a negative electrode having a negative electrode current collector and a negative electrode active material layer, and a separator interposed between the positive electrode and the negative electrode are provided with a space therebetween. a cell member arranged in a stack;
a substrate covering at least one of the positive electrode side and the negative electrode side of the cell member and forming a plurality of spaces for individually accommodating the plurality of cell members; and a frame surrounding the side surface of the cell member. a space-forming member including;
a through hole provided through the substrate;
a conductor that is inserted into the through-hole and establishes electrical continuity between the positive electrode side and the negative electrode side;
A bipolar storage battery, wherein an inner surface of the through hole and at least a surface of the conductor facing the inner surface when the conductor is inserted into the through hole are provided with a metal layer. 2. The metal layer according to claim 1, wherein the metal layer is made of a metal or alloy having a melting point lower than that of the metal or alloy constituting the positive electrode current collector and the negative electrode current collector. Bipolar storage battery. 3. The bipolar storage battery according to claim 1, wherein the metal layers provided in the through-hole and the conductor, wherein the metal layers facing each other are made of the same material. 4. The method according to any one of claims 1 to 3, wherein the metal layer provided in the through hole comprises a first metal layer in contact with the substrate and a second metal layer provided to cover the first metal layer. A bipolar storage battery according to any one of the above. The melting point of the metal or alloy provided as the first metal layer is higher than that of the second metal layer, the positive electrode current collector, and the negative electrode current collector. 5. The method according to claim 4, wherein the melting point of the metal or alloy provided as the layer is lower than that of the first metal layer, the positive electrode current collector, and the negative electrode current collector. Bipolar storage battery. 6. The bipolar storage battery according to claim 1, wherein said metal layer is provided by plating. 7. The bipolar storage battery according to any one of claims 1 to 6, wherein an inner surface of said through hole is provided with a convex portion in a circumferential direction. 8. The bipolar storage battery according to claim 1, wherein the positive electrode current collector and the negative electrode current collector are made of lead or a lead alloy. A metal or alloy forming a positive electrode current collector and a negative electrode current collector in a through hole penetrating between one surface and the other surface of the substrate of the space forming member and between the one surface and the other surface. providing a metal layer composed of a metal or alloy with a melting point lower than the melting point of
a step of providing the metal layer on at least a surface facing the through-hole, which is a conductor inserted into the through-hole to achieve conduction between the positive electrode side and the negative electrode side;
a step of inserting the conductor into the through hole, heating the conductor from the positive electrode side and the negative electrode side, and joining the conductor in the through hole;
disposing the positive electrode current collector on the one surface;
disposing the negative electrode current collector on the other surface;
a step of heating from the arranged positive electrode current collector side toward the substrate to bond the positive electrode current collector to the one surface of the substrate via the metal layer;
a step of heating from the arranged negative electrode current collector side toward the substrate to bond the negative electrode current collector to the other surface of the substrate via the metal layer;
A method for manufacturing a bipolar storage battery, comprising: The step of providing the metal layer on the substrate includes:
providing a first metal layer on the one surface, the other surface, and the through hole;
providing a second metal layer overlying the first metal layer;
10. The method of manufacturing a bipolar storage battery according to claim 9, comprising: The melting point of the second metal layer is lower than the melting point of the first metal layer and lower than the melting points of the metals or alloys forming the positive electrode current collector and the negative electrode current collector. 11. The method of manufacturing a bipolar storage battery according to claim 10. 12. The method of manufacturing a bipolar storage battery according to claim 11, wherein the metal layer provided on the conductor is the second metal layer. 13. The method of manufacturing a bipolar storage battery according to any one of claims 9 to 12, wherein the metal layer is provided by plating.

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