Bipolar storage battery

Abstract

To prevent a manufacturing defect due to a member protruding from a space forming member by adopting the space forming member capable of reducing an amount of the member protruding from a frame body disposed at a peripheral part of a substrate in a stacking direction even when the member such as a current collector and an active material layer are disposed on the substrate in manufacturing.SOLUTION: A bipolar storage battery includes: a plurality of cell members 110; and a plurality of space forming members 120 that form spaces for individually housing the plurality of cell members 110. The space forming members 120 include a substrate 121 and a frame body 122. A first distance PL1 from a first surface of the substrate 121 on the side where a positive electrode current collector 111a is provided to a first bonding surface 122a of the frame body 122 is different from a second distance PL2 from a second surface of the substrate 121 on the side where a negative electrode current collector 112a is provided to a second bonding surface 122b of the frame body 122 when bonding surfaces of adjacent frame bodies 122 which are alternately stacked through the substrate 121 of the space forming members 120 are bonded to each other.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a bipolar storage battery. [Background technology]

[0002] In recent years, the number of power generation facilities that utilize natural energy sources such as solar and wind power has been increasing. Since it is not possible to control the amount of power generated in such power generation facilities, storage batteries are used to level the power load. That is, when the amount of power generated is greater than the amount consumed, the difference is charged to the storage battery, and when the amount of power generated is less than the amount consumed, the difference is discharged from the storage battery. Lead-acid batteries are widely used as the storage batteries from the viewpoints of economy, safety, and the like. For example, the following Patent Document 1 describes a known example of such a conventional lead-acid battery.

[0003] In the lead-acid battery described in Patent Document 1, a substrate made of resin is attached to the inside of a picture-frame-shaped frame (rim) made of resin, and the substrate is attached at a position that is approximately the center of the frame in the stacking direction.

[0004] A positive electrode current collector and a negative electrode current collector are provided on one and the other sides of the substrate. A positive electrode active material layer is adjacent to the positive electrode current collector. A negative electrode active material layer is adjacent to the negative electrode current collector. These components together form a bipolar electrode plate. A glass mat (electrolytic layer) containing an electrolyte is disposed inside a frame-shaped resin spacer. Multiple frames and spacers are alternately stacked and assembled.

[0005] Furthermore, the positive electrode lead layer and the negative electrode lead layer are directly bonded inside a 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 substrates having perforations (communicating holes) connecting one side to the other side and cell members are alternately stacked in multiple layers. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6124894 Summary of the Invention [Problem to be solved by the invention]

[0007] In such a lead-acid battery, when the substrate is attached to the inside of the frame as described above, it is positioned approximately in the center of the stacking direction. Then, in the manufacturing process, a current collector, an active material layer, an electrolytic layer (separator), etc. are sequentially provided on the substrate. Specifically, these components are sequentially stacked on the substrate, and as a result of the stacking, the height of each component in the stacking direction may be greater than the height of the frame arranged outside the substrate in the stacking direction. In other words, after stacking, a portion of the components protrudes from the frame.

[0008] If the components are stacked and protrude from the frame, it is possible that the positions of the components that are in contact with each other will become misaligned. If the misaligned components are positioned so that they protrude from the frame or spacer, for example, joining them in this state may result in, for example, an undesired join and may result in assembly defects.

[0009] The present invention aims to provide a bipolar storage battery that can prevent manufacturing defects caused by components protruding from the space-forming member by employing a space-forming member that can reduce the amount by which each component protrudes from a frame placed on the peripheral edge of the substrate in the stacking direction, even when each component, such as a current collector or an active material layer, is placed on the substrate during manufacturing. [Means for solving the problem]

[0010] A bipolar storage battery according to one embodiment of the present invention comprises a plurality of cell members each including 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, and a plurality of space-forming members that form spaces to individually accommodate the plurality of cell members, the space-forming members including a substrate covering at least one of the positive electrode or the negative electrode of the cell member and a frame surrounding the side surfaces of the cell members, the cell members being stacked alternately via the substrates of the space-forming members, and the bonding surfaces of adjacent frames being bonded together, and a first distance from a first surface of the substrate on the side where the positive electrode current collector is provided to the first bonding surface of the frame and a second distance from a second surface of the substrate on the side where the negative electrode current collector is provided to the second bonding surface of the frame are different. [Effects of the Invention]

[0011] According to the present invention, a battery includes a plurality of cell members each including 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, and a plurality of space-forming members that form spaces to individually accommodate the plurality of cell members, wherein the space-forming member has a substrate that covers at least one of the positive electrode or the negative electrode of the cell member, and a frame that surrounds the side surfaces of the cell member, and the cell members are stacked alternately with the substrates of the space-forming members interposed between them, and the bonding surfaces of adjacent frames are bonded together, and a first distance from a first surface of the substrate on the side where the positive electrode current collector is provided to the first bonding surface of the frame is different from a second distance from a second surface of the substrate on the side where the negative electrode current collector is provided to the second bonding surface of the frame. Therefore, even when components such as a current collector and an active material layer are placed on a substrate during manufacturing, by adopting a space-forming member that can reduce the amount by which each component protrudes in the stacking direction from the frame body placed on the periphery of the substrate, manufacturing defects caused by each component protruding from the space-forming member can be prevented. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing the structure of a bipolar lead-acid battery according to a first embodiment of the present invention. [Figure 2]1 is an enlarged cross-sectional view showing a portion of the structure of a bipolar lead-acid battery according to a first embodiment of the present invention. [Figure 3] 1 is an enlarged cross-sectional view of a portion of the structure of a bipolar lead-acid battery according to a first embodiment of the present invention, showing a state in which a plurality of separators are arranged. [Figure 4] 1 is a cross-sectional view showing a bipolar lead-acid battery according to a first embodiment of the present invention in which a part of the structure is different. [Figure 5] FIG. 4 is a cross-sectional view showing the structure of a bipolar lead-acid battery according to a second embodiment of the present invention. [Figure 6] FIG. 5 is an enlarged cross-sectional view showing a portion of the structure of a bipolar lead-acid battery according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each embodiment described below shows an example of the present invention. Furthermore, various modifications and improvements can be made to each of these embodiments, and such modifications and improvements can also be included in the present invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the inventions described in the claims and their equivalents. Note that the following description will use a lead-acid battery as an example from among various storage batteries.

[0014] (First embodiment) [Overall structure] First, the overall configuration of a bipolar lead-acid battery according to a first embodiment of the present invention will be described. Fig. 1 is a cross-sectional view showing the structure of a bipolar lead-acid battery 100 according to an embodiment of the present invention.

[0015] As shown in FIG. 1, a bipolar lead-acid battery 100 according to the first embodiment of the present invention includes a plurality of cell members 110, a plurality of bipolar plates (space forming members) 120, a first end plate (space forming member) 130, and a second end plate (space forming member) 140.

[0016] 1 shows a bipolar lead-acid battery 100 in which three cell components 110 are stacked, but the number of cell components 110 is determined by the battery design. The number of bipolar plates 120 is also determined by the number of cell components 110.

[0017] 1 and 2, the stacking direction of the cell members 110 is defined as the Z direction (the vertical direction in FIG. 1 or FIG. 2), and directions perpendicular to the Z direction and perpendicular to each other are defined as the X direction and the Y direction. The Z direction, which is the stacking direction of the cell members 110, is parallel to the vertical direction.

[0018] The cell member 110 includes a positive electrode 111, a negative electrode 112, and an electrolyte layer (separator) 113. The positive electrode 111 includes a positive electrode lead foil 111a, which is a positive electrode current collector made of lead or a lead alloy, and a positive electrode active material layer 111b. The negative electrode 112 includes a negative electrode lead foil 112a, which is a negative electrode current collector made of lead or a lead alloy, and a negative electrode active material layer 112b.

[0019] This positive electrode lead foil 111a is provided on one surface of the bipolar plate 120 by an adhesive 150 (described later) provided between one surface of the bipolar plate 120 (the surface facing upward in the drawing of FIG. 1) and the positive electrode lead foil 111a. Therefore, on one surface of the bipolar plate 120, an adhesive layer (adhesive 150), the positive electrode lead foil 111a, and the positive electrode active material layer 111b are laminated in this order.

[0020] On the other hand, the negative electrode lead foil 112a is attached to the other surface of the bipolar plate 120 by an adhesive 150 (described later) provided between the other surface of the bipolar plate 120 (the surface facing downward in the drawing of FIG. 1) and the negative electrode lead foil 112a. Therefore, on the other surface of the bipolar plate 120, an adhesive layer (adhesive 150), the negative electrode lead foil 112a, and the negative electrode active material layer 112b are laminated in this order. The positive electrode 111 and the negative electrode 112 are electrically connected via a conductor 160 (described later).

[0021] The separator 113 is made of, for example, a glass fiber mat impregnated with an electrolyte solution containing sulfuric acid. The separator 113 is sandwiched between a positive electrode active material layer 111b provided on one of the opposing bipolar plates 120 and a negative electrode active material layer 112b provided on the other bipolar plate 120. 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 layered in this order.

[0022] In the bipolar lead-acid battery 100 according to the first embodiment of the present invention having such a configuration, as described above, the bipolar plate 120, the positive electrode lead foil 111a, the positive electrode active material layer 111b, the negative electrode lead foil 112a, and the negative electrode active material layer 112b constitute a bipolar electrode. A bipolar electrode is an electrode that functions as both a positive electrode and a negative electrode in one sheet.

[0023] Of course, a bipolar storage battery includes a configuration in which one surface of a single current collector functions as a positive current collector and the other surface functions as a negative current collector. Furthermore, a configuration in which a positive electrode lead foil 111a is provided on one surface of a substrate 121, and a negative electrode lead foil 112a is provided on the other surface, as in the bipolar lead-acid battery 100 according to the embodiment of the present invention, and the positive electrode lead foil 111a and the negative electrode lead foil 112a are electrically connected via a conductor 160 inserted into a through-hole 121a in the substrate 121, as will be described later, can also be considered a single current collector (positive electrode lead foil 111a, substrate 121, and negative electrode lead foil 112a). Therefore, the bipolar lead-acid battery 100 according to the embodiment of the present invention is also a type of bipolar storage battery.

[0024] The bipolar lead-acid battery 100 according to the first embodiment of the present invention is formed by stacking a plurality of cell members 110, each of which has a separator 113 interposed between a positive electrode 111 and a negative electrode 112, and bipolar plates 120 arranged in pairs to sandwich the cell member 110. The outermost layer is assembled with a first end plate 130 and a second end plate 140, thereby forming a battery configuration in which the cell members 110 are connected in series.

[0025] The dimensions in the X and Y directions of the positive electrode lead foil 111a are larger than those of the positive electrode active material layer 111b. Similarly, the dimensions in the X and Y directions of the negative electrode lead foil 112a are larger than those of the negative electrode active material layer 112b. Furthermore, 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 dimension (thicker) of the positive electrode active material layer 111b is larger (thicker) than that of the negative electrode active material layer 112b.

[0026] The multiple cell members 110 are stacked and arranged at intervals in the Z direction, and the substrates 121 of the bipolar plates 120 are arranged in these intervals. In other words, the multiple cell members 110 are stacked alternately with the substrates 121 of the bipolar plates 120 sandwiched between them.

[0027] In this way, the plurality of bipolar plates 120, the first end plate 130, and the second end plate 140 are space forming members for forming a plurality of spaces (cells) C that individually accommodate a plurality of cell members 110.

[0028] That is, the bipolar plate 120 is a space-forming member that covers both the positive electrode 111 side and the negative electrode 112 side of the cell member 110 and includes a substrate 121 having a rectangular planar shape, and a frame body 122 that surrounds the side surface of the cell member 110 and covers the four end faces of the substrate 121.

[0029] 1, the bipolar plate 120 further includes pillars 123 that protrude perpendicularly from both sides of the substrate 121. The number of pillars 123 protruding from each side of the substrate 121 may be one or more.

[0030] The substrate 121, frame 122, and column 123 that make up the bipolar plate 120 are integrally formed from, for example, a thermoplastic resin. Examples of the thermoplastic resin that forms the bipolar plate 120 include acrylonitrile-butadiene-styrene copolymer (ABS resin) and polypropylene. These thermoplastic resins have excellent moldability and sulfuric acid resistance. Therefore, even if the bipolar plate 120 comes into contact with an electrolyte, the bipolar plate 120 is unlikely to decompose, deteriorate, or corrode.

[0031] In the Z direction, the dimension of the frame body 122 is larger than the dimension (thickness) of the substrate 121, and the dimension between the protruding end faces of the pillar portions 123 is the same as the dimension of the frame body 122. Then, by stacking multiple bipolar plates 120 with the frame bodies 122 and the pillar portions 123 in contact with each other, a space C is formed between the substrates 121. The dimension of the space C in the Z direction is maintained by the pillar portions 123 in contact with each other.

[0032] 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 are respectively formed with through holes 111c, 111d, 112c, 112d, and 113a through which the columnar portion 123 passes.

[0033] The substrate 121 of the bipolar plate 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 greater than the depth 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 positive electrode lead foil 111a and the negative electrode lead foil 112a in the X and Y directions.

[0034] The substrate 121 of the bipolar plate 120 is disposed between adjacent cell members 110 in the Z direction. The positive electrode lead foil 111a of the cell member 110 is disposed in the first recess 121b of the substrate 121 of the bipolar plate 120 via an adhesive 150. The negative electrode lead foil 112a of the cell member 110 is disposed in the second recess 121c of the substrate 121 of the bipolar plate 120 via an adhesive 150.

[0035] Here, a further description will be given of the bipolar plate 120. Fig. 2 is an enlarged cross-sectional view showing a part (bipolar plate 120) of the structure of the bipolar lead-acid battery 100 according to the first embodiment of the present invention.

[0036] In the bipolar plate 120 according to the first embodiment of the present invention shown in FIG. 2, a first distance PL1 from a first joining surface 122a of the frame 122 to a first recess 121b (the surface that becomes the first recess 121b will be referred to as the "first surface") where a positive electrode current collector (positive electrode lead foil) 111a is provided on the substrate 121 when adjacent space forming members (bipolar plates 120) are joined, and a second distance NL1 from a second joining surface 122b of the frame 122 to a second recess 121c (the surface that becomes the second recess 121c will be referred to as the "second surface") where a negative electrode current collector (negative electrode lead foil) 112a is provided on the substrate 121 when adjacent space forming members (bipolar plates 120) are joined, are different.

[0037] That is, in the bipolar plate 120, the Z-direction distance (first distance PL1) in the space accommodating the positive electrode lead foil 111a, the positive electrode active material layer 111b, and the separator 113 arranged in contact with the positive electrode active material layer 111b is longer than the Z-direction distance (second distance NL1) in the space accommodating the negative electrode lead foil 112a, the negative electrode active material layer 112b, and the separator 113 arranged in contact with the negative electrode active material layer 112b.

[0038] The bipolar plate 120 according to the first embodiment of the present invention is formed so that the first distance PL1 is greater than the second distance NL1. Therefore, in the bipolar plate 120A, the substrate 121A is positioned not at the approximate center of the Z-direction height of the frame 122A but at a position shifted downward in the Z-direction.

[0039] Therefore, even if the positive electrode lead foil 111a, the positive electrode active material layer 111b, and the separator 113 are laminated in this order via the adhesive 150 in the first recess 121b on the positive electrode 111 side, it is possible to reduce the possibility that the separator 113 will protrude from the first bonding surface 122a of the frame body 122. Even if the separator 113 protrudes, the amount of protrusion can be reduced.

[0040] Therefore, even when each component such as the positive electrode lead foil 111a is stacked, it is possible to prevent each component from protruding from the first joint surface 122a of the frame body 122 and becoming misaligned, thereby avoiding defects during manufacturing.

[0041] Furthermore, if the bipolar plate 120 is formed so that the relationship of first distance PL1 > second distance NL1 holds, stress will be applied to the frame body on the positive electrode side, which has the longer distance, so that it closes inward, and it is possible that the substrate 121 will bend in a convex shape toward the negative electrode 112 side, which has the shorter distance.

[0042] Therefore, in the first embodiment of the present invention, the thickness in the Z direction of the positive electrode lead foil 111a when stacked and the thickness in the Z direction of the negative electrode lead foil 112a when stacked may be the same, but it is preferable that the thickness of the positive electrode lead foil 111a is formed to be thicker than the thickness of the negative electrode lead foil 112a.

[0043] By setting the thickness of the positive electrode lead foil 111a and the negative electrode lead foil 112a in this manner, for example, after the positive electrode lead foil 111a is placed in the first recess 121b of the substrate 121 via the adhesive 150, bending of the substrate due to the influence of heat generated by thermal curing or chemical conversion of the adhesive can be suppressed by the difference in linear expansion coefficient between the substrate and the lead foil.

[0044] Furthermore, even if the bipolar plate 120 is formed so that the relationship of first distance PL1 > second distance NL1 holds, the adjacent joined bipolar plates 120 are also formed to have a similar shape, so the Z-direction distance in the space C that accommodates the cell member 110 can be secured to be the same as when the substrate 121 is provided at approximately the center of the frame body 122 in the Z direction.

[0045] A conductor 160 is disposed in the through-hole 121a of the substrate 121 of the bipolar plate 120. Both end faces of the conductor 160 are in contact with and joined to the positive electrode lead foil 111a and the negative electrode lead foil 112a. That is, the positive electrode lead foil 111a and the negative electrode lead foil 112a are electrically connected by the conductor 160. As a result, all of the multiple cell members 110 are electrically connected in series.

[0046] A cover plate 170 is provided on the outer edge of the positive electrode lead foil 111a to cover the outer edge. This cover plate 170 is, for example, a thin frame body having rectangular inner and outer outlines. The inner edge of the cover plate 170 overlaps the outer edge of the positive electrode lead foil 111a, and the outer edge of the cover plate 170 overlaps the periphery of the first recess 121b on one surface of the substrate 121.

[0047] That is, the rectangle forming the inner outline of the cover plate 170 is smaller than the rectangle forming the outer outline of the positive electrode lead foil 111a, and the rectangle forming the outer outline of the cover plate 170 is larger than the rectangle forming the opening surface of the first recess 121b.

[0048] The adhesive 150 wraps around from the end face of the positive electrode lead foil 111a to the outer edge of the opening side of the first recess 121b and is disposed between the inner edge of the cover plate 170 and the outer edge of the positive electrode lead foil 111a. The adhesive 150 is also disposed between the outer edge of the cover plate 170 and one surface of the substrate 121.

[0049] That is, the cover plate 170 is fixed by the adhesive 150 over the periphery of the first recess 121b on one surface of the substrate 121 and the outer periphery of the positive electrode lead foil 111a. As a result, the outer periphery of the positive electrode lead foil 111a is covered with the cover plate 170 even at the boundary with the periphery of the first recess 121b.

[0050] 1, the outer edge of the negative electrode lead foil 112a may also be covered with a cover plate similar to the cover plate 170 that covers the outer edge of the positive electrode lead foil 111a. Although the cover plate has been described as a thin plate-like frame, it may be a tape-like object or the like as long as it is resistant to the electrolyte (sulfuric acid).

[0051] 1, the first end plate 130 is a space-forming member that includes a substrate 131 that covers the positive electrode side of the cell member 110, and a frame 132 that surrounds the side surface of the cell member 110. The first end plate 130 also includes a pillar portion 133 that protrudes vertically from one surface of the substrate 131 (the surface facing the substrate 121 of the bipolar plate 120 that is arranged closest to the positive electrode side).

[0052] The planar shape of the substrate 131 is rectangular, and the four end faces of the substrate 131 are covered with a frame 132. The substrate 131, frame 132, and pillars 133 are integrally formed from, for example, the above-mentioned thermoplastic resin. The number of pillars 133 protruding from one surface of the substrate 131 may be one or more. However, the number corresponds to the number of pillars 123 of the bipolar plate 120 that are to come into contact with the pillars 133.

[0053] In the Z direction, the dimension of the frame body 132 is larger than the dimension (thickness) of the substrate 131, and the dimension between the protruding end faces of the column portions 133 is the same as the dimension of the frame body 132. The first end plate 130 is stacked with the frame body 132 and the column portions 133 in contact with the frame body 122 and the column portions 123 of the bipolar plate 120 arranged on the outermost side (positive electrode side).

[0054] This forms a space C between the substrate 121 of the bipolar plate 120 and the substrate 131 of the first end plate 130. The Z-direction dimension of the space C is maintained by the pillar portions 123 of the bipolar plate 120 and the pillar portions 133 of the first end plate 130, which are in contact with each other.

[0055] The positive electrode lead foil 111a, positive electrode active material layer 111b, and separator 113 of the cell member 110 arranged on the outermost side (positive electrode side) have through holes 111c, 111d, and 113a formed therein, respectively, for allowing the columnar portion 133 to pass therethrough.

[0056] A recess 131b is formed on one surface of the substrate 131 of the first end plate 130. The dimensions of the recess 131b in the X and Y directions correspond to the dimensions of the positive electrode lead foil 111a in the X and Y directions.

[0057] The positive electrode lead foil 111a of the cell member 110 is placed in the recess 131b of the substrate 131 of the first end plate 130 via an adhesive 150. Similarly to the substrate 121 of the bipolar plate 120, a cover plate 170 is fixed to one surface of the substrate 131 with the adhesive 150. As a result, the outer edge of the positive electrode lead foil 111a is covered with the cover plate 170, even at the boundary with the periphery of the recess 131b.

[0058] The first end plate 130 also includes a positive electrode terminal (not shown in FIG. 1) electrically connected to the positive electrode lead foil 111a in the recess 131b.

[0059] The shape of the first end plate 130 is formed so that the volume of the space C between the first end plate 130 and the bipolar plate 120 adjacent to the first end plate 130 can be made the same as the volume of the space C formed between two adjacent bipolar plates 120.

[0060] That is, the distance between the recess 131b in the first end plate 130 and the second recess 121c of the bipolar plate 120 joined to the first end plate 130 is set to be the same distance in the Z direction in the space C formed by two adjacent bipolar plates 120 (the distance between the first recess 121b and the second recess 121c arranged in opposing positions).

[0061] By forming the first end plate 130 in this shape, the cell member 110 can be accommodated in the space C formed by the first end plate 130 and the bipolar plate 120 without protruding.

[0062] The second end plate 140 is a space-forming member that includes a substrate 141 that covers the negative electrode side of the cell member 110, and a frame 142 that surrounds the side surface of the cell member 110. The second end plate 140 also includes a column portion 143 that protrudes vertically from one surface of the substrate 141 (the surface facing the substrate 121 of the bipolar plate 120 that is arranged on the most negative electrode side).

[0063] The planar shape of the substrate 141 is rectangular, and the four end faces of the substrate 141 are covered with a frame 142. The substrate 141, frame 142, and pillars 143 are integrally formed from, for example, the above-mentioned thermoplastic resin. The number of pillars 143 protruding from one surface of the substrate 141 may be one or more. However, the number corresponds to the number of pillars 123 of the bipolar plate 120 that are to come into contact with the pillars 143.

[0064] In the Z direction, the dimension of the frame body 142 is larger than the dimension (thickness) of the substrate 141, and the dimension between the protruding end faces of the two pillar portions 143 is the same as the dimension of the frame body 142. The second end plate 140 is stacked with the frame body 142 and the pillar portions 143 in contact with the frame body 122 and the pillar portions 123 of the bipolar plate 120 arranged on the outermost side (negative electrode side).

[0065] This forms a space C between the substrate 121 of the bipolar plate 120 and the substrate 141 of the second end plate 140. The Z-direction dimension of the space C is maintained by the pillar portions 123 of the bipolar plate 120 and the pillar portions 143 of the second end plate 140, which are in contact with each other.

[0066] 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 (negative electrode side) have through holes 112c, 112d, and 113a formed therein, respectively, for allowing the column portion 143 to pass therethrough.

[0067] 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 negative electrode lead foil 112a in the X and Y directions.

[0068] The negative electrode lead foil 112a of the cell member 110 is placed in the recess 141b of the substrate 141 of the second end plate 140 via adhesive 150. The second end plate 140 also includes a negative electrode terminal (not shown in FIG. 1) that is electrically connected to the negative electrode lead foil 112a in the recess 141b.

[0069] The shape of the second end plate 140 is formed so that the volume of the space C between the second end plate 140 and the bipolar plate 120 adjacent to the second end plate 140 can be made the same as the volume of the space C formed between two adjacent bipolar plates 120.

[0070] That is, the distance between the recess 141b in the second end plate 140 and the second recess 121c of the bipolar plate 120 joined to the second end plate 140 is set to be the same distance in the Z direction in the space C formed by two adjacent bipolar plates 120 (the distance between the first recess 121b and the second recess 121c arranged in opposing positions).

[0071] By forming the second end plate 140 in this shape, the cell member 110 can be accommodated in the space C formed by the second end plate 140 and the bipolar plate 120 without protruding.

[0072] Comparing the first end plate 130 and the second end plate in the first embodiment, there is the following difference: The distance between the recess 131b in the first end plate 130 and the second recess 121c in the bipolar plate 120 joined to the first end plate 130 is longer than the distance between the recess 141b in the second end plate 140 and the first recess 121b in the bipolar plate 120 joined to the second end plate 140.

[0073] Here, when joining opposing bipolar plates 120 together, the first end plate 130 and the opposing bipolar plate 120, or the second end plate 140 and the opposing bipolar plate 120, various welding methods can be used, such as vibration welding (vibration welding), ultrasonic welding, and hot plate welding. Of these, vibration welding involves welding by vibrating the surfaces to be joined while applying pressure, and has a fast welding cycle and good reproducibility. Therefore, vibration welding is more preferably used.

[0074] The objects to be welded include not only the frames arranged at opposing positions on the opposing bipolar plate 120, first end plate 130, and second end plate 140, but also the respective pillars.

[0075] [Manufacturing method] The bipolar lead-acid battery 100 of this embodiment can be manufactured, for example, by a method including the steps described below.

[0076] <Manufacturing process of bipolar plates with lead foil for positive and negative electrodes> First, prepare a bipolar plate 120 having a shape satisfying the relationship of first distance PL1 > second distance NL1 as described above. Then, place the substrate 121 of the bipolar plate 120 on a workbench with the first recess 121b facing upward. Then, apply adhesive 150 to the first recess 121b, and insert the positive electrode lead foil 111a into the first recess 121b. At this time, pass the column portion 123 of the bipolar plate 120 through the through hole 111c of the positive electrode lead foil 111a. Then, cure the adhesive 150, and attach the positive electrode lead foil 111a to one surface of the substrate 121.

[0077] Next, the substrate 121 is placed on a workbench with the second recess 121c facing upward, and the conductor 160 is inserted into the through-hole 121a. Then, adhesive 150 is applied to the second recess 121c, and the negative electrode lead foil 112a is placed in the second recess 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. The adhesive 150 is cured, and the negative electrode lead foil 112a is attached to the other surface of the substrate 121.

[0078] Next, the substrate 121 is placed on a workbench with the first recess 121b side facing up. Then, adhesive 150 is applied to the outer edge of the positive electrode lead foil 111a and to the upper surface of the substrate 121 that will become the edge of the first recess 121b, and a cover plate 170 is placed on top of that and the adhesive 150 is cured. In this way, the cover plate 170 is fixed over the outer edge of the positive electrode lead foil 111a and over the portion of the substrate 121 that is continuous with that outer edge (the peripheral edge of the first recess 121b).

[0079] Next, resistance welding is performed to connect the conductor 160 to the positive electrode lead foil 111a and the negative electrode lead foil 112a, thereby obtaining the bipolar plate 120 with positive and negative electrode lead foils. The required number of bipolar plates 120 with positive and negative electrode lead foils are prepared.

[0080] <Production process of end plates with lead foil for positive electrodes> The first end plate 130 described above is prepared. The substrate 131 of the first end plate 130 is placed on a workbench with the recessed portion 131b facing upward. Adhesive 150 is then applied to the recessed portion 131b, and the positive electrode lead foil 111a is placed in the recessed portion 131b and the adhesive 150 is allowed to harden. At this time, the column portion 133 of the end plate 130 is passed through the through hole 111c of the positive electrode lead foil 111a. The adhesive 150 is allowed to harden, and the positive electrode lead foil 111a is attached to one surface of the substrate 131.

[0081] Next, adhesive 150 is applied to the outer edge of the positive electrode lead foil 111a and to the upper surface of the substrate 131, which will be the edge of the recess 131b. A cover plate 170 is placed on this adhesive 150 and the adhesive 150 is cured. This fixes the cover plate 170 over the outer edge of the positive electrode lead foil 111a and the portion of the substrate 131 that is continuous with the outer edge. This results in an end plate with positive electrode lead foil.

[0082] <Manufacturing process of end plates with lead foil for negative electrodes> The second end plate 140 described above is prepared. The substrate 141 of the second end plate 140 is placed on a workbench with the recessed portion 141b facing upward. Adhesive 150 is then applied to the recessed portion 141b, and the negative electrode lead foil 112a is placed in the recessed portion 141b and the adhesive 150 is cured. At this time, the column portion 143 of the second end plate 140 is passed through the through hole 112c in the negative electrode lead foil 112a. The adhesive 150 is cured to obtain the second end plate 140 in which the negative electrode lead foil 112a is attached to one surface of the substrate 141.

[0083] <The process of stacking and joining plates> First, the first end plate 130, to which the positive electrode lead foil 111a and cover plate 170 are fixed, is placed on a workbench with the positive electrode lead foil 111a facing up. The positive electrode active material layer 111b is then placed inside the cover plate 170 and placed on top of the positive electrode lead foil 111a. At this time, the column portions 133 of the first end plate 130 are passed through the through holes 111d in the positive electrode active material layer 111b. Next, the separator 113 and the negative electrode active material layer 112b are placed on top of the positive electrode active material layer 111b.

[0084] Next, the bipolar plate 120 with the positive and negative lead foils is placed with the negative electrode lead foil 112a side facing downwards on the first end plate 130 in this state. At this time, the column parts 123 of the bipolar plate 120 are passed through the through holes 113a of the separator 113 and the through holes 112d of the negative electrode active material layer 112b, and placed on the column parts 133 of the first end plate 130. Then, the frame 122 of the bipolar plate 120 is placed on the frame 132 of the first end plate 130.

[0085] In this state, the first end plate 130 is fixed, and vibration welding is performed while the bipolar plate 120 is vibrated in the diagonal direction of the substrate 121 to bond the bonding surfaces together. As a result, the frame 122 of the bipolar plate 120 is bonded onto the frame 132 of the first end plate 130. In addition, the pillar portions 123 of the bipolar plate 120 are bonded onto the pillar portions 133 of the first end plate 130.

[0086] As a result, the bipolar plate 120 is joined onto the first end plate 130. The cell member 110 is placed in the space C formed by the first end plate 130 and the bipolar plate 120, with the positive electrode lead foil 111a exposed on the upper surface of the bipolar plate 120.

[0087] Next, the positive electrode active material layer 111b, separator 113, and negative electrode active material layer 112b are placed in this order on the assembly thus obtained, in which the bipolar plate 120 is joined to the first end plate 130. Thereafter, another bipolar plate 120 with positive and negative electrode lead foils is placed with the negative electrode lead foil 112a side facing downward.

[0088] In this state, the combined body is fixed, and another bipolar plate 120 with lead foil for positive and negative electrodes is vibration-welded while being vibrated in the diagonal direction of the substrate 121. This vibration welding process is continued until the required number of bipolar plates 120 are joined onto the first end plate 130.

[0089] Finally, the positive electrode active material layer 111b, separator 113, and negative electrode active material layer 112b are placed in this order on the uppermost bipolar plate 120 of the combined assembly in which all the bipolar plates 120 are joined together. Then, a second end plate 140 is placed with the negative electrode lead foil 112a side facing downward.

[0090] In this state, the combined assembly 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 onto the uppermost bipolar plate 120 of the combined assembly to which all the bipolar plates 120 have been joined.

[0091] In the above description, the layers are stacked in order from the first end plate 130 to the second end plate 140. However, the stacking order may be reversed, from the second end plate 140 to the first end plate 130.

[0092] <Injection and chemical conversion process> In the stacking and joining process of the plates described above, a joining structure is formed by vibration welding of the opposing surfaces of the frame bodies. Then, a predetermined amount of electrolyte is injected into each space C through a through-hole (not shown), and the separator 113 is impregnated with the electrolyte. Then, by performing chemical formation under predetermined conditions, the bipolar lead-acid battery 100 can be manufactured.

[0093] As described above, in the first embodiment of the present invention, even when components such as current collectors and active material layers are arranged on a substrate during manufacturing, by employing a space-forming member that can reduce the amount by which each component protrudes in the stacking direction from a frame that is arranged on the periphery of the substrate, it is possible to provide a bipolar storage battery that can prevent manufacturing defects caused by each component protruding from the space-forming member.

[0094] As described above, by using the bipolar plate 120 and the first end plate 130 according to the first embodiment of the present invention, even when components such as the positive electrode lead foil 111a, the positive electrode active material layer 111b, and the separator 113 are laminated on the first end plate 130 or the bipolar plate 120 during the manufacturing process, the amount of protrusion of each component from the frame 132 or the frame 122 in the Z direction can be reduced.

[0095] If the amount by which each component protrudes in the Z direction from the frame 132 or the frame 122 can be reduced, the occurrence of components being pinched during joining will be reduced, and manufacturing defects can be prevented.

[0096] In the bipolar lead-acid battery 100 according to the first embodiment described above, an example has been given in which there is one separator 113, as shown in Fig. 1. However, the separator 113 may be made up of one sheet, or multiple separated separators 113 may be stacked to form a single separator 113 as a whole.

[0097] Fig. 3 is an enlarged cross-sectional view of a portion of the structure of the bipolar lead-acid battery 100 according to the first embodiment of the present invention, showing the arrangement of a plurality of separators 113. A plurality of separators 113A to 113c are arranged in the bipolar plate 120 shown in Fig. 3. That is, the second separator 113B and the third separator 113C are stacked in this order from the first separator 113A in contact with the positive electrode active material layer 111b upward in the Z direction in the drawing.

[0098] 3 shows three separators, namely, first separator 113A to third separator 113C. Therefore, when these are collectively referred to hereinafter, they will be referred to as "separators 113" as before. In this case, the number of separators 113 is not limited as long as there are multiple separators.

[0099] 2 shows a state in which the separator 113 does not protrude upward in the Z direction beyond the first bonding surface 122a of the frame body 122. On the other hand, in FIG. 3, a plurality of separators 113 are arranged so as to be in contact with the positive electrode active material layer 111b, and are further shown to protrude upward in the Z direction beyond the first bonding surface 122a of the frame body 122.

[0100] On the other hand, among the multiple separators 113 stacked in order from the first surface on the side of the substrate 121 where the positive electrode current collector 111a is provided, the distance between the first surface and the surface facing the first surface of the separator 113 located at the position farthest from the first surface is shorter than the first distance PL1.

[0101] 3, the separator disposed farthest from the first surface is third separator 113C. The distance between the first surface and the surface of third separator 113C facing the first surface, i.e., the lower surface of third separator 113C at the boundary between second separator 113B and third separator 113C, which are in contact with each other, is shorter than first distance PL1.

[0102] 3, the position of the lower surface of third separator 113C in the Z direction is lower than the position of first bonding surface 122a in the Z direction. Even when separator 113 is made up of multiple separators in this way, the lower surface of the separator located farthest from the first surface is located lower in the Z direction than first bonding surface 122a.

[0103] Therefore, even if the separator located farthest from the first surface is displaced in the X direction, its lower surface does not protrude in the Z direction beyond the first bonding surface 122a. This reduces the possibility of components being pinched during bonding, thereby preventing manufacturing defects.

[0104] Regarding the presence of a plurality of separators 113, there may be a plurality of separators 113 arranged on the negative electrode side in Fig. 3. In other words, in this case, among the plurality of separators 113 stacked in order from the second surface, the distance between the second surface and the surface facing the second surface of the separator 113 arranged at the position farthest from the second surface is shorter than the second distance NL1.

[0105] Next, in the bipolar lead-acid battery 100 in the first embodiment described above, for example, as shown in Fig. 1, the column portion 123 is provided. However, the bipolar lead-acid battery 100 does not necessarily need to be provided with the column portion 123. This point will be described with reference to Fig. 4.

[0106] 4 is a cross-sectional view showing a partially different structure of the bipolar lead-acid battery 100 according to the first embodiment of the present invention. The bipolar plate 120 shown in FIG. 4 does not have a pillar portion.

[0107] 4, there is no problem in employing the structure described above even when the bipolar plate 120 does not have pillars. Therefore, by employing a space-forming member that can reduce the amount by which each component, such as a current collector or an active material layer, protrudes in the stacking direction from a frame that is disposed on the periphery of the substrate when the components are arranged on the substrate during manufacturing, it is possible to provide a bipolar storage battery that can prevent manufacturing defects caused by each component protruding from the space-forming member.

[0108] (Second embodiment) Next, a second embodiment of the present invention will be described. In the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and redundant descriptions of the same components will be omitted.

[0109] The bipolar plate 120 described in the first embodiment of the present invention has a shape satisfying the relationship of first distance PL1 > second distance NL1. However, similar effects can be obtained with bipolar plates having shapes other than this. Therefore, a bipolar plate 120A according to the second embodiment will be described below with reference to FIGS. 5 and 6.

[0110] Fig. 5 is a cross-sectional view showing the structure of a bipolar lead-acid battery 100A according to a second embodiment of the present invention. Fig. 6 is an enlarged cross-sectional view showing a portion (bipolar plate 120A) of the structure of the bipolar lead-acid battery 100A according to the second embodiment of the present invention. Fig. 6 shows one bipolar plate 120A.

[0111] As shown in FIG. 6, in the space forming member (bipolar plate 120A) in the second embodiment, a first distance PL2 from a first bonding surface 122Aa of the frame body 122A to a first recess 120Ab (first surface) on the substrate 121A where the positive electrode current collector 111a is provided when adjacent space forming members are joined, and a second distance NL2 from a second bonding surface 122Ab of the frame body 122A to a second recess 121Ac (second surface) on the substrate 121Aa where the negative electrode current collector 112a is provided when adjacent space forming members are joined, are different.

[0112] That is, in the bipolar plate 120A, the Z-direction distance (first distance PL2) in the space accommodating the positive electrode lead foil 111a, the positive electrode active material layer 111b, and the separator 113 arranged in contact with the positive electrode active material layer 111b is shorter than the Z-direction distance (second distance NL2) in the space accommodating the negative electrode lead foil 112a, the negative electrode active material layer 112b, and the separator 113 arranged in contact with the negative electrode active material layer 112b.

[0113] The bipolar plate 120A according to the second embodiment of the present invention is formed so that the first distance PL2 is smaller than the second distance NL2. Therefore, in the bipolar plate 120A, the substrate 121A is positioned not at the approximate center of the Z-direction height of the frame 122A, but at a position shifted upward in the Z-direction. When the positive electrode lead foil 111a and the positive electrode active material layer 111b are placed in this order on the substrate 121A of the bipolar plate 120A, each of these components protrudes from the frame 122A.

[0114] Like the bipolar plate 120A in the second embodiment, by forming the bipolar plate 120A so that the first distance PL2 is smaller than the second distance NL2, the positive electrode active material layer 111b can be pressed with a roller and placed in closer contact with the positive electrode lead foil 111a.

[0115] As described above, the first end plate 130A and the second end plate 140A are formed to fit the shape of the bipolar plate 120A, as shown in Fig. 5. That is, when comparing the heights (distance in the Z direction) of the first end plate 130A and the second end plate 140A in the second embodiment, the height of the first end plate 130A is shorter (less than) the height of the second end plate 140A.

[0116] [Manufacturing method] The bipolar lead-acid battery 100A of this embodiment can be manufactured, for example, by a method including the steps described below.

[0117] <Manufacturing process of bipolar plates with lead foil for positive and negative electrodes> First, a bipolar plate 120A having a shape satisfying the relationship of first distance PL2<second distance NL2 as described above is prepared. Then, as described in the first embodiment, adhesive 150 is applied to the first recess 121b, and the positive electrode lead foil 111a is placed and attached in the first recess 121b.

[0118] Next, the substrate 121 is placed on a workbench with the second recess 121c side facing up, and the conductor 160 is inserted into the through-hole 121a. Then, adhesive 150 is applied to the second recess 121c, and the negative electrode lead foil 112a is placed and attached in the second recess 121c.

[0119] Furthermore, a cover plate 170 is fixed with adhesive 150 over the outer edge of the positive lead foil 111a and over the portion of the substrate 121 that is continuous with the outer edge (the peripheral edge of the first recess 121b). Then, resistance welding is performed to connect the conductor 160, the positive lead foil 111a, and the negative lead foil 112a. This results in a bipolar plate 120A with positive and negative lead foils. The required number of bipolar plates 120A with positive and negative lead foils are prepared.

[0120] <Production process of end plates with lead foil for positive electrodes> First, prepare the first end plate 130A as described above. Place the substrate 131A of the first end plate 130A on a workbench with the recess 131Ab facing upward. Then, apply adhesive 150 to the recess 131Ab, place the positive electrode lead foil 111a in the recess 131Ab, and attach the positive electrode lead foil 111a to one surface of the substrate 131A.

[0121] Next, a cover plate 170 is fixed onto the outer edge of the positive electrode lead foil 111a and onto the portion of the substrate 131 that is continuous with the outer edge via an adhesive 150. In this way, an end plate with positive electrode lead foil is obtained.

[0122] <Manufacturing process of end plates with lead foil for negative electrodes> The second end plate 140A described above is prepared. The substrate 141A of the second end plate 140A is placed on a workbench with the recess 141Ab facing upward. Adhesive 150 is then applied to the recess 141Ab, and the negative electrode lead foil 112a is placed in the recess 141Ab, and the negative electrode lead foil 112a is attached to one surface of the substrate 141A.

[0123] <The process of stacking and joining plates> First, the first end plate 130A is placed on a workbench with the positive electrode lead foil 111a facing upward. Then, the positive electrode active material layer 111b is placed inside the cover plate 170, which is then placed on top of the positive electrode lead foil 111a. At this time, the column portions 133 of the first end plate 130 are inserted into the through holes 111d of the positive electrode active material layer 111b.

[0124] Then, the positive electrode active material layer 111b is pressed downward in the Z direction with a roller toward the positive electrode lead foil 111a. Next, the separator 113 and the negative electrode active material layer 112b are placed on the positive electrode active material layer 111b.

[0125] Next, the bipolar plate 120A with the positive and negative lead foils is placed on the first end plate 130A in this state, with the negative lead foil 112a side facing downward. As described above, the bipolar plate 120A in the second embodiment of the present invention is formed so that the first distance PL2 is smaller than the second distance NL2. Therefore, the bipolar plate 120A is arranged to cover each component layered in order on the positive lead foil 111a.

[0126] At this time, the column sections 123 of the bipolar plate 120A are passed through the through holes 113a of the separator 113 and the through holes 112d of the negative electrode active material layer 112b, and placed on the column sections 133A of the first end plate 130A. Then, the frame 122A of the bipolar plate 120A is placed on the frame 132A of the first end plate 130A.

[0127] In this state, the first end plate 130A is fixed and vibration welding is performed, thereby joining the frame body 122A of the bipolar plate 120A onto the frame body 132A of the first end plate 130A.

[0128] The cell member 110 is placed in a space C formed by the first end plate 130A and the bipolar plate 120A, with the positive electrode lead foil 111a exposed on the top surface of the bipolar plate 120A.

[0129] Next, the positive electrode active material layer 111b, separator 113, and negative electrode active material layer 112b are placed in this order on the combined assembly in which the bipolar plate 120A is joined to the first end plate 130A. After that, another bipolar plate 120A with positive and negative electrode lead foils is placed on top of it with the negative electrode lead foil 112a side facing downward.

[0130] Here, too, the bipolar plate 120A in the second embodiment of the present invention is formed so as to satisfy the relationship of first distance PL2<second distance NL2. Therefore, the bipolar plate 120A is arranged so as to cover each of the components stacked in order on the positive electrode lead foil 111a.

[0131] In this state, the assembly is fixed and vibration welding is performed. This vibration welding process is continued until the required number of bipolar plates 120A are joined onto the first end plate 130A.

[0132] Finally, the positive electrode active material layer 111b, separator 113, and negative electrode active material layer 112b are placed in this order on the uppermost bipolar plate 120A of the combined assembly in which all the bipolar plates 120A are joined together. Then, the second end plate 140A is placed with the negative electrode lead foil 112a side facing downward.

[0133] As described above, the second end plate 140A in the second embodiment of the present invention is formed so that its height is greater than that of the first end plate 130A. Therefore, the second end plate 140A is disposed so as to cover the components stacked in order on the positive electrode lead foil 111a.

[0134] In this state, the assembly is fixed, and the second end plate 140A is vibration-welded. As a result, the second end plate 140A is joined to the top of the bipolar plate 120A of the assembly to which all the bipolar plates 120A have been joined. As explained above, this step is followed by the liquid injection and chemical conversion steps.

[0135] As described above, in the second embodiment of the present invention, even when components such as current collectors and active material layers are arranged on a substrate during manufacturing, by employing a space-forming member that can reduce the amount by which each component protrudes in the stacking direction from a frame that is arranged on the periphery of the substrate, it is possible to provide a bipolar storage battery that can prevent manufacturing defects caused by each component protruding from the space-forming member.

[0136] Furthermore, when placing the positive electrode active material layer 111b on the bipolar plate 120A, it can be placed while pressing it against the positive electrode lead foil 111a using a roller, which reduces the possibility of the positive electrode active material layer 111b peeling off from the positive electrode lead foil 111a.

[0137] Up to this point, we have described the bipolar plate 120 of the first embodiment and the bipolar plate 120A of the second embodiment. As described above, the former bipolar plate 120 is formed so that the first distance PL1 is greater than the second distance NL1. On the other hand, the latter bipolar plate 120A is formed so that the first distance PL2 is less than the second distance NL2.

[0138] In this way, in the bipolar plates 120, 120A, the first distances PL1, PL2 from the first bonding surfaces 122a, 122Aa of the frame bodies 122, 122A to the first recesses 121b, 111Ab (first surfaces) on which the positive electrode current collector 111a is provided on the substrates 121, 121A when adjacent space forming members 120, 120A are joined, and the second distances NL1, NL2 from the second bonding surfaces 122a, 122Aa of the frame bodies 122, 122A to the second recesses 121c, 111Ac (second surfaces) on which the negative electrode current collector 112a is provided on the substrates 121, 121A when adjacent space forming members 120, 120A are joined, are different.

[0139] Here, the ratio of the second distances NL1, NL2 to the first distances PL1, PL2 is 0.2:1 to 5:1. As described above, the first distances PL1, PL2 and the second distances NL1, NL2 are different, and therefore, cases where the ratio is 1:1 are excluded.

[0140] If the ratio is smaller than 0.2 or larger than 5, the substrate will be too close to the positive or negative side of the frame, and will no longer function as a bipolar plate.

[0141] In this way, the bipolar plate 120 used in the bipolar lead-acid battery 100 or the bipolar plate 120A used in the bipolar lead-acid battery 100A is formed so that the ratio of the second distances NL1, NL2 to the first distances PL1, PL2 is 0.2:1 to 5:1, as described above.

[0142] On the other hand, as described above, when the bipolar plate, the first end plate, and the second end plate are joined together during the manufacturing process of both the bipolar lead-acid battery 100 and the bipolar lead-acid battery 100A, for example, by vibration welding, the joining surfaces are melted and joined together.

[0143] Because vibration welding melts the joining surfaces of the frame bodies, the actual distances of the first distances PL1, PL2 or the second distances NL1, NL2 differ from those before joining. That is, because there is a melting margin, the distances are shorter after joining than before joining. However, the ratio of the second distances NL1, NL2 to the first distances PL1, PL2 described above does not change before or after vibration welding.

[0144] Therefore, depending on the joining method used to join the bipolar plate, the first end plate, and the second end plate, it may be necessary to take into consideration the "melt allowance," but in any case, the above-mentioned ratios will not change.

[0145] In the first embodiment, the case where a plurality of separators 113 are provided has been described using Fig. 3, and the case where no pillars are provided on the bipolar plate 120 has been described using Fig. 4. These details also apply to the bipolar lead-acid battery 100A in the second embodiment.

[0146] As mentioned above, the embodiments of the present invention have been described using a bipolar lead-acid battery as an example, but the above description does not exclude the application of the present invention to other storage batteries that use metals other than lead for the current collector plates, if the above description is also applicable to such batteries. [Explanation of symbols]

[0147] 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...Active material layer for negative electrode 113 Separator 120···Bipolar Plate 121....Bipolar plate substrate 121a... Through hole in substrate 121aa... Inner wall surface 121ab...Opening 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... Second end plate frame 150···Adhesive 160 Conductor 160a...Outer wall 161 Conductor 161a... Peripheral wall 162 Conductor 162a···Convex part 170···Cover plate 180...Protrusion 180a...Protruding tip 181...Protrusion 181a...Support part 181b...Holding part C···Cell (space that houses the cell components) M...Gap

Claims

1. a plurality of cell members each including 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; a plurality of space forming members that form spaces for individually accommodating the plurality of cell members; the space-forming member has a substrate that covers at least one of the positive electrode and the negative electrode of the cell member, and a frame that surrounds a side surface of the cell member, The cell members are alternately stacked via the substrates of the space-forming members, The joining surfaces of the adjacent frame bodies are joined together, a first distance from a first surface of the substrate on which the positive electrode current collector is provided to a first joint surface of the frame, and a second distance from a second surface of the substrate on which the negative electrode current collector is provided to a second joint surface of the frame, the first distance being different from a first distance from a first surface of the substrate on which the negative electrode current collector is provided to a second joint surface of the frame.

2. 2. The bipolar battery according to claim 1, wherein the ratio of the second distance to the first distance is 0.2:1 to 5:

1.

3. 2. The bipolar storage battery according to claim 1, wherein when the first distance is longer than the second distance, the thickness of the positive electrode current collector is thicker than the thickness of the negative electrode current collector.

4. 3. The bipolar storage battery according to claim 2, wherein when the first distance is longer than the second distance, the thickness of the positive electrode current collector is thicker than the thickness of the negative electrode current collector.

5. 2. The bipolar storage battery according to claim 1, wherein, when the cell member includes a plurality of separators, among the plurality of separators stacked in order from the first surface, the distance between the first surface and a surface facing the first surface of the separator that is disposed farthest from the first surface is shorter than the first distance, and among the plurality of separators stacked in order from the second surface, the distance between the second surface and a surface facing the second surface of the separator that is disposed farthest from the second surface is shorter than the second distance.

6. 6. 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.

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