Biplate for bipolar storage battery and bipolar storage battery

Abstract

To prevent adhesive contamination at the center of an end face of a conductor in a biplate for a bipolar storage battery manufactured by a method including the step of inserting a conductor into a through hole from above with the other side of a substrate having a current collector fixed to one side facing upward, and then performing resistance welding in a state where a liquid adhesive layer is present in a portion other than the through hole on the other side of the substrate.SOLUTION: A substrate 121 includes a cylindrical through hole 121a extending in a thickness direction, and a conductor 160 disposed in the through hole includes a large diameter portion 161 with the diameter corresponding to the diameter of the through hole and small diameter portions 162a, 162b. The small diameter portions is formed in at least one of both ends of he conductor. Recesses 170a and 170b are formed by an outer circumferential surface 1621 of the small diameter portion, a step surface 1611 between the large diameter portion and the small diameter portion, and an inner wall surface 1211 of the through hole in at least one of both ends of the substrate in the thickness direction, and both end surfaces of the conductor are joined to a positive electrode current collector plate and a negative electrode current collector plate, respectively.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a biplate for a bipolar storage battery and a bipolar storage battery. [Background technology]

[0002] In recent years, the number of power generation facilities using natural energy 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, a storage battery is used to level the power load. That is, when the amount of power generated is greater than the amount of power consumed, the difference is charged to the storage battery, and when the amount of power generated is less than the amount of power 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, a bipolar lead-acid battery described in Patent Document 1 below is known as such a conventional lead-acid battery.

[0003] This bipolar lead-acid battery has a resin substrate attached to the inside of a picture-frame-shaped resin frame. Lead layers are arranged on both sides of the substrate. A positive electrode active material layer is adjacent to the lead layer on one side of the substrate, and a negative electrode active material layer is adjacent to the lead layer on the other side. The battery also has a frame-shaped resin spacer, inside which a glass mat impregnated with an electrolyte is arranged. Multiple frames and spacers are alternately stacked, and the frames and spacers are bonded together with an adhesive or the like. The lead layers on both sides of the substrate are connected via through holes in the thickness direction of the substrate.

[0004] That is, the bipolar lead-acid battery described in Patent Document 1 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 separator (glass mat) present between the positive electrode and the negative electrode, and has a plurality of cell members stacked and arranged with spaces between them, and a plurality of space-forming members that form a plurality of spaces to individually accommodate the plurality of cell members.

[0005] The space-forming member includes a plate covering at least one of the positive and negative sides of the cell member, and a frame (frames of the bipolar plate and end plates and spacers) surrounding the side surfaces of the cell member. Furthermore, the cell members and the plates of the space-forming member are alternately stacked, and the lead layers on both sides of the substrate, which is the covering plate arranged between adjacent cell members, are joined via through-holes in the substrate, thereby electrically connecting the cell members in series and joining the opposing surfaces of adjacent frames to form the main body of the bipolar lead-acid battery.

[0006] Patent Document 2 describes a biplate structure having a substrate disposed between adjacent cell members that constitute a bipolar storage battery, in which a positive electrode current collector that constitutes one of the cell members is bonded to one surface of the substrate, a negative electrode current collector that constitutes the other cell member is bonded to the other surface of the substrate, a columnar conductor is disposed in a through hole in the substrate, and both end surfaces of the conductor are joined to the positive electrode current collector and the negative electrode current collector, respectively. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6124894 [Patent Document 2] Japanese Patent Publication No. 2022-122592 Summary of the Invention [Problem to be solved by the invention]

[0008] A method for manufacturing a biplate having the above structure includes a first step of fixing a lead layer (one of the positive and negative current collector plates) to one surface of a substrate with an adhesive; a second step of inserting a conductor into the through hole of the substrate and performing resistance welding while an uncured adhesive layer is formed between the other surface of the substrate and the lead layer (the other of the negative and positive current collector plates); and a third step of curing the uncured adhesive layer and fixing a lead foil for the negative electrode to the other surface of the substrate.

[0009] In the second step, for example, the other side of the substrate, which has a current collector plate fixed to one side, is turned upward, a conductor is inserted into the through hole from above, and then resistance welding is performed while an uncured liquid adhesive layer is present on the other side (top surface) of the substrate in areas other than the through hole.

[0010] When this method is adopted, in the second step, the uncured liquid adhesive present around the through-hole may migrate to one side of the substrate through the gap between the conductor and the through-hole and reach the center of the end face of the conductor. As a result, the third step is carried out in a state where the end face of the conductor is contaminated with adhesive up to the center, which may reduce the bonding strength and reliability of the bonding between the two lead layers by the conductor.

[0011] The object of the present invention is to provide a biplate for a bipolar storage battery, which is produced by a method including the steps of: facing up the other surface of a substrate having a current collector plate fixed to one surface, inserting a conductor into a through hole from above, and then performing resistance welding in a state where an uncured liquid adhesive layer is present on the other surface (top surface) of the substrate except for the through hole; preventing the conductor from being contaminated with adhesive up to near the center of the end surface of the conductor; and ensuring the bonding strength of the conductor between the positive current collector plate and the negative current collector plate. [Means for solving the problem]

[0012] A first aspect of the present invention for solving the above problems is a biplate for a bipolar storage battery having the following configurations (1) to (5). (1) A bipolar storage battery includes a substrate disposed between two adjacent cell members, wherein a positive current collector plate constituting one of the cell members is fixed to one surface of the substrate with an adhesive, and a negative current collector plate constituting the other cell member is fixed to the other surface of the substrate with an adhesive. (2) The substrate has a substantially cylindrical through-hole extending in the thickness direction. A substantially cylindrical conductor is disposed in the through-hole. The substantially cylindrical shape includes a cylindrical shape (a cross-section perpendicular to the axial direction that is a perfect circle and a cross-section parallel to the axial direction that is a rectangle), a cross-section parallel to the axial direction that is rectangular like a cylinder, but the cross-section perpendicular to the axial direction is an ellipse or a shape in which a part of the perfect circle is crushed, a barrel shape (a cross-section parallel to the axial direction that is close to a rectangle, but a pair of opposing sides other than both axial ends are arc-shaped and convex outward), etc. (3) The conductor has a large diameter portion having a diameter corresponding to the diameter of the through hole (the same as or slightly smaller than the diameter of the through hole) and a small diameter portion having a diameter smaller than the large diameter portion, and the small diameter portion is formed on at least one of the axial ends of the conductor. (4) At least one of the two thickness-wise ends of the substrate has a recess formed by the outer peripheral surface of the small diameter portion, the step surface between the small diameter portion of the large diameter portion, and the inner wall surface of the through hole. (5) Both end surfaces of the conductor are joined to the positive electrode current collector plate and the negative electrode current collector plate, respectively.

[0013] A first aspect of the present invention is a biplate for a bipolar storage battery having the above configurations (1), (2), and (5) and the following configuration (6). (6) The approximately cylindrical body forming the conductor has a diameter corresponding to the diameter of the through hole (the same as or slightly smaller than the diameter of the through hole), and a recess is formed on at least one edge of both end faces of the conductor in the thickness direction of the substrate. [Effects of the Invention]

[0014] The biplate for a bipolar storage battery of the present invention is produced by a method including the steps of: facing up a substrate having a current collector fixed to one surface, inserting a conductor into a through hole from above, and then performing resistance welding in a state in which a liquid adhesive layer is present on the other surface of the substrate other than the through hole; it is expected that the conductor will be prevented from being contaminated with adhesive up to near the center of its end surface, and that the bonding strength of the conductor between the positive current collector and the negative current collector can be ensured. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a bipolar lead-acid battery according to a first embodiment. FIG. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] 1. FIG. 3 is a partially enlarged view of FIG. 2, illustrating the structure of a biplate that constitutes the bipolar lead-acid battery of FIG. [Figure 4] FIG. 4 is a diagram illustrating a recess formed by the through-hole in the substrate of the biplate and the conductor, and is a partially enlarged view in which the adhesive, active material layer, current collector, and separator in the recess are removed from FIG. 3. [Figure 5] 2 is a cross-sectional view illustrating a step of fixing a positive current collector plate to one surface of a biplate in a method for manufacturing the bipolar lead-acid battery of FIG. 1. FIG. [Figure 6] 2 is a cross-sectional view illustrating a step of attaching a negative electrode current collector plate to the other surface of the biplate in a method for manufacturing the bipolar lead-acid battery of FIG. 1. FIG. [Figure 7] FIG. 5 is a cross-sectional view showing the shape of a biplate for a bipolar storage battery according to a second embodiment. [Figure 8] 8 is a cross-sectional view illustrating a step of attaching a negative electrode current collector plate to the other surface of the biplate in the method of manufacturing the biplate for the bipolar storage battery of FIG. 7. FIG. [Figure 9] FIG. 10 is a cross-sectional view showing the shape of a biplate for a bipolar storage battery according to a third embodiment. [Figure 10] 10 is a cross-sectional view illustrating a step of attaching a negative electrode current collector plate to the other surface of the biplate, in the method of manufacturing the biplate for the bipolar storage battery of FIG. 9. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. In the following embodiments, limitations that are technically preferable for carrying out the present invention are imposed, but these limitations are not essential requirements of the present invention. In the following, a bipolar lead-acid battery will be described as an example of a bipolar storage battery.

[0017] [First embodiment] [Overall structure] First, the overall configuration of the bipolar lead-acid battery of this embodiment will be described. As shown in FIG. 1, the bipolar lead-acid battery 100 of this embodiment is composed of a main body 101 and a lid 190. FIG. 1 shows the installed state of the bipolar lead-acid battery 100 during the electrolyte injection process, and the up-down direction of the main body 101 in this state is the X direction. The lid 190 is fixed to one end face of the main body 101 in the X direction (the upper face during the electrolyte injection process). In other words, the lid 190 is disposed at a position that will be the upper side of the main body 101 during the electrolyte injection process. The lid 190 has electrolyte supply ports 191 at three locations along the Z direction at the center in the Y direction. Each electrolyte supply port 191 is disposed directly above one of the multiple injection ports formed in the main body 101 that is disposed at the center in the Y direction.

[0018] As shown in Fig. 2, the main body 101 has a plurality of cell members 110, a plurality of biplates (space-forming members) 120, a first end plate (space-forming member) 130, and a second end plate (space-forming member) 140. While Fig. 2 shows a bipolar lead-acid battery 100 in which three cell members 110 are stacked, the number of cell members 110 is determined by the battery design. In addition, the number of biplates 120 is determined according to the number of cell members 110.

[0019] The stacking direction of the cell members 110 is the Z direction (the vertical direction in FIG. 2), and the direction perpendicular to the paper surface of FIG. 2 is the Y direction. The cell member 110 includes a positive electrode 111, a negative electrode 112, and two stacked separators 113a and 113b. The positive electrode 111 includes positive electrode lead foils (positive electrode current collectors) 111a and 111aa and a positive electrode active material layer 111b. The negative electrode 112 includes negative electrode lead foils (negative electrode current collectors) 112a and 112aa and a negative electrode active material layer 112b. The two separators 113a and 113b are located between the positive electrode 111 and the negative electrode 112. In the cell member 110, the positive electrode lead foils 111a and 111aa, the positive electrode active material layer 111b, the two separators 113a and 113b, the negative electrode active material layer 112b, and the negative electrode lead foils 112a and 112aa are stacked in this order.

[0020] The dimension (thickness) in the Z direction of the positive electrode lead foil 111a is larger (thicker) than that of the negative electrode lead foil 112a, and the positive electrode active material layer 111b is larger (thicker) than that of the negative electrode active material layer 112b. The multiple cell members 110 are stacked and arranged at intervals in the Z direction, and the substrates 121 of the biplates 120 are arranged in these intervals. In other words, the multiple cell members 110 are stacked with the substrates 121 of the biplates 120 sandwiched between them.

[0021] The plurality of biplates 120, the first end plate 130, and the second end plate 140 are members (space forming members) for forming a plurality of spaces (cells) C that individually house a plurality of cell members 110. The biplate 120 comprises a substrate 121 having a rectangular planar shape, a frame 122 covering the four end faces of the substrate 121, and pillars 123 protruding perpendicularly from both sides of the substrate 121, and the substrate 121, frame 122, and pillars 123 are integrally formed from synthetic resin. The number of pillars 123 protruding from each side of the substrate 121 may be one or more.

[0022] 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. By stacking multiple biplates 120 with the frame bodies 122 and pillar portions 123 in contact with each other, a space C is formed between the substrates 121, and the dimension of the space C in the Z direction is maintained by the pillar portions 123 in contact with each other.

[0023] The substrate 121 of the biplate 120 has a plurality of cylindrical through-holes 121a extending in the thickness direction within its surface. The cylindrical bodies forming the through-holes 121a have their axial direction aligned with the thickness direction of the substrate 121. 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 first recess 121b is deeper than the second recess 121c. The dimensions in the X and Y directions of the first recess 121b and the second recess 121c correspond to the dimensions in the X and Y directions of the positive electrode lead foil 111a and the negative electrode lead foil 112a.

[0024] The substrate 121 of the biplate 120 is disposed between adjacent cell members 110 in the Z direction. The substrate 121 of the biplate 120 is a plate that covers both the positive electrode 111 side of one cell member 110 and the negative electrode 112 side of the adjacent cell member 110. The positive electrode lead foil 111a of the cell member 110 is disposed in a first recess 121b of the substrate 121 of the biplate 120 via an adhesive layer 150. In other words, the positive electrode lead foil 111a is fixed to the surface of the substrate 121 on the positive electrode 111 side (the bottom surface of the first recess 121b) with an adhesive.

[0025] Furthermore, the negative electrode lead foil 112a of the cell member 110 is placed in the second recess 121c of the substrate 121 of the biplate 120 via the adhesive layer 150. That is, the negative electrode lead foil 112a is fixed to the surface of the substrate 121 on the negative electrode 112 side (the bottom surface of the second recess 121c) with the adhesive.

[0026] A cylindrical conductor 160 is disposed in through-hole 121a of substrate 121 of biplate 120. As shown in Fig. 3, conductor 160 is composed of a cylindrical large-diameter portion 161 having substantially the same diameter as that of through-hole 121a (a diameter corresponding to the diameter of through-hole 121a), and a pair of cylindrical small-diameter portions 162a, 162b having a diameter smaller than that of large-diameter portion 161.

[0027] Then, by disposing the conductor 160 in the through hole 121a, annular recesses 170a, 170b are formed between the small diameter portions 162a, 162b and the through hole 121a. That is, as shown in Fig. 4, recesses 170a, 170b are formed at both ends in the thickness direction of the substrate 121 by outer circumferential surfaces 1621 of the small diameter portions 162a, 162b, step surfaces 1611 between the small diameter portions 162 of the large diameter portion 161, and the inner wall surface 1211 of the through hole 121a.

[0028] Adhesives 152 and 151 are present in the recesses 170a and 170b, and the adhesive 152 is continuous with the adhesive (adhesive layer 150) that fixes the positive electrode lead foil 111a to one surface of the substrate 121, and the adhesive 151 is continuous with the adhesive (adhesive layer 150) that fixes the negative electrode lead foil 112a to the other surface of the substrate 121. In other words, the recesses 170a and 170b contain the adhesives 152 and 151 that are continuous with the adhesive layer 150, respectively.

[0029] Furthermore, the end faces of the pair of small diameter portions 162a, 162b of the conductor 160 are in contact with and coupled to the positive electrode lead foil 111a and the negative electrode lead foil 112a, respectively. That is, the positive electrode lead foil 111a and the negative electrode lead foil 112a are connected by the conductor 160. As a result, all of the multiple cell members 110 are electrically connected in series.

[0030] The first end plate 130 comprises a substrate 131 that covers the positive electrode side of the cell member 110, a frame 132 that surrounds the side of the cell member 110, and pillars 133 that protrude perpendicularly from one surface of the substrate 131 (the surface facing the substrate 121 of the biplate 120 that is arranged closest to the positive electrode). The planar shape of the plate 131 is rectangular, and the four end surfaces of the substrate 131 are covered with the frame 132, with the substrate 131, frame 132, and pillars 133 being integrally formed from a synthetic resin. The number of pillars 133 protruding from one surface of the substrate 131 may be one or more, and they should correspond to the pillars 123 of the biplate 120 that come into contact with the pillars 133.

[0031] In the Z direction, the dimension of frame body 132 is larger than the dimension (thickness) of substrate 131, and the dimension between the protruding end faces of column portion 133 is the same as the dimension of frame body 132. By stacking frame body 132 and column portion 133 in contact with frame body 122 and column portion 123 of biplate 120 arranged on the outermost side (positive electrode side), a space C is formed between substrate 121 of biplate 120 and substrate 131 of first endplate 130, and the dimension of space C in the Z direction is maintained by column portion 123 of biplate 120 and column portion 133 of first endplate 130, which are in contact with each other.

[0032] A recess 131b is formed on one surface of the substrate 131 of the first end plate 130. The X-direction dimension of the recess 131b corresponds to the X-direction dimension of the positive electrode lead foil 111aa. The Z-direction dimension of the positive electrode lead foil 111aa arranged on one surface of the substrate 131 of the first end plate 130 is larger than the Z-direction dimension of the positive electrode lead foil 111a arranged on one surface of the substrate 121 of the biplate 120.

[0033] The positive electrode lead foil 111aa of the cell member 110 is placed in the recess 131b of the substrate 131 of the first end plate 130 via the adhesive layer 150. That is, the positive electrode lead foil 111aa is fixed to the surface of the substrate 131 on the positive electrode 111 side (the bottom surface of the recess 131b) with the adhesive. The first end plate 130 also includes a positive electrode terminal electrically connected to the positive electrode lead foil 111aa in the recess 131b.

[0034] The second end plate 140 is composed of a plate (hereinafter referred to as the "substrate") 141 that covers the negative electrode side of the cell member 110, a frame 142 that surrounds the side of the cell member 110, and pillars 143 that protrude vertically from one surface of the substrate 141 (the surface facing the substrate 121 of the biplate 120 that is arranged on the most negative electrode side). The planar shape of the substrate 141 is rectangular, and the four end surfaces of the substrate 141 are covered with the frame 142, and the substrate 141, frame 142, and pillars 143 are integrally formed from a synthetic resin. The number of pillars 143 protruding from one surface of the substrate 141 may be one or more, and they should correspond to the pillars 123 of the biplate 120 that come into contact with the pillars 143.

[0035] In the Z direction, the dimension of frame body 142 is larger than the dimension (thickness) of substrate 131, and the dimension between the protruding end faces of two pillar portions 143 is the same as the dimension of frame body 142. By stacking frame body 142 and pillar portions 143 in contact with frame body 122 and pillar portions 123 of biplate 120 arranged on the outermost side (negative electrode side), a space C is formed between substrate 121 of biplate 120 and substrate 141 of second end plate 140, and the dimension of space C in the Z direction is maintained by pillar portions 123 of biplate 120 and pillar portions 143 of second end plate 140, which are in contact with each other.

[0036] A recess 141b is formed on one surface of the substrate 141 of the second end plate 140. The X and Y dimensions of the recess 141b correspond to the X and Y dimensions of the negative electrode lead foil 112aa. The Z dimension of the negative electrode lead foil 112aa arranged on one surface of the substrate 141 of the second end plate 140 is larger than the Z dimension of the negative electrode lead foil 112a arranged on the other surface of the substrate 121 of the biplate 120.

[0037] The negative electrode lead foil 112aa of the cell member 110 is placed in the recess 141b of the substrate 141 of the second end plate 140 via the adhesive layer 150. That is, the negative electrode lead foil 112aa is fixed to the surface of the substrate 141 on the negative electrode 112 side (the bottom surface of the recess 141b) with the adhesive.

[0038] The second end plate 140 also includes a negative electrode terminal electrically connected to the negative electrode lead foil 112aa in the recess 141b.

[0039] Furthermore, the positive electrode lead foils 111a, 111aa, the positive electrode active material layer 111b, the negative electrode lead foils 112a, 112aa, the negative electrode active material layer 112b, and the two separators 113a, 113b are respectively formed with holes (hereinafter referred to as "insertion holes") 111c, 111d, 112c, 112d, 113c penetrating through the thickness direction for inserting the corresponding column portions 123, 133, 143. The corresponding column portions 123, 133, 143 are inserted into the insertion holes 111c, 111d, 112c, 112d, 113c.

[0040] Furthermore, the opposing surfaces of adjacent frame bodies 122, 132, 142 are joined by vibration welding, and the biplate 120, first end plate 130, and second end plate 140 are integrated together. As can be seen from the above description, the biplate 120 is a space-forming member that includes a substrate 121, which is a plate that covers both the positive electrode side and the negative electrode side of the cell member 110, and a frame 122 that surrounds the side surface of the cell member 110. The first end plate 130 is a space-forming member that includes a substrate 131 that covers only the positive electrode side (either the positive electrode side or the negative electrode side) of the cell member 110, and a frame 132 that surrounds the side surface of the cell member 110.

[0041] The second end plate 140 is a space-forming member that includes a substrate 141, which is a plate that covers only the negative electrode side (either the positive electrode side or the negative electrode side) of the cell member 110, and a frame 142 that surrounds the side surface of the cell member 110. In other words, the substrate 121 and the substrates 131, 141 are plates that cover at least one of the positive electrode side and the negative electrode side of the cell member 110. The substrate 121 of the biplate 120 is disposed between the cell members 110.

[0042] [Manufacturing method] The bipolar lead-acid battery 100 of this embodiment can be manufactured, for example, by a method including the steps described below.

[0043] <Production process of biplate with lead foil for positive and negative electrodes> First, as shown in Fig. 5(a), the substrate 121 of the biplate 120 is placed on a workbench with the first recess 121b facing upward. Next, adhesive is applied to one surface of the positive electrode lead foil 111a. At this time, a mold in which the portion corresponding to the through hole 121a is masked is used so that the adhesive is not applied to the portion corresponding to the through hole 121a.

[0044] Next, the positive electrode lead foil 111a is placed into the first recess 121b with the adhesive-coated side facing downward. At this time, the column portion 123 of the biplate 120 is passed through the insertion hole 111c of the positive electrode lead foil 111a. Figure 5(b) shows this state. Next, the adhesive is hardened to form an adhesive layer 150. This allows the positive electrode lead foil 111a to be attached to one surface of the substrate 121.

[0045] 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 so that one end surface (lower end surface) of the conductor 160 contacts the positive electrode lead foil 111a. Figure 6(a) shows this state. In this state, the large diameter portion 161 of the conductor 160 is in contact with the through-hole 121a, or there is a small gap between them. In addition, an annular recess 170a is formed between the small diameter portion 162b and the through-hole 121a, and an annular recess 170b is formed between the through-hole 121a and the small diameter portion 162a.

[0046] Next, adhesive is applied to one surface of the negative electrode lead foil 112a. At this time, a mold in which the portion corresponding to the through hole 121a is masked is used so that the adhesive is not applied to the portion corresponding to the through hole 121a.

[0047] Next, the negative electrode lead foil 112a is inserted into the second recess 121c with the adhesive-coated side facing downward. At this time, the column portion 123 of the biplate 120 is passed through the insertion hole 112c of the negative electrode lead foil 112a. At this time, the adhesive applied near the through-hole 121a may fall due to the attachment pressure, but even in this case, the fallen adhesive is trapped in the annular recess 170b formed between the through-hole 121a and the small-diameter portion 162a. Figure 6(b) shows this state. Reference numeral 151 denotes the adhesive trapped in the recess 170b. Reference numeral 150a denotes the adhesive layer before hardening.

[0048] Next, resistance welding is performed. At this time, the welding tip pinches and presses the positive lead foil 111a and the negative lead foil 112a directly above and below the conductor 160, so that the positive lead foil 111a and the negative lead foil 112a are pressed toward the conductor 160 and deformed, and the negative lead foil 112a comes into contact with the upper end surface of the conductor 160, whose lower end surface is in contact with the positive lead foil 111a.

[0049] Next, the uncured adhesive layer 150a is cured to form the adhesive layer 150. As a result, the negative electrode lead foil 112a is fixed to the other surface of the substrate 121. In this way, a biplate 120 (a biplate with positive and negative lead foils) is obtained in which the positive lead foil 111a and the negative lead foil 112a are fixed to both sides of the substrate 121 with an adhesive and the positive lead foil 111a and the negative lead foil 112a are joined by the conductor 160. The required number of such biplates with positive and negative lead foils are prepared.

[0050] <Process for manufacturing end plates with lead foil for the positive electrode> The plate 131 of the first end plate 130 is placed on a workbench with the recess 131b facing up, adhesive is applied to the recess 131b, and the positive electrode lead foil 111aa is inserted into the recess 131b. At this time, the post portions 133 of the end plate 130 are passed through the insertion holes 111c of the positive electrode lead foil 111aa. The adhesive is cured to form an adhesive layer 150. This results in a first end plate 130 (an end plate with positive electrode lead foil) in which the positive electrode lead foil 111aa is fixed to one surface of the plate 131.

[0051] <Process for manufacturing end plates with lead foil for negative electrodes> The substrate 141 of the second end plate 140 is placed on a workbench with the recess 141b facing up, adhesive is applied to the recess 141b, and the negative electrode lead foil 112aa is inserted into the recess 141b. At this time, the column portions 143 of the second end plate 140 are passed through the insertion holes 112c of the negative electrode lead foil 112aa. The adhesive is cured to form an adhesive layer 150. This results in a second end plate 140 (an end plate with a negative electrode lead foil) in which the negative electrode lead foil 112aa is fixed to one surface of the substrate 141.

[0052] <The process of stacking and joining plates> First, the first end plate 130 to which the positive electrode lead foil 111a is fixed is placed on a workbench with the positive electrode lead foil 111a facing upward, and the positive electrode active material layer 111b is placed on the positive electrode lead foil 111a. At this time, the column portions 133 of the first end plate 130 are passed through the insertion holes 111d of the positive electrode active material layer 111b. Next, the separators 113a and 113b and the negative electrode active material layer 112b are placed in this order on the positive electrode active material layer 111b.

[0053] Next, the biplate 120 with the positive and negative electrode lead foils is placed with the negative electrode lead foil 112a side facing downward on the first end plate 130 in this state. At this time, the column parts 123 of the biplate 120 are passed through the insertion holes 113c of the separators 113a and 113b and the insertion hole 112d of the negative electrode active material layer 112b, and placed on the column parts 133 of the first end plate 130, and the frame 122 of the biplate 120 is placed on the frame 132 of the first end plate 130.

[0054] In this state, first end plate 130 is fixed, and vibration welding is performed while vibrating biplate 120 in the diagonal direction of substrate 121. As a result, frame 122 of biplate 120 is joined onto frame 132 of first end plate 130, and column portions 123 of biplate 120 are joined onto column portions 133 of first end plate 130.

[0055] As a result, the biplate 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 biplate 120, and the positive electrode lead foil 111a is exposed on the upper surface of the biplate 120.

[0056] Next, the positive electrode active material layer 111b, separators 113a, 113b, and negative electrode active material layer 112b are placed in this order on the combined assembly thus obtained, in which the biplate 120 is joined to the first end plate 130, and then another biplate 120 with positive and negative electrode lead foils is placed with the negative electrode lead foil 112a side facing downwards.

[0057] In this state, the combined body is fixed, and vibration welding is performed while vibrating the biplate 120 with the lead foils for the positive and negative electrodes in the diagonal direction of the substrate 121. This vibration welding process is continued until the required number of biplates 120 are joined onto the first end plate 130.

[0058] Finally, the positive electrode active material layer 111b, separators 113a, 113b, and negative electrode active material layer 112b are placed in this order on the uppermost biplate 120 of the combined assembly in which all the biplates 120 are joined, and then a second end plate 140 is placed with the negative electrode lead foil 112aa side facing downwards.

[0059] 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 onto the uppermost biplate 120 of the combined body to which all the biplates 120 have been joined.

[0060] By carrying out the above steps, the cell members and the substrates of the space forming members are alternately stacked, the cell members are electrically connected in series, and the opposing surfaces of adjacent frames are joined together. In other words, the structural part of the main body 101 can be assembled. In the above explanation, the stacking order is described as being from the first end plate 130 to the second end plate 140, but the stacking order may also be reversed, from the second end plate 140 to the first end plate 130.

[0061] <Other processes> The main body 101 assembled as described above is placed with the surface on which the liquid inlet is formed (one end surface in the X direction) facing up, and the lid 190 is placed on top of it so that the electrolyte supply port 191 is aligned with the liquid inlet at the center of the main body 101 in the Y direction, and the lid 190 is fixed to the main body 101. This results in the state shown in FIG.

[0062] Next, in the state shown in FIG. 1, the electrolyte is supplied from each of the electrolyte supply ports 191 of the lid 190. Finally, the bipolar lead-acid battery 100 is obtained by forming the battery under predetermined conditions.

[0063] [Action, effect] The manufacturing method described above employs a process in which the positive electrode lead foil 111a is fixed to the recess (one end surface in the thickness direction) 121b of the substrate 121 with adhesive (the liquid adhesive is hardened), and then the negative electrode lead foil 112a is attached to the recess (the other end surface in the thickness direction) 121c of the substrate 121 with adhesive, and the adhesive is hardened after resistance welding.

[0064] According to the bipolar lead-acid battery 100 of the embodiment, even if the liquid adhesive passes between the through-hole 121a and the conductor 160 and moves to the opposite side due to the pressing force during the attaching process and resistance welding process of the negative electrode lead foil 112a, the adhesive (indicated by reference numeral 152 in FIGS. 3 and 6(b)) is contained in the recess 170a formed between the small diameter portion 162b and the through-hole 121a, and therefore the adhesive can be prevented from reaching the vicinity of the center of the conductor 160 in plan view. As a result, the contact area between both end surfaces of the conductor 160 and the positive electrode lead foil 111a and the negative electrode lead foil 112a is secured, and the joining strength by resistance welding can be secured.

[0065] In contrast, if the recess 170a were not present, the liquid adhesive 152 that passes between the through hole and the conductor and moves to the other side would penetrate between the conductor and the positive electrode lead foil 111a, reaching near the center of the conductor in a planar view, which would likely result in insufficient joint strength due to resistance welding.

[0066] Furthermore, since the recesses 170a and 170b contain the adhesives 152 and 151 that are continuous with the adhesive layer 150, respectively, it is expected that there will be an effect of suppressing liquid junctions caused by the electrolyte seeping up.

[0067] Furthermore, in the manufacturing process of the biplate 120, if a process is adopted in which the negative electrode lead foil 112a is fixed to the recess 121c of the substrate 121 with adhesive (the liquid adhesive is hardened), and then the positive electrode lead foil 111a is attached to the recess 121b of the substrate 121 with adhesive, and the adhesive is hardened after resistance welding, the liquid adhesive that passes between the through hole 121a and the conductor 160 due to the pressing force and moves to the opposite side during the process of attaching the positive electrode lead foil 111a and the resistance welding process is contained in the recess 170b formed between the small diameter portion 162b and the through hole 121a, and is prevented from reaching the center of the conductor 160.

[0068] That is, in the bipolar lead-acid battery 100 of this embodiment, the conductor 160 has a shape including a large diameter portion 161 and a pair of small diameter portions 162a, 162b, so that in the manufacturing process of the biplate 120, it is not necessary to consider the direction in which the conductor 160 is inserted into the through-hole 121a, regardless of whether the positive electrode lead foil 111a or the negative electrode lead foil 112a is bonded to the substrate 121 first. Therefore, an effect of improving the working efficiency in the manufacturing process of the biplate 120 is obtained.

[0069] [Second embodiment] The bipolar lead-acid battery of the second embodiment is the same as the bipolar lead-acid battery 100 of the first embodiment, except that a conductor 160A having the shape shown in FIG. 7 is used instead of the conductor 160 having the shape shown in FIG.

[0070] As shown in FIG. 7, the conductor 160A is cylindrical with a diameter substantially the same as that of the through-hole 121a (a diameter corresponding to the diameter of the through-hole 121a), and has an annular recess 160a formed at the edge of one axial end face.

[0071] Moreover, adhesive 152a is present in the recess 160a, and the adhesive 152a is continuous with the adhesive (adhesive layer 150) that fixes the positive electrode lead foil 111a to one surface of the substrate 121. In other words, the recess 160a contains adhesive 152a that is continuous with the adhesive (adhesive layer 150).

[0072] One axial end face of the conductor 160A (the end face where the recess 160a is formed) is joined to the positive electrode lead foil 111a, and the other end face is joined to the negative electrode lead foil 112a. As a result, all of the multiple cell members 110 are electrically connected in series.

[0073] <Production process of biplate with lead foil for positive and negative electrodes> As in the first embodiment, after achieving the state shown in FIG. 5(b), the adhesive is cured to form the adhesive layer 150. This causes the positive electrode lead foil 111a to be attached to one surface of the substrate 121. Next, the substrate 121 is placed on a workbench with the second recess 121c side facing upward, and the conductor 160A is inserted into the through hole 121a so that one end surface (lower end surface) of the conductor 160 is brought into contact with the positive electrode lead foil 111a. FIG. 8(a) shows this state. In this state, the conductor 160B is in contact with the through hole 121a, or there is a small gap between them.

[0074] Next, adhesive is applied to one surface of the negative electrode lead foil 112a. At this time, a mold in which the portion corresponding to the through hole 121a is masked is used so that the adhesive is not applied to the portion corresponding to the through hole 121a.

[0075] Next, the negative electrode lead foil 112a is inserted into the second recess 121c with the adhesive-coated side facing downward. At this time, the column 123 of the biplate 120 is passed through the insertion hole 112c of the negative electrode lead foil 112a. At this time, the adhesive applied near the through-hole 121a may fall off due to the application pressure. However, even in this case, the fallen adhesive is divided into two parts: one that rests on the edge of the conductor 160A (adhesive 153) and the other that passes between the through-hole 121a and the conductor 160A and moves to the opposite side (wraps around under the edge) (adhesive 152). Figure 8(b) shows this state. Reference numeral 150a denotes the adhesive layer before hardening.

[0076] Next, resistance welding is performed. At this time, the welding tip pinches the positive electrode lead foil 111a and the negative electrode lead foil 112a directly above and below the conductor 160A and presses them together, causing the positive electrode lead foil 111a and the negative electrode lead foil 112a to be pressed toward the conductor 160A and deformed, and the negative electrode lead foil 112a comes into contact with the upper end surface of the conductor 160A, whose lower end surface is in contact with the positive electrode lead foil 111a. At this time, a portion of the adhesive 152 that has slipped under the edge of the conductor 160A is accommodated in the recess 160a.

[0077] Next, the uncured adhesive layer 150a is cured to form the adhesive layer 150. As a result, the negative electrode lead foil 112a is fixed to the other surface of the substrate 121. In this way, a biplate 120 (a biplate with positive and negative lead foils) is obtained in which the positive lead foil 111a and the negative lead foil 112a are fixed to both sides of the substrate 121 with an adhesive and the positive lead foil 111a and the negative lead foil 112a are joined by the conductor 160A. The required number of such biplates with positive and negative lead foils are prepared.

[0078] <Actions and Effects> 7, a portion 152a of the adhesive 152 that passes between the through-hole 121a and the conductor 160A and moves to the opposite side and wraps around under the edge of the conductor 160A is accommodated in the recess 160a, preventing the adhesive from reaching the center of the conductor 160A in plan view. As a result, a sufficient contact area is secured between both end faces of the conductor 160A and the positive electrode lead foil 111a and the negative electrode lead foil 112a, ensuring sufficient joint strength by resistance welding.

[0079] Furthermore, since the recess 160a contains the adhesive 152a that is continuous with the adhesive layer 150, it is expected that there will be an effect of suppressing liquid junctions caused by the electrolyte seeping up.

[0080] [Third embodiment] The bipolar lead-acid battery of the second embodiment is the same as the bipolar lead-acid battery 100 of the first embodiment except that the conductor 160B having the shape shown in FIG. 9 is used instead of the conductor 160 having the shape shown in FIG.

[0081] 9, conductor 160B is composed of a cylindrical large-diameter portion 161 having a diameter substantially the same as that of cylindrical through-hole 121a, and a cylindrical small-diameter portion 162 having a diameter smaller than that of through-hole 121a. The axial dimension of the cylinder forming small-diameter portion 162 is approximately one-sixth of the axial dimension of the cylinder forming conductor 160B. The axial dimension of the cylinder forming large-diameter portion 161 is approximately five-sixths of the axial dimension of the cylinder forming conductor 160B.

[0082] An annular recess 161a is formed on the edge of the end face of the large diameter portion 161 on one axial end side (opposite to the small diameter portion 162). Furthermore, by arranging the conductor 160B in the through hole 121a, an annular recess 170c is formed between the small diameter portion 162 and the through hole 121a, similar to the recess 171a of the first embodiment described in Figure 4.

[0083] Moreover, adhesives 152 and 151 are present in the recesses 170c and 161a, and the adhesive 152 is continuous with the adhesive (adhesive layer 150) that fixes the positive electrode lead foil 111a to one surface of the substrate 121, and the adhesive 151 is continuous with the adhesive (adhesive layer 150) that fixes the negative electrode lead foil 112a to the other surface of the substrate 121. In other words, the recesses 170c and 161a contain the adhesives 152 and 151 that are continuous with the adhesive layer 150, respectively.

[0084] The positive electrode lead foil 111a and the negative electrode lead foil 112a are connected by the conductor 160B, so that all of the cell members 110 are electrically connected in series.

[0085] <Production process of biplate with lead foil for positive and negative electrodes> As in the first embodiment, after achieving the state shown in FIG. 5(b), the adhesive is cured to form the adhesive layer 150. This attaches the positive electrode lead foil 111a to one surface of the substrate 121. Next, the substrate 121 is placed on a workbench with the second recess 121c facing upward, and the conductor 160B is inserted into the through-hole 121a so that one end surface (lower end surface) of the conductor 160B contacts the positive electrode lead foil 111a. FIG. 10(a) shows this state. In this state, the large diameter portion 161 of the conductor 160B is in contact with the through-hole 121a, or there is a small gap between them.

[0086] Next, adhesive is applied to one surface of the negative electrode lead foil 112a. At this time, a mold in which the portion corresponding to the through hole 121a is masked is used so that the adhesive is not applied to the portion corresponding to the through hole 121a.

[0087] Next, the negative electrode lead foil 112a is inserted into the second recess 121c with the adhesive-coated side facing downward. At this time, the column 123 of the biplate 120 is passed through the insertion hole 112c of the negative electrode lead foil 112a. At this time, the adhesive applied near the through-hole 121a may fall off due to the application pressure. However, even in this case, the fallen adhesive is divided into two parts: one that rests on the edge of the conductor 160B (adhesive 153) and the other that passes between the through-hole 121a and the conductor 160B and moves to the opposite side (adhesive 152). The part of the adhesive 153 that rests on the edge of the conductor 160B enters the recess 161a (adhesive 151). The adhesive 152 that has moved to the opposite side enters the lower recess 170c. Figure 10(b) shows this state. Reference numeral 150a denotes the adhesive layer before hardening.

[0088] Next, resistance welding is performed. At this time, the welding tip pinches and presses the positive lead foil 111a and the negative lead foil 112a directly above and below the conductor 160B, so that the positive lead foil 111a and the negative lead foil 112a are pressed toward the conductor 160B and deformed, and the negative lead foil 112a comes into contact with the upper end surface of the conductor 160B, whose lower end surface is in contact with the positive lead foil 111a.

[0089] Next, the uncured adhesive layer 150a is cured to form the adhesive layer 150. As a result, the negative electrode lead foil 112a is fixed to the other surface of the substrate 121. In this way, the positive electrode lead foil 111a and the negative electrode lead foil 112a are fixed to both sides of the substrate 121 with an adhesive, and the positive electrode lead foil 111a and the negative electrode lead foil 112a are joined by the conductor 160B to obtain a biplate 120 (a biplate with positive and negative electrode lead foils). The required number of such biplates with positive and negative electrode lead foils are prepared.

[0090] <Actions and Effects> 9, when the negative electrode lead foil 112a is attached, a portion 151 of the adhesive 153 placed on the edge of the conductor 160B is accommodated in the recess 161a, and the adhesive 152 that passes between the through hole 121a and the conductor 160B and moves to the opposite side is accommodated in the recess 170c, preventing the adhesive from reaching the vicinity of the center of the conductor 160B in plan view. As a result, a sufficient contact area is secured between both end faces of the conductor 160B and the positive electrode lead foil 111a and the negative electrode lead foil 112a, ensuring sufficient joint strength by resistance welding.

[0091] Furthermore, since the adhesives 152 and 151 that are continuous with the adhesive layer 150 are respectively placed in the recesses 170c and 161a, it is expected that there will be an effect of suppressing liquid junctions caused by the electrolyte seeping up.

[0092] [others] Another example of the shape of the conductor is conductor 160A in Figure 7, which has an annular recess on the opposite side of the end face where the annular recess 160a is located, and the position of the recess does not completely overlap the position of recess 160a, and is located as far away as possible from the center of the bottom surface of the cylindrical body that forms the conductor.

[0093] In addition, in this embodiment, a bipolar lead-acid battery using lead for the current collector plate has been described as an example of a bipolar storage battery, but the bipolar storage battery of the present invention may also be a bipolar storage battery using a metal other than lead for the current collector plate. [Explanation of symbols]

[0094] 100 Bipolar lead-acid battery (bipolar battery) 101 Main Unit 110 Cell member 111 Positive electrode 112 Negative electrode 111a Positive lead foil (positive current collector plate) 112a Lead foil for negative electrode (negative electrode current collector plate) 111b Positive electrode active material layer 112b Negative electrode active material layer 113a Separator 113b Separator 120 Biplate (space forming member) 121 Biplate substrate 121a Through hole 121b First recess of substrate 121c second recess in the substrate 1211 Inner wall surface of through hole 122 Biplate frame 130 First end plate (space forming member) 131 First end plate substrate 132 First end plate frame 140 Second end plate (space forming member) 141 Second end plate substrate 142 Second end plate frame 150 Adhesive layer 150a Adhesive layer before curing 151 Adhesive trapped in the recess of the conductor 152 Adhesive that has passed between the through hole and the conductor and migrated to the other side 153 Adhesive on the edge of a conductor 160 Conductor 161 Large diameter section 161a Recess 162a Small diameter section 162b Small diameter section 1621 Outer surface of small diameter part 1611 Step surface between large diameter part and small diameter part 170a Recess 170b recess 190 Lid 191 Electrolyte supply port C. Space for accommodating cell components

Claims

1. A bipolar storage battery includes a substrate disposed between two adjacent cell members, a positive electrode current collector plate constituting one of the cell members is fixed to one surface of the substrate with an adhesive, and a negative electrode current collector plate constituting the other cell member is fixed to the other surface of the substrate with an adhesive; the substrate has a substantially cylindrical through-hole extending in a thickness direction, A substantially cylindrical conductor is disposed in the through hole, the conductor includes a large diameter portion having a diameter corresponding to the diameter of the through hole and a small diameter portion having a diameter smaller than that of the large diameter portion, the small diameter portion is formed on at least one of the axial ends of the conductor; a recess formed on at least one of both end portions in the thickness direction of the substrate by an outer circumferential surface of the small diameter portion, a step surface between the small diameter portion of the large diameter portion and the small diameter portion, and an inner wall surface of the through hole; a biplate for a bipolar storage battery, wherein both end faces of the conductor are joined to the positive electrode current collector plate and the negative electrode current collector plate, respectively;

2. A bipolar storage battery includes a substrate disposed between two adjacent cell members, a positive electrode current collector plate constituting one of the cell members is fixed to one surface of the substrate with an adhesive, and a negative electrode current collector plate constituting the other cell member is fixed to the other surface of the substrate with an adhesive; the substrate has a substantially cylindrical through-hole extending in a thickness direction, A substantially cylindrical conductor is disposed in the through hole, the substantially cylindrical body forming the conductor has a diameter corresponding to the diameter of the through hole, a recess formed in an edge portion of at least one of both axial ends of the conductor; a biplate for a bipolar storage battery, wherein both end faces of the conductor are joined to the positive electrode current collector plate and the negative electrode current collector plate, respectively;

3. 3. The biplate for a bipolar storage battery according to claim 1 or 2, wherein an adhesive is present in the recess, and the adhesive present in the recess is continuous with an adhesive that fixes the positive current collector plate to one surface of the substrate or an adhesive that fixes the negative current collector plate to the other surface of the substrate.

4. A bipolar storage battery comprising the biplate for a bipolar storage battery according to claim 1 or 2.

5. 5. The bipolar storage battery according to claim 4, wherein the positive electrode current collector or the negative electrode current collector is made of lead or a lead alloy.

6. A bipolar storage battery comprising the biplate for a bipolar storage battery according to claim 3.

7. 7. The bipolar storage battery according to claim 6, wherein the positive electrode current collector or the negative electrode current collector is made of lead or a lead alloy.

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