Bipolar storage battery and manufacturing method of bipolar storage battery

Abstract

To prevent a tab portion of a collector connected to a terminal so as to be provided to an end plate from reducing a battery performance by suppressing corrosion in a region of the tab portion arranged in an internal part of a power storage battery, and increase the life.SOLUTION: A positive electrode active material layer 111b and a current collector 111a or a negative electrode active material layer 112b and a current collector 112a are provided with a pair of end plates 130 sandwiching a separator 113 so as to be stacked, and each end plate 130 includes a substrate 131 provided with the positive electrode active material layer 111b and a current collector 111aa and a frame 132 surrounding side surfaces of the positive electrode active material layer 111b and the current collector 111aa. The current collector 111aa includes a tab portion 11 that protrudes outward from an inside of the frame body 132 in which the current collector 111aa is disposed and is electrically connected to a positive electrode terminal component 160, and a liquid seepage prevention member 180 is provided in at least a part of the tab portion 11 between the peripheral edge portion of the current collector 111aa and the outside of the frame body 132.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to a bipolar battery and a method for manufacturing a bipolar 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] One example of the structure of such a lead-acid battery is one in which a resin substrate (bipolar plate) is attached to the inside of a frame (rim) made of resin in the shape of a picture frame. A positive electrode lead layer and a negative electrode lead layer are provided on one and the other sides of the substrate of this lead-acid battery. A positive electrode active material layer is adjacent to the positive electrode lead layer. A negative electrode active material layer is adjacent to the negative electrode lead layer. A glass mat (electrolytic layer) containing an electrolyte is disposed inside a frame-shaped resin spacer. A plurality of frames and spacers are alternately stacked and assembled.

[0004] That is, this lead-acid battery has 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) interposed 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] Furthermore, some lead-acid batteries are provided with a protective case, in which a portion of the frame surrounding one side of the cell member is covered with a lid, and an electrode receiving space is formed between the lid and the battery body. The tip of the lug of the current collector plate constituting the cell member arranged at one end in the stacking direction is bent, and this bent portion is connected to a terminal protruding from the lid to the outside in the electrode receiving space.

[0006] However, in the example of the lead-acid battery equipped with a protective case, as described above, the bent portion of the lug of the current collector constituting the cell member arranged at one end in the stacking direction is connected to the terminal protruding from the lid in the electrode receiving space. Therefore, as the electrolyte flows through the current collector due to capillary action and reaches the electrode receiving space, the connection portion with the terminal lug may corrode, resulting in a deterioration in battery performance (e.g., a shortened lifespan, an increased internal resistance, and a decreased battery capacity). To address this problem, the applicant developed a bipolar storage battery, as shown in Patent Document 1 below, in which the connection portion of the terminal with the lug of the current collector plate is resistant to corrosion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2023 / 054524 Summary of the Invention [Problem to be solved by the invention]

[0008] In the bipolar storage battery described in Patent Document 1, the current collector (lead foil) attached to the outermost end plate of the bipolar storage battery has a portion exposed to the outside of the bipolar storage battery. When welding the lid, the exposed portion is bent and welded to the positive or negative electrode terminal, and then filled with resin. This process allows the electrolyte to flow through the current collector by capillary action and reach the electrode receiving space, preventing corrosion of the connection with the current collector lug and a resulting decrease in battery performance.

[0009] On the other hand, for example, during the manufacturing process of a bipolar storage battery, when an electrolytic solution is injected and then chemical formation is performed, corrosion may occur in the ear portion of the current collector, which is the area that is located inside the bipolar storage battery.

[0010] The above-mentioned Patent Document 1 merely prevents corrosion on the lugs of the current collector exposed to the outside of the bipolar storage battery, and does not contribute to preventing corrosion on the lugs of the current collector arranged inside the bipolar storage battery.

[0011] The present invention aims to provide a bipolar storage battery and a method for manufacturing a bipolar storage battery that are less likely to experience a decline in battery performance and can achieve a longer lifespan by suppressing corrosion in the area of ​​the tab portion of a current collector that is provided on an end plate and connected to a terminal and that is located inside the storage battery. [Means for solving the problem]

[0012] A bipolar storage battery according to one aspect of the present invention includes a positive electrode active material layer, a negative electrode active material layer, a current collector in contact with either the positive electrode active material layer or the negative electrode active material layer, or both, a separator disposed between the positive electrode active material layer and the negative electrode active material layer facing each other, and a pair of end plates sandwiching a plurality of stacked positive electrode active material layers and current collectors, or a plurality of stacked negative electrode active material layers and current collectors, and separators, and the end plates are configured to sandwich the positive electrode active material layer and current collector, Alternatively, the present invention has a substrate having either a negative electrode active material layer and a current collector, and a frame surrounding the side surfaces of the positive electrode active material layer and the current collector, or the negative electrode active material layer and the current collector, wherein the current collector provided on the substrate has a tab portion that protrudes from the inside of the frame on which the current collector is arranged toward the outside of the frame and is electrically connected to a terminal for extracting electricity to the outside, and a liquid seepage prevention member is provided on at least a part of the tab portion between the peripheral edge of the current collector and the outside of the frame.

[0013] A method for manufacturing a bipolar storage battery according to one embodiment of the present invention includes the steps of: fabricating a pair of end plates by placing a current collector on an end plate substrate with a tab portion formed on the current collector penetrating a tab insertion hole formed in the substrate; providing a liquid-wicking prevention member on at least a portion of one or both of the pair of end plates, between the peripheral edge of the current collector in the tab portion and the outside of the frame of the end plate; arranging a first active material layer so that it is in contact with the current collector placed on one of the end plates with the liquid-wicking prevention member provided; arranging a separator so that it is in contact with the first active material layer; arranging a second active material layer so that it is in contact with the separator; and arranging a current collector so that it is in contact with the second active material layer; repeating the steps of stacking the first active material layer, the separator, the second active material layer, and the current collector until desired performance is obtained; and arranging the other end plate obtained in the end plate fabrication step. [Effects of the Invention]

[0014] According to the present invention, a bipolar storage battery according to one aspect of the present invention includes a positive electrode active material layer, a negative electrode active material layer, a current collector in contact with either the positive electrode active material layer or the negative electrode active material layer, or both, a separator disposed between the positive electrode active material layer and the negative electrode active material layer facing each other, and a pair of end plates sandwiching a plurality of stacked positive electrode active material layers and current collectors, or a plurality of stacked negative electrode active material layers and current collectors, and separators, and the end plates are The bipolar battery includes a substrate including a current collector, or a negative electrode active material layer and a current collector, and a frame surrounding the side surfaces of the positive electrode active material layer and current collector, or the negative electrode active material layer and current collector, wherein the current collector provided on the substrate includes a tab portion that protrudes from the inside of the frame where the current collector is disposed toward the outside of the frame and is electrically connected to a terminal for extracting electricity, and at least a portion of the tab portion is provided with a liquid seepage prevention member between the peripheral edge of the current collector and the outside of the frame. The bipolar battery employs this configuration, and by suppressing corrosion in the region of the tab portion of the current collector that is provided on the end plate and connected to the terminal and that is disposed inside the battery, it is possible to reduce deterioration in battery performance and achieve a longer lifespan. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view showing an outline of the structure of a bipolar storage battery according to an embodiment of the present invention. [Figure 2] 1A and 1B are schematic diagrams of an end plate according to a first embodiment of the present invention, in which (A) is a plan view and (B) is a side view of the end plate as seen from the direction of M. FIG. [Figure 3] 1A and 1B are schematic diagrams showing a state in which a current collector is arranged on an end plate according to a first embodiment of the present invention, in which (A) is a plan view and (B) is a side view of the end plate as seen from the direction M. FIG. [Figure 4] 1A and 1B show a state in which a liquid seepage prevention member is provided on a current collector arranged on an end plate according to a first embodiment of the present invention, where FIG. 1A is a plan view and FIG. 1B is an enlarged view showing the area indicated by the dashed circle in the plan view of FIG. 1A. [Figure 5] 1A and 1B show a state in which another type of liquid seepage prevention member is provided on a current collector arranged on an end plate according to a first embodiment of the present invention, where FIG. 1A is a plan view and FIG. 1B is an enlarged view of the area indicated by the dashed circle in the plan view of FIG. [Figure 6] 1A and 1B show a state in which a liquid seepage prevention member of another embodiment is provided on a current collector arranged on an end plate according to the first embodiment of the present invention, where (A) is a plan view and (B) is an enlarged view showing the area indicated by the dashed circle in the plan view of (A). [Figure 7] 5A and 5B are schematic diagrams of an end plate according to a second embodiment of the present invention, in which (A) is a plan view and (B) is a side view of the end plate as seen from the direction M. FIG. [Figure 8] 5A and 5B are schematic diagrams showing a state in which a current collector is arranged on an end plate according to a second embodiment of the present invention, in which (A) is a plan view and (B) is a side view of the end plate as seen from the direction M. FIG. [Figure 9] 10A and 10B show a state in which a liquid seepage prevention member is provided on a current collector arranged on an end plate according to a second embodiment of the present invention, where (A) is a plan view and (B) is an enlarged view showing the area indicated by the dashed circle in the plan view of (A). [Figure 10] 10A shows a state in which a liquid seepage prevention member is provided on a current collector arranged on an end plate according to a second embodiment of the present invention, where (A) is a side view of the end plate as seen from the direction M, and (B) is a cross-sectional view showing the area indicated by the dashed circle in the plan view of (A) cut along line NN. DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] (First embodiment) [Overall structure] First, the overall configuration of a bipolar lead-acid battery according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing an outline of the structure of a bipolar lead-acid battery 100 according to an embodiment of the present invention.

[0018] As shown in FIG. 1, the bipolar lead-acid battery 100 in the first embodiment has a plurality of cell members 110, a plurality of bipolar plates (space forming members) 120, a first end plate (space forming member) 130, a second end plate (space forming member) 140, a lid 150, a positive electrode terminal component 160, and a negative electrode terminal component 170.

[0019] 1 shows a bipolar lead-acid battery 100 in which six cell elements 110 are stacked, but the number of cell elements 110 is determined by the battery design. The number of bipolar plates 120 is also determined by the number of cell elements 110.

[0020] Here, the stacking direction of the cell members 110 is defined as the Z direction (the left-right direction in FIG. 1), and the direction perpendicular to the Z direction, which is the up-down direction in the installed state, is defined as the X direction (the up-down direction in FIG. 1). The direction perpendicular to both the X direction and the Z direction is defined as the Y direction.

[0021] The lid 150 covers the upper end surface of the body of the bipolar lead-acid battery 100, which is formed in a substantially rectangular parallelepiped shape, and has recesses 151 and 152 on the upper surface that are line-symmetrical about the center in the X direction. A positive electrode terminal part 160 is disposed in the recess 151, and a negative electrode terminal part 170 is disposed in the recess 152.

[0022] A through hole 151b is formed in a bottom plate 151a of the recess 151. A through hole 152b is formed in a bottom plate 152a of the recess 152. The through hole 151b is formed above the first end plate 130, and the through hole 152b is formed above the second end plate 140.

[0023] The cell member 110 includes a positive electrode 111, a negative electrode 112, and a separator (electrolyte layer) 113. The positive electrode 111 includes positive electrode lead foils 111a and 111aa, which serve as a positive electrode current collector, and a positive electrode active material layer 111b. The negative electrode 112 includes negative electrode lead foils 112a and 112aa, which serve as a negative electrode current collector, and a negative electrode active material layer 112b.

[0024] The separator 113 is interposed between the positive electrode 111 and the negative electrode 112. The separator 113 is impregnated with an electrolyte. In the cell member 110, the positive electrode lead foils 111a, 111aa, the positive electrode active material layer 111b, the separator 113, the negative electrode active material layer 112b, and the negative electrode lead foils 112a, 112aa are stacked in this order.

[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 positive electrode lead foil 111aa constitutes the cell member 110 arranged at one end in the stacking direction and is provided on the first end plate 130. The negative electrode lead foil 112aa constitutes the cell member 110 arranged at the other end in the stacking direction and is provided on the second end plate 140.

[0027] 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 in a state where they are sandwiched between the substrates 121 of the bipolar plates 120.

[0028] 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.

[0029] That is, the bipolar plate 120 is a space-forming member that covers both the positive and negative sides of the cell member 110, includes a substrate 121 having a square planar shape, and a frame body 122 that surrounds the side surfaces of the cell member 110 and covers the four end faces of the substrate 121.

[0030] The bipolar plate 120 further includes pillars (not shown) that protrude perpendicularly from both sides of the substrate 121. The number of pillars protruding from each side of the substrate 121 may be one or more.

[0031] The substrate 121, frame 122, and column portions that make up the bipolar plate 120 are integrally formed from, for example, a thermoplastic resin. Examples of thermoplastic resins that form 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.

[0032] 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 pillars is the same as the dimension of the frame body 122. When multiple bipolar plates 120 are stacked with the frame bodies 122 and the pillars 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 pillars in contact with each other.

[0033] 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 separator 113 each have a through hole (not shown) formed therein for the column portion to pass through.

[0034] 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 of the substrate 121. The depth of the first recess 121b in the Z direction is deeper than the depth of the second recess 121c. The dimensions of the first recess 121b and the second recess 121c in the X direction and Y direction correspond to the dimensions of the positive electrode lead foil 111a and the negative electrode lead foil 112a in the X direction and Y direction.

[0035] The substrate 121 of the bipolar plate 120 is disposed between adjacent cell members 110 in the Z direction. Therefore, the substrate 121 of the bipolar plate 120 is a substrate that covers both the positive electrode 111 side of the cell member 110 and the negative electrode 112 side of the adjacent cell member 110.

[0036] A positive electrode lead foil 111a, which is a positive electrode current collector made of lead or a lead alloy, is disposed in a first recess 121b of the substrate 121 of the bipolar plate 120. A negative electrode lead foil 112a, which is a negative electrode current collector made of lead or a lead alloy, is disposed in a second recess 121c of the substrate 121 of the bipolar plate 120.

[0037] Specifically, the positive electrode lead foil 111a is bonded to the first recess 121b of the substrate 121 via an adhesive 114 provided between the first recess 121b of the substrate 121 and the positive electrode lead foil 111a. Also, the negative electrode lead foil 112a is bonded to the second recess 121c of the substrate 121 via an adhesive 114 provided between the second recess 121c of the substrate 121 and the negative electrode lead foil 112a.

[0038] A conductor 115 is disposed in the through-hole 121a of the substrate 121 of the bipolar plate 120. Both end surfaces of the conductor 115 are in contact with and joined to the positive electrode lead foil 111a and the negative electrode lead foil 112a. In other words, the positive electrode lead foil 111a and the negative electrode lead foil 112a are electrically connected by the conductor 115. As a result, all of the multiple cell members 110 are electrically connected in series.

[0039] Furthermore, frame 122 of substrate 121 has portions that surround each of the four side surfaces of cell member 110. Of these, portion 122a that surrounds the upper side surface (one side surface) in the X direction in Fig. 1 has a groove 128 formed on one end surface in the Z direction at a position different from the cross section shown in Fig. 1, which extends from the outer surface to the inner surface of surrounding portion 122a, as shown by the dashed line in Fig. 1.

[0040] 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 four side surfaces of the cell member 110. The first end plate 130 also includes one or more pillars (not shown) that protrude vertically from one surface of the substrate 131 (the surface facing the substrate 121 of the bipolar plate 120 that is arranged on the most positive electrode side).

[0041] The planar shape of substrate 131 is rectangular, and frame 132 is disposed on the outside of the four end faces of substrate 131. Furthermore, substrate 131, frame 132, and pillars are integrally formed from, for example, the above-mentioned thermoplastic resin. The number of pillars protruding from one surface of substrate 131 may be one or more, but the number will correspond to the number of pillars of bipolar plate 120 that come into contact with the pillars.

[0042] 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 pillar portions 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 pillar portions in contact with the frame body 122 and the pillar portions of the bipolar plate 120 arranged on the outermost side (positive electrode side).

[0043] This forms a space C between the substrate 121 of the bipolar plate 120 and the substrate 131 of the first end plate 130, and the Z-direction dimension of the space C is maintained by the column portions of the bipolar plate 120 and the first end plate 130, which are in contact with each other.

[0044] In this way, a column portion is provided on the first end plate 130. Therefore, through holes (not shown) that allow the column portion to penetrate are formed in the positive electrode lead foil 111aa, the positive electrode active material layer 111b, and the separator 113 of the cell member 110 arranged at one end in the stacking direction.

[0045] 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 111aa in the X and Y directions.

[0046] The positive electrode lead foil 111aa of the cell member 110 is arranged in the recess 131b of the substrate 131 of the first end plate 130 via an adhesive 114. 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 bipolar plate 120. The positive electrode lead foil 111aa has a positive electrode tab portion 11.

[0047] The frame 132 has portions surrounding each of the four side surfaces of the cell member 110. A tab insertion hole 133 extending in the X direction is formed in a portion 132a (portion covered by the lid) surrounding the upper side surface (one side surface) in the X direction in FIG.

[0048] Furthermore, a groove 138 extending from the outer surface to the inner surface of the enclosing portion 132a is formed on one end surface in the Z direction of the enclosing portion 132a at a position different from the cross section shown in Fig. 1, as indicated by the dashed line in Fig. 1. Furthermore, a tab placement recess 131d is formed on one surface of the substrate 131, continuing from the tab insertion hole 133 and reaching the recess 131b.

[0049] The portion of the positive electrode lead foil 111aa other than the positive electrode tab portion 11 is arranged in a recess 131b of the substrate 131 via an adhesive 114, and the base of the positive electrode tab portion 11 is arranged in a tab arrangement recess 131d of the substrate 131. An intermediate portion of the positive electrode tab portion 11 passes through a tab insertion hole 133 in the frame body 132 of the first end plate 130 and a through-hole 151b in the bottom plate 151a of the lid 150. The tip of the positive electrode tab portion 11 is bent at a substantially right angle within the recess 151 of the lid 150 and is connected to a positive electrode terminal part 160.

[0050] Furthermore, in the bipolar lead-acid battery 100 according to the embodiment of the present invention, a liquid seepage prevention member 180 is provided in the positive electrode tab portion 11 between the peripheral edge of the positive electrode lead foil 111aa and the frame body 132 (enclosing portion 132a) of the first end plate 130. The liquid seepage prevention member 180 will be described later.

[0051] 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 four side surfaces of the cell member 110. The second end plate 140 also includes one or more pillars (not shown) that protrude 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).

[0052] The planar shape of substrate 141 is rectangular, and frame 142 is disposed on the outside of the four end faces of substrate 141. Furthermore, substrate 141, frame 142, and pillars are integrally formed from, for example, the above-mentioned thermoplastic resin. The number of pillars protruding from one surface of substrate 141 may be one or more, but the number will correspond to the number of pillars of bipolar plate 120 that come into contact with the pillars.

[0053] 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 column portions 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 column portions in contact with the frame body 122 and the column portions of the bipolar plate 120 arranged on the outermost side (negative electrode side).

[0054] This forms a space C between the substrate 121 of the bipolar plate 120 and the substrate 141 of the second end plate 140, and the Z-direction dimension of the space C is maintained by the pillar portions of the bipolar plate 120 and the pillar portions of the second end plate 140, which are in contact with each other.

[0055] In this way, a column portion is provided on the second end plate 140. Therefore, through holes (not shown) that allow the column portion to pass through are formed in the negative electrode lead foil 112aa, the negative electrode active material layer 112b, and the separator 113 of the cell member 110 arranged on the other end side in the stacking direction, i.e., the outermost side (negative electrode side).

[0056] 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 112aa in the X and Y directions.

[0057] The negative electrode lead foil 112aa of the cell member 110 is arranged in the recess 141b of the substrate 141 of the second end plate 140 via an adhesive 114. The dimension in the X direction 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 dimension in the X direction of the negative electrode lead foil 112a arranged on the other surface of the substrate 121 of the bipolar plate 120. The negative electrode lead foil 112aa has a negative electrode tab portion 12.

[0058] The frame 142 has portions surrounding each of the four side surfaces of the cell member 110. A through hole 143 extending in the X direction is formed in a portion 142a (portion covered by the lid) surrounding the upper side surface (one side surface) in the X direction in FIG.

[0059] Furthermore, a groove 148 extending from the outer surface to the inner surface of the enclosing portion 142a is formed on one end surface in the Z direction of the enclosing portion 142a at a position different from the cross section shown in Fig. 1, as shown by the dashed line in Fig. 1. Furthermore, a tab placement recess 141c continuing from the through hole 143 and reaching the recess 141b is formed on one surface of the substrate 141.

[0060] The portion of the negative electrode lead foil 112aa other than the negative electrode tab portion 12 is arranged in a recess 141b of the substrate 141 via an adhesive 114, and the base of the negative electrode tab portion 12 is arranged in a tab arrangement recess 141c of the substrate 141. The middle portion of the negative electrode tab portion 12 passes through a through-hole 143 in the frame body 142 of the second end plate 140 and a through-hole 152b in the bottom plate 152a of the lid 150. The tip portion of the negative electrode tab portion 12 is bent at a substantially right angle within the recess 152 of the lid 150 and connected to a negative electrode terminal part 170.

[0061] Furthermore, in the bipolar lead-acid battery 100 according to the embodiment of the present invention, a liquid seepage prevention member 180 is provided in the negative electrode tab portion 12 between the peripheral edge of the negative electrode lead foil 112aa and the frame body 142 (enclosing portion 142a) of the second end plate 140. The liquid seepage prevention member 180 will be described later.

[0062] Here, when joining adjacent bipolar plates 120 together, a first end plate 130 and an adjacent bipolar plate 120, or a second end plate 140 and an adjacent bipolar plate 120, various welding methods can be used, such as 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.

[0063] The objects to be welded include not only the frames arranged at opposing positions in the adjacent bipolar plate 120, first end plate 130, and second end plate 140, but also the respective pillars.

[0064] As can be seen from the above description, the bipolar plate 120 is a space-forming member that includes a substrate 121 that covers both the positive electrode side and the negative electrode side of the cell member 110, and a frame 122 that surrounds all side surfaces 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 all side surfaces of the cell member 110.

[0065] The second end plate 140 is a space-forming member that includes a substrate 141 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 all side surfaces of the cell member 110. In other words, the substrates 121, 131, and 141 are substrates that cover at least one of the positive electrode side and the negative electrode side of the cell member 110, and the substrate 121 is a substrate that covers both the positive electrode side and the negative electrode side of the cell member 110.

[0066] 1, grooves 128 in the surrounding portions 122a of adjacent bipolar plates 120 form injection holes 18 extending from the outer surfaces to the inner surfaces of the surrounding portions 122a. Grooves 138, 148 in the surrounding portions 132a, 142a of the first end plate 130 and the second end plate 140, together with grooves 128 in the surrounding portions 122a of the adjacent bipolar plates 120, form injection holes 18 extending from the outer surfaces to the inner surfaces of the surrounding portions 132a, 142a.

[0067] Each of the liquid filling holes 18 thus formed is continuous with each of the liquid filling ports provided in the lid 150. Then, the electrolyte is poured into each space C from each of the liquid filling ports through each of the liquid filling holes 18, whereby the separator 113 is impregnated with the electrolyte.

[0068] Next, the liquid seepage prevention member 180 according to the first embodiment of the present invention will be described with reference to Figures 2 to 4. The liquid seepage prevention member 180 may be provided on both the positive electrode side and the negative electrode side, but must be provided at least on the positive electrode side. The liquid seepage prevention members 180 provided on the positive electrode side and the negative electrode side have the same configuration. Therefore, the following description will be given taking the liquid seepage prevention member 180 provided on the positive electrode side as an example.

[0069] 2A and 2B are schematic diagrams of a first end plate 130 according to a first embodiment of the present invention, with (A) being a plan view and (B) being a side view of the first end plate 130 as viewed from the direction M. Note that the shape of the first end plate 130 shown in each of the figures from FIG. 2 onwards is drawn as an example of a square. Furthermore, hatching has been omitted from the first end plate 130 shown in each of the figures from FIG. 2 onwards.

[0070] In the plan view of Fig. 2(A), a frame-shaped frame body 132 of the first end plate 130 is shown at the outermost side. A substrate 131 is disposed inside the frame body 132 and in contact with the frame body 132. The boundary between the substrate 131 and the frame body 132 in the Z direction is indicated by a dashed line in Fig. 2(B).

[0071] Furthermore, a recess 131b for arranging the positive electrode lead foil 111aa is formed in the substrate 131. As is clear from Fig. 1, the recess 131b is formed in a recessed shape that is deeper in the Z direction from the surface that is continuous with the frame body 132 of the substrate 131, in accordance with the thickness of the positive electrode lead foil 111aa to be arranged. Therefore, the line shown as a square at the innermost side in the plan view of Fig. 2(A) is the line that separates the recess 131b from the substrate 131.

[0072] 2 and other plan views of first end plate 130, for example, the distance in the Y direction of frame 132 is depicted as being equal to the distance from the position where substrate 131 contacts frame 132 to the position that separates substrate 131 from recess 131b. However, the shape of first end plate 130 does not necessarily have to be this shape.

[0073] For example, in the first end plate 130, on the side where the tab insertion hole 133 described later is formed, the distance in the Y direction of the frame body 132 may be shorter than the distance from the position where the substrate 131 contacts the frame body 132 to the position that separates the substrate 131 from the recess 131b. On the other hand, on the other hand, on the remaining three sides, the latter may be shorter than the former.

[0074] As described above, the tab insertion hole 133 extending in the X direction is formed in the surrounding portion 132a of the frame body 132. Since Fig. 2(A) is a plan view, the tab insertion hole 133 cannot be seen directly, but is indicated by a dashed line. In contrast, in Fig. 2(B), the tab insertion hole 133 is visible.

[0075] Furthermore, on the surface of the substrate 131 on which the positive electrode lead foil 111aa is arranged, a tab arrangement recess 131d is formed that continues from the tab insertion hole 133 and reaches the recess 131b. The positive electrode lead foil 111aa arranged in the recess 131b is rectangular, and one of its four sides has an ear 11 (hereinafter, the ear will be referred to as a "tab") formed on it so as to protrude outward from the periphery of the positive electrode lead foil 111aa for connection to the positive electrode terminal component 160. The tab arrangement recess 131d is formed for arranging the positive electrode tab 11.

[0076] The tab placement recess 131d described below is formed on the left side in the Y direction, for example, as shown in Fig. 2(A). This is to match the shape of the positive electrode tab portion 11 that is arranged as described above. Therefore, the position where the tab placement recess 131d is arranged in the Y direction is determined by the position where the positive electrode tab portion 11 is formed.

[0077] 3A and 3B are schematic diagrams showing a state in which a current collector (positive electrode lead foil) 111aa is arranged on a first end plate 130 according to the first embodiment of the present invention, where (A) is a plan view and (B) is a side view of the first end plate 130 as viewed from the direction M. Note that with respect to the protrusion of the positive electrode tab portion 11 in the X direction, the middle portion and the tip portion connected to the positive electrode terminal part 160 are not depicted in FIG. 3 and FIG. 4, which will be described later.

[0078] As described above, the positive electrode lead foil 111aa is attached to the recess 131b of the first end plate 130 via the adhesive 114. At this time, the positive electrode tab portion 11 is passed through the tab insertion hole 133 in advance, placed in the tab placement recess 131d, and then placed in the recess 131b.

[0079] Therefore, when the positive electrode lead foil 111aa is placed in the recess 131b, the middle and tip of the positive electrode tab portion 11 protrude outward from the frame body 132. In FIG. 3(B), they protrude toward the front side of the paper.

[0080] In this state, the positive electrode lead foil 111aa is provided with a liquid seepage prevention member 180. Fig. 4 shows a state in which the liquid seepage prevention member 180 is provided on the current collector (positive electrode lead foil) 111aa arranged on the first end plate 130 according to the first embodiment of the present invention, where (A) is a plan view and (B) is an enlarged view showing the area indicated by the dashed circle in the plan view of (A).

[0081] The reason why the liquid seepage prevention member 180 is provided in the first place is that, as described above, during the manufacturing process of the bipolar lead-acid battery 100, corrosion may occur in the tab portion of the positive electrode lead foil 111aa, which is an area disposed inside the bipolar lead-acid battery 100, when, for example, chemical formation is performed after injection of the electrolyte. If the electrolyte seeps up from the peripheral edge of the positive electrode lead foil 111aa toward the positive electrode tab portion 11 and corrosion of the positive electrode tab portion 11 progresses, the electrolyte may eventually seep up to the positive electrode terminal part 160. Therefore, it is necessary to prevent the corrosion of the positive electrode tab portion 11 from progressing.

[0082] When the positive electrode lead foil 111aa is placed in the recess 131c, the positive electrode tab portion 11 is placed in the tab placement recess 131d and protrudes to the outside of the frame body 132 through the tab insertion hole 133. At this time, at least the surface of the positive electrode tab portion 11 that comes into contact with the tab placement recess 131d (for convenience, this surface is referred to as the "lower surface") is fixed to the tab placement recess 131d by the adhesive 114.

[0083] However, the adhesive 114 is provided only in the recess 131b and the tab arrangement recess 131d, and the adhesive 114 is not applied to the inside of the tab insertion hole 133. Therefore, although the positive electrode tab portion 11 has its lower surface and two surfaces that contact the lower surface and rise in the Z direction and are in contact with the tab insertion hole 133 inside the tab insertion hole 133, they are not fixed by the adhesive 114.

[0084] Inside the tab insertion hole 133, there is a small gap between the surface opposite the lower surface of the positive electrode tab portion 11 (for convenience, this surface will be referred to as the "upper surface") and the surface of the tab insertion hole 133 facing the upper surface of the positive electrode tab portion 11.

[0085] Therefore, in the first embodiment, a first liquid seepage prevention member 180a is provided in the positive electrode tab portion 11 between the peripheral edge of the positive electrode lead foil 111aa and the outside of the frame body 132, in contact with the positive electrode tab portion 11 and along the frame body 132. By arranging the first liquid seepage prevention member 180a in such a position, it is possible to prevent the electrolyte from seeping up from the peripheral edge of the positive electrode lead foil 111aa through the positive electrode tab portion 11 to the positive electrode terminal part 160 arranged on the outside of the frame body 132, at the entrance, so to speak.

[0086] In this way, the first liquid seepage prevention member 180a may simply be placed along the frame body 132 in contact with the positive electrode tab portion 11. However, it is also possible to make the first liquid seepage prevention member 180a penetrate into the gap between the upper surface of the positive electrode tab portion 11 and the surface of the tab insertion hole 133 that faces the upper surface of the positive electrode tab portion 11.

[0087] As described above, by disposing the first liquid seepage prevention member 180a, it is possible to reduce the seepage of the electrolyte solution through the positive electrode tab portion 11. However, to ensure the reduction in seepage, it is also possible to further provide a second liquid seepage prevention member 180b as shown in FIG.

[0088] That is, after the positive electrode lead foil 111aa is placed in the recess 131b, the above-described first liquid seepage prevention member 180a can be provided directly on the positive electrode tab portion 11. On the other hand, it is difficult to take measures to prevent electrolyte seepage onto the lower surface of the positive electrode tab portion 11 that has already been placed in the tab placement recess 131d via the adhesive 114 and onto the two surfaces that contact the lower surface and rise in the Z direction.

[0089] 4, the second liquid seepage prevention member 180b is provided along the peripheral edge of the positive electrode lead foil 111aa and is also provided in the X direction from the peripheral edge of the positive electrode lead foil 111aa toward the frame 132 along the positive electrode tab portion 11. As a result, the second liquid seepage prevention member 180b is formed in a substantially L-shape. In addition, the portion of the second liquid seepage prevention member 180b that contacts the frame 132 is also arranged to contact the first liquid seepage prevention member 180a.

[0090] The second liquid seepage prevention member 180b is formed in this shape and is further arranged to contact one end and the other end of the first liquid seepage prevention member 180a arranged along the frame body 132 and sandwich the first liquid seepage prevention member 180a (positive electrode tab portion 11), thereby preventing the electrolyte from seeping in from the underside of the positive electrode tab portion 11 and the two surfaces that contact the underside and rise in the Z direction. As a result, it is possible to more reliably suppress seepage of the electrolyte through the positive electrode tab portion 11 to the positive electrode terminal part 160 and corrosion in the area of ​​the positive electrode tab portion 11.

[0091] As shown in Figure 4, the liquid seepage prevention member 180 in the first embodiment of the present invention is divided into a first liquid seepage prevention member 180a and a second liquid seepage prevention member 180b, but these may also be formed and arranged integrally.

[0092] [Manufacturing method] The bipolar lead-acid battery 100 of the first embodiment can be manufactured, for example, by a method including the steps described below. When manufacturing the bipolar lead-acid battery 100, the battery body is assembled in a state in which both the positive electrode tab portion 11 and the negative electrode tab portion 12, or at least the tip of the positive electrode tab portion 11, extend upward in the X direction.

[0093] <Manufacturing process of bipolar plates with lead foil for positive and negative electrodes> First, the substrate 121 of the bipolar plate 120 is placed on a workbench with the first recess 121b facing upward. Adhesive 114 is applied to the first recess 121b, and the positive electrode lead foil 111a is placed in the first recess 121b. At this time, the column portion of the bipolar plate 120 is passed through the through-hole of the positive electrode lead foil 111a. The adhesive 114 is cured, and the positive electrode lead foil 111a is attached to one surface of the substrate 121.

[0094] Next, the substrate 121 is placed on a workbench with the second recess 121c facing upward, and the conductor 115 is inserted into the through-hole 121a. Then, adhesive 114 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 of the bipolar plate 120 is passed through the through-hole of the negative electrode lead foil 112a. The adhesive 114 is cured, and the negative electrode lead foil 112a is attached to the other surface of the substrate 121.

[0095] Then, for example, the above-mentioned resistance welding method is used to join the conductor 115 to the positive electrode lead foil 111a and the negative electrode lead foil 112a. This results in a 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.

[0096] <Production process of end plates with lead foil for positive electrodes> The substrate 131 of the first end plate 130 is placed on a workbench with the recess 131b facing upward, and adhesive 114 is applied to the recess 131b. The positive electrode tab portion 11 is then inserted tip-first into the tab insertion hole 133, and the positive electrode lead foil 111aa is placed in the recess 131b. At this time, the column portion of the end plate 130 is passed through the through-hole in the positive electrode lead foil 111a. The adhesive 114 is cured, and the positive electrode lead foil 111aa is attached to one surface of the substrate 131. This results in the first end plate 130 with the positive electrode lead foil 111aa attached to one surface of the substrate 131.

[0097] More specifically, first, the tip of the positive electrode tab portion 11 of the positive electrode lead foil 111aa is passed through the tab insertion hole 133 of the frame 132 of the first end plate 130 and protrudes to the outside. Meanwhile, the base of the positive electrode tab portion 11, continuing from the peripheral edge of the positive electrode lead foil 111aa, is placed in the tab placement recess 131d of the substrate 131. Furthermore, the portion other than the positive electrode tab portion 11 is placed in the recess 131b of the substrate 131. Then, the positive electrode tab portion 11 is fixed with adhesive 114.

[0098] <Manufacturing process of 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 upward, and adhesive 114 is applied to the recess 141b. Then, the negative electrode tab portions 1 and 2 are inserted tip-first into the tab insertion holes 133, and the negative electrode lead foil 112aa is placed in the recess 141b. At this time, the column portions of the second end plate 140 are passed through the through holes in the negative electrode lead foil 112aa. The adhesive 114 is cured to obtain the second end plate 140, with the negative electrode lead foil 112aa attached to one surface of the substrate 141.

[0099] More specifically, the tip of the negative electrode tab portion 12 of the negative electrode lead foil 112aa is passed through a through-hole 143 in the frame 142 of the second end plate 140 and protrudes to the outside. Meanwhile, the base of the negative electrode tab portion 12, continuing from the peripheral edge of the negative electrode lead foil 112aa, is placed in the tab placement recess 141c of the substrate 141. The portion other than the negative electrode tab portion 12 is placed in the recess 141b of the substrate 141. They are then fixed in place with an adhesive. This completes the production of the end plate with positive electrode lead foil and the end plate with negative electrode lead foil.

[0100] <The process of stacking and joining plates> First, the first end plate 130 to which the positive electrode lead foil 111aa is fixed is placed on a workbench with the positive electrode lead foil 111aa facing up, and the positive electrode active material layer 111b is placed on top of the positive electrode lead foil 111aa. At this time, the column portions of the first end plate 130 are passed through the through holes 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.

[0101] 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 of the bipolar plate 120 are passed through the through holes of the separator 113 and the negative electrode active material layer 112b, and placed on the column parts of the first end plate 130. Furthermore, the frame 122 of the bipolar plate 120 is placed on the frame 132 of the first end plate 130.

[0102] In this state, first end plate 130 is fixed, and vibration welding is performed while vibrating bipolar plate 120 in the diagonal direction of substrate 121. As a result, frame 122 of bipolar plate 120 is joined onto frame 132 of first end plate 130, and the pillar portions of bipolar plate 120 are joined onto the pillar portions of first end plate 130.

[0103] As a result, the bipolar plate 120 is joined onto the first end plate 130. Then, the cell member 110 is placed in the space C formed by the first end plate 130 and the bipolar plate 120, and the positive electrode lead foil 111a is exposed on the upper surface of the bipolar plate 120.

[0104] 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.

[0105] 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.

[0106] Finally, the positive electrode active material layer 111b, the separator 113, and the negative electrode active material layer 112b are placed in this order on the uppermost bipolar plate 120 of the assembly in which all the bipolar plates 120 are joined together. Then, the second end plate 140 is placed with the negative electrode lead foil 112aa side facing downward.

[0107] 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.

[0108] The above has described the flow of placing the positive electrode active material layer 111b, the negative electrode active material layer 112b, and the separator 113 on the bipolar plate 120, and stacking and bonding the plates together.

[0109] Next, the lid 150 is placed above the battery body in the X direction. The tips of the positive electrode tab portion 11 and the negative electrode tab portion 12 are passed through the through holes 151b, 152b of the lid 150, and the lid 150 is placed on the upper surface of the battery body in the Z direction and heat-welded.

[0110] The positive electrode terminal component 160 and the negative electrode terminal component 170 are then placed in the recesses 151 and 152 of the lid 150, respectively, and fixed to the upper surfaces of the bottom plates 151a and 152a with an adhesive. Next, the tip portions of the positive electrode tab portion 11 and the negative electrode tab portion 12 are bent at predetermined positions and connected to the relay portions of the positive electrode terminal component 160 and the negative electrode terminal component 170, respectively.

[0111] <Injection and chemical conversion process> In the stacking and joining process of the plates described above, a joint structure is formed by vibration welding the opposing surfaces of the frame bodies, and filling holes 18 are formed at the positions of the spaces C on, for example, one end surface in the X direction of the bipolar lead-acid battery 100 by vibration welding the edges of the grooves 128, 138, and 148 of the opposing frame bodies. Then, a predetermined amount of electrolyte is poured into each space C through the filling holes 18 in the battery body from the filling holes in the lid 150, thereby impregnating the separator 113 with the electrolyte. Then, the filling holes in the lid 150 are sealed. Then, chemical formation is performed under predetermined conditions, thereby completing the bipolar lead-acid battery 100.

[0112] As described above, in the bipolar lead-acid battery 100 according to the first embodiment of the present invention, the liquid seepage prevention member 180 is provided in the positive electrode tab portion 11 between the peripheral edge of the positive electrode lead foil 111aa and the frame 132. By adopting such a configuration, corrosion can be suppressed in the region of the tab portion of the current collector that is provided on the end plate and connected to the terminal, and that is disposed inside the battery. Therefore, it is possible to provide a bipolar storage battery and a method for manufacturing a bipolar storage battery that are less susceptible to deterioration in battery performance and have a longer lifespan.

[0113] The above description has been given taking as an example the liquid seepage prevention member 180 as shown in Fig. 4. However, the liquid seepage prevention member 180 is not limited to this type, and the following two embodiments can also be adopted as modified examples.

[0114] First, explanation will be made with reference to Fig. 5. Fig. 5 shows a state in which another form of liquid seepage prevention member 181 is provided on a current collector (positive electrode lead foil 111aa) arranged on a first end plate 130 according to the first embodiment of the present invention, where (A) is a plan view and (B) is an enlarged view showing an area indicated by a dashed circle in the plan view of (A).

[0115] In the embodiment shown in Figure 5 (hereinafter referred to as the "first variant"), in the positive electrode tab portion 11 which is provided continuously with the peripheral edge portion of the positive electrode lead foil 111aa, a liquid seepage prevention member 181 is provided from the peripheral edge portion of the positive electrode lead foil 111aa to the frame body 132 (inside the frame body 132).

[0116] The liquid seepage prevention member 181 is formed of a resin such as epoxy resin, and covers an area from the peripheral edge of the positive electrode lead foil 111aa in the positive electrode tab portion 11 to the inside of the frame body 132. Note that, although Fig. 5 shows a case where the liquid seepage prevention member 181 is formed so that its width in the Y direction is substantially the same as the width of the positive electrode tab portion 11 in the Y direction, the liquid seepage prevention member 181 may be formed so that its width in the Y direction is wider than the width of the positive electrode tab portion 11 in the Y direction.

[0117] However, when forming the Y-direction width of the liquid seepage prevention member 181 to be wider than the Y-direction width of the positive electrode tab portion 11, there is naturally an upper limit to this width in relation to other structures in the bipolar lead-acid battery 100.

[0118] Next, we will look at an embodiment (hereinafter referred to as "second modified example") shown in Fig. 6. Fig. 6 shows a state in which a liquid seepage prevention member 182 of yet another embodiment is provided on a current collector (positive electrode lead foil 111aa) arranged on a first end plate 130 according to the first embodiment of the present invention, where (A) is a plan view and (B) is an enlarged view showing an area indicated by a dashed circle in the plan view of (A).

[0119] The liquid seepage prevention member 182 in the second modified example is formed of, for example, ABS resin. The liquid seepage prevention member 182 of the second modified example can be provided in addition to the liquid seepage prevention member 181 described as the first modified example.

[0120] That is, if the resin constituting the liquid seepage prevention member 181 in the first modified example functions as an adhesive, for example, the liquid seepage prevention member 182 can be provided by overlapping this adhesive. With such a configuration, it is possible to more reliably cover the area from the peripheral edge of the positive electrode lead foil 111aa in the positive electrode tab portion 11 to the inside of the frame body 132. This makes it possible to prevent corrosion in the positive electrode tab portion 11 and more reliably prevent the electrolyte from seeping up to the positive electrode terminal part 160.

[0121] The area of ​​the positive electrode tab portion 11 that is covered by the liquid seepage prevention member 181 or the liquid seepage prevention member 182 may be roughly polished in advance. By polishing this area, the adhesion of the liquid seepage prevention member 181 made of resin becomes stronger.

[0122] The polished area is at least the area covered by the liquid seepage prevention member 181. Therefore, the area disposed inside the tab insertion hole 133 in the positive electrode tab portion 11, the intermediate portion, or the area extending to the tip portion may be polished.

[0123] (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.

[0124] In the first embodiment, the end plates are configured such that the positive electrode tab portion 11 of the positive electrode lead foil 111aa passes through a tab insertion hole 133 formed in the frame 132 and is disposed outside the frame 132. In contrast, the end plates of the bipolar lead-acid battery 100A in the second embodiment are configured without the tab insertion hole 133. This point will be described with reference to FIG. 7.

[0125] As in the first embodiment, the following description will be given taking the first end plate on the positive electrode side as an example, but it is of course possible to provide a liquid seepage prevention member by adopting a similar structure on the second end plate on the negative electrode side.

[0126] 7A and 7B are schematic diagrams of a first end plate 130A according to a second embodiment of the present invention, in which (A) is a plan view and (B) is a side view of the first end plate 130A as seen from the direction M.

[0127] 7(A), the first end plate 130A has a frame 132A and a substrate 131A arranged from the outside to the inside, which is the same as the first end plate 130 in the first embodiment. Also, a tab arrangement recess 131Ac for arranging the positive electrode tab portion 11 is formed in the recess 131Ab of the substrate 131A when the positive electrode lead foil 111aa is arranged.

[0128] On the other hand, in the first end plate 130A of the second embodiment, the frame body 132A is cut out to form a frame body cutout portion 132Ab so as to be continuous with the tab arrangement recess 131Ac. That is, as shown in Fig. 7(B) , the frame body cutout portion 132Ab is cut out from the surface 132Ac of the frame body 132A facing the frame body 122 of the adjacent bipolar plate 120 to the same height in the Z direction as the position of the tab arrangement recess 131Ac.

[0129] In this way, a frame cutout 132Ab is formed in the frame 132. Therefore, when the positive electrode lead foil 111aa is placed in the recess 131Ab, the positive electrode tab portion 11 is placed without any step in the frame cutout 132Ab that continues from the tab placement recess 131Ac. This state is shown in Figure 8.

[0130] FIG. 8 is a schematic diagram showing a state in which a current collector (positive electrode lead foil 111aa) is arranged on a first end plate 130A according to a second embodiment of the present invention, where (A) is a plan view and (B) is a side view of the first end plate 130A as viewed from the direction M.

[0131] 7(B) or 8(B) described above, the frame cutout 132Ab is cut downward in the Z direction from the surface 132Ac of the frame 132A facing the frame 122 of the adjacent bipolar plate 120 so as to be continuous with the tab placement recess 131Ac. The lowermost surface 132Ad of the frame cutout 132Ab is flush with the tab placement recess 131Ac. Therefore, the positive electrode tab portion 11 is also arranged on the first end plate 130A without being bent midway.

[0132] A liquid seepage prevention member 183 is disposed on the thus arranged positive electrode tab portion 11. Next, a state in which the liquid seepage prevention member 183 is disposed on the first end plate 130A will be described with reference to Figures 9 and 10.

[0133] 9 shows a state in which a liquid seepage prevention member 183 is provided on a current collector (positive electrode lead foil 111aa) arranged on a first end plate 130A according to a second embodiment of the present invention. FIG. 9(A) is a plan view, and FIG. 9(B) is an enlarged view showing an area indicated by a dashed circle in the plan view of FIG. 9(A). As shown in FIGS. 9(A) and 9(B), in the positive electrode tab portion 11, the liquid seepage prevention member 183 is provided between the peripheral edge of the positive electrode lead foil 111aa and the outside of the frame body 132A.

[0134] 9(A) and 9(B) are both plan views, it is unclear how the positional relationship between the recess 131Ab and the frame 132A in the liquid seepage prevention member 183 is. This point will be explained with reference to FIG.

[0135] 10 shows a state in which a liquid seepage prevention member 183 is provided on a current collector (positive electrode lead foil 111aa) arranged on a first end plate 130A according to a second embodiment of the present invention. Fig. 10(A) is a side view of the first end plate 130A as viewed from the direction M, and Fig. 10(B) is a cross-sectional view showing the region indicated by the dashed circle in the plan view of Fig. 10(A) taken along line NN.

[0136] 10(A), the first surface 183a of the liquid seepage prevention member 183 is formed so as to be flush with the surface 132Ac of the frame 132A that faces the frame 122 of the adjacent bipolar plate 120. In addition, as shown in FIG. 9(B), the length of the first surface 183a in the X direction is also formed to be the same as the length of the frame 132 in the X direction.

[0137] This is to prevent a step from occurring between the surface 132Ac of the frame body 132A and the surface of the frame body 122, which are opposing surfaces, when the bipolar plate 120 is placed on the first end plate 130A and vibration welding is performed.

[0138] 10(B), in a cross-sectional view of the liquid seepage prevention member 183, the second surface 183b is formed one step lower in the Z direction from the first surface 183a. Therefore, the cross-sectional shape of the liquid seepage prevention member 183 is approximately L-shaped.

[0139] The liquid seepage prevention member 183 formed in this shape is bonded to the upper surface of the positive electrode tab portion 11 to which the adhesive 114 is applied. At this time, the liquid seepage prevention member 183 is positioned so that the first surface 183a does not protrude in the X direction and Z direction from the surface 132Ac of the frame 132A that faces the frame 122 of the adjacent bipolar plate 120.

[0140] As described above, when the liquid seepage prevention member 183 is arranged, the upper surface of the positive electrode tab portion 11 may be polished.

[0141] By adopting the above-described configuration, it is possible to suppress corrosion in the area of ​​the tab portion of the current collector that is provided on the end plate and connected to the terminal and that is disposed inside the storage battery, thereby providing a bipolar storage battery and a method for manufacturing the same that are less susceptible to deterioration in battery performance and have a longer lifespan.

[0142] In particular, since the frame cutout 132Ab is formed, when placing the positive electrode lead foil 111aa in the recess 131b, it is not necessary to pass the positive electrode tab portion 11 through the tab insertion hole 133 as in the liquid seepage prevention member 180 in the first embodiment. Therefore, the placement of the positive electrode lead foil 111aa in the recess 131b is completed at the same time. This can simplify the manufacturing process of the bipolar lead-acid battery 100A and also contributes to the alignment of the positive electrode lead foil 111aa.

[0143] In the above description, no particular reference has been made to the region of the tab portion where the liquid seepage prevention member is provided. For example, in the current collector arranged on the end plate shown in Figure 4, the liquid seepage prevention member is provided in a portion of the area from the peripheral edge of the current collector to the outside of the frame. However, this is not limited to the case where the liquid seepage prevention member is provided in a portion of the area from the peripheral edge of the current collector to the outside of the frame. For example, as shown in Figures 5 and 6, the liquid seepage prevention member may be provided in the entire area from the peripheral edge of the current collector to the outside of the frame. Therefore, it is sufficient that the liquid seepage prevention member is provided in at least a portion of the area from the peripheral edge of the current collector to the outside of the frame.

[0144] The techniques described in the embodiments of the present invention may also be configured as follows. (1) a positive electrode active material layer; a negative electrode active material layer; a current collector in contact with either the positive electrode active material layer or the negative electrode active material layer, or both; a separator disposed between the positive electrode active material layer and the negative electrode active material layer facing each other; a pair of end plates sandwiching the positive electrode active material layer and the current collector, or the negative electrode active material layer and the current collector, and the separator in a stacked state; the end plate includes a substrate including one of the positive electrode active material layer and the current collector, or the negative electrode active material layer and the current collector, and a frame surrounding side surfaces of the positive electrode active material layer and the current collector, or the negative electrode active material layer and the current collector, the current collector provided on the substrate includes a tab portion that protrudes from the inside of the frame body on which the current collector is disposed toward the outside of the frame body and is electrically connected to a terminal that extracts electricity to the outside, A bipolar storage battery, characterized in that a liquid seepage prevention member is provided in at least a portion of the tab portion between the peripheral edge of the current collector and the outside of the frame body. (2) The bipolar storage battery according to (1) above, wherein the liquid permeation prevention member is a first liquid permeation prevention member provided along the frame body in contact with the tab portion. (3) The bipolar storage battery described in (2) above, characterized in that the liquid seepage prevention member further includes a second liquid seepage prevention member, and the second liquid seepage prevention member is provided from both ends of the first liquid seepage prevention member toward the current collector and is provided continuously along the peripheral portion of the current collector. (4) The bipolar lead-acid battery according to (1), wherein the liquid seepage prevention member is a resin that covers an area of ​​the tab portion from the peripheral edge of the current collector to the inside of the frame. (5) The bipolar storage battery according to any one of (1) to (4) above, wherein the tab portion is inserted into a tab insertion hole formed in the frame. (6) The bipolar storage battery according to (1) above, wherein the frame has a frame cutout in which the tab portion is disposed. (7) The bipolar storage battery according to (6) above, wherein the liquid seepage prevention member is a resin that covers the area from the peripheral edge of the current collector in the tab portion to the frame cutout portion. (8) The bipolar storage battery according to (7) above, characterized in that in the liquid seepage prevention member, the resin placed in the frame cutout portion has the same height as the frame. (9) A bipolar storage battery according to any one of (1) to (8) above, characterized in that the current collector is made of lead or a lead alloy. (10) preparing a pair of end plates by arranging the current collector on a substrate of the end plate by inserting a tab portion formed on the current collector into a tab insertion hole formed on the substrate; providing a liquid seepage prevention member in at least a portion of one or both of the pair of end plates between a peripheral edge of the current collector in the tab portion and an outer side of a frame of the end plate; a step of disposing a first active material layer so as to contact the current collector disposed on one of the end plates on which the liquid seepage prevention member is provided; disposing a separator in contact with the first active material layer; disposing a second active material layer in contact with the separator; disposing the current collector so as to be in contact with the second active material layer; repeating the step of stacking the first active material layer, the separator, the second active material layer, and the current collector until a desired performance is obtained; a step of placing the other end plate obtained in the manufacturing step; A method for manufacturing a bipolar storage battery, comprising: Liquid soak-up prevention materialLiquid soak-up prevention material

[0145] As described above, the embodiments of the present invention have been described using a bipolar lead-acid battery as an example. However, if the above description is applicable to other batteries that use metals other than lead for the current collectors, this does not mean that the application of the above description is excluded. [Explanation of symbols]

[0146] 11 Positive electrode tab 12 Negative electrode tab 18. Filling hole 100, 100A... Bipolar lead-acid battery 110 Cell member 111...Positive electrode 111a...Lead foil for positive electrode 111aa···Positive electrode lead foil (positive electrode current collector plate that constitutes one cell component) 111b...Active material layer for positive electrode 112...Negative electrode 112a...Lead foil for negative electrode 112aa Lead foil for negative electrode (negative electrode current collector plate constituting one cell component) 112b...Active material layer for negative electrode 113 Separator 114... Adhesive 115 Conductor 120···Bipolar Plate 121....Bipolar plate substrate 121a: Through hole in substrate 122....Bipolar plate frame 122a: A portion surrounding one side of the cell member 128... Groove forming injection hole 130 First end plate 131: First end plate substrate (substrate covering one of the positive and negative sides of the cell member) 132 First end plate frame 132a: A portion surrounding one side of the cell member 138....Groove forming injection hole 133 Tab insertion hole 140...Second end plate 141: Second end plate substrate (substrate covering one of the positive and negative sides of the cell member) 142... Second end plate frame 142a: A portion surrounding one side of the cell member 143 Tab insertion hole 148....Groove forming injection hole 150...lid 151···Covered portion of lid 152···Covered portion of lid 160 Positive terminal parts 170 Negative terminal part 180....Liquid seepage prevention material 180a: First liquid seepage prevention member 180b... Second liquid seepage prevention member C: Space for accommodating cell components

Claims

1. a positive electrode active material layer; a negative electrode active material layer; a current collector in contact with either the positive electrode active material layer or the negative electrode active material layer, or both; a separator disposed between the positive electrode active material layer and the negative electrode active material layer facing each other; a pair of end plates sandwiching the positive electrode active material layer and the current collector, or the negative electrode active material layer and the current collector, and the separator in a stacked state; the end plate includes a substrate covering one of the positive electrode active material layer and the current collector or the negative electrode active material layer and the current collector, and a frame surrounding side surfaces of the positive electrode active material layer and the current collector or the negative electrode active material layer and the current collector, the current collector provided on the substrate includes a tab portion that protrudes from the inside of the frame body on which the current collector is disposed toward the outside of the frame body and is electrically connected to a terminal that extracts electricity to the outside, A bipolar storage battery, characterized in that a liquid seepage prevention member is provided in at least a portion of the tab portion between the peripheral edge of the current collector and the outside of the frame body.

2. 2. The bipolar storage battery according to claim 1, wherein the liquid permeation prevention member is a first liquid permeation prevention member provided along the frame in contact with the tab portion.

3. The bipolar storage battery of claim 2, characterized in that the liquid seepage prevention member further includes a second liquid seepage prevention member, which is arranged from both ends of the first liquid seepage prevention member toward the current collector and is arranged continuously along the peripheral portion of the current collector.

4. 2. The bipolar storage battery according to claim 1, wherein the liquid seepage prevention member is a resin that covers an area of ​​the tab portion from the peripheral edge of the current collector to the inside of the frame.

5. The bipolar storage battery according to claim 1 , wherein the tab portion is inserted into a tab insertion hole formed in the frame.

6. 6. The bipolar storage battery according to claim 1, wherein the current collector is made of lead or a lead alloy.

7. 2. The bipolar storage battery according to claim 1, wherein the frame has a frame cutout in which the tab is disposed.

8. 8. The bipolar storage battery according to claim 7, wherein the liquid seepage prevention member is a resin that covers an area of ​​the tab portion from the peripheral edge of the current collector to the frame cutout.

9. 9. The bipolar storage battery according to claim 8, wherein the resin disposed in the frame cutout portion of the liquid seepage prevention member has a height equal to the height of the frame.

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

11. a step of fabricating a pair of end plates by arranging a current collector on a substrate of an end plate by inserting a tab portion formed on the current collector into a tab insertion hole formed in the substrate; providing a liquid seepage prevention member in at least a portion of one or both of the pair of end plates between a peripheral edge of the current collector in the tab portion and an outer side of a frame of the end plate; a step of disposing a first active material layer so as to be in contact with the current collector disposed on one of the end plates on which the liquid seepage prevention member is provided; disposing a separator in contact with the first active material layer; disposing a second active material layer in contact with the separator; disposing the current collector so as to be in contact with the second active material layer; repeating the step of stacking the first active material layer, the separator, the second active material layer, and the current collector until a desired performance is obtained; a step of placing the other end plate obtained in the end plate manufacturing step; A method for manufacturing a bipolar storage battery, comprising:

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