JP2005135764A - Layer-built cell of bipolar plate method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a layer-built cell of bipolar plate method having simple structure and simple operability, superior in sealing characteristic against an electrolytic solution, with low-cost. <P>SOLUTION: On the layer-built cell of bipolar plate method, a plurality of single cells are connected in series electrically and mechanically, two adjacent single cells are partitioned by a bipolar plate, and the respective single cells are surrounded by a cell casing and the bipolar plate. The bipolar plate is provided with an erosion resistant metal plate and a synthetic resin layer covering the periphery thereof, and the bipolar plate is integrally molded and fixed to the cell casing made of the synthetic resin through the synthetic resin layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bipolar plate type laminated battery. More specifically, in a stacked battery in which a plurality of single cells are stacked in series, each power generation element is partitioned by a cell casing and a bipolar plate integrally formed through a portion at least partially covered with a synthetic resin. The present invention relates to a bipolar battery.

  An assembled battery used as a power source for an electric vehicle or a power storage power source. An assembled sealed secondary battery having high mechanical strength, no corrosion of the connection between single cells, and high weight energy density and volume energy density. For example, Japanese Patent Application Laid-Open No. H10-228667 discloses a technology subject to providing the above.

  In Patent Document 1, in manufacturing an assembled battery, first, two electrode plate groups are manufactured, a positive electrode current collector plate is welded to both ends thereof, and a soft viscous sealant is applied in parallel with the manufacture of the electrode plate groups. The electrical connection body in which an O-ring is installed in the attached holding groove is press-fitted into a partition wall in which a soft-viscous sealant has been applied in advance to the portion that is press-contacted with the O-ring, and the electrical connection body is pressed into and secured to the partition wall. It is described that it may be fixed by insert molding instead.

  In addition, the technical problem of providing a battery power supply device that can improve the support strength and rigidity of the battery module and can be easily incorporated into the holder case without erroneous insertion is, for example, It is disclosed in Patent Document 2.

  In Patent Document 2, a large number of battery modules, in which a plurality of single cells are electrically and mechanically connected in series in a row, are arranged in parallel and held in a holder case, and positioned at both ends of the holder case. A battery power supply device in which a metal pass bar for electrically connecting the terminals of the battery module is provided on each end plate is disclosed. The end plate is made of a resin plate, and the pass bar is inserted into the end plate by insert molding. It is fixed.

JP 2002-83576 A (page 4-5, FIG. 9) Japanese Patent Laid-Open No. 10-270006 (pages 6-8, FIG. 12)

  In the case of the collective sealed secondary battery disclosed in Patent Document 1, in order to ensure sealing performance, a holding groove is provided in the electrical connection body, and a soft viscous sealant is applied to the holding groove to install an O-ring. Then, the electrical connection body is press-fitted into a partition wall in which a soft-viscous sealant is applied in advance to a portion that is press-contacted with the O-ring. Therefore, the structure is complicated and the workability is also complicated.

  In addition, Patent Document 1 describes that the electrical connection body may be fixed by insert molding instead of being press-fitted into the partition wall, but when the electrical connection body is fixed to the partition wall by insert molding. No specific means for ensuring the adhesion of the electrical connection body to the partition walls is disclosed.

  On the other hand, Patent Document 2 only describes that a metal pass bar for electrically connecting the terminals of the battery module to the end plate is fixed to the end plate made of synthetic resin by insert molding. No specific means for ensuring adhesion to the plate is disclosed.

  In addition, the bipolar plate type laminated battery is advantageous in improving the weight energy density, volume energy density, and volume energy density, and has a small electrical resistance between each single cell, and is advantageous for high-rate charge / discharge. A special sealing method using an O-ring or the like is necessary to ensure the resistance. For this reason, the structure is complicated, and the assembly work of the battery is also complicated.

  An object of the present invention is to provide a bipolar plate type laminated battery that solves such conventional problems, has a simple structure, has a simple workability, has a good sealing property against an electrolyte, and is low in cost. Is.

In the first aspect of the present invention, a plurality of single cells are electrically and mechanically connected in series, two adjacent single cells are partitioned by a bipolar plate, and each single cell is surrounded by a cell casing and a bipolar plate. Bipolar plate type laminated battery,
The bipolar plate includes a corrosion-resistant metal plate and a synthetic resin layer coated on the periphery thereof,
The bipolar battery is characterized in that the bipolar plate is fixed to a cell casing made of synthetic resin through the synthetic resin layer by integral molding.

In the second aspect of the present invention, a plurality of single cells are electrically and mechanically connected in series, two adjacent single cells are partitioned by a bipolar plate, and each single cell is surrounded by a cell casing and a bipolar plate. Bipolar plate type laminated battery,
The bipolar plate includes a steel plate layer, a corrosion-resistant plating or corrosion-resistant coating layer provided on both surfaces of the steel plate layer, and a synthetic resin layer coated around the corrosion-resistant plating or corrosion-resistant coating layer,
The bipolar battery is characterized in that the bipolar plate is fixed to a cell casing made of synthetic resin through the synthetic resin layer by integral molding.

In the third aspect of the present invention, a plurality of single cells are electrically and mechanically connected in series, two adjacent single cells are partitioned by a bipolar plate, and each single cell is surrounded by a cell casing and a bipolar plate. Bipolar plate type laminated battery,
The bipolar plate includes a corrosion-resistant metal plate and a synthetic resin layer coated on a side edge of the corrosion-resistant metal plate,
The bipolar type laminated battery is characterized in that the bipolar plate is fixed at least partially by a synthetic resin cell casing through the synthetic resin layer by integral molding.

According to a fourth aspect of the present invention, a plurality of single cells are electrically and mechanically connected in series, two adjacent single cells are partitioned by a bipolar plate, and each single cell is surrounded by a cell casing and a bipolar plate. Bipolar plate type laminated battery,
The bipolar plate comprises a corrosion-resistant metal plate;
Provide a bent portion at the end of the bipolar plate,
At least one surface of the bent portion of the bipolar plate is covered with a thermoplastic resin layer,
The bent portion of the bipolar plate is embedded in the cell casing, and is fixed at least partially by synthetic molding with the synthetic resin cell casing through the synthetic resin layer,
The bipolar plate battery is characterized in that a bent portion of the bipolar plate is a non-flat body.

  The non-flat body is preferably a means for preventing the bipolar plate from falling out of the cell casing.

  Moreover, it is preferable that the means for preventing the bipolar plate from falling out of the cell casing is a bent portion formed in a wave shape.

  Moreover, it is preferable that the means for preventing the bipolar plate from falling out of the cell casing is a bent portion that is folded once or twice or more.

  Moreover, it is preferable that the means for preventing the bipolar plate from coming off from the cell casing is a bent portion formed in a wave shape that is folded once or twice.

  Further, it is preferable that one or two or more holes are formed in the bent portion of the bipolar plate.

  As the corrosion resistant metal used in the bipolar plate of the present invention, nickel, nickel alloy, stainless steel, titanium and the like are preferable.

  Further, as the anticorrosion coating used in the present invention, nickel plating, chrome plating, noble metal plating and the like are preferable.

  The synthetic resin used for the bipolar plate and the cell casing of the present invention is preferably a general-purpose resin. For example, polyolefin resins represented by polyethylene and polypropylene, vinyl resins such as polyvinyl chloride and acrylic resins, and acrylic resins are inexpensive. It is excellent in alkali resistance and is particularly preferable. Further, polyamide, polyurethane and the like can be used, and epoxy resin and the like can also be used.

  Chemical-resistant rubber can be used in place of the synthetic tree.

A fifth aspect of the present invention is an integral molding method for fixing a bipolar plate of the laminated battery of the bipolar plate type and a cell casing made of synthetic resin via a synthetic resin layer, the cell casing cell It is characterized in that the force when the bipolar plate comes out of the casing can be 1 kgf or more per 1 cm ^{2 of} the contact area.

  ADVANTAGE OF THE INVENTION According to this invention, the structure of the bipolar plate system laminated battery which is excellent in mechanical strength without the leakage of electrolyte solution can be provided.

  In addition, the present invention is particularly effective for a battery using a highly corrosive alkaline electrolyte. Further, in a battery characterized by high rate charge / discharge, such as a nickel metal hydride battery, the advantages of the bipolar plate method are fully utilized. It is extremely effective because it can.

  The structure of the bipolar plate type laminated battery of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiment shows a specific example of the present invention, but the scope of the present invention is not limited to the embodiment.

  FIG. 1 is a cross-sectional explanatory view showing a part of the structure of a bipolar plate type laminated battery according to an embodiment of the present invention, and FIG. 2 shows the structure of a bipolar plate type laminated battery according to another embodiment of the present invention. FIG. 3 is a cross-sectional explanatory view showing a modification of the structure of FIG. 2, FIG. 4 is a cross-sectional explanatory view showing another modification of the structure of FIG. 2, and FIG. FIG. 6 is a partially cutaway perspective view showing the internal structure of the plate type laminated battery, FIG. 6 is an explanatory view showing the appearance of the laminated battery of FIG. 6, and FIG. 7 is an explanatory view showing an example of the structure of the bipolar plate with respect to the cell casing. 8 is an explanatory view showing another example of the structure of the bipolar plate relative to the cell casing, and FIGS. 9 to 16 are explanatory views showing still another example of the structure of the bipolar plate relative to the cell casing.

  5 and 6, reference numeral 4 is a cell casing, reference numeral 5 is a minus (−) side current collector, reference numeral 6 is a plus (+) side current collector, reference numeral 8 is a positive electrode, and reference numeral 9 is a negative electrode. Reference numeral 7 denotes a separator interposed between the positive electrode 8 and the negative electrode 9, and reference numeral M denotes a bipolar plate.

  As shown in FIGS. 5 and 6, in the bipolar plate type stacked battery, the space defined by the minus side current collector plate 5, the plus side current collector plate 6 and the cell casing 4 is partitioned by a plurality of bipolar plates M. It is obtained by tightening a plurality of cells defined by the bolts and nuts 10 (in the case of FIGS. 5 and 6, it is composed of four cells).

Embodiment 1
Referring to FIG. 1, the structure of a bipolar plate type laminated battery of the present invention includes a bipolar plate M provided with a nickel plating layer 2 on both surfaces 1x and 1y of a steel plate 1. The periphery P of the bipolar plate M is covered with the polypropylene layer 3. In FIG. 1, a portion having a substantially U-shaped cross section is a polypropylene layer 3. Thus, since the polypropylene layer 3 is provided in the periphery P of the bipolar plate 3, the polypropylene layer 3 and the cell casing 4 made of polypropylene can be fixed by integral molding. In the case of the present embodiment, as shown in FIG. 1, the end surface 3 e and the side edge 3 m of the polypropylene layer 3 in the periphery P of the bipolar plate M and the surface R in the recess formed in the cell casing 4 are integrated. It is firmly fixed by molding.

  Moreover, in the bipolar plate M of this Embodiment, it can replace with a polypropylene layer and can also be set as the rubber layer which has chemical resistance.

  Since the structure of the bipolar plate type laminated battery according to the present embodiment has the above-described configuration, for example, the entire bottom surface of the space surrounded by the cell casing 4 (that is, the unit cell (or cell) C) is made of nickel. A plating layer can be used, and an aqueous potassium hydroxide solution (that is, an electrolytic solution) does not leak from the junction between the bipolar plate M and the cell casing 4.

  Therefore, according to the structure of the bipolar plate type laminated battery of the present invention, the unit cell C can be made a completely closed space with high sealing performance, and the adhesion between the bipolar plate M and the cell casing 4 is improved. can do.

Embodiment 2
Referring to FIG. 2, in the present embodiment, both surfaces 1x and 1y of the steel plate 1 constituting the bipolar plate M are covered with the nickel plating layer 2. A polypropylene layer 3 is provided on the side edge Mm on the nickel plating layer 2. With this configuration, the side edge 3m and end surface 3e of the polypropylene layer 3 and the recess formed in the cell casing 4 made of polypropylene around the bipolar plate M (that is, the side edge Mm on the nickel plating layer 2 of the bipolar plate M). Is firmly fixed to the surface R by integral molding. A rubber layer having chemical resistance can be used instead of the polypropylene layer.

  FIG. 3 shows a modification of the structure of the bipolar plate type stacked battery shown in FIG. In the case of this modification, in addition to the polypropylene layer 3 provided on the side edge on the nickel plating layer 2 of the bipolar plate M shown in FIG. 2, the polypropylene layer 3 is also provided on the end surface Me of the bipolar plate M. Therefore, it can be fixed by integral molding with a polypropylene cell casing. A rubber layer having chemical resistance can be used instead of the polypropylene layer.

  For this reason, the adhesiveness between the cell casing 4 and the bipolar plate M is further improved.

  FIG. 4 shows still another modification of the structure of the bipolar plate type laminated battery shown in FIGS. In the case of this modification, in addition to the two polypropylene layers (or rubber layers having chemical resistance) 3 as shown in FIG. Since the rubber layer 3 having chemical properties is provided, it can be fixed to the polypropylene cell casing by integral molding. For this reason, the adhesiveness between the cell casing 4 and the bipolar plate M is further improved.

  In the case of the present embodiment, as shown in FIGS. 2 to 4, the polypropylene layer is accommodated in a recess provided in the cell casing, and there is no portion protruding outside the cell casing 4. For this reason, the entire surface of the bipolar plate M can be used as an electrode plate.

Embodiment 3
In the above-described first and second embodiments, the configuration of the bipolar plate M that is firmly fixed to the cell casing 4, which is a feature of the present invention, has been described. In the present embodiment, using the bipolar plate M of the first and second embodiments and the modifications thereof, a laminated battery that is easy to assemble and has excellent adhesion, mechanical strength, and electrolyte sealing properties is obtained. The configuration for this will be described in detail below.

  FIG. 7 shows a state in which the bipolar plate M described in the second embodiment is fixed to the cell casing 4. In FIG. 7, reference numeral 3 indicates a synthetic resin coating layer.

  For each unit cell, the bipolar plate M shown in FIG. 7 is integrally formed through the cell casing 4 and the synthetic resin coating layer 3, and a plurality of unit cells are stacked to obtain a bipolar plate type stacked battery.

  In FIG. 8, the bipolar plate M and the cell casing 4 are not integrally formed for each unit cell, but the cell casing 4 and the plurality of bipolar plates M, which are the skeleton of the laminated battery, are integrated through the synthetic resin coating layer 3. A bipolar plate type laminated battery is obtained by molding.

  FIG. 9 shows a modification of the structure shown in FIG. In the structure shown in FIG. 7, since the right end of the cell casing 4 protrudes with respect to the bipolar plate M, it becomes a hindrance when assembling the cells, and the assembly of the cells is somewhat complicated. On the other hand, in the structure shown in FIG. 9, the end portion of the bipolar plate M is bent, and this bent portion is embedded in the longitudinal direction of the cell casing 4 from the end surface of the cell casing 4. There is no protrusion for the bipolar plate M. For this reason, there exists an advantage that the assembly of single cells becomes easy.

  10 to 11 show a modification of the structure of FIG. 9, and FIG. 12 shows a modification of the structure of FIGS.

In the case of FIG. 10, the bent portion of the bipolar plate M embedded in the cell casing 4 is a non-flat body, that is, a curved surface formed in a wave shape, and in the case of FIGS. 11 and 12, the bent portion of the bipolar plate M is the cell casing. It is folded once within 4. The number of folds is not limited to one, but may be folded twice or more (see FIG. 16). As shown in FIG. 16, a more robust structure can be realized by folding the bent portion of the bipolar plate M twice. Further, by making the bent portion non-flat as shown in FIGS. 10 and 16, the bent portion of the bipolar plate M embedded in the cell casing 4 is prevented from coming off. That is, when the bent portion is employed, the contact surface between the cell casing 4 and the bipolar plate M can be increased by integrally molding the cell casing 4 and the bipolar plate M, and the adhesion of the bipolar plate M to the cell casing 4 can be increased. In addition, the mechanical strength of the bipolar plate type laminated battery of the present invention can be improved. The force when the bent part of the bipolar plate M comes out is 1 kgf or more per 1 cm ² of the contact area. Moreover, when a bending part is employ | adopted, the sealing performance of electrolyte solution can also be improved.

  In the case of FIG. 13, the length of the bent portion of the bipolar plate M embedded in the cell casing 4 in the longitudinal direction of the cell casing is long. For this reason, when the bipolar plate M having such a long bent portion and the cell casing 4 are integrally formed, the bent portion of the bipolar plate M can function as a reinforcing member for the cell casing 4.

  In the case of FIGS. 14 and 15, one or more round holes H (see FIG. 14) or square holes R (see FIG. 15) are formed in the bent portion of the bipolar plate embedded in the cell casing 4. When the cell casing 4 and the bent portion of the bipolar plate are integrally formed, the synthetic resin fills the round hole H or the square hole R, and the adhesion and mechanical strength between the bipolar plate M and the cell casing are further improved.

  10 to 15 functions as prevention means or locking means for preventing the bending portion of the bipolar plate from coming off from the cell casing 4.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

  Open the mold for injection molding, sandwich a nickel-plated steel sheet of 52 mm in length, 52 mm in width, and 0.45 mm in thickness into the mold, close the mold, and then flow polypropylene into the mold. By injection molding (insert molding method), the nickel-plated steel sheet having a length of 52 mm, a width of 52 mm, and a thickness of 0.45 mm is fixed to a polypropylene casing having an outer dimension of 44 mm and an inner dimension of 44 mm. After filling with potassium hydroxide, pressure was applied to the inside of the casing to check for electrolyte leakage. As a result, it was found that electrolyte leakage occurred at a pressure of 5 kPa.

  Next, the outer peripheral portion of a nickel-plated steel plate having a length of 52 mm, a width of 52 mm, and a thickness of 0.45 mm is inserted into a polypropylene casing having an outer dimension of 44 mm and an inner dimension of 44 mm by the insert molding method described above. After molding and filling the casing with 8N potassium hydroxide, pressure was applied to the inside of the casing to check for electrolyte leakage. As a result, it was found that no electrolyte leakage occurred up to a pressure of 100 kPa.

  Further, an alkali-resistant rubber (EPDM) is arranged on the outer periphery of a nickel-plated steel sheet having a length of 52 mm, a width of 52 mm, and a thickness of 0.45 mm, and a polypropylene casing having an outer dimension of 44 mm and an inner dimension of 44 mm is formed by the insert molding method described above. After insert molding, the casing was filled with 8N potassium hydroxide, and then the inside of the casing was pressurized to check for electrolyte leakage. As a result, it was found that no electrolyte leakage occurred up to a pressure of 100 kPa.

1 is a cross-sectional explanatory view showing a part of the structure of a bipolar plate type laminated battery according to an embodiment of the present invention. FIG. 5 is a cross-sectional explanatory view showing a part of the structure of a bipolar plate type laminated battery according to another embodiment of the present invention. FIG. 3 is a cross-sectional explanatory view showing a modification of the structure of FIG. 2. FIG. 10 is a cross-sectional explanatory view showing another modification of the structure of FIG. 2. FIG. 5 is a partially cutaway perspective view showing the internal structure of a general bipolar plate type laminated battery. It is explanatory drawing which shows the external appearance of the laminated battery of FIG. It is explanatory drawing which shows an example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the other example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing. It is explanatory drawing which shows the further another example of the structure of the bipolar plate with respect to a cell casing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel plate 1x One side of steel plate 1y The other side of steel plate 2 Nickel plating layer 3 Polypropylene layer 3e End face of polypropylene layer 3m Side edge of polypropylene layer 4 Cell casing 5 Minus (-) side current collector plate 6 Plus (+) side Current collector plate 7 Separator 8 Positive electrode 9 Negative electrode C Single cell M Bipolar plate Me End face of bipolar plate Mm Side edge of bipolar plate P Peripheral of bipolar plate R Wall of recess

Claims (11)

A bipolar plate type stacked battery in which a plurality of cells are electrically and mechanically connected in series, two adjacent cells are separated by a bipolar plate, and each cell is surrounded by a cell casing and a bipolar plate. And
The bipolar plate includes a corrosion-resistant metal plate and a synthetic resin layer coated on the periphery thereof,
A bipolar type laminated battery, wherein the bipolar plate is fixed to a cell casing made of synthetic resin through the synthetic resin layer by integral molding. A bipolar plate type stacked battery in which a plurality of cells are electrically and mechanically connected in series, two adjacent cells are separated by a bipolar plate, and each cell is surrounded by a cell casing and a bipolar plate. And
The bipolar plate includes a steel plate layer, a corrosion-resistant plating or corrosion-resistant coating layer provided on both surfaces of the steel plate layer, and a synthetic resin layer coated around the corrosion-resistant plating or corrosion-resistant coating layer,
A bipolar type laminated battery, wherein the bipolar plate is fixed to a cell casing made of synthetic resin through the synthetic resin layer by integral molding. A bipolar plate type stacked battery in which a plurality of cells are electrically and mechanically connected in series, two adjacent cells are separated by a bipolar plate, and each cell is surrounded by a cell casing and a bipolar plate. And
The bipolar plate includes a corrosion-resistant metal plate and a synthetic resin layer coated on a side edge of the corrosion-resistant metal plate,
A bipolar type laminated battery characterized in that the bipolar plate is fixed at least partially by a synthetic resin cell casing through the synthetic resin layer by integral molding. A bipolar plate type stacked battery in which a plurality of cells are electrically and mechanically connected in series, two adjacent cells are separated by a bipolar plate, and each cell is surrounded by a cell casing and a bipolar plate. And
The bipolar plate comprises a corrosion-resistant metal plate;
Provide a bent portion at the end of the bipolar plate,
At least one surface of the bent portion of the bipolar plate is covered with a synthetic resin layer,
The bent portion of the bipolar plate is embedded in the cell casing, and is fixed at least partially by synthetic molding with the synthetic resin cell casing through the synthetic resin layer,
A bipolar type laminated battery, wherein a bent portion of the bipolar plate is a non-flat body. The laminated battery according to claim 4, wherein the non-flat body is a means for preventing the bipolar plate from falling out of the cell casing. 6. The laminated battery according to claim 5, wherein the means for preventing the bipolar plate from falling out of the cell casing is a bent portion formed in a wave shape. 6. The laminated battery according to claim 5, wherein the means for preventing the bipolar plate from falling out of the cell casing is a bent portion that is folded back once or twice. 7. The laminated battery according to claim 6, wherein the means for preventing the bipolar plate from falling out of the cell casing is a bent portion formed in a wave shape that is folded once or twice. The laminated battery according to claim 4, wherein one or two or more holes are formed in the bent portion of the bipolar plate. A chemical-resistant rubber layer is provided in place of the synthetic resin layer.
, 7, 8 or 9 laminated battery. The bipolar plate of the bipolar plate type laminated battery according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 is fixed to a synthetic resin cell casing via a synthetic resin layer. An integral molding method characterized in that the force when the bipolar plate comes out of the cell casing cell casing can be 1 kgf or more per 1 cm ^{2 of} the contact area.

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