JP5086204B2 - Capacitor module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a capacitor module configured using a square electric double layer capacitor and a method for manufacturing the same.

  2. Description of the Related Art In recent years, attention has been focused on electric double layer capacitor application technologies that can be rapidly charged and have a long charge / discharge cycle life as power storage devices (Patent Documents 1 to 4). In a power storage device for a vehicle, a capacitor module is configured by connecting a plurality of electric double layer capacitors in series in order to secure a required capacity.

  FIG. 7 illustrates an example of the capacitor module. The electric double layer capacitor 10 is used as a unit cell, and a plurality of unit cells 10 are gathered in an aligned state overlapping in the thickness direction. The unit cell 10 includes a rectangular laminate composed of a positive electrode body, a negative electrode body, and a separator interposed therebetween, and a pair of leads connected to the positive electrode body and the negative electrode body, respectively. It is comprised from the terminal 11 and the container 12 which seals a laminated body with electrolyte solution in the state in which these terminals 11 protrude outside.

  In each unit cell 10, the pair of terminals 11 are bent in the opposite direction in the thickness direction (horizontal direction) of the unit cell 10. As for the terminals 11b to 11e connecting the adjacent unit cells, the tip side is further bent in a direction perpendicular to the thickness direction of the unit cell 10, and the tip portions facing each other are joined by welding or the like. The remaining terminal 11a (positive electrode side) of one unit cell 10 at both ends and the remaining terminal 11f (negative electrode side) of the other unit cell 10 are connected to the main terminal of the capacitor module.

  The capacitor module is housed in a case (not shown) made of an electrical insulating material. The case includes a capacitor module housing and a lid that detachably closes the opening. A pair of main terminals is disposed in the case and connected to the terminals 11a and 11f of the unit cell located at both ends.

  A control board is attached to the inside of the lid that covers the plane of the capacitor module. The control board has a number of bypass circuits corresponding to the unit cells connected in series, and monitors the voltage (cell voltage) between a pair of terminals for each unit cell connected in series with a set value. A control circuit that opens the bypass circuit when the voltage is equal to or lower than a set value and closes the bypass circuit when the cell voltage exceeds the set value. Wiring is provided to connect between each of the circuits and a pair of terminals of each unit cell.

When the bypass circuit is closed by such a control board, a part of the charging current flows through the bypass circuit, so that the voltage between the pair of terminals exceeds the set value. For this reason, by setting the set value to a value corresponding to the withstand voltage, a voltage increase (overcharge) exceeding the withstand voltage of the unit cell can be prevented.
JP 2007-103773 A JP 2000-082641 A Japanese Patent Laid-Open No. 10-074672 JP 10-055936 A

  In such a capacitor module, since the terminals 11b to 11e connecting between adjacent unit cells protrude outwardly perpendicular to the thickness direction of the unit cell 10, there is also a relationship with the control board, such as a lid portion. If these parts are included, there is a problem that it is easy to create a useless space in the height direction and it is difficult to secure the energy density per volume.

  An object of the present invention is to provide means for solving such a problem.

A first invention is a capacitor module in which a rectangular electric double layer capacitor is used as a unit cell and a plurality of unit cells are gathered in an aligned state overlapping in the thickness direction, and the unit cells are connected in series. Each unit cell includes a laminate composed of a positive electrode body, a negative electrode body, and a separator, a positive terminal connected to the collector electrode of the positive electrode body, and a negative terminal connected to the collector electrode of the negative electrode body And a container for accommodating the laminate together with the electrolyte, wherein one of the terminals extends to one of the unit cells in the thickness direction, and the other of the terminals extends to the other of the unit cells in the thickness direction. Each terminal connecting the unit cells is sealed in the adjacent partition walls of the container of the adjacent unit cells .

  According to a second aspect of the present invention, there is provided a capacitor module in which a rectangular electric double layer capacitor is used as a unit cell and a plurality of unit cells are gathered in an aligned state overlapping in the thickness direction and the unit cells are connected in series. A unit having a control board that restricts the voltage between a pair of terminals of each unit cell from exceeding a set value, and the unit cells are connected to the inside of an adjacent partition wall of each container of adjacent unit cells. Each terminal is sealed together with the control board.

According to a third aspect of the present invention, there is provided a capacitor module in which a rectangular electric double layer capacitor is used as a unit cell and a plurality of unit cells are gathered in an aligned state overlapping in the thickness direction and the unit cells are connected in series In the method, each unit cell includes a laminate composed of a positive electrode body, a negative electrode body, and a separator, a positive electrode terminal connected to the collector electrode of the positive electrode body, and a negative electrode connected to the collector electrode of the negative electrode body A plurality of unit cells are arranged in an aligned state overlapping in the thickness direction, and terminals between adjacent unit cells are joined to each other. a step of, prior to the step of bonding the terminals to each other between the unit cells, extend the one terminal of the respective unit cells to one thickness direction of the unit cells, also other thickness of the unit cell of the terminal Extended to the other direction, it comprises a step of sealing together with an electrolyte laminate in the container while sealed in the interior of the adjacent partition wall of the container of the unit cells adjacent to the terminals for connecting these unit cells It is characterized by.

  According to a fourth aspect of the present invention, there is provided a capacitor module in which a square electric double layer capacitor is used as a unit cell and a plurality of unit cells are gathered in an aligned state overlapping in the thickness direction and the unit cells are connected in series. In the method, a step of composing a laminate from a positive electrode body, a negative electrode body, and a separator, a step of connecting terminals corresponding to polarities to each of the positive electrode body and the negative electrode body of the laminate, and connecting these terminals together 1 A step of assembling a control board that restricts the voltage between the pair of terminals from exceeding a set value, and a state where each terminal and the control board are exposed inside the partition wall of the container, and the tips of these terminals are exposed on both sides in the thickness direction of the container. The process of sealing the laminate together with the electrolytic solution inside the container while containing, and arranging the unit cells in an aligned state overlapping in the thickness direction and adjoining the containers of the adjacent unit cells Characterized in that it comprises a step of bonding the tip of the terminals exposed on the surface from each other, the.

  In the first invention, since each terminal connecting the adjacent unit cells is enclosed in the adjacent partition wall of each unit cell container, a waterproof and dustproof cover for each terminal connecting the unit cells is used. Is no longer necessary. Each terminal connecting between adjacent unit cells is extended in the thickness direction of the unit cell to the adjacent surface of the container of the adjacent unit cell inside the partition wall of the container, and unlike the conventional case, the direction parallel to the adjacent surface of the container Does not protrude into As a result, since the size of the capacitor module can be kept small, the energy density per volume can be increased.

  In the second invention, in addition to the pair of terminals, the control board interposed therebetween is also enclosed in the partition wall of the container. In other words, unlike the conventional case, the control board is incorporated not inside the unit cell but inside the unit cell using the partition wall, so that the size of the capacitor module can be kept small and the energy density per volume can be further increased. Can do.

  In the third invention, the capacitor module according to the first invention can be efficiently manufactured.

  In the fourth invention, the capacitor module according to the second invention can be efficiently manufactured.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view of a capacitor module, which includes a control board (not shown). The capacitor module has a square electric double layer capacitor 20 as a unit cell, and a plurality of unit cells 20 are gathered in an aligned state overlapping in the thickness direction. 21a is a terminal (positive electrode side) of one unit cell 20 at both ends, and 21f is also a terminal (negative electrode side) of the other unit cell, which constitutes the main terminal of the capacitor module.

  The control board is for restricting the voltage between the pair of terminals from exceeding the set value, and the number of bypass circuits corresponding to the unit cells connected in series and the unit cells connected in series When the cell voltage is below the set value, the bypass circuit is opened while the voltage between the pair of terminals (cell voltage) is monitored by comparing with the set value, and when the cell voltage exceeds the set value, the bypass circuit is opened. And a control circuit for closing.

  The unit cell 20 is configured as shown in FIGS. FIG. 2 is a plan view of the unit cell 20a, and FIG. 3 is a cross-sectional view of the unit cell 20a or 20c taken along the line AA. The other unit cell 20b also has a basic configuration excluding the terminal 21 as described later. The configuration is set to be the same as that of the unit cell 20a or 20c.

  In FIG. 3, reference numeral 22 denotes a laminated body that constitutes a power storage unit, and is composed by alternately stacking a positive electrode body and a negative electrode body with a separator interposed therebetween. The positive electrode body and the negative electrode body are composed of a collector electrode and polarizable electrodes (activated carbon electrodes) on both sides thereof. The collector electrode is made of a rectangular metal foil (aluminum foil), and a strip-shaped lead is integrally formed on one side of the rectangular plane. Each lead is bundled with the same polarity and connected (welded) to a terminal having a corresponding polarity. The distal ends of the pair of terminals 21 b are bent in opposite directions with respect to the thickness direction of the unit cell 20 and inserted into the slit 24 of the container 23. Each terminal 21 is formed in a short shape from an aluminum plate.

  The container 23 of the unit cell 20 includes two container members 23a and 23b formed of a heat-welding electric insulating material. When these mating surfaces are abutted with each other, the two container members 23a and The accommodating part 25 of the laminated body 22 is formed between 23b. In the two container members 23a and 23b, a slit 24 for inserting the tip ends (portions extending in the thickness direction of the unit cells) of the terminals 21a and 21b on the corresponding sides of the mating surfaces surrounding the recesses, and the slit A recess 27 for receiving the flange portion 26 (see FIG. 5) of the heat sealer, and an electrolyte inlet and outlet (not shown) are provided above and below the gap 24.

  The laminated body 22 is formed by abutting the mating surfaces of the two container members 23a and 23b while inserting the distal ends of the pair of terminals 21 into the corresponding slits 24 between the two container members 23a and 23b. It is accommodated between the recesses of the two container members 23a, 23b.

  The mating surfaces (four sides surrounding the recess) of the two container members 23a and 23b are thermally welded by ultrasonic vibration. The slits 24 of the container 23 are thermally welded by inserting the flange portions 26a and 26b of the heat sealer into the recesses 27a and 27b sandwiching the slits 24 and pressing the recesses 27a and 27b with the respective heating surfaces. As a result, the base end sides of the pair of terminals 21 (portions extending in a direction parallel to the adjacent surface of the unit cell 20) are sealed in the heat-welded portion 28 that joins the mating surfaces of the container 23. The tip end side of 21 is enclosed in the heat welding part 29 of the slit 24. That is, the pair of terminals 21 are enclosed in the partition wall of the container 23 so that the tip of each terminal 21 is exposed on both surfaces of the container 23 in the thickness direction. Thereafter, the electrolytic solution is injected into the container 23, and the electrolytic solution inlet and the exhaust port are sealed in a predetermined vacuum state.

  2 and 3 is located at the end of the capacitor module, one of the pair of terminals 21 serves as the main terminal of the capacitor module from the other terminals in the alignment direction (thickness direction) of the unit cells 20. Is also long. For the other unit cell 20 located in the middle of the capacitor module, the pair of terminals 21 are set to have the same length. In FIG. 3, reference numeral 30 denotes a notch that forms a window portion for irradiating between the tips of the terminals 21 that are abutted against each other with a laser welding beam used for joining the terminals 21 of the adjacent unit cells 20. After the bonding between the terminals 21, the part is filled with the electrical insulating material 31 together with the upper concave portion 27a (see FIGS. 1 and 2).

  With such a configuration, the terminals 21 connecting the adjacent unit cells 20 are sealed in the adjacent partition walls of the containers 23 of the unit cells 20, so that the waterproofing is performed on the terminals 21 connecting the unit cells 20. And a dustproof cover are not required. Each terminal 21 connecting the adjacent unit cells 20 is extended in the thickness direction of the unit cell 20 to the adjacent surface of the container 23 of the adjacent unit cell 20 through the inside of the partition wall of the container 23. It does not protrude in the direction parallel to the adjacent surface. As a result, since the size of the capacitor module can be kept small, the energy density per volume can be increased.

  The control board can be placed on the plane of the assembly (capacitor module) of unit cells 20. In that case, the connection (wiring) between the unit cell 20 and the control board can be processed through the window part before filling with the electrical insulating material.

  It is conceivable that the control board is divided for each of the unit cells 20a to 20c and built in for each of the unit cells 20a to 20c. For example, in each unit cell 20, a control board is disposed between a pair of terminals 21, and each electrical connection portion of the control board is connected to a terminal 21 having a corresponding polarity. Then, a protective patch (not shown) is attached to the control board, and the control board is sealed in a heat welding portion that joins the mating surface of the container 23 together with the pair of terminals 21. The protective patch is for protecting the control board from heat and pressure during ultrasonic vibration.

  As described above, since the control board is also built in the container 23, it is not exposed to the external environment, the failure is reduced, and the control board is not required to be waterproof or dustproof. In addition, the control board is sealed by using the heat-welded portion of the mating surface of the container 23, so that the electrical insulation with the electrolyte can be ensured satisfactorily without touching the electrolyte.

  Based on FIGS. 4-6, the manufacturing method of a capacitor module is demonstrated.

  4 and 5 show a state in which the pair of terminals 21 are exposed inside the partition wall of the container 23 and the tips of the terminals 21 are exposed on both sides in the thickness direction of the container 23 in the manufacturing process of the unit cell 20 (20a to 20c). The process of sealing the laminated body 22 with the electrolytic solution inside the container 23 while enclosing in FIG.

  In FIG. 4, reference numerals 23a and 23b denote two container members formed of a heat-welding electric insulating material, and a pair of layers 22 is positioned between them while facing each other's recesses. While the distal end side which is bent at right angles to the base end side of the terminal 21 and extends in the thickness direction of the unit cell 20 is inserted into the slit 24 of the container members 23a and 23b, the mating surfaces of the container members 23a and 23b are butted together. The

  In order to improve the adhesiveness between each terminal 21 and the container 23 (heat-welding electrical insulating material), a resin coating layer 32 is applied to each terminal 21 in advance. Reference numeral 33 denotes a welding rib formed integrally with the mating surface of the container member 23a in order to enhance the weldability of the mating surfaces of the container members 23a and 23b.

  In FIG. 5, the laminated body 22 is accommodated between the hollow parts of the two container members 23a and 23b by abutting the mating surfaces of the two container members 23a and 23b. By applying ultrasonic vibration to the two container members 23a and 23b, the mating surfaces of the two container members 23a and 23b and the resin coating layer of each terminal 21 are thermally welded. Also, the heat sealer flanges 26a and 26b are inserted into the upper and lower recesses 27a and 27b, and the recesses 27a and 27b are pressed on the respective heating surfaces, whereby the resin coating layer of each terminal 21 and the electrical insulating material of the container member 23b are obtained. Heat weld.

  With these treatments, the base end side of the pair of terminals 21 is sealed in the heat welding portion that joins the mating surfaces of the container 23, and the tip end side of the pair of terminals 21 is in the heat welding portion with the slit 24. Contained. That is, the pair of terminals 21 are enclosed in the partition wall of the container 23 so that the tip of each terminal 21 is exposed on both surfaces of the container 23 in the thickness direction. In FIG. 5, 34 is an ultrasonic vibration horn, and 35 is a jig facing the horn 34. Note that the illustration of the jig facing the horn 34a is omitted.

  FIG. 6 shows that the plurality of unit cells 20 are arranged in an overlapping state in the thickness direction and the tips of the terminals 21b, 21c, 21d, 21e exposed on the adjacent surfaces of the containers 23 of the adjacent unit cells 20 are mutually connected. The process of joining is illustrated.

  In FIG. 6, three unit cells 20a to 20c are arranged in an aligned state overlapping in the thickness direction. Reference numeral 36 denotes a module case that accommodates an assembly of these unit cells, and is formed in a box shape from an electrical insulating material. The tips that abut each other between the terminal 21b (negative electrode side) of the unit cell 20a located at the front end of the assembly and the terminal 21c (positive electrode side) of the unit cell 20b located in the middle are joined by laser welding. Further, the terminal 21d (negative electrode side) of the unit cell 20b located in the middle of the assembly and the terminal 21e (positive electrode side) of the unit cell 20c located at the rear end are joined by laser welding. In FIG. 6, reference numeral 38 denotes a lens for converging a laser welding beam.

  After that, when the electrical insulating material 31 is filled in the laser welding window and the upper recess, the capacitor module shown in FIG. 1 is obtained. A control board (not shown) is placed on an assembly of unit cells 20, and connection (wiring) between the unit cells 20 and the control board is processed through a window part before filling with the electrical insulating material 31.

  When one control board divided for each unit cell 20a to 20c is built in for each unit cell 20a to 20c, the control board is interposed between a pair of terminals 21 prior to the step of FIG. . That is, each electrical connection portion of the control board is connected to the base end side of the terminal 21 corresponding to each polarity. 4 and 5, the protective patch is attached to the control board, and this is sealed in a heat welding portion that joins the mating surfaces of the container 23 together with the pair of terminals 21.

  Based on such a manufacturing method, a capacitor module in which a control board is mounted on a plane of an assembly of unit cells 20a to 20c or a capacitor module in which one control board is built in each unit cell 20a to 20c is efficiently obtained. Can be manufactured.

  1 and 6, an aggregate composed of three unit cells 20 is provided, but the number of unit cells in the aggregate is of course not limited.

It is a perspective view explaining the structure of the capacitor module which concerns on embodiment of this invention. It is a top view explaining the structure of a unit cell similarly. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2. It is explanatory drawing which similarly illustrates the manufacturing process of a capacitor module. It is explanatory drawing which similarly illustrates the manufacturing process of a capacitor module. It is explanatory drawing which similarly illustrates the manufacturing process of a capacitor module. It is explanatory drawing of a prior art.

Explanation of symbols

20 (20a-20c) unit cell (electric double layer capacitor)
21 (21a to 21f) Unit cell terminal 22 Laminated body 23 Container 23a, 23b Container member 24 Slit 26 (26a, 26b) Heat sealer flange 27 (27a, 27b) Heat sealer recess 28, 29 Thermal welded part 30 Laser Notch for welding 31 Filler (electrical insulation)
32 Resin coating layer 33 Welding rib

Claims (4)

In a capacitor module configured by using a square electric double layer capacitor as a unit cell, a plurality of unit cells are gathered in an aligned state overlapping in the thickness direction, and the unit cells are connected in series.
Each unit cell includes a laminate composed of a positive electrode body, a negative electrode body, and a separator, a positive terminal connected to the collector electrode of the positive electrode body, and a negative terminal connected to the collector electrode of the negative electrode body And a container for storing the laminate together with the electrolytic solution,
One of the terminals is extended to one of the unit cells in the thickness direction, and the other of the terminals is extended to the other of the unit cells in the thickness direction. Capacitor module characterized by enclosing each terminal connecting between unit cells . In a capacitor module configured by using a square electric double layer capacitor as a unit cell and a plurality of unit cells being arranged in an overlapping state in the thickness direction and connecting these unit cells in series, a pair of each unit cell Each having a control board that restricts the voltage between the terminals of the adjacent unit cells from exceeding a set value. Capacitor module characterized by being contained. In a method for manufacturing a capacitor module, in which a rectangular electric double layer capacitor is used as a unit cell, a plurality of unit cells are gathered in an aligned state overlapping in the thickness direction, and the unit cells are connected in series.
Each unit cell includes a laminate composed of a positive electrode body, a negative electrode body, and a separator, a positive terminal connected to the collector electrode of the positive electrode body, and a negative terminal connected to the collector electrode of the negative electrode body And a container for storing the laminate together with the electrolytic solution,
A step of arranging a plurality of unit cells in an aligned state overlapping in the thickness direction and bonding terminals between adjacent unit cells;
Prior to the step of joining the terminals between the unit cells, one of the terminals of each unit cell is extended to one side in the thickness direction of the unit cell, and the other of the terminals is extended to the other side in the thickness direction of the unit cell. Sealing the laminate together with the electrolyte inside the container while enclosing each terminal connecting the unit cells in the adjacent partition wall of the container of the adjacent unit cell ;
A method for manufacturing a capacitor module, comprising: In a method of manufacturing a capacitor module, in which a rectangular electric double layer capacitor is used as a unit cell, a plurality of unit cells are gathered in an aligned state overlapping in the thickness direction, and the unit cells are connected in series. A step of composing a laminate from a negative electrode body and a separator, a step of connecting terminals corresponding to polarities to the positive electrode body and the negative electrode body of the laminate body, and a voltage between a pair of terminals by connecting these terminals The process of assembling a control board that restricts the value from exceeding the set value and the terminals and the control board inside the container bulkhead while the tips of these terminals are exposed on both sides in the thickness direction of the container. The step of sealing the laminate together with the electrolytic solution, the plurality of unit cells are arranged in an aligned state overlapping in the thickness direction, and exposed to the adjacent surfaces of the containers of the adjacent unit cells. Method of manufacturing a capacitor module, characterized in that it comprises a step of bonding the tip of the pin to each other, the.

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