JP2013105976A - Electrical storage device module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical storage device module which has small electrical resistance in a connection part, is excellent in electrode heat generation suppression and output characteristic improvement effect, and has small size and high productivity.SOLUTION: In an electrical storage device module comprising a plurality of storage cells 1, the storage cells 1 are connected one another by contacting and sandwiching a conductive material 4 between cell terminals 2 and 3 of the adjacent storage cells 1.

Description

  The present invention relates to a power storage device module formed by connecting a plurality of power storage cells.

  A power storage device such as an electric double layer capacitor, a lithium ion capacitor, or a lithium ion battery is used as a module by connecting a plurality of power storage cells as necessary.

  In Patent Document 1, in the modularization of a plurality of cells, the connection part that connects the electrodes of adjacent cells overlaps the electrodes formed in a plate shape, and adds these plate pressures to the rivet connection. By welding by laser welding, TIG welding, or spot welding, the electrical resistance of the connecting portion is reduced, and a high output density is achieved.

  According to Patent Document 2, the lead electrodes of a plurality of cells are formed in an L shape and overlapped, and then the lead electrodes are fixed together with a blind rivet and welded with a YAG laser to electrically reduce resistance. It is possible to connect to.

  In Patent Document 1, when connecting the electrodes of adjacent cells, if the thickness of the cell is large, it is necessary to increase the electrode length and connect at the tip. For this reason, there is a problem that the module size becomes large. Furthermore, when the thickness of the electrode is small, high welding accuracy is required, and there is a concern about poor quality.

  Further, in both Patent Document 1 and Patent Document 2, when connecting electrodes of adjacent cells, it is necessary to separately perform mechanical fastening by rivets and welding. Furthermore, the electrodes must be connected one by one, and the connection time is greatly affected by the number of cells. In addition, Patent Document 2 also includes a step of forming the terminal into an L shape. For these reasons, much time is required for the connection process, and low productivity is a problem.

Japanese Patent Laid-Open No. 2003-272966 JP 2010-232573 A

  The present invention has been made in view of the above-described problems of the prior art, and has a small electrical resistance device module with low electrical resistance at the connecting portion, excellent electrode heat generation suppression and output characteristics improvement effect, and is small and highly productive. The purpose is to provide.

  An electricity storage device module of the present invention that solves the above problem is an electricity storage device module comprising a plurality of electricity storage cells, wherein the electricity storage cells are connected by interposing a conductive material between the cell terminals of adjacent electricity storage cells. It is characterized by.

  Further, the method for producing the electricity storage device module of the present invention is a method for producing an electricity storage device module comprising a plurality of electricity storage cells, wherein the cell terminals of the plurality of electricity storage cells are aligned and overlapped. And a step of disposing a conductive material between cell terminals of adjacent power storage cells, and a step of bringing the cell terminals into contact with the disposed conductive material to connect the power storage cells to each other.

  In the electricity storage device module of the present invention, the electrical resistance in the connecting portion is small, and the electrode heat generation is suppressed and the output characteristics are improved. Furthermore, since the module dimensions are not affected by the cell thickness, downsizing can be realized and the productivity is high.

It is a front external view which shows an example of the electrical storage cell which comprises the electrical storage device module of this invention. It is sectional drawing which cut | disconnected the tab terminal of the electrical storage device module which concerns on 1st embodiment of this invention horizontally, and was seen from the top. It is a side view of the electrical storage device module which concerns on 1st embodiment of this invention. It is a figure explaining the case where a flat conductive material is used. It is a figure explaining the case where the electrically conductive material which has the surface shape used as line contact is used. It is sectional drawing which cut | disconnected the tab terminal of the electrical storage device module which concerns on 2nd embodiment of this invention horizontally, and was seen from the top.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front external view showing an example (single cell 1) of a power storage cell constituting the power storage device module of the present invention. A rectangular unit cell 1 having a certain thickness has a plate-like positive electrode tab terminal 2 and a negative electrode tab terminal 3 at predetermined positions in the upper part as cell terminals. Specific examples of the storage cell include an electric double layer capacitor, a lithium ion capacitor, and a lithium ion battery.

  FIG. 2 is a cross-sectional view of the tab terminal of the electricity storage device module according to the first embodiment of the present invention cut horizontally and seen from above, and FIG. 3 is a side view thereof.

  The power storage device module shown in FIGS. 2 and 3 uses a lithium ion capacitor as a power storage cell, and a plurality of rectangular single cells 1 are stacked in the same direction so that the terminals are aligned. The conductive material 4 is disposed between adjacent terminals, and the conductive material 4 is held in contact so that the contact surfaces are in contact with each other, thereby connecting the cells. There is no restriction | limiting in particular in the number of the single cells 1 which comprise an electrical storage device module, The number as needed can be combined. In this embodiment, a parallel connection in which a conductive material 4 is sandwiched between all adjacent terminals of a positive electrode tab terminal 2 made of an aluminum material and a negative electrode tab terminal 3 made of a nickel-plated copper material, which corresponds to a cell terminal. It is said. Since the conductive material is held in contact between adjacent cell terminals, the contact area between the cell terminal and the conductive material can be increased, and thus the current-carrying area between the cell terminals can be increased. The electrical resistance at the portion can be reduced, and the effect of suppressing electrode heat generation and improving the output characteristics can be obtained. Further, in order to ensure the contact between the cell terminals and the conductive material and ensure the conduction between the cell terminals, the fixing tab 5 binds the positive electrode tab terminals 2 and the negative electrode tab terminals 3 together. The method of ensuring the conduction between the cell terminals is not limited to this, and a method of bonding the cell terminals and the conductive material using a conductive adhesive can also be used. As the conductive adhesive, an epoxy adhesive mixed with a conductive material such as silver powder, copper powder, or carbon fiber, a polyimide adhesive, or the like can be used.

  The conductive material 4 is made of a conductive material that can ensure conduction between the cell terminals, and a metal material, conductive plastic, or the like can be used. Examples of the metal material include aluminum, copper, silver, gold, platinum, tungsten, nickel, tin, and zinc. Examples of the conductive plastic include polyacetylene and polythiophene.

  The storage cell body (single cell 1) is covered with an exterior material, and as shown in FIG. 1, the cell terminals (positive tab terminal 2, negative tab terminal 3) are orthogonal to the thickness direction of the storage cell. It protrudes out of the exterior material from the storage cell body. Here, the contact surface of the cell terminal is a surface facing the adjacent cell terminal, and indicates the entire portion protruding from the exterior material. The cell terminal is made of a conductive material, and the entire contact surface has conductivity. The conductive material 4 may be of a size that ensures electrical conduction between the cell terminals and the electrical resistance is sufficiently small. However, the contact area between the contact surface of the cell terminal and the conductive material is the contact surface area of the cell terminal. Is preferably 80% or more, more preferably 90% or more, and even more preferably 100%. The conductive material that contacts the contact surface of the cell terminal may protrude from the cell terminal. However, in order to reduce the size of the conductive material and the storage device module, the conductive material is substantially the same as the contact surface of the cell terminal. It is desirable to have the contact surface. Here, “substantially the same” means that the contact surface area of the conductive material is 95 to 105% of the contact surface area of the cell terminal in consideration of the manufacturing tolerance of the cell terminal and the conductive material and the tolerance at the time of assembly. . Thereby, since almost all of the electrode area of the adjacent cell terminal can be used as the contact area, the electrical resistance at the connection portion is further reduced, and an excellent electrode heat generation suppression and output characteristic improvement effect can be obtained.

  The thickness of the conductive material 4 is substantially equal to the distance between the opposing surfaces of the adjacent cell terminals in a state where the storage cell bodies of the adjacent storage cells are in contact with each other. The thickness of the conductive material is preferably equal to the distance between the opposing surfaces of the cell terminals, but is preferably substantially the same because it is preferably slightly smaller in consideration of workability. When a fixture is used, a gap for arranging the conductive material between the cell terminals is necessary. Moreover, when using an adhesive agent, the clearance gap for an adhesive bond layer is required. The thickness of the conductive material can be 90 to 100%, further 95 to 100% of the distance between the opposing surfaces of the cell terminals.

  The fixture 5 used in the present embodiment is not limited to any material and type as long as it is a member that can be tensioned, such as a binding band. Specifically, a stainless steel band, an insulation lock (insulation fixing) Etc.). Also, a fastening tool such as a bolt can be used. In this case, for example, the flat plates are brought into contact with each other from the outside of one end and the other end of the cell terminal group connected by the conductive material, and the flat plates are fixed by being tightened with bolts. At this time, it is necessary that at least one of the flat plate and the bolt is made of an insulating material, or an insulating material such as a rubber plate is sandwiched between the end cell terminal and the flat plate. When an insulating material is sandwiched between the end cell terminal and the flat plate, a common flat plate can be used for the parallel cell terminal groups. Thus, by applying a load uniformly to the contact surface between the cell terminal and the conductive material with the fixture, it is possible to further ensure conduction between the electrodes of the adjacent cells.

  Further, in the present invention, the electrical resistance between the cell terminals can be further reduced by making the contact surface of the conductive material with the cell terminals into a surface shape that makes line contact or point contact with the cell terminals. . In the case of line contact, the apex angle in the cross section perpendicular to the contact line is preferably an acute angle, more preferably 20 to 70 °. In the case of point contact, the minimum apex angle in a cross section passing through the contact point and orthogonal to the contact surface is preferably an acute angle, more preferably 20 to 70 °. An example thereof is shown in FIGS. 4A to 4C and FIGS. 5A to 5C (units of numerical figures of dimensions in the drawings are mm). A flat copper conductive material 6 (FIGS. 4B and 4C) having a width of 60 mm, a length of 30 mm, and a thickness of 5 mm and an aluminum tab terminal 7 having a width of 60 mm, a length of 26 mm, and a thickness of 0.2 mm are superimposed. In this state (FIG. 4A), when a surface load of 100 N was applied and a current of 2.0 A was applied, the electric resistance was 4.3 mΩ. On the other hand, in the cross section in the width direction, a copper conductive material 8 having a surface shape in which a regular triangular protrusion (vertical angle 60 °) having a base of 5 mm is continuous with the surface and the apex thereof linearly extends in the length direction. (FIGS. 5B and 5C) are overlapped with the same aluminum tab terminal 7 so that they are in line contact with each other (FIG. 5A). The electric resistance was 0.2 mΩ when this current was passed, and the electric resistance could be greatly reduced.

  FIG. 6 is a cross-sectional view of the tab terminal of the electricity storage device module according to the second embodiment of the present invention cut horizontally and viewed from above.

  The power storage device module of the present embodiment uses a lithium ion capacitor as a power storage cell as in the first embodiment. However, as shown in FIG. 6, the positive electrode tab terminals 2 and the negative electrode tab terminals 3 alternate. The conductive material 4 is arranged every other adjacent terminal to be connected in series. Between the terminals where the conductive material 4 is not disposed, an insulating material 9 having the same shape as the conductive material 4 is disposed. As the insulating material 9, a material made of an insulating material such as a resin material such as polyethylene, natural rubber, or earthenware can be used. Since they are connected in series, the fixture 5 is an insulation lock or the like that can be insulated and fixed.

  As described above, the power storage device module of the present invention has a configuration in which a conductive material is contacted between cell terminals to connect the power storage cells, and the module size is not affected by the thickness of the cell, so the size is reduced. Therefore, productivity is high because many processes are not required to connect the storage cells. Further, since the contact area between the cell terminal and the conductive material can be increased, the electrical resistance at the connection portion between the cells is small, so that the electrode heat generation can be suppressed and the output characteristics can be improved.

DESCRIPTION OF SYMBOLS 1 Single cell 2 Positive electrode tab terminal 3 Negative electrode tab terminal 4 Conductive material 5 Fixture 6 Flat plate-shaped conductive material 7 Aluminum tab terminal 8 Conductive material 9 of wire contact surface Insulation material

Claims (5)

  A power storage device module comprising a plurality of power storage cells, wherein the power storage cells are connected to each other by sandwiching a conductive material between cell terminals of the adjacent power storage cells.   The electrical storage device module of Claim 1 which further has a fixing tool for fixing the connection of the said electrical storage cells.   The electric storage device module according to claim 1, wherein a contact surface of the conductive material with the cell terminal has a surface shape that is a line contact or a point contact with the cell terminal.   The power storage device module according to any one of claims 1 to 3, wherein an insulating material is sandwiched between the cell terminals that are not connected to the adjacent power storage cells.   A method of manufacturing a power storage device module including a plurality of power storage cells, wherein the cell terminals of a plurality of power storage cells are aligned and overlapped so that the positions of the cell terminals are aligned, and between the cell terminals of adjacent power storage cells A method comprising: arranging a conductive material; and bringing the cell terminals into contact with the arranged conductive material to connect the storage cells.

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