JP2009088033A - Electrical double-layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrical double-layer capacitor which is firstly excellent in connection between collector leads and between the collector lead and an external electrode terminal and which reduces secondly a mechanical stress to an electrode sheet caused by the collector lead even if the number of electrode sheets is increased. <P>SOLUTION: An electrical double-layer capacitor includes a plurality of positive and negative electrode sheets each comprising a polarizable electrode layer on a collector front surface, a separator inserted between the electrode sheets when the positive electrode sheet and the negative electrode sheet are alternately laminated, a plurality of collector leads extended from the collectors provided on the electrode sheets, a drawing lead which connects the collector leads for each pole and which is connected to each connection portion, a plurality of elements formed in such a manner that they connect the drawing lead, a sealing plate for sealing an exterior case in which the element is inserted, and an external electrode terminal provided on the sealing plate. The external electrode terminal is connected with the drawing lead. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric double layer capacitor, and in particular, even when the number of electrode sheets increases, the connection between current collecting leads and between current collecting leads and external electrode terminals is good, and mechanical stress on the electrode sheet due to the current collecting leads is reduced. The present invention relates to an electric double layer capacitor.

  Patent Document 1 discloses a multi-layered structure in which a plurality of electrode sheets each having a polarizable electrode layer on a current collector surface are stacked via a separator as an electric double layer capacitor, and are extended from each current collector. The current collecting leads are grouped for each pole and connected to external electrode terminals of each pole.

  Further, in Patent Document 2, electrode sheets are arranged in parallel on both ends of the current collecting leads, and this is laminated, and the current collecting lead portion is joined and connected to the external electrode terminal, thereby halving the increase in the number of current collecting leads. Yes.

JP-A-4-154106 JP 2000-82641 A

  However, in such an electric double layer capacitor, when the capacitor capacity is increased by increasing the number of electrode sheets, the number of current collecting leads also increases.

  Here, when the current collecting leads increase and the total thickness of the lead connecting portion becomes 2 mm or more, first, the connection state by welding is poor between the current collecting leads and between the current collecting leads and the external electrode terminals. Continuity becomes incomplete (increase in internal resistance). Secondly, since the thickness of the element increases, the distance from each electrode sheet to the current collector lead connection varies, and the current collector lead can be slackened or excessively tensioned. There has been a problem that a stress is applied or a stacking position shift occurs, causing a decrease in capacity or a short circuit failure.

  Patent document 2 is proposed as what improved this. However, even in this case, due to further increase in the electrode sheet, firstly, between the current collecting lead parts, and between the current collecting lead and the external electrode terminal, the connection state is deteriorated, and secondly, the current collecting lead is slack, There has been insufficient solution to the problem that mechanical stress on the electrode sheets and displacement between the electrode sheets occur due to excessive tension, causing a decrease in capacity and a short circuit failure.

  Therefore, in the present application, even if the number of electrode sheets increases, firstly, the connection between the current collecting leads and between the current collecting leads and the external electrode terminal is good, and second, the machine to the electrode sheet by the current collecting leads. An object of the present invention is to provide an electric double layer capacitor with reduced mechanical stress.

  In order to solve the above problems, an electric double layer capacitor according to the first aspect of the present invention includes a plurality of positive and negative electrode sheets each having a polarizable electrode layer on a current collector surface, and the positive electrode sheet And separators inserted between the electrode sheets when the electrode sheets and the negative electrode sheets are alternately laminated, a plurality of current collecting leads extended from the current collectors provided in the electrode sheets, and the current collectors A lead connected to each connecting portion by connecting electrical leads for each same pole, a plurality of elements formed by connecting the lead leads, a sealing plate for sealing an exterior case into which the element is inserted, An external electrode terminal provided on the sealing plate, and the external electrode terminal and the extraction lead are connected.

  The electric double layer capacitor according to the second aspect of the present invention comprises a plurality of positive and negative electrode sheets each having a polarizable electrode layer on a current collector surface, and the positive electrode sheet and the negative electrode sheet alternately Separators inserted between the electrode sheets when stacked on each other, a plurality of current collecting leads extended from the current collectors provided on the electrode sheets, and the current collecting leads connected to the same polarity A lead connected to each connecting portion, and an element formed by connecting the lead, and the element is arranged so as to be symmetrical with respect to an external electrode terminal, The elements are integrated by connecting the lead leads to the external electrode terminals of the respective poles.

  In addition, only a part of the lead leads of all the elements are connected to the external electrode terminals, and the other lead leads may be connected at a portion other than the connecting part of the part of the lead leads and the external electrode terminal. Good.

  Furthermore, the thickness of the connected current collecting lead or the lead lead is within 2 mm.

  By adopting the electric double layer capacitor according to the present invention, even if the number of electrode sheets is increased, there is an effect that the connection between the current collecting leads and between the current collecting lead and the external electrode terminal is improved first. .

  Second, it has the effect of reducing mechanical stress on the electrode sheet due to the current collecting leads.

(Function)
Since the number of current collecting leads for each element can be kept below a certain number, the connection between the current collecting leads and between the current collecting lead and the lead out can be kept in good condition, and the thickness of the element Since the distance from each electrode sheet to the collector lead joint is small, there is no stress on the electrode sheet due to the collector lead, and the capacity is reduced due to short circuit failure or misalignment between the electrode sheets. Etc. are also resolved.

  In addition, when the lead is connected to the external electrode terminal in a state where the element is arranged to be the target with respect to the external electrode terminal, the length of the lead can be shortened. Stress can be further reduced.

  Hereinafter, an embodiment of the present invention will be described in detail.

  The electric double layer capacitor according to the present invention includes a plurality of positive and negative electrode sheets 7 each having a polarizable electrode layer 5 on the surface of the current collector 3, and the positive electrode sheet and the negative electrode sheet 7 alternately. The separator inserted between the electrode sheets 7 when stacked, the plurality of current collecting leads 4 extending from the current collectors 3 provided in the electrode sheet 7, and the current collecting leads 4 are the same. The lead 6 connected for each pole and connected to each connecting portion, the element 2 formed by connecting the lead 6 and a case (not shown) for inserting the element 2 are sealed. The sealing plate 8, the external electrode terminal 10 provided on the sealing plate 8, and the external electrode terminal and the lead lead are connected.

Example 1
A first embodiment of an electronic double layer capacitor according to the present invention will be described with reference to FIGS.

  1A shows the electrode sheet 7 in FIG. 1A and FIG. 1B shows the configuration of the element 2.

  The electrode sheet 7 is provided with a current collector 3 in the center, and a current collecting lead 4 is projected from an end of one side of the electrode sheet 7 on the external electrode terminal side. In addition, polarizable electrode layers 5 are laminated on both surfaces of the current collector 3. Here, the positive electrode sheet 7 and the negative electrode sheet 7 protrude so as not to overlap when the protruding positions of the current collecting leads 4 are stacked.

  The configuration of the element 2 is shown in FIG. In the element 2, a separator is stacked on a positive electrical sheet, and a negative electrode sheet is further disposed on the separator. A separator is further laminated on the negative electrode sheet, and a positive electrode sheet is laminated again.

  On the other hand, the current collecting lead 4 is configured such that when a plurality of electrode sheets are stacked, the current collecting leads 4 of the same polarity do not overlap with each other.

  The lead leads 6 are electrically connected by bundling the current collecting leads 4 for each pole, and one lead lead 6 is provided for each pole.

  FIG. 2 (a) shows a side view and FIG. 2 (b) shows a top view of the method of coupling the lead 6 and the external electrode terminal 10 in the electric double layer capacitor according to the present invention.

  In the electric double layer capacitor according to the first embodiment of the present invention, the same number of lead leads 6 as the elements 2 are provided, and the end portions of all the lead leads 6 are coupled to the end portions of the external electrode terminals 10. This external electrode terminal is also provided with a positive electrode and a negative electrode penetrating through the sealing plate at a certain interval. All the extraction leads of the positive electrode are fixed to the lower end portion in the vertical direction at the external electrode terminal of the positive electrode, and all the extraction leads of the negative electrode are fixed to the lower end portion in the vertical direction at the external electrode terminal of the negative electrode. Here, the element 2 is disposed in parallel with the sealing plate 8, and thus the external through terminal 10 and the element 2 are disposed vertically. Furthermore, the element 2 is arranged only in one direction with respect to two external electrode terminals 10 with respect to a virtual “straight line” (not shown) connecting the external electrode terminals.

(Example 2)
FIG. 3 shows a side view of a method of coupling the lead 6 and the external electrode terminal 10 in the electric double layer capacitor according to the second embodiment of the present invention.

  In the second embodiment, only one point of the lead 9 of the element located closest to the sealing plate 8 is fixed to the lower end portion in the vertical direction at the external electrode terminal. The lead leads 11 and 12 of other elements are coupled to each other at an intermediate point 13 of the lead lead 9. For this reason, the number of lead leads connected to the external electrode terminals can be reduced. For this reason, even when the number of elements is increased, the thickness of the lead coupling portion in the external electrode terminal is not increased. For this reason, it becomes possible to reduce the increase in internal resistance due to the deterioration of the connection state by welding. In addition, it is possible to reduce the variation in the distance from each electrode sheet to the connecting part of the current collector lead, to prevent the current collector lead from loosening and excessive tension, and to prevent mechanical stress from being applied to the electrode sheet. Thus, it is possible to prevent a decrease in capacity and a short circuit failure due to misalignment of the electrode sheets.

(Example 3)
FIG. 4A shows a side view and FIG. 4B shows a top view of the method of coupling the lead 16 and the external electrode terminal 24 in the electric double layer capacitor of Example 3 according to the present invention.

  The difference from the electric double layer capacitor of Example 1 according to the present invention is that Example 2 is a virtual “straight line” (not shown) connecting the external electrode terminals of the element 2 with respect to the two external electrode terminals 24. In contrast to being arranged only in one direction, the third embodiment has elements 20 arranged on both sides with respect to a virtual “straight line” (not shown) connecting the external electrode terminals. (FIG. 4B). Since the element 20 is disposed on both sides with respect to the “straight line”, the capacitance can be increased by a factor of two with the same thickness. However, since all the lead leads of each electrode are coupled to the lower end of the external electrode terminal, the thickness of the lead lead at the lower end of the external electrode terminal is the sum of the thicknesses of all the lead leads of each electrode (FIG. 4). (Center of (a)).

Example 4
FIG. 5 shows a side view of a method for coupling the lead lead 36 and the external electrode terminal 30 in the electric double layer capacitor according to the fourth embodiment of the present invention.

  The difference between the electric double layer capacitor of the second embodiment according to the present invention is that, in the second embodiment, the element 2 is a virtual “straight line” (not shown) connecting the external electrode terminals 10 with respect to the two external electrode terminals 10. In Example 4, the elements 26 are arranged on both sides with respect to a virtual “straight line” (not shown) connecting the external electrode terminals. Is a point. Since the element 26 is arranged on both sides with respect to the “straight line”, the capacitance can be increased by a factor of two with the same thickness.

  Furthermore, in Example 4, only one point of the lead lead 36 of the element located closest to the sealing plate 22 is fixed to the lower end portion in the vertical direction at the external electrode terminal. The lead leads 32, 34 of the other elements are coupled to each other at an intermediate point 38 of the lead lead 36. For this reason, the number of lead leads connected to the external electrode terminals can be reduced. For this reason, even when the number of elements is increased, the thickness of the lead coupling portion in the external electrode terminal is not increased. For this reason, it becomes possible to reduce the increase in internal resistance due to the deterioration of the connection state by welding. In addition, it is possible to reduce the variation in the distance from each electrode sheet to the connecting part of the current collector lead, to prevent the current collector lead from loosening and excessive tension, and to prevent mechanical stress from being applied to the electrode sheet. Thus, it is possible to prevent a decrease in capacity and a short circuit failure due to misalignment of the electrode sheets.

It is the (a) block diagram of the electrode sheet in Example 1 of the electronic double layer capacitor based on this invention, (b) The block diagram of an element. It is (a) side view and (b) top view about the coupling | bonding method of the lead | read | reed lead | read | reed and external electrode terminal in Example 2 of the electronic double layer capacitor based on this invention. It is a side view about the coupling | bonding method of the extraction lead | read | reed and external electrode terminal in Example 3 of the electronic double layer capacitor which concerns on this invention. It is the (a) side view and (b) top view about the coupling | bonding method of the extraction lead | read | reed and external electrode terminal in Example 4 of the electronic double layer capacitor based on this invention. It is a side view about the coupling | bonding method of the extraction lead | read | reed and external electrode terminal in Example 5 of the electronic double layer capacitor which concerns on this invention.

Explanation of symbols

2 Element 3 Current collector 4 Current collecting lead 5 Polarized electrode layer 6 Leading lead 7 Electrode sheet 8 Sealing plate 9 Leading lead 10 External electrode terminals 11 and 12 Leading lead 13 Intermediate point 16 of leading lead 9 Leading lead 20 Element 22 Sealing Plate 24 External electrode terminal 26 Element 30 External electrode terminals 32 and 34 Lead lead 36 Lead lead 38 Intermediate point of lead lead 36

Claims (4)

  A plurality of positive and negative electrode sheets each having a polarizable electrode layer on the current collector surface, and the positive electrode sheet and the negative electrode sheet are inserted between the electrode sheets when alternately stacked. A separator, a plurality of current collecting leads extending from each of the current collectors provided in the electrode sheet, a lead for connecting the current collecting leads for each of the same poles, and connecting to each connecting portion; and the drawer A plurality of elements formed by connecting leads, a sealing plate for sealing an exterior case into which the elements are inserted, an external electrode terminal provided on the sealing plate, and the external electrode terminal and the lead lead are connected. An electric double layer capacitor characterized by being made. A plurality of positive and negative electrode sheets each having a polarizable electrode layer on the current collector surface, and the positive electrode sheet and the negative electrode sheet are inserted between the electrode sheets when alternately stacked. A separator, a plurality of current collecting leads extending from each of the current collectors provided in the electrode sheet, a lead for connecting the current collecting leads for each of the same poles and connecting to each connecting portion; and the drawer It has an element formed by connecting leads,
The element is arranged to be line-symmetric with respect to the external electrode terminal,
An electric double layer capacitor in which elements are integrated by connecting the lead lead of each electrode to an external electrode terminal of each electrode.   In the lead lead, only a part of the lead leads of all elements are connected to the external electrode terminal, and the other lead leads are coupled at a portion other than the coupling portion of the part of the lead lead and the external electrode terminal. The electric double layer capacitor according to claim 1 or 2.   3. The electric double layer capacitor according to claim 1, wherein the connected current collecting lead or the lead lead has a thickness of 2 mm or less.

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