JP2011151385A - Cylindrical lithium ion capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical lithium ion capacitor capable of comprising a cleavage groove configured to open when the inner pressure of a vessel rises to pressure equal to or higher than predetermined pressure. <P>SOLUTION: A vessel lid to block an opening of a vessel in which an electrode group is accommodated in a hermetically sealed state is configured of a metal lid body 13 and a metal lid cap. The lid body 13 integrally comprises a bulge 13b at the center of a flat plate. The bulge 13b comprises a cylinder and a circular plate 13d the outer circumferential part of which is connected with the other end of the cylinder. The circular plate 13d is divided into two to define a first division region R1 and a second division region R2 by a virtual line L2 perpendicular to a virtual center line L1 passing through the center of the circular plate 13d and extending along the circular plate 13d, and then, a cleavage groove 16 is formed in the first region R1 and a terminal to be electrically connected with one of electrode plates is fixed to the second division region. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cylindrical lithium ion capacitor having a metal lid body provided with a cleavage groove that opens when the internal pressure of a container rises above a predetermined pressure.

  As a large capacity capacitor (for example, 500 F or more), a lithium ion capacitor that combines the advantages of a lithium ion battery and the advantages of an electric double layer capacitor has been developed. In general, lithium ion capacitors being developed recently use activated carbon as a positive electrode active material and a carbon material capable of inserting and extracting lithium ions as a negative electrode active material. In the lithium ion capacitor, the negative electrode potential is kept lower than a normal electric double layer capacitor (approximately 2.2 to 3.8 V) because lithium ions are previously stored or doped in the negative electrode plate (approximately 0 to approximately 3.8 V). 2.5V), can use a wide voltage range (approximately 2.5V width), and as a positive charge / discharge mechanism, in addition to the adsorption of anions used in ordinary electric double layer capacitors, Since adsorption can also be used, the capacity can be doubled in principle. Furthermore, although the lithium ion capacitor has a smaller capacity than the lithium ion battery, it has the advantages of low internal resistance, excellent output characteristics, and long life.

  As a structure of such a lithium ion capacitor, a cylindrical lithium ion capacitor using a wound electrode group is known (Patent Document 1). In a cylindrical lithium ion capacitor, an electrode group is housed inside a bottomed cylindrical metal container. The opening of the container is closed in a sealed state by the container lid. The container lid is configured by combining a metal lid body and a metal lid cap. In such a cylindrical lithium ion capacitor, there is a possibility that the internal pressure of the container will extremely increase due to the gas generated by the decomposition of the electrolytic solution. Therefore, in order to release the gas generated by the decomposition of the electrolytic solution, it is necessary to provide the lid body with a cleavage groove that opens when the internal pressure of the container rises above a predetermined pressure. Such a cleavage groove is an example of a sealed lithium secondary battery, but there is one formed in a container and a container lid (Patent Document 2). In this example, the container lid is configured by combining a metal diaphragm and a metal lid cap. The diaphragm is normally in contact with a connection plate electrically connected to one electrode plate of the electrode group. When the internal pressure of the container rises, the diaphragm is reversed, and the electrical connection between the container lid including the diaphragm and one electrode plate of the electrode group is interrupted. In this sealed lithium secondary battery, cleavage grooves are provided at two locations, the diaphragm and the bottom of the container.

JP 2007-67105 A JP 2006-99977 A

  As described above, some sealed lithium secondary batteries have a cleavage groove. However, a cylindrical lithium ion capacitor has a problem that it is difficult to provide a cleavage groove because the structure of a container lid or the like is different.

  An object of the present invention is to provide a cylindrical lithium ion capacitor having a cleavage groove that opens when the internal pressure of the container rises above a predetermined pressure.

  A cylindrical lithium ion capacitor to be improved by the present invention is a closed-bottomed cylindrical metal container, an electrode group housed inside the container, and an opening of the container housing the electrode group in a sealed state The container lid is closed with The container lid is electrically connected to one electrode plate of the electrode group, and a metal lid main body having a cleavage groove that opens when the internal pressure of the container rises above a predetermined pressure, and the lid main body. And a metal lid cap combined with the lid body so as to form a gap portion communicating with the outside. In the present invention, the lid body is integrally provided with a bulging portion that bulges in the direction away from the lid cap at the center of the disk-shaped flat plate portion. The bulging portion includes a cylindrical portion whose one end is connected to the flat plate portion and a disc portion whose outer peripheral portion is connected to the other end of the cylindrical portion. And when the disk part is divided into two by a virtual line perpendicular to the virtual center line passing through the center of the disk part and extending along the disk part, and defined as the first divided area and the second divided area, A cleavage groove is formed in the first region, and a terminal portion electrically connected to one electrode plate is fixed to the second divided region.

  If the cleavage groove is formed in the first region of the lid body and the terminal portion is fixed to the second divided region as in the present invention, the cleavage groove can be provided in the lid body to which the terminal portion is fixed. Therefore, even in the cylindrical lithium ion capacitor that fixes the terminal portion to the lid body, the cleavage groove can be easily provided in the lid body. Moreover, a space can be secured by providing the bulging portion, and the liquid scattering region becomes narrow due to the buffering effect of the lid cap.

  An annular groove part can be formed in the disk part so as to be concentric with the disk part. In this case, what is necessary is just to arrange | position a cleavage groove and a terminal part in the radial inside of an annular groove part. By appropriately determining the position of such an annular groove portion, it is possible to adjust the deflection of the disc portion and adjust the setting of the internal pressure necessary for the cleavage.

  The cleavage groove can be constituted by an arcuate groove portion concentrically formed with an annular groove portion and one or more linear groove portions extending radially outward from the arcuate groove portion. If the cleavage groove is formed in such a shape, the boundary portion between the arc-shaped groove portion and the linear groove portion has low mechanical strength, so that the cleavage starts from the intersection of the arc-shaped groove portion and the straight groove portion. Can do. Then, the arc-shaped groove portion opens smoothly from the starting point. Therefore, when the internal pressure of the container rises above a predetermined pressure, the cleavage groove can be reliably opened.

  The one or more linear groove portions include first and second linear groove portions that extend radially outward from both ends of the arc-shaped groove portion, and a third linear groove that extends radially outward from the central portion of the arc-shaped groove portion. Can be configured. If it does in this way, three linear groove parts will be distributed and located along an arcuate groove part, and a cleavage groove can be opened reliably in a wider range.

  A position where the first linear groove portion extends from the arc-shaped groove portion is a position away from one end of the arc-shaped groove portion by a predetermined distance toward the central portion of the arc-shaped groove portion, and a position where the second linear groove portion extends from the arc-shaped groove portion. May be a position away from the other end of the arc-shaped groove by a predetermined distance toward the center of the arc-shaped groove. If comprised in this way, the groove part from three directions will cross at the intersection of an arc-shaped groove part and a 1st linear groove part, and the intersection of an arc-shaped groove part and a 2nd linear groove part. Therefore, the mechanical strength at the boundary between the arcuate groove and the linear groove is lower than when the first and second linear grooves extend from both ends of the arcuate groove. For this reason, the intersection is likely to be the starting point of cleavage, and when the internal pressure of the container rises above a predetermined pressure, the cleavage groove can be opened early.

  The distance between the end of the arcuate groove and the first and second linear grooves is arbitrary, but the position where the first linear groove extends from the arcuate groove is adjacent to one end of the arcuate groove. If the position where the second linear groove portion extends from the arc-shaped groove portion is a position adjacent to the other end of the arc-shaped groove portion, the entire arc-shaped groove portion can be reliably opened.

  The terminal portion extends in a direction along the imaginary line and a direction outward in the radial direction and is welded to the disk portion, and an upright portion extending in a direction away from the disk portion from an end portion of the base portion near the imaginary line. It can consist of If it does in this way, a terminal part can be fixed to the 2nd division field of a lid body certainly and easily.

  According to the present invention, the cleavage groove is formed in the first region of the lid body, and the positive terminal portion is fixed in the second divided region. Therefore, the cleavage groove is also reliably provided in the lid body to which the terminal portion is fixed. be able to.

It is a top view of the cylindrical lithium ion capacitor of embodiment which can apply this invention. It is the II-II sectional view taken on the line of FIG. (A) is a top view before winding of the electrode plate of the cylindrical lithium ion capacitor of embodiment, (B) is a top view of the electrical power collector which comprises an electrode plate. It is an expanded sectional view showing typically the lead piece formation part neighborhood of an electrode plate. It is explanatory drawing which shows typically the state before winding an electrode group. It is an external appearance perspective view which shows an electrode group typically. It is the elements on larger scale which typically represent the M section of FIG. It is a top view of the lid main body and positive electrode terminal part before curling process (caulking). It is the IX-IX sectional view taken on the line of FIG. It is the XX sectional view taken on the line of FIG. It is a top view of the other example of a lid body before curling processing (caulking) and a positive electrode terminal part. It is a front view of the lid body provided with the positive electrode terminal part of the cylindrical lithium ion capacitor shown in FIG. It is a rear view of the lid body provided with the positive electrode terminal part of the cylindrical lithium ion capacitor shown in FIG. It is a right view of the lid body provided with the positive electrode terminal part of the cylindrical lithium ion capacitor shown in FIG. It is a left view of the lid body provided with the positive electrode terminal part of the cylindrical lithium ion capacitor shown in FIG. It is a top view of the lid body provided with the positive electrode terminal part of the cylindrical lithium ion capacitor shown in FIG. It is a bottom view of the lid body provided with the positive terminal portion of the cylindrical lithium ion capacitor shown in FIG. It is AA sectional view taken on the line of FIG. It is the BB sectional view taken on the line of FIG.

  Embodiments in which the present invention is applied to a cylindrical lithium ion capacitor will be described below with reference to the drawings.

(Constitution)
<Overall configuration>
As shown in FIGS. 1 and 2 (cross-sectional view taken along the line II-II in FIG. 1), the lithium ion capacitor 30 of the present embodiment (hereinafter abbreviated as capacitor 30) is made of steel plated with nickel. It has a bottomed cylindrical container (can) 8. An electrode group 7 is accommodated in the container 8. As shown in FIG. 5, the electrode group 7 includes a hollow positive electrode plate 2 and a negative electrode plate 3 on a polypropylene shaft core 1 having a hollow cylindrical shape and a plurality of slits (three in this example) formed in the vertical direction. It is configured to be wound through the first separator 4A or the second separator 4B. One metal lithium plate W5 is arranged in the electrode group 7 before doping. The positive electrode plate 2 is composed of two divided positive electrode plates 2A and 2B. As the first and second separators 4A and 4B, a porous substrate such as kraft paper can be used.

<Positive electrode plate>
As described above, the positive electrode plate 2 is composed of two divided positive electrode plates 2A and 2B arranged in the winding direction. The divided positive plates 2A and 2B have the same structure except for the length dimension. As shown in FIGS. 3 and 4, the divided positive plates 2 </ b> A and 2 </ b> B are configured, for example, by coating a positive electrode active material mixture W <b> 2 on both surfaces of an aluminum foil (positive electrode current collector) W <b> 1. As the positive electrode active material mixture W2, for example, a mixture of activated carbon, a binder composed of an acrylic binder, and a dispersant composed of carboxymethyl cellulose (CMC) can be used. The aluminum foil W1 is notched in a comb shape on one side along the longitudinal direction, and a positive electrode lead piece 2a made up of the remaining portion of the notch and a hole in which a number of through holes are formed adjacent to the positive electrode lead piece 2a. And a forming part. Further, the perforated forming part has a through hole non-formed part where a through hole is not formed at a location adjacent to the lead piece forming part along the longitudinal direction. The positive electrode active material mixture W2 described above is applied to the perforated portion with a length that is less than the length in the width direction of the perforated portion.

  Further, the cross section of the end portion on the positive electrode lead piece 2a side of the perforated forming portion coated with the positive electrode active material mixture W2 is in a slurry state before the positive electrode active material mixture W2 is dried, as shown in FIG. Then, it flows to the outermost through hole (closest to the through hole non-formed part) and enters the through hole, so that it is inclined in an obtuse angle (σ) with respect to the coating surface.

<Negative electrode plate>
On the other hand, the negative electrode plate 3 also has substantially the same structure as the positive electrode plate 2 as shown in FIGS. That is, the negative electrode plate 3 has, for example, a negative electrode active material mixture W4 coated on both surfaces of a copper foil (negative electrode current collector) W3. As the negative electrode active material mixture W4, for example, a mixture of amorphous carbon capable of inserting and extracting lithium ions, a binder made of polyvinylidene fluoride (PVDF), and a conductive additive such as acetylene black is used. be able to. The copper foil W3 is notched in a comb shape on one side along the longitudinal direction, and is arranged adjacent to the negative electrode lead piece 3a composed of the remaining portion of the cutout and a large number of through holes. And a perforated forming portion. Further, the perforated forming part has a through hole non-formed part where a through hole is not formed at a location adjacent to the lead piece forming part along the longitudinal direction. The negative electrode active material mixture W4 described above is applied to the perforated forming portion with a length that is less than the length in the width direction of the perforated forming portion.

  Similarly to the positive electrode plate 2, the cross section of the end portion on the negative electrode lead piece 3 a side of the perforated forming part coated with the negative electrode active material mixture W 4 is, as shown in FIG. 4, the negative electrode active material mixture W 4. In the slurry state before drying, it flows to the outermost through hole (closest to the through hole non-formed part) and enters the through hole, thereby inclining in an obtuse angle (σ) with respect to the coating surface. Yes.

<Metal lithium plate>
The total filling amount of the metal lithium plate W5 is set to an amount capable of sufficiently doping lithium ions in the negative electrode active material mixture of the negative electrode plate 3, but the total filling amount takes into consideration the material and amount of the negative electrode active material. Then, the logical calculation can be performed, and the setting can be performed by actually performing doping of lithium ions and confirming whether or not the ions are sufficiently doped. In the present embodiment, the metal lithium plate W5 is arranged on the negative electrode plate 3 as it is in the central region of the electrode group 7 (see FIGS. 5 to 7).

<Electrode group>
As shown in FIGS. 5 to 7, the electrode group 7 includes a first plate having a thickness of 2 so that the positive electrode plate 2 (the divided positive electrode plates 2 </ b> A and 2 </ b> B) and the negative electrode plate 3 are not in direct contact with each other. It is configured to be wound in a cross-sectional spiral shape around the shaft core 1 via the separator 4A or the second separator 4B. The metal lithium plate W5 is disposed on the negative electrode plate 3 so that the wound layer of the metal lithium plate W5 is located in the radial central region of the electrode group 7. Since the metal lithium plate W5 has viscosity when a pressure is applied, the metal lithium plate W5 can be fixed to the negative electrode plate 3 by pressure contact in advance. As shown in FIGS. 5 and 7 (partially enlarged view of M portion in FIG. 6), the divided positive plates 2A and 2B constituting the positive plate 2 are provided on the metallic lithium plate W5 with the first and second separators 4A. , 4B are arranged at predetermined intervals in the winding direction so as to directly overlap each other, and are sequentially inserted and wound between the first and second separators 4A, 4B. By doing in this way, the metal lithium plate W5 does not oppose the positive electrode plate 2 (split positive electrode plates 2A and 2B) via the separators 4A and 4B. The positive electrode lead piece 2a and the negative electrode lead piece 3a described above are arranged on the opposite sides of the electrode group 7, respectively, and protrude a predetermined length from the ends of the separators 4A and 4B. The electrode group 7 is set to a predetermined inner diameter and a predetermined outer diameter by adjusting the lengths of the positive electrode plate 2, the negative electrode plate 3, the separators 4A, 4B, and the like. In addition, the winding termination | terminus part of the electrode group 7 is being fixed by sticking an adhesive tape in order to prevent unwinding.

<Storage structure of electrode group>
As described above, the electrode group 7 is accommodated in the inner peripheral portion of the steel-bottomed cylindrical container 8 plated with nickel. As shown in FIG. 2, a copper negative electrode current collection ring 6 for collecting a potential from the negative electrode plate 3 is provided below the electrode group 7 so as to face the lower end side end face of the electrode group 7. Is arranged. The outer peripheral surface of the lower end portion of the shaft core 1 is fitted to the inner peripheral surface of the negative electrode current collecting ring 6. The tip of the negative electrode lead piece 3a led out from the negative electrode plate 3 is joined to the outer peripheral edge of the negative electrode current collecting ring 6 by ultrasonic welding.

  On the other hand, on the upper side of the electrode group 7, an aluminum positive electrode collector for collecting the electric potentials from the divided positive electrode plates 2 </ b> A and 2 </ b> B substantially on the extension line of the shaft core 1 so as to face the upper end surface of the electrode group 7. An electric ring 5 is arranged. The positive electrode current collecting ring 5 is fitted to the upper end portion of the shaft core 1. The tip of the positive electrode lead piece 2a led out from the divided positive electrode plates 2A and 2B is joined to the peripheral edge integrally protruding from the periphery of the positive electrode current collecting ring 5 by ultrasonic welding.

  A container lid 12 constituting a positive electrode terminal is disposed above the positive electrode current collecting ring 5. The container lid 12 includes a lid main body 13 disposed on the electrode group 7 and a lid cap 14 combined with the lid main body 13. The lid body 13 is made of aluminum, and the lid cap 14 is made of nickel-plated steel like the container 8. The lid cap 14 has an annular flat part 14a and a convex part 14b protruding from the center part of the flat part 14a. The container lid 12 is configured by curling (caulking) the outer peripheral portion of the flat portion 14 a of the lid cap 14 to the edge of the lid body 13. A gap 15 is formed between the convex portion 14 b of the lid cap 14 and the lid body 13. And in the part straddling the convex part 14b and the flat part 14a, the four through-holes 14c which connect the space | gap part 15 of the container lid 12 and the exterior are formed. The four through holes 14c are formed at equal intervals in the circumferential direction of the convex portion 14b.

  The lid body 13 is formed with a cleavage groove 16 (FIG. 8) that opens when the internal pressure of the container 8 rises above a predetermined pressure. The four through holes 14c formed in the lid cap 14 serve to discharge the gas inside the container to the outside when the cleavage groove 16 of the lid body 13 is opened. One end of one positive terminal portion 10A out of two positive terminal portions laminated with ribbon-like aluminum foil is joined to the upper surface of the positive current collecting ring 5. Another positive terminal portion 10B of the positive terminal portion is welded to the outer bottom surface of the lid main body 13 constituting the container lid 12. The other ends of the two positive terminal portions 10A and 10B are also joined. Thereby, the lid body 13 is electrically connected to one electrode plate (positive electrode plate) of the electrode group 7. The lid body 13, the cleavage groove 16, and the positive terminal portion 10B will be described in detail later.

  The container lid 12 is inserted into the opening of the container 8 that has been drawn and has an annular stepped portion 8b formed in the vicinity of the opening, and is disposed on the stepped portion 8b. The open end 8a of the container 8 is curled (caulked) so as to approach the container lid 12 via a gasket 17 made of a rubber-based material made of an electrically insulating material having moisture permeability and heat resistance. . As a result, the container lid 12 is fixed between the open end 8a and the step 8b that are curled, with the gasket 17 interposed therebetween. Thereby, the inside of the capacitor 30 is sealed.

  And the exposed part 17a of the gasket 17 exposed from between the opening end part 8a of the container 8 and the container lid 12, and the boundary part 18 formed between the exposed part 17a of the gasket 17 and the opening end part 8a of the container 8. A boundary 19 formed between the exposed portion 17 a of the gasket 17 and the container lid 12 is covered with a waterproof seal portion 21. The waterproof seal portion 21 is formed using a waterproof seal material made of epoxy resin, perfluoroelastomer, or the like. The waterproof seal portion 21 is formed so as not to block the through hole 14c.

A nonaqueous electrolyte solution (not shown) in an amount capable of infiltrating the entire electrode group 7 is injected into the container 8. Examples of the non-aqueous electrolyte include phosphorus hexafluoride as a lithium salt in a solvent in which ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) are mixed at a volume ratio of 30:50:20. A solution in which lithium acid (LiPF ₆ ) is dissolved can be used.

<Structure of lid body and cleavage groove>
As shown in FIGS. 8 and 9, the lid body 13 is integrally provided with a bulging portion 13 b that bulges in the direction away from the lid cap 14 at the center of the disc-shaped flat plate portion 13 a. 8 is a plan view of the lid main body 13 before curling (caulking) to which the positive electrode terminal portion 10B is fixed, and FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. The cylindrical portion 13g rising from the edge of the flat plate portion 13a is subjected to curling (caulking) in the capacitor manufacturing process.

  The bulging portion 13b includes a cylindrical portion 13c having one end connected to the flat plate portion 13a and a disc portion 13d having an outer peripheral portion connected to the other end of the cylindrical portion 13c. A projecting portion 13e that protrudes toward the lid cap 14 is formed concentrically with the disc portion 13d in the disc portion 13d. As a result of forming the protruding portion 13e, an annular groove portion 13f is formed on the opposite side of the protruding portion 13e in the disc portion 13d so as to be concentric with the disc portion 13d. The disk portion 13d is divided into two parts by a virtual line L2 that is perpendicular to the virtual center line L1 passing through the center of the disk portion 13d and extends along the disk portion 13d. R1 and a second divided region R2. A cleavage groove 16 is formed on the radially inner side of the annular projecting portion 13e (annular groove portion 13f) of the first region R1, and the annular projecting portion 13e (circular shape of the second divided region R2). A positive electrode terminal portion 10B that is electrically connected to one of the electrode plates (positive electrode plate 2) is fixed on the radially inner side of the annular groove portion 13f). The positive electrode terminal portion 10B extends in a direction along the imaginary line L2 and a direction outward in the radial direction and is welded to the disc portion 13d, and the disc portion 13d from the end portion of the base portion 10c near the imaginary line L2. 10d extending in the direction away from the head.

  As shown in FIGS. 8 and 10 (cross-sectional view taken along line XX in FIG. 8), the cleavage groove 16 formed in the first divided region R1 extends toward the lid cap 14 at a predetermined angle θ. It is open and has a flat bottom surface 16e. The cleavage groove 16 includes an arcuate groove portion 16a and first to third linear groove portions 16b to 16d. The arcuate groove 16a is formed concentrically with the annular groove 13f. The 1st and 2nd linear groove parts 16b and 16c are extended in the diameter direction outside of groove part 13f from the both ends of arcuate groove part 16a. The third linear groove portion 16d extends outward in the radial direction of the groove portion 13f from the central portion of the arc-shaped groove portion 16a.

  In the cylindrical lithium ion capacitor of this example, when the internal pressure of the container 8 rises to a predetermined pressure (1.8 MPa in this example) or higher, the intersection 16f to 16h of the arcuate groove 16a and the linear grooves 16b to 16d starts. Then, the cleavage starts, and the entire arcuate groove 16a and linear grooves 16b to 16d are opened. Thereby, the gas generated by the decomposition of the electrolytic solution is released.

  FIG. 11 is a plan view of another example of the lid main body 13 before the curling process (caulking) to which the positive electrode terminal portion 10B is fixed. In the cleavage groove 16 shown in FIG. 11, the first linear groove portion 16b extends from one end of the arc-shaped groove portion 16a from a position away from the central portion of the arc-shaped groove portion 16a by a predetermined distance, and the second linear groove portion. 16c extends from the other end of the arcuate groove 16a from a position away from the other end of the arcuate groove 16a to the center of the arcuate groove 16a. Specifically, the first linear groove portion 16b extends from a portion adjacent to one end of the arc-shaped groove portion 16a, and the second linear groove portion 16c extends from a portion adjacent to the other end of the arc-shaped groove portion 16a. Yes. Grooves from three directions intersect at the intersection 16f between the arc-shaped groove and the first linear groove and the intersection 16g between the arc-shaped and second linear groove in FIG. Therefore, the mechanical strength at the boundary between the arcuate groove 16a and the linear groove 16b or 16g is lower than in the case of FIG. 8 in which the first and second linear grooves extend from both ends of the arcuate groove. Thus, the intersection is likely to be the starting point of the cleavage, and the cleavage groove 16 can be opened early when the internal pressure of the container rises above a predetermined pressure. In FIG. 11, in particular, the position where the first linear groove 16b extends from the arc-shaped groove 16a is a position adjacent to one end of the arc-shaped groove 16a, and the position where the second linear groove 16c extends from the arc-shaped groove 16a. It is a position adjacent to the other end of the arcuate groove 16a. Therefore, the entire arc-shaped groove can be reliably cleaved, and the gas generated by the decomposition of the electrolytic solution can be released.

  In the present embodiment, three linear grooves are provided, but only one central linear groove 16d may be provided, or only two linear grooves 16b and 16c at both ends are provided. You may make it provide. Further, the shape of the cleavage groove 16 is not limited to the shape of the present embodiment, and a cleavage groove of another shape may be used.

  12 to 19 are a front view, a rear view, a right side view, a left side view, a plan view, a bottom view, and a cross-sectional view taken along the line AA in FIG. 12 of the lid main body 13 including the positive electrode terminal portion 10B. FIG. 18 is a cross-sectional view taken along line BB in FIG.

(Function)
According to the present embodiment, the cleavage groove 16 is formed in the first region R1 of the lid main body 13, and the positive terminal portion 10B is fixed to the second divided region R2, so that the positive terminal portion 10B is fixed. The body 13 can be provided with a cleavage groove 16. Therefore, also in the cylindrical lithium ion capacitor that fixes the positive electrode terminal portion 10 </ b> B to the lid main body 13, the cleavage groove 16 can be easily provided in the lid main body 13.

7 Electrode group 8 Container (can)
10A, 10B Positive electrode terminal portion 10c Base portion 10d Standing portion 12 Container lid 13 Lid body 13d Disk portion 13e Projection portion 13f Groove portion 13g Tube portion 14 Lid cap 16 Cleavage groove 16a Arc-shaped groove portions 16b to 16d First to third straight lines Groove L1 Virtual center line L2 Virtual line R1 First divided region R2 Second divided region

Claims (7)

A bottomed cylindrical metal container;
A group of electrodes housed inside the container;
A container lid for sealingly closing the opening of the container in which the electrode group is stored;
The container lid is electrically connected to one electrode plate of the electrode group, and a metal lid body provided with a cleavage groove that opens when the internal pressure of the container rises above a predetermined pressure; and the lid body A cylindrical lithium ion capacitor composed of a metal lid cap combined with the lid body so as to form a gap portion communicating with the outside between,
The lid body is integrally provided with a bulging portion that bulges in the direction away from the lid cap at the center of a disk-shaped flat plate portion,
The bulging portion includes a cylindrical portion having one end connected to the flat plate portion and a disc portion having an outer peripheral portion connected to the other end of the cylindrical portion,
When the disc portion is divided into two by a virtual line that is orthogonal to a virtual center line passing through the center of the disc portion and extends along the disc portion, and is defined as a first divided region and a second divided region A cylindrical lithium ion capacitor, wherein the cleavage groove is formed in the first region, and a terminal portion electrically connected to the one electrode plate is fixed to the second divided region. . An annular groove is formed in the disk part so as to be concentric with the disk part,
2. The cylindrical lithium ion capacitor according to claim 1, wherein the cleavage groove and the terminal portion are disposed radially inward of the annular groove portion.   The cylinder according to claim 1 or 2, wherein the cleavage groove includes an arcuate groove part concentrically formed with the annular groove part and one or more linear groove parts extending radially outward from the arcuate groove part. Lithium ion capacitor.   The one or more linear groove portions include first and second linear groove portions that extend radially outward from both ends of the arc-shaped groove portion, and a third portion that extends radially outward from a central portion of the arc-shaped groove portion. The cylindrical lithium ion capacitor according to claim 3, comprising a linear groove portion.   The one or more linear groove portions include a first linear groove portion extending outward in the radial direction from a position separated from one end of the arc-shaped groove portion by a predetermined distance toward a central portion of the arc-shaped groove portion, and the arc-shaped groove portion. A second linear groove portion extending outward in the radial direction from a position spaced a predetermined distance from the other end to the central portion side of the arc-shaped groove portion, and a third extending outward in the radial direction from the central portion of the arc-shaped groove portion. The cylindrical lithium ion capacitor according to claim 3, comprising:   The first linear groove portion extends radially outward from a portion adjacent to one end of the arcuate groove portion, and the second linear groove portion extends from a portion adjacent to the other end of the arcuate groove portion. The cylindrical lithium ion capacitor according to claim 5, which extends outward in the radial direction.   The terminal portion extends in a direction along the imaginary line and a direction outward in the radial direction and is welded to the disc portion, and a direction away from the disc portion from an end portion of the base portion near the imaginary line The cylindrical lithium ion capacitor according to claim 1, wherein the cylindrical lithium ion capacitor comprises an upright portion extending in a vertical direction.

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