JP4206352B2 - Degassing valve and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently realize a gas releasing valve which will not generate deformation which will interfere with normal valve functions with the heat generated, when a capacitor body formed of a positive electrode, a negative electrode, and a separator, is thermally fused to a vessel for sealing thereof together with the electrolyte. <P>SOLUTION: The gas release valve is provided with a thermoplastic resin valve body 21 forming a gas-releasing path 23, and a thermosetting resin ring body 22 which is included within the valve body 21, to guide the motion of a valve body 30. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a degassing valve provided for maintaining the performance (characteristics) of an electric double layer capacitor for a long time and a method for manufacturing the same.

  2. Description of the Related Art In recent years, as various types of power storage devices, attention has been focused on application technologies of electric double layer capacitors that can be rapidly charged and have a long charge / discharge cycle life.

  The electric double layer capacitor is composed of a winding type in which a strip-like positive electrode body and a negative electrode body are rolled into a roll with a separator interposed therebetween, and a flat plate positive electrode body and a negative electrode body interposed between them. However, it is broadly classified into a laminated type in which the layers are alternately stacked.

  7 and 8, an example of the laminated type will be described. Reference numeral 10 denotes a container for sealing the laminated body 15 (capacitor main body) together with the electrolytic solution, and 11 denotes a pair of terminal boards (a part of which is drawn out of the container 10). Each terminal plate 11 is made of aluminum having a light weight and a small electrical resistance in a short shape.

  The capacitor body 15 is composed into a predetermined laminate by alternately stacking a positive electrode body (positive electrode body) and a negative electrode body (negative electrode body) with a separator interposed therebetween. A positive electrode body and a negative electrode body are comprised in flat form from the collector electrode and the polarizable electrode (activated carbon electrode) formed in the both surfaces. These collector electrodes are made of a rectangular metal foil (aluminum foil), and a strip-like conductive portion (lead) is integrally formed on one side of a rectangular plane. The conductive parts have the same polarity and the converging part having the corresponding polarity is joined to the pair of terminal plates 11.

  The container 10 is composed of two container members (a bottom side member and a lid side member) formed by cold pressing from a flexible laminated film (for example, aluminum laminate) including a metal intermediate layer in a plurality of resin layers. When these are combined, the accommodating part of the laminated body 15 is formed between the bottom side member and the lid side member by the concave portions facing each other.

  The capacitor main body 15 is housed inside the bottom side member, and the lid side member is placed thereon. At the peripheral edge of the container 10, three sides excluding one side from which the pair of terminal plates 11 (part thereof) are drawn are heat welded (heat sealed). The container 10 can be opened at one side from which the pair of terminal plates 11 protrudes. After the electrolytic solution is injected from the opening and the impregnation treatment of the electrolytic solution is finished, the vacuum pump removes air and moisture. The remaining one side is heat welded (heat sealed).

In such an electric double layer capacitor, when the remaining moisture and functional groups of the activated carbon electrode are electrolyzed due to repeated charging and discharging, and gas (CO, CO _2, etc.) is generated, the internal pressure of the container 10 gradually increases, and the capacitor The performance may be hindered. For this reason, a gas vent valve 12 for removing the gas generated inside the container 10 to the outside of the container 10 is provided. In the case of illustration, the gas vent valve 12 is assembled | attached by the heat welding which seals the opening part to the upper part of the container 10 which a pair of terminal board 11 protrudes.

In Patent Document 1 and Patent Document 2, in order to improve the airtightness of a container (pouch with a cap) for stuffing beverages or the like, a device in which the cap is thermally welded to a bag formed of a laminated material having a three-layer structure is disclosed. The
JP 2001-328649 A JP 2003-19970 A

  The degassing valve 12 is set to have a configuration in which the valve element is separated from the valve seat and opens the degassing passage when the pressure generated by the gas generated in the container 10 that encloses the capacitor body 15 together with the electrolyte is increased to a predetermined value. . The valve body forming the gas vent passage and the valve seat is made of a thermoplastic resin, and can be easily and easily assembled together with the pair of terminal plates 11 by thermal welding for sealing the container 10. However, there is a possibility that the inside of the valve body will be deformed by heating during heat welding. If the inside of the valve body is deformed, the operation of the valve body is hindered, and a normal degassing function (valve function) is also obtained. There is a problem that it cannot be performed.

  The present invention provides a degassing valve and a rational manufacturing method thereof that can be assembled easily and easily by heat welding and that does not cause deformation that would hinder normal valve function even by heating. Objective.

  According to a first aspect of the present invention, when the internal pressure of a predetermined value or more is generated by a gas generated in a container enclosing a capacitor body composed of a positive electrode body, a negative electrode body, and a separator together with an electrolytic solution, the valve body separates from the valve seat and gas In the gas vent valve for letting out the air, it is provided with a thermoplastic resin valve body that forms a gas vent passage, and a thermosetting resin ring body that is contained in the valve body and guides the movement of the valve body. It is characterized by.

  According to a second aspect of the present invention, in the degassing valve according to the first aspect, the ring body is formed of a thermosetting resin having resistance to an electrolytic solution.

  According to a third aspect of the present invention, in the degassing valve according to the first aspect, the ring body made of a thermosetting resin integrally forms a valve seat.

  According to a fourth aspect of the present invention, when the internal pressure of a predetermined value or more is generated by a gas generated in a container enclosing a capacitor body composed of a positive electrode body, a negative electrode body, and a separator together with an electrolyte, the valve body separates from the valve seat and gas In the method of manufacturing the gas vent valve for letting out the outside, a ring body formed in advance from a thermosetting resin is fitted to one of two cores that can advance and retreat on the same axis, and the other core is fitted to the tip thereof. While the tip is abutted on the same axis and the mold is tightened in this state, the mold is filled with a thermoplastic resin that has been given fluidity by heating. On the other hand, after cooling and solidification, the two cores are placed in opposite directions from the mold. And a step of creating a valve body containing the ring body by opening the mold and projecting the molded product by opening the mold.

  According to the first invention, the gas vent valve is easily and easily assembled by heat welding (heat seal) through the valve body made of a thermoplastic resin together with the sealing of the container. Since the ring body included in the valve body is made of a thermosetting resin, the movement of the valve body can be normally guided without being deformed by heating during heat welding.

  According to the second invention, even when the electrolyte is taken out from the inside of the container together with the gas and adheres to the ring body, the ring body is a thermosetting resin having electrolyte solution resistance. The function (guides the movement of the valve body) is not harmed by corrosion or the like.

  According to the third invention, since the ring body is integrally formed from the thermosetting resin including the valve seat, it is possible to ensure a normal operation of the valve body and a high degree of sealing performance when the valve is closed.

  According to the fourth aspect of the present invention, it is possible to rationally manufacture a vent valve that is easily and easily assembled by heat welding and that does not cause deformation that hinders normal valve function even by heating at that time. In the process of creating a valve body that encloses the ring body, a preformed ring body is molded from a thermoplastic resin (valve body) by a simple method using one of two cores that can advance and retreat on the same axis. ). The two cores are extracted from the mold after cooling and solidification to form a gas vent passage inside the molded product.

  1 to 3 show a gas vent valve 20 assembled in a container of an electric double layer capacitor, and includes a ring body 22 included in a valve body 21. The valve body 21 includes a heat welding portion 24 with the container 10 (see FIGS. 7 and 8), an insertion portion 25 into the inside of the container 10, and a protruding portion 26 to the outside of the container 10. A degassing passage 23 penetrating through is formed.

  The gas vent passage 23 is formed as a small diameter passage 23a on the insertion portion 25 (inlet) side and a large diameter passage 23b on the protruding portion 26 (outlet) side, and is provided at the boundary (step surface) between the small diameter passage 23a and the large diameter passage 23b. A seat 23c (valve seat) is set. A valve body 30 (valve rubber) connects and closes (opens and closes) the valve seat 23c, and its tip is formed in a conical shape that can be inserted into the small diameter passage 23a.

  The large diameter passage 23 b is closed by the cap 29, and a plurality of through holes (not shown) are formed in the valve body 21 and the cap 29 in order to secure the outlet of the gas vent passage 23. The valve body 30 is provided with a shaft portion 31 extending in the center toward the cap side, and when the tip of the shaft portion 31 approaching the cap 29 comes into contact with the cap 29 as the valve body 30 moves away from the valve seat 23c, that of the valve body 30 is provided. The above movement is restricted.

  A spring 32 sets the valve opening pressure of the valve body 30 and is interposed between the cap 29 and the spring receiver 33. The spring receiver 33 is formed in a piston shape that partitions the large-diameter passage 23b, and the shaft portion 31 of the valve body 30 passes through the center thereof. The ring body 22 guides the movement of the valve body 30 in the movable range of the valve body 30 restricted by the shaft portion 31, and forms a sliding contact surface with the spring receiver 33. A through hole that forms a part of the gas vent passage 23 is set between the spring receiver 33 and the ring body 22.

  The valve body 21 is made of a thermoplastic resin (for example, polypropylene) that is easily heat-welded (see FIG. 2). In order to secure a large heat welding surface with the container 10, the heat welding portion 24 of the valve body 21 is expanded in a wing shape. The ring body 22 is made of a thermosetting resin (for example, phenol resin) that is excellent in electrolytic solution resistance and hardly deforms into heat (see FIG. 3). In the process of creating the valve body 21 described later, a ring body 22 formed in advance is included in the valve body 21. The cap 29 is formed separately from the valve body 21, and is attached to the valve body 21 after the spring 32 is housed in the large diameter passage 23 b together with the valve body 30 and the spring receiver 33.

  The gas vent valve 20 is assembled to the upper part of the container 10 from which the pair of terminal plates 11 protrudes by heat welding as in the past (see FIGS. 7 and 8). Since the ring body 22 included in the valve body 21 is made of a thermosetting resin, deformation due to heating during heat welding does not occur, and the movement of the valve body 30 can be guided normally.

  If the pressure generated by the gas generated inside the container 10 with repeated charging / discharging becomes a predetermined value or more, the valve body 30 is separated from the valve seat 23c while compressing the spring 32, and the gas vent passage 23 is opened. Gas is discharged from the inside of the container 10 to the outside. Therefore, the inside of the container 10 is suppressed to a pressure less than a predetermined value by the gas vent valve 20, and good capacitor performance (characteristics) can be maintained for a long time.

  FIG. 4 illustrates a process of creating the valve body 21 and includes an inner ring and core setting process, a thermoplastic resin filling process, and a mold removing process. Reference numeral 40 denotes a mold of the valve body 21 and is configured to be divided into two in the front-rear (depth) direction or the left-right direction on the drawing. The mold 40 is provided with a filling hole 41 of thermoplastic resin, and extraction holes 43a and 43b of cores 42a and 42b (for forming a gas vent passage) are provided coaxially.

  In the inner ring and core setting step, a ring body 22 formed in advance from a thermosetting resin is fitted into one of the two cores 42a and 42b. The mold 40 is opened in two, and the core 42b and the other core 42a are housed inside thereof. The ends of the cores 42a and 42b are positioned in a predetermined butted state through coaxial extraction holes 43a and 43b.

  In the filling process of the thermoplastic resin, when the cores 42a and 42b are positioned in a predetermined butted state, the mold 40 is closed to one, and the thermoplastic resin (giving fluidity by heating) passes through the filling hole 41. Is injected into the mold 40.

  In the mold drawing step after cooling and solidification, the two cores 42a and 42b are drawn out in the opposite directions from the closed mold 40 through the drawing holes 43a and 43b. Thereafter, the mold 40 is opened in two, and the molded product remaining inside the mold 40 is projected, whereby the valve body 21 containing the ring body 22 is obtained.

  By such a process, the valve body 21 including the link body 22 can be efficiently manufactured based on a simple method using the cores 42a and 42b. The gas vent valve 20 is completed when the valve body 30, the spring 32, and the spring receiver 33 are accommodated in the valve body 21 and the cap 29 is attached.

  5 and 6 show another form of the ring body 22, and the ring body 22 is provided with an opening 22c that forms a valve seat 23c (valve seat) on the bottom 22b of the ring 22a. The ring body 22 is integrally formed from a thermosetting resin that is excellent in electrolytic solution resistance and is not easily deformed by heat, as in the case described above. The diameter of the opening 22c is set to be substantially the same as that of the small diameter passage 23a of the gas vent passage 23.

  In the step of creating the valve body 21, the ring body 22 is fitted to the tip of the core 42b, and the other core 42a is inserted into the opening 22c inside the mold 40, and the cores 42a, 42b. Is positioned in a predetermined butted state. Thereafter, the valve body 21 as shown in FIG. 5 is obtained by the same filling process and mold release process as in FIG. In FIG. 5, the same parts as those in FIG.

  Since the ring body 22 is integrally formed from the thermosetting resin including the valve seat 23c, the ring body 22 can ensure a normal movement of the valve body 30 and a high degree of sealing performance when the valve is closed. The valve body 21 shown in FIGS. 1 and 5 is preferably formed from a thermoplastic resin that is excellent in electrolytic solution resistance and easily welded to heat.

It is sectional drawing explaining the structure of a gas vent valve. It is the front view explaining the structure of a valve body, and its top view. It is a perspective view of a ring body. It is explanatory drawing of the process of creating a valve body. It is the front view explaining the structure of a valve body, and its top view. It is a perspective view of a ring body. It is an external view of an electric double layer capacitor. It is a perspective view explaining the composition of an electric double layer capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Container 20 Gas vent valve 21 Valve body 22 Ring body 23 Gas vent passage 30 Valve body 31 Shaft part of valve body 32 Spring 33 Spring receiver

Claims (4)

  A gas vent that releases the gas from the valve seat when the internal pressure exceeds a predetermined value due to the gas generated inside the container that encloses the capacitor body composed of the positive electrode body, the negative electrode body, and the separator together with the electrolyte. In the valve, a gas vent comprising: a valve body made of a thermoplastic resin that forms a gas vent passage; and a ring body made of a thermosetting resin that is contained in the valve body and guides the movement of the valve body valve.   The degassing valve according to claim 1, wherein the ring body is formed from a thermosetting resin having an electrolytic solution resistance.   The gas vent valve according to claim 1, wherein the ring body made of a thermosetting resin integrally forms a valve seat.   Degassing that causes the valve body to move away from the valve seat and escape to the outside when the internal pressure exceeds a predetermined value due to the gas generated inside the container enclosing the capacitor body composed of the positive electrode body, the negative electrode body and the separator together with the electrolyte In the valve manufacturing method, a ring formed from a thermosetting resin is fitted to one of two cores that can advance and retreat on the same axis, and the tip of the other core is abutted on the same end. In this state, the mold is clamped and the thermoplastic resin which has been given fluidity by heating is filled into the mold, and after cooling and solidification, the two cores are extracted from the mold in opposite directions, and the mold is removed. And a step of creating a valve body that encloses the ring body by opening and projecting a molded product.

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