JP2004247544A - Manufacturing method of polymer ptc element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a characteristic defect caused by thermal deterioration resulting from soldering or welding by connecting a lead terminal to a polymer PTC element main body without directly imparting heat in soldering or welding thereto in the case of connection. <P>SOLUTION: The electrode of a lead terminal 3 is bonded to a polymer PTC element main body 1 without imparting heat of soldering or welding to the polymer PTC element main body 1. Therefore, metal foil 2 that becomes the electrode is bonded and integrated to the lead terminal 3 in advance, and a mounting surface of the metal foil 2 is then bonded to the PTC element main body 1. The mounting surface of the metal foil 2 is roughened in advance. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a polymer PTC element having a positive temperature coefficient of resistance, which is used for protecting a battery or a circuit from overcurrent, and the polymer PTC element is used for a mobile phone, a video camera, a computer, and the like. It is suitable as an electronic component for protecting a circuit connected to the battery pack from overcurrent and overheating.
[0002]
[Prior art]
Conventionally known techniques include a structure in which an electrode provided on a polymer PTC element body and a lead terminal are soldered (see Patent Document 1 below), and a method in which an electrode provided on a polymer PTC element body and a lead terminal are soldered. (See Patent Literature 2 below) is known.
[0003]
Further, as for the electrode (metal foil) provided on the polymer PTC element main body, a structure in which the metal electrode having the unevenness of 0.1 to 100 μm on the surface is in direct physical contact with the polymer PTC element main body (see Patent Document 3 below) ), And a structure in which the material of the electrode irregularities (microrough) is limited to Ni and directly in physical contact with a conductive polymer element (including polymer PTC) (see Patent Document 4 below). However, it does not mention a method for forming irregularities on the electrode.
[0004]
Further, as an electrode of a polymer PTC element main body, use of a metal plate whose surface in contact with the surface of the element main body is roughened is disclosed (see Patent Document 5 below).
[0005]
[Patent Document 1] Japanese Utility Model Laid-Open No. 2-146401 [Patent Document 2] Japanese Patent Application Laid-Open No. 2-268402 [Patent Document 3] U.S. Pat. No. 4,689,475 [Patent Document 4] U.S. Pat. [Patent Document 5] Japanese Patent Publication No. 5-9921 [0006]
[Problems to be solved by the invention]
In the case of a structure in which the electrodes provided on the polymer PTC element body and the lead terminals are connected by soldering or welding, it has been difficult to avoid thermal degradation to the polymer PTC element body during soldering or welding. As a result, the characteristics of the polymer PTC element main body are inferior and the yield is reduced.
[0007]
In view of the above, a first object of the present invention is to connect a lead terminal to a polymer PTC element body without directly applying heat at the time of soldering or welding, so that heat generated by soldering or welding can be obtained. An object of the present invention is to provide a method for manufacturing a polymer PTC element capable of preventing occurrence of characteristic failure due to deterioration.
[0008]
A second object of the present invention is to provide a method of manufacturing a polymer PTC element, in which the connection strength of a lead terminal to a polymer PTC element body is increased, the manufacturing yield is improved without requiring a special process, and the manufacturing can be performed at low cost. Is to provide.
[0009]
Other objects and novel features of the present invention will be clarified in embodiments described later.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a method of manufacturing a polymer PTC element according to the invention of claim 1 of the present application comprises the steps of: connecting a lead terminal electrode portion to the PTC element body without applying heat by soldering or welding to the polymer PTC element body. It is characterized by being joined to.
[0011]
The method for manufacturing a polymer PTC element according to the invention of claim 2 of the present application is the method according to claim 1, wherein a metal foil serving as the electrode portion is previously joined and integrated with the lead terminal, and then the mounting surface of the metal foil is connected to the PTC element. It is characterized by being joined to the main body.
[0012]
The method for manufacturing a polymer PTC element according to the invention of claim 3 of the present application is the method according to claim 1, wherein a hoop-shaped terminal in which the lead terminals are connected is used, and a long metal foil serving as an electrode portion is bonded to the hoop-shaped terminal in advance. After being integrated, the mounting surface of the long metal foil is joined to the sheet-like PTC element main body, and thereafter, unnecessary portions of the hoop-shaped terminal, the long metal foil and the sheet-like polymer PTC element main body are removed. Then, each lead terminal and the polymer PTC element main body are separated.
[0013]
A method for manufacturing a polymer PTC element according to the invention of claim 4 of the present application is characterized in that, in claim 2 or 3, a nodular irregularity is formed on the mounting surface of the metal foil.
[0014]
In the method for manufacturing a polymer PTC element according to claim 5 of the present invention, in claim 1, the mounting surface of the electrode portion of the lead terminal is roughened by forming nodular irregularities in advance by plating. The mounting surface is joined to the PTC element body.
[0015]
The method of manufacturing a polymer PTC element according to claim 6 of the present invention is characterized in that, in claim 1, the mounting surface of the electrode portion of the hoop-shaped terminal to which the lead terminal is connected is formed by forming a nodular unevenness by plating in advance. The mounting surface is bonded to the sheet-shaped PTC element body, and then unnecessary portions of the hoop-shaped terminal and the sheet-shaped polymer PTC element body are removed to separate lead terminals and the polymer PTC element body. It is characterized by being separated.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a method for manufacturing a polymer PTC element according to the present invention will be described with reference to the drawings.
[0017]
A first embodiment of a method for manufacturing a polymer PTC element according to the present invention will be described with reference to FIGS. FIG. 1 shows an outline of a manufacturing method in the case of the first embodiment, and FIG. 2 shows a polymer PTC element obtained by the manufacturing method. FIG. 3 shows a process flow in the case of mass production using a hoop-shaped lead terminal, and FIGS. 4 to 6 show the description of each process.
[0018]
First, the outline of the manufacturing method will be described with reference to FIGS. In these figures, 1 is a polymer PTC element main body, 2 is a metal foil (electrode portion) to be bonded to both surfaces of the polymer PTC element main body, and 3 is a lead terminal. Here, the lead terminal 3 is made of Ni or Ni alloy or the like having a thickness of about 0.1 mm, and the metal foil 2 has a thickness of 25 μm. Suitable materials include Ni and Cu. Good results are obtained in characteristics. The mounting surface (electrode portion) of the metal foil 2 on the main body of the polymer PTC element is roughened, and more preferably a nodule (difference of unevenness is about 5 to 15 μm, and the middle part to the base part is narrowed with respect to the head. It is desirable that a large number of shapes) are formed and roughened to increase the connection strength.
[0019]
First, in step # 1 of FIG. 1A, the lead terminals 3 are joined to the metal foil 2 by soldering or welding. Then, in step # 2, the lead terminals 3 are formed on both surfaces of the polymer PTC element body 1 as electrode portions respectively. The mounting surface of the integrated metal foil 2 is joined by hot pressing.
[0020]
The soldering temperature of the lead terminal 3 and the metal foil 2 serving as the electrode portion is about 200 ° C., and much higher in the case of welding. Such a high temperature of about 200 ° C. or more at the time of soldering or welding gives thermal deterioration to the polymer PTC element main body 1 and eventually causes poor characteristics. Therefore, after the lead terminal 3 and the metal foil 2 are joined and integrated in advance by soldering or welding, the metal foil 2 as an electrode part of the lead terminal 3 and the polymer PTC element main body 1 are joined by hot pressing. The joining temperature by this hot press is about 150 ° C., and this temperature does not cause thermal degradation to the polymer PTC element body 1. The polymer PTC element main body 1 is softened at about 150 ° C., and is bonded along the rough surface of the metal foil 2 having irregularities as it is.
[0021]
As a result, as shown in FIGS. 1B and 2, a polymer PTC element in which the metal foil 2 serving as the electrode portion of the lead terminal 3 is securely bonded to the polymer PTC element main body 1 is obtained.
[0022]
As described above, in the manufacturing method according to the first embodiment, since the temperature of about 200 ° C. for soldering or welding is not directly applied to the polymer PTC element main body 1, the thermal deterioration of the polymer PTC element main body 1 and the accompanying The occurrence of characteristic defects can be avoided. Also, by roughening the mounting surface of the metal foil 2 which will be the electrode part of the lead terminal 3, the bonding strength of the lead terminal 3 to the polymer PTC element main body 1 can be sufficiently ensured. If a roughening treatment having a large number of nodules is performed on the surface, further improvement in bonding strength can be achieved.
[0023]
Next, a method for manufacturing a polymer PTC element will be specifically described based on a process flow in the case of mass production using the hoop-shaped lead terminal of FIG.
[0024]
First, as shown in FIG. 4A, a hoop-shaped terminal 30 having a series of lead terminals is supplied by a reel, solder 37 is printed on the hoop-shaped terminal 30 by a solder printing machine, and a long metal foil is used. The (conductive member) 20 is supplied by a roll, is positioned on the hoop-shaped terminal 30, is superposed, and is supplied to a reflow furnace. As a result, the hoop-shaped terminal 30 in the metal foil soldered state shown in FIG. 4B is manufactured. The material of the hoop-shaped terminal 30 is Ni or a Ni alloy or the like, and the metal foil 20 is preferably Cu, Ni, or the like. However, a Cu foil plated with Ni or Ni has a good characteristic. The mounting surface of the metal foil 20 on the sheet-shaped polymer PTC element main body 10 is roughened, and is preferably a nodule (difference of unevenness is about 5 to 15 μm, and a middle part or a base part is narrowed with respect to a head part). Many shapes) are formed.
[0025]
Then, the hoop-shaped terminal with a metal foil is cut into a predetermined length (strip) by a cutting machine (to match the length of the sheet-shaped polymer PTC element body 10), and then, as shown in FIG. The sheet-shaped polymer PTC element body 10 is positioned and set (placed) on the hoop-shaped terminal 30 (on the mounting surface of the metal foil 20). Then, as shown in FIG. 5A, the upper hoop-shaped terminal 30 with a metal foil is positioned on the sheet-shaped polymer PTC element body 10 positioned and mounted on the lower hoop-shaped terminal 30 with a metal foil. It is placed (the mounting surface of the metal foil 20 is brought into contact with the sheet-shaped polymer PTC element body 10). As shown in FIG. 5B, the sheet-shaped polymer PTC element main body 10 is positioned between the upper and lower hoop-shaped terminals 30 with metal foil, and is placed in a bonding mold (jig) 40 in a state of being sandwiched therebetween. That is, the upper and lower hoop-shaped terminals 30 with metal foil and the sheet-shaped polymer PTC element body 10 are arranged between the lower mold 41 and the upper mold 42 of the bonding mold 40, and the molds 41 and 42 are joined. Then, the bonding mold 40 is hot-pressed as shown in FIG.
[0026]
As a result, as shown in FIG. 6 (A), a component chain 50 in which the sheet-shaped polymer PTC element main body 10 is integrally joined between the upper and lower hoop-shaped terminals 30 with metal foil is obtained. After the components 50 are gradually cooled, EB crosslinking is performed by electron beam irradiation. Unnecessary portions between the individual lead terminals 3 are punched out of the component string 50 by pressing as shown in FIG. 6B (the sheet-shaped polymer PTC element body 10 is separated into individual polymer PTC element bodies 1). 6) Then, unnecessary ear portions 31 of the hoop-shaped terminal 30 are cut off as shown in FIG. Thus, the product shape of the single polymer PTC element shown in FIG. 6D is obtained.
[0027]
A second embodiment of the method for producing a polymer PTC element according to the present invention will be described with reference to FIGS. 7 and 8 show an outline of a manufacturing method in the case of the second embodiment. FIG. 9 shows a process flow in the case of mass production using a hoop-shaped lead terminal, FIGS. 10 to 12 show the description of each process, respectively, and FIG. 13 shows a state in which the lead terminal is roughened and the polymer PTC element body. This shows the state of bonding with.
[0028]
First, an outline of the manufacturing method will be described with reference to FIGS. In these figures, 1 is a polymer PTC element main body, and 3 is a lead terminal to be bonded to both surfaces of the polymer PTC element main body, respectively. Here, the lead terminal 3 is made of Ni or a Ni alloy or the like, but the mounting surface of the electrode portion 35 which is a bonding portion to the polymer PTC element main body 1 is roughened by electroplating or chemical plating of Ni, Cu or the like. Has been integrated. In this roughening treatment, as shown in FIG. 13 (A), a large number of nodules 36 (a shape in which the middle part or base part is constricted with respect to the head with an unevenness of about 5 to 15 μm) are formed on the plating surface itself. Is desirable. For example, formation of a nodule by electroplating is obtained by flowing a plating current in a pulsed manner. Ni, which is a metal deposited on the electrode portion 35 of the lead terminal 3 by electroplating or chemical plating, has a particularly good characteristic.
[0029]
Then, as shown in FIG. 7A, the electrode portions 35 (mounting surfaces) after the surface roughening treatment of the lead terminals 3 are respectively brought into contact with both surfaces of the polymer PTC element body 1 and joined by hot pressing. The joining temperature by this hot press is about 150 ° C., and this temperature does not cause thermal degradation to the polymer PTC element body 1. The polymer PTC element main body 1 is softened at about 150 ° C., and a large number of nodes 36 are formed as shown in FIG.
[0030]
Thereby, as shown in FIG. 7B, a polymer PTC element in which the electrode portion 35 of the lead terminal 3 is securely joined to the polymer PTC element main body 1 is obtained.
[0031]
Thus, also in the manufacturing method of the second embodiment, by eliminating the steps of soldering and welding the lead terminals, it is possible to avoid the thermal degradation of the polymer PTC element main body 1 and the occurrence of the characteristic failure associated therewith. Further, by roughening the mounting surface of the lead terminal 3 and its electrode portion 35, the bonding strength of the lead terminal 3 to the polymer PTC element main body 1 can be sufficiently ensured. If the surface roughening treatment with nodules is performed, the joint strength can be further improved.
[0032]
Next, a method for manufacturing a polymer PTC element will be specifically described based on a process flow in the case where mass production is performed using a hoop-shaped lead terminal having roughened electrode portions in FIG.
[0033]
First, as shown in FIG. 10A, a hoop-shaped terminal 30 having a series of lead terminals (however, as shown in FIG. 13A, a large number of nodules (an unevenness of about 5 to 15 μm by electroplating or chemical plating). ) Are integrally formed and the electrode part is subjected to a surface roughening treatment), and the hoop-shaped terminal is cut into a predetermined length (strip) by a cutting machine. This is to match the length of the sheet-shaped polymer PTC element body 10. The material of the hoop-shaped terminal 30 is Ni or a Ni alloy or the like, and Cu or Ni is suitable for the electroplating or chemical plating for roughening the mounting surface of the electrode portion. Is out.
[0034]
Thereafter, the sheet-shaped polymer PTC element main body 10 is positioned and set (placed) on the hoop-shaped terminal 30 (on the roughened mounting surface of the electrode portion) as shown in FIG. 10B. Then, as shown in FIG. 11A, the upper roughened hoop-shaped terminal 30 is positioned and mounted on the sheet-shaped polymer PTC element main body 10 positioned and mounted on the lower hoop-shaped terminal 30. (The mounting surfaces of the electrode portions are brought into contact with the sheet-shaped polymer PTC element body 10, respectively.) As shown in FIG. 11 (B), the sheet-shaped polymer PTC element main body 10 is positioned between the hoop-shaped terminals 30 which have been subjected to the upper and lower surface roughening treatment, and is placed on the bonding mold 40 in a state of being sandwiched therebetween. That is, the three members of the hoop-shaped terminal 30 and the sheet-shaped polymer PTC element main body 10 that have been subjected to the upper and lower surface roughening treatment are arranged between the lower mold 41 and the upper mold 42 of the bonding mold 40 and the molds 41 and 42 are arranged. And the bonding mold 40 is hot-pressed as shown in FIG.
[0035]
As a result, as shown in FIG. 12 (A), a component chain 50 in which the sheet-shaped polymer PTC element main body 10 is joined and integrated between the upper and lower hoop-shaped terminals 30 is obtained. After the components 50 are gradually cooled, EB crosslinking is performed by electron beam irradiation. Unnecessary portions between the individual lead terminals 3 are punched out by pressing with respect to the component string 50 as shown in FIG. 12B (the sheet-shaped polymer PTC element body 10 is separated into individual polymer PTC element bodies 1). 12) Then, unnecessary ear portions 31 of the hoop-shaped terminal 30 are cut off as shown in FIG. Thereby, the product shape of the polymer PTC element of FIG. 12D is obtained.
[0036]
Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims.
[0037]
【The invention's effect】
As described above, according to the method of manufacturing a polymer PTC element according to the present invention, the metal foil to be the electrode portion of the lead terminal is previously integrated with the lead terminal by soldering or welding, or By pre-roughening the surface to be the electrode part by electroplating or chemical plating, it is not necessary to apply heat by soldering or welding to the polymer PTC element body, and it is possible to eliminate characteristic defects due to thermal deterioration. it can.
[0038]
Further, in the case where the metal foil is roughened and a large number of nodules are formed and roughened in the roughening process of the electrode portion of the lead terminal, the bonding strength of the lead terminal to the polymer PTC element body is further increased. Improvement can be achieved.
[0039]
Further, there is an advantage that the production efficiency and the yield can be improved and the production can be performed at low cost.
[Brief description of the drawings]
FIG. 1 is a first embodiment of a method for producing a polymer PTC element according to the present invention, and is an explanatory view schematically showing the production method.
FIG. 2 is a perspective view showing a product shape of a polymer PTC element obtained in the first embodiment.
FIG. 3 is a process flow chart in the case of manufacturing using a hoop-shaped terminal in the first embodiment.
FIG. 4 is an explanatory view showing steps from supply of a hoop-shaped terminal to mounting of a sheet-shaped polymer PTC element main body in the process flow of FIG. 3;
FIG. 5 is an explanatory view showing a process from mounting of the sheet-shaped polymer PTC element main body between upper and lower hoop-shaped terminals to hot pressing in the process flow of FIG. 3;
FIG. 6 is an explanatory view showing a process of separating unnecessary parts of a series of parts joined by sandwiching a sheet-shaped polymer PTC element body between upper and lower hoop-shaped terminals in the process flow of FIG. 3 to completion of a product shape. .
FIG. 7 is an explanatory view showing an outline of a manufacturing method according to a second embodiment of the present invention.
FIG. 8 is an exploded perspective view of the same.
FIG. 9 is a process flow chart in the case of manufacturing using a hoop-shaped terminal in the second embodiment.
FIG. 10 is an explanatory view showing steps from supply of a hoop-shaped terminal to mounting of a sheet-shaped polymer PTC element main body in the process flow of FIG. 9;
11 is an explanatory diagram showing a process from placing the sheet-shaped polymer PTC element body between upper and lower hoop-shaped terminals to hot pressing in the process flow of FIG. 9;
FIG. 12 is an explanatory diagram showing a process of separating unnecessary parts of a series of parts joined by sandwiching a sheet-shaped polymer PTC element body between upper and lower hoop-shaped terminals in the process flow of FIG. 9 to completion of a product shape. .
FIG. 13 is a cross-sectional view showing a roughened state of the electrode portion of the hoop-shaped terminal and a joined state of the polymer PTC element body and the electrode portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Polymer PTC element main body 2, 20 Metal foil 3 Lead terminal 10 Sheet-shaped polymer PTC element main body 30 Hoop-shaped terminal 35 Electrode part 36 Nodule 40 Bonding mold 50 Parts connection

Claims (6)

A method for manufacturing a polymer PTC element, comprising joining an electrode portion of a lead terminal to the PTC element body without applying heat by soldering or welding to the polymer PTC element body. 2. The method for manufacturing a polymer PTC element according to claim 1, wherein a metal foil serving as the electrode portion is bonded and integrated in advance to the lead terminal, and then a mounting surface of the metal foil is bonded to the PTC element body. Using a hoop-shaped terminal in which the lead terminals are connected, a long metal foil serving as an electrode portion is bonded and integrated in advance to the hoop-shaped terminal, and then the mounting surface of the long metal foil is attached to the sheet-shaped PTC element body. 2. The polymer PTC according to claim 1, wherein the polymer PTC is joined, and thereafter, unnecessary portions of the hoop-shaped terminal, the long metal foil and the sheet-shaped polymer PTC element body are removed to separate the lead terminal and the polymer PTC element body. Device manufacturing method. 4. The method for producing a polymer PTC element according to claim 2, wherein nodular irregularities are formed on the mounting surface of the metal foil. 2. The manufacturing method of a polymer PTC element according to claim 1, wherein the mounting surface of the electrode portion of the lead terminal is roughened in advance by forming nodular irregularities by plating, and the mounting surface is joined to the PTC element body. Method. The mounting surface of the electrode portion of the hoop-shaped terminal in which the lead terminals are connected is roughened by forming nodular irregularities by plating in advance, and the mounting surface is joined to the sheet-like PTC element main body. 2. The method of manufacturing a polymer PTC element according to claim 1, wherein unnecessary parts of the hoop-shaped terminal and the sheet-shaped polymer PTC element main body are removed and separated into individual lead terminals and the polymer PTC element main body.

Images