JP2005116341A - Thermostat protector and thermostat sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure the long term stability of a thermo sensor of a type in which the elastic deformation energy of an elastic body supporting elastic deformation energy by jointing and fixing with a fusible material such as solder is operated by being released by the melting of the fusible body and to improve the reliability of the action of a thermo protector using such a thermo sensor. <P>SOLUTION: A thermo sensor A is interposed between a pair of electrodes 41, 42, which uses the melting point or softening point of a fusible material 2 as an action temperature in which, in a state both ends of an elastic conductive material with a curvature radius r being overlapped, the conductive material is formed in a larger diameter into an annular body 1 of a radius R (R>r) and both the ends are jointed with a fusible material 2 and given elastic deformation energy, and by the release of the elastic deformation energy due to the melting or softening of the fusible material 2, the conductive material is shrunk to the annular body of the curvature radius r. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thermoprotector whose operating temperature is the melting point or softening point of a fusible material and a thermosensor used in the thermoprotector.

Accumulated elastic strain energy is detected as a thermo protector that detects abnormal heat generation in electronic and electrical devices, cuts off the device from the power supply by a cut-off operation based on this detection, prevents the device from overheating, and prevents the occurrence of fire. There are elastic strain energy types and thermal stress types such as bimetal switches.
As the elastic strain energy type, for example, as shown in FIG. 8 (a), the elastic metal ring 1 ′ is forcibly bent flat, and the bending elastic metal ring 1 ′ is resisted against the bending reaction force and a pair of electrodes 4 ′. , 4 ′ is fixed with a soluble alloy (solder) 2 ′ having a predetermined melting point, and elastic strain energy is accumulated. When the ambient temperature is raised to the melting point of the soluble alloy 2 ′ and the soluble alloy is melted, As shown in FIG. 8B, there is known one that releases the elastic strain energy of the elastic metal ring 1 ′ and disconnects the connection between the elastic metal ring 1 ′ and one electrode 4 ′ to cut off the energization. (See Patent Document 1).
Further, as shown in FIG. 9 (a), a pellet 2 ′ having a predetermined melting point, a seat plate 15 ′, a compression spring 1 ′, and a seat plate 16 from one end side in a metal case 14 ′ having a lead terminal 13 ′ attached to one end. 'Is sequentially accommodated, and the contact 42' whose outer periphery is slidably contacted with the inner surface of the metal case is accommodated, and the lead pin through bushing 17 'is fixed to the other end side of the metal case 14'. A trip spring 18 'is assembled between the lead terminal 13', the metal case 14 ', the contact 42', and the lead pin 41 ', and the ambient temperature is raised to the melting point of the pellet 2'. When the pellet 2 'is melted, the compression stress of the compression spring 1' is released as shown in FIG. 9B, and the contact 42 'from the tip of the lead pin 41' by the compression stress of the tripping spring 18 '. Separated It is also known to cut off the conduction path, and it is called a so-called pellet type thermal fuse (see Non-Patent Document 1).
As described above, a bimetal switch is known as the thermal stress type.

JP 7-29481 A Page 818 of Electrical Engineering Handbook 1988

However, in the elastic strain energy type shown in FIG. 8, the joining and fixing part of the elastic metal ring 1 ′ by the soluble alloy 2 ′ is local and acts on the soluble alloy 2 ′ based on the reaction force of the elastic metal ring 1 ′. Since the acting force (stress) per unit cross-sectional area is large, the soluble alloy 2 ′ is likely to undergo creep deformation, self-heating due to an increase in the resistance value of the joint portion based on this creep deformation often occurs. Stringing is also likely to occur, and there are concerns about operational errors and operational instability.
In the pellet type shown in FIG. 9, the structure is complicated even if the pellet can be uniformly compressed for pressure equalization by the seat plate, and the disadvantages in terms of downsizing and cost cannot be avoided.
Further, the bimetal type is a return type, and there is a risk that the operating temperature rises with time due to hysteresis as the ON / OFF repetition progresses.

  The purpose of the present invention is to guarantee the long-term stability of a thermosensor that operates with the elastic strain energy released by melting of the fusible material, which is supported by bonding and fixing with a fusible material such as solder. In addition, the reliability of the operation of the thermo protector using such a thermo sensor is improved.

  The thermoprotector according to claim 1 is formed by expanding the diameter of the elastic conductive material having a predetermined curvature radius into an annular body having a radius larger than the predetermined curvature radius, and joining the both ends with a soluble material. A thermosensor having an operating temperature at the melting point or softening point of the soluble material so that the elastic strain energy is applied and the elastic strain energy is released by melting or softening of the soluble material to reduce the diameter of the soluble material to the annular body having the predetermined curvature radius. Is held between a pair of electrodes.

  The thermo protector according to claim 2 is the thermo protector according to claim 1, wherein the elastic conductive material is a single metal, a laminate of metal and resin, or a mixture of resin and conductive particles.

  The thermo protector according to claim 3 is characterized in that, in the thermo protector according to claim 1 or 2, a fusible material is bitten by providing a hole, a dent or a notch in a joint surface of both ends of the elastic conductive material to be joined. And

  A thermo protector according to claim 4 is characterized in that, in the thermo protector according to any one of claims 1 to 3, the joint surfaces of both ends of the elastic conductive material to be joined are roughened.

  The thermo protector according to claim 5 is the thermo protector according to any one of claims 1 to 4, wherein the soluble material is a low melting point metal.

  The thermo protector according to claim 6 is the thermo protector according to any one of claims 1 to 4, wherein the soluble material is a thermoplastic resin.

  The thermo protector according to claim 7 is the thermo protector according to any one of claims 1 to 6, characterized in that the elastic conductive material annular body has a multi-coil shape.

  The thermo protector according to claim 8 is the thermo protector according to any one of claims 1 to 7, characterized in that the distance G between the electrodes is R> G> r.

  The thermo protector according to claim 9 is the thermo protector according to any one of claims 1 to 8, wherein the thermo sensor is pressurized by the elastic stress of the electrode.

  The thermo protector according to claim 10 is the thermo protector according to any one of claims 1 to 9, wherein a soluble conductive material having a melting point or a softening point lower than that of the soluble material is added to a contact portion between the electrode and the thermo sensor. It is characterized by.

  The thermo protector according to claim 11 is the thermo protector according to any one of claims 1 to 10, wherein a resistance material that melts or softens the soluble material by generating heat when energized is interposed at a contact portion between the electrode and the thermo sensor. It is characterized by that.

  The thermosensor according to claim 12 is formed by expanding or reducing the diameter of an elastic material having a radius of curvature different from that of an elastic material having a predetermined curvature radius, and joining the both ends with a soluble material. The operating temperature is the melting point or softening point of the soluble material so that elastic strain energy is applied and the elastic strain energy is released by melting or softening of the soluble material to reduce or expand the diameter of the annular body having the predetermined curvature radius. It is characterized by that.

The elastic strain energy of the elastic conductive material formed by expanding the diameter from the predetermined radius r to the radius R (R> r) by the slide at both ends is supported by the shear stress at the joint interface of the both ends joined by the soluble material. The shearing stress can be lowered by widening the joining area to stably maintain the joining interface.
In addition, since the substantial current path in the thermo protector is one electrode → the annular conductor made of an elastic conductive material → the other electrode, and the energization of the fusible material hardly occurs. Does not occur substantially. Furthermore, malfunction due to stringing can be prevented.
Therefore, stable operation can be guaranteed, accurate operation can be performed at the melting point or softening point of the fusible material, and the problem that the operating temperature rises over time due to hysteresis as the ON / OFF cycle of the bimetal type progresses is also eliminated. it can.

FIG. 1 shows the basic structure of a thermosensor according to the present invention.
FIG. 1 (a) shows an elastic conductive material bent to a radius of curvature r, the total length L is 2πr or more, and the overlap margin at both ends is (L−2πr).
1 (b) to 1 (c) show thermosensors, and as shown in FIG. 1 (b), the overlap of both ends is reduced by the circumferential expansion force, and the radius of the elastic conductive annular body 1 is made larger than the above r. The diameter is expanded to R, and the both ends are overlapped with the soluble material 2 as shown in FIG.
In this case, the circumferential compression reaction force increases as the diameter increases, and T represents the circumferential compression reaction force when the radius R is reached.

  In FIG. 1B, m represents a bending moment reaction force generated by increasing the elastic conductive material from the radius of curvature r to R, and the bending rigidity of the elastic conductive material is EI.

  m = EI [(1 / r) − (1 / R)]

The bending strain energy W, which is given by

  W = 2πR · m 2 / (2EI) = πR · m 2 / (EI)

Given in.
This bending strain energy W is balanced with the work W ′ performed by the circumferential expansion force. Since the work W ′ has an expansion distance of 2π (R−r) based on the circumferential expansion,

  W ′ = Tπ (R−r)

From W = W ’

  T = EI (Rr) / (r2R)

で与えられる。 If the area of the joint interface of the joint portion made of soluble material is S, the shear stress τ acting on the joint interface is

Given in.

  In the thermosensor, when the soluble material 2 is melted or softened due to an increase in the ambient temperature, the elastic bending strain energy is released, the diameter is restored from the radius R to the original radius r, and the ambient temperature is reduced to that of the soluble material. A melting point or softening point is detected.

The elastic conductive material 1 can be a single elastic metal, a laminate of an elastic metal and a synthetic resin, a laminate of an elastic synthetic resin and a metal, an elastic synthetic resin mixed with conductive particles, or the like. The elastic synthetic resin includes a fiber reinforced synthetic resin.
The conductive material includes a material having a relatively high specific resistance in addition to a metal having a high conductivity such as copper.
The fusible material 2 may be a low melting point fusible alloy such as solder or a thermoplastic resin. The melting point or softening point of the metal or synthetic resin of the elastic conductive material 1 is set lower than the melting point or softening point of the soluble material 2.

In the thermosensor according to the present invention, the shearing force τ represented by the above formula (1) is acting on the joint interface between both ends of the elastic conductive material joined with the soluble material. The joining interface must have a strength that can withstand this shearing force, and the shearing force τ becomes large due to the high elastic modulus (large E) of the elastic conductive material and the small size of the annular body radius r. Sometimes it is necessary to increase the shear strength of the bonding interface. Therefore, it is effective to provide a hole, a dent, or a notch in one or both of the surfaces to be joined so that the fusible material is bitten in, or to have one or both of the surfaces to be joined as a rough surface to provide an anchor effect.
When the elastic conductive material is an elastic metal simple substance, a low melting point alloy such as solder can be used as the soluble material, and in this case, the joining with the soluble material is performed by interposing a solder sheet between the overlapping ends of the elastic conductive material, It can be performed by applying a flux between the solder sheet and the elastic metal material and then heating and melting the solder. For the heating, electric heating, electromagnetic induction heating, or the like can be used.

In order to manufacture the thermosensor according to the present invention, for example, a mandrel (radius R) is inserted into the elastic conductive annular body having the radius r to expand the annular body to the radius R, and both ends of the annular body are overlapped. Can be joined with a soluble material.
The elastic conductive annular body having the radius r before the diameter expansion is obtained by cutting the elastic conductive cylindrical body having the radius r into a spiral shape and cutting with a length of one pitch or more of the spiral, an elastic conductive strip or a linear body. It can be obtained by, for example, a method in which a spiral mandrel is wound around a rotating mandrel and bent, and this is sent out from the tip of the mandrel and cut by a length of one pitch or more of the spiral.

If bending strain remains in the elastic conductive ring having the radius r, the residual strain is released by heating at the time of joining with the soluble material for obtaining the elastic conductive ring having the radius R.
In a thermosensor having such an elastic conductive ring, the radius after the above-described operation, that is, after the elastic conductive ring having a radius R is reduced by melting or softening of the soluble material, is slightly larger than the radius r. If the radius is sufficiently smaller than the radius R, the residual strain is acceptable.

The elastic conductive material of the elastic conductive ring having the radius r may be any of a band-shaped material and a linear material (the cross section is, for example, round or substantially square). When the elastic conductive material is a laminate of a metal and a synthetic resin, a strip-shaped material is usually used. The number of laminated layers can be three or more.
The number of turns of the annular body may be multiple as well as the single number shown in FIG. If multiple, the bonding area S in Formula (1) can be increased, the shear reaction force T can be dispersed over a wide bonding interface, and the reduction of the shear stress τ at the bonding interface can be promoted. Even if the elastic modulus E is high and the elastic modulus E is high, the shear stress τ can be kept low to ensure the stability of the thermosensor.

2 (a) is a plan view (perspective view) showing an embodiment of a thermoprotector according to the present invention, FIG. 2 (b) is a side view, and FIG. 2 (c) is FIG. 2 (a). FIG.
In FIG. 2, 3 is an insulator housing to which a pair of electrode members 41 and 42 are fixed. As shown in FIG. 4, the electrode member includes a main body portion 411 (421) and a flat lead portion 412 (422). The insulator housing 3 can be manufactured by, for example, injection molding, and a synthetic resin having a softening point higher than the melting point or softening point of the soluble material can be used as the charge resin. The electrode material is fixed by setting a pair of electrode materials in a mold and injection molding the housing, or forming a housing with a slit, inserting the main body of the electrode material into the slit, and placing the main body on the inner surface of the housing. It can be performed by fixing with an adhesive or riveting.
In FIG. 2, reference numeral 51 denotes a base insulator fitted or adhered to the bottom side of the housing 3, for example, a ceramic plate, an FRP plate such as a glass fiber reinforced polyester resin plate, a heat resistant plastic plate, or the like.
A is a thermosensor according to the present invention, and its outer diameter R is elastically held between the main body portions 411 and 421 of the electrodes, with the outer diameter R being larger than the interval G between the main body portions 411 and 421 of the electrodes 41 and 42. When the elastic conductive annular body 1 of the thermosensor A is a laminate of a metal foil and a synthetic resin, the outer peripheral surface of the annular body is a metal foil surface.
Reference numeral 52 denotes a cover plate fitted or bonded to the upper surface side of the housing 3. For example, a ceramic plate, an FRP plate such as a glass fiber reinforced polyester resin plate, a heat resistant plastic plate, or the like can be used.

In FIG. 2A, the pressure p based on the compression reaction force of the thermosensor is applied to the contact portion between the body portions 411 and 421 of the electrode and the thermosensor A, and the contact portion is in surface contact. . Therefore, the electrical resistance of the path of the electrode 41 → the conductive material of the thermosensor A → the electrode 42 can be sufficiently lowered, and good electrical conductivity can be guaranteed.
In the above thermo protector, when the soluble material of the thermo sensor A is melted or softened due to an increase in the external temperature, the elastic bending strain energy stored in the elastic conductive ring (radius R) of the thermo sensor is released and shown in FIG. Thus, the radius of the annular body 1 is restored to the original radius r (R> r) and the contact between the electrodes 41 and 42 and the thermosensor is released.

The thermo protector according to the present invention can be used for overheat protection of electronic and electrical equipment.
According to this protection, when the device abnormally generates heat due to overcurrent, the fusible material of the thermosensor is melted or softened by the generated heat, and the energization of the device is interrupted by releasing the contact between the electrode and the thermosensor. Therefore, when the temperature of the device almost reaches the melting point or softening point Tm of the fusible material, it is possible to prevent the temperature rise of the device from exceeding the temperature Tm by interrupting the power supply to the device due to the operation of the thermo protector. By setting the melting point or softening point of the fusible material according to the temperature, abnormal heat generation due to the overcurrent of the device can be suppressed, and thus the device can be prevented from being fired.

In the thermo protector according to the present invention, the main stress acting on the fusible material is the shear stress, and as apparent from the equation (1), the shear stress τ is made sufficiently small by increasing the area S of the joining interface by the fusible material. Therefore, it is possible to avoid creep of the soluble material and to guarantee excellent stability. Furthermore, it is possible to increase the shear strength of the bonding interface by providing holes, dents, and notches on the surfaces to be joined, so that fusible materials can penetrate, and the surface to be joined has a rough surface to provide an anchoring effect, thereby increasing the shear strength of the joint interface. Can guarantee.
In FIG. 2A, the contact pressure p between the thermosensor and the electrode only acts as a bending moment on the joint portion formed by the soluble material 2, and the stress acting on the joint portion by this bending moment is a shear stress. Therefore, the stability guarantee can be ensured regardless of the action of the contact pressure p.

An elastic metal material may be used for at least one of the pair of electrodes, and the contact pressure may be generated by the elasticity of the electrodes.
Even if a conductive material is added facing the contact portion between the thermosensor and the electrode, the resistance between the electrode and the thermosensor can be sufficiently lowered to ensure the above-described good conductivity. As the conductive material, a conductive synthetic resin mixed with conductive particles such as a soluble alloy or metal particles whose melting point or softening point is lower than the melting point or softening point of the soluble material can be used. It has been adjusted to such an extent that the stringing of the conductive material at the time can be avoided.
In this thermo protector, since the conductive material is melted or softened before the fusible material is melted or softened, smooth operation can be ensured also in this thermo protector.

In the thermosensor or thermoprotector according to the present invention, one electrode → the contact portion between this electrode and the conductive surface of the thermosensor outer periphery → the conductive material of the thermosensor outer periphery → the conductive surface of the thermosensor outer peripheral surface and the other electrode The contact part → the other electrode is the main energization path, and the fusible material is not substantially involved in this energization path. It can be selected only from the melting characteristics without being restricted by the resistance value.
Recently, it has been required in the field of soldering to use a low melting point alloy that does not contain a metal element harmful to living systems such as Pb and Cd for environmental hygiene. In the present invention, the soluble material has a specific resistance value. A free low melting point alloy such as lead or Cd can be used without any restrictions.

  For example, phosphor bronze can be used for the elastic metal material 1. When using a resin as an elastic material, the melting point or softening point of a fusible material such as FRP in which the resin (thermoplastic resin or thermosetting resin) is reinforced with fibers such as glass fiber, metal fiber, synthetic fiber, high-rigidity engineering plastic, etc. Can be selected in consideration of the relative relationship with. As the elastic material, a composite of an elastic metal material and a synthetic resin, for example, a laminate of a phosphor bronze plate and a polyamide film can be used.

  Engineering materials such as polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, polybutylene terephthalate, polyphenylene oxide, polyethylene sulfide, polysulfone, etc. Engineering plastics such as plastic, polyacetal, polycarbonate, polyphenylene sulfide, polyoxybenzoyl, polyether ether ketone, polyetherimide, polypropylene, polyvinyl chloride, polyvinyl acetate, polymethyl methacrylate, Polyvinylidene chloride, polytetrafluoroethylene, ethylene polytetrafluoroethylene copolymer, ethylene vinyl acetate copolymer (EVA), AS resin, ABS resin, ionomer, AAS Fat, can be selected ones of a desired melting point from in ACS resin.

  As the soluble alloy, it is preferable to use an alloy that does not contain elements harmful to biological systems such as Pb and Cd. The following composition [A] (1) 43% Sn ≦ 70%, 0 .5% ≦ In ≦ 10%, remaining Bi, (2) 25% ≦ Sn ≦ 40%, 50% ≦ In ≦ 55%, remaining Bi, (3) 25% Sn ≦ 44%, 55% In ≦ 74% 1% ≦ Bi 20%, (4) 46% Sn ≦ 70%, 18% ≦ In 48%, 1% ≦ Bi ≦ 12%, (5) 5% ≦ Sn ≦ 28%, 15% ≦ In 37%, remaining Bi (However, Bi ± 2%, In and Sn ± 1% are excluded based on Bi57.5%, In25.2%, Sn17.3% and Bi54%, In29.7%, and Sn16.3%, respectively. ), (6) 10% ≦ Sn ≦ 18%, 37% ≦ In ≦ 43%, remaining Bi, (7) 25% Sn ≦ 60%, 2 % ≦ In 50%, 12% Bi ≦ 33%, (8) 1 of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P in any one of (8) (1) to (7) 0.01 to 7 parts by weight in total of seeds or two or more kinds, (9) 33% ≦ Sn ≦ 43%, 0.5% ≦ In ≦ 10%, remaining Bi, (10) 47% ≦ Sn ≦ 49% 3 to 5 parts by weight of Bi are added to 100 parts by weight of 51% ≦ In ≦ 53%, (11) 40% ≦ Sn ≦ 46%, 7% ≦ Bi ≦ 12%, remaining In, (12) 0. 3% ≦ Sn ≦ 1.5%, 51% ≦ In ≦ 54%, remaining Bi, (13) 2.5% ≦ Sn ≦ 10%, 25% ≦ Bi ≦ 35%, remaining In, (14) (9 ) To (13) 100 parts by weight of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P or a total of 0.01 to 7 weights Addition, (15) 10% ≦ Sn ≦ 25%, 48% ≦ In ≦ 60%, remaining Bi is 100 parts by weight of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P Or the composition of In-Sn-Bi alloy such as addition of two or more kinds in a total of 0.01 to 7 parts by weight, [B] (16) 30% ≦ Sn ≦ 70%, 0.3% ≦ Sb ≦ 20% , Balance Bi, (17) (16) 100 parts by weight of Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge, P, or a total of 0.01 to 7 parts by weight, The composition of the Bi—Sn—Sb alloy such as [C] (18) 52% ≦ In ≦ 85%, the remaining Sn, (19) In 100 parts by weight of (18), Ag, Au, Cu, Ni, Pd, Composition of In—Sn based alloy such as addition of 0.01 to 7 parts by weight of one or more of Pt, Sb, Ga, Ge, and P, [D] (2 0) 45% ≦ Bi ≦ 55%, balance In, (21) One or two of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P in 100 parts by weight of the composition of (21) (20) In-Bi alloy composition such as addition of 0.01 to 7 parts by weight or more in total, [E] (22) 50% Bi ≦ 56%, remaining Sn, (23) 100 parts by weight of (22) Composition of Bi-Sn based alloy such as addition of 0.01 to 7 parts by weight in total of one or more of Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge, P, [F] (24 ) A total of 0.01 to 7 parts by weight of one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P is added to 100 parts by weight of In, (25) 90% ≦ In ≦ One type of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, P in 100 parts by weight of 99.9%, 0.1% ≦ Ag ≦ 10% Alternatively, two or more kinds are added in total 0.01 to 7 parts by weight, (26) 95% ≦ In ≦ 99.9%, 100% by weight of 0.1% ≦ Sb ≦ 5%, Au, Bi, Cu, Ni, The composition of the melting point suitable for the operating temperature of the thermosensor or thermoprotector from the composition of the In-based alloy such as 0.01 to 7 parts by weight of one or more of Pd, Pt, Ga, Ge, P added in total Can be selected.

  As the electrode material, a conductive metal such as nickel, copper, copper alloy such as phosphor bronze, or a conductive elastic metal or alloy can be used, and can be plated as necessary.

In the present invention, an elastic conductive material having a high specific resistance can be used. In a thermo sensor or thermo protector (referred to as a resistance type thermo protector) using a resistance material having a high specific resistance value as the conductive material of the elastic conductive material, the soluble material is melted or softened by the self-heating of the resistance material based on a predetermined current. The device can be protected not only from the temperature rise of the device itself but also from other causes. For example, a voltage fluctuation at the initial overcharge of a secondary battery, particularly a lithium ion secondary battery is detected, and a current for heating is applied to the resistance material based on this detection, and a soluble material is removed by self-heating of the resistance material. It can also be used to suppress overcharging by operating the thermosensor by melting or softening.
As the resistance material, an alloy material such as iron or chrome, or a synthetic resin material mixed with resistance powder such as metal oxide powder can be used.
Instead of using these resistance materials for the conductive material of the elastic conductive material, it is possible to interpose a resistor chip on the contact surface between the electrode and the thermosensor in the thermo protector of FIG.
FIG. 5 shows an example of the above-described secondary battery overcharge protection circuit. Between the charger E and the secondary battery B, a Zener diode D, a transistor Tr, and the resistance type thermoprotectors C1, C2 according to the present invention are provided. Connected.
Thus, when the terminal voltage of the secondary battery B is abruptly changed due to overcharge, the Zener diode D becomes conductive, and the secondary battery B and charge are connected to the thermoprotectors C1 and C2 by the conduction between the base and emitter of the transistor Tr. A current is supplied from the machine E as a power source, and the fusible material is melted or softened by the heat generated by the resistors of the thermo protectors C1 and C2, and the secondary battery B is disconnected from the charger E.

In the above embodiment, conductivity is imparted to the elastic material. However, the conductivity may be an optional requirement, and FIG. 6 (a) is a plan view before operation of an embodiment of such a thermo protector. FIG. 6B is a plan view after the same operation.
In FIG. 6A, reference numeral 3 denotes a housing, in which an electrode material 41 having a fixed contact portion 4110 and an electrode material 42 having a movable contact portion 4210 are fixed. Reference numeral 51 denotes a base plate fitted or bonded to the bottom side of the housing 3. A is a thermosensor, and an annular body having a radius R (R> r) in a state in which both ends of an annular elastic material (elastic metal material, elastic resin material such as FRP, composite elastic material, etc.) having a radius of curvature r are stacked. 1 is expanded in diameter and joined at both ends with a fusible material 2 to give elastic strain energy, and the elastic material is melted or softened to release the elastic strain energy to reduce the diameter to an annular body having the curvature radius r. The movable contact portion 4210 is mounted in the inner space of the housing behind the movable contact portion 4210, and the movable contact portion 4210 is brought into contact with the fixed contact portion 4110 by the elastic reaction force. The cover plate fitted on the upper side of the housing is not shown.

In this thermoprotector, the electrical connection is normally made in the path of the fixed contact portion of one electrode material → the contact surface between the fixed contact portion and the movable contact portion of the other electrode material → the other electrode material.
The operation of the thermo protector will be described. When the soluble material is heated to its melting point or softening point due to an increase in the external temperature, the thermo-sensor as shown in FIG. The sensor A is reduced in diameter to the radius r, the movable contact portion 4210 is detached from the fixed contact portion 4110, and the non-return energization is completed.

In any of the above-described thermosensors, the radius r of the original annular body before storing the elastic bending strain energy is set to r <R with respect to the radius R of the annular body after storing the elastic bending strain energy. Depending on the contact structure of the thermo protector, the radius r of the original annular body before storing the elastic bending strain energy can be set to r> R with respect to the radius R of the annular body after storing the elastic bending strain energy. Also in this case, the conductivity of the elastic material can be an essential requirement or an optional requirement depending on the contact structure of the thermoprotector.
FIG. 7 (a) shows a plan view before operation of an embodiment of the thermoprotector with r> R, and FIG. 7 (b) shows a plan view after the same operation.
In FIG. 7A, reference numeral 3 denotes a housing, which has a pair of electrode members 42 and 42 each having a movable contact portion 420 fixed thereto. Reference numeral 51 denotes a base plate fitted or bonded to the bottom side of the housing 3. A is a thermosensor, and an annular body having a radius r (R> r) in a state where both ends of an annular elastic material (elastic metal material, elastic resin material such as FRP, composite elastic material, etc.) having a radius of curvature R are stacked. 1 is reduced in diameter and joined at both ends with a fusible material 2 to give elastic strain energy, and is expanded into an annular body having the radius of curvature R by releasing the elastic strain energy by melting or softening the fusible material 2. In this manner, the electrode members 42 are accommodated between the contact portions 420 of the electrode members 42. The cover plate fitted on the upper side of the housing is not shown.

In this thermo-protector, it is normally connected by elastic contact of the movable contact portions of both electrode materials.
The operation of this thermo protector will be described. When the soluble material is heated to its melting point or softening point due to an increase in the external temperature, the bending strain energy of the annular elastic material 1 of the thermo sensor A is shown in FIG. Thus, the thermosensor A is expanded to a radius R, and the movable contact portions 420 and 420 are expanded by the expanded diameter, and the non-returning energization-off is completed.

  High energy density secondary batteries, such as lithium ion secondary batteries and lithium polymer secondary batteries, have a high heat generation temperature due to the high energy density, and the heat is detected so that the battery is de-energized. Although a protector is required, the thermo protector according to the present invention can be easily reduced in thickness and can be favorably incorporated into a battery pack, and can be suitably used as a thermo protector for a battery.

1 is a view showing a thermosensor according to the present invention. It is drawing which shows one Example of the thermo protector which concerns on this invention. It is drawing which shows the operation state of the thermo protector shown in FIG. It is drawing which shows the electrode in the thermoprotector shown in FIG. It is a circuit diagram which shows the usage example of the resistance type thermoprotector which concerns on this invention. It is drawing which shows the Example different from the above of the thermoprotector which concerns on this invention. It is drawing which shows the Example different from the above of the thermoprotector which concerns on this invention. It is drawing which shows the conventional thermo protector. It is drawing which shows an example different from the above of the conventional thermoprotector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic material 2 Soluble material A Thermo sensor 3 Housing 41 Electrode 42 Electrode

Claims (12)

In a state where both ends of the elastic conductive material having a predetermined curvature radius are overlapped, the diameter of the ring is increased to an annular body having a radius larger than the predetermined radius, and both ends are joined with a soluble material to give elastic strain energy. A thermosensor having a melting point or softening point of the fusible material as an operating temperature is sandwiched between a pair of electrodes so as to reduce the diameter to the annular body having the predetermined radius of curvature by releasing elastic strain energy by melting or softening. Thermo protector. 2. The thermoprotector according to claim 1, wherein the elastic conductive material is a single metal, a laminate of metal and resin, or a mixture of resin and conductive particles. 3. The thermo protector according to claim 1, wherein a fusible material is bitten by providing holes, dents, or notches on joint surfaces of both ends of the elastic conductive material to be joined. The thermo protector according to any one of claims 1 to 3, wherein a joining surface of both ends of the elastic conductive material to be joined is a rough surface. The thermoprotector according to claim 1, wherein the soluble material is a low melting point metal. The thermoprotector according to any one of claims 1 to 4, wherein the soluble material is a thermoplastic resin. The thermo-protector according to claim 1, wherein the elastic conductive material annular body has a multi-coil shape. The thermoprotector according to claim 1, wherein a gap G between the electrodes is R> G> r. The thermo protector according to claim 1, wherein the thermo sensor is pressurized by elastic stress of the electrode. The thermoprotector according to any one of claims 1 to 9, wherein a soluble conductive material having a melting point or a softening point lower than that of the soluble material is added to a contact portion between the electrode and the thermosensor. The thermoprotector according to any one of claims 1 to 10, wherein a resistor that generates heat by energization to melt or soften the soluble material is interposed at a contact portion between the electrode and the thermosensor. With both ends of an elastic material having a predetermined radius of curvature overlapped, an annular body having a radius different from that of the curvature radius is expanded or contracted, and both ends are joined with a soluble material to give elastic strain energy. A thermosensor characterized in that the melting point or softening point of the fusible material is set to the operating temperature so that the elastic body is contracted or expanded by releasing elastic strain energy by melting or softening.

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