JP4815151B2 - Thermal protection switch device and battery pack - Google Patents

Description

  The present invention relates to a thermal protection switch device that turns off a circuit by being heated by a heating body, and a battery pack that constitutes a protection circuit for protecting a secondary battery using the thermal protection switch device.

  In recent years, in various devices such as mobile phones, digital cameras, electric tools, and robots, battery packs that integrally include a secondary battery and a protection circuit have been widely used. This battery pack has, for example, a circuit configuration as shown in FIG.

  The battery pack 200 shown in FIG. 12 includes a rechargeable secondary battery 202 such as a lithium ion secondary battery, a lithium polymer secondary battery, a nickel hydride secondary battery, a nickel cadmium secondary battery, and the secondary battery 202. And a protection circuit 204 for preventing an excessive charge current from flowing or an excessive discharge current from flowing. That is, in the secondary battery 202 such as a lithium ion secondary battery, when the secondary battery 202 is excessively charged or an excessive discharge current flows through the secondary battery 202, characteristics such as cycle life are deteriorated, Inconveniences such as expansion and deformation of the battery occur. Therefore, between the pair of external terminals 206 and 208 connected to the positive electrode terminal and the negative electrode terminal of the secondary battery 202 in order to prevent such inconvenience. A protection circuit 204 is provided (for example, Patent Document 1).

The protection circuit 204 includes a MOSFET 210 as a switching element for cutting off a charging current when an excessive charging current flows in the secondary battery 202, and a case where an excessive discharging current flows in the secondary battery 202. MOSFET 212 as a switching element for interrupting the discharge current, and overcharge detection circuit 214 including a comparator that detects that the secondary battery 202 is excessively charged due to excessive charging current flowing through the secondary battery 202; An overdischarge detection circuit 216 including a comparator that detects that an excessive discharge current has flowed through the secondary battery 202, and an output from the overcharge detection circuit 214 when an excessive charge current has flowed through the secondary battery 202 In response to the detection signal, the MOSFET 210 is turned off to interrupt the charging current, and an excessive discharge current flows to the secondary battery 202. Those were Bei a logic circuit 218 that the MOSFET212 receives the detection signal output from the over-discharge detection circuit 216 turns off to cut off the discharge current.
JP-A-4-75430

  However, in the protection circuit 204 described above, a parasitic diode with the drain side in the forward direction is generated between the drains and the sources of the MOSFETs 210 and 212, so that a charging current and a discharging current with different current flow directions are combined into one. The MOSFET cannot be cut off, and requires two MOSFETs, a MOSFET 210 that cuts off the charging current and a MOSFET 212 that cuts off the discharging current, and accordingly, an overcharge detection circuit 214, an overdischarge detection circuit 216, and a logic circuit 218. As a result, the circuit configuration is complicated. In addition, due to the complexity of the circuit configuration and the like, there is a limit to downsizing of the protection circuit board formed by forming the protection circuit on the wiring board. As a result, there is a problem that the downsizing of the battery pack may be hindered.

  The present invention has been made in view of such circumstances, and a thermal protection switch device that enables downsizing of a protection circuit board and downsizing of a battery pack, and a secondary using the thermal protection switch device. It aims at providing the battery pack which comprised the protection circuit for protecting a battery.

In order to achieve the above object, the invention of claim 1 is a thermal protection switch device that turns off a circuit by being heated by a heating body, and includes a first support member and a second support member that are arranged at predetermined intervals. A frame body having a support member, and a first contact terminal disposed on the first support member on the first surface side of the frame body to constitute a contact point and extending from the contact point constitute a first attachment terminal. 1 wiring conductor and the 2nd wiring conductor which is arrange | positioned on the 2nd support member in the 1st surface side of the said frame body, and comprises a 2nd attachment terminal by extending from the said contact And a thermal switch element that is disposed between the contact points of the first wiring conductor and the second wiring conductor and turns off between the contact points when heated by a heating body, and the frame body. The first support member and the second A holding member that connects the holding members at an intermediate portion between the first surface and the second surface facing the first surface, and a connecting member that disposes the bimetal element on the first surface side, The frame body has an open shape in which the second surface side can dispose a heating body for heating the thermal switch element between the support members , and the first attachment terminal is the first support member So that the second surface of the second support member is flush with the second surface of the second support member, and the second mounting terminal is flush with the second surface of the second support member. The second surface position is bent outward .

According to a second aspect of the present invention, the thermal switch element according to the first aspect is provided with a movable contact member disposed between the contact points and a movable contact member when heated by a heating body. It is characterized by obtaining Bei the bimetal element to turn off between the act each contact.

  According to a third aspect of the present invention, in the frame according to the second aspect, the frame body is formed by forming the connecting member at an intermediate portion between the first surface and the second surface of the first support member and the second support member. A concave portion is formed on the second surface side of the connecting member, and the concave portion is open so that a heating body for heating the thermal switch element can be disposed.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a cover body that covers the thermal switch element is provided on a first surface side of the frame body.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the frame body is configured by fixing a first support member and a second support member with a wiring board. It is said.

  The invention of claim 6 is a battery pack having a first external terminal and a second external terminal, and a secondary battery for supplying power to the load device, and for protecting the secondary battery. And a protection circuit configured using the heat-sensitive protection circuit switch device according to any one of claims 1 to 4.

  The invention according to claim 7 is the invention according to claim 6, wherein the protection circuit includes the thermal protection circuit switch device disposed between a positive electrode terminal of the secondary battery and the first external terminal. There is an overcharge detection circuit that detects that the secondary battery is overcharged, a switch element that is on / off controlled by a detection signal of the overcharge detection circuit, and the secondary battery is overcharged And a heater for heating the thermal switch element in the thermal protection circuit switch device when the switch element is turned on and energized.

  The invention of claim 8 is characterized in that, in the invention according to claim 7, the overcharge detection circuit, the switch element and the heater constituting the protection circuit are constituted by a semiconductor integrated circuit.

  According to a ninth aspect of the invention, there is provided the semiconductor integrated circuit according to the eighth aspect, wherein a heating body for heating the thermal switch element in the thermal protection circuit switch device is the semiconductor integrated circuit.

  According to the first aspect of the present invention, the second surface side of the frame body is open so that the heating body for heating the thermal switch element can be disposed between the first support member and the second support member. Therefore, after mounting the heating element on the wiring board, the thermal protection switch device can be mounted on the wiring board independently of the mounting of the heating element. it can. For this reason, the assembly of the protection circuit board is facilitated, and the structure of the wiring board is not complicated, so that the downsizing of the protection circuit board can be promoted.

  According to the second aspect of the present invention, since the frame member is provided with the connecting member, the bimetal element can be fixed at an accurate position with respect to the movable contact member. For this reason, a bimetal element can be made to act correctly with respect to a movable contact member, and a circuit can be turned off reliably.

  According to invention of Claim 3, since the recessed part formed in the 2nd surface side of a connection member is made into the open shape which can arrange | position the heating body for heating a thermal switch element, a thermal protection switch apparatus Can be mounted on the wiring board such that the heating element is disposed in the recess on the second surface side of the connecting member. For this reason, positioning of the thermal protection switch device with respect to the heating body is facilitated, and assembly of the protection circuit board is facilitated.

  According to the invention of claim 4, since the cover body that covers the thermal switch element is provided on the first surface side of the frame body, the thermal switch element can be protected from external pressure and dust. For this reason, a heat-sensitive protection switch device with high operational reliability can be realized.

  According to the invention of claim 5, since the frame body is configured by fixing the first support member and the second support member with the wiring board, the frame body can be made robust. For this reason, a heat-sensitive protection switch device with high operational reliability can be realized.

  According to the invention of claim 6, since the protection circuit configured using the thermal protection circuit switch device is provided, the downsizing of the protection circuit board is promoted. For this reason, downsizing of the battery pack is also promoted.

  According to the invention of claim 7, when the secondary battery is excessively charged, the heater is energized and the thermal switch element constituting the thermal protection circuit switch device is heated, so that the charging circuit is reliably shut off. . For this reason, a secondary battery can be protected reliably and a highly reliable battery pack can be realized.

  According to the eighth aspect of the present invention, since the overcharge detection circuit, the switch element, and the heater that constitute the protection circuit are configured by the semiconductor integrated circuit, the protection circuit is miniaturized and the miniaturization of the protection circuit board is further promoted. The For this reason, downsizing of the battery pack is further promoted.

  According to the ninth aspect of the present invention, since the thermal switch element constituting the thermal protection circuit switch device is heated by the semiconductor integrated circuit, the heat generation amount is increased and the thermal switch element is reliably heated as compared with the case of only the heater. The For this reason, a secondary battery can be protected reliably and a highly reliable battery pack can be realized.

  FIG. 13 is a diagram showing a configuration of a thermal protection switch device 4 using a bimetal switch 2 composed of a movable contact member and a bimetal element, for comparison with the thermal protection switch device of the present invention. That is, a thermal protection switch device 4 using a bimetal switch 2 composed of a movable contact member and a bimetal element is inserted in a charge / discharge circuit of a secondary battery, and overcharge detection is detected when an excessive charge current flows through the secondary battery. Based on the detection signal output from the circuit, the heating element 6 generates heat and the bimetal switch 2 is operated to turn off the circuit and to move the movable contact member when an excessive discharge current flows through the secondary battery. The bimetal switch 2 is operated by the Joule heat generated by the contact resistance of the contact to turn off the circuit, thereby preventing excessive charging current and excessive discharging current from flowing through the secondary battery. It is possible.

  According to the protection circuit having such a configuration, it is possible to prevent an excessive charging current and an excessive discharging current flowing in the secondary battery only by providing the overcharge detection circuit, which is compared with the conventional configuration shown in FIG. This not only simplifies the circuit configuration by reducing the number of component parts of the protection circuit, but also simplifies the circuit configuration, thereby reducing the size of the protection circuit board in which each component is arranged on the wiring board. Will be.

  However, since it is necessary to integrate the bimetal switch 2 and the heating body 6 for heating the bimetal switch 2 into the wiring board 8, not only the assembly of the protection circuit board becomes complicated, but also the wiring board 8 When the structure is complicated, there is a limit to downsizing of the protection circuit board, and when the battery pack is configured, downsizing of the battery pack may be hindered. For this reason, the case where the thermal protection switch apparatus of this invention which does not produce this inconvenience is applied to a battery pack is demonstrated below.

  FIG. 1 is an external exploded perspective view for explaining a schematic configuration of a battery pack using a thermal protection switch device according to the present invention. In this figure, the battery pack 10 includes a flat battery storage portion 12, a circuit storage portion 14 fitted to the opening end side of the battery storage portion 12, and the battery storage portion 12 and the circuit storage portion 14. And an intervening insulating spacer 16.

  The battery storage unit 12 includes, for example, an open top case 18 made of a steel plate with nickel plating on the surface, a lithium ion secondary battery, a lithium polymer secondary battery, a nickel hydrogen secondary battery, and a nickel cadmium secondary. A secondary battery 20 such as a battery is accommodated such that the convex positive electrode terminal 22 protrudes from the open end, and is sealed by caulking after the secondary battery 20 is accommodated in the case 18. The negative electrode terminal 23 of the battery 20 is connected to the case 18.

  The circuit housing portion 14 is formed by housing a protection circuit board 26 that forms a protection circuit 40 described later in a case 24 having an open bottom surface made of, for example, a synthetic resin material, and is formed on the bottomed upper surface of the case 24. The first external terminal T1 and the second external terminal T2 corresponding to the positive electrode terminal 22 and the negative electrode terminal 23 of the secondary battery 20 are exposed and disposed in the plurality of window portions 28, and are opposed to each other on the opening surface of the case 24. A connection terminal 30 made of a metal plate extending downward from the edge is provided. The circuit housing portion 14 is combined with the opening end side of the battery housing portion 12 through the insulating spacer 16 in a state where the protection circuit board 26 constituting the protection circuit 40 is housed therein, and the connection terminal 30 is electrically connected to the case 18. The battery pack 10 is configured together with the battery storage unit 12 by being connected to each other.

  FIG. 2 is a circuit diagram showing an example of the electrical configuration of the battery pack 10 shown in FIG. That is, the battery pack 10 includes the first external terminal T1 and the second external terminal T2 that are connected to the secondary battery 20 to a load device such as a charging device (not shown) or a mobile phone, and the secondary battery 20 Between the positive electrode terminal 22 and the negative electrode terminal 23 and the first external terminal T1 and the second external terminal T2, the secondary battery 20 is prevented from flowing an excessive charging current, and an excessive discharge current is prevented from flowing. The protection circuit 40 is connected and configured.

  The protection circuit 40 includes a thermal protection switch device 42 interposed between the positive electrode terminal 22 of the secondary battery 20 and the first external terminal T1, and between the positive electrode terminal 22 and the negative electrode terminal 23 of the secondary battery 20. And an overcharge detection circuit 44 for detecting that the secondary battery 20 is excessively charged due to an excessive charging current flowing through the secondary battery 20, and ON / OFF control by a detection signal of the overcharge detection circuit 44. MOSFET 46 that is a switching element, and a heater 48 that is a heating element connected between the positive electrode terminal 22 and the negative electrode terminal 23 of the secondary battery 20 via the MOSFET 46.

  Here, the thermal protection switch device 42 is configured using a bimetal switch. When the bimetal switch is not heated by the heating body 48, the charge / discharge circuit of the secondary battery 20 is turned on, and the bimetal switch is turned on. Is heated by the heater 48, the charging / discharging circuit of the secondary battery 20 is turned off. A specific configuration of the thermal protection switch device 42 will be described later.

  The overcharge detection circuit 44 includes a comparator 50 and a reference voltage source 52, and the + terminal of the comparator 50 is connected to the positive terminal 22 of the secondary battery 20 and the − terminal is connected to the reference voltage source 52. The output terminal is connected to the gate G of the MOSFET 46. Here, the reference voltage source 52 is set to a voltage value at which it can be determined that the secondary battery 20 has exceeded the fully charged state and has entered an overcharged state in which an excessive charging current flows. The drain D of the MOSFET 46 is connected to the heating body 48, and the source S is connected to the negative terminal 23 of the secondary battery 20.

  FIG. 3 is a cross-sectional view of an essential part for explaining an example of a specific configuration of the thermal protection switch device 42. That is, the thermal protection switch device 42 is configured to be surface-mountable on a wiring board, and the frame body 60 integrally formed of an insulating material such as a synthetic resin or ceramics, a first metal plate or the like is formed. A wiring conductor 62, a second wiring conductor 64 formed on a thin metal plate, a bimetallic switch 66 that is a thermal switch element, and a cover body 68 that covers the bimetallic switch 66 on the surface side of the frame body 60. is there.

  Here, the frame body 60 includes a first support member 70, a second support member 72 disposed to face the first support member 70 at a predetermined interval, and the first support member 70 and the second support member 72. A connecting member 74 is provided that is connected at an intermediate portion between the front surface that is the first surface and the back surface that is the second surface facing the first surface (between the upper and lower surfaces in the drawing). In this frame body 60, the connection member 74 is formed in an intermediate portion between the front and back surfaces of the first support member 70 and the second support member 72, so that the first support member 70 and the second support on the back surface side of the connection member 74. A recess (space) 76 is formed between the members 72, and the recess 76 is opened to the outside so that the bimetal switch 66 can be placed in the recess 76 when the thermal protection switch device 42 is mounted on a wiring board or the like. A heater 48 (FIG. 2), which is a heating body for heating, can be disposed.

  The first wiring conductor 62 is disposed on the first support member 70 on the surface side of the frame body 60 to form a first contact (first connection point) 78, and from the first contact 78 to the first support member 70. The first mounting terminal 80 is configured by extending through the outer surface of the first mounting terminal 80. The first attachment terminal 80 is bent outward at the back surface position of the first support member 70 so as to be flush with the back surface of the first support member 70.

  The second wiring conductor 64 is disposed on the surface of the second support member 72 on the surface side of the frame body 60 to form a second contact (second connection point) 82, and from the second contact 82 to the second support member 72. The second attachment terminal 84 is configured by extending through the outer surface of the second attachment terminal 84. The second attachment terminal 84 is bent outward at the back surface position of the second support member 72 so as to be flush with the back surface of the second support member 72. The second wiring conductor 64 is also extended on the surface of the connecting member 74 so that a bimetal element 88 described later can be easily attached.

  The bimetal switch 66 includes a long movable contact member 86 disposed between the first contact 78 of the first wiring conductor 62 and the second contact 82 of the second wiring conductor 64, and the back surface of the movable contact member 86. And a bimetal element 88 disposed on the surface of the connecting member 74 located on the side.

  Here, the movable contact member 86 has a fixed contact 90 at one end and a movable contact 92 at the other end, and the fixed contact 90 is attached to the second contact 82 of the second support member 72 by spot welding or the like. At the same time, when the movable contact 92 is not subjected to the acting force of the bimetal element 88, the first contact 78 and the second contact 82 are turned on by always contacting the first contact 78 of the first support member 70. When the movable contact 92 receives the acting force of the bimetal element 88, the first contact 78 and the second contact 82 are turned off by separating from the first contact 78 of the first support member 70.

  In addition, the bimetal element 88 has a long shape with a central portion curved toward the movable contact member 86, and one end located on the second support member 72 side is a second wiring conductor on the surface of the connecting member 74 by spot welding or the like. When the bimetal element 88 is heated, the other end located on the first support member 70 side is curved toward the movable contact member 86 side, and the movable contact member is acted upon by the acting force when contacting the movable contact member 86. 86 movable contacts 92 are separated from the first contact 78 of the first support member 70. A protrusion 95 for improving the positional accuracy of the bimetal element 88 is provided on the surface side of the connecting member 74.

  The cover body 68 is for protecting the bimetal switch 66 from external pressure, dust, and the like, and has a structure in which both longitudinal ends of a long insulating plate material are bent toward the first mounting terminal 80 and the second mounting terminal 84 side. The bent end face is fixed to the first attachment terminal 80 and the second attachment terminal 84 by, for example, bonding.

  The thermal protection switch device 42 configured as described above includes the first mounting terminal 80 and the first mounting terminal 80 so that the heater 48 is disposed in the recess 76 of the frame body 60 on the wiring board on which the heater 48 (FIG. 2) is mounted. 2 is mounted on the surface by mounting terminals 84, and the protection circuit 40 using the thermal protection switch device 42 operates as follows.

  That is, when the charging device is connected between the first external terminal T1 and the second external terminal T2 and the secondary battery 20 is charged, the voltage of the reference voltage source 52 until the secondary battery 20 reaches an excessively charged state. Is higher than the voltage of the secondary battery 20, a low signal is output from the comparator 50, the MOSFET 46 is turned off, and the heating body 48 is in a non-energized state. For this reason, the thermal protection switch device 42 is maintained in the ON state, and charging of the secondary battery 20 is continued. In addition, since the charging device includes a protection circuit that stops the charging operation when the secondary battery 20 reaches the full charge, the charging operation is terminated when the fully charged state is reached.

  However, when an excessive charging current flows through the secondary battery 20 due to malfunction due to a failure of the charging device or the like, the voltage of the secondary battery 20 becomes higher than the voltage of the reference voltage source 52. Is output, the MOSFET 46 is turned on, and the heating body 48 is energized, whereby the heating body 48 generates heat.

  As a result, the bimetal element 88 constituting the bimetal switch 66 is heated and curved toward the movable contact member 86, and the movable contact 92 of the movable contact member 86 is separated from the first contact 78 by the acting force of the bimetal element 88. Thus, the circuit in the charged state is turned off, and the supply of the charging current to the secondary battery 20 supplied from the charging device is stopped. Thereby, the secondary battery 20 is effectively prevented from being excessively charged.

  On the other hand, when a load device such as a mobile phone is connected between the first external terminal T1 and the second external terminal T2, and an excessive discharge current flows through the secondary battery 20 due to a failure of the load device, the movable contact member The movable contact member 86 is heated by Joule heat generated by the contact resistance between the movable contact 92 of the 86 and the first contact 78, and the bimetal element 88 is heated by the heated movable contact member 86. As a result, the circuit in the energized state is turned off by moving the movable contact 92 of the movable contact member 86 away from the first contact 78 by the acting force due to the bending of the bimetal element 88, and the load device from the secondary battery 20 is turned off. The power supply to is stopped. This effectively prevents an excessive discharge current from flowing through the secondary battery 20.

  FIG. 4 is a side view of the protection circuit board 26 shown in FIG. 1 in which the protection circuit 40 is configured on the wiring board 96 using the thermal protection switch device 42 configured as described above. In the protection circuit board 26, for example, the heater 48 is fixed to a predetermined position on the surface of the wiring board 96 with a heat resistant adhesive or the like, and then the thermal protection switch device 42 is arranged in the recess 76 so that the heater 48 is disposed. Then, the first mounting terminal 80 and the second mounting terminal 84 are connected to a land (not shown) of the wiring board 96 with a conductive adhesive or the like and surface-mounted, and a circuit portion including the overcharge detection circuit 44 and the MOSFET 46 is a hybrid integrated circuit. The control circuit unit 98 that has been converted into a circuit is connected to a land (not shown) and mounted on the surface.

  Here, the wiring board 96 constituting the protection circuit board 26 has a first mounting electrode 100 and a second mounting electrode 102 for connecting to the positive terminal 22 and the negative terminal 23 of the secondary battery 20 at both ends of the surface. The first external terminal T1 and the second external terminal T2 are disposed on the back surface of the thermal protection switch device 42, the heating body 48, the control circuit unit 98, the first mounting electrode 100, and the second mounting electrode 102. A wiring pattern (not shown) for connecting the first external terminal T1 and the second external terminal T2 is provided.

  The protection circuit board 26 configured as described above is formed as a unit that can be handled by the thermal protection switch device 42 independently of the heater 48, and includes the first support member 70 and the first support member 70 of the thermal protection switch device 42. Since the recess 76 between the two support members 72 is open to communicate with the outside, after mounting the heater 48 on the wiring board 96, the thermal protection switch device 42 is connected to the wiring board 96 independently of the mounting of the heater 48. Can be implemented. This facilitates assembly of the protective circuit board 26 and complicates the structure of the wiring board 96 as compared to the structure shown in FIG. 13 in which the thermal switch element and the heating body are integrated into the wiring board. Therefore, it is possible to promote downsizing of the protection circuit board 26, and thus, it is possible to promote downsizing of the battery pack 10.

  5 shows the arrangement of the protection circuit board 26 with respect to the secondary battery 20 when the battery pack 10 shown in FIG. 1 is configured using the protection circuit board 26 shown in FIG. 4, and the secondary battery 20 and the protection circuit board 26. FIG. 2 is a diagram conceptually showing an electrical connection relationship between the secondary battery 20 and a case 18 in which the secondary battery 20 is stored and a case 24 in which the protective circuit board 26 is stored.

  That is, by fitting a case 24 (not shown) containing the protection circuit board 26 into a case 18 (not shown) containing the secondary battery 20, the side on which the protection circuit board 26 is mounted with the thermal protection switch device 42 and the like. The first mounting electrode 100 of the protection circuit board 26 and the negative electrode terminal 23 of the secondary battery 20 are connected to each other by the connection terminal 30 (FIG. 1), and are arranged so as to face the secondary battery 20. 102 and the positive electrode terminal 22 of the secondary battery 20 are connected by the connection terminal 104, and the battery pack 10 is formed by exposing the first external terminal T1 and the second external terminal T2 to the window portion 28 (FIG. 1) of the case 24. Composed. It is also possible to mold an insulating resin in a gap between the secondary battery 20 and the protection circuit board 26. Thus, when molding insulating resin, it is preferable that the cover body 68 of the thermal protection switch device 42 has a sealed structure.

  6 uses the thermal protection switch device 42 configured as described above, and uses the IC element 110 in which only the thermal protection switch device 42 of the protection circuit 40 is removed as a semiconductor integrated circuit. It is a side view of the protection circuit board 26 configured to be mounted on the substrate 112. For example, the protection circuit board 26 is formed by fixing the IC element 110 to the surface of the wiring board 112 with a heat-resistant adhesive or the like so that the heater 48 faces the bimetal element 88 side of the thermal protection switch device 42. The device 42 is surface-mounted by connecting the first mounting terminal 80 and the second mounting terminal 84 to a land (not shown) of the wiring board 112 with a conductive adhesive or the like so that the IC element 110 is accommodated in the recess 76. It is constituted by.

  Here, the wiring board 112 constituting the protection circuit board 26 has a first attachment electrode 114 and a second attachment electrode 116 for connecting to the positive terminal 22 and the negative terminal 23 of the secondary battery 20 at both ends of the surface. The first external terminal T1 and the second external terminal T2 are disposed on the back surface of the thermal protection switch device 42, the IC element 110, the first mounting electrode 114, the second mounting electrode 116, and the first external terminal. A wiring pattern (not shown) for connecting T1 and the second external terminal T2 is provided.

  The protection circuit board 26 configured as described above is an open state in which the recess 76 between the first support member 70 and the second support member 72 in the thermal protection switch device 42 communicates with the outside, and therefore, the IC including the heater 48. After mounting the element 110 on the wiring board 112, the thermal protection switch device 42 can be mounted on the wiring board 112 independently of the mounting of the IC element 110 including the heater 48. This facilitates assembly of the protective circuit board 26 and complicates the structure of the wiring board 112 as compared to the structure shown in FIG. 13 in which the thermal switch element and the heating body are integrated into the wiring board. Therefore, it is possible to promote downsizing of the protection circuit board 26, and thus, it is possible to promote downsizing of the battery pack 10.

  Further, in this protection circuit board 26, since the IC element 110 is a semiconductor integrated circuit except for the thermal protection switch device 42, the arrangement space for components mounted on the wiring board 112 can be reduced. Further, downsizing of the protection circuit board 26 can be further promoted, and thereby, downsizing of the battery pack 10 can be further promoted. In this case, the IC element 110 including the heater 48 also serves as a heating body for heating the bimetal switch 66. That is, the bimetal switch 66 is heated by the heat generated from the heater 48 and the heat generated from the IC element 110 excluding the heater 48.

  7 shows an arrangement configuration of the protection circuit board 26 with respect to the secondary battery 20 when the battery pack 10 shown in FIG. 1 is configured using the protection circuit board 26 shown in FIG. 6, and the secondary battery 20 and the protection circuit board 26. FIG. 2 is a diagram conceptually showing an electrical connection relationship between the secondary battery 20 and a case 18 in which the secondary battery 20 is stored and a case 24 in which the protective circuit board 26 is stored.

  That is, by fitting a case 24 (not shown) containing the protection circuit board 26 into a case 18 (not shown) containing the secondary battery 20, the side on which the protection circuit board 26 is mounted with the thermal protection switch device 42 and the like. The first mounting electrode 114 of the protection circuit board 26 and the negative electrode terminal 23 of the secondary battery 20 are connected to each other by the connection terminal 30 (FIG. 1), and are disposed so as to face the secondary battery 20. 116 and the positive electrode terminal 22 of the secondary battery 20 are connected by the connection terminal 118, and the battery pack 10 is exposed by exposing the first external terminal T1 and the second external terminal T2 to the window portion 28 (FIG. 1) of the case 24. Composed. It is also possible to mold an insulating resin in a gap between the secondary battery 20 and the protection circuit board 26. Thus, when molding insulating resin, it is preferable that the cover body 68 of the thermal protection switch device 42 has a sealed structure.

  FIG. 8 is a circuit diagram showing another example of the electrical configuration of the battery pack 10 shown in FIG. In this configuration example, a thermal fuse 120 is provided between the positive electrode terminal 22 of the secondary battery 20 and the thermal protection switch device 42 to configure the protection circuit 40, and other configurations are the same as those shown in FIG. It is. For this reason, the detailed description is abbreviate | omitted by providing the same code | symbol about a common structural member. That is, in this configuration example, when the movable contact 92 of the movable contact member 86 constituting the bimetal switch 66 is baked on the first contact 78, the temperature fuse 120 is generated by the generated heat generated in the heater 48 and the movable contact member 86. The circuit is cut off by fusing.

  FIG. 9 is a view showing a battery pack 122 having a structure different from that shown in FIG. 1 configured using the protection circuit board 26 having the circuit configuration shown in FIG. 8 on which the thermal protection switch device 42 is mounted. In this configuration example, the battery pack 122 has a thermal fuse 120 interposed between the positive electrode terminal 22 and the thermal protection switch device 42 of the secondary battery 20 shown in FIG. 2, and has an opening made of an insulating material. The secondary battery 20 is accommodated in the case 126 with the positive terminal 22 facing the opening side, and the protection circuit board 26 is attached to the case 126 in a state where the thermal protection switch device 42 of the protection circuit board 26 is fitted in the opening of the case 126. It is attached and configured.

  The protection circuit board 26 in this embodiment has basically the same configuration as that shown in FIG. 6 except for the mounting configuration of the first external terminal T1 and the second external terminal T2. That is, in this embodiment, the first external terminal T1 is constituted by a metal plate connected to the second mounting terminal 84 of the thermal protection switch device 42 via the metal spacer 128 disposed on the side surface of the wiring board 112. In addition, the second external terminal T2 is attached to the front surface edge of the wiring board 112, and is composed of a metal plate bent at the side surface of the wiring board 112 and extending to the back surface of the wiring board 112, and a thermal fuse. 120 is connected between the positive terminal 22 of the secondary battery 20 and the first wiring conductor 62 of the thermal protection switch device 42, and the negative terminal 23 and the second external terminal T2 of the secondary battery 20 are connected to the metal conductor 130. In this way, the battery pack 122 is configured.

  The battery pack 122 having this configuration is also smaller than the battery pack 122 having the structure shown in FIG. 13 in which the thermal switch element and the heating body are integrally incorporated in the wiring board, similarly to the battery pack 10 shown in FIGS. Since the protective circuit board 26 that has been facilitated is used, downsizing is facilitated and handling becomes easy. As in the case of the configuration examples thus far, it is also possible to mold an insulating resin in the gap between the secondary battery 20 and the protection circuit board 26. Thus, when molding insulating resin, it is preferable that the cover body 68 of the thermal protection switch device 42 has a sealed structure.

  Since the thermal protection switch device 42 according to the present invention has an open shape in which the recess 76 between the first support member 70 and the second support member 72 in the frame body 60 is open to the outside as in the above embodiment, the heater 48 or the IC element 110 may be mounted on the wiring boards 96 and 112, and then the thermal protection switch device 42 may be mounted on the wiring boards 96 and 112 independently of the mounting of the heater 48 or the IC element 110 that is a heating element. it can. This facilitates assembly of the protective circuit board 26 and complicates the structure of the wiring board 96 as compared to the structure shown in FIG. 13 in which the thermal switch element and the heating body are integrated into the wiring board. Therefore, the downsizing of the protection circuit board 26 can be promoted, and thus the downsizing of the battery packs 10 and 122 can be promoted.

  The thermal protection switch device 42 according to the present invention is not limited to the above-described embodiment, and various modifications as described below can be adopted as necessary.

  (1) In the above embodiment, the thermal protection switch device 42 includes the cover body 68, but is not limited thereto. For example, when it is not necessary to protect the bimetal switch 66 from external pressure or dust, the cover body 68 can be removed.

  (2) In the above embodiment, the thermal protection switch device 42 forms the recess 76 between the first support member 70 and the second support member 72 on the back surface side of the connecting member 74 in the frame body 60, and this recess 76 is formed outside. However, the present invention is not limited to this. For example, as shown in FIG. 10, the frame body 60 is configured such that the back surface of the connecting member 74 and the back surfaces of the first support member 70 and the second support member 72 are flush with each other. It is also possible to adopt a configuration in which no components exist between at least the first support member 70 and the second support member 72 on the side.

  In this case, as shown in FIG. 11, the depressed portion 142 is formed on the wiring board 140 on which the thermal protection switch device 42 is mounted, and the heater 48 (or the IC element 110) is arranged on the depressed portion 142. In this state, the thermal protection switch device 42 may be mounted on the wiring board 140 by arranging it so that the first support member 70 and the second support member 72 are opposed to the depression 142. In short, the heater 48 or the IC element 110 which is a heating body for heating the thermal switch element such as the bimetal switch 66 can be disposed on the back side of the frame body 60 between the first support member 70 and the second support member 72. What is necessary is just to be made into the open state.

  (3) In the above embodiment, the thermal protection switch device 42 is generated by the contact resistance between the movable contact 92 and the first contact 78 of the movable contact member 86 when an excessive discharge current flows in the circuit. The bimetal switch 66 is activated by heat, but is not limited thereto. For example, the thermal protection switch device 42 may be operated only when an excessive charging current flows in the circuit.

  (4) In the above embodiment, the thermal protection switch device 42 is configured using the bimetal switch 66 including the movable contact member 86 and the bimetal element 88, but the present invention is not limited to this. For example, the movable contact member 86 can be made of bimetal. In such a case, since the bimetal element 88 is not necessary, the connecting member 74 is not necessarily required.

  (5) In the above embodiment, the thermal protection switch device 42 is configured by using the bimetal switch 66, but is not limited thereto. For example, instead of the bimetal switch 66 which is a thermal switch element, other thermal switch elements such as a polymer-based PTC thermistor element (a positive temperature coefficient thermistor element) whose resistance value suddenly increases when a predetermined temperature is reached are used. You can also. As described above, when an excessive discharge current flows when a PTC thermistor element is used instead of the bimetal switch 66, the PTC thermistor element becomes a high resistance value due to the self-heating of the PTC thermistor element. Can be turned off. In addition, when using a PTC thermistor element, since it is hold | maintained only by connecting the pair of terminals to the 1st contact (1st connection point) 78 and the 2nd contact (2nd connection point) 82, such a thing In some cases, the connecting member 74 is not necessary.

  (6) In the above embodiment, the protection circuit 40 having the configuration shown in FIG. 2 or FIG. 8 is shown as the protection circuit 40 that turns off the charge / discharge circuit when an excessive charging current or excessive discharging current flowing in the secondary battery 20 flows. However, it is not limited to this. For example, a circuit for preventing chattering of the bimetal switch 66 can be added as the protection circuit 40.

  (7) In the above embodiment, the thermal protection switch device 42 is described as being used for the protection circuit 40 that constitutes the battery packs 10 and 122, but is not limited thereto. For example, it goes without saying that it can be used as a protection circuit for electrical components other than the battery packs 10 and 122, for example.

  (8) In the above-described embodiment, the thermal protection switch device 42 can be surface-mounted on the wiring board by bending the first mounting terminal 80 and the second mounting terminal 84 outward, but is not limited thereto. It is not a thing. For example, the first mounting terminal 80 may be bent on the back surface side of the first support member 70 and the second mounting terminal 84 may be bent on the back surface side of the second support member 72 so as to be surface-mounted on the wiring board.

  (9) In the above-described embodiment, the thermal protection switch device 42 is configured such that the first mounting terminal 80 and the second mounting terminal 84 can be surface-mounted, but is not limited thereto. For example, the first mounting terminal 80 and the second mounting terminal 84 may be configured in an axial shape, and inserted into the mounting hole of the wiring board for mounting.

  Since the thermal protection switch device according to the present invention can be mounted on the wiring board independently of the mounting of the heating body, the structure of the wiring board can be simplified and the protection circuit board can be constructed. It will be useful.

It is an external appearance disassembled perspective view which shows schematic structure of the battery pack using the thermal protection switch apparatus which concerns on this invention. It is a circuit diagram which shows an example of the electrical constitution of the battery pack shown in FIG. It is principal part sectional drawing which shows an example of the specific structure of the thermal protection switch apparatus which concerns on this invention. It is a side view of the protection circuit board which comprises a protection circuit on a wiring board using the thermal protection switch apparatus shown in FIG. FIG. 5 is a diagram conceptually showing an arrangement configuration of a protection circuit board with respect to a secondary battery and an electrical connection relationship between the secondary battery and the protection circuit board when a battery pack is configured using the protection circuit board shown in FIG. 4. is there. A protection circuit board using the thermal protection switch device shown in FIG. 3 and using an IC element in which only the thermal protection switch device in the protection circuit is formed as a semiconductor integrated circuit and mounting them on a wiring board FIG. It is a figure which shows notionally the arrangement configuration of the protection circuit board with respect to a secondary battery in the case of comprising a battery pack using the protection circuit board shown in FIG. 6, and the electrical connection relationship between the secondary battery and the protection circuit board. . It is a circuit diagram which shows other excitation of the electrical structure of a battery pack. It is a figure which shows schematic structure of the battery pack of a structure different from FIG. 1 using the thermal protection switch apparatus which concerns on this invention. It is principal part sectional drawing which shows the other example of the specific structure of the thermal protection switch apparatus which concerns on this invention. It is a figure for demonstrating the attachment structure to the wiring board of the thermal protection switch apparatus shown in FIG. It is a circuit diagram which shows an example of the electrical structure of the conventional battery pack. FIG. 3 is a partial view of a protection circuit board configured by incorporating a thermal switch element and a heating body into a wiring board.

Explanation of symbols

10, 122 Battery pack 48 Heater 60 Frame body 62 First wiring conductor 64 Second wiring conductor 66 Bimetal switch (thermal switch element)
68 Cover body 70 First support member 72 Second support member 74 Connection member 78 First contact (contact)
82 Second contact (contact)
80 First mounting terminal (mounting terminal)
84 Second mounting terminal (mounting terminal)
86 Movable contact member 88 Bimetal element

Claims (9)

A thermal protection switch device that turns off the circuit by being heated by a heating body,
A frame body having a first support member and a second support member arranged at a predetermined interval;
A first wiring conductor that is disposed on the first support member on the first surface side of the frame body to form a contact, and that extends from the contact to form a first attachment terminal;
A second wiring conductor that is disposed on the second support member on the first surface side of the frame body to form a contact, and that extends from the contact to form a second attachment terminal;
A thermal switch element that is disposed across the contact points of the first wiring conductor and the second wiring conductor and turns off between the contact points when heated by a heating body,
The frame body connects the first support member and the second support member at an intermediate portion between the first surface and the second surface facing the first surface, and connects the bimetal element to the first surface. A connecting member disposed on the surface side;
The frame body is open so that a heating body for heating the thermal switch element can be disposed on the second surface side between the support members ,
The first attachment terminal is bent outward at the second surface position so as to be flush with the second surface of the first support member;
The thermal protection switch device, wherein the second mounting terminal is bent outward at the position of the second surface so as to be flush with the second surface of the second support member .   The thermal switch element includes a movable contact member disposed between the contact points, and a bimetal element that acts on the movable contact member to turn off the contact points when heated by a heating body. The thermal protection switch device according to claim 1, further comprising:   The frame body is formed with a concave portion on the second surface side of the connecting member by forming the connecting member at an intermediate portion between the first surface and the second surface of the first support member and the second support member. 3. The thermal protection switch device according to claim 2, wherein the concave portion is open so that a heating body for heating the thermal switch element can be disposed.   The thermal protection switch device according to any one of claims 1 to 3, further comprising a cover body that covers the thermal switch element on a first surface side of the frame body.   The thermal protection switch device according to any one of claims 1 to 4, wherein the frame body is configured by fixing a first support member and a second support member with a wiring board. A battery pack having a first external terminal and the second external terminal, and a secondary battery for supplying power to the load device, intended to protect the secondary battery, according to claim 1 to 5 a battery pack characterized by comprising a protection circuit using the heat-sensitive coercive Mamorusu switch device according to any one.   The protection circuit is a device in which the thermal protection circuit switch device is disposed between a positive terminal of the secondary battery and the first external terminal, and detects that the secondary battery is excessively charged. An overcharge detection circuit, a switch element that is on / off controlled by a detection signal of the overcharge detection circuit, and the switch element is turned on and energized when the secondary battery is excessively charged. The battery pack according to claim 6, further comprising a heater for heating the thermal switch element in the thermal protection circuit switch device.   8. The battery pack according to claim 7, wherein the overcharge detection circuit, the switch element, and the heater constituting the protection circuit are constituted by a semiconductor integrated circuit. 9. The battery pack according to claim 8, wherein the heating body for heating the thermal switch element in the thermal protection circuit switch device is the semiconductor integrated circuit.

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