Current blocking device and charge / discharge control circuit

Abstract

The present invention relates to a current blocking device (100) in which a plurality of circuit breakers (1) having different operating temperatures are connected in parallel. A circuit breaker (1) is provided with: a fixed piece (2) having a fixed contact (21); a movable piece (4) having an elastically deformable elastic part (44) and a movable contact (41), the movable piece (4) pressing the movable contact (41) against the fixed contact (21) to contact the fixed contact (21); and a thermal response element (5) that transits the state of the movable piece (4) from a conductive state in which the movable contact (41) is in contact with the fixed contact (21) to a blocked state in which the movable contact (41) is separated from the fixed contact (21) by deforming in accordance with a temperature change.

Description

Technical Field

[0001] The present invention relates to a current interrupting device for interrupting current according to temperature changes. Background Art

[0002] Conventionally, as a device for interrupting current, a circuit breaker is known, which includes a fixed contact, a movable piece, and a thermal response element. The movable piece presses the movable contact to the fixed contact to make it contact the fixed contact, and the thermal response element deforms as the temperature changes, so that the state of the movable piece changes from a conductive state in which the movable contact is in contact with the fixed contact to a blocked state in which the movable contact is separated from the fixed contact (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-079594 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The above-mentioned current blocking device is usually arranged near a heating element such as a secondary battery or a load, and operates according to the temperature rise of the heating element, thereby protecting the secondary battery, etc. In such a circuit including a current blocking device and a secondary battery, if the change in the temperature of the heating element can be detected in detail before the movable piece is transferred from the on state to the blocking state and the current is blocked, it can help control the voltage applied to the load, for example, and can further improve the safety of the secondary battery, etc.

[0008] However, in a current interrupting device composed of a single circuit breaker, it is difficult to detect in detail the temperature of the heating element at a stage before the current is interrupted.

[0009] The present invention has been developed in view of the above actual situation, and a main object of the present invention is to provide a current interruption device capable of detecting in detail the change in temperature of a heating element at a stage before current interruption.

[0010] Solutions for solving the above technical problems

[0011] The present invention is a current blocking device for blocking current, which is formed by connecting a plurality of circuit breakers in parallel.

[0012] The circuit breaker comprises: a fixed piece having a fixed contact; a movable piece having an elastic portion capable of elastic deformation and a movable contact, wherein the movable contact is pressed against the fixed contact to contact the fixed contact; and a thermal response element, which deforms with temperature changes to change the state of the movable piece from a conducting state in which the movable contact contacts the fixed contact to a blocking state in which the movable contact is separated from the fixed contact, wherein the operating temperatures at which the state of the movable piece changes from the conducting state to the blocking state are different in the plurality of circuit breakers.

[0013] Effects of the Invention

[0014] The current blocking device of the present invention includes a plurality of circuit breakers having fixed pieces, movable pieces and thermal response elements and having different operating temperatures. As the temperature of the heating element rises, the state of the movable piece starts to shift from the on state to the blocked state in sequence from the circuit breaker with a low operating temperature. In addition, since the circuit breakers are connected in parallel, the resistance between the two ends of the current blocking device changes as the state of each movable piece shifts, and the current is blocked when the state of the movable pieces of all the circuit breakers shifts to the blocked state. Therefore, by monitoring the change in resistance between the two ends of the current blocking device, the change in the temperature of the heating element in the previous stage when the current is blocked can be detected in detail. Thus, for example, by controlling the input and output of the secondary battery based on the resistance between the two ends of the current blocking device, the safety of the secondary battery and the like can be easily improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a diagram showing a current interrupting device according to one embodiment of the present invention.

[0016] Figure 2 It is shown Figure 1 A perspective view of the structure of a circuit breaker before assembly.

[0017] Figure 3 is shown in the on state Figure 2 A cross-sectional view of a circuit breaker.

[0018] Figure 4 It is shown in the blocking state Figure 2 A cross-sectional view of a circuit breaker.

[0019] Figure 5 It is shown Figure 1 A perspective view of another configuration of a circuit breaker before assembly.

[0020] Figure 6 is shown in the on state Figure 5 A cross-sectional view of a circuit breaker.

[0021] Figure 7 It is shown in the blocking state Figure 5A cross-sectional view of a circuit breaker.

[0022] Figure 8 It is shown Figure 1 Diagram of the initial action of the current-breaking device.

[0023] Fig. 9 Then Figure 8 A diagram showing the operation of the current interrupting device in time series.

[0024] Fig.10 Then Fig. 9 A diagram showing the operation of the current interrupting device in time series.

[0025] Fig.11 Then Fig.10 A diagram showing the operation of the current interrupting device in time series.

[0026] Fig.12 Then Fig.11 A diagram showing the operation of the current interrupting device in which one circuit breaker is restored to the on state in a time series.

[0027] Fig.13 It is shown that Figure 1 Block diagram of a charge and discharge control circuit of a current blocking device. DETAILED DESCRIPTION

[0028] Figure 1 A current interrupting device 100 according to an embodiment of the present invention is shown. The current interrupting device 100 is a device that interrupts current according to temperature changes. The current interrupting device 100 is composed of a plurality of circuit breakers 1 connected in parallel.

[0029] The current interrupting device 100 of this embodiment has terminals 101 and 102 for detecting the resistance between the two ends of the current interrupting device 100. One of the terminals 101 is connected to, for example, a secondary battery pack 201, and the other is connected to, for example, a power supply unit 202 or a load 203 (see below). Fig.13 ).

[0030] Figures 2 to 7 The circuit breaker 1 is shown. The circuit breaker 1 is composed of the following components, etc.: a fixed piece 2 having a fixed contact 21; a movable piece 4 having a movable contact 41 at the top end; a thermal response element 5 that deforms with temperature changes; and a housing 10 that accommodates the fixed piece 2, the movable piece 4, and the thermal response element 5. The housing 10 is composed of a housing body (first housing) 7 and a cover member (second housing) 8 mounted on the upper surface of the housing body 7.

[0031] The fixed piece 2 is formed with a terminal 22 exposed from the housing 10. The movable piece 4 is formed with a terminal 42 exposed from the housing 10. The circuit breakers 1 are connected in parallel by connecting the terminals 22 of each circuit breaker 1 to each other and by connecting the terminals 42 to each other.

[0032] The fixing piece 2 is formed by stamping a plate-shaped metal material mainly composed of copper or the like (in addition, there are metal plates of copper-titanium alloy, zinc white copper, brass, etc.). The fixing piece 2 is embedded in the housing body 7 by insert molding and accommodated in the housing body 7 while the terminal 22 is exposed outside the housing body 7.

[0033] The fixed contact 21 is formed at a position opposite to the movable contact 41 by coating, plating or applying a material with good conductivity such as silver, nickel, nickel-silver alloy, copper-silver alloy, gold-silver alloy, etc., and is exposed from a portion of the opening 73a formed inside the shell body 7.

[0034] A terminal 22 is formed at one end of the fixing piece 2. The terminal 22 protrudes outward from a side wall at an end edge of the housing body 7.

[0035] In the present application, unless otherwise specified, in the fixed sheet 2, the surface on one side where the fixed contact 21 is formed (i.e., Figure 2 In the description, the first surface is defined as the first surface, and the surface on the opposite side is defined as the second surface. When the direction from the fixed contact 21 toward the movable contact 41 is defined as the first direction, and the direction opposite to the first direction is defined as the second direction, the first surface faces the first direction, and the second surface faces the second direction. The same is true for other components, such as the movable piece 4 and the thermal response element 5.

[0036] The movable piece 4 is formed into an arm shape symmetrical with respect to the center line in the longitudinal direction by press working a plate-shaped metal material mainly composed of copper or the like.

[0037] A movable contact 41 is formed at the longitudinal end of the movable piece 4. The movable contact 41 is formed of the same material as the fixed contact 21, and is joined to the distal end of the movable piece 4 by means other than welding, coating, crimping, or the like.

[0038] A terminal 42 is formed at the other end of the movable piece 4 in the longitudinal direction. The terminal 42 protrudes outward from the side wall at the end edge of the case body 7. One of the terminal 22 and the terminal 42 is connected to the terminal 101 of the secondary battery, and the other is connected to the terminal 102.

[0039] The movable piece 4 has a contact portion 43 and an elastic portion 44 between the movable contact 41 and the terminal 42. The contact portion 43 contacts the housing body 7 and the cover member 8 between the terminal 42 and the elastic portion 44. The contact portion 43 has a protrusion 43a protruding in a wing shape toward the short side direction of the movable piece 4. By providing the protrusion 43a, the contact portion 43 is sandwiched by the housing body 7 and the cover member 8 in a wide range and a large area, and the movable piece 4 is firmly fixed relative to the housing 10.

[0040] The elastic portion 44 extends from the abutment portion 43 toward the movable contact 41. The movable piece 4 is cantilever-supported by the housing 10 through the abutment portion 43 at the base end side of the elastic portion 44. In this state, the movable contact 41 formed at the top end of the elastic portion 44 is pressed toward the fixed contact 21 and contacts it by elastic deformation of the elastic portion 44, so that the fixed piece 2 and the movable piece 4 can be energized.

[0041] The movable piece 4 is bent or folded at the elastic portion 44 by stamping. There is no particular limitation on the degree of bending or folding as long as the thermal response element 5 can be accommodated, and it can be appropriately set in consideration of the elastic force at the operating temperature and the recovery temperature, the pressing force of the movable contact 41, etc. In addition, a pair of protrusions 44a and 44b are formed on the second surface of the elastic portion 44, which are opposite to the thermal response element 5. The protrusion 44a protrudes toward the thermal response element 5 on the base end side, and abuts against the thermal response element 5 in the blocked state. The protrusion 44b protrudes toward the thermal response element 5 at the top end side (i.e., the movable contact 41 side) compared to the protrusion 44a, and abuts against the thermal response element 5 in the blocked state. When the thermal response element 5 is deformed due to overheating, the thermal response element 5 abuts against the protrusions 44a and 44b, and the deformation of the thermal response element 5 is transmitted to the elastic portion 44 via the protrusions 44a and 44b, and the top end of the movable piece 4 is pushed up (refer to Figure 4 ).

[0042] The thermal response element 5 transfers the state of the movable piece 4 from the conductive state in which the movable contact 41 is in contact with the fixed contact 21 to the blocked state in which the movable contact 41 is separated from the fixed contact 21. The thermal response element 5 forms an initial shape with a curved cross section in an arc shape, and is formed into a plate shape by stacking thin plate materials with different thermal expansion coefficients. If the operating temperature is reached due to overheating, the curved shape of the thermal response element 5 is reversed with the snap motion, and is restored when it is lower than the recovery temperature due to cooling. The initial shape of the thermal response element 5 can be formed by stamping. As long as the elastic part 44 of the movable piece 4 is pushed up by the reverse warping action of the thermal response element 5 at the desired temperature, and is restored due to the elastic force of the elastic part 44, the material and shape of the thermal response element 5 are not particularly limited, but from the perspective of productivity and the efficiency of the reverse warping action, it is preferably rectangular.

[0043] As the material of the thermal response element 5, a material formed by laminating two plate-shaped metal materials with different thermal expansion coefficients composed of various alloys such as zinc white copper, brass, and stainless steel can be used in combination according to the required conditions. For example, as a material of the thermal response element 5 that can obtain a stable operating temperature and recovery temperature, it is preferably a material formed by combining a copper-nickel-manganese alloy on the high expansion side and an iron-nickel alloy on the low expansion side. In addition, as a further preferred material from the viewpoint of chemical stability, a material formed by combining an iron-nickel-chromium alloy on the high expansion side and an iron-nickel alloy on the low expansion side can be cited. In addition, as a further preferred material from the viewpoint of chemical stability and processability, a material formed by combining an iron-nickel-chromium alloy on the high expansion side and an iron-nickel-cobalt alloy on the low expansion side can be cited.

[0044] The operating temperature of the thermal responsive element 5 alone depends on the thermal expansion coefficient and thickness of the metal constituting the thermal responsive element 5, the curvature of the thermal responsive element 5, etc. Therefore, by appropriately changing these parameters, a thermal responsive element 5 with a desired operating temperature can be obtained.

[0045] The housing body 7 and the cover member 8 constituting the housing 10 are formed of thermoplastic resins such as flame-retardant polyamide, polyphenylene sulfide (PPS) with excellent heat resistance, liquid crystal polymer (LCP), polybutylene terephthalate (PBT), etc. If the properties equal to or better than those of the above resins can be obtained, materials other than resins may also be used.

[0046] A recessed portion 73 is formed in the housing body 7 as an internal space for accommodating the movable piece 4, the thermal response element 5, etc. The recessed portion 73 has openings 73a and 73b for accommodating the movable piece 4 and an opening 73c for accommodating the movable piece 4 and the thermal response element 5, etc. In addition, the end edges of the movable piece 4 and the thermal response element 5 assembled in the housing body 7 are respectively abutted by the frame formed inside the recessed portion 73, and are guided when the thermal response element 5 is warped.

[0047] A metal plate mainly composed of copper or stainless steel may be embedded in the cover member 8 by insert molding. The metal plate appropriately contacts the first surface of the movable piece 4, thereby restricting the movement of the movable piece 4, improving the rigidity and strength of the cover member 8 and even the housing 10 as a frame, and contributing to the miniaturization of the circuit breaker 1.

[0048] like Figure 2 , 5As shown, the cover member 8 is mounted on the housing body 7 in a manner of blocking the openings 73a, 73b, 73c, etc. of the housing body 7, and the housing body 7 accommodates the fixed piece 2 (fixed contact 21), the movable piece 4 (movable contact 41, elastic portion 44), the thermal response element 5, etc. The housing body 7 and the cover member 8 are joined by, for example, ultrasonic welding. Thus, the circuit breaker 1 is assembled in a state where the terminals 22 and 42 are exposed.

[0049] Figure 3 , 4 6 and 7 schematically show the operation of the circuit breaker 1 . Figure 3 and 6 The operation of the circuit breaker 1 in a normal charging or discharging state is shown. In a normal charging or discharging state, the thermal response element 5 maintains the initial shape before the reverse warping. The movable contact 41 is pressed to the fixed contact 21 side by the elastic portion 44, whereby the movable contact 41 contacts the fixed contact 21, and the fixed piece 2 and the movable piece 4 of the circuit breaker 1 become conductive.

[0050] like Figure 3 and 6 As shown, the thermal response element 5 may be separated from the protrusions 44a and 44b of the movable piece 4 in the conductive state. Thus, the contact pressure between the movable contact 41 and the fixed contact 21 is increased, and the contact resistance between the two is reduced.

[0051] Figure 4 and 7 The operation of the circuit breaker 1 in an overcharge state or abnormal state is shown. When the temperature reaches a high temperature due to overcharge or abnormality, the thermal response element 5 reaching the operating temperature is reversed and contacts the elastic portion 44 of the movable piece 4, and the elastic portion 44 is pushed up to separate the fixed contact 21 from the movable contact 41. At this time, the current flowing between the fixed contact 21 and the movable contact 41 is blocked.

[0052] When the overcharge state is released or the abnormal state is eliminated, the thermal response element 5 returns to the recovery temperature and recovers to the original initial shape. Then, due to the elastic force of the elastic part 44 of the movable piece 4, the movable contact 41 contacts the fixed contact 21 again, and the circuit blocking state is released and restored to Figure 3 and Figure 6 The on-state is shown.

[0053] like Figure 1 As shown, the current interrupting device 100 of the present invention includes a plurality of (three in the figure) circuit breakers 1 having different operating temperatures. The operating temperature of each circuit breaker 1 depends on the operating temperature and elastic modulus of the thermal response element 5 alone, and the elastic modulus of the movable piece 4. Therefore, for example, by changing the material and shape of the thermal response element 5, the operating temperature of each circuit breaker 1 can be adjusted.

[0054] Since the current blocking device 100 includes a plurality of circuit breakers 1 with different operating temperatures, as the temperature of the heating element rises, the state of the movable piece 4 changes from the on state to the off state, starting from the circuit breaker 1 with the lower operating temperature. Furthermore, since each circuit breaker 1 is connected in parallel, the resistance between the two ends of the current blocking device 100 changes as the state of each movable piece 4 changes. When the state of the movable pieces 4 of all circuit breakers 1 changes to the off state, the current is blocked. Therefore, by monitoring the change of the resistance between the two ends of the current blocking device 100, the change of the temperature of the heating element in the previous stage of the current being blocked can be detected in detail. Therefore, for example, by controlling the input and output of the secondary battery based on the resistance between the two ends of the current blocking device 100, the safety of the secondary battery and the like can be easily improved.

[0055] The resistance between both ends of the current-interrupting device 100 is calculated based on, for example, the potential difference between the terminals 101 and 102 and the current flowing through the current-interrupting device 100 .

[0056] It is preferred that the resistance between the two ends of at least one circuit breaker 1 in the on state is different from the resistance between the two ends of the other circuit breakers 1 in the on state. The resistance between the two ends of each circuit breaker 1 in the on state is the sum of the on resistance of the fixed piece 2 and the movable piece 4 and the contact resistance between the fixed contact 21 and the movable contact 41. The resistance between the two ends of at least one circuit breaker 1 in the on state is different from the resistance between the two ends of the other circuit breakers 1 in the on state, thereby making it easy to identify the circuit breaker 1 in which the state of the movable piece 4 is transferred from the on state to the blocking state, thereby enabling detailed detection of the change in the temperature of the heating element.

[0057] The resistance between the two ends of each circuit breaker 1 in the on state may be different from each other. The resistance between the two ends of each circuit breaker 1 in the on state is different from each other, thereby determining the circuit breaker 1 in which the state of the movable piece 4 is transferred from the on state to the off state, thereby being able to detect the change in the temperature of the heating element in detail.

[0058] In the current-breaking device 100, the circuit breaker 1 preferably includes one or more first circuit breakers 1A. Figure 1 , a current breaking device 100 including one first circuit breaker 1A is shown.

[0059] Figures 2 to 4 The first circuit breaker 1A is shown in FIG. The first circuit breaker 1A includes a PTC (Positive Temperature Coefficient) thermistor 6 for conducting the stator 2 and the thermally responsive element 5 , in addition to the stator 2 , the movable piece 4 , the thermally responsive element 5 , and the housing 10 .

[0060] When the movable piece 4 is in the blocking state, the PTC thermistor 6 makes the fixed piece 2 and the movable piece 4 conduct. The PTC thermistor 6 is arranged between the fixed piece 2 and the thermal response element 5. That is, the support portion 23 of the fixed piece 2 clamps the PTC thermistor 6 and is located directly below the thermal response element 5. When the energization of the fixed piece 2 and the movable piece 4 is blocked due to the reverse warping action of the thermal response element 5, the current flowing to the PTC thermistor 6 increases. As long as the PTC thermistor 6 is a positive characteristic thermistor whose resistance value increases with the increase of temperature, thereby limiting the current, the type can be selected according to the needs of the operating current, operating voltage, operating temperature, recovery temperature, etc., and its material and shape are not particularly limited as long as these characteristics are not damaged. In this embodiment, a ceramic sintered body containing barium titanate, strontium titanate, or calcium titanate is used. In addition to the ceramic sintered body, a so-called polymer PTC in which conductive particles such as carbon are contained in the polymer can also be used.

[0061] exist Figure 4 In the first circuit breaker 1A shown in the blocking state, the thermal response element 5 is in contact with the movable piece 4, so that a small leakage current flows through the thermal response element 5 and the PTC thermistor 6. That is, the PTC thermistor 6 makes the fixed piece 2 and the movable piece 4 conductive via the thermal response element 5 that transfers the movable piece 4 to the blocking state. As long as such a leakage current flows, the PTC thermistor 6 continues to generate heat, and the thermal response element 5 maintains the reverse warping state, and the resistance value increases sharply, so the current does not flow through the path between the fixed contact 21 and the movable contact 41, and only the above-mentioned small leakage current exists (constituting a self-holding circuit). This leakage current can be used for other functions of the circuit including the current blocking device 100.

[0062] In the first circuit breaker 1A, when the movable contact 41 is separated from the fixed contact 21, the leakage current flows between the fixed piece 2 and the movable piece 4 via the thermal response element 5 and the PTC thermistor 6. Therefore, arc discharge is suppressed between the fixed contact 21 and the movable contact 41. Therefore, by configuring the plurality of circuit breakers 1 constituting the current interrupting device 100 to include one or more first circuit breakers 1A, arc discharge is suppressed from occurring inside the current interrupting device 100, and the safety of the current interrupting device 100 is improved.

[0063] In the current-breaking device 100, the circuit breaker 1 may include one or more second circuit breakers 1B. When the current-breaking device 100 includes one first circuit breaker 1A, the current-breaking device 100 further includes one or more second circuit breakers 1B. When the current-breaking device 100 includes one second circuit breaker 1B, the current-breaking device 100 further includes one or more first circuit breakers 1A. Figure 1, a current breaking device 100 including two second circuit breakers 1B is shown.

[0064] Figures 5 to 7 The second circuit breaker 1B is shown. The second circuit breaker 1B is composed of the above-mentioned fixed piece 2, movable piece 4, thermal response element 5, housing 10, etc., and does not have the PTC thermistor 6 included in the first circuit breaker 1A. The resistance of the second circuit breaker 1B in the interrupting state is substantially infinite.

[0065] In the area of ​​the second circuit breaker 1B where the PTC thermistor 6 is arranged in the first circuit breaker 1A, the resin bulges that constitutes the housing body, and the fixing piece 2 and the thermal response element 5 are insulated from each other. Such a second circuit breaker 1B is cheaper than the first circuit breaker 1A having the PTC thermistor 6. Therefore, by including the second circuit breaker 1B, the manufacturing cost of the current breaking device 100 can be suppressed. Furthermore, by including a plurality of second circuit breakers 1B, the manufacturing cost of the current breaking device 100 can be suppressed.

[0066] Figure 1 The current-breaking device 100 shown has a single first circuit breaker 1A and two second circuit breakers 1B. Such a current-breaking device 100 can suppress the manufacturing cost and suppress arc discharge during operation. In addition, the deformation of the circuit breaker 1 constituting the current-breaking device 100 is not limited to the combination of a single first circuit breaker 1A and two second circuit breakers 1B. For example, the current-breaking device 100 of the present invention can be composed of a combination of a single first circuit breaker 1A and a single second circuit breaker 1B, or can be composed of a plurality of first circuit breakers 1A. In addition, the current-breaking device 100 of the present invention can also be composed of a combination of a single or a plurality of first circuit breakers 1A and more than three second circuit breakers 1B. In this case, by constituting the current-breaking device 100 with a larger number of second circuit breakers 1B than the number of first circuit breakers 1A, the manufacturing cost of the current-breaking device 100 can be suppressed. In addition, in particular, in applications requiring low manufacturing costs, the current-breaking device 100 can also be composed of only a plurality of second circuit breakers 1B.

[0067] Figures 8 to 11The operation of the current breaking device 100 including the first circuit breaker 1A and the second circuit breakers 1B1 and 1B2 when the temperature of the current breaking device 100 rises is shown in a time series. Here, the operating temperature of the second circuit breaker 1B1 is set to T1, the operating temperature of the second circuit breaker 1B2 is set to T2, and the operating temperature of the first circuit breaker 1A is set to T3, and it is set that T1<T2<T3. In addition, the resistance between the two ends of the second circuit breaker 1B1 in the on state is set to R1, the resistance between the two ends of the second circuit breaker 1B2 in the on state is set to R2, the resistance between the two ends of the first circuit breaker 1A in the on state is set to R3, and the resistance between the two ends of the first circuit breaker 1A in the blocked state is set to R0.

[0068] In the following, it is assumed that the temperature difference between the first circuit breaker 1A and the second circuit breakers 1B1 and 1B2 is small, and the temperatures of the first circuit breaker 1A and the second circuit breakers 1B1 and 1B2 are substantially equal to the temperature of the heating element.

[0069] like Figure 8 As shown, in the initial state where the temperature of the heating element is lower than T1, the first circuit breaker 1A and the second circuit breakers 1B1 and 1B2 all maintain the on state, and the resistance RR1 between the two ends of the current interrupting device 100 is represented by the combined resistance of the first circuit breaker 1A and the second circuit breakers 1B1 and 1B2.

[0070] like Fig. 9 As shown, when the temperature of the heating element reaches T1, the second circuit breaker 1B1 is switched to the interrupting state, and the resistance RR2 between both ends of the current interrupting device 100 is represented by the combined resistance of the first circuit breaker 1A and the second circuit breaker 1B2.

[0071] like Fig.10 As shown, when the temperature of the heating element reaches T2, the second circuit breaker 1B2 is switched to the interrupting state, and the resistance RR3 between both ends of the current interrupting device 100 is represented by the resistance of the first circuit breaker 1A.

[0072] Then, if Fig.11 As shown, when the temperature of the heating element reaches T3, the first circuit breaker 1A is transferred to the blocking state, and the resistance RR4 between the two ends of the current blocking device 100 is represented by the resistance R0 in the blocking state of the first circuit breaker 1A. In addition, in the current blocking device 100, when all the circuit breakers 1 are composed of the second circuit breaker 1B that does not include the PTC thermistor 6, the resistance RR4 becomes infinite.

[0073] like Figures 8 to 11 As shown, the resistance between both ends of the current interrupting device 100 varies according to the temperature of the heating element. Therefore, by monitoring the resistance between both ends of the current interrupting device 100, the temperature of the heating element can be known.

[0074] Generally, the resistance of each circuit breaker 1 is extremely small when the movable piece 4 is in the on state, and the resistance of each circuit breaker 1 is extremely large when the movable piece 4 is in the off state. Therefore, the change in resistance between the two ends of the current interrupting device 100 when any circuit breaker 1 is switched to the on state is not so large. Therefore, in this embodiment, by setting the resistance between the two ends of each circuit breaker in the on state as follows, the change in resistance between the two ends of the current interrupting device 100 is increased, and the detection accuracy of the operation of each circuit breaker is improved.

[0075] In the current-breaking device 100, preferably, the resistance R3 between the two ends of the first circuit breaker 1A in the on state is larger than the resistance R1 between the two ends of the second circuit breaker 1B1 in the on state, and the resistance R2 between the two ends of the second circuit breaker 1B2 in the on state. That is, preferably, the resistance between the two ends of the first circuit breaker 1A in the on state is larger than the resistance between the two ends of each second circuit breaker 1B in the on state. In such a current-breaking device 100, it is possible to easily improve the detection accuracy of the operation of each second circuit breaker 1B. In addition, the resistance between the two ends of each second circuit breaker 1B in the on state is smaller than the resistance between the two ends of the first circuit breaker 1A in the on state, and therefore, in Figure 8 The initial state shown in Fig. 9 When a portion of the second circuit breaker 1B is in operation as shown, the resistance value of the current interrupting device 100 is suppressed, thereby increasing the charge and discharge current. In addition, in an embodiment in which the second circuit breaker 1B is composed of only a single second circuit breaker 1B1, it is preferred that the resistance R3 between the two ends of the first circuit breaker 1A in the on state is greater than the resistance R1 between the two ends of the second circuit breaker 1B1 in the on state.

[0076] In the current-breaking device 100, the resistance between both ends of the first circuit breaker 1A in the on state may be greater than the resistance between both ends of at least one second circuit breaker 1B (for example, the second circuit breaker 1B1) in the on state. In such a current-breaking device 100, the detection accuracy of the operation of the second circuit breaker 1B1 can be easily improved. Figure 8 In the initial state shown, the resistance value of the current interrupting device 100 is suppressed, so that the charge and discharge current can be increased.

[0077] Furthermore, generally, in a current interrupting device 100 including a plurality of circuit breakers 1, it is preferred that the resistance between both ends of the circuit breaker 1 having the highest operating temperature in the on state is greater than the resistance between both ends of the other circuit breakers 1 in the on state. In such a current interrupting device 100, it is also possible to easily improve the detection accuracy of the operation of the other circuit breakers. Furthermore, since the resistance between both ends of the other circuit breakers 1 in the on state is less than the resistance between both ends of the circuit breaker 1 having the highest operating temperature in the on state, Figure 8 The initial state shown in Fig. 9 In the state where a part of the circuit breaker 1 is operated as shown, the resistance value of the current interrupting device 100 is suppressed, so that the charge and discharge current can be increased.

[0078] In the current-breaking device 100, preferably, the resistance R1 between the two ends of the second circuit breaker 1B1 in the on state is smaller than the resistance R2 between the two ends of the second circuit breaker 1B2 in the on state. That is, preferably, the resistance between the two ends of the second circuit breaker 1B with the lowest operating temperature among the plurality of second circuit breakers 1B in the on state is smaller than the resistance between the two ends of the other second circuit breakers 1B in the on state. In such a current-breaking device 100, it is possible to easily improve the detection accuracy of the operation of the other second circuit breakers 1B after the operation of the second circuit breaker 1B with the lowest operating temperature. In addition, in Figure 8 In the initial state shown, the resistance value of the current interrupting device 100 is suppressed, so the charge and discharge current can be increased.

[0079] Furthermore, generally, in a current interrupting device 100 including a plurality of circuit breakers 1, it is preferred that the resistance between both ends of a circuit breaker 1 having the lowest operating temperature in the on state is smaller than the resistance between both ends of other circuit breakers 1 in the on state. In such a current interrupting device 100, it is possible to easily improve the detection accuracy of the operation of other circuit breakers 1. Figure 8 In the initial state shown, the resistance value of the current interrupting device 100 is suppressed, so that the charge and discharge current can be increased.

[0080] In the current-breaking device 100, preferably, the resistance R1 between the two ends of the second circuit breaker 1B1 in the on state is smaller than the combined resistance (RR2) between the two ends of the second circuit breaker 1B2 and the first circuit breaker 1A in the on state. That is, preferably, the resistance between the two ends of the second circuit breaker 1B with the lowest operating temperature among the plurality of second circuit breakers 1B in the on state is smaller than the combined resistance between the two ends of the other circuit breakers 1 in the on state. In such a current-breaking device 100, the detection accuracy of the operation of the other second circuit breakers 1B after the operation of the second circuit breaker 1B with the lowest operating temperature can be further improved. In addition, in Figure 8 In the initial state shown, the resistance value of the current interrupting device 100 is suppressed, so the charge and discharge current can be increased.

[0081] Furthermore, generally, in a current interrupting device 100 including a plurality of circuit breakers 1, it is preferred that the resistance between both ends of the circuit breaker 1 having the lowest operating temperature in the on state is smaller than the combined resistance between both ends of the other circuit breakers 1 in the on state. In such a current interrupting device 100, it is possible to further improve the detection accuracy of the operation of the other circuit breakers 1 after the operation of the circuit breaker 1 having the lowest operating temperature. Figure 8 In the initial state shown, the resistance value of the current interrupting device 100 is suppressed, so the charge and discharge current can be increased.

[0082] In the current-breaking device 100, the resistance between both ends of the second circuit breaker 1B1 in the on state is preferably 2% to 201% of the combined resistance between both ends of the second circuit breaker 1B2 and the first circuit breaker 1A in the on state. That is, the resistance between both ends of the second circuit breaker 1B with the lowest operating temperature among the plurality of second circuit breakers 1B in the on state is preferably 2% to 201% of the combined resistance between both ends of the other circuit breakers 1 in the on state. The resistance between both ends of the second circuit breaker 1B with the lowest operating temperature in the on state is 2% or more of the combined resistance between both ends of the other circuit breakers 1 in the on state, thereby further improving the detection accuracy of the operation of the second circuit breaker 1B with the lowest operating temperature. The resistance between the two ends of the second circuit breaker 1B with the lowest operating temperature in the on state is less than 200% of the combined resistance between the two ends of the other circuit breakers 1 in the on state, thereby easily improving the detection accuracy of the operation of the other second circuit breakers 1B after the operation of the second circuit breaker 1B with the lowest operating temperature.

[0083] Furthermore, in general, in the current interrupting device 100 including a plurality of circuit breakers 1, it is preferred that the resistance between both ends of the circuit breaker 1 having the lowest operating temperature in the on state of the plurality of circuit breakers 1 is 2% to 201% of the combined resistance between both ends of the other circuit breakers 1 in the on state. Thus, the detection accuracy of the operation of the circuit breaker 1 having the lowest operating temperature can be further improved, and the detection accuracy of the operation of the other circuit breakers 1 after the operation of the circuit breaker 1 having the lowest operating temperature can be easily improved.

[0084] When the discharge or charge of the secondary battery pack 201 is stopped by the operation of the current interrupting device 100 and the temperature of the heating element is lowered, the temperature of each circuit breaker 1 is also lowered, so that each circuit breaker 1 is Figure 4 Or the blocking state shown in 7 is restored to Figure 3The temperature at which each circuit breaker 1 is restored from the blocking state to the conducting state is set as the recovery temperature. The recovery temperature is a temperature lower than the operating temperature and is set for each circuit breaker 1. The recovery temperature is usually related to the operating temperature, but can be set independently of the operating temperature, for example, depending on the curvature and elastic modulus of the thermal response element 5 and the elastic modulus of the movable piece 4.

[0085] Fig.12 The temperature of the heating element is shown as Fig.11 The state shown is reduced, and the circuit breaker 1Z having the highest recovery temperature among the plurality of circuit breakers 1 is the current breaking device 100 that recovers from the blocking state to the conducting state.

[0086] In the current interrupting device 100 including a plurality of circuit breakers 1, the circuit breaker 1Z with the highest recovery temperature is restored first. If it is assumed that the circuit breaker 1Z with the highest recovery temperature is the second circuit breaker 1B that does not include the PTC thermistor 6, then with the recovery of the second circuit breaker 1B, the discharge or charge of the secondary battery pack 201 is restarted. With this, the heating element heats up again, and when the heating element reaches the operating temperature of the second circuit breaker 1B, the current interrupting device 100 is transferred to the operating temperature again. Fig.11 Such a slow vibration (chattering) action is repeated until the power stored in the secondary battery pack 201 is substantially exhausted.

[0087] Therefore, in the current interrupting device 100, it is preferable that the circuit breaker 1Z having the highest recovery temperature among the plurality of circuit breakers 1 is the first circuit breaker 1A. With such a configuration, the current interrupting device 100 maintains the interrupting state until the power stored in the secondary battery pack 201 is consumed by the PTC thermistor 6 of the first circuit breaker 1A and is substantially exhausted, and the temperature of the heating element decreases to the recovery temperature of the first circuit breaker 1A. As a result, the above-mentioned vibration action is suppressed.

[0088] In the embodiment in which the circuit breaker 1Z having the highest recovery temperature is the first circuit breaker 1A, the number of second circuit breakers 1B included in the plurality of circuit breakers 1 and having an operating temperature higher than that of the first circuit breaker 1A may be 1 or less. Since the design and manufacture of such second circuit breakers 1B are difficult, the design and manufacture of the current interrupting device 100 are facilitated by reducing the number of second circuit breakers 1B.

[0089] In the embodiment where the circuit breaker 1Z having the highest recovery temperature is the first circuit breaker 1A, the plurality of circuit breakers 1 may include a circuit breaker 1 having an operating temperature lower than the operating temperature of the first circuit breaker 1A having the highest recovery temperature. In this case, the circuit breaker 1 having an operating temperature lower than the operating temperature of the first circuit breaker 1A having the highest recovery temperature may be the first circuit breaker 1A or the second circuit breaker 1B. Such a circuit breaker 1 is easy to design and manufacture, and thus the current interrupting device 100 is also easy to design and manufacture.

[0090] In the current interrupting device 100, a plurality of circuit breakers 1 may also be composed of the same fixed piece 2 and the same movable piece 4. "The same fixed piece" means a fixed piece formed of substantially the same material and size. As a tolerance in the process, as long as it is within the permissible range, no higher precision is required. Therefore, for example, fixed pieces with equal on-resistance as a single component are the same fixed pieces. The same is true for "the same movable piece". In addition, in this case, in each circuit breaker 1, the contact resistance of the fixed contact 21 and the movable contact 41 may be different from each other.

[0091] In such a current-breaking device 100 , components such as the movable piece 4 and the thermally responsive element 5 constituting each circuit breaker 1 can be made common, and the cost of the current-breaking device 100 can be reduced.

[0092] Fig.13 The charge and discharge control circuit 200 including the current interruption device 100 is shown. The charge and discharge control circuit 200 includes the current interruption device 100, a secondary battery pack 201, a power supply unit 202, a load 203, and a control unit 204.

[0093] The secondary battery pack 201 is connected in series with respect to the current interrupting device 100. The power supply unit 202 supplies DC power for charging the secondary battery pack 201. The load 203 receives the supply of DC power from the secondary battery pack 201. In the charge and discharge control circuit 200 of the present embodiment, both the power supply unit 202 and the load 203 are connected to the secondary battery pack 201, but either one may be omitted. That is, the charge and discharge control circuit 200 includes at least one of the power supply unit 202 and the load 203.

[0094] The secondary battery pack 201 has internal resistance and generates heat during charging or discharging. Therefore, in the charge and discharge control circuit 200, the secondary battery pack 201 becomes a heat generating body, and the current interruption device 100 is configured to easily transfer the heat of the secondary battery pack 201. It is particularly preferred that the plurality of circuit breakers 1 constituting the current interruption device 100 are arranged adjacent to the secondary battery pack 201. In a mode in which a heat conductor is provided to transfer the heat generated by the secondary battery pack 201, the plurality of circuit breakers 1 may also be arranged adjacent to the heat conductor.

[0095] The control unit 204 controls the charging current from the power supply unit 202 or the discharging current flowing to the load 203. The control unit 204 is connected to the terminals 101 and 102 of the current interrupting device 100. Thus, the control unit 204 can detect the resistance between both ends of the current interrupting device 100.

[0096] The control unit 204 detects the resistance between both ends of the current interrupting device 100 to obtain the temperature of the secondary battery pack 201, which is the heating element. Then, the control unit 204 controls the charging current from the power supply unit 202 or the discharging current to the load 203 according to the temperature of the secondary battery pack 201.

[0097] That is, the control unit 204 controls the charging current from the power supply unit 202 or the discharging current to the load 203 based on the resistance between the two terminals of the current interrupting device 100. For example, when the resistance between the two terminals of the current interrupting device 100 increases from RR1 to RR2, the control unit 204 controls the power supply unit 202 or the load 203 so that the charging current or the discharging current decreases. As a result, the temperature rise of the secondary battery pack 201 is suppressed.

[0098] When the resistance across the current interrupting device 100 further increases from RR2 to RR3, the control unit 204 controls the power supply unit 202 or the load 203 so that the charging current or the discharging current further decreases. Thus, the temperature rise of the secondary battery pack 201 is further suppressed. When the resistance across the current interrupting device 100 increases from RR3 to RR4, the control unit 204 also stops the operation of the power supply unit 202 or the load 203 through such control.

[0099] In this way, the operation of the power supply unit 202 or the load 203 is efficiently controlled by the control unit 204 controlling the power supply unit 202 or the load 203 in stages based on the resistance between both ends of the current interrupting device 100 .

[0100] The above describes the current interruption device 100 of the present invention in detail, but the present invention is not limited to the above specific embodiments and can be implemented in various ways. That is, the current interruption device 100 of the present invention can at least be: a current interruption device 100 that interrupts current according to temperature changes, which is formed by connecting multiple circuit breakers 1 in parallel, wherein the circuit breaker 1 has: a fixed piece 2, which has a fixed contact 21; a movable piece 4, which has an elastic part 44 that can be elastically deformed and a movable contact 41, and the movable contact 41 is pressed to the fixed contact 21 to contact the fixed contact 21; a thermal response element 5, which deforms with temperature changes to change the state of the movable piece 4 from the conductive state in which the movable contact 41 contacts the fixed contact 21 to the blocked state in which the movable contact 41 is separated from the fixed contact 21, and the operating temperature of the movable piece 4 changing from the conductive state to the blocked state is different in the multiple circuit breakers 1.

[0101] [Notes]

[0102] The present invention includes the following aspects.

[0103] [Present invention 1]

[0104] A current interrupting device is a current interrupting device that interrupts current and is composed of multiple circuit breakers connected in parallel.

[0105] The circuit breaker comprises: a fixed piece having a fixed contact; a movable piece having an elastic portion capable of elastic deformation and a movable contact, wherein the movable contact is pressed against the fixed contact to contact the fixed contact; and a thermal response element, which deforms with temperature changes to change the state of the movable piece from a conducting state in which the movable contact contacts the fixed contact to a blocking state in which the movable contact is separated from the fixed contact, wherein the operating temperatures at which the state of the movable piece changes from the conducting state to the blocking state are different in the plurality of circuit breakers.

[0106] [Present invention 2]

[0107] In the current interrupting device according to the first aspect of the present invention, the resistance between both ends of at least one of the circuit breakers in the on state is different from the resistance between both ends of the other circuit breakers in the on state.

[0108] [Present invention 3]

[0109] In the current interrupting device according to the second aspect of the present invention, among the plurality of circuit breakers, the circuit breaker having the highest operating temperature has a resistance between both ends in the on state that is greater than the resistance between both ends in the other circuit breakers in the on state.

[0110] [Present invention 4]

[0111] In the current interrupting device according to the second aspect of the present invention, among the plurality of circuit breakers, the circuit breaker having the lowest operating temperature has a resistance between both ends in the on state that is smaller than the resistance between both ends of the other circuit breakers in the on state.

[0112] [Present invention 5]

[0113] In the current interrupting device described in the second aspect of the present invention, among the plurality of circuit breakers, the circuit breaker having the lowest operating temperature has a resistance between both ends in the on state that is smaller than a combined resistance between both ends of the other circuit breakers in the on state.

[0114] [Present invention 6]

[0115] According to the current interrupting device of the second invention, among the plurality of circuit breakers, the resistance between both ends of the circuit breaker having the lowest operating temperature in the on state is 2% to 201% of the combined resistance between both ends of the other circuit breakers in the on state.

[0116] [Present invention 7]

[0117] In the current interrupting device described in the first aspect of the present invention, the plurality of circuit breakers include one or more first circuit breakers having a positive characteristic thermistor for conducting the fixed piece with the movable piece when the movable piece is in the interrupting state.

[0118] [Present invention 8]

[0119] In the current interrupting device according to the seventh aspect of the present invention, the plurality of circuit breakers include one or more second circuit breakers, and the second circuit breakers do not have the positive characteristic thermistor.

[0120] [Present invention 9]

[0121] According to the current breaking device of the eighth aspect of the present invention, the circuit breaker having the highest recovery temperature for recovering from the blocking state to the conducting state among the plurality of circuit breakers is the first circuit breaker.

[0122] [Present invention 10]

[0123] In the current breaking device according to the ninth aspect of the present invention, the number of the second circuit breakers included in the plurality of circuit breakers, the operating temperature of which is higher than the operating temperature of the first circuit breaker having the highest recovery temperature, is one or less.

[0124] [Present invention 11]

[0125] In the current breaking device according to the tenth aspect of the present invention, the plurality of circuit breakers include the circuit breaker whose operating temperature is lower than the operating temperature of the first circuit breaker having the highest recovery temperature.

[0126] [Present invention 12]

[0127] In the current interrupting device according to the first aspect of the present invention, the plurality of circuit breakers are composed of the same fixed piece and the same movable piece.

[0128] [Present invention 13]

[0129] A charge and discharge control circuit, comprising:

[0130] A current interrupting device as described in any one of items 1 to 12 of the present invention;

[0131] A secondary battery pack connected in series with the current interrupting device;

[0132] a power supply unit for supplying power to the secondary battery pack or a load for supplying power to the secondary battery pack;

[0133] The control unit controls the charging current from the power supply unit or the discharging current to the load based on the resistances at both ends of the current interrupting device.

[0134] Description of Reference Numerals

[0135] 1 Circuit breaker

[0136] 1A No.1 circuit breaker

[0137] 1B 2nd circuit breaker

[0138] 1B1 2nd circuit breaker

[0139] 1B2 2nd circuit breaker

[0140] 2Fixing piece

[0141] 4 movable pieces

[0142] 5Thermal response element

[0143] 6Thermistor

[0144] 21 Fixed contacts

[0145] 41 Movable contact

[0146] 44 Elastic part

[0147] 100 Current interrupting device

[0148] 200 charge and discharge control circuit

[0149] 201 Secondary battery pack

[0150] 202 Power Supply Department

[0151] 203 Load

[0152] 204 Control Unit.

Claims

1. A current interrupting device, which is a current interrupting device for interrupting current, characterized in that: It is composed of multiple circuit breakers connected in parallel. The circuit breaker comprises: a fixed piece having a fixed contact; a movable piece having an elastic portion capable of elastic deformation and a movable contact, wherein the movable contact is pressed against the fixed contact to contact the fixed contact; and a thermal response element, which deforms with temperature changes to change the state of the movable piece from a conducting state in which the movable contact contacts the fixed contact to a blocking state in which the movable contact is separated from the fixed contact, wherein the operating temperatures at which the state of the movable piece changes from the conducting state to the blocking state are different in the plurality of circuit breakers.

2. The current interrupting device according to claim 1, characterized in that: The resistance between both ends of at least one of the circuit breakers in the on state is different from the resistance between both ends of the other circuit breakers in the on state.

3. The current interrupting device according to claim 2, characterized in that: Among the plurality of circuit breakers, the circuit breaker having the highest operating temperature has a resistance between both ends in the conducting state that is greater than the resistance between both ends of the other circuit breakers in the conducting state.

4. The current interrupting device according to claim 2, characterized in that: Among the plurality of circuit breakers, the circuit breaker having the lowest operating temperature has a resistance between both ends in the conducting state that is smaller than the resistance between both ends of the other circuit breakers in the conducting state.

5. The current interrupting device according to claim 2, characterized in that: Among the plurality of circuit breakers, the circuit breaker having the lowest operating temperature has a resistance between both ends in the conducting state that is smaller than a combined resistance between both ends of the other circuit breakers in the conducting state.

6. The current interrupting device according to claim 2, characterized in that: Among the plurality of circuit breakers, the circuit breaker having the lowest operating temperature has a resistance between both ends in the conducting state that is 2% to 201% of a combined resistance between both ends in the other circuit breakers in the conducting state.

7. The current interrupting device according to claim 1, characterized in that: The plurality of circuit breakers include one or more first circuit breakers having a positive characteristic thermistor for conducting the fixed piece and the movable piece when the movable piece is in the blocking state.

8. The current interrupting device according to claim 7, characterized in that: The plurality of circuit breakers include one or more second circuit breakers, and the second circuit breakers do not include the positive characteristic thermistor.

9. The current interrupting device according to claim 8, characterized in that: Among the plurality of circuit breakers, the circuit breaker having the highest recovery temperature for recovering from the blocking state to the conducting state is the first circuit breaker.

10. The current interrupting device according to claim 9, characterized in that: The number of the second circuit breakers included in the plurality of circuit breakers, the operating temperature of which is higher than the operating temperature of the first circuit breaker having the highest recovery temperature, is one or less.

11. The current interrupting device according to claim 10, characterized in that: The plurality of circuit breakers include the circuit breaker having the operating temperature lower than the operating temperature of the first circuit breaker having the highest recovery temperature.

12. The current interrupting device according to claim 1, characterized in that: The plurality of circuit breakers are formed by the same fixed piece and the same movable piece.

13. A charge and discharge control circuit, characterized in that: include: The current interrupting device according to any one of claims 1 to 12; A secondary battery pack connected in series with the current interrupting device; a power supply unit for supplying power to the secondary battery pack or a load for supplying power to the secondary battery pack; The control unit controls the charging current from the power supply unit or the discharging current to the load based on the resistances at both ends of the current interrupting device.

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