CN114300320A - Circuit protection device integrating excitation fuse and relay protection function - Google Patents

Abstract

A circuit protection device integrating excitation fuses and relay protection functions comprises a shell, a movable contact component, a movable contact transmission component and a static contact component which are positioned in the shell, and an excitation module which is detachably arranged in the shell and comprises an excitation source and a power device; after the melt passes through the arc extinguishing chamber, two ends of the melt are respectively positioned on the shell at one side of different static contact components; under the normal working state, the melt is in non-conductive connection with the main circuit; when the fault current is zero or small, the moving contact driving component drives the moving contact to be separated from the contact with the static contact component; when the fault current is large, the moving contact transmission assembly is powered off, and simultaneously the excitation source drives the power device to act and simultaneously drives the melt to be connected with the main circuit in parallel, so that the moving contact assembly and the fixed contact assembly are driven to be separated from contact, and the melt is disconnected. The invention has small volume and compact structure, is suitable for the combined place of the exciting fuse and the relay, and can save the use space.

Description

A circuit protection device integrating excitation fuse and relay protection

technical field

The invention belongs to the field of electric power control and electric vehicles, in particular to a switch device for electric power/electric vehicles.

Background technique

At present, electric vehicle battery pack protection devices are mainly traditional thermal fuses or excitation fuses and relays. The fuse is a protection device that uses the current heat accumulation effect to make the current sensing point (neck) set by the melt melt and disconnect and extinguish the arc within a certain period of time. The excitation fuse is a kind of fast protection device that uses the electronic gas generating device to push the insulator to cut off the conductor to form a physical fracture in a short time. A relay is a repeatable protective device that connects or disconnects the main circuit conductor through small current control.

The traditional fuse works by using the heat accumulation effect of the current, so its advantage is that under the large multiple fault current, the fusing action will respond quickly; on the contrary, in the small multiple fault current, the fusing action will prolong the response. And the traditional fuse is affected by its structure, and the device is a one-time device. The operating characteristics of relays complement the advantages and disadvantages of traditional fuses. The advantage of the relay is that in the small multiple fault current, the action response is fast, the breaking efficiency is high, and within its breaking range, it can be broken and closed multiple times without affecting its working performance; the disadvantage is that its breaking upper limit is low, when the fault current is greater than Its breaking upper limit, when the moving and static contacts of the relay are in action, will be damaged, which will affect the working performance of the device. The advantage of the excitation fuse over the traditional fuse is that the breaking is actively controlled, and it can also break quickly under a small multiple fault current, but its product structure also determines that the device is a one-time protection device.

The circuit design and power flow in electric vehicles is a complex system, in which there are often low multiple fault current surges, which are a challenge to the one-time action protection characteristics of excitation fuses and traditional fuses , it is also a potential threat to the safe operation requirements of the main circuit. Combined with the protection characteristics of relays under small multiple fault currents, if the relays and excitation fuses are connected in series to the main circuit system, not only can the system's requirements for the excitation fuses against inrush current be reduced, but also the safety of the circuit system. An enhancement and reinforcement.

The advantage of the excitation fuse and relay protection scheme is that under a small multiple fault current, the relay can act to disconnect the fault circuit, and the excitation fuse will not operate; under medium and large multiple fault currents, the excitation fuse will actively act to disconnect the fault. current, the relay does not operate. The disadvantage of this protection scheme is that in order to achieve the same circuit protection function, two parts need to be arranged in the battery pack for protection, which is a great waste of space in the battery pack, and also increases the weight and cost of the battery pack.

How to integrate the relay and the excitation fuse together without interfering with each other is a technical problem that needs to be solved urgently at present.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a protection device that integrates the excitation fuse and the relay. By redesigning the space structure of the relay, the main structure of the excitation fuse is arranged in the internal space of the relay, so as to combine the functions of the two devices. The integration is carried out, which greatly reduces the space size and weight of the device, and reduces the cost of the device.

In order to achieve the above purpose, the technical solution provided by the present invention is a circuit protection device integrating excitation fuse and relay protection functions, comprising a casing, a moving contact assembly, a moving contact transmission assembly, and a static contact located in the casing. The head assembly is characterized in that an excitation module is detachably arranged in the casing, the excitation module includes an excitation source and a power device; the melt passes through an arc-extinguishing chamber filled with an arc-extinguishing medium in the casing Afterwards, its two ends are respectively arranged on the shells on one side of different static contact assemblies; under normal working conditions, the melt is non-conductively connected to the main circuit; when there is zero fault current or small fault current, the moving contact drives When the component is powered off, the moving contact and the static contact component are out of contact; when a large fault current occurs, the moving contact transmission component is powered off, and the excitation source drives the power device to act according to the received excitation signal, and drives the After the melt is connected in parallel with the main circuit, the power device drives the movable contact assembly to disconnect from the conductive connection with the static contact assembly, and drives the movable contact assembly to disconnect the melt.

Preferably, after the excitation source drives the power device according to the received excitation signal to push the movable contact assembly and the stationary contact assembly out of conductive connection, the movable contact assembly disconnects the melt .

Preferably, a conducting device is further provided in the housing, and the conducting device is communicated with the cavity where the excitation source is located through an air passage; when the excitation source is actuated, the conducting device can be driven to melt the melting point. The body is connected in parallel with the main circuit.

Preferably, a conductive elastic sheet is provided on the static contact, and the conduction device drives the conductive elastic sheet to conduct conductive connection with the end of the melt, so that the melt is connected in parallel with the main circuit.

Preferably, the excitation module includes an excitation casing, and a first cavity and a second cavity are opened in the excitation casing; the excitation source and the power device are arranged in the first cavity, and the conduction The device is arranged in the second cavity, and the second cavity is communicated with the first cavity through an air passage; the excitation source can simultaneously drive the power device and the conduction device to act.

Preferably, the moving contact assembly includes a connecting rod connected with the moving contact transmission assembly, and the connecting rod disconnects the melt.

Preferably, the arc-extinguishing chamber includes an accommodating groove provided in the housing, and an arc-extinguishing chamber cover plate is detachably provided on the accommodating groove.

Preferably, the melt is provided with at least one fusing weak point, and the fusing weak point is located in the arc extinguishing chamber.

Preferably, the melt is provided with at least one breaking weak point, the breaking weak point is located in the arc extinguishing chamber, and the melt is broken from the breaking weak point.

Preferably, a positioning device for positioning the melt is provided in the arc extinguishing chamber.

Preferably, the movable contact assembly is located in a housing between the arc extinguishing chamber and the stationary contact assembly; the arc extinguishing chamber and the stationary contact assembly define a displacement distance of the movable contact assembly.

The circuit protection device of the present invention organically integrates the excitation fuse and the relay, and when there is a small fault current or zero fault current, the main circuit is turned on and off through the conductive contact or disengagement of the moving and static contacts, so that the protection device can be reused; When there is a large fault current, the moving and static contacts are forced out of contact through the excitation module, and the arc is extinguished in the arc-extinguishing chamber through melt disconnection. The circuit protection device of the present invention is small in size and compact in structure, can realize breaking in the full current range, and the relay part can be reused. After the excitation module works, the circuit protection device can be reused by replacing the excitation module and the melt.

Description of drawings

FIG. 1 is a schematic diagram of the conductive contact structure of the moving and static contacts under normal working conditions.

FIG. 2 is a schematic diagram of the structural relationship between the conducting device, the conductive elastic sheet, and the melt under a normal working state or a state where the excitation source is not actuated, and a partial enlarged view A. FIG.

Figure 3 is a schematic diagram of the separation structure of the moving and static contacts when a small current fault occurs.

Figure 4 is a schematic diagram of the structure when the power unit drives the moving contact and the static contact to separate and the melt is not disconnected when a high current fault occurs.

Fig. 5 is a schematic diagram of the structural relationship and a partial enlarged view A in which the excitation source and the power device act, and the conduction device connects the conductive shrapnel and the melt when a high current fault occurs.

Fig. 6 is a schematic diagram of the melt blown structure when the power unit drives the movable contact and the static contact to separate when a high current fault occurs.

Figure 7 is a schematic diagram of the structure of the disconnection of the drive assembly of the melt passive contact when the power device drives the moving contact to separate from the static contact in the event of a high current fault.

Detailed ways

For the above-mentioned technical solution, a preferred embodiment is given and a specific description is given with reference to FIGS. 1 to 6 .

Referring to FIG. 1 , a housing 204 is included, and the housing 204 is mainly provided with a moving contact transmission assembly, a moving contact assembly, a stationary contact assembly, an excitation module, an arc extinguishing chamber 215, and a melt 209, wherein:

The casing 204 is made of insulating material. The moving contact transmission assembly, which is a traditional relay moving contact transmission device, is independently located in the bottom space in the housing 204 . An isolation support plate is arranged between the movable contact assembly and the movable contact transmission assembly to separate the movable contact assembly and the movable contact transmission assembly. The moving contact transmission assembly includes an excitation coil, through which the linear displacement driving block 210 is driven, and the driving block 210 is connected with the support plate through a spring. Driven by the magnetic force generated by the excitation coil, the driving block 210 can be displaced in the direction of the stationary contact assembly, and vertically compress the spring connected with it. A certain displacement gap remains between the initial position of the driving block 210 and the bottom of the housing 204 .

The movable contact assembly includes a connecting rod 213, and the connecting rod 213 is connected with a support plate through a spring, and the moving contact 207 is provided on the support plate. The rod part of the connecting rod 213 is fixedly connected with the driving block 210 through the support plate. The connecting rod 213 is similar to a T-shaped structure, and its connecting end with the supporting plate is a large diameter end, and two step structures (213a, 213b) are designed on it, wherein the step structure 213a on the side close to the driving block is used for limiting The displacement distance of the connecting rod toward the bottom of the casing is limited by being clamped on the support plate by the step structure 213 a , and the step structure 213 b is used to disconnect the melt 209 .

The moving contact is made of conductive metal material with certain rigidity and strength.

The static contact assembly includes at least two spaced static contacts 206 , a conductive elastic piece 211 is electrically connected to the static contact 206 , and the conductive elastic piece protrudes from the side of the static contact 206 and is suspended. The static contacts 206 are respectively electrically connected with terminals 202, and the terminals 202 extend out of the housing 204 and can be connected to an external main circuit. The static contact 206 is made of conductive metal material, and the terminal is also made of conductive metal material.

When the excitation coil is energized, the driving block 210 is driven to move, and the movable contact assembly is driven to displace and make conductive contact with the static contact to connect the main circuit.

At least one arc-extinguishing chamber 215 is disposed in the outer casing of the connecting rod 213 , and the arc-extinguishing chamber includes an arc-extinguishing housing 208 , which is sealed by a cover plate 214 . The arc extinguishing chamber 215 is filled with an arc extinguishing medium. The melt 209 passes through the space between the connecting rod 213 and the driving block 210, and after passing through the arc-extinguishing chamber 215, the two ends of the melt respectively pass through the arc-extinguishing chamber and are arranged on the housing on one side of the static contact 206, and It is located just below the conductive elastic sheet suspended on the side extending out of the static contact, and the melt does not contact the static contact 206; when the melt and the static contact are electrically connected through the conduction device 212, the melt is connected in parallel with the main circuit . When the connecting rod is displaced by the excitation coil, it will not affect the melt structure. But when the movable contact assembly is driven by the excitation module, the connecting rod stepped structure 213b will break the melt. The movable contact is located in the housing space between the static contact assembly and the arc extinguishing chamber, and the displacement distance of the movable contact is limited by the static contact and the arc extinguishing chamber.

The melt located in the arc extinguishing chamber is provided with at least one fusing weak point, and the fusing weak point is a narrow neck, or a metallurgical effect point, or the narrow neck is combined with the metallurgical effect point. A disconnection weak point is arranged at the position where the connecting rod breaks the melt, so as to reduce the mechanical strength of the melt and facilitate the connecting rod to break the melt. The breaking weak point of the melt can be located in the arc-extinguishing chamber or outside the arc-extinguishing chamber. A positioning structure for positioning the melt, such as a positioning column, is arranged in the arc extinguishing chamber, so that the melt is penetrated on the positioning column to realize the melt positioning. When the melt passes through the arc-extinguishing chamber, it can pass through the gap left between the arc-extinguishing chamber and the cover plate for the melt to pass through.

An excitation module is fixedly arranged in the housing between the static contacts in a detachable manner. The excitation module includes an excitation housing 203 , and an excitation source 201 , a power device 205 and a conduction device 504 are arranged in the excitation housing 203 . A through first cavity 203a is opened in the excitation shell, and the excitation source 201 and the power device 205 are arranged in the first cavity. The excitation source 201 is positioned by a limiting step in the first cavity of the excitation casing and a pressing plate (not shown) disposed outside the casing 204 . The power device 205 is defined in an initial position by a limiting structure. The limit structure may be a limit bump on the power device, a limit groove on the inner wall of the excitation shell, and the limit bump is clamped in the limit groove to form the limit structure. The power unit 205 is in sealing contact with the excitation housing. The power device may also be in interference fit with the first cavity to achieve initial position definition and at the same time to achieve sealing contact. A certain gap is reserved between the power device 205 and the excitation source 201 . The end face of the power device at one end of the excitation source is set as a concave face. The excitation source 201 is a gas generating device, which can release high-pressure gas to drive the power device to move against the limiting structure. The power unit 205 is located directly in front of the movable contact. The power device 205 is a piston block, and the end face on one side of the movable contact is a plane. When the moving contact is in conductive contact with the static contact and a large fault current occurs, the excitation source 201 receives the excitation signal to drive the power device to move against the limit structure, and the power device is displaced to the end face of the moving contact to drive the displacement of the moving contact and the static contact Disconnect from conductive connection. The contact surface between the power device and the moving contact is flat, which can ensure that the force area of the moving contact is increased, and the moving contact will not be damaged by impact.

A second cavity 203b with one end open is respectively provided on the excitation housings on both sides of the power device, a conducting device 212 is provided in the second cavity, and the open end of the second cavity is located between the conductive elastic sheet of the static contact and the Directly in front of the melt end. The conducting device 212 is in sealing contact with the second cavity, and the conducting device 212 can be limited to its initial position by the limiting structure. Location restricted. A gap is reserved between the conduction device and the bottom of the second cavity, and the gap communicates with the gap between the power device and the excitation source in the first cavity through the flow channel. The distance between the conducting device 212 and the end of the melt is smaller than the distance between the power device and the moving contact which is in contact with the stationary contact.

During normal operation, the excitation coil is energized, and the moving contact is in conductive contact with the static contact driven by the magnetic force of the excitation coil, and the main circuit is connected. At this time, the melt is not connected to the static contact and the main circuit. The fault current threshold is set in the control system. When the fault current is small, the excitation coil is switched on and off to make the moving contact and the static contact contact and separate to control the opening and closing of the main circuit; when the fault current is large, the excitation coil is powered off to make the moving contact When the head and the static contact are separated, a large arc is generated at the fracture of the moving contact and the static contact, causing ablation damage to the moving contact and the static contact. Therefore, when the fault current is large, the control system sends an excitation signal to the excitation source, and at the same time, the power supply circuit of the control coil is disconnected, so that the excitation coil is powered off. The flow channel drives the conduction device to displace, and the conduction device drives the conductive shrapnel of the static contact to make conductive contact with the end of the melt, so that the melt is connected in parallel with the main circuit; then, the power device drives the moving contact to disengage from the static contact, reacting The time is about 2ms. Due to the existence of the parallel melt, when the moving contact is out of contact with the static contact, about 70% of the fault current flows through the melt, and the current at the fracture of the moving contact and the static contact is very small, resulting in very small or No arc will be generated, and no damage will be caused to the moving contact and the static contact; because the fault current flows through the melt, the melt is fused at the weak point of the fuse, and the main circuit is disconnected, and the arc generated by the melt blown fracture is extinguished by the arc extinguishing medium. arc. When the melt can not be blown for the first time, the moving contact assembly is displaced under the drive of the power device, and the connecting rod disconnects the melt from the weak point of the melt to cut off the main circuit. Since the weak point is located in the arc extinguishing medium, the melting point The arc is extinguished by the arc extinguishing medium at the disconnection of the body.

After the excitation coil is powered off, it takes at least ten milliseconds for the moving contact and the static contact to break out of contact, while the response time of the excitation module is about 2ms. When the excitation coil is powered off and cannot provide magnetic support for the moving contact, the power The device drives the moving contact out of contact with the static contact under the action of no magnetic block.

After the circuit is disconnected, in subsequent maintenance, the device of the present invention only needs to be disassembled, and the melt and the excitation module can be replaced, and the components of the relay do not need to be replaced.

Claims (11)

1. A circuit protection device integrating excitation fuse and relay protection functions comprises a shell, a movable contact component, a movable contact transmission component and a fixed contact component, wherein the movable contact component, the movable contact transmission component and the fixed contact component are positioned in the shell; the two ends of the melt are respectively arranged on the shell at one side of different static contact components after the melt passes through an arc extinguishing chamber filled with arc extinguishing medium in the shell; under the normal working state, the melt is in non-conductive connection with the main circuit; when the fault current is zero or small, the moving contact transmission assembly is powered off, and the moving contact is separated from the static contact assembly; when the fault current is large, the moving contact transmission assembly is powered off, the excitation source drives the power device to act according to the received excitation signal, and simultaneously drives the melt to be connected with the main circuit in parallel, and after the power device drives the moving contact assembly to be separated from the static contact assembly and electrically connected, the moving contact assembly is driven to disconnect the melt.

2. The circuit protection device of claim 1, wherein the movable contact assembly disconnects the melt when the excitation source drives the power device to push the movable contact assembly out of conductive connection with the stationary contact assembly according to the received excitation signal.

3. The circuit protection device according to claim 1, wherein a conducting device is further disposed in the housing, and the conducting device is communicated with the cavity in which the excitation source is located through an air passage; when the excitation source acts, the conducting device can be driven to connect the melt and the main circuit in parallel.

4. The circuit protection device of claim 3, wherein a conductive spring is disposed on the stationary contact, and the conducting device drives the conductive spring to be conductively connected with the end of the melt, so that the melt is connected in parallel with the main circuit.

5. The circuit protection device of claim 3, wherein the excitation module comprises an excitation housing having a first cavity and a second cavity formed therein; the excitation source and the power device are arranged in the first cavity, the conduction device is arranged in the second cavity, and the second cavity is communicated with the first cavity through an air passage; the excitation source can drive the power device and the conducting device to act simultaneously.

6. The circuit protection device of claim 2, wherein the movable contact assembly includes a connecting rod connected to the movable contact drive assembly, the connecting rod breaking the melt.

7. The circuit protection device of claim 1, wherein the arc extinguishing chamber includes a receiving slot disposed in the housing, an arc extinguishing chamber cover plate being removably disposed on the receiving slot.

8. The circuit protection device of claim 1, wherein the fuse element has at least one fuse weak point disposed thereon, the fuse weak point being located in the arc quenching chamber.

9. The circuit protection device of claim 2, wherein the melt is provided with at least one break weakness therein, the break weakness being located in the arc quenching chamber, the melt breaking away from the break weakness.

10. The circuit protection device of claim 2, wherein a positioning device is provided in the arc-extinguishing chamber to position the melt.

11. The circuit protection device of claim 1, wherein the movable contact assembly is located within a housing between the arc extinguishing chamber and the stationary contact assembly; the arc extinguishing chamber and the static contact component limit the displacement distance of the moving contact component.

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